U.S. patent application number 11/133796 was filed with the patent office on 2006-08-24 for autonomous surface cleaning robot for dry cleaning.
Invention is credited to Duane JR. Gilbert, Andrew Jones, Christopher John Morse, Andrew Ziegler.
Application Number | 20060190132 11/133796 |
Document ID | / |
Family ID | 36913840 |
Filed Date | 2006-08-24 |
United States Patent
Application |
20060190132 |
Kind Code |
A1 |
Morse; Christopher John ; et
al. |
August 24, 2006 |
Autonomous surface cleaning robot for dry cleaning
Abstract
An autonomous floor cleaning robot includes a transport drive
and control system arranged for autonomous movement of the robot
over a floor for performing cleaning operations. The robot chassis
carries cleaning elements arranged to suction loose particulates up
from the cleaning surface. The cleaning elements include a jet port
disposed on a transverse edge of the robot and configured to blow a
jet of air across a cleaning width of the robot towards the
opposite transverse edge and a vacuum intake port is disposed on
the robot opposed to the jet port to suction up loose particulates
blown across the cleaning width by the jet port.
Inventors: |
Morse; Christopher John;
(Malden, MA) ; Ziegler; Andrew; (Arlington,
MA) ; Gilbert; Duane JR.; (Goffstown, NH) ;
Jones; Andrew; (Roslindale, MA) |
Correspondence
Address: |
GOODWIN PROCTER LLP;PATENT ADMINISTRATOR
EXCHANGE PLACE
BOSTON
MA
02109-2881
US
|
Family ID: |
36913840 |
Appl. No.: |
11/133796 |
Filed: |
May 21, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60654838 |
Feb 18, 2005 |
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Current U.S.
Class: |
700/245 |
Current CPC
Class: |
A47L 11/4041 20130101;
A47L 11/302 20130101; A47L 7/0028 20130101; A47L 11/4088 20130101;
A47L 11/4011 20130101; A47L 11/4002 20130101; A47L 2201/00
20130101; A47L 11/4016 20130101; A47L 11/4044 20130101; A47L
11/4069 20130101; A47L 7/0009 20130101; A47L 7/0042 20130101; A47L
5/14 20130101; A47L 7/0038 20130101 |
Class at
Publication: |
700/245 |
International
Class: |
G06F 19/00 20060101
G06F019/00 |
Claims
1. A surface cleaning apparatus comprising: a chassis (200) defined
by a fore-aft axis 106 and a perpendicular transverse axis (108),
the chassis (200) being supported for transport over the surface
along the fore-aft axis (106), the chassis (200) including a first
collecting apparatus A attached thereto and configured to collect
loose particulates from the surface over a cleaning width disposed
generally parallel with the transverse axis (108), the first
collecting apparatus comprising: an air jet port (554) configured
to expel a jet of air across the cleaning width; an air intake port
(556) configured to draw air and loose particulates in; and,
wherein the air jet port (554) and the air intake port (556) are
disposed at opposing ends of the cleaning width with the air jet
port (554) expelling the jet of air generally parallel with the
surface and generally directed toward the air intake port
(556).
2. A surface cleaning apparatus according to claim 1 wherein the
first collecting apparatus A further comprises: a channel formed
with generally opposed forward and aft edges, extending generally
parallel with the transverse axis (108) across the cleaning width,
and generally opposed left and right edges, extending generally
orthogonal to said forward and aft edges; and, wherein the air jet
port (554) is disposed at one of said left and right edges and the
air intake port (556) is disposed at the other of said left and
right edges.
3. A surface cleaning apparatus according to claim 2 further
comprising a first compliant doctor blade (576) disposed across the
cleaning width and fixedly attached to a bottom surface of the
chassis (200) proximate to said aft edge and extending from said
bottom surface to the surface for guiding the jet of air and loose
particulates across the cleaning width.
4. A surface cleaning apparatus according to claim 3 further
comprising a second compliant doctor blade fixedly attached to said
bottom surface and extending from said bottom surface to the
surface, for guiding the jet of air and loose particulates into the
air intake port (556).
5. A surface cleaning apparatus according to claim 1 further
comprising the following elements attached to the chassis (200): a
rotary fan motor (504) having a fixed housing (506) and a rotating
shaft (508) extending therefrom; a fan impeller (512) configured to
move air when rotated about a rotation axis, said fan impeller
(512) being fixedly attached to the rotating shaft (508) for
rotation about the rotation axis by the fan motor (512); housing
means for housing the fan impeller (512) in a hollow cavity formed
therein and for fixedly supporting the motor fixed housing (506)
thereon, the housing means being further configured with an air
intake port (516) through which air is drawn in to the cavity, and
an air exit port ((518)) through which air is expelled out of the
cavity when the impeller (512) is rotated; and, a first fluid
conduit fluidly connected between the fan air intake port (516) and
the air intake port (556) of said first collecting apparatus A.
6. A surface cleaning apparatus according to claim 5 further
comprising a waste storage container W attached to the chassis
(200) and fluidly interposed within said first fluid conduit
between the fan air intake port (516) and the air intake port
(556).
7. A surface cleaning apparatus according to claim 6 wherein the
waste storage container W is configured to be removable from the
chassis (200) by a user and to be emptied by the user.
8. A surface cleaning apparatus according to claim 7 further
comprising an air filter element interposed within said first fluid
conduit between the waste storage container W and the fan air
intake port (516) for filtering loose contaminates from air being
drawn in through the fan air intake port (516).
9. A surface cleaning apparatus according to claim 8 further
comprising a second fluid conduit fluidly connected between the fan
exit port ((518)) and the air jet port (554) of said first
collecting apparatus A.
10. A surface cleaning apparatus according to claim 1 further
comprising a second collecting apparatus B attached to the chassis
(200) and disposed aft of the first collecting apparatus A for
collecting liquid from the surface over the cleaning width.
11. A surface cleaning apparatus according to claim 10 wherein the
second collecting zone B comprises: a squeegee (630) fixedly
attached to the chassis (200) aft of the first collecting apparatus
A and extending from a bottom surface of the chassis (200) to the
surface across the cleaning width for collecting liquid in a liquid
collection volume formed between the squeegee (630) and the
surface, the squeegee 630 further forming a vacuum chamber (1016)
and providing a plurality of suction ports (1012) disposed across
the cleaning width and fluidly connecting the vacuum chamber (1016)
and the liquid collection volume; and, means for generating a
negative air pressure inside the vacuum chamber to thereby draw
liquid into the vacuum chamber through the plurality of suction
ports fluidly connected with the collection volume.
12. A surface cleaning apparatus according to claim 11 further
comprising the following elements attached to the chassis (200): a
rotary fan motor (504) having a fixed housing (506) and a rotating
shaft (508) extending therefrom; a fan impeller (512) configured to
move air when rotated about a rotation axis, said fan impeller
(512) being fixedly attached to the rotating shaft (508) for
rotation about the rotation axis by the fan motor (512); housing
means for housing the fan impeller (512) in a hollow cavity formed
therein and for fixedly supporting the motor fixed housing (506)
thereon, the housing means being further configured with an air
intake port (516) through which air is drawn in to the cavity, and
an air exit port (518) through which air is expelled out of the
cavity when the impeller (512) is rotated; a first fluid conduit
fluidly connected between the fan air intake port (516) and the air
intake port (556) of said first collecting apparatus A; and, a
third fluid conduit fluidly connected between the fan air intake
port (516) and the vacuum chamber.
13. A surface cleaning apparatus according to claim 12 further
comprising a second fluid conduit fluidly connected between the fan
exit port (518) and the air jet port (554) of said first collecting
apparatus A.
14. A surface cleaning apparatus according to claim 10 further
comprising a waste storage container W attached to the chassis
(200) and configured to store the liquid collected from the
surface.
15. A surface cleaning apparatus according to claim 12 further
comprising a waste storage container W attached to the chassis
(200) and configured to store the liquid collected from the
surface, said waste storage container being fluidly interposed
within said third fluid conduit.
16. A surface cleaning apparatus according to claim 13 further
comprising a waste storage container W attached to the chassis
(200) and configured to store the liquid collected from the
surface, said waste storage container being fluidly interposed
within said first and said third fluid conduits.
17. A surface cleaning apparatus according to claim 13 wherein said
waste storage container W comprises: a sealed waste container D for
storing loose particulates collected by the first collecting
apparatus A and for storing liquid collected by the second
collecting apparatus B and having at least one access port formed
therein for emptying waste from the container D; and, a plenum
(562) incorporated into a top wall of the sealed container D such
that the plenum (562) is disposed vertically above the sealed waste
container D during operation of the cleaning apparatus; and wherein
the plenum (562) is configured with ports for fluidly interposing
within each of said first, said second and said third fluid
conduits.
18. A surface cleaning apparatus according to claim 17 wherein the
waste storage container W is configured to be removable from the
chassis (200) by a user and to be emptied by the user.
19. A surface cleaning apparatus according to claim 17 further
comprising: a cleaning fluid applicator assembly (700), attached to
the chassis (200) between the first collecting apparatus A and the
second collecting apparatus B for applying a cleaning fluid onto
the surface across the cleaning width; and, a sealed cleaning fluid
storage container S for holding a supply of the cleaning fluid
therein the storage container S including at least one access port
formed therein for filling the container S with the cleaning
fluid.
20. A surface cleaning apparatus according to claim 19 wherein said
sealed waste container D and said sealed cleaning fluid container S
are integrated into a liquid storage container module (800) and
wherein the integrated liquid storage container module (800) is
configured to be removable from the chassis (200) by a user for
filling with cleaning fluid and for emptying waste therefrom.
21. A surface cleaning apparatus according to claim 20 further
comprising: a smearing element (612) attached the chassis (200) aft
of the liquid applicator assembly (700) and configured to smear the
cleaning fluid across the cleaning width; and, a scrubbing element
attached to the chassis (200) aft of the smearing element (612) for
scrubbing the surface across the cleaning width.
22. A surface cleaning apparatus according to claim 21 further
comprising a motive drive subsystem (900) controlled by a master
control module (300) and power by a power module (310), each
attached to the chassis (200), for autonomously transporting the
surface cleaning apparatus over the surface.
23. A surface cleaning apparatus according to 22 further
comprising: a sensor module (340) configured to sense conditions
and to generate electrical sensor signals in response to sensing
said conditions; means for communicating the electrical sensor
signals to the master control module (300); and, control means
incorporated within the master control module (300) for
implementing predefined operating modes in response to sensing said
conditions.
24. A surface cleaning apparatus according to claim 1 further
comprising a motive drive subsystem (900) controlled by a master
control module (300) and power by a power module (310), each
attached to the chassis (200), for autonomously transporting the
surface cleaning apparatus over the surface.
25. A surface cleaning apparatus according to 24 further
comprising: a sensor module (340) configured to sense conditions
and to generate electrical sensor signals in response to sensing
said conditions; means for communicating the electrical sensor
signals to the master control module (300); and, control means
incorporated within the master control module (300) for
implementing predefined operating modes in response to sensing said
conditions.
26. A surface cleaning apparatus comprising: an autonomous
transport drive subsystem (900) controlled by a master control
module (300), a sensor module (340) for sensing conditions, a power
module (310) and cleaning elements all supported on a chassis (200)
and powered by the power module (310) for moving the chassis (200)
over the surface in accordance with predefined operating modes and
in response to conditions sensed by the sensor module (340), the
elements being configured with a cleaning width disposed generally
orthogonal to a forward transport direction and wherein the
cleaning elements comprise; a first collecting apparatus A for
collecting loose particulates from the surface across the cleaning
width, said first collecting apparatus A being positioned on the
chassis to advance over the surface first as the chassis (200) is
transported in a forward transport direction; a cleaning fluid
applicator (700) for applying cleaning fluid onto the surface
across the cleaning width, said cleaning fluid applicator (700)
being positioned on the chassis to advance over the surface second
as the chassis (200) is transported in a forward transport
direction; a smearing element (614) for smearing the cleaning fluid
applied onto the surface across the cleaning width, said smearing
element (614) being positioned on the chassis to advance over the
surface third as the chassis (200) is transported in a forward
transport direction; an active scrubbing element (604) for actively
scrubbing the surface across the cleaning width, said active
scrubbing element (604) being positioned on the chassis to advance
over the surface fourth as the chassis (200) is transported in a
forward transport direction; a second collecting apparatus B for
collecting waste liquid from the surface, said second collecting
apparatus B being positioned on the chassis to advance over the
surface fifth as the chassis (200) is transported in a forward
transport direction; and, an integrated storage container module
(800) comprising a waste storage container D for storing loose
particulates collected by said first collecting apparatus A and
waste liquid collected by said second collecting apparatus B, a
cleaning fluid supply container S for storing a supply of the
cleaning fluid, and wherein the integrated storage container module
(800) is configured to be removed from the chassis (200) by a user,
filled with cleaning fluid and emptied of waste and then
reinstalled onto the chassis (200) by the user.
