U.S. patent application number 12/813871 was filed with the patent office on 2010-12-16 for robot cleaner and method of controlling traveling thereof.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Woo Ram Chung, Jun Pyo Hong, Sam Jong Jeung, Jae Man Joo, Dong Won Kim, Jang Youn Ko, Jun Hwa LEE, Jeong Gon Song, Kyung Hwan Yoo.
Application Number | 20100313910 12/813871 |
Document ID | / |
Family ID | 42646316 |
Filed Date | 2010-12-16 |
United States Patent
Application |
20100313910 |
Kind Code |
A1 |
LEE; Jun Hwa ; et
al. |
December 16, 2010 |
ROBOT CLEANER AND METHOD OF CONTROLLING TRAVELING THEREOF
Abstract
Disclosed herein are a robot cleaner that has an improved
traveling performance, and a method of controlling traveling
thereof. The robot cleaner allows driving wheels, which move the
robot cleaner, and a brush unit, which sweeps dust on a floor, to
be rotated in the same direction.
Inventors: |
LEE; Jun Hwa; (Suwon-si,
KR) ; Joo; Jae Man; (Suwon-si, KR) ; Jeung;
Sam Jong; (Gwangju, KR) ; Song; Jeong Gon;
(Gwangju, KR) ; Kim; Dong Won; (Hwaseong-si,
KR) ; Hong; Jun Pyo; (Suwon-si, KR) ; Ko; Jang
Youn; (Gwangsan-Gu, KR) ; Chung; Woo Ram;
(Seoul, KR) ; Yoo; Kyung Hwan; (Incheon-si,
KR) |
Correspondence
Address: |
STAAS & HALSEY LLP
SUITE 700, 1201 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon
KR
|
Family ID: |
42646316 |
Appl. No.: |
12/813871 |
Filed: |
June 11, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61186529 |
Jun 12, 2009 |
|
|
|
Current U.S.
Class: |
134/6 ;
15/21.1 |
Current CPC
Class: |
A47L 7/02 20130101; A47L
2201/06 20130101; A47L 2201/04 20130101; A47L 9/0411 20130101; A47L
2201/00 20130101 |
Class at
Publication: |
134/6 ;
15/21.1 |
International
Class: |
B08B 7/00 20060101
B08B007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 26, 2009 |
KR |
10-2009-79131 |
Claims
1. A robot cleaner, comprising: a main body; a plurality of driving
wheels to move the main body; a brush unit rotated to sweep dust on
a floor; and a control unit to control the brush unit to be rotated
in a same direction as rotation of the driving wheels, when the
main body travels backward.
2. The robot cleaner according to claim 1, further comprising: a
brush motor to rotate the brush unit in a forward or reverse
direction; and a plurality of driving motors to rotate the driving
wheels in the forward or reverse direction, wherein the control
unit controls the driving wheels and the brush unit to be rotated
in the same direction.
3. The robot cleaner according to claim 2, wherein the control unit
controls forward and backward traveling of the main body by
changing the rotating direction of the brush unit according to
change of the rotating direction of the driving wheels.
4. The robot cleaner according to claim 3, wherein the control unit
controls the brush motor such that the brush motor is rotated at a
relatively high speed in an initial stage when the rotating
direction of the brush unit starts to be changed, and the rotating
speed of the brush motor is reduced when the rotating direction of
the brush unit has been changed.
5. A robot cleaner comprising: a main body; a plurality of driving
wheels to move the main body; a brush unit rotated to sweep dust on
a floor; and a control unit to control the brush unit to be rotated
in a same direction as rotation of the driving wheels according to
a state of the floor, when the main body travels backward.
6. The robot cleaner according to claim 5, further comprising a
floor surface sensor to sense the state of the floor, the state of
the floor including a resistance, wherein the control unit controls
the brush unit to be rotated in the same direction as the driving
wheels, if the floor has a high resistance.
