U.S. patent application number 09/772893 was filed with the patent office on 2001-06-21 for service robot for the automatic suction of dust from floor surfaces.
Invention is credited to Sommer, Volker.
Application Number | 20010004719 09/772893 |
Document ID | / |
Family ID | 26048049 |
Filed Date | 2001-06-21 |
United States Patent
Application |
20010004719 |
Kind Code |
A1 |
Sommer, Volker |
June 21, 2001 |
Service robot for the automatic suction of dust from floor
surfaces
Abstract
The present invention is used for the complete and fully
automatic examination of floor surfaces of all kind as well as for
a particularly efficient suction of dust therefrom since the lower
areas, the edges and the recessed can be detected. In each case,
the robot is controlled so as to explore the adjacent area and to
detect the potential obstacles using special sensors before storing
them in a data field. The displacement towards a new location is
then carried out using the stored data until the whole accessible
surface has been covered. One of the main constituent members of
the robot consists of an extensible arm that rests on the robot and
on which contact and range sensors are arranged. When the robot is
used as an automatic vacuum cleaner, an air flow is forced into the
robot arm and the -cleaning effect can further be enhanced by
providing one or more Circular rotary brushes at the front end of
the arm. This invention can essentially be used for domestic or
industrial Cleaning purposed with a view to replace traditional
vacuum cleaners.
Inventors: |
Sommer, Volker; (Berlin,
DE) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
26048049 |
Appl. No.: |
09/772893 |
Filed: |
January 31, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09772893 |
Jan 31, 2001 |
|
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PCT/DE99/02276 |
Jul 22, 1999 |
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Current U.S.
Class: |
701/23 ; 15/319;
340/435 |
Current CPC
Class: |
A47L 2201/04 20130101;
G05D 1/0219 20130101; G05D 2201/0215 20130101; A47L 11/4044
20130101; A47L 11/4011 20130101; A47L 11/12 20130101; A47L 5/30
20130101; G05D 1/0255 20130101; G05D 1/0227 20130101; G05D 1/0274
20130101; A47L 11/4038 20130101 |
Class at
Publication: |
701/23 ; 15/319;
340/435 |
International
Class: |
G05D 001/00; A47L
009/28 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 31, 1998 |
DE |
198 36 093.2 |
Apr 7, 1999 |
DE |
199 16 427.4 |
Claims
1. Method of automatic controlling a self-moving device, especially
a vacuum cleaner, with range-, respectively contact-sensors,
wherein a closer area around the device is individually determined
and scanned, e. g. by a movable arm, and wherein possible new
positions at the borders of the closer area are stored and the
device is then moved to a respective new position until no position
can be selected anymore; at this, the determination of the closer
area and the selection of the position is realised mainly on the
basis of the information of the surroundings, which is stored in a
data field and updated in each step, at this, to determine the
respective next position, an optimising out of all positions, which
have been stored and can be approached by the device, is performed
by calculating and comparing for each of these positions certain
evaluation parameters, like distances or areas in the reach of a
possible new position, which have not yet been scanned, and by
selecting the position with the best evaluation result.
2. Method of automatic controlling a self-moving device, especially
a vacuum cleaner, with range-, respectively contact-sensors,
wherein a closer area in form of a sector of a circle around the
device is scanned by a movable arm, and wherein the device then is
moved to a new position and the process is repeated in a loop; at
this the scanning of the closer area is realised, starting with the
retracted state of the arm, by repeated turns to the left and the
right with an increased length of the arm at each turn, until the
given maximum arm length is reached and the arm is then, following
a last turn, retracted again.
3. Method as claimed in claim 1, wherein after the detection of an
obstacle by a sensor, the exact position of the obstacle is
determined under consideration of the scannig direction.
4. Method as claimed in claim 1, wherein after the scanning of the
closer area, new positions are stored only where no obstacles have
been detected and also where no areas border, which have already
been scanned before from a previous position of the device.
5. Method as claimed in claim 1, wherein when scanning again an
area already marked in the data field, every state of this area is
updated according to the new sensor data.
6. Method as claimed in claim 1, wherein when selecting a new
position for the device, only positions, which in the data field
are not marked as already scanned, are taken into
consideration.
7. Method as claimed in claim 1, wherein when storing new
positions, different priorities are assigned to these positions,
and wherein when selecting a new position for the device, only such
positions are considered, whose priorities are not inferior to that
of a position already preliminarily selected in the current
step.
8. Method as claimed in claim 1, wherein when selecting a new
position, only such positions are taken into consideration, which
are located within a certain partial area, and wherein this partial
area will be modified during the process, if within the current
partial area no new position can be selected.
9. Method as claimed in claim 1, wherein when selecting a new
position, the distance and/or the direction between a possible new
position and the respective current position of the device is taken
into consideration.
10. Method as claimed in claim 1, wherein when selecting a new
position, the covered distance since the storage of a position is
taken into consideration.
11. Method as claimed in claim 1, wherein when selecting a new
position for the device, it is guaranteed by evaluation of the data
field, that the new position can be reached by the device on a
direct route, allowing only areas to be traversed, which have
already been scanned and which are not marked as an obstacle.
12. Method as claimed in claim 1, wherein after the selection of a
new position, by evaluating of the data field, the shortest route
to the new position within the already scanned area under
circumvention of obstacles is determined, and wherein the device is
moved along this route.
13. Method as claimed in claim 1, wherein the device can be set
back to any previous position and wherein in setting back the
device over several previous positions, certain positions in
between can be skipped, if the evaluation of the data field
reveals, that the device does not need to traverse areas which are
marked as an obstacle while moving.
14. Method as claimed in claim 1, wherein , if an unexpected
obstacle blocks the movement of the device, the device will detect
the contours of the obstacle by scanning it with its sensors.
15. Method as claimed in claim 1, wherein after approaching a new
position, the new closer area is determined by evaluating the data
field, so that only a small overlap with already scanned
neighbouring areas occurs.
16. Method as claimed in claim 1, wherein the movable arm is used
to clean the floor surface at the same time as the planning is
performed.
17. Method as claimed in claim 2, wherein the movable arm is used
to clean the floor surface at the same time as the scanning is
performed.
18. Method as claimed in claim 1, wherein the scanning is realised
by means of the movable arm so that not yet scanned areas are
covered first by the front end of the arm.
19. Method as claimed in claim 1, wherein the scanning is realised
by means of the movable arm whose front end is guided along the
detected obstacle at the smallest possible range.
20. Method as claimed in claim 2, wherein the scanning is realised
by means of the movable arm whose front end is guided along the
detected obstacle at the smallest possible range.
21. Method as claimed in claim 1, wherein the scanning by means of
the movable arm in the closer area around the device is selected in
form of the sector of a circle.
22. Method as claimed in claim 1, wherein the scanning is realised
by repeated turns of the device to the left and the right with
increased length of the movable arm at each turn.
23. Method as claimed in claim 1, wherein the scanning is realised
by repeated turns of the device to the left and the right with
increased length of the movable arm at each turn with the repeated
scanning of already detected obstacles being prevented by
shortening the arm in the range of those angles where an obstacle
has already been detected.
24. Method as claimed in claim 2, wherein the scanning is realised
by repeated turns of the device to the left and the right with
increased length of the movable arm at each turn with the repeated
scanning of already detected obstacles being prevented by
shortening the arm in the range of those angles where an obstacle
has already been detected.
25. Method as claimed in claim 16, wherein by evaluating the
information in the data field, the cleaning of the floor surface is
performed only in those areas, which are marked as not yet cleaned
in the data field.
26. Method as claimed in claim 1, wherein the suction engine is
only turned on when vacuuming the closer areas and not during the
movement of the device towards a new position.