Description
PRIORITY CLAIM
[0001] This invention claims priority from Provisional Application
Ser. No. 60/654,839 filed Feb. 18, 2005.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] This application relates to co-pending and co-assigned
patent application Ser. No. ______ entitled AUTONOMOUS SURFACE
CLEANING ROBOT FOR DRY AND WET CLEANING; and patent application
Ser. No. ______, entitled AUTONOMOUS SURFACE CLEANING ROBOT FOR WET
CLEANING both of which are filed even dated herewith and
incorporated herein by this reference.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates to cleaning devices, and more
particularly, to an autonomous surface cleaning robot. In
particular, the surface cleaning robot includes two separate
cleaning zones with a first cleaning zone configured to collect
loose particulates from the surface and with a second cleaning zone
configured to apply a cleaning fluid onto the surface, scrub the
surface and thereafter collect a waste liquid from the surface. The
surface cleaning robot may also include at least two containers,
carried thereby, to store cleaning fluid and waste materials.
[0005] 2. Description of Related Art
[0006] Autonomous robot floor cleaning devices having a low enough
end user price to penetrate the home floor cleaning market are
known in the art. For example, co-assigned and co-pending U.S.
patent application Ser. No. 10/320,729 by Jones et al. entitled
AUTONOMOUS FLOOR-CLEANING ROBOT discloses an autonomous robot
comprising a chassis, a battery power subsystem, a motive drive
subsystem operative to propel the autonomous floor cleaning robot
over a floor surface for cleaning operations, a command and control
subsystem operative to control the cleaning operations and the
motive subsystem, a rotating brush assembly for sweeping up or
collecting loose particulates from the surface, a vacuum subsystem
for suctioning up or collecting loose particulates on the surface,
and a removable debris receptacle for collecting the particulates
and storing the loose particulates on the robot during operation.
Models similar to the device disclosed in the '729 application are
commercially marketed by IROBOT CORPORATION under the trade names
ROOMBA RED and ROOMBA DISCOVERY. These devices are operable to
clean hard floor surfaces, e.g. bare floors, as well as carpeted
floors, and to freely move from one surface type to the other
unattended and without interrupting the cleaning process.
[0007] In particular, the '729 application teaches a first cleaning
zone configured to collect loose particulates in a receptacle. The
first cleaning zone includes a pair of counter-rotating brushes
engaging the surface to be cleaned. The counter-rotating brushes
are configured with brush bristles that move at an angular velocity
with respect to floor surface as the robot is transported over the
surface in a forward transport direction. The angular movement of
the brush bristles with respect to the floor surface tends to flick
loose particulates laying on the surface into the receptacle which
is arranged to receive flicked particulates.
[0008] The '729 application further teaches a second cleaning zone
configured to collect loose particulates in the receptacle and
positioned aft of the first cleaning zone such that the second
cleaning zone performs a second cleaning of the surface as the
robot is transported over the surface in the forward direction. The
second cleaning zone includes a vacuum device configured to suction
up any remaining particulates and deposit them into the
receptacle.
[0009] In other examples, home use autonomous cleaning devices are
disclosed in each of U.S. Pat. No. 6,748,297, and U.S. Patent
Application Publication No. 2003/0192144, both by Song et al. and
both assigned to Samsung Gwangiu Electronics Co. In these examples,
autonomous cleaning robots are configured with similar cleaning
elements that utilize rotating brushes and a vacuum device to flick
and suction up loose particulates and deposit them in a
receptacle.
[0010] While each of the above examples provide affordable
autonomous floor clearing robots for collecting loose particulates,
there is heretofore no teaching of an affordable autonomous floor
cleaning robot for applying a cleaning fluid onto the floor to wet
clean floors in the home. A need exists in the art for such a
device and that need is addressed by the present invention.
[0011] Wet floor cleaning in the home has long been done manually
using a wet mop or sponge attached to the end of a handle. The mop
or sponge is dipped into a container filled with a cleaning fluid,
to absorb an amount of the cleaning fluid in the mop or sponge, and
then moved over the surface to apply a cleaning fluid onto the
surface. The cleaning fluid interacts with contaminates on the
surface and may dissolve or otherwise emulsify contaminates into
the cleaning fluid. The cleaning fluid is therefore transformed
into a waste liquid that includes the cleaning fluid and
contaminates held in suspension within the cleaning fluid.
Thereafter, the sponge or mop is used to absorb the waste liquid
from the surface. While clean water is somewhat effective for use
as a cleaning fluid applied to floors, most cleaning is done with a
cleaning fluid that is a mixture of clean water and soap or
detergent that reacts with contaminates to emulsify the
contaminates into the water. In addition, it is known to clean
floor surfaces with water and detergent mixed with other agents
such as a solvent, a fragrance, a disinfectant, a drying agent,
abrasive particulates and the like to increase the effectiveness of
the cleaning process.
[0012] The sponge or mop may also be used as a scrubbing element
for scrubbing the floor surface, and especially in areas where
contaminates are particularly difficult to remove from the floor.
The scrubbing action serves to agitate the cleaning fluid for
mixing with contaminates as well as to apply a friction force for
loosening contaminates from the floor surface. Agitation enhances
the dissolving and emulsifying action of the cleaning fluid and the
friction force helps to break bonds between the surface and
contaminates.
[0013] One problem with the manual floor cleaning methods of the
prior art is that after cleaning an area of the floor surface, the
waste liquid must be rinsed from the mop or sponge, and this
usually done by dipping the mop or sponge back into the container
filled with cleaning fluid. The rinsing step contaminates the
cleaning fluid with waste liquid and the cleaning fluid becomes
more contaminated each time the mop or sponge is rinsed. As a
result, the effectiveness of the cleaning fluid deteriorates as
more of the floor surface area is cleaned.
[0014] While the traditional manual method is effective for floor
cleaning, it is labor intensive and time consuming. Moreover, its
cleaning effectiveness decreases as the cleaning fluid becomes
contaminated. A need exists in the art for an improved method for
wet cleaning a floor surface to provide an affordable wet floor
cleaning device for automating wet floor cleaning in the home.
[0015] In many large buildings, such as hospitals, large retail
stores, cafeterias, and the like, there is a need to wet clean the
floors on a daily or nightly basis, and this problem has been
addressed by the development of industrial floor cleaning robots
capable of wet cleaning floors. An example of one industrial wet
floor cleaning device is disclosed in U.S. Pat. No. 5,279,672 by
Betker et al., and assigned to Windsor Industries Inc. Betker et
al. disclose an autonomous floor cleaning device having a drive
assembly providing a motive force to autonomously move the wet
cleaning device along a cleaning path. The device provides a
cleaning fluid dispenser for dispensing cleaning fluid onto the
floor; rotating scrub brushes in contact with the floor surface for
scrubbing the floor with the cleaning fluid, and a waste liquid
recovery system, comprising a squeegee and a vacuum system for
recovering the waste liquid from the floor surface. While the
device disclosed by Betker et al. is usable to autonomously wet
clean large floor areas, it is not suitable for the home market. In
particular, the industrial autonomous cleaning device disclosed by
Betker et al. is too large, costly and complex for use in the home
and consumes too much electrical power to provide a practical
solution for the home wet floor cleaning market.
[0016] Recently, improvements in conventional manual wet floor
cleaning in the home are disclosed in U.S. Pat. No. 5,968,281 by
Wright et al., and assigned to Royal Appliance Mfg., entitled
METHOD FOR MOPPING AND DRYING A FLOOR. Disclosed therein is a low
cost wet mopping system for manual use in the home market. The wet
mopping system disclosed by Wright et al. comprises a manual floor
cleaning device having a handle with a cleaning fluid supply
container supported on the handle. The device includes a cleaning
fluid dispensing nozzle supported on the handle for spraying
cleaning fluid onto the floor and a floor scrubber sponge attached
to the end of the handle for contact with the floor. The device
also includes a mechanical device for wringing waste liquid out of
the scrubbing sponge. A squeegee and an associated suction device
are supported on the end of the handle and used to collect waste
liquid up from the floor surface and deposit the waste liquid into
a waste liquid container, supported on the handle separate from the
cleaning solution reservoir. The device also includes a battery
power source for powering the suction device. While Wright et al.
teach a self contained wet cleaning device as well as an improved
wet cleaning method that separates waste liquid from cleaning fluid
the device is manually operated and lacks robotic
functionality.
BRIEF SUMMARY OF THE INVENTION
[0017] The present invention overcomes the problems cited in the
prior by providing low cost autonomous robot capable of wet
cleaning floors and affordable for home use. The problems of the
prior art are addressed by the present invention which provides an
autonomous cleaning robot comprising a chassis and a transport
drive system configured to autonomously transport cleaning elements
over a cleaning surface. The robot is supported on the cleaning
surface by wheels in rolling contact with the cleaning surface and
the robot includes controls and drive elements configured to
control the robot to generally traverse the cleaning surface in a
forward direction defined by a fore-aft axis. The robot is further
defined by a transverse axis perpendicular to the fore-aft
axis.
[0018] The robot chassis carries a first cleaning zone A comprising
cleaning elements arranged to collect loose particulates from the
cleaning surface across a cleaning width. The cleaning elements of
the first cleaning zone utilize a jet port disposed on a transverse
edge of the robot and configured to blow a jet of air across a
cleaning width of the robot towards the opposite transverse edge. A
vacuum intake port is disposed on the robot opposed to the jet port
to suction up loose particulates blown across the cleaning width by
the jet port.
[0019] The robot chassis may also carries a second cleaning zone B
comprising cleaning elements arraigned to apply a cleaning fluid
onto the surface. The second cleaning zone also includes cleaning
elements configure to collect the cleaning fluid up from the
surface after it has been used to clean the surface and may further
include elements for scrubbing the cleaning surface and for
smearing the cleaning fluid more uniformly over the cleaning
surface.
[0020] The robot includes a motive drive subsystem controlled by a
master control module and powered by a self-contained power module
for performing autonomous movement over the cleaning surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The features of the present invention will best be
understood from a detailed description of the invention and a
preferred embodiment thereof selected for the purposes of
illustration and shown in the accompanying drawings in which:
[0022] FIG. 1 depicts an isometric view of a top surface of an
autonomous cleaning robot according to the present invention.
[0023] FIG. 2 depicts an isometric view of a bottom surface of a
chassis of an autonomous cleaning robot according to the present
invention.
[0024] FIG. 3 depicts an isometric view of a top surface of a robot
chassis having robot subsystems attached thereto according to the
present invention.
[0025] FIG. 4 depicts a block diagram showing the interrelationship
of subsystems of an autonomous cleaning robot according to the
present invention.
[0026] FIG. 5 depicts a schematic representation of a liquid
applicator assembly according to the present invention.
[0027] FIG. 6 depicts a section view taken through a stop valve
assembly installed within a cleaning fluid supply tank according to
the present invention.
[0028] FIG. 7 depicts a section view taken through a pump assembly
according to the present invention.
[0029] FIG. 8 depicts a top view of a flexible element used as a
diaphragm pump according to the present invention.
[0030] FIG. 9 depicts a top view of a nonflexible chamber element
used in the pump assembly according to the present invention.
[0031] FIG. 10 depicts an exploded isometric view of a scrubbing
module according to the present invention.
[0032] FIG. 11 depicts a rotatable scrubbing brush according to the
present invention.
[0033] FIG. 12 depicts a section view taken through a second
collecting apparatus used for collecting waste liquid according to
the present invention.
[0034] FIG. 13 is a block diagram showing elements of a drive
module used to rotate the scrubbing brush according to the present
invention.
[0035] FIG. 14 is a schematic representation of an air moving
system according to the present invention.
[0036] FIG. 15 depicts a fan assembly according to the present
invention.
[0037] FIG. 16 depicts an exploded isometric view showing elements
of an integrated liquid storage module according to the present
invention.
[0038] FIG. 17 depicts an external view of the integrated liquid
storage module removed from the cleaning robot according to the
present invention.
[0039] FIG. 18 depicts an exploded view of a nose wheel module
according to the present invention.
[0040] FIG. 19 depicts a section view taken through a nose wheel
assembly according to the present invention.
[0041] FIG. 20 depicts an exploded view of a drive wheel assembly
according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0042] Referring now to the drawings where like reference numerals
identify corresponding or similar elements throughout the several
views, FIG. 1 depicts an isometric view showing the external
surfaces of an autonomous cleaning robot 100 according to a
preferred embodiment of the present invention. The robot 100 is
configured with a cylindrical volume having a generally circular
cross-section 102 with a top surface and a bottom surface that is
substantially parallel and opposed to the top surface. The circular
cross-section 102 is defined by three mutually perpendicular axes;
a central vertical axis 104, a fore-aft axis 106, and a transverse
axis 108. The robot 100 is movably supported with respect to a
surface to be cleaned, hereinafter, the cleaning surface. The
cleaning surface is substantially horizontal. The robot 100 is
generally supported in rolling contact with the cleaning surface by
a plurality of wheels or other rolling elements attached to a
chassis 200. In the preferred embodiment, the fore-aft axis 108
defines a transport axis along which the robot is advanced over the
cleaning surface. The robot is preferably advanced in a forward or
fore travel direction, designated F, during cleaning operations.