7. The robot cleaner according to claim 5, further comprising a
plurality of driving sensors to sense movement of the driving
wheels, wherein the control unit controls the brush unit to be
rotated in the same direction as the driving wheels, if no movement
of the driving wheels is sensed by the driving sensors.
8. The robot cleaner according to claim 5, further comprising
driving motors to rotate the driving wheels in a forward or reverse
direction, and a load sensor to sense a load applied to the driving
motors, wherein the control unit controls the brush unit to be
rotated in the same direction as the driving wheels, if the sensed
load is greater than a reference value.
9. A method of controlling traveling of a robot cleaner, the method
comprising: detecting a rotating direction of driving wheels that
move the robot cleaner; determining a rotating direction of a brush
unit according to the rotating direction of the driving wheels; and
moving the robot cleaner forward or backward comprising rotating
the driving wheels and the brush unit in the same direction
according to the determined rotating direction of the brush
unit.
10. The method according to claim 9, wherein the determining the
rotating direction of the brush unit comprises changing the
rotating direction of the brush unit into a direction to allow the
robot cleaner to smoothly travel forward when the driving wheels
are rotated in the forward direction.
11. The method according to claim 9, wherein the determining of the
rotating direction of the brush unit comprises changing the
rotating direction of the brush unit into a direction to allow the
robot cleaner to smoothly travel backward when the driving wheels
are rotated in the backward direction.
12. The method according to claim 9, further comprising sensing a
resistance of a floor, wherein, the determining of the rotating
direction of the brush unit comprises changing the rotating
direction of the brush unit into the same direction as the rotating
direction of the driving wheels, if the floor has a high
resistance.
13. The method according to claim 9, further comprising sensing
movement of the driving wheels, wherein, the determining of the
rotating direction of the brush unit comprises changing the
rotating direction of the brush unit to the same direction as the
rotating direction of the driving wheels, if no movement of the
driving wheels is sensed.
14. The method according to claim 9, further comprising sensing a
load applied to the driving wheels, wherein, the determining of the
rotating direction of the brush unit comprises changing the
rotating direction of the brush unit into the same direction as the
rotating direction of the driving wheels, if the load is greater
than a reference value.
15. The method according to claim 9, further comprising controlling
the brush unit such that the brush unit is rotated at a relatively
high speed in an initial stage when the rotating direction of the
brush unit starts to be changed, and reducing the rotating speed of
the brush motor when the rotating direction of the brush unit has
been changed.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Patent Ser. No.
61/186,529, filed on Jun. 12, 2009 in the USPTO and Korean Patent
Application No. 2009-0079131, filed on Aug. 26, 2009 in the Korean
Intellectual Property Office, the disclosures of which are
incorporated herein by reference.
BACKGROUND
[0002] 1. Field
[0003] Embodiments relate to a robot cleaner that has an improved
traveling performance, and a method of controlling traveling
thereof.
[0004] 2. Description of the Related Art
[0005] In general, a robot cleaner is an apparatus that sucks
foreign substances, such as dust, from a floor while traveling on
its own in a region to be cleaned without user manipulation, and
thus performs a cleaning operation.
[0006] In such a robot cleaner, a pair of driving wheels is
installed at both sides of the lower portion of a main body, and
causes the main body to move forward or backward or to be rotated.
The robot cleaner easily moves forward or backward on a hard floor,
such as a wooden floor or an oilpaper floor. However, on a floor,
such a carpet, resistance is high due to wool (or other fabric) and
thus the robot cleaner cannot easily move forward or backward.
Particularly, while the robot cleaner performs a cleaning operation
by rotating a brush unit in one direction (forward moving
direction), forward movement is easy due to the rotation of the
brush unit in the forward moving direction. However, backward
movement is difficult. In order to perform forward or backward
movement, the driving wheels change a rotating direction thereof
into the forward or backward direction, but the brush unit is
uniformly rotated in the forward moving direction. Therefore, in
order to perform backward movement, the robot cleaner requires the
higher force, and if resistance is too great, the robot cleaner may
not move backward.
