External recharging device robot cleaner

SWEDEN (12) PATENT (13) C2 (ii) 523 910

<img file="SE523910C2_D0001.tif" />

2004-06-01

2002-10-19

2002-04-16

2002-04-16 (19) SE (si)

International class ⁷

A47L 9/00, 11/40

PATENT AND REGISTRATION (45) (41) (22) (24) (62) (86) (86) (83)

Patent filed Application widely available The patent application was submitted on expiration date

Tribunal application number International filing date Filing date for European patent application Deposit of microorganism (21) Patent application number 0201127-8

Application received as:

(XI Swedish patent application completed international patent application with number □ converted European patent application with number (30)

2001-04-18 KR 01/0020753 2001-08-06 KR 01/0047287

2001-08-06 KR 01/0047288 (73) (72) (74) (54) (56) (57)

PATENTS Samsung Gwangju Electronics Co. Ltd, 271 Oseon-dong Kwangsangu Gwangju City KR

INVENTOR Jeong-gon Song, Gwangju City KR, Jang-youn Ko, Gwangju City KR, Kwang-su Kim, Gwangju City KR

OMBUD Awapatent i Linköping AB

NAME Cleaning robot, cleaning robot system and method for a cleaning robot for return to an external charging device

CALLED PUBLICATIONS:

EP A2 0 363 339 (G05D 1/02), US A 5 155 684 (364 / 424.02)

SUMMARY:

A cleaning robot (10) capable of returning to an external charging device. The cleaning robot comprises a driving member (15) for driving a plurality of wheels (15a, 15b, 15c, 15d), at least one camera (13,14) installed on the body of the cleaning robot, which camera is arranged to photograph external environments, and a control unit ( 18) for photographing an image through a camera (13,14) for recognizing a connection position where the external charging device (30) is connected to the cleaning robot (10) and storing the photographed image; and to control the driving member (15) so that the cleaning robot (10) can be moved from the external charging device (30) to a destination when a work start signal is received in the cleaning robot (30) connected to the external charging device (30), and to track a path to the connection position of the external charging device (30) and the cleaning robot (10) during the return of a cleaning robot to the external charging device, comparing a current image taken by the camera (13,14) with a stored image of the connection position of the cleaning robot (10) and the external charging device (30). The return of the robot is performed when the cleaning robot (10) separated from the external charging device (30) completes its work or needs recharging, using the previously stored image and the current image taken by the camera. Thus, an error in the positioning process is caused by external interference signals, and errors in tracing a path and connection to the external charging device (30) can also be reduced.

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The numbers in brackets indicate international identification code, INID code. Letters in clamps indicate international document code.

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SUMMARY

A cleaning robot (10) capable of returning to an external charging device. The cleaning robot comprises a driving part (15) for driving a plurality of wheels (15a, 15b, 15c,

15d), at least one camera (13,14) installed on the body of the cleaning robot, which camera is arranged to photograph external environments, and a controller (18) for photographing an image through a camera (13, 14) for recognizing a connection position where the external charging device (30) is connected to the cleaning robot (10) and storage of the photographed image; and to control the driving member (15) so that the cleaning robot (10) can be moved from the external charging device (30) to a destination when a work start signal is received in the cleaning robot (30) connected to the external charging device (30), and to trace a path to the connection position of the external charging device (30) and the cleaning robot (10) during the return of a cleaning robot to the external charging device, comparing an actual image taken by the camera (13, 14) with a stored image of the connection position of the cleaning robot (10) and the external charging device (30). The return of the robot is performed when the cleaning robot (10) separated from the external charging device (30) completes its work or needs recharging, using the previously stored image and the current image taken by the camera. Thus, an error in the positioning process is caused by external interference signals, and errors in tracing a path and connection to the external charging device (30) can also be reduced.

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BACKGROUND OF THE INVENTION

1st technology Area

The present invention relates to a cleaning robot, a system using the same and a method for reconnecting to an external charging device and, more specifically, to a cleaning robot, a system, and a method for efficient reconnection to an external charging device.

2nd Description of prior art

Normally, a cleaning robot sucks dust or foreign matter from a cleaning surface and thus performs a cleaning operation while it is automatically traveling on a cleaning area without the influence of a user.

Since the cleaning robot regularly checks the location and measures distances to obstacles such as furniture, office appliances and wall, the cleaning robot can clean the cleaning area under control not to collide with any of the obstacles.

Such a cleaning robot is equipped with a battery, which supplies electricity necessary for the operation of the cleaning robot. The battery is rechargeable with an external charging device.

Accordingly, when the battery needs recharging, the cleaning robot must automatically locate the external charging device to return to the external charging device for charging.