The opposite travel direction, (i.e. opposed by 180.degree.), is
designated A for aft. The robot is preferably not advanced in the
aft direction during cleaning operations but may be advanced in the
aft direction to avoid an object or maneuver out of a corner or the
like. Cleaning operations may continue or be suspended during aft
transport. The transverse axis 108 is further defined by the labels
R for right and L for left, as viewed from the top view of FIG. 1.
In subsequent figures, the R and L direction remain consistent with
the top view, but may be reversed on the printed page. In the
preferred embodiment of the present invention, the diameter of the
robot circular cross-section 102 is approximately 370 mm, (14.57
inches) and the height of the robot 100 above the cleaning surface
of approximately 85 mm, (3.3 inches). However, the autonomous
cleaning robot 100 of the present invention may be built with other
cross-sectional diameter and height dimensions, as well as with
other cross-sectional shapes, e.g. square, rectangular and
triangular, and volumetric shapes, e.g. cube, bar, and
pyramidal.
[0043] The robot 100 may include a user input control panel, not
shown, disposed on an external surface, e.g. the top surface, with
one or more user manipulated actuators disposed on the control
panel. Actuation of a control panel actuator by a user generates an
electrical signal, which is interpreted to initiate a command. The
control panel may also include one or more mode status indicators
such as visual or audio indicators perceptible by a user. In one
example, a user may set the robot onto the cleaning surface and
actuate a control panel actuator to start a cleaning operation. In
another example, a user may actuate a control panel actuator to
stop a cleaning operation.
[0044] Referring now to FIG. 2, the autonomous robot 100 includes a
plurality of cleaning modules supported on a chassis 200 for
cleaning the substantially horizontal cleaning surface as the robot
is transported over the cleaning surface. The cleaning modules
extend below the robot chassis 200 to contact or otherwise operate
on the cleaning surface during cleaning operations. More
specifically, the robot 100 is configured with a first cleaning
zone A for collecting loose particulates from the cleaning surface
and for storing the loose particulates in a receptacle carried by
the robot. The robot 100 is further configured with a second
cleaning zone B that at least applies a cleaning fluid onto the
cleaning surface. The cleaning fluid may be clean water alone or
clean water mixed with other ingredients to enhance cleaning. The
application of the cleaning fluid serves to dissolve, emulsify or
otherwise react with contaminates on the cleaning surface to
separate contaminates therefrom. Contaminates may become suspended
or otherwise combined with the cleaning fluid. After the cleaning
fluid has been applied onto the surface, it mixes with contaminates
and becomes waste material, e.g. a liquid waste material with
contaminates suspended or otherwise contained therein.
[0045] The underside of the robot 100 is shown in FIG. 2 which
depicts a first cleaning zone A disposed forward of the second
cleaning zone B with respect to the fore-aft axis 106. Accordingly,
the first cleaning zone A precedes the second cleaning zone B over
the cleaning surface when the robot 100 travels in the forward
direction. The first and second cleaning zones are configured with
a cleaning width W that is generally oriented parallel or nearly
parallel with the transverse axis 108. The cleaning width W defines
the cleaning width or cleaning footprint of the robot. As the robot
100 advances over the cleaning surface in the forward direction,
the cleaning width is the width of cleaning surface cleaned by the
robot in a single pass. Ideally, the cleaning width extends across
the full transverse width of the robot 100 to optimize cleaning
efficiency; however, in a practical implementation, the cleaning
width is narrower that the robot transverse width due to spatial
constraints on the robot chassis 200.
[0046] According to the present invention, the robot 100 traverses
the cleaning surface in a forward direction over a cleaning path
with both cleaning zones operating simultaneously. In the preferred
embodiment, the nominal forward velocity of the robot is
approximately 4.75 inches per second however; the robot and
cleaning devices may be configured to clean at faster and slower
forward velocities. The first cleaning zone A precedes the second
cleaning zone B over the cleaning surface and collects loose
particulates from the cleaning surface across the cleaning width W.
The second cleaning zone B applies cleaning fluid onto the cleaning
surface across the cleaning width W. The second cleaning zone may
also be configured to smear the cleaning fluid applied onto the
cleaning surface to smooth the cleaning fluid into a more uniform
layer and to mix the cleaning fluid with contaminates on the
cleaning surface. The second cleaning zone B may also be configured
to scrub the cleaning surface across the cleaning width. The
scrubbing action agitates the cleaning fluid to mix it with
contaminates. The scrubbing action also applies a friction force
against contaminates to thereby dislodge contaminates from the
cleaning surface. The second cleaning zone B may also be configured
to collect waste liquid from cleaning surface across the cleaning
width. According to the invention, a single pass of the robot over
a cleaning path first collects loose particulates up from the
cleaning surface across the cleaning width and thereafter applies a
cleaning fluid onto the cleaning surface generally across the
cleaning width W to interact with contaminates remaining on the
cleaning surface and may further apply a scrubbing action to
dislodge contaminates from the cleaning surface. A single pass of
the robot 100 over a cleaning path may also smear the cleaning
fluid more uniformly on the cleaning surface. A single pass of the
robot over a cleaning path may also collect waste liquid up from
the cleaning surface.
[0047] In general, the cleaning robot 100 is configured to clean
uncarpeted indoor hard floor surface, e.g. floors covered with
tiles, wood, vinyl, linoleum, smooth stone or concrete and other
manufactured floor covering layers that are not overly abrasive and
that do not readily absorb liquid. In addition, in the preferred
embodiment of the present invention, the robot 100 is configured to
autonomously transport over the floors of small enclosed furnished
rooms such as are typical of residential homes and smaller
commercial establishments. The robot 100 does not operate over
predefined cleaning paths but instead, moves over substantially all
of the cleaning surface area under the control of various transport
algorithms designed to operate irrespective of the enclosure shape
or obstacle distribution. In particular, the robot 100 of the
present invention moves over cleaning paths in accordance with
preprogrammed procedures implemented in hardware, software,
firmware, or combinations thereof to implement three basic
operational modes, i.e., movement patterns, that can be categorized
as: (1) a "spot-coverage" mode; (2) a "wall/obstacle following"
mode; and (3) a "bounce" mode. In addition, the robot 100 is
preprogrammed to initiate actions based upon signals received from
sensors incorporated therein, where such actions include, but are
not limited to, implementing one of the movement patterns above, an
emergency stop of the robot 100, or issuing an audible alert. These
operational modes of the robot of the present invention are
specifically described in commonly-owned U.S. Pat. No. 6,809,490,
by Jones et al., entitled, METHOD AND SYSTEM FOR MULTI-MODE
COVERAGE FOR AN AUTONOMOUS ROBOT, the entire content of which is
hereby incorporated herein by reference.
[0048] In a preferred embodiment, the robot 100 is configured to
clean approximately 150 square feet of cleaning surface in a single
cleaning operation. The duration of the cleaning operation is
approximately 45 minutes. Accordingly, the robot systems are
configured for unattended autonomous cleaning for 45 minutes or
more without the need to recharge a power supply, refill the supply
of cleaning fluid or empty the waste materials collected by the
robot.
[0049] As shown in FIG. 2 and 3 the robot 100 includes a plurality
of subsystems mounted to a robot chassis 200. The major robot
subsystems are shown schematically in FIG. 4 which depicts a master
control module 300 interconnected for two-way communication with
each of a plurality of other robot subsystems. The interconnection
of the robot subsystems is provided via network of interconnected
wires and or conductive elements, e.g. conductive paths formed on
an integrated printed circuit board or the like, as is well known.
The master control module 300 at least includes a programmable or
preprogrammed digital data processor, e.g. a microprocessor, for
performing program steps, algorithms and or mathematical and
logical operations as may be required. The master control module
300 also includes a digital data memory in communication with the
data processor for storing program steps and other digital data
therein. The master control module 300 also includes one or more
clock elements for generating timing signals as may be
required.
[0050] A power module 310 delivers electrical power to all of the
major robot subsystems. The power module includes a self-contained
power source attached to the robot chassis 200, e.g. a rechargeable
battery, such as a conventional nickel metal hydride battery, or
the like. In addition, the power source is configured to be
recharged by any one of various recharging elements and or
recharging modes, or the battery may be replaced by a user when it
becomes discharged or unusable. The master control module 300 may
also interface with the power module 310 to control the
distribution of power, to monitor power use and to initiate power
conservation modes as required.
[0051] The robot 100 may also include one or more interface modules
or elements 320. Each interface module 320 is attached to the robot
chassis to provide an interconnecting element or port for
interconnecting with one or more external devices. Interconnecting
elements and ports are preferably accessible on an external surface
of the robot. The master control module 300 may also interface with
the interface modules 320 to control the interaction of the robot
100 with external device. In particular, one interface module
element is provided for charging the rechargeable battery via an
external power supply or power source such as a conventional AC or
DC power outlet. Another interface module element may be configured
for one or two way communications over a wireless network and
further interface module elements may be configure to interface
with one or more mechanical devices to exchange liquids and loose
particulates therewith, e.g. for filling a cleaning fluid reservoir
or for draining or emptying a waste material container.
[0052] Accordingly, the interface module 320 may comprise a
plurality of interface ports and connecting elements for
interfacing with active external elements for exchanging operating
commands, digital data and other electrical signals therewith. The
interface module 320 may further interface with one or more
mechanical devices for exchanging liquid and or solid materials
therewith. The interface module 320 may also interface with an
external power supply for charging the robot power module 310.
Active external devices for interfacing with the robot 100 may
include, but are not limited to, a floor standing docking station,
a hand held remote control device, a local or remote computer, a
modem, a portable memory device for exchanging code and or data
with the robot and a network interface for interfacing the robot
100 with any device connected to the network. In addition, the
interface module 320 may include passive elements such as hooks and
or latching mechanisms for attaching the robot 100 to a wall for
storage or for attaching the robot to a carrying case or the
like.
[0053] In particular, an active external device according to one
aspect of the present invention confines the robot 100 in a
cleaning space such as a room by emitting radiation in a virtual
wall pattern. The robot 100 is configured to detect the virtual
wall pattern and is programmed to treat the virtual wall pattern as
a room wall so that the robot does not pass through the virtual
wall pattern. This particular aspect of the present invention is
specifically described in commonly-owned, U.S. Pat. No. 6,690,134
by Jones et al., entitled METHOD AND SYSTEM FOR ROBOT LOCALIZATION
AND CONFINEMENT, the entire content of which is hereby incorporated
herein by reference.
[0054] Another active external device according to a further aspect
of the present invention comprises a robot base station used to
interface with the robot. The base station may comprise a fixed
unit connected with a household power supply, e.g. and AC power
wall outlet and or other household facilities such as a water
supply pipe, a waste drain pipe and a network interface. According
to invention, the robot 1 00 and the base station are each
configured for autonomous docking and the base station may be
further configure to charge the robot power module 3 1 0 and to
service the robot in other ways. A base station and autonomous
robot configured for autonomous docking and for recharging the
robot power module is specifically described in commonly-owned and
co-pending U.S. patent application Ser. No. 10/762,219, filed on
Jan. 21, 2004, entitled AUTONOMOUS ROBOT AUTO-DOCKING AND ENERGY
MANAGEMENT SYSTEMS AND METHOD, the entire content of which is
hereby incorporated herein by reference.
[0055] The autonomous robot 100 includes a self-contained motive
transport drive subsystem 900 which is further detailed below. The
transport drive 900 includes three wheels extending below the
chassis 200 to provide three points of rolling support with respect
to the cleaning surface. A nose wheel is attached to the robot
chassis 200 at a forward edge thereof, coaxial with the fore-aft
axis 106, and a pair of drive wheels attached to the chassis 200
aft of the transverse axis 108 and rotatable about a drive axis
that is parallel with the transverse axis 108. Each drive wheel is
separately driven and controlled to advance the robot in a desired
direction. In addition, each drive wheel is configured to provide
sufficient drive friction as the robot operates on a cleaning
surface that is wet with cleaning fluid. The nose wheel is
configured to self align with the direction of travel. The drive
wheels may be controlled to move the robot 100 forward or aft in a
straight line or along an arcuate path.