SUMMARY
[0007] Accordingly, it is an aspect to provide a robot cleaner that
has an improved traveling performance such that forward and
backward movement is smoothly carried out on a floor having a high
resistance, such as a carpet, and a method of controlling traveling
thereof.
[0008] Additional aspects will be set forth in part in the
description which follows and, in part, will be apparent from the
description, or may be learned by practice of the invention.
[0009] The foregoing and/or other aspects are achieved by providing
a robot cleaner including a main body, a plurality of driving
wheels to move the main body, a brush unit rotated to sweep dust on
a floor, and a control unit to control the brush unit to be rotated
in a same direction as rotation of the driving wheels, when the
main body travels backward.
[0010] The robot cleaner may further include a brush motor to
rotate the brush unit in a regular or reverse direction, and
driving motors to rotate the driving wheels in the regular or
reverse direction, and the control unit may control the driving
wheels and the brush unit to be rotated in the same direction.
[0011] The control unit may control forward and backward traveling
of the main body by changing the rotating direction of the brush
unit according to change of the rotating direction of the driving
wheels.
[0012] The control unit may control the brush motor such that the
brush motor is rotated at a relatively high speed in an initial
stage when the rotating direction of the brush unit starts to be
changed, and the rotating speed of the brush motor is relatively
reduced when the rotating direction of the brush unit has been
changed.
[0013] The foregoing and/or other aspects are achieved by providing
a method of controlling traveling of a robot cleaner including a
main body, a plurality of driving wheels to move the main body, a
brush unit rotated to sweep dust on a floor, and a control unit to
control the brush unit to be rotated in a same direction as
rotation of the driving wheels according to a state of the floor,
when the main body travels backward.
[0014] The robot cleaner may further include a floor surface sensor
to sense the state of the floor, and the control unit may control
the brush unit to be rotated in the same direction as rotation of
the driving wheels, if the floor has a high traveling
resistance.
[0015] The robot cleaner may further include driving sensors to
sense movement of the driving wheels, and the control unit may
control the brush unit to be rotated in the same direction as
rotation of the driving wheels, if no movement of the driving
wheels is sensed by the driving sensors.
[0016] The robot cleaner may further include driving motors to
rotate the driving wheels in a regular or reverse direction, and a
load sensor to sense a load applied to the driving motors, and the
control unit may control the brush unit to be rotated in the same
direction as rotation of the driving wheels, if the load is greater
than a reference value.
[0017] The foregoing and/or other aspects are achieved by providing
a method of controlling traveling of a robot cleaner, the method
including detecting a rotating direction of driving wheels that
move the robot cleaner, determining a rotating direction of a brush
unit according to the rotating direction of the driving wheels, and
moving the robot cleaner forward or backward including rotating the
driving wheels and the brush unit in the same direction according
to the determined rotating direction of the brush unit.
[0018] In the determination of the rotating direction of the brush
unit, the rotating direction of the brush unit may be changed into
a direction to allow the robot cleaner to smoothly travel forward
when the driving wheels are rotated in a forward traveling
direction of the robot cleaner.
[0019] In the determination of the rotating direction of the brush
unit, the rotating direction of the brush unit may be changed into
a direction to allow the robot cleaner to smoothly travel backward
when the driving wheels are rotated in a backward traveling
direction of the robot cleaner.
[0020] The method may further include sensing a state of a floor,
and in the determination of the rotating direction of the brush
unit, the rotating direction of the brush unit may be changed into
the same direction as the rotating direction of the driving wheels,
if the floor has a high traveling resistance.
[0021] The method may further include sensing movement of the
driving wheels, and in the determination of the rotating direction
of the brush unit, the rotating direction of the brush unit may be
changed into the same direction as the rotating direction of the
driving wheels, if no movement of the driving wheels is sensed.
[0022] The method may further include sensing a load applied to the
driving wheels, and in the determination of the rotating direction
of the brush unit, the rotating direction of the brush unit may be
changed into the same direction as the rotating direction of the
driving wheels, if the load is greater than a reference value.