For this purpose, the cleaning robot usually uses a high frequency signal received from the external charging device to detect the location of the external charging device.

However, this way has some shortcomings in that the level of the high frequency signal can be varied by external factors such as reflective waves and interference waves, and with level variation of the high frequency signal, the cleaning robot could not find the exact location necessary to dock with the external charging device.

SUMMARY OF THE INVENTION

The present invention has been made to overcome the aforementioned problems or deficiencies in the prior art, and consequently, it is an object of the present invention to provide a cleaning robot, a system using the same and a method for reconnecting to an external charging device.

Another object of the present invention is to provide an external charging device for easy access and reconnection of the cleaning robot to the external charging device.

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The invention is defined by the appended independent claims. Embodiments are apparent from the dependent claims and from the following description and drawings.

The above object is accomplished with a cleaning robot for performing a work, which cleaning robot comprises: a driving part for driving a plurality of wheels; at least one camera installed on the cleaning robot's body, the camera for photographing outside environments; and a controller for photographing an image through a camera and storing the photographed image. The cleaning robot is distinguished by the fact that it communicates wirelessly with an external charging device; the controller utilizes the photographed image to recognize a connection position where the external charging device is connected to the cleaning robot; the control unit for controlling the driving portion so that the cleaning robot can be moved from the external charging device to a destination when a work start signal is received in the cleaning robot connected to the external charging device; the control unit for tracing a path to the connection position of the external charging device and the cleaning robot during the return of a cleaning robot to the external charging device, comparing a current image taken by the camera with a stored image of the connection position of the cleaning robot and the external charging device.

The camera includes an upper camera mounted on the cleaning robot's body to photograph an object vertically above the cleaning robot for a direction of travel. The controller receives an image above the external charging device from the upper camera of the cleaning robot connected to the external charging device, to photograph the image and store the received image as the image of the connection location, and trace a path to the external charging device when the cleaning robot recovers the charging device by comparing the image taken by the top camera with the stored image of the connection location.

Preferably, the cleaning robot comprises an energy level detecting member for sensing the energy level of a battery mounted on the body in a removable manner with respect to the external charging device. The controller interrupts the work when it receives a recharge request signal from the energy level sensing portion, and controls the driving portion so that the cleaning robot can return to the external recharge device.

The cleaning robot further comprises a front camera mounted on the body of the cleaning robot to photograph an image in front of the cleaning robot in the direction of travel, and the controller receives the front image in front of the external charging device taken by the front camera and stores the received image as an image of the connection location of the cleaning robot, and traces a path to the external charging device by comparing the image taken by the camera with the stored image of the connection location of the cleaning robot and with the external

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Ί recharging device when the cleaning robot returns to the external recharging device.

The above objects are also accomplished with a cleaning robot system, including a remote control wireless communicating with a cleaning robot, the cleaning robot having a driving portion made up of a number of wheels and at least one camera mounted on a body of the cleaning robot for photographing external environments, the remote control for receiving an image from the camera for recognizing a connection position for the cleaning robot and an external charging device and storing the received image, the remote control for controlling the driving part so that the cleaning robot can move to a destination from the external charging device when a work start signal is received in the cleaning robot connected to the external charging device, the remote control for controlling the cleaning robot so that the cleaning robot can connect to the external charging device by comparing a current image taken by the camera with a stored image of the connection position of the cleaning robot and the external charging device.

Preferably, the remote control from the upper camera receives the image above the external charging device taken when the cleaning robot is connected to the external charging device, and stores the received image as the image of the connection point for charging.

It is also preferred that the remote control stops the cleaning robot upon receiving a recharge request signal generated by the energy level sensing portion and transmitted from the cleaning robot, and controls the driving portion so that the cleaning robot can return to the external recharging device.

Further, the above objects are also accomplished by a method of a cleaning robot for returning to an external charging device. The method comprises the steps a) when a work start signal is received to the cleaning robot connected to the external charging device, photography by a camera on the cleaning robot of an image for recognizing the charging position, for the cleaning robot's recognition of a position where the cleaning robot is connected to the external charging device; b) performing an assigned job by operating the cleaning robot; and c) when the cleaning robot needs a recharge, or when an assigned work is completed, trace a path to the external charging device by comparing a recent image recently taken by the camera with the stored image for recognition of the charging position, and returning the cleaning robot to the external charging device. .

BRIEF DESCRIPTION OF THE DRAWINGS

The aforementioned objects and features of the present invention will become more apparent by describing the preferred embodiment of the present invention with reference to the accompanying drawings, in which:

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FIG. 1 is a perspective view showing a cleaning robot in accordance with the present invention from which a housing has been removed;

FIG. 2 is a block diagram showing a cleaning robot system in which the cleaning robot of FIG. 1 is used.