[0056] The robot 100 further includes a sensor module 340. The
sensor module 340 comprises a plurality of sensors attached to the
chassis and or integrated with robot subsystems for sensing
external conditions and for sensing internal conditions. In
response to sensing various conditions, the sensor module 340 may
generate electrical signals and communicate the electrical signals
to the control module 300. Individual sensors may perform such
functions as detecting walls and other obstacles, detecting drop
offs in the cleaning surface, called cliffs, detecting dirt on the
floor, detecting low battery power, detecting an empty cleaning
fluid container, detecting a full waste container, measuring or
detecting drive wheel velocity distance traveled or slippage,
detecting nose wheel rotation or cliff drop off, detecting cleaning
system problems such rotating brush stalls or vacuum system clogs,
detecting inefficient cleaning, cleaning surface type, system
status, temperature, and many other conditions. In particular,
several aspects of the sensor module 340 of the present invention
as well as and its operation, especially as it relates to sensing
external elements and conditions are specifically described in
commonly-owned, U.S. Pat. No. 6,594,844, by Jones, entitled ROBOT
OBSTACLE DETECTION SYSTEM, the entire content of which is hereby
incorporated herein by reference.
[0057] The robot 100 may also include a user control module 330.
The user control module 330 provides one or more user input
interfaces that generate an electrical signal in response to a user
input and communicate the signal to the master control module 300.
In one embodiment of the present invention, the user control
module, described above, provides a user input interface, however,
a user may enter commands via a hand held remote control device, a
programmable computer or other programmable device or via voice
commands. A user may input user commands to initiate actions such
as power on/off, start, stop or to change a cleaning mode, set a
cleaning duration, program cleaning parameters such as start time
and duration, and or many other user initiated commands.
Cleaning Zones
[0058] Referring now to FIG. 2, a bottom surface of a robot chassis
200 is shown in isometric view. As shown therein, a first cleaning
zone A is disposed forward of a second cleaning zone B with respect
to the fore-aft axis 106. Accordingly, as the robot 100 is
transported in the forward direction the first cleaning zone A
precedes the second cleaning zone B over the cleaning surface. Each
cleaning zone A and B has a cleaning width W disposed generally
parallel with the transverse axis 108. Ideally, the cleaning width
of each cleaning zone is substantially identical however, the
actual cleaning width of the cleaning zones A and B may be slightly
different. According to the preferred embodiment of the present
invention, the cleaning width W is primarily defined by the second
cleaning zone B which extends from proximate to the right
circumferential edge of a bottom surface of the robot chassis 200
substantially parallel with the transverse axis 108 and is
approximately 296 mm (11.7 inches) long. By locating the cleaning
zone B proximate the right circumferential edge, the robot 100 may
maneuver its right circumferential edge close to a wall or other
obstacle for cleaning the cleaning surface adjacent to the wall or
obstacle. Accordingly, the robot movement patterns include
algorithms for transporting the right side of the robot 100
adjacent to each wall or obstacle encountered by the robot during a
cleaning cycle. The robot 100 is therefore said to have a dominant
right side. Of course, the robot 100 could be configured with a
dominant left side instead. The first cleaning zone A is positioned
forward of the transverse axis 108 and has a slightly narrower
cleaning width than the second cleaning zone B, simply because of
the circumference shape of the robot 100. However, any cleaning
surface area not cleaned by the first cleaning zone A is cleaned by
the second cleaning zone B.
First Cleaning Zone
[0059] The first cleaning zone A is configured to collect loose
particulates from the cleaning surface. In the preferred
embodiment, an air jet is generated by an air moving system which
includes an air jet port 554 disposed on a left edge of the first
cleaning zone A. The air jet port 554 expels a continuous jet or
stream of pressurized air therefrom. The air jet port 554 is
oriented to direct the air jet across the cleaning width from left
to right. Opposed to the air jet port 554, an air intake port 556
is disposed on a right edge of the first cleaning zone A. The air
moving system generates a negative air pressure zone in the
conduits connected to the intake port 556, which creates a negative
air pressure zone proximate to the intake port 556. The negative
air pressure zone suctions loose particulates and air into the air
intake port 556 and the air moving system is further configured to
deposit the loose particulates into a waste material container
carried by the robot 100. Accordingly, pressurized air expelled
from the air jet port 554 moves across the cleaning width within
the first cleaning zone A and forces loose particulates on the
cleaning surface toward a negative air pressure zone proximate to
the air intake port 556. The loose particulates are suctioned up
from the cleaning surface through the air intake port 556 and
deposited into a waste container carried by the robot 100.
[0060] The first cleaning zone A is further defined by a nearly
rectangular channel formed between the air jet port 554 and the air
intake port 556. The channel is defined by opposing forward and aft
walls of a rectangular recessed area 574, which is a contoured
shape formed in the bottom surface of the robot chassis 200. The
forward and aft walls a substantially transverse to the fore-aft
axis 106. The channel is further defined by a first compliant
doctor blade 576, attached to the robot chassis 200, e.g. along the
aft edge of the recessed area 574, and extending from the chassis
bottom surface to the cleaning surface. The doctor blade is mounted
to make contact or near contact with the cleaning surface. The
doctor blade 576 is preferably formed from a thin flexible and
compliant molded material e.g. a 1-2 mm thick bar shaped element
molded from neoprene rubber or the like. The doctor blade 576, or
at least a portion of the doctor blade, may be coated with a low
friction material, e.g. a fluoropolymer resin for reducing friction
between the doctor blade and the cleaning surface. The doctor blade
576 may be attached to the robot chassis 200 by an adhesive bond or
by other suitable means.
[0061] The channel of the first cleaning zone A provides an
increased volume between the cleaning surface and the bottom
surface of the robot chassis 200 local to the first cleaning zone
A. The increased volume guides airflow between the jet port 554 and
the air intake port 556, and the doctor blade 576 prevents loose
particulates and airflow from escaping the first cleaning zone A in
the aft direction. In addition to guiding the air jet and the loose
particulates across the cleaning width, the first doctor blade 576
may also exert a friction force against contaminates on the
cleaning surface to help loosen contaminates from the cleaning
surface as the robot moves in the forward direction. The first
compliant doctor blade 576 is configured to be sufficiently
compliant to adapt its profile form conforming to discontinuities
in the cleaning surface, such a door jams moldings and trim pieces,
without hindering the forward travel of the robot 100.
[0062] A second compliant doctor blade 578 may also be disposed in
the first cleaning zone A to further guide the air jet toward the
negative pressure zone surrounding the air intake port 554. The
second compliant doctor blade is similar in construction to the
first compliant doctor blade 576 and attaches to the bottom surface
of the robot chassis 200 to further guide the air and loose
particulates moving through the channel. In one example, a second
recessed area 579 is formed in the bottom surface of the chassis
200 and the second compliant doctor blade 576 protrudes into the
first recessed area 574 at an acute angle typically between
30-60.degree. with respect to the traverse axis 108. The second
compliant doctor blade extends from the forward edge of the
recessed area 574 and protrudes into the channel approximately 1/3
to 1/2 of channel fore-aft dimension.
[0063] The first cleaning zone A traverses the cleaning surface
along a cleaning path and collects loose particulates along the
cleaning width. By collecting the loose particulates prior to the
second cleaning zone B passing over the cleaning path, the loose
particulates are collected before the second cleaning zone applies
cleaning fluid onto the cleaning surface. One advantage of removing
the loose particulates with the first cleaning zone is that the
loose particulates are removed while they are still dry. Once the
loose particulates absorb cleaning fluid applied by the second
cleaning zone, they are more difficult to collect. Moreover, the
cleaning fluid absorbed by the loose particulates is not available
for cleaning the surface so the cleaning efficiency of the second
cleaning zone B may be degraded.
[0064] In another embodiment, the first cleaning zone may be
configured with other cleaning elements such as counter-rotating
brushes extending across the cleaning width to flick loose
particulates into a receptacle. In another embodiment, an air
moving system may be configured to draw air and loose particulates
up from the cleaning surface through an elongated air intake port
extending across the cleaning width. In particular, other
embodiments usable to provide a first cleaning zone according to
the present invention are disclosed in commonly-owned U.S. Pat. No.
6,883,201, by Jones et al. entitled AUTONOMOUS FLOOR-CLEANING
ROBOT, the entire content of which is hereby incorporated herein by
reference.
Second Cleaning Zone
[0065] The second cleaning zone B includes a liquid applicator 700
configured to apply a cleaning fluid onto the cleaning surface and
the cleaning fluid is preferably applied uniformly across the
entire cleaning width. The liquid applicator 700 is attached to the
chassis 200 and includes at least one nozzle configured to spray
the cleaning fluid onto the cleaning surface. The second cleaning
zone B may also include a scrubbing module 600 for performing other
cleaning tasks across the cleaning width after the cleaning fluid
has been applied onto the cleaning surface. The scrubbing module
600 may include a smearing element disposed across the cleaning
width for smearing the cleaning fluid to distribute it more
uniformly on the cleaning surface. The second cleaning zone B may
also include a passive or active scrubbing element configured to
scrub the cleaning surface across the cleaning width. The second
cleaning zone B may also include a second collecting apparatus
configured to collect waste materials up from the cleaning surface
across the cleaning width, and the second collecting apparatus is
especially configured for collecting liquid waste materials.
Liquid Applicator Module
[0066] The liquid applicator module 700, shown schematically in
FIG. 5, is configured to apply a measured volume of cleaning fluid
onto the cleaning surface across the cleaning width. The liquid
applicator module 700 receives a supply of cleaning fluid from a
cleaning fluid supply container S, carried on the chassis 200, and
pumps the cleaning fluid through one or more spray nozzles disposed
on the chassis 200. The spray nozzles are attached to the robot
chassis 200 aft of the first cleaning zone A and each nozzle is
oriented to apply cleaning fluid onto the cleaning surface. In the
preferred embodiment, a pair of spray nozzle are attached to the
robot chassis 200 at distal left and right edges of the cleaning
width W. Each nozzle is oriented to spray cleaning fluid toward the
opposing end of the cleaning width. Each nozzles is separately
pumped to eject a spray pattern and the pumping stroke of each
nozzle occurs approximately 180 degrees out phase with respect to
the other nozzle so that one of the two nozzles is always applying
cleaning fluid.
[0067] Referring to FIG. 5, the liquid applicator module 700
includes a cleaning fluid supply container S, which is carried by
the chassis 200 and removable therefrom by a user to refill the
container with cleaning fluid. The supply container S is configured
with a drain or exit aperture 702 formed through a base surface
thereof. A fluid conduit 704 receives cleaning fluid from the exit
aperture 702 and delivers a supply of cleaning fluid to a pump
assembly 706. The pump assembly 706 includes left and right pump
portions 708 and 710, driven by a rotating cam, shown in FIG. 7.
The left pump portion 708 pumps cleaning fluid to a left spray
nozzle 712 via a conduit 716 and the right pump portion 710 pumps
cleaning fluid to a right spray nozzle 714 via a conduit 718.
[0068] A stop valve assembly, shown in section view in FIG. 6,
includes a female upper portion 720, installed inside the supply
container S, and a male portion 721 attached to the chassis 200.
The female portion 720 nominally closes and seals the exit aperture
702. The male portion 721 opens the exit aperture 702 to provide
access to the cleaning fluid inside the supply container S. The
female portion 720 includes an upper housing 722, a spring biased
movable stop 724, a compression spring 726 for biasing the stop 724
to a closed position, and a gasket 728 for sealing the exit
aperture 702. The upper housing 722 may also support a filter
element 730 inside the supply container S for filtering
contaminates from the cleaning fluid before the fluid exits the
supply container S.
[0069] The stop valve assembly male portion 721 includes a hollow
male fitting 732 formed to insert into the exit aperture 702 and
penetrate the gasket 728. Insertion of the hollow male fitting 732
into the exit aperture 702 forces the movable stop 724 upward
against the compression spring 726 to open the stop valve. The
hollow male fitting 732 is formed with a flow tube 734 along it
central longitudinal axis and the flow tube 734 includes one or
more openings 735 at its uppermost end for receiving cleaning fluid
into the flow tube 734. At its lower end, the flow tube 734 is in
fluid communication with a hose fitting 736 attached to or
integrally formed with the male fitting 732. The hose fitting 736
comprises a tube element having a hollow fluid passage 737 passing
therethrough, and attaches to hose or fluid conduit 704 that
receives fluid from the hose fitting 736 and delivers the fluid to
the pump assembly 706. The flow tube 734 may also include a user
removable filter element 739 installed therein for filtering the
cleaning fluid as it exits the supply container S.
[0070] According to the invention, the stop valve male portion 721
is fixed to the chassis 200 and engages with the female portion
720, which is fixed to the container S. When the container S is
installed onto the chassis in its operating position the male
portion 721 engages with the female portion 720 to open the exit
aperture 702. A supply of cleaning fluid flows from the supply
container S to the pump assembly 706 and the flow may be assisted
by gravity or suctioned by the pump assembly or both.