27. Method as claimed in claim 2, wherein the suction engine is
only turned on when vacuuming the closer areas and not during the
movement of the device towards a new position.
28. Device, especially vacuum cleaner, with propelled wheels and
steering wheels respectively propelling wheels which can be steered
(8) and sensors (13 to 16) and an extensible arm (4) with a head
(11) positioned at its front end, comprising, apart from two
propelled wheels (8), the use of the head (11) as a third support,
which rests on supporting elements like rollers, balls, wheels or
bristles.
29. Device, especially vacuum cleaner, with propelled wheels and
steering wheels respectively propelling wheels which can be steered
(8)and sensors (13 to 16) and an extensible arm (4) with a head
(11) positioned at its front end, comprising at least one propelled
circular brush (12) positioned at the head.
30. Device, especially vacuum cleaner, with propelled wheels and
steering wheels respectively propelling wheels which can be steered
(8) and sensors and an extensible arm (4) with a head (11)
positioned at its front end, comprising a contact sensor (14)
positioned at the head, with which obstacles for the movement of
the arm (4) are detected, and a step sensor (15) as well as a
height sensor (13) positioned at the head which are used to detect
such obstacles which indeed do not block the arm (4), but the
movement of the device.
31. Device, as claimed in claim 28, comprising the arm (4)
constructed as a telescope arm.
32. Device, as claimed in claim 29, comprising the arm (4)
constructed as a telescope arm.
33. Device, as claimed in claim 30, comprising the arm (4)
constructed as a telescope arm.
34. Device, as claimed in claim 28, comprising the possible
variation of the resting-pressure of the head (11) by shifting of
weight.
35. Device, as claimed in claim 29, comprising the arm (4)
constructed as a telescope arm, which at its rear end is mounted
rotating around a horizontal axis respectively vertically
flexible.
36. Device, as claimed in claim 30, comprising the arm (4)
constructed as a telescope arm, which at its rear end is mounted
rotating around a horizontal axis respectively vertically
flexible.
37. Device, as claimed in claim 29, comprising one or several
brushes (12), driven, using a movable shaft (6), by a motor (9),
which is positioned on the base of the device(1).
38. Device, as claimed in claim 29, comprising at least one brush
(12) with bristles (21) which are adjusted diagonally towards the
inner part of the brush and which is surrounded by a circle of soft
bristles (22) which are adjusted diagonally towards the outer part
of the brush.
39. Device, as claimed in claim 30, comprising the contact sensor
(14) constructed in form of two electrical conductors positioned
within a short distance to each other around the head (11) of the
arm (4), from which the outer conductor (20) is pressed elastically
against the inner conductor (19) when touching an obstacle, thus
closing an electrical circuit.
40. Device, as claimed in claim 30, comprising a height sensor
(13), applying ultrasonic or electromagnetic waves, to measure the
clear height above the head (11).
41. Device, as claimed in claim 30, comprising a step sensor (15),
in form of a mechanical push button or contact-free, to detect
steps in the floor surface.
Description
BACKGROUND OF THE INVENTION
[0001] Nowaday commercial household vacuum cleaners resemble in
function and handling basically the models from the beginning of
the twentieth century, even if in the fields of improvement oft the
suction power, noise emission and air-filters continuous
improvements could be reached during the years. The various models
available on the market differ apart from their design mainly in
the power of their engines, which in some cases can be controlled
electronically, the noise damping and the quality of their
filters.
[0002] The classical floor vacuum cleaner consists of an engine
block on wheels, with which by means of a tube various nozzles can
be connected. For the suction of floor surfaces, usually a rigid
nozzle mounted on a telescope handle, which renders possible to
clean an area of about 20 cm width, is used. As an alternative, the
engine block can be integrated in the telescope handle. For smooth
floor surfaces, most models possess a short brush, which can be
pushed out of the nozzle by means of a switch operated by hand or
foot. Additionally, with some models a nozzle with an horizontally
rotating brush can be used to enhance the cleaning effect. The
drive of this brush is realised electrically or indirect by the air
stream.
DESCRIPTION OF THE RELATED ART
[0003] To enhance the cleaning effect, especially for the use with
cleaning machines, an arrangement of several circular brushes,
which by a planetary gear are put into multiple rotation, is
described in the German patent application 1057154. Known from
cleaning machines as well, are two stationary circular brushes at
the two front ends which the automatic vacuum cleaner in DE 43 07
125 A1 possesses to move dirt from the direct lateral area of the
vacuum cleaner to a stationary suction nozzle.
[0004] In the German patent application DE-OS 21 01 659, a vacuum
cleaner with a telescope suction arm with a circular profile is
described, with a suction nozzle mounted at the end of the arm. The
vacuum cleaner is not mobile, but can only turn within a certain
angle by means of a rectangular positioned steering wheel. There
are no sensors existent, only the lateral parts of the suction
nozzle are seated rotatory by a spring to be able to avoid
obstacles.
[0005] In the British patent application GB 20 38 615 A, a vacuum
cleaner with remote control and a circular base on three wheels,
two of which are driven wheels, is described, with a stationary
suction nozzle beneath the base. A method of steering the device or
sensors are not contained in the patent application.
[0006] The patent application U.S. Ser. No. 5,095,577 describes a
self moving vacuum cleaner, whose suction nozzle is mounted at the
end of a suction tube which is rolled up on a cylinder and thus can
be extended. The device is enabled by mechanical sensors and
steering elements to follow the contour of a wall while extending
the suction nozzle or rolling it up.
[0007] The same mechanism, but able to extend one or two suction
nozzles rectangular to the moving direction of the device, is
described in the patent application U.S. Ser. No. 5,199,996, though
the vacuum cleaner is only moved in parallel courses respectively
in courses rectangular to the prior courses.
[0008] A further method of controlling an automatic vacuum cleaner
is contained in the patent application DE 43 40 771 A1., in which
the vacuum cleaner is guided along the inner contour of the surface
to be cleaned, thus detecting the contours of the surface to be
cleaned. Then, a micro processor compares the form of the surface
to be cleaned with the previously stored contours to select the
most appropriate cleaning programme. For orientation, apart from
optical and ultrasonic sensors on the surface of the vacuum
cleaner, a magnetic field sensor is used to determine the
direction.
[0009] In EP 01 42 594 131 and DE 43 07 125 A1, a similar method of
controlling is described, but with the additional capability of the
vacuum cleaner to plan and perform independently parallel cleaning
courses after one cycle to determine the contours of the surface to
be cleaned, without the previous storing of a cleaning programme
for a certain room.
[0010] The patent application DE 196 14 916 A1 describes an
automatically working moving robot, whose orientation is based
mainly on the stereoscopic evaluation of the data of two video
cameras. A concrete controlling method though is not described.
[0011] In the patent application EP-A-38 26 93, a method of
controlling on the basis of a recursive algorithm is described for
a suction robot, wherein the respective closer area around the
suction robot is cleaned and the suction robot then by moving ahead
and back, followed by a turn with a certain angle of turning, is
moved to a new place until a given area is covered. To determine
the respective new position, a systematic algorithm is
utilised.
[0012] In the patent application U.S. Ser. No. 5,696,675, a moving
robot with a lateral displaceable arm is described, which possesses
a special construction with supporting wheels to support the
Suction arm and whose sensors are able to detect an obstacle for
the arm and for the vacuum cleaner.
[0013] In the patent application U.S. Ser. No. 5,677,836, a device
is described, comprising the transmission of the co-ordinates from
one map to another map.
[0014] In addition to the deterministic controlling methods
mentioned above, on the fair "DOMOTECHNICA 99", a self working
vacuum cleaner was presented, which according to the patent
application EP 0 769 923 31 mainly is controlled stochastically.