FIG. 3 is a block diagram of a central controller of FIG. 2;

FIG. 4 is a perspective view showing an example in which an external charging device charges the cleaning robot of FIG. 1;

FIG. 5 is a perspective view showing an external charging device in accordance with the second preferred embodiment of the present invention;

FIG. 6 is a perspective view of an external charging device in accordance with the third preferred embodiment of the present invention; and

FIG. 7 is a flow chart for explaining a process in which the cleaning robot returns to the external charging device in accordance with the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

From now on, the present invention will be described in greater detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a cleaning robot in accordance with the present invention from which a housing has been removed, and FIG. 2 is a block diagram showing the cleaning robot system at which the cleaning robot of FIG. 1 is used.

Referring to the drawings, the cleaning robot 10 includes a vacuum-sucking part 11, a sensor part 12, a front camera 13, an upper camera 14, a driving part 15, a transmission part 17, a control part 18 and a battery 19.

The dust collecting part 11 is formed on a body 10a of the cleaning robot so that dust is drawn in from an opposite area of ​​the floor with the air suction process. The vacuum-sucking part 11 can be constructed in generally known ways. For example, the dust collecting part 11 may have a suction motor (not shown) and a dust chamber which collects the dust sucked through a suction pipe opposite formed with respect to the floor by driving the suction motor.

The sensor portion 12 includes obstacle sensors 12a located on the body surface at predetermined intervals from each other to send and receive signals, and a distance sensor 12b measuring a traveled distance.

Each obstacle sensor 12a includes a light red light emitting element 12a that emits an infrared beam of light, and a plurality of light receiving elements receiving reflected rays. The many light receiving elements are arranged along an outer periphery of the obstacle sensor 12a in a vertical pattern. Alternatively, the obstacle sensor 12a may be formed by an ultrasonic sensor which emits ultrasonic waves and receives the reflected waves. Obstacle sensor 12a can be used to measure the distance to the wall.

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The distance sensor 12b can be formed by a rotation detecting sensor which detects the number of turns for the wheels 15a to 15d. For example, the rotation detecting sensor may be an encoder that detects the number of turns for the motors 15e and 15f.

The front camera 13 is installed on the body 10a to photograph objects forward and output the photographed image to the control member 18.

Alternatively, a panning or tilting camera can also be used to photograph objects forward and above.

The driving member 15 includes a pair of front wheels 15a and 15b installed on the two front sides, a pair of rear wheel pairs 15c and 15d installed on the two rear sides, a pair of motors 15e and 15f rotating the rear wheels 15c and 15d, and a gear belt 15g which transmits the driving force generated from the rear wheels 15c and 15d to the front wheels 15a and 15b. According to the control signal from the controlling part 18, the driving part 15 drives a motor 15e in a certain direction and the other motor 15f in the opposite direction. Rotation in the opposite directions can be achieved by driving the motors 15e and 15f at different speeds (RPM).

Alternatively, that is, instead of the wheels, the driving member 15 can be constructed as a belt or caterpillar type.

The transmitting portion 17 transmits data to an antenna 17a, receives signals from the antenna 17a and transmits the received signal to the controlling portion 18.

The battery 19 is installed on the body 10a so that it can be charged by an external charging device 30 through a battery charging connection or terminal (not shown). The battery charging terminal is installed on the outer surface of the body 10a in such a way that the battery charging terminal is connected to and separated from the external charging device 30.

A battery charge level sensing portion 20 detects the charge level in the battery 19, and emits a signal for the charge request when detecting a result indicating the lower charge level.

The external charging device 30 is designed to supply electricity through a power line connectable to a conventional AC power source and then supply the delivered electricity to the cleaning robot 10 through the power supply terminals.

FIG. 4 shows an example of the external charging device 30.

As shown in FIG. 4, the external charging device 30 has a seat portion 33 formed on the body thereof. The cleaning robot 10 is located on the seat portion 33.

The seat portion 33 has an open forward portion through which the cleaning robot runs in and out. Also, grooves 34 are formed in the seat portion 33 to partially receive the wheels of the cleaning robot 10. The grooves 34 correspond to the placement of the wheels 15 on the cleaning robot with a normal seat location.

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The power supply terminals are formed in a rear wall of the seat portion 33 so that when the cleaning robot 10 is placed in a normal position, the power supply terminals are connected to the charging terminal of the battery 19 in the cleaning robot 10.

The power supply terminal 31 is connected to the power line 35 through an internal voltage transformer and power cable. The internal voltage transformer, can be omitted.

FIG. 5 shows another example of the external charging device 30 designed for easier location of that charging location and easier delivery to the external charging device 30. Here, the elements are designed with the same reference number as the previous drawings.