[0071] The hose fitting 736 is further equipped with a pair of
electrically conductive elements, not shown, disposed on the
internal surface of the hose fitting fluid flow passage 737 and the
pair of conductive elements inside the flow chamber are
electrically isolated from each other. A measurement circuit, not
shown, creates an electrical potential difference between the pair
of electrically conductive elements and when cleaning fluid is
present inside the flow passage 737 current flows from one
electrode to the other through the cleaning fluid and the
measurement circuit senses the current flow. When the container S
is empty, the measurement circuit fails to sense the current flow
and in response sends a supply container empty signal to the master
controller 300. In response to receiving the supply container empty
signal, the master controller 300 takes an appropriate action.
[0072] The pump assembly 706 as depicted in FIG. 5 includes a left
pump portion 708 and a right pump portion 710. The pump assembly
706 receives a continuous flow of cleaning fluid from the supply
container S and alternately delivers cleaning fluid to the left
nozzle 712 and the right nozzle 714. FIG. 7 depicts the pump
assembly 706 in section view and the pump assembly 706 is shown
mounted on the top surface of the chassis 200 in FIG. 3. The pump
assembly 706 includes cam element 738 mounted on a motor drive
shaft for rotation about a rotation axis. The motor, not shown, is
rotates the cam element 738 at a substantially constant angular
velocity under the control of the master controller 300. However,
the angular velocity of the cam element 738 may be increased or
decreased to vary the frequency of pumping of the left and right
spay nozzles 712 and 714. In particular, the angular velocity of
the cam element 738 controls the mass flow rate of cleaning fluid
applied onto the cleanings surface. According to one aspect of the
present invention, the angular velocity of the cam element 738 may
be adjusted in proportion to the robot forward velocity to apply a
uniform volume of cleaning fluid onto the cleaning surface
irrespective of robot velocity. Alternately, changes in the angular
velocity in the cam element 738 may be used to increase or decrease
the mass flow rate of cleaning fluid applied onto the cleanings
surface as desired.
[0073] The pump assembly 706 includes a rocker element 761 mounted
to pivot about a pivot axis 762. The rocker element 761 includes a
pair of opposed cam follower elements 764 on the left side and 766
on the right side. Each cam follower 764 and 766 remains in
constant contact with a circumferential profile of the cam element
738 as the cam element rotates about its rotation axis. The rocker
element 761 further includes a left pump actuator link 763 and a
right pump actuator link 765. Each pump actuator link 763 and 765
is fixedly attached to a corresponding left pump chamber actuator
nipple 759 and a right pump chamber actuator nipple 758. As will be
readily understood, rotation of the cam element 738 forces each of
the cam follower elements 764 and 766 to follow the cam
circumferential profile and the motion dictated by the cam profile
is transferred by the rocker element 761 to each of the left and
right actuator nipples 759 and 758. As described below, the motion
of the actuator nipples is used to pump cleaning fluid. The cam
profile is particularly shaped to cause the rocker element 761 to
force the right actuator nipple 758 downward while simultaneously
lifting up on the left actuator nipple 759, and this action occurs
during the first 180 degrees of cam. Alternately, the second 180
degrees of cam rotation causes the rocker element 761 to force the
left actuator nipple 759 downward while simultaneously lifting up
on the right actuator nipple 758.
[0074] The rocker element 761 further includes a sensor arm 767
supporting a permanent magnet 769 attached at its end. A magnetic
field generated by the magnet 769 interacts with an electrical
circuit 771 supported proximate to the magnet 769 and the circuit
generates signals responsive to changes in the orientation of
magnetic field. the signals are used to track the operation of the
pump assembly 706.
[0075] Referring to FIGS. 7-9, the pump assembly 706 further
comprises a flexible membrane 744 mounted between opposing upper
and lower nonflexible elements 746 and 748 respectively. Referring
to the section view in FIG. 7 the flexible element 744 is captured
between an upper nonflexible element 746 and a lower nonflexible
element 748. Each of the upper nonflexible element 746, the
flexible element 744 and the lower nonflexible element 748 is
formed as a substantially rectangular sheet having a generally
uniform thickness. However, each element also includes patterns of
raised ridges depressed valleys and other surface contours formed
on opposing surfaces thereof. FIG. 8 depicts a top view of the
flexible element 744 and FIG. 9 depicts a top view of the lower
nonflexible element 748. The flexible element 744 is formed from a
flexible membrane material such as neoprene rubber or the like and
the nonflexible elements 748 and 746 are each formed from a stiff
material nonflexible such as moldable hard plastic or the like.
[0076] As shown in FIGS. 8 and 9, each of the flexible element 744
and the nonflexible element 748 are symmetrical about a center axis
designated E in the figure. In particular, the left sides of each
of the elements 746, 744 and 748 combine to form a left pump
portion and the rights side of each of the elements 746, 744 and
748 combine to form a right pump portion. The left and right pump
portions are substantially identical. When the three elements are
assembled together, the raised ridges, depressed valleys and
surface contours of each element cooperate with raised ridges
depressed valleys and surface contours of the contacting surfaces
of other of the elements to create fluid wells and passageways. The
wells and passageways may be formed between the upper element 746
and the flexible element 744 or between the lower nonflexible
element 748 and the flexible element 744. In general, the flexible
element 744 serves as a gasket layer for sealing the wells and
passages and its flexibility is used to react to changes in
pressure to seal and or open passages in response to local pressure
changes as the pump operates. In addition, holes formed through the
elements allow fluid to flow in and out of the pump assembly and to
flow through the flexible element 744.
[0077] Using the right pump portion by way of example, cleaning
fluid is drawn into the pump assembly through an aperture 765
formed in the center of the lower nonflexible element 748. The
aperture 765 receives cleaning fluid from the fluid supply
container via the conduit 704. The incoming fluid fills a
passageway 766. Ridges 775 and 768 form a valley between them and a
mating raised ridge on the flexible 744 fills the valley between
the ridges 775 and 768. This confines the fluid within the
passageway 766 and pressure seal the passageway. An aperture 774
passes through the flexible element 744 and is in fluid
communication with the passageway 766. When the pump chamber,
described below, expands, the expansion decreases the local
pressure, which draws fluid into the passageway 776 through the
aperture 774.
[0078] Fluid drawn through the aperture 774 fills a well 772. The
well 772 is formed between the flexible element 744 and the upper
nonflexible element 746. A ridge 770 surrounds the well 772 and
mates with a feature of the upper flexible element 746 to contain
the fluid in the well 772 and to pressure seal the well. The
surface of the well 772 is flexible such that when the pressure
within the well 772 decreases, the base of the well is lifted to
open the aperture 774 and draw fluid through the aperture 774.
However, when the pressure within the well 772 increases, due to
contraction of the pump chamber, the aperture 774 is forced against
a raised stop surface 773 directly aligned with the aperture and
the well 772 act as a trap valve. A second aperture 776 passes
through the flexible element 744 to allow fluid to pass from the
well 772 through the flexible element 744 and into a pump chamber.
The pump chamber is formed between the flexible element 744 and the
lower nonflexible element 748.
[0079] Referring to FIG. 7, a right pump chamber 752 is shown in
section view. The chamber 752 includes a dome shaped flexure formed
by an annular loop 756. The dome shaped flexure is a surface
contour of the flexible element 744. The annular loop 756 passes
through a large aperture 760 formed through the upper nonflexible
element 746. The volume of the pump chamber is expanded when the
pump actuator 765 pulls up on the actuator nipple 758. The volume
expansion decreases pressure within the pump chamber and fluid is
drawn into the chamber from the well 772. The volume of the pump
chamber is decreased when the pump actuator 765 pushes down on the
actuator nipple 758. The decrease in volume within the chamber
increases pressure and the increased pressure expels fluid out of
the pump chamber.
[0080] The pump chamber is further defined by a well 780 formed in
the lower nonflexible element 748. The well 780 is surrounded by a
valley 784 formed in the lower nonflexible element 748, shown in
FIG. 9, and a ridge 778 formed on the flexible element 744 mates
with the valley 784 to pressure seal the pump chamber. The pump
chamber 752 further includes an exit aperture 782 formed through
the lower nonflexible element 748 and through which fluid is
expelled. The exit aperture 782 delivers fluid to the right nozzle
714 via the conduit 718. The exit aperture 782 is also opposed to a
stop surface which acts as a check valve to close the exit aperture
782 when the pump chamber is decreased.
[0081] Thus according to the present invention, cleaning fluid is
drawn from a cleaning supply container S by action of the pump
assembly 706. The pump assembly 706 comprises two separate pump
chambers for pumping cleaning fluid to two separate spray nozzles.
Each pump chamber is configure deliver cleaning fluid to a single
nozzle in response to a rapid increase in pressure inside the pump
chamber. The pressure inside the pump chamber is dictated by the
cam profile, which is formed to drive fluid to each nozzle in order
to spray a substantially uniform layer of cleaning fluid onto the
cleaning surface. In particular, the cam profile is configured to
deliver a substantially uniform volume of cleaning fluid per unit
length of cleaning width W. In generally, the liquid applicator of
the present invention is configured to apply cleaning fluid at a
volumetric rate ranging from about 0.2 to 5.0 ml per square foot,
and preferably in the range of about 0.6-2.0 ml per square foot.
However depending upon the application, the liquid applicator of
the present invention may apply any desired volumetric layer onto
the surface. In addition, the fluid applicator system of the
present invention is usable to apply other liquids onto a floor
surface such as wax, paint, disinfectant, chemical coatings, and
the like.
[0082] As is further described below, a user may remove the supply
container S from the robot chassis and fill the supply container
with a measured volume of clean water and a corresponding measured
volume of a cleaning agent. The water and cleaning agent may be
poured into the supply container S through a supply container
access aperture 168 which is capped by a removable cap 172, shown
in FIG. 17. The supply container S is configured with a liquid
volume capacity of approximately 1100 ml (37 fluid ounces) and the
desired volumes of cleaning agent and clean water may be poured
into the supply tank in a ratio appropriate for a particular
cleaning application.
Scrubbing Module
[0083] The scrubbing module 600, according to a preferred
embodiment of the present invention, is shown in exploded isometric
view in FIG. 10 and in the robot bottom view shown in FIG. 2. The
scrubbing module 600 is configured as a separate subassembly that
attaches to the chassis 200 but is removable therefrom, by a user,
for cleaning or otherwise servicing the cleaning elements thereof.
However, other arrangements can be configured without deviating
from the present invention. The scrubbing module 600 installs and
latches into place within a hollow cavity 602, formed on the bottom
side of the chassis 200. A profile of the hollow cavity 602 is
displayed on the right side of the chassis 200 in FIG. 3. The
cleaning elements of the scrubbing module 600 are positioned aft of
the liquid applicator module 700 to perform cleaning operations on
a wet cleaning surface.
[0084] In the preferred embodiment, the scrubbing module 600
includes a passive smearing brush 612 attached to a forward edge
thereof and disposed across the cleaning width. The smearing brush
612 extends downwardly from the scrubbing module 600 and is
configured to make contact or near contact with the cleaning
surface across the cleaning width. As the robot 100 is transported
in the forward direction the smearing brush 612 moves over the
pattern of cleaning fluid applied down by the liquid applicator and
smears, or more uniformly spreads the cleaning fluid over the
cleaning surface. The smearing brush 612, shown in FIGS. 2 and 10,
comprises a plurality of soft compliant smearing bristles 614 with
a first end of each bristle being captured in a holder such as
crimped metal channel, or other suitable holding element. A second
end of each smearing bristle 614 is free to bend as each bristle
makes contact with the cleaning surface. The length and diameter of
the smearing bristles 614, as well as a nominal interference
dimension that the smearing bristles makes with respect to the
cleaning surface may be varied to adjust bristle stiffness and to
thereby affect the smearing action. In a preferred embodiment of
the present invention the smearing brush 612 comprises nylon
bristles with an average bristle diameter in the range of about
0.05-0.2 mm, (0.002-0.008 inches). The nominal length of each
bristle 614 is approximately 16 mm, (0.62 inches), between the
holder and the cleaning surface and the bristles 614 are configured
with an interference dimension of approximately 0.75 mm, (0.03
inches). The smearing brush 612 may also wick up excess cleaning
fluid applied to the cleaning surface and distribute the wicked up
cleaning fluid to other locations. Of course, other smearing
elements such as flexible compliant blade member a sponge elements
or a rolling member in contact with the cleaning surface are also
usable.
[0085] The scrubbing module 600 may include a scrubbing element
e.g. 604; however, the present invention may be used without a
scrubbing element. The scrubbing element contacts the cleaning
surface during cleaning operations and agitates the cleaning fluid
to mix it with contaminates to emulsify, dissolve or otherwise
chemically react with contaminates. The scrubbing element also
generates a friction force as it moves with respect to the cleaning
surface and the friction force helps to break adhesion and other
bonds between contaminates and the cleaning surface. In addition,
the scrubbing element may be passive element or an active and may
contact the cleaning surface directly, may not contact the cleaning
surface at all or may be configured to be movable into and out of
contact with the cleaning surface.