Here, the vacuum cleaner moves in a certain direction until an
obstacle, which is detected by sensors, blocks its way. The vacuum
cleaner turns away from the obstacle and continues its way in any
other direction, until a new obstacle forces it to change its
course, and so on.
[0015] Despite of the improvements in certain fields during the
years, vacuum cleaning remains a time consuming and exhausting
housework with nowaday manual means, because frequent bending,
sometimes the moving of objects as well as the strong rubbing of
the suction nozzle are required. Apart from that, because of the
inflexible suction nozzles, damage of delicate furniture may occur
and when changing from smooth surfaces to carpet-covered surfaces,
each time the suction nozzle has to be switched manually to achieve
the best cleaning effect. If narrow places have to be vacuumed, a
troublesome change of the suction nozzle is required.
[0016] The known methods of controlling autonomously working vacuum
cleaners show the following disadvantages:
[0017] Methods of controlling, which require a manual route
planning, are to complicated and very inflexible, because
especially in a household, the floor surface which is to be cleaned
changes continuously because of the moving of objects.
[0018] Methods of controlling, which before starting the actual
vacuum cleaning process detect the border lines of the floor
surface which is to be cleaned and determine their cleaning courses
with this information, are overstrained, if many obstacles, e. g.
furniture, force them to frequent evading movements. Apart from
that, because of the detection of the border lines, it takes a
comparatively long time until the actual suction process starts and
the method only works in closed room areas. Moreover, it is not
possible to define a certain starting point for the vacuum cleaner,
from where the cleaning process is to be started.
[0019] Exclusively stochastic methods of controlling work
unsatisfactorily as well, because certain areas are covered very
often whereas other areas are covered rarely or not at all, so that
an non-uniform cleaning effect is achieved. The cleaning process
also lasts very long and there is no criterion of ending the
process.
[0020] In the recursive method of controlling, described in the
patent application EP-A-38 26 93, the vacuum cleaner has to cover
very far distances because of the continuous moving ahead and
moving back, which leads to long vacuuming times and to a
non-uniform covering of the area. A starting point can be indeed
determined, but the vacuum cleaner moves away from this point in a
certain direction without completely cleaning the direct
environment before.
[0021] The self moving vacuum cleaners controlled by the methods
described above are not suitable to replace the manual vacuum
cleaners because of the following reasons: Powerful vacuum cleaners
possess a bulky form and cannot be used in narrow spaces, also
because the damage of delicate furniture cannot be excluded.
Moreover, except from complicated driving methods, several and
complicated sensors are used which render the devices susceptible
and very expensive. To improve the accessibility, recently very low
devices with a circular base have been developed. But this limits
the possible size of the batteries and so the reach and the power
of the vacuum cleaner, and despite of that, many areas in corners
an niches and along the edges of furniture cannot be cleaned,
because they are not accessible for the vacuum cleaner. Vacuum
cleaners relying on a wire based power supply, in principal because
of the necessary connecting cable are not flexible enough to be
able to clean efficiently housing spaces with numerous
obstacles.
SUMMARY OF THE INVENTION
[0022] Thus, the invention is based on the task to provide a
flexible cleaning system, which on the on hand is able to adapt to
any kind of floor surface with any kind of obstacle, and on the
other hand avoids unnecessary multiple cleanings of certain areas,
while other areas are not sufficiently covered or are not covered
at all. Apart from that, the cleaning process should be enabled to
start at any point determined by the user without having to detect
the contours of the room before.
[0023] To provide a serious alternative to commercial vacuum
cleaners, the device controlled by the method should cover every
floor area as well as edges of furniture and narrow niches, while a
high cleaning effect is necessary and damages have to be excluded.
The device has to be big enough to contain a sufficient capacity of
batteries. By the means of adequate insulation, most of the
produced noise can be damped. Moreover, the vacuum cleaner should
be constructed as simple as possible, be robust and dispense with
complicated sensors to render possible a low cost production .
[0024] The solution of the task results from the characteristics of
the patent claims 1, 2, 24, 25, 26.
[0025] According to claim 1, in the method of automatic controlling
a self-moving device, especially a vacuum cleaner, with
range-respectively contact-sensors, a closer area around the device
is individually determined and scanned, e.g. by a movable arm, the
device is then moved to a respective new position until no position
can be selected anymore; at this, the determination of the closer
area and the selection of the position is realised mainly on the
basis of the information of the surroundings, which is stored in a
map (vacuuming field) and updated in each step, at this to
determine the respective next position, an optimising out of all
positions, which have been stored and can be approached by the
device, is performed by calculating and comparing for each of these
positions certain evaluation parameters like distances or areas in
the reach of a possible new position, which have not yet been
scanned, and by selecting the position with the best evaluation
result.
[0026] According to claim 2, the scanning of the closer area is
realised, starting with the retracted state of the arm, by repeated
turns to the left and the right with an increased length of the arm
at each turn, until a given maximum arm length is reached and the
arm is then, following a last turn, retracted again.
[0027] The fully automatic method of controlling, especially of
controlling a self moving vacuum cleaner, with range and contact
sensors, which was developed to solve the described problems, shows
the following features:
[0028] Around the device, a closer area is determined, which is
scanned by sensors, and at the borders of this closer area,
possible new positions for the device are stored. Then, after
selection of a position stored in the current or previous step,
dependent on the degree of accessibility, on an assigned priority
and under consideration of the existence of not yet scanned areas
in the range of a possible new position, the selected position is
approached and then the described sequence of steps is repeated
until a given area is completely covered or no new positions can be
selected anymore.
[0029] The floor surface scanned by the sensors is stored in a two
dimensional data field to mark herein by means of certain states
obstacles detected during the scanning, free areas and possible new
positions for the device. This data field, in which successively a
copy of the accessible floor surface with the contours of each
obstacle within and the limiting borders of the floor surface is
generated, is used to determine the controlling parameters for the
device and to control the already covered area.
[0030] Further advantageous possibilities of the method of
controlling are as follows:
[0031] The closer area can be determined by the reach of the
sensors, which are mounted on the device flexibly or stationary. At
this, sensors can be used which are sensitive to direction and
possess distant effect, or simple contact respectively range
sensors, which are guided above the surface which is to be scanned
by a suitable mechanical arrangement. But the scanning of the
closer area can also be performed by emulating the effects of
sensors with distant effect or of flexible sensors by moving the
complete device, so that the device detects the maximum closer area
within reach including potential obstacles with sensors without
distance effect. In this case, any area relative to the position of
the device can be defined as a closer area.
[0032] When using sensors which do not provide any information
about the direction, after the detection of an obstacle its exact
position is determined by consideration of the direction of
detection.
[0033] To limit the number of stored positions, after the scanning
of the closer area, new positions are only stored where no
obstacles have been detected and where no areas border, which have
been already scanned from a previous position of the device. This
condition is realised most simply by storing only new positions at
those borders of the closer area which are marked in the data field
as not yet scanned.
[0034] While storing a point (x, y) into the data field with the
dimensions x_max and y_max, for negative co-ordinates the
transformation into a positive range of co-ordinates, e. g. by
forming x_max-.vertline.x.vertline. respectively
y_max-.vertline.y.vertline. is realised.
[0035] When scanning again an area already marked in the data
field, the states of this area are updated according to the new
sensor data. Thus it is realised, that because of the overlap of
the scanning areas and especially if obstacles are located in an
area already scanned, the stored information about the scanned area
will always be updated.
[0036] When selecting a new position for the device, only such
positions are taken into consideration, which are marked in the
data field as not yet scanned. This criterion provides a simple but
effective method to consider the not yet scanned areas in the range
of a new position: If in the meantime a position is marked as
already scanned since its storage in the data field, it can be
deduced that the surrounding areas as well have been covered
because of the usually compact closer areas. Because of that, such
a position can be deleted, since it does not have to be approached
anymore.