[0023] The method may further include controlling the brush unit
such that the brush unit is rotated at a relatively high speed in
an initial stage when the rotating direction of the brush unit
starts to be changed, and the rotating speed of the brush motor is
relatively reduced when the rotating direction of the brush unit
has been changed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] These and/or other aspects will become apparent and more
readily appreciated from the following description of the
embodiments, taken in conjunction with the accompanying drawings of
which:
[0025] FIG. 1 is a top perspective view of a robot cleaner in
accordance with one embodiment;
[0026] FIG. 2 is a bottom perspective view of the robot cleaner in
accordance with the embodiment;
[0027] FIG. 3 is a bottom view of the robot cleaner in accordance
with the embodiment;
[0028] FIG. 4 is a perspective view of a brush unit in accordance
with the embodiment;
[0029] FIG. 5 is a control block diagram of the robot cleaner in
accordance with the embodiment;
[0030] FIG. 6 is a flow chart illustrating a method of controlling
traveling of the robot cleaner in accordance with the
embodiment;
[0031] FIG. 7 is a schematic view illustrating rotating directions
of driving wheels and the brush unit when the robot cleaner in
accordance with the embodiment travels forward; and
[0032] FIG. 8 is a schematic view illustrating rotating directions
of the driving wheels and the brush unit when the robot cleaner in
accordance with the embodiment travels backward.
DETAILED DESCRIPTION
[0033] Reference will now be made in detail to the embodiments,
examples of which are illustrated in the accompanying drawings,
wherein like reference numerals refer to like elements
throughout.
[0034] FIG. 1 is a top perspective view of a robot cleaner in
accordance with one embodiment, FIG. 2 is a bottom perspective view
of the robot cleaner in accordance with the embodiment, FIG. 3 is a
bottom view of the robot cleaner in accordance with the embodiment,
and FIG. 4 is a perspective view of a brush unit in accordance with
the embodiment.
[0035] As shown in FIGS. 1 to 4, a robot cleaner 1 in accordance
with this embodiment includes a main body 10 forming the external
appearance of the robot cleaner 1, a driving device 20 installed at
the lower portion of the main body 10 to move the robot cleaner 1,
and brush devices 30 and 40 to sweep or disperse dust on a floor,
on which the robot cleaner 1 travels, to clean the floor.
[0036] Further, a contact sensor and a proximity sensor together
with the driving device 20 and the brush devices 30 and 40 may be
installed on the main body 10. For example, a bumper 11 installed
on the front portion of the main body 10 is used to sense an
obstacle, such as a wall, and an infrared sensor (or an ultrasonic
sensor) installed on the bottom of the main body 10 is used to
sense an obstacle, such as a stair. The main body 10 may further
include a display device 12 to inform a user of data regarding the
state or operation of the robot cleaner 1.
[0037] The driving device 20 includes a pair of driving wheels 21
and 22 installed at both sides of the central portion of the main
body 10 to adjust movement of the robot cleaner 1, and a caster
wheel 23 installed at the front portion of the main body 10 such
that the rotating angle of the caster wheel 23 is changed according
to the state of the floor, on which the robot cleaner 1 moves. The
caster wheel 23 is used to stabilize the posture of the robot
cleaner 1 or to prevent the robot cleaner 1 from falling, and thus
supports the robot cleaner 1. The caster wheel 23 is a wheel in the
shape of a roller or a caster.
[0038] Both driving wheels 21 and 22 are respectively rotated in
forward or backward directions according to instructions of a
control unit, which will be described later, and thus cause the
robot cleaner 1 to move forward or backward or to be rotated. For
example, the robot cleaner 1 moves forward or backward by rotating
the driving wheels 21 and 22 in the forward or backward direction.
Further, the robot cleaner 1 is rotated in the left direction, as
seen from the front part, by rotating the right driving wheel 22 in
the forward direction while rotating the left driving wheel 21 in
the backward direction, and the robot cleaner 1 is rotated in the
right direction, as seen from the front part, by rotating the
driving wheels 21 and 22 in the reverse directions,
respectively.