[0086] In one embodiment according to the present invention, a
passive scrubbing element is attached to the scrubbing module 600
or other attaching point on the chassis 200 and disposed to contact
the cleaning surface across the cleaning width. A friction force is
generated between the passive scrubbing element and the cleaning
surface as the robot is transported in the forward direction. The
passive scrubbing element may comprise a plurality of scrubbing
bristles held in contact with the cleaning surface, a woven or
non-woven material, e.g. a scrubbing pad or sheet material held in
contact with the cleaning surface, or a compliant solid element
such as a sponge or other compliant porous solid foam element held
in contact with the cleaning surface. In particular, a conventional
scrubbing brush, sponge, or scrubbing pad used for scrubbing may be
fixedly attached to the robot 100 and held in contact with the
cleaning surface across the cleaning width aft of the liquid
applicator to scrub the cleaning surface as the robot 100 advances
over the cleaning surface. In addition, the passive scrubbing
element may be configured to be replaceable by a user or to be
automatically replenished, e.g. using a supply roll and a take up
roll for advancing clean scrubbing material into contact with the
cleaning surface.
[0087] In another embodiment according to the present invention,
one or more active scrubbing elements are movable with respect to
the cleaning surface and with respect to the robot chassis.
Movement of the active scrubbing elements increases the work done
between scrubbing elements and the cleaning surface. Each movable
scrubbing element is driven for movement with respect to the
chassis 200 by a drive module, also attached to the chassis 200.
Active scrubbing elements may also comprise a scrubbing pad or
sheet material held in contact with the cleaning surface, or a
compliant solid element such as a sponge or other compliant porous
solid foam element held in contact with the cleaning surface and
vibrated by a vibrating backing element. Other active scrubbing
elements may also include a plurality of scrubbing bristles, and or
any movably supported conventional scrubbing brush, sponge, or
scrubbing pad used for scrubbing or an ultra sound emitter may also
be used to generate scrubbing action. The relative motion between
active scrubbing elements and the chassis may comprise linear and
or rotary motion and the active scrubbing elements may be
configured to be replaceable or cleanable by a user.
[0088] Referring now to FIGS. 10-12 the preferred embodiment of
present invention includes an active scrubbing element. The active
scrubbing element comprises a rotatable brush assembly 604 disposed
across the cleaning width, aft of the liquid applicator nozzles
712, 714, for actively scrubbing the cleaning surface after the
cleaning fluid has been applied thereon. The rotatable brush
assembly 604 comprises a cylindrical bristle holder element 618 for
supporting scrubbing bristles 616 extending radially outward there
from. The rotatable brush assembly 604 is supported for rotation
about a rotation axis that extends substantially parallel with the
cleaning width. The scrubbing bristles 616 are long enough to
interfere with the cleaning surface during rotation such that the
scrubbing bristles 616 are bent by the contact with the cleaning
surface.
[0089] Scrubbing bristles 616 are installed in the brush assembly
in groups or clumps with each clump comprising a plurality of
bristles held by a single attaching device or holder. Clumps
locations are disposed along a longitudinal length of the bristle
holder element 618 in a pattern. The pattern places at least one
bristle clump in contact with cleaning surface across the cleaning
width during each revolution of the rotatable brush element 604.
The rotation of the brush element 604 is clockwise as viewed from
the right side such that relative motion between the scrubbing
bristles 616 and the cleaning surface tends to flick loose
contaminates and waste liquid in the aft direction. In addition,
the friction force generated by clockwise rotation of the brush
element 604 tends drive the robot in the forward direction thereby
adding to the forward driving force of the robot transport drive
system. The nominal dimension of each scrubbing bristles 616
extended from the cylindrical holder 618 causes the bristle to
interfere with the cleaning surface and there for bend as it makes
contact with the surface. The interference dimension is the length
of bristle that is in excess of the length required to make contact
with the cleaning surface. Each of these dimensions plus the
nominal diameter of the scrubbing bristles 616 may be varied to
affect bristle stiffness and therefore the resulting scrubbing
action. Applicants have found that configuring the scrubbing brush
element 604 with nylon bristles having a bend dimension of
approximately 16-40 mm, (0.62-1.6 inches), a bristle diameter of
approximately 0.15 mm, (0.006 inches) and an interference dimension
of approximately 0.75 mm, (0.03 inches) provides good scrubbing
performance. In another example, stripes of scrubbing material may
be disposed along a longitudinal length of the bristle holder
element 618 in a pattern attached thereto for rotation
therewith.
Squeegee and Wet Vacuuming
[0090] The scrubbing module 600 may also include a second
collecting apparatus configured to collect waste liquid from the
cleaning surface across the cleaning width. The second collecting
apparatus is generally positioned aft of the liquid applicator
nozzles 712, 714, aft of the smearing brush, and aft of the
scrubbing element. In the preferred embodiment according to the
present invention, a scrubbing module 600 is shown in section view
in FIG. 12. The smearing element 612 is shown attached to the
scrubbing module at its forward edge and the rotatable scrubbing
brush assembly 604 is shown mounted in the center of the scrubbing
module. Aft of the scrubbing brush assembly 604, a squeegee 630
contacts the cleaning surface across its entire cleaning width to
collect waste liquid as the robot 100 advances in the forward
direction. A vacuum system draws air in through ports in the
squeegee to suction waste liquid up from the cleaning surface. The
vacuum system deposits the waste liquid into a waste storage
container carried on the robot chassis 200.
[0091] As detailed in the section view of FIG. 12, the squeegee 630
comprises a vertical element 1002 and a horizontal element 1004.
Each of the elements 1002 and 1004 are formed from a substantially
flexible and compliant material such as neoprene rubber, silicone
or the like. A single piece squeegee construction is also usable.
In the preferred embodiment, the vertical element 1002 comprises a
more flexible durometer material and is more bendable and compliant
than the horizontal element 1004. The vertical squeegee element
1002 contacts the cleaning surface at a lower edge 1006 or along a
forward facing surface of the vertical element 1002 when the
vertical element is slightly bent toward the rear by interference
with the cleaning surface. The lower edge 1006 or forward surface
remains in contact with the cleaning surface during robot forward
motion and collects waste liquid along the forward surface. The
waste liquid pools up along the entire length of the forward
surface and lower edge 1006. The horizontal squeegee element 1004
includes spacer elements 1008 extending rear ward form its main
body 1010 and the spacer elements 1008 defined a suction channel
1012 between the vertical squeegee element 1002 and the horizontal
squeegee element 1004. The spacer elements 1008 are discreet
elements disposed along the entire cleaning width with open space
between adjacent spacer elements 1008 providing a passage for waste
liquid to be suctioned through.
[0092] A vacuum interface port 1014 is provided in the top wall of
the scrubber module 600. The vacuum port 1014 communicates with the
robot air moving system and withdraws air through the vacuum port
1014. The scrubber module 600 is configured with a sealed vacuum
chamber 1016, which extends from the vacuum port 1014 to the
suction channel 1012 and extends along the entire cleaning width.
Air drawn from the vacuum chamber 1016 reduces the air pressure at
the outlet of the suction channel 1012 and the reduced air
pressures draws in waste liquid and air from the cleaning surface.
The waste liquid drawing in through the suction channel 1012 enters
the chamber 1016 and is suctioned out of the chamber 1016 and
eventually deposited into a waste material container by the robot
air moving system. Each of the horizontal squeegee element 1010 and
the vertical squeegee element 1002 form walls of the vacuum chamber
1016 and the squeegee interfaces with the surrounding scrubbing
module elements are configured to pressure seal the chamber 1016.
In addition, the spacers 1008 are formed with sufficient stiffness
to prevent the suction channel 1012 form closing.
[0093] The squeegee vertical element 1002 includes a flexure loop
1018 formed at its mid point. The flexure loop 1018 provides a
pivot axis about which the lower end of the squeegee vertical
element can pivot when the squeegee lower edge 1006 encounters a
bump or other discontinuity in the cleaning surface. This also
allows the edge 1006 to flex as the robot changes travel direction.
When the squeegee lower edge 1006 is free of the bump or
discontinuity it returns to its normal operating position.
[0094] Referring to FIG. 10, the scrubbing module 600 is formed as
a separate subsystem that is removable from the robot chassis. The
scrubbing module 600 includes support elements comprising a molded
two-part housing formed by the lower housing element 634 and a
mating upper housing element 636. The lower and upper housing
elements are formed to house the rotatable scrubbing brush assembly
604 therein and to support it for rotation with respect to the
chassis. The lower and upper housing elements 634 and 636 are
attached together at a forward edge thereof by a hinged attaching
arrangement. Each housing element 634 and 636 includes a plurality
of interlacing hinge elements 638 for receiving a hinge rod 640
therein to form the hinged connection. Of course, other hinging
arrangements can be used. The lower and upper housing elements 634
and 636 form a longitudinal cavity for capturing the rotatable
scrubbing brush assembly 604 therein and may be opened by a user
when the scrubbing module 600 is removed from the robot 100. The
user may then remove the rotatable scrubbing brush assembly 604
from the housing to clean it replace it or to clear a jam.
[0095] The rotatable scrubbing brush assembly 604 comprises the
cylindrical bristle holder 618, which may be formed as a solid
element such as a sold shaft formed of glass-filled ABS plastic or
glass-filled nylon. Alternately the bristle holder 618 may comprise
a molded shaft with a core support shaft 642 inserted through a
longitudinal bore formed through the molded shaft. The core support
shaft 642 may be installed by a press fit or other appropriate
attaching means for fixedly attaching the bristle holder 618 and
the core support shaft 642 together. The core support shaft 642 is
provided to stiffen the brush assembly 604 and is therefore formed
from a stiff material such as a stainless steel rod with a diameter
of approximately 10-15 mm, (0.4-0.6 inches). The core support shaft
642 is formed with sufficient stiffness to prevent excessive
bending of the cylindrical brush holder. In addition, the core
support shaft 642 may be configured to resist corrosion and or
abrasion during normal use.
[0096] The bristle holder 618 is configured with a plurality of
bristle receiving holes 620 bored or otherwise formed perpendicular
with the rotation axis of the scrubbing brush assembly 604. Bristle
receiving holes 620 are filled with clumps of scrubbing bristles
616 which are bonded or otherwise held therein. In one example
embodiment, two spiral patterns of receiving holes 620 are
populated with bristles 616. A first spiral pattern has a first
clump 622 and a second clump 624 and subsequent bristle clumps
follow a spiral path pattern 626 around the holder outside
diameter. A second spiral pattern 628 starts with a first clump 630
substantially diametrically opposed to the clump 622. Each pattern
of bristle clumps is offset along the bristle holder longitudinal
axis to contact different points across the cleaning width.
However, the patterns are arranged to scrub the entire cleaning
width with each full rotation of the bristle holder 618. In
addition, the pattern is arranged to fully contact only a small
number of bristle clumps with cleaning surface simultaneously,
(e.g. 2) in order to reduce the bending force exerted upon and the
torque required to rotate the scrubbing brush assembly 604. Of
course, other scrubbing brush configurations having different
bristle patterns, materials and insertion angles are usable. In
particular, bristles at the right edge of the scrubbing element may
be inserted at an angle and made longer to extend the cleaning
action of the scrubbing brush further toward the right edge of the
robot for cleaning near the edge of a wall.
[0097] The scrubbing brush assembly 604 couples with a scrubbing
brush rotary drive module 606 which is shown schematically in FIG.
13. The scrubbing brush rotary drive module 606 includes a DC brush
rotary drive motor 608, which is driven at a constant angular
velocity by a motor driver 650. The motor driver 650 is set to
drive the motor 608 at a voltage and DC current level that provides
the desired angular velocity of the rotary brush assembly 604,
which in the preferred embodiment is 1500 RPM. The drive motor 608
is drive coupled to a mechanical drive transmission 610 that
increases the drive torque and transfers the rotary drive axis from
the drive motor 608, which is positioned on the top side of the
chassis 200, to the rotation axis of the scrubbing brush assembly
604, which is positioned on a bottom side of the chassis 200. A
drive coupling 642 extends from the mechanical drive transmission
610 and mates with the rotatable scrubbing brush assembly 604 at
its left end. The action of sliding the scrubber module 600 into
the cavity 602 couples the left end of the rotatable brush assembly
604 with the drive coupling 642. Coupling of the rotatable brush
assembly 604 aligns its left end with a desired rotation axis,
supports the left end for rotation, and delivers a rotary drive
force to the left end. The right end of the brush assembly 604
includes a bushing or other rotational support element 643 for
interfacing with bearing surfaces provided on the module housing
elements 634, 636.