[0037] When storing new positions, different priorities for the
positions can be assigned, e. g. dependent on their location and
nearness in comparison with other positions. When selecting a new
position for the device, only such positions are considered whose
priorities are not inferior to that of a new position already
preliminarily selected in the current step.
[0038] When selecting a new position, only such positions are
considered, which are located within a certain partial area. This
partial area will be modified during the process, if within the
current partial area no new position can be selected. This method
renders possible an indirect influence on the movement of the
device, for instance to ensure that the device mainly covers
coherent areas.
[0039] When selecting a new position, the distance and the
direction from the current position can be used as a criterion of
Valuation.
[0040] Moreover, when selecting a new position for the device, by
evaluating the data field it can guaranteed, that the new position
can be reached by the device on a direct route, allowing only areas
to be traversed which have already been scanned and which are not
marked as an obstacle.
[0041] Furthermore, it is possible when selecting a new position to
consider the covered distance since the storage of a possible new
position, to limit the influence of backlash. This can for instance
be realised by marking as free an additional safety distance at the
borders of the area which is to be traversed, whose width depends
on the covered distance, when checking the possible reach of a
position in the data field.
[0042] After selecting a new position by evaluating the data field,
the shortest route within the already scanned area under avoiding
obstacles is determined and the device is moved along this
route.
[0043] The device can be set back on any previous position and when
setting back the device over several positions, certain positions
in between can be skipped, if a checking of the data field shows
that the device does not have to traverse areas marked as obstacle
during its movement.
[0044] If an unexpected obstacle blocks the movement of the device,
it will detect the contours of the obstacle by scanning it with the
sensors. Since during the movement of the device usually no new
scanning of the route occurs, because at this only areas are
traversed, which are marked as free in the data field, the device
can meet unknown obstacles caused by the movement of objects or
maybe because of backlash. In this case, the movement of the device
is interrupted, the closer area is scanned to update the stored
data, and then a new position is selected.
[0045] After approaching the new position, the new closer area is
determined by evaluating the data field, so that only a small
overlap with already scanned neighboured areas occurs. Especially
advantageous for the use of the invention as a vacuum cleaner is
the fact that during the scanning, at the same time the floor
surface is cleaned.
[0046] To ensure this, the scanning can be realised by a movable
arm, so that not yet scanned areas are always covered at first by
the front end of the arm. When contacting an obstacle, the arm is
guided along the detected obstacle at the smallest possible range.
Especially advantageous can be the selecting of the closer area
around the device in form of the sector of a circle, with the
scanning being performed by repeated turns of the device to the
left and the right with an increased length of the extensible arm
at each turn. To avoid the repeated scanning of the same obstacle,
the arm can be shortened in the range of those angles where an
obstacle has already been detected.
[0047] By evaluating the information in the data field it is
ensured that the cleaning of the floor surface is only conducted in
areas which are marked as not yet cleaned in the data field.
[0048] A device suitable for the methods of the invention, which
besides a suction unit can of course contain other cleaning units,
e. g. for sweeping, cleaning by steam or by spray or which can be
used alternatively for other purposes such as lawn mowing, search
of objects or controlling purposes, shows the following substantial
features, which can be combined:
[0049] The device with propelled wheels and steering wheels
respectively propelling wheels which can be steered and sensors and
an extensible arm is characterised by the fact that apart from two
propelled wheels the lower front end of the arm (head) is used as a
third support, which rests on rollers, balls, wheels or
bristles.
[0050] The device with propelled wheels and steering wheels
respectively propelling wheels which can be steered and sensors and
an extensible arm with a head positioned at its front end is
characterised by one or several rotating circular brushes
positioned at the head.
[0051] The device with propelled wheels and steering wheels
respectively propelling wheels which can be steered and sensors and
an extensible arm is characterised by range or contact sensors at
the arm to detect obstacles, which by moving the arm and turning
the device can cover the closer area and detect obstacles for the
movement of the arm as well as obstacles which only impede the
movement of the device.
[0052] The device with propelled wheels and steering wheels
respectively propelling wheels which can be steered and sensors is
characterised by the fact that the drives are connected elastically
with the respective wheel, e. g. by means of a worm drive, with the
displacement of the drives caused by the blocking of the device by
an obstacle being detected. This feature renders it possible to
renounce on an additional outer contact sensor, which would have to
surround the device completely and which would be mechanically
complicated.
[0053] Additional advantageous features of the device are
characterised as follows:
[0054] The drive of the circular brush(es) is realised via a
movable shaft by a motor which is positioned at the base of the
device.
[0055] Each brush is surrounded by a thick ring of soft bristles
which are adjusted diagonally towards the outer part of the brush
to remove dust from the edges of furniture and to avoid damage.
Moreover, the brush can possess bristles which are adjusted
diagonally towards the inner part of the brush and can solve dirt
from the floor, support the device and in addition to that, are
able to lift the head of the device at small steps e. g. at the
edges of carpets.
[0056] If several circular brushes are used, the axes can be
arranged and propelled so that the brushes move the dirt in the
direction of the suction nozzle beneath the head. Especially
advantageous is an already known arrangement as described in the
German patent application 1057 154, in which the brushes are put
into self rotation by means of a planetary gear while at the same
time circulating under the head.
[0057] Special sensors at the head detect obstacles for the
movement of the arm. A sensor for this purpose can advantageously
be constructed in the form of two electrical conductors positioned
within a short distance to each other around the head of the arm,
of which the outer one is pressed elastically against the inner one
when touching an obstacle, thus closing an electrical circuit.
[0058] Other sensors at the head detect obstacles for the movement
of the device which do not block the arm. For this purpose, a range
sensor can be used which measures the clear height above the head,
using e.g. ultrasonic or electromagnetic waves. Additionally, a
sensor, e. g. in form of a mechanical push button or contact-free,
can detect steps in the floor surface beneath the head to avoid a
tipping over of the device. The movable arm advantageously is
constructed as a telescopic arm with a rectangular profile to
provide, when used as a vacuum cleaner, a big sectional area for
the air stream while constructed as low as possible.
[0059] If the device is not supported at the front end of the arm,
it is advantageous to construct the telescopic arm so that at its
rear end it is mounted rotating around a horizontal axis
respectively vertically flexible to guarantee a good floor contact
of the head. Also in this case, an additional support with an
integrated ball to roll off can be positioned under the front end
of the arm, which allows any lateral movement.
[0060] By shifting of weight, the resting pressure of the head can
be varied.
[0061] After releasing of the blocking sensor, the device is
advantageously placed back until no further blocking is detected by
the sensor. Then follows a repeated advancement, though with
reduced speed, to distinguish between real and fake obstacles. If
the sensor releases the first time because of a real obstacle, it
will release again at reduced speed. If the cause is only a step in
the floor surface which can be overcome, e. g. the edge of a
carpet, or an increased frictional resistance of the brush, the
reduced speed causes a reduction of the dynamic forces and the
frictional forces, thus preventing a new release.
BRIEF DESCRIPTION OF THE DRAWINGS
[0062] By means of the example of a vacuum cleaner, the process of
the method of the invention is explained in detail, while for
better understanding, the construction of the device is described
at first. The method of the invention can of course be applied
independent of the device described in the following and also with
any other suitable device.