[0039] The brush devices 30 and 40 include a main brush device 30
provided adjacent to a suction hole 14 formed through the bottom
surface of the main body 10 and used to sweep and disperse dust on
the floor to improve dust suction efficiency, and side brush
devices 40 installed at both sides of the front portion of the
bottom surface of the main body 10 to sweep the dust on the floor,
on which the robot cleaner 1 travels, toward the suction hole
14.
[0040] The main brush device 30 includes a brush unit 31 formed in
a drum shape, having a length corresponding to that of the suction
hole 14, disposed horizontally adjacent to the suction hole 14 and
rotated against the floor in a roller type to sweep or disperse
dust accumulated on the floor, and a brush motor 32 to rotate the
brush unit 31 in the forward or backward moving direction.
[0041] Further, the brush unit 31 includes a roller 33 and brushes
34. The roller 33 is made of a rigid body, rotatably connected to
the main body 10, and is driven by the brush motor 32. An end cap
33a is installed at each of both side ends of the roller 33, and
prevents foreign substances from moving to the brush motor 32. The
brushes 34 are made of an elastic material and are implanted in the
roller 33. The brushes 34 are driven together with the roller 33
during traveling of the robot cleaner 1, and agitate foreign
substances, such as dust, accumulated on the floor.
[0042] The brush unit 31 may further include flaps 35 made of an
elastic material. The plural flaps 35 are installed in the
lengthwise direction of the roller 33, and are separated from each
other by designated intervals. The flaps 35 serve to increase a
diameter of the roller 33, on which foreign substances, such as
hair, are wound, and minimizes frictional force of the foreign
substances with the roller 33. That is, the flaps 35 prevent the
foreign substances from being wound directly on the roller 33 and
allow the foreign substance to be wound on the flaps 35, thereby
minimizing frictional force of the foreign substances with the
roller 33 and reducing energy required to remove the foreign
substances from the roller 33.
[0043] The side brush devices 40 are respectively installed at both
sides of the front portion of the bottom of the main body 10 at a
designated interval, and each of the side brush devices 40 includes
a side brush 41 rotated horizontally relative to the floor to sweep
dust accumulated on the floor, on which the robot cleaner 1
travels, toward the suction hole 14.
[0044] The robot cleaner 1 in accordance with this embodiment
further includes a dust collector to inhale foreign substances,
such as dust, using suction force, and to store the inhaled foreign
substances.
[0045] FIG. 5 is a control block diagram of the robot cleaner 1 in
accordance with the embodiment. The robot cleaner 1 further
includes a sensor unit 100 to sense various data regarding the
robot cleaner 1 and a floor, on which the robot cleaner 1 travels,
a control unit 110 to control rotating direction and speed of the
brush unit 31 in connection with rotating directions (forward and
backward directions) of the driving wheels 21 and 22 according to
data sensed by the sending unit 100, and driving motors 120 to
respectively drive the driving wheels 21 and 22 in the forward or
backward moving direction according to driving instructions of the
control unit 110.
[0046] The sensor unit 100 includes driving sensors 102 to sense
movement of the driving wheels 21 and 22, a floor surface sensor
104 to sense a state of the floor, on which the robot cleaner 1
travels, and a load sensor 106 to sense loads applied to the
driving motors 120.
[0047] The driving sensors 102 sense all data regarding the driving
of the driving wheels 21 and 22, such as rotating directions and
rotating speeds of the respective driving wheels 21 and 22 and
torques transmitted to the respective driving wheels 21 and 22.
[0048] The floor surface sensor 104 senses whether or not the
floor, on which the robot cleaner 1 travels, is a hard floor, such
as a wooden floor or an oilpaper floor, or a cushiony floor having
a high traveling resistance, such as a floor provided with a
carpet, and transmits the sensed data to the control unit 110.
[0049] The load sensor 106 senses loads (a torque or a current
value) applied to the driving motors 120, and transmits the sensed
loads to the control unit 110.