[0098] The scrubber module 600 further includes a molded right end
element 644, which encloses the right end of the module to prevent
debris and spray from escaping the module. The right end element
644 is finished on its external surfaces to integrate with the
style and form of adjacent external surfaces of the robot 100. The
lower housing element 634 is configured to provide attaching
features for attaching the smearing brush 612 to its forward edge
and for attaching the squeegee 630 to its aft edge. A pivotal
latching element 646 is shown in FIG. 10 and is used to latch the
scrubber module 600 in its operating position when it is correctly
installed in the cavity 632. The latch 646 attaches to attaching
features provided on the top side of the chassis 200 and is biased
into a closed position by a torsion spring 648. A latching claw 649
passes through the chassis 200 and latches onto a hook element
formed on the upper housing 636. The structural elements of the wet
cleaning module 600 may be molded from a suitable plastic material
such as a Polycarbonate (PC) (ABS) blend. In particular, these
include the lower housing 634, the upper housing 636, the right end
element 644, and the latch 646.
500 Air Moving Subsystems
[0099] FIG. 14 depicts a schematic representation of a wet dry
vacuum module 500 and its interface with the cleaning elements of
the robot 100. The wet dry vacuum module 500 interfaces with the
first collecting apparatus to suction up loose particulates from
the cleaning surface and with the second collecting apparatus to
suction up waste liquid from the cleaning surface. The wet dry
vacuum module 500 also interfaces with an integrated liquid storage
container 800 attached to the chassis 200 and deposits loose
particulates and waste liquid into one or more waste containers
housed therein.
[0100] Referring to FIGS. 14 and 15, the wet dry vacuum module 500
comprises a single fan assembly 502; however, two or more fans can
be used without deviating from the present invention. The fan
assembly 502 includes a rotary fan motor 504, having a fixed
housing 506 and a rotating shaft 508 extending therefrom. The fixed
motor housing 506 attaches to the fan assembly 502 at an external
surface of a rear shroud 510 by threaded fasteners, or the like.
The motor shaft 508 extends through the rear shroud 510 and a fan
impeller 512 is attached to the motor shaft 508 by a press fit, or
by another appropriate attaching means, for causing the impeller
512 to rotate with the motor shaft 508. A front shroud 514 couples
with the rear shroud 510 for housing the fan impeller 512 in a
hollow cavity formed between the front and rear shrouds. The fan
front shroud 514 includes a circular air intake port 516 formed
integral therewith and positioned substantially coaxial with a
rotation axis of the motor shaft 508 and impeller 512. The front
and rear shrouds 510, 514 together form an air exit port 518 at a
distal radial edge of the fan assembly 502.
[0101] The fan impeller 512 generally comprises a plurality of
blade elements arranged about a central rotation axis thereof and
configured to draw air axially inward along its rotation axis and
expel the air radially outward when the impeller 718 is rotated.
Rotation of the impeller 512 creates a negative air pressure zone,
or vacuum, on its input side and a positive air pressure zone at
its output side. The fan motor 710 is configured to rotate the
impeller 715 at a substantially constant rate of rotational
velocity, e.g. 14,000 RPM.
[0102] As shown schematically in FIG. 14, a closed air duct or
conduit 552 is connected between the fan housing exit port 518 and
the air jet port 554 of the first cleaning zone A and delivers high
pressure air to the air jet port 554. At the opposite end of the
first cleaning zone A, a closed air duct or conduit 558 fluidly
connects the air intake port 556 with the integrated liquid storage
container module 800 at a container intake aperture 557. Integral
with the integrated storage container 800 is a conduit 832,
detailed below, fluidly connects the container intake aperture 557
with a plenum 562. The plenum 562 comprises a union for receiving a
plurality of air ducts connected thereto. The plenum 562 is
disposed above a waste storage container portion of the integrated
liquid storage container module 800. The plenum 562 and waste
container portion are configured to deposit loose particulates
suctioned up from the cleaning surface by the air intake port 556
into the waste container. The plenum 652 is in fluid communication
with the fan intake port 516 via a closed air duct or conduit
comprising a conduit 564, not shown, connected between the fan
assembly and a container air exit aperture 566. The container air
exit aperture 566 is fluidly connected with the plenum 562 by an
air conduit 830 that is incorporated within the integrated liquid
storage tank module 800. Rotation of the fan impeller 512 generates
a negative air pressure or vacuum inside the plenum 560. The
negative air pressure generated within the plenum 560 draws air and
loose particulates in from the air intake port 556.
[0103] As further shown schematically in FIG. 14, a pair of closed
air ducts or conduits 666 interface with scrubbing module 600 of
the second cleaning zone B. The air conduits 666, shown in section
view in FIG. 10 comprise external tubes extending downwardly from
the integrated liquid container module 800. The external tubes 666
insert into the scrubber module upper housing gaskets 670.
[0104] As shown in FIG. 14, conduits 834 and 836 fluidly connect
each external tube 666 to the plenum 652. Negative air pressure
generated within the plenum 652 draws air from the vacuum chamber
664 via the conduits 834, 836 and 666 to suction up waste liquid up
from the cleaning surface via the suction ports 668 passing from
the vacuum chamber 664 to the waste liquid collecting volume 674.
The waste liquid is draw into the plenum 562 and deposited into the
waste liquid storage container.
[0105] Of course other wet dry vacuum configurations are usable
without deviating from the present invention. In one example, a
first fan assembly may be configured to collect loose particulates
from the first cleaning zone and deposit the loose particulates in
the first waste storage container and a second fan assembly may be
configured to collect waste liquid from the second cleaning zone
and deposit the waste liquid into a second waste storage
container.
Integrated Liquid Storage Tank
[0106] Elements of the integrated liquid storage container module
800 are shown in FIGS. 1, 12, 14, 16 and 17. Referring to FIG. 16,
the integrated liquid storage container 800 is formed with at least
two liquid storage container portions. One container portion
comprises a waste container portion and the second container
portion comprises a cleaning fluid storage container portion. In
the prefer embodiment of the present invention the two storage
containers are formed as an integral unit that is configured to
attach the chassis 200 and to be removable from the chassis by a
user to empty the waste container portion and to fill the cleaning
fluid container portion. In an alternate embodiment, the integrates
storage containers can be filled and emptied autonomously hen the
robot 100 is docked with a bas station configured for transferring
cleaning fluid and waste material to and from the robot 100. The
cleaning fluid container portion S comprises a sealed supply tank
for holding a supply the cleaning fluid. The waste container
portion W comprises a sealed waste tank for storing loose
particulates collected by the first collecting apparatus and for
storing waste liquid collected by the second collecting
apparatus.
[0107] The waste container W comprises a first molded plastic
element formed with a base surface 804 and an integrally formed
perimeter wall 806 disposed generally orthogonal from the base
surface 804. The base surface 804 is formed with various contours
to conform to the space available on the chassis 200 and to provide
a detent area 164 that is used to orient the integrated liquid
storage container module 800 on the chassis 200. The detent 164
includes a pair of channels 808 that interface with corresponding
alignment rails 208 formed on a hinge element 202, attached to the
chassis 200 and described below. The perimeter wall 806 includes
finished external surfaces 810 that are colored and formed in
accordance with the style and form of other external robot
surfaces. The waste tank D may also include a tank level sensor
housed therein and configured to communicate a tank level signal to
the master controller 300 when the waste tank D is full. The level
sensor may comprise a pair of conductive electrodes disposed inside
the tank and separated from each other. A measurement circuit
applies an electrical potential difference between the electrodes
from outside the tank. When the tank is empty no current flow
between the electrodes. However, when both electrodes are submerged
in waste liquid, current flows through the waste liquid from one
electrode to the other. Accordingly, the electrodes may be located
at positions with the tank for sensing the level of fluid within
the tank.
[0108] The cleaning fluid storage container S is formed in part by
a second molded plastic element 812. The second molded element 812
is generally circular in cross-section and formed with a
substantially uniform thickness between opposing top and bottom
surfaces. The element 812 mates with the waste container perimeter
wall 810 and is bonded or otherwise attached thereto to fluidly
seal the waste container W. The plenum 562 is incorporated into the
second molded element 812 and positioned vertically above the waste
container W when the cleaning robot is operating. The plenum 562
may also comprise a separate molded element.
[0109] The second molded element 812 is contoured to provide a
second container portion for holding a supply of cleaning fluid.
The second container portion is formed in part by a downwardly
sloping forward section having an integrally formed first perimeter
wall 816 disposed generally vertically upward. The first perimeter
wall 816 forms a first portion of an enclosing perimeter wall of
the liquid storage container S. The molded element 812 is further
contoured to conform to the space available on the chassis 200. The
molded element 812 also includes the container air input aperture
840, for interfacing with first cleaning zone air conduit 558. The
molded element 812 also includes the container air exit aperture
838, for interfacing with the fan assembly 502 via the conduit
564.
[0110] A molded cover assembly 818 attaches to molded element 812.
The cover assembly 818 includes a second portion of the supply tank
perimeter wall formed thereon and provides a top wall 824 of the
supply tank enclosure. The cover assembly 818 attaches to the first
perimeter wall portion 816 and to other surfaces of the molded
element 814 and is bonded or otherwise attached thereto to fluidly
seal the supply container S. The supply container S may include a
tank empty sensor housed therein and configured to communicate a
tank empty signal to the master controller 300 when the upper tank
is empty.
[0111] The cover assembly 818 comprises a molded plastic cover
element having finished external surfaces 820, 822 and 824. The
finished external surfaces are finished in accordance with the
style and form of other external robot surfaces and may therefore
be colored and or styled appropriately. The cover assembly 818
includes user access ports 166 to the waste container W, and 168 to
the supply container S. The cover assembly 818 also includes the
handle 162 and a handle pivot element 163 attached thereto and
operable to unlatch the integrated liquid storage tank 800 from the
chassis 200 or to pick up the entire robot 100.
[0112] According to the invention, the plenum 562 and each of the
air conduits 830, 832, 834 and 836 are inside the cleaning fluid
supply container S and the inter-connections of each of these
elements are liquid and gas sealed to prevent cleaning fluid and
waste materials from being mixed together. The plenum 562 is formed
vertically above the waste container W so that waste liquid waste
and loose particulates suctioned into the plenum 562 will drop into
the waste container W under the force of gravity. The plenum side
surfaces 828 include four apertures formed therethrough for
interconnecting the plenum 562 with the four closed air conduits
interfaced therewith. Each of the four closed air conduits 830,
832, 834 and 836 may comprise a molded plastic tube element formed
with ends configured to interface with an appropriate mating
aperture.
[0113] As shown in FIG. 16, the container air exit aperture 838 is
generally rectangular and the conduit 830 connecting the container
air exit aperture 838 and the plenum 562 is shaped with a generally
rectangular ends. This configuration provides a large area exit
aperture 838 for receiving an air filter associated therewith. The
air filter is attached to the fan intake conduit 564 to filter air
drawn in by the fan assembly 502. When the integrated storage tank
800 is removed from the robot, the air filter remains attached to
the air conduit 564 and may be cleaned in place or removed for
cleaning or replacement as required. The area of the air filter and
the container exit aperture 838 are formed large enough to allow
the wet dry vacuum system to operate even when up to 50% of the air
flow through the filter is blocked by debris trapped therein.
[0114] Each of the container apertures 840 and 838 are configured
with a gasket, not shown, positioned external to the container
aperture. The gaskets provide substantially airtight seal between
the container assembly 800 and the conduits 564 and 558. In a
preferred embodiment, the gaskets remain affixed to the chassis 200
when the integrated liquid supply container 800 is removed from the
chassis 200. The seal is formed when the container assembly 800 is
latched in place on the robot chassis. In addition, some of the
container apertures may include a flap seal or the like for
preventing liquid from exiting the container while it is carried by
a user. The flap seal remains attached to the container.
[0115] Thus according to the present invention, the fan assembly
502 generates a negative pressure of vacuum which evacuates air
conduit 564, draws air through the air filter disposed at the end
of air conduit 564, evacuates the fan intake conduit 830 and the
plenum 562. The vacuum generated in the plenum 562 draws air from
each of the conduits connected thereto to suction up loose
particulates proximate to the air intake port 556 and to draw waste
liquid up form the cleaning surface via the air conduits 834, 836
and 666, and via the vacuum chamber 664 and the suction ports 668.
The loose particulates and waste liquid drawn into the plenum 562
and fall into the waste container W.
[0116] Referring to FIGS. 1, 3 16 and 17 the integrated liquid
storage container 800 attaches to a top side of the robot chassis
200 by a hinge element 202. The hinge element 202 is pivotally
attached to the robot chassis 200 at an aft edge thereof. The
liquid storage container 800 is removable from the robot chassis
200 by a user and the user may fill the cleaning fluid supply
container S with clean water and a measured volume of cleaning
fluid such as soap or detergent. The user may also empty waste from
the waste container W and flush out the waste container if
needed.
[0117] To facilitate handling, the integrated liquid storage tank
800 includes a user graspable handle 162 formed integral with the
cover assembly 818 at a forward edge of the robot 100. The handle
162 includes a pivot element 163 attached thereto and attached by a
hinge arrangement to the cover assembly 818. In one mode of
operation, a user may grasp the handle 162 to pick up the entire
robot 100 thereby. In the preferred embodiment, the robot 100
weights approximately 3-5 kg, (6.6-11 pounds), when filled with
liquids, and can be easily carried by the user in one hand.