[0063] The figures explain the embodiment of the invention as
described in the following, with
[0064] FIG. 1 illustrating the elevation of the vacuum cleaner,
[0065] FIG. 2 illustrating the top plan view of the vacuum
cleaner,
[0066] FIG. 3 illustrating the longitudinal sectional view of the
suction head,
[0067] FIG. 4 illustrating the top plan view of the suction
head,
[0068] FIG. 5 illustrating the driving means with blocking
sensor,
[0069] FIG. 6 illustrating the motion control while vacuuming
sectors,
[0070] FIG. 7 illustrating the sectors of vacuuming when obstacles
occur,
[0071] FIG. 8 illustrating the sequencing of vacuuming sectors,
[0072] FIG. 9 illustrating the storage of the cleaned areas,
[0073] FIG. 10 illustrating the complete flow chart of the
controlling method,
[0074] FIG. 11 illustrating the flow chart `Vacuuming of the sector
ahead`,
[0075] FIG. 12 illustrating the flow chart `Turning of the vacuum
cleaner with possible shortening of the arm`
[0076] FIG. 13 illustrating the flow chart `Extension of the arm
with possible turning of the vacuum cleaner`
[0077] FIG. 14 illustrating the flow chart `Determination of a new
cleaning position`
DETAILED DESCRIPTION FO THE INVENTION
[0078] Driving means and concept of movement
[0079] FIG. 1 shows the elevation of the vacuum cleaner 1 while
FIG. 2 depicts the top plan view upon the lower level of the vacuum
cleaner 1 with removed dust arrester 3.
[0080] The drive is realised by two step motors 9, each of which
propelling by means of a worm drive 24 with a gear reduction of
approx. 1:30 a rubber covered wheel 8. By positioning the wheels 8
on the symmetrical axis of the circular basis, by means of the two
motors 9, as well the forward thrust (same direction of turning) as
the turning around the centre of the vacuum cleaner 1 (opposite
directions of turning) can be realised. As a third support, the
cleaning brush 12 is used, which is mounted at the front end of the
extensible suction arm 4.
[0081] By positioning the comparatively heavy battery 7, which
provides every motor 2, 9, 26 as well as the electronic hardware 5
with energy, on the basis of the cleaner body, it is realised that
the vacuum cleaner 1 is provided with a slight off-balance towards
the front end, so that a stable support of the vacuum cleaner 1 is
always guaranteed.
[0082] This concept on the one hand grants a very simple mechanical
construction, because no additional supporting wheel is necessary,
and on the other hand, the suction brush 12 always is in close
contact to the floor surface, independent of uneven areas of the
floor covering.
[0083] Extensible suction arm with rotating brush
[0084] An essential element of the construction of the vacuum
cleaner 1 is the extensible suction arm 4, see FIG. 1 and 2, which
renders possible the access to not easily accessible areas of the
floor, e. g. under closets or in small niches.
[0085] The suction arm 4 possesses a rectangular profile and
consists mainly of two hollow bodies fitted into each other like a
telescope which are made of synthetic material and through which
the air stream is guided.
[0086] The length of the suction arm 4 is also controlled by a step
motor 9, which drives a toothed rack 10 mounted at the front of the
extensible inner part and which allows an exact positioning.
[0087] At the front end of the arm 4, a rotating suction brush 12
is mounted, which is set rotating by a worm drive 24. The worm
drive 24 is mounted on a shaft 6 with a square profile, on which a
cone shaped cog-wheel 25 can glide while transferring the momenta.
By a suitable support at the outer side and by a second cone shaped
cog-wheel at the inside in an angle of 90.degree., the first cog
wheel is axially fixed at the base of the vacuum cleaner 1. By this
arrangement it is realised that the brush 12 can be turned
independent of the current length of the suction arm 4. Apart from
that, the suction arm 4 can be constructed very flat to clean as
well the floor under low furniture. As a drive for the brush 12, a
commercial geared motor 26 is used, with which a turning frequency
of the brush 12 of about 0.5 Hz is adjusted .
[0088] The cleaning effect is realised by guiding the dust into a
collecting container 3 by means of the brush 12 within the suction
arm 4 and by the air stream which is generated by an electric motor
2 with a power of approx. 50 W.
[0089] The high suction efficiency partly results from the fact
that the even-surfaced and aerodynamic favourable guiding of the
air stream causes only little turbulence and so only small
losses.
[0090] An additional and most important improvement of the cleaning
effect is realised by the cleaning brush 12 which rotates around
its vertical middle axis, and whose longitudinal section is
illustrated in FIG. 3; the position of the section B-B is shown in
FIG. 4. This brush 12 bunches the air stream and loosens dust and
other foreign substances mechanically of the floor, mainly
independent of the kind of floor covering.
[0091] The so-called brush-wheel 27 is connected by an axis 28 with
a cog-wheel above the suction arm 4, in which the worm drive 24,
which is mounted at the end of the shaft 6 with the square profile,
gears in. The brush-wheel 27 is constructed as a Spoke-wheel as to
impede the air stream which is passing through as little as
possible.
[0092] The bristles are all mounted at the outer edge of the
brush-wheel 27, with the bristles 21 which are adjusted diagonally
towards the inner axis being manufactured comparatively stiff and
showing a sufficiently big distance from each other as to let the
air stream pass between them unimpededly; these bristles 21 support
the vacuum cleaner 1 at the front and guarantee that the very soft
bristles 22 which are adjusted diagonally towards the outer side of
the brush just make contact with the floor covering. Apart from the
thus realised decrease of the frictional resistance, an additional
advantage is realised by the fact that the outer bristles 21 are
arranged very densely and that the air stream can only pass through
the cleft to the floor, so that an effective radial jet effect is
produced.
[0093] Optionally, for very soft floor coverings, an additional
support 29 made of synthetic material can be positioned under the
brush-wheel 27 as a lengthening of its own axis to prevent a too
deep sinking of the suction head 11. In this support 29, a roller
ball, which can be turned freely on the floor, is integrated to
minimise the loss because of friction when moving the arm 4, see
FIG. 3.
[0094] The stiff bristles 21 which are adjusted diagonally towards
the inside of the brush have another important task, because they
render possible an uncomplicated transition while passing small
steps in the floor covering, e. g. at the edges of carpets. Here,
the outer soft bristles 22 are pressed towards the inside of the
brush when moving the suction arm 4, with the suction head 11 being
slightly lifted because of the elasticity of the bristles. This
effect is increased by the diagonal adjustment of the inner
supporting-bristles 21, so that the suction arm 4 can glide over
the step.
[0095] The resistance of the bristles when moving the vacuum
cleaner 1 on carpet or over steps also is distinctly decreased by
the vertical turning of the brush 12. The turning frequency has to
be adjusted to the lateral moving speed of the suction head 11 to
guarantee the optimum rolling off of the suction head 11. This
effect is independent of the current direction of moving of the
vacuum cleaner 1 because of the radial symmetry of the brush
12.
[0096] Compared to usual forms of suction heads and suction
brushes, a main advantage of the above described construction lies
in the fact that especially in the direct environment of the
suction head 11, e. g. while vacuuming the edges of furniture and
skirting boards, a high cleaning effect is realised, while damage
is excluded by the use of the soft outer bristles 22.
[0097] Altogether, by combination of all these factors it is
realised that despite of the necessarily limited capacity of the
motor due to the power supply by batteries, the cleaning effect is
much better than that of commercial vacuum cleaners with distinctly
higher connected load.
[0098] Orientation of the vacuum cleaner with sensors
[0099] The orientation of the vacuum cleaner 1 is based on the
calculation of the current suction position by means of the already
covered distance. Because of the exact stepwise steering and the
statistical occurrence of possible mistakes in positioning, a
preciseness of location can be reached, which even after long
distances, covered while vacuum cleaning a room, in combination
with the sensors is absolutely sufficient.
[0100] To detect obstacles with high local precision, the suction
head 11 scans the floor area in front of it by turning the vacuum
cleaner 1 and by an appropriate extension of the arm, see chapter
`Vacuuming of a sector`. At this it is guaranteed by the circular
symmetry of the vacuum cleaner 1, that while the device is turning,
only the suction head 11 can meet an obstacle.