[0050] Hereinafter, the operating process and effects of a method
of controlling traveling of the above-described robot cleaner will
be described
[0051] FIG. 6 is a flow chart illustrating the method of
controlling traveling of the robot cleaner in accordance with the
embodiment, FIG. 7 is a schematic view illustrating rotating
directions of the driving wheels and the brush unit when the robot
cleaner in accordance with the embodiment travels forward, and FIG.
8 is a schematic view illustrating rotating directions of the
driving wheels and the brush unit when the robot cleaner in
accordance with the embodiment travels backward.
[0052] In FIG. 6, when the robot cleaner 1 is operated, the control
unit 110 judges whether or not cleaning is started (operation 200).
When it is judged that cleaning is started, the control unit 110
transmits driving instructions to the driving motors 120
respectively installed at the driving wheels 21 and 22 to rotate
the driving wheels 21 and 22 in the forward or backward direction
(a regular or reverse direction), thereby allowing the robot
cleaner 1 to travel on the floor while moving forward or backward
or rotating (operation 202).
[0053] During traveling of the robot cleaner 1, the control unit
110 rotates the brush unit 31 to perform a cleaning operation.
Here, in order to more smoothly carry out forward or backward
traveling of the robot cleaner 1 according to the rotation of the
brush unit 31, the driving sensors 102 detect a rotating direction
of the driving wheels 21 and 22, and transmit the detected rotating
direction of the driving wheels 21 and 22 to the control unit 110
(operation 204).
[0054] Thereafter, the control unit 110 determines a rotating
direction of the brush unit 31 according to the rotating direction
(the forward or backward direction) of the driving wheels 21 and
22, detected by the driving sensors 102 (operation 206).
[0055] For example, when the driving wheels 21 and 22 are rotated
in the forward direction (the regular direction) to cause the robot
cleaner 1 to travel forward, the control unit 110 determines the
rotating direction of the brush unit 31 to be a direction to
smoothly carry out the forward movement of the robot cleaner, i.e.,
the forward direction (the regular direction). When the driving
wheels 21 and 22 are rotated in the backward direction to cause the
robot cleaner 1 to travel backward, the control unit 110 determines
the rotating direction of the brush unit 31 to be a direction to
smoothly carry out the backward movement of the robot cleaner,
i.e., the backward direction (the reverse direction). Thereafter,
the control unit 110 transmits driving instructions to the brush
motor 32.
[0056] Therefore, when the driving wheels 21 and 22 are rotated in
the forward direction (the regular direction) of the robot cleaner
1, the brush motor 32 receives the driving instructions from the
control unit 110 and is rotated in the forward direction (the
regular direction) in the same way as the driving wheels 21 and 22,
as shown in FIG. 7. When the driving wheels 21 and 22 are rotated
in the backward direction (the reverse direction) of the robot
cleaner 1, the brush motor 32 receives the driving instructions
from the control unit 110 and is rotated in the backward direction
(the reverse direction) in the same way as the driving wheels 21
and 22, as shown in FIG. 8. Thereby, the robot cleaner 1 performs a
cleaning operation to suck foreign substances from the floor
(operation 208).
[0057] As described above, when the rotating direction of the
driving wheels 21 and 22 is changed into the regular or reverse
direction to carry out the forward or backward movement of the
robot cleaner 1, the brush unit 31 also receives the driving
instructions from the control unit 110 and changes its rotating
direction into the regular or reverse direction substantially
simultaneously with the change of the rotating direction of the
driving wheels 21 and 22, thereby causing the robot cleaner 1 to
smoothly carry out the forward or backward movement. Particularly,
the traveling performance of the robot cleaner 1 on a floor having
a high resistance, such as a carpet, may be improved.
[0058] Thereafter, the control unit 110 determines whether or not
cleaning is completed (operation 210), and when it is judged that
cleaning is not completed, the process is fed back to operation 204
and then subsequent operations are repeated.
[0059] As a result of the determination of operation 210, when it
is judged that cleaning is completed, the control unit 110 stops
driving of the driving motors 120 and the brush motor 32, and thus
stops the cleaning operation (operation 212).