[0118] In a second mode of operation, the handle 162 is to remove
the integrated tank 800 from the chassis 200. In this mode, the
user presses down on an aft edge of the handle 162 to initially
pivot the handle downward. The action of the downward pivot
releases a latching mechanism, not shown, that attaches a forward
edge of the liquid storage container 800 to the robot chassis 200.
With the latching mechanism unlatched the user grasps the handle
162 and lifts vertically upwardly. The lifting force pivots the
entire container assembly 800 about a pivot axis 204, provided by a
hinge element which pivotally attached to the aft edge of the
chassis 200. The hinge element 202 supports the aft end of the
integrated liquid storage container 800 on the chassis 200 and
further lifting of the handle rotates the hinge element 202 to an
open position that facilities removal of the container assembly 800
from the chassis 200. In the open position, the forward edge of the
liquid storage container 800 is elevated such that further lifting
of the handle 162 lifts the liquid storage tank 800 out of
engagement with the hinge element 202 and separates it from the
robot 100.
[0119] As shown in FIG. 17, the integrated liquid storage container
800 is formed with recessed aft exterior surfaces forming a detent
area 164 and the detent area 164 is form matched to a receiving
area of the hinge element 202. As shown in FIG. 3, the hinge
element receiving area comprises a clevis-like cradle having upper
and lower opposed walls 204 and 206 form matched to engage with and
orient the storage container detent area 164. The alignment of the
detent area 164 and the hinge walls 204 and 206 aligns the
integrated storage container 800 with the robot chassis 200 and
with the latching mechanism used to attach the container forward
edge to the chassis 200. In particular, the lower wall 206 includes
alignment rails 208 form-matched to mate with grooves 808 formed on
the bottom side of the detent area 164. In FIG. 3, the hinge
element 202 is shown pivoted to a fully open position for loading
and unloading the storage container 800. The loading and unloading
position is rotated approximately 75.degree. from a closed or
operating position; however other loading and unloading
orientations are usable. In the loading and unloading position, the
storage container detent area 164 is easily engaged or disengaged
from the clevis-like cradle of the hinge element 202. As shown in
FIG. 1, the integrated liquid storage tank 800 and the hinge
element 202 are configured to provide finished external surfaces
that integrate smoothly and stylishly with other external surfaces
of the robot 100.
[0120] Two access ports are provided on an upper surface of the
liquid storage container 800 in the detent area 164 and these are
shown in FIGS. 16 and 17. The access ports are located in the
detent area 164 so as to be hidden by the hinge element upper wall
204 when the liquid storage tank assembly 800 is in installed in
the robot chassis 200. A left access port 166 provides user access
to the waste container W through the plenum 562. A right access
port 168 provides user access to the cleaning fluid storage
container S. The left and right access ports 166, 168 are sealed by
user removable tank caps that may be color or form coded to be
readily distinguishable.
Transport Drive System 900
[0121] In the preferred embodiment, the robot 100 is supported for
transport over the cleaning surface by a three-point transport
system 900. The transport system 900 comprises a pair of
independent rear transport drive wheel modules 902 on the left
side, and 904 on the right side, attached to the chassis 200 aft of
the cleaning modules. In a preferred embodiment, the rear
independent drive wheels 902 and 904 are supported to rotate about
a common drive axis 906 that is substantially parallel with the
transverse axis 108. However, each drive wheel may be canted with
respect to the transverse axis 108 such that each drive wheel has
its own drive axis orientation. The drive wheel modules 902 and 904
are independently driven and controlled by the master controller
300 to advance the robot in any desired direction. The left drive
module 902 is shown protruding from the underside of the chassis
200 in FIG. 3 and the right drive module 904 is shown mounted to a
top surface of the chassis 200 in FIG. 4. In the preferred
embodiment, each of the left and right drive modules 902 and 904 is
pivotally attached to the chassis 200 and forced into engagement
with the cleaning surface by leaf springs 908, shown in FIG. 3. The
leaf springs 908 are mounted to bias the each rear drive module to
pivot downwardly toward the cleaning surface when the drive wheel
goes over a cliff or is otherwise lifted from the cleaning surface.
A wheel sensor associated with each drive wheel senses when a wheel
pivots down and sends a signale to the master controller 300.
[0122] The drive wheels of the present invention are particularly
configured for operating on wet soapy surfaces. In particular, as
shown in FIG. 20, each drive wheel 1100 comprises a cup shaped
wheel element 1102, which attaches to the a drive wheel module, 902
and 904. The drive wheel module includes a drive motor and drive
train transmission for driving the drive wheel for transport. The
drive wheel module may also include sensor for detecting wheel slip
with respect to the cleaning surface.
[0123] The cup shaped wheel elements 1102 is formed from a stiff
material such as a hard molded plastic to maintain the wheel shape
and to provide stiffness. The cup shaped wheel element 1102
provides an outer diameter 1104 sized to receive an annular tire
element 1106 thereon. The annular tire element 1106 is configured
to provide a non-slip high friction drive surface for contacting
the wet cleaning surface and for maintaining traction on the wet
soapy surface.
[0124] The annular tire element 1106 comprises an internal diameter
1108 of approximately 37 mm and sized to fit appropriately over the
outer diameter 1104. The tire may be bonded taped or otherwise
contacted to the outer diameter 1104 to prevent slipping between
the tire inside diameter 1108 and the outside diameter 1104. The
tire radial thickness 1110 is approximately 3 mm. The tire material
comprises a chloroprene homopolymer stabilized with thiuram
disulfide black with a density of 15 pounds per cubic foot foamed
to a cell size of 0.1 mm plus or minus 0.002 mm. The tire has a
post-foamed hardness 69 shore 00. The tire material is sold by
Monmouth Rubber and plastics Corporation under the trade name
DURAFOAM DK5151HD.
[0125] To increase traction, the outside diameter of the tire is
sipped. The term sipped refers to slicing the tire material to
provide a pattern of thin grooves 1110 in the tire outside
diameter. In the preferred embodiment, each groove has a depth of
approximately 1.5 mm and a width or approximately 20 to 300
microns. The groove pattern provides grooves that are substantially
evenly spaced apart with approximately 2 to 200 mm spaces between
adjacent grooves. The groove cut axis makes an angle G with the
tire longitudinal axis and the angle G ranges from 10-50
degrees.
[0126] The nose wheel module 960, shown in exploded view in FIG. 18
and in section view in FIG. 19, includes a nose wheel 962 housed in
a caster housing 964 and attached to a vertical support assembly
966. The nose wheel module 960 attaches to the chassis 200 forward
of the cleaning modules and provide a third support element for
supporting the chassis 200 with respect to the cleaning
surface.
[0127] The vertical support assembly 966 is pivotally attached to
the caster housing 964 at a lower end thereof and allows the caster
housing to pivot away from the chassis 200 when the chassis is
lifted from the cleaning surface or when the nose wheel goes over a
cliff. A top end of the vertical support assembly 966 passes
through the chassis 200 and is rotatably supported with respect
thereto to allow the entire nose wheel module 960 to rotate freely
about a substantially vertical axis as the robot 100 is being
transported over the cleaning surface by the rear transport drive
wheels 902 and 904. Accordingly, the nose wheel module is
self-aligning with respect to the direction of robot transport.
[0128] The chassis 200 is equipped with a nose wheel mounting well
968 for receiving the nose wheel module 960 therein. The well 968
is formed on the bottom side of the chassis 200 at a forward
circumferential edge thereof. The top end of the vertical support
assembly 966 passes through a hole through the chassis 200 and is
captured in the hole to attach the nose wheel to the chassis. The
top end of the vertical support assembly 966 also interfaces with
sensor elements attached to the chassis 200 on its top side.
[0129] The nose wheel assembly 962 is configured with a molded
plastic wheel 972 having axle protrusions 974 extending therefrom
and is supported for rotation with respect to the caster housing
964 by opposed co-aligned axle holes 970 forming a drive wheel
rotation axis. The plastic wheel 972 includes with three
circumferential grooves in its outer diameter. A center groove 976
is providing to receive a cam follower 998 therein. The plastic
wheel further includes a pair of symmetrically opposed
circumferential tire grooves 978 for receiving an elastomeric
o-ring 980 therein. The elastomeric o-rings 980 contacts the
cleaning surface during operation and the o-ring material
properties are selected to provide a desired friction coefficient
between the nose wheel and the cleaning surface. The nose wheel
assembly 962 is a passive element that is in rolling contact with
the cleaning surface via the o-rings 980 and rotates about its
rotation axis formed by the axle protrusion 974 when the robot 100
is transported over the cleaning surface.
[0130] The caster housing 964 is formed with a pair of opposed
clevis surfaces with co-aligned opposed pivot holes 982 formed
therethrough for receiving the vertical support assembly 966
therein. A vertical attaching member 984 includes a pivot element
986 at its bottom end for installing between the clevis surfaces.
The pivot element 986 includes a pivot axis bore 988 formed therein
for alignment with the co-aligned pivot hole 982. A pivot rod 989
extends through the co-aligned pivot holes 982 and is press fit
within the pivot axis bore 988 and captured therein. A torsion
spring 990 installs over the pivot rod 988 and provides a spring
force that biases the caster housing 964 and nose wheel assembly
962 to a downwardly extended position forcing the nose wheel 962 to
rotate to an orientation that places the nose wheel 962 more
distally below the bottom surface of the chassis 200. The
downwardly extended position is a non-operating position. The
spring constant of the torsion spring 990 is small enough that the
weight of the robot 100 overcomes its biasing force when the robot
100 robot is placed onto the cleaning surface for cleaning.
Alternately, when the nose wheel assembly goes over a cliff, or is
lifted off the cleaning surface, the torsion spring biasing force
pivots the nose wheel to the downwardly extended non-operating
position. This condition is sensed by a wheel down sensor,
described below, and a signal is sent to the master controller 300
to stop transport or to initiate some other action.
[0131] The vertical attaching member 984 includes a hollow vertical
shaft portion 992 extending upward from the pivot element 986. The
hollow shaft portion 992 passes through the hole in the chassis 200
and is captured therein by an e-ring retainer 994 and thrust washer
996. This attaches the nose wheel assembly 960 to the chassis and
allows it to rotate freely about a vertical axis when the robot is
being transported.
[0132] The nose wheel module 960 is equipped with sensing elements
that generate sensor signals used by the master control module 300
to count wheel revolutions, to determine wheel rotational velocity,
and to sense a wheel down condition, i.e. when the caster 964 is
pivoted downward by the force of the torsion spring 990. The
sensors generate a wheel rotation signal using a cam following
plunger 998 that include a sensor element that moves in response to
wheel rotation. The cam follower 998 comprises an "L" shaped rod
with the a vertical portion being movably supported inside the
hollow shaft 992 thus passing through the hole in the chassis 200
to extend above the top surface thereof. The lower end of the rod
992 forms a cam follower that fits within the wheel center
circumferential groove 976 and is movable with respect thereto. The
cam follower 998 is supported in contact with an offset hub 1000
shown in FIG. 18. The offset hub 1000 comprises an eccentric
feature formed non-symmetrically about the nose wheel rotation axis
inside the circumferential groove 976. With each rotation of the
wheel 962, the offset hub 1000 forces and oscillation of the cam
follower 998 which moves reciprocally along a substantially
vertical axis.
[0133] A once per revolution wheel sensor includes a permanent
magnet 1002 attached to the top end of the "L" shaped rod by an
attaching element 1004. The magnet 1002 oscillates through a
periodic vertical motion with each full revolution of the nose
wheel. The magnet 1002 generates a magnetic field which is used to
interact with a reed switch, not shown, mounted to the chassis 200
in a fixed location with respect to moving magnet 1002. The reed
switch is activated by the magnetic field each time the magnet 1002
is in the full up position in its travel. This generates a once per
revolution signal which is sensed by the master controller 300. A
second reed switch may also be positioned proximate to the magnet
1002 and calibrated to generate a wheel down signal. The second
reed switch is positioned in a location that will be influenced by
the magnetic field when the magnet 1002 drops to the non-operating
wheel down position. It will also be recognized by those skilled in
the art that, while the invention has been described above in terms
of preferred embodiments, it is not limited thereto. Various
features and aspects of the above described invention may be used
individually or jointly. Further, although the invention has been
described in the context of its implementation in a particular
environment, and for particular applications, e.g. residential
floor cleaning, those skilled in the art will recognize that its
usefulness is not limited thereto and that the present invention
can be beneficially utilized in any number of environments and
implementations including but not limited to cleaning any
horizontal surface. Accordingly, the claims set forth below should
be construed in view of the full breadth and spirit of the
invention as disclosed herein.
* * * * *