[0101] Altogether, three sensors 13, 14, 15 are required for this
task:
[0102] The most important function falls to the share of the
contact sensor 14 at the suction head 11, whose construction is
illustrated in FIG. 4. This sensor 14 is used for detecting the
touching of obstacles while turning the arm 4 or moving it in a
longitudinal direction.
[0103] It consists mainly of two strips 19, 20 made of synthetic
material, which surround the suction head 11 and are kept within a
distance of only a few millimeters of each other by means of two
lateral distance-blocks 18. While the inner strip 19 is permanently
connected with the suction head 11, the outer strip 20 is supported
only by the distance-blocks 18 and consists of a very thin elastic
synthetic material, to obtain the effect of a soft spring.
[0104] The inner sides of the strips 19, 20, which are turned
towards each other, are covered with a conducting material and
joined by means of connecting wires with the electronic hardware.
Usually, these surfaces, which provide the contacts are isolated
against each other by means of the isolating distance-blocks 18 and
the surrounding air. But if the suction head 11 meets an obstacle,
the outer strip 20 will be pressed against the inner strip 19 so
that an electrical circuit will be closed, at this the direction in
which the obstacle is met is not important.
[0105] The two bulges 23 at both sides of the suction head 11 are
used to reliably detect lateral touches when turning the vacuum
cleaner 1. These bulges 23 convey the lateral pressure on the outer
elastic strip 20, which then is pressed against the inner strip
19.
[0106] FIG. 1 illustrates that the contact sensor 14 covers the
complete height of the suction head 11 and also extends a far way
down to be able to detect possible obstacles, which can block the
movement of the suction head 11.
[0107] Though the contact sensor 14 is not capable to detect the
direction of an obstacle, this information always can be gained
because the direction of the movement of the suction head 11 is
known.
[0108] The second very important sensor is the so called height
sensor 13 at the upper front end of the suction head 11, see FIG. 3
and 4. This sensor 13 has the task to detect obstacles, which do
not impede the suction arm 4 and suction head 11, but whose clear
height is not sufficient for the whole vacuum cleaner 1 to pass
under them.
[0109] For this purpose, a commercial infrared range sensor is
used, whose release range is exactly adjusted to the height of the
vacuum cleaner 1 minus the height of the suction head 11. This
sensor 13 possesses a high lateral accuracy, so that even at
obstacles with a vertical distance of about 30 cm, a lateral local
precision of only a few centimeters is obtained.
[0110] As a third sensor, a so called step sensor 15 is provided,
see FIG. 3, to detect major steps in the floor covering, e. g. at
stairs, to prevent a toppling over of the vacuum cleaner 1.
[0111] This sensor 15 consists of a sensitive switch, which is
mounted shortly behind the suction head 11 at the lower edge of the
suction arm 4, with the distance between sensor 15 and floor
measuring about 1 cm on even surfaces.
[0112] If the suction head 11 is moved over a step with a vertical
downward displacement, which has at least the same distance as
between sensor 15 and floor, the suction arm touches down with the
switch which releases the sensor.
[0113] The sensors 13 to 15 described above are sufficient to be
able to definitely control the vacuum cleaner 1 under normal
conditions with the method described in the chapter `Automatic
controlling of the vacuum cleaner`.
[0114] In spite of that, by moving of objects in areas already
vacuumed, it cannot be excluded, that the vacuum cleaner 1 meets
obstacles when moving.
[0115] To be able to mark an obstacle for the controlling programme
in this case as well, the power transmission from the step motors 9
to the two propelling wheels is endowed with a mechanical blocking
sensor 16 for each wheel.
[0116] To illustrate the function of the blocking sensor 16, one of
the drives 9 is pictured in FIG. 5 in detail, see the position of
the section `A-A` in FIG. 2: The pinion of the step motor 9
transmits its momentum on a cog-wheel which propels a worm drive.
The shaft, on which cog-wheel and worm drive are mounted, is
connected with the mounting support by axial rings so that no axial
movement of the shaft in relation to the mounting support is
possible and so the turning of the shaft is transmitted by means of
the worm drive in the turning of the wheel.
[0117] However, the propelling unit is no rigid system, because the
combined mounting support of shaft and step motor consists of
elastic material, which will permit slight axial displacements of
the shaft, if during the turning of the motor a blocking of the
vacuum cleaner occurs.
[0118] This displacement of the bearing also closes an electrical
contact as illustrated in FIG. 5, which is evaluated by the
controlling electronic hardware.
[0119] The presented realisation of a blocking sensor 16 compared
with rigid systems possesses the advantage, that during a sudden
blocking of the vacuum cleaner, no great forces occur, which could
cause damage, but that because of the elasticity of the mounting
support, a gradual increase of the propelling forces at the shaft
occurs, until the blocking sensor 16 releases.
[0120] By changing the degree of rigidity of the bearing, the
elasticity of the drive can be adjusted individually to the weight
of the vacuum cleaner 1 and the dynamic forces.
[0121] Automatic controlling of the vacuum cleaner
[0122] Description of the controlling method
[0123] The controlling of the vacuum cleaner 1 is realised that,
starting from the current position and in relation to the previous
direction of movement, a sector with a maximum of .+-.90.degree. is
vacuumed in a meandering form, see FIG. 6: At first, the vacuum
cleaner turns into the left maximum position. Then follows a turn
to he maximum right, a lengthening of the suction arm 4 in the size
of the diameter of the suction head, and then the turning back to
the left maximum position. This procedure of movement is repeated
until the suction arm 4 has reached its maximum length, after which
it is drawn back completely when the last turn to the right has
been finished.
[0124] The described controlling of movement is automatically
adjusted, if obstacles occur during the turning or the movement of
the arm, see the chapter `Vacuuming of a sector`. In FIG. 7, a
limited sector area is illustrated, which can be covered by the
suction head 11 if objects impede the movement. Thus, so called
vacuuming shadows may occur, which the suction head 11 cannot reach
because of the blocking of the turning of the suction arm 4.
[0125] Apart from this vacuuming shadows, further free border areas
of the currently vacuumed sector are marked, see next chapter, and
so marked as possible new positions for the vacuum cleaner. Out of
all these positions, after finishing the vacuuming of a sector, the
next vacuuming position is selected and approached, see
`Determination of a new vacuuming position`.
[0126] FIG. 8 illustrates by means of the example of the corner of
a room, how by concatenating single vacuuming sectors, areas with
any contour can be cleaned completely (in this example all sectors
possess the maximum opening angle of 180.degree.). By means of
overlapping the sectors, some areas are cleaned several times,
which additionally increases the cleaning effect and compensates
possible inaccuracies of the position of the vacuum cleaner.
[0127] To increase the reach of the vacuum cleaner with one charge
of the batteries, the suction engine, which is the biggest consumer
of power, runs only while vacuuming a sector and not when a new
vacuuming position is approached.
[0128] Marking of the cleaned areas
[0129] For the global orientation of the vacuum cleaner, the whole
area which is to be cleaned is mapped in an electronic data field,
the so called vacuuming field, wherein the different states which
can be assigned to an area element are stored. This two dimensional
information is used to mark new cleaning positions, to determine
the route to these positions and for the determination of the
vacuuming sector.
[0130] The following four states can be distinguished:
[0131] State 0: "unvacuumed"
[0132] This state is the default-value in the cleaning field when
starting the vacuum cleaner and is overwritten as soon as the
suction head has covered the respective place for the first
time.
[0133] State 1: "vacuumed"
[0134] This state is assigned to all area elements of the vacuuming
field, which have already been covered by the suction head and
which do not present an obstacle for the movement of the vacuum
cleaner.