[0060] FIG. 5 illustrates that the control unit 110 simultaneously
transmits driving instructions to the driving motors 120 and the
brush motor 32 and thus substantially simultaneously changes the
rotating direction of the driving wheels 21 and 22 and the rotating
direction of the brush unit 31. However, a case, in which the
control unit 110 transmits driving instructions only to the driving
motors 120 and thus changes the rotating direction of the driving
wheels 21 and 22 such that the driving wheels 21 and 22 and the
brush unit 31 are rotated in opposite directions, will be described
below. Since the rotating direction of the brush unit 31 on a hard
floor, such as a wooden floor or an oilpaper floor, does not
matter, the change of the rotating direction of the brush unit 31
only on a floor having a high traveling resistance, such as a
carpet, according to the rotating direction of the driving wheels
21 and 22 will be described. Here, the rotating direction of the
brush unit 31 may be changed using data sensed by the sensing unit
110.
[0061] In one example, a case using the driving sensors 102 will be
described. When the robot cleaner 1 moves backward so that that the
driving wheels 21 and 22 and the brush unit 31 are rotated in
opposite directions, and then meets a floor having a high traveling
resistance or an obstacle, the driving wheels 21 and 22 may not be
rotated due to the traveling resistance in spite of the driving
instructions from the control unit 110. In this case, the driving
sensors 102 sense movement of the driving wheels 21 and 22, and
when the driving sensors 102 do sense no movement, the driving
sensors 102 transmit the sensed result to the control unit 110.
Then, the control unit 110 transmits driving instructions to the
brush motor 32, and thus controls the brush unit 31 to be rotated
in the same direction as the rotation of the driving motors
120.
[0062] In a further example, a case of using the floor surface
sensor 104 will be described. When the robot cleaner 1 moves
backward so that the driving wheels 21 and 22 and the brush unit 31
are rotated in opposite directions, and then meets a floor having a
high traveling resistance, the floor surface sensor 104 senses that
the floor has a high traveling resistance, and transmits the sensed
result to the control unit 110. Then, the control unit 110
transmits driving instructions to the brush motor 32, and thus
controls the brush unit 31 to be rotated in the same direction as
the rotation of the driving motors 120.
[0063] In another example, a case using the load sensor 106 will be
described. When the robot cleaner 1 moves backward so that the
driving wheels 21 and 22 and the brush unit 31 are rotated in
opposite directions, and then meets a floor having a high traveling
resistance, a relatively large load is applied to the driving
motors 102. When the load is greater than a designated reference
value, the load sensor 106 senses that the load is greater than the
designated reference value, and transmits the sensed result to the
control unit 110. Then, the control unit 110 transmits driving
instructions to the brush motor 32, and thus controls the brush
unit 31 to be rotated in the same direction as the rotation of the
driving motors 120.
[0064] Further, the control unit 110 transmits a relatively large
torque to the brush motor 32 in an initial stage, when the rotating
direction of the brush unit 31 starts to be changed, and transmits
a relatively small torque to the brush motor 32, when change of the
rotating direction of the brush unit 31 has been carried out.
Thereby, during backward traveling of the robot cleaner 1, the
rotating speed of the brush motor 32 is increased in the initial
stage so as to withstand traveling resistance, and then is reduced
when the backward traveling of the robot cleaner 1 starts to be
carried out, thus exhibiting energy saving and noise reducing
effects.
[0065] As is apparent from the above description, a robot cleaner
in accordance with one embodiment allows driving wheels, which move
the robot cleaner, and a brush unit, which sweeps dust on a floor,
to be rotated in the same direction, and thus smoothly travels
forward and backward even on a floor having a high traveling
resistance, such as a carpet, thereby having an improved traveling
performance.
[0066] Although a few embodiments have been shown and described, it
would be appreciated by those skilled in the art that changes may
be made in these embodiments without departing from the principles
and spirit thereof, the scope of which is defined in the claims and
their equivalents.
* * * * *