[0135] State 2: "obstacle"
[0136] This state is used to mark obstacles, which have been
detected by the sensors. A field marked with this state cannot be
traversed by the vacuum cleaner when approaching a new cleaning
position.
[0137] State 3: "possible new cleaning position"
[0138] With this state, while cleaning a sector, a border field,
which before must exhibit the state 0, is marked as a possible new
cleaning position. If the area later on is covered by the suction
head, the field will obtain the state 1 or 2. When controlling a
possible new vacuuming position, state 3 shows that the respective
area has not been vacuumed before.
[0139] To map the real area which has to be cleaned in the
vacuuming field, a two-dimensional screen is used. At this, the
local precision in x- or y- direction amounts to 1 cm each and thus
is sufficiently exact for the precision of detection of the
sensors. Since for the four different states only two bits are
necessary, it is possible to map with this resolution an area of
10.times.10m.sup.2 into a memory size of only 250 kBytes.
[0140] A possible problem when minimising the storing requirements
is caused by the fact that at the beginning of the cleaning
procedure, the vacuum cleaner is started at any place of the room.
From this origin, for x and y may occur positive as well as
negative co-ordinates, while the latter cannot be taken over
directly into the vacuuming field. To solve this problem, a
transformation of co-ordinates is carried out, see FIG. 9:
[0141] Each negative value for x respectively y is mapped on
xmax-.vertline.x.vertline. respectively ymax-.vertline.y.vertline.,
with xmax and ymax defining the maximum dimensions of the vacuuming
field for x and y, which limit the range of movement of the vacuum
cleaner.
[0142] Because of the transformation, field areas with at least one
negative co-ordinate, are mapped in a shifted way in the vacuuming
field.
[0143] During control of the movement, it is supervised that the
amount of the maximum positive and the maximum negative vacuuming
distance from the origin in the directions x and y does not exceed
the given values for xmax or ymax. If this is not the case, the
processing of the program will be interrupted with an error
message. Since the suction head moves rather continuously, new
states in the cleaning field will always be assigned if a distance
of 1 cm has been covered. This includes that the areas below the
outer radius of the suction head are taken into account in the form
of a semi-circle in relation to the respective direction of
movement of the head.
[0144] An exception of this rule of marking is made for the sensors
for height and steps: If these sensors detect an obstacle, only the
area in the vacuuming field which is positioned directly under the
respective sensor, will be marked.
[0145] Description of the controlling method
[0146] In the flow charts described in the following, the following
notation is used for the illustration: Beginning and end
respectively jumping back to the previous flow chart are marked by
a circle. Actions are symbolised by rectangles, with symbols marked
by shadows meaning that the respective action is detailed in a
separate flow chart. Hexagons with two lateral peaks have the
meaning of a decision with the two possibilities `yes` and
`no`.
[0147] The complete flowchart of the vacuum cleaner control is
depicted in FIG. 10.
[0148] At the beginning of the vacuuming process and always when a
new vacuuming position is taken, the current vacuuming position is
stored. For a definite localisation, the x- and y-coordinates of
the centre point of the vacuum cleaner, the length of the suction
arm and the angle, which the suction arm takes in relation to the
x-axis, are required.
[0149] Then, the optimum size of the sector to be vacuumed within
the maximum borders of the angle of .+-.90.degree.(proceeding from
the previous direction of movement of the vacuum cleaner) and the
maximum possible length of the suction arm Rmax, are
determined.
[0150] For this, it is checked in the vacuuming field, which points
still show the state 0, meaning unvacuumed. The area in which these
points can be found is marked definitely by the left and the right
limiting angle Wl and Wr and the outer- and inner radius Ra and Ri,
with Ri meaning the constant length of the arm when retracted.
[0151] In the next step, the so defined area of the sector is
vacuumed, see section "Vacuuming of a sector", including a
respective treatment of obstacles. Every area which is covered, is
marked in the cleaning field with the state 1 respectively if an
obstacle was detected with state 2.
[0152] Now possible new positions of the suction head (tasks) are
marked with the state 3 in the vacuuming field as possible starting
points for new vacuuming sectors at the free outer borders of the
vacuumed area, which are marked by the state 0. In addition to this
marking, the storage of each task is carried out with its
co-ordinates, its priority and the optimum new direction of
vacuuming (rectangular to the respective border) in the list of the
still open tasks.
[0153] If the vacuum cleaner could be turned to Wl respectively Wr
as well as at the vacuuming shadows behind obstacles, the corners
will be marked as possible new vacuuming positions. Apart from the
lateral borders, the centre of each free border area (marked by the
fact that the arm can be extended to Ra without contacting an
obstacle) is marked. To increase the number of possible vacuuming
positions at larger free border areas, apart from the centre
additional border points are marked, though with the lower priority
2. In FIG. 6, the possible new vacuuming positions in case of a
sector without obstacles, and in FIG. 7 in case of a sector with
obstacles, are depicted as black arrows (prio 1) respectively as
white arrows (prio 2), with the arrowheads illustrating the new
direction of vacuuming. The current position of the suction head,
from which the last sector was vacuumed, now is deleted from the
list of still open tasks.
[0154] Then, the position for the vacuuming of the next sector is
determined out of all stored tasks and the vacuum cleaner is moved
with its head to this point, see chapter "Determination of the next
vacuuming sector".
[0155] If no new vacuuming position could be found and approached,
the cleaning process will be ended; if this is not the case, it
will be continued with the storage of the new vacuuming position as
described above.
[0156] Vacuuming of a sector
[0157] While vacuuming the current sector, whose borders were
determined after the approaching of a new position, the method
described in the following with its route optimised controlling of
the suction head allows the exact scanning of the contours of any
object which impedes the movement of the suction arm.
[0158] If no obstacles are detected during the sector vacuuming,
the movement of the suction head will be carried through as in FIG.
6 illustrated. But if the suction head meets an obstacle while
turning or changing the length, it is guided along the obstacle at
a close range.
[0159] To be able to guide the suction head along already known
obstacles and to avoid a multiple detection, the so called
angle-field is used, which is initiated anew before each vacuuming
of a sector and is used to store the respective maximum radius for
each angle of the sector.
[0160] At the beginning of the sector vacuuming, the desired radius
Rs, which provides the reference length for the suction arm and
which is incremented after each turning, is set at the inner radius
Ri, which the suction arm takes in its retracted state.
[0161] Now, the suction arm is turned towards the left border of
the sector Wl, at the most though until meeting an obstacle,
afterwards the turning direction is changed.
[0162] Then follows the turning of the vacuum cleaner into the
current direction with possible shortening of the length of the
arm, see next chapter and FIG. 12. During this procedure, if the
determined final angle cannot be reached directly because of an
obstacle, it will be tried to continue the turning by shortening
the length of the arm step by step while detecting the border
contour of the obstacle. The turning is finished as soon as the
suction arm reaches the final angle respectively if it can be
turned freely the next step after a necessary shortening of the
arm, because then the arm at first has to be lengthened again to
follow the contour of the obstacle.
[0163] After this, it is checked, if after finishing the turning
process the respective sector border could be reached, respectively
if all angles up to the sector border are marked with an radius
shorter than the current desired radius. Only if at least one of
these conditions is fulfilled, the direction of turning will be
converted, Rs will be increased by the diameter of the suction head
and it will be checked, if Rs is larger than the previously
determined outer radius Ra. Since in this case, the outer border of
the sector was reached, the suction motor is stopped, the suction
arm is retracted to Ri and the vacuuming process is continued as
described in FIG. 10 and section "Description of the controlling
method".
[0164] If this criterion of breaking off is not fulfilled, in the
following it is tried to extend the suction arm to Rs, see section
"Extension of the arm with possible turning of the vacuum cleaner"
and FIG. 13. At this, in case of contact with an obstacle, the
turning is continued step by step and then it is tried anew to
reach Rs.
[0165] This macro ends with reaching Rs respectively if the
evaluation of the angle-fields reveals that in the direction of the
turning, all accessible areas have already been vacuumed.
[0166] Then, it is jumped back to the macro "Turning of the vacuum
cleaner with possible shortening of the arm", as described
above.
[0167] Turning of the vacuum cleaner with possible shortening of
the arm
[0168] As illustrated in FIG. 12, at first the final angle of the
turning is calculated, which generally is not identical with the
left or right border angle Wl respectively Wr. For this, it is
checked if at a previous turn in this direction with a shorter
length of the arm an obstacle has already been detected. In this
case, a too large turning angle would cause the suction arm to meet
an already known obstacle again, though not with the suction head
an the here mounted contact sensor, but further behind. The
obstacle then could only be detected by the blocking sensor, which
releases at distinctly greater forces when pressed against an
obstacle than the contact sensor and which is not planned for this
use (see "Orientation of the vacuum cleaner with sensors").
[0169] If after completing of the turning the borders of the
sectors Wl respectively Wr have been reached, meaning that no
obstacle has occurred, an instant jumping back to FIG. 11 is
performed, see the previous section. The jumping back also will be
performed if the turning is stopped because of a known obstacle,
which reaches up to the border of the sector, because then a
continuing of the turning with the current desired radius behind
the obstacle is not possible.
[0170] If both conditions are not fulfilled, the suction head will
be turned back by 1 cm and then the arm is retracted, while it is
distinguished between two cases:
[0171] If an obstacle which is already known but can be
circumvented exists, meaning that the turning can be continued
behind the obstacle with the desired radius, the arm will be
retracted far enough and turned before the obstacle. After this,
the jumping back to the previous flowchart is performed. If the
obstacle is detected with the current desired radius for the first
time, its contour will have to be scanned exactly to be able to
vacuum the edges at best. Because of that, in this case the length
of the arm is shortened only by 1 cm and then it is tried to turn
on the head for half the width of the head (though the borders of
the sector here form an absolute limit).
[0172] The radiuses of the suction arm in the covered angles are
then stored in the angle-field.
[0173] If the suction arm could be turned half the width of the
head without meeting again the obstacle or if the respective border
of the sector was reached, it will be jumped back to FIG. 11. If
the sensors detect a new obstacle, it will again be checked if a
continuing is possible as described above.
[0174] Extension of the arm with possible turning of the vacuum
cleaner
[0175] At first it is tried as illustrated in FIG. 13, to extend
the suction arm to the current desired angle Rs. The arm is turned
back after finishing the extension of the arm against the current
direction of turning for at most half the width of the head until
the obstacle is met. Since when circumventing an obstacle the
turning is performed in multiples of half the width of the head,
the turning back is necessary to assure that the contour of the
obstacle which has to be circumvented is detected exactly. The
turning back has to be performed only if before no change of the
turning direction has occurred and even then would only be
performed if the suction arm can be extended a certain minimum
length.
[0176] Then, it will be checked if the desired radius has been
reached or if in the angle-field already all following angles in
the turning direction are marked with an radius smaller than Rs,
thus marking a known obstacle until the border of the sector. In
both cases, it is jumped back to FIG. 11.
[0177] If a known obstacle lies within the turning direction which
does not reach up to the border of the sector, the suction arm then
will be retracted as far as necessary, turned past the obstacle and
then it will be tried again to extend the arm.
[0178] If this is not possible, the suction arm will be retracted
slightly until no obstacle is detected anymore by the sensor and
turned on half the width of the head. If because of an obstacle no
turn has been possible, the jumping back to FIG. 11 will be
performed.
[0179] If the arm could be turned at least slightly, the covered
area in the angle-field would be marked with the respective
radiuses, and then follows the jumping back to the extension of the
suction arm as described above.
[0180] Determination of the next vacuuming position
[0181] The main principle to determine the new vacuuming position
consist in filtering the optimum task of the current position out
of all the open tasks by evaluating different criteria. If no new
task is found from the current position, the previous positions of
the vacuum cleaner will be examined one after another. If from one
of these previous positions, a new vacuuming position can be
determined, the vacuum cleaner will be led back to this position,
and from there, the new position is approached.
[0182] At the beginning of the flow chart in FIG. 14, the test
position is set on the current position of the vacuum cleaner.
Then, all the stored tasks will be run through and checked if they
are suitable as a possible continuing step.
[0183] The following evaluations in the here mentioned sequence are
performed:
[0184] At first, by means of the state in the vacuuming field it
will be checked, if the stored position has been already vacuumed.
In this case, the respective task is rejected and deleted.
[0185] If a possible candidate for the new position has already
been chosen, only such tasks will be evaluated, which show at least
the same priority, see chapter "Description of the controlling
method". If this condition is fulfilled, then the distance of the
task from the current test position will be calculated and by means
of the states in the cleaning field, it will be checked, if the
vacuum cleaner with its head can be moved to this position on a
direct route. For this, the whole route which has to be covered by
the vacuum cleaner has to be marked with the state 1 and it has to
be possible that the task can be reached at least by extending the
arm.
[0186] Of all positions which can be approached, that one is
selected, whose priority is higher than the one of the priorities
already selected, or which possesses a higher value if the x
co-ordinate if the priorities are equal. By this criterion it is
guaranteed that the area which is to be cleaned always is cleaned
from back to front.
[0187] If after checking all stored tasks, no approachable position
could be found, the test position will be set back on the
respective previous position of the vacuum cleaner, from where
again a loop over all tasks is performed.
[0188] If from none of the former positions of the vacuum cleaner a
continuing is possible, either because all of the tasks have been
accomplished or because the still open tasks cannot be reached by
the vacuum cleaner, the vacuuming process will break off.
[0189] If this is not the case, it will be checked, if the test
position, from where a task has been found, is identical to the
current position of the vacuum cleaner. While in this case, the new
position can be approached directly after the turning of the vacuum
cleaner in the respective direction, in all other cases, the vacuum
cleaner has to be set back to the test position at first.
[0190] At this, during several operations of setting-back which
have to be carried through, an optimising of the route is performed
by checking for each position in between, if it can be skipped and
if the vacuum cleaner possibly can be moved back directly from its
current position to the position from which then is taken the new
vacuuming position. Condition for a possible "short-cut"again is
the fact that the vacuum cleaner only may traverse areas, which are
marked in the vacuuming-field with the state 1 to avoid a collision
with obstacles.
LIST OF REFERENCE NUMBERS
[0191] 1 vacuum cleaner
[0192] 2 suction engine
[0193] 3 dust arrester/collecting container
[0194] 4 suction arm
[0195] 5 electronic hardware
[0196] 6 shaft
[0197] 7 battery
[0198] 8 wheel
[0199] 9 step motor
[0200] 10 toothed rack
[0201] 11 suction head
[0202] 12 brush
[0203] 13 height sensor
[0204] 14 contact sensor
[0205] 15 step sensor
[0206] 16 blocking sensor
[0207] 17 bearing
[0208] 16 distance-block
[0209] 19 inner sensor strip
[0210] 20 outer sensor strip
[0211] 21 inner bristles
[0212] 22 outeer bristles
[0213] 23 bulge
[0214] 24 worm drive
[0215] 25 cog-wheel
[0216] 26 geared motor
[0217] 27 brush wheel
[0218] 28 axis
[0219] 29 support
[0220] 30 pinion
[0221] 31 elastic mounting support
[0222] 32 axial ring
* * * * *