Referring to FIG. 5, the external charging device 30 includes an upper guide portion 36, spaced from the seat portion 33 by a predetermined distance in a parallel relationship thereto.

Further, guide walls 32 extend forwardly from the side walls of seat portion 33 such that guide walls 32 slope outward, gradually increasing the aperture width to allow easier advance of cleaning robot 10 into seat portion 33.

Supported by and spaced upwardly from the seat portion 33 by a predetermined distance parallel to the seat portion 33, the guide portion 36 is in the form of the letter 'L'.

To enable the top camera 14 of the cleaning robot 10 to photograph from the guide walls 32 to the seat portion 33, the horizontal portion of the guide portion 36 extends parallel to the seat portion 33 from a position corresponding to the seat portion 33 to a position corresponding to the guide walls 32.

An upper charge position control mark is formed on the bottom surface of the guide portion 36 in a linear fashion for easy recognition during the photography of the upper camera 14. The upper charge position control mark helps guide the cleaning robot 10 during its advance into the seat portion 33. The upper control mark is colored indistinguishable from the rest of the base of the control portion 36, so that the upper control mark 37 can be distinguished from the other parts during image processing. For example, the control mark 37 can be colored black, while the rest of the area is colored white.

FIG. 6 is a perspective view showing an external charging device in accordance with the third preferred embodiment of the present invention. Here, like elements are designated by the same reference number as in previous figures.

Referring to FIG. 6, the external charging device 30 includes a vertical guide portion 38 vertically formed on one side of the seat portion 33.

The vertical guide portion 38 projects from the seat portion 33 to a predetermined height where the vertical guide portion 38 faces the front camera 13 of the cleaning robot 10 as located on the seat portion 33.

The vertical control portion 38 is at a height higher than the front camera 13 of the cleaning robot 10 located on the seat portion 33.

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For easier recognition of the image during shooting with the camera camera 13 and also for easier determination of the cleaning robot 10's relation to the charge position, a circular charge position control mark 39 is formed near the center of the vertical control portion 38.

The charge position control mark 39 and the rest of the vertical control part 38 are differently colored.

The controller 18 processes the signal received through the transmitting portion 17 and controls the respective elements. If there is a key input device (not shown) on the body 10a with a plurality of keys to set various functions for the respective devices, the controlling portion 18 processes key signals input through the key input device.

When the cleaning robot 10 is out of operation, the control member 18 controls the respective elements so that the cleaning robot 10 can be in standby mode while it is connected to and charged by the external charging device 30. By connecting the cleaning robot 10 to the external charging device 30 when not working, the battery 19 maintains a certain charge level.

When a work start signal is received, the control portion 18 is connected to the external charging device 30, storing in the memory device 16 the images of objects above the external charging device 30 photographed with the upper camera 14 and / or images of objects in front of the external charging device 30 photographed with the front camera. 13th

That is, when the external charging device of FIG. 4 or FIG. 5 is used, the control portion 18 stores the images of equipment or ornaments above, or the images of the upper charge position mark 37, all taken with camera 14.

Using the external charging device of FIG. 6, the controlling portion 18 of the memory device 16 stores the images of the circular charge position control mark 39 taken by the front camera 13 facing the charge position control mark 39 when the cleaning robot 10 is connected to the external charging device 30 and / or when the cleaning robot 10 has withdrawn from the external charging device 30. with a predetermined distance.

The work start signal is for cleaning work or monitoring work with the cameras 12 and 14.

When the cleaning robot 10 returns to the external charging device 30, the control portion 18 compares the current images taken with the upper camera 14 and / or the front camera 13 with the stored images of the charge position for determining the charge position, and consequently controls the driving part 15 so that the cleaning robot 10 can dock with the external charging device 30.

That is, when the cleaning robot 10 returns to the external charging device 30, the controlling member 18 recognizes the distance and the direction of the cleaning robot 10 relative to the external charging device 30 by comparing the

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stored the images above and / or in front of the external charging device 30 with the newly taken image above and / or in front of the cleaning robot 10. Accordingly, the controlling member 18 controls the driving member 15 so that the cleaning robot 10 can return from the current position to the destination, e.g. the external charging device 30. When traveling on the path to the destination, the controlling portion 18 controls the driving portion 15 based on the information of the current position locked through the running distance measured by the encoder and by comparing the newly captured images above and / or images in front of stored images, so that the cleaning robot 10 can track the path to the destination.

In the examples described above, the controlling portion 18 directly photographs and stores the images above and / or in front of the external charging device 30, and the cleaning robot 10 returns to the external charging device 30 using the stored images and the current images.

According to another aspect of the present invention, to reduce the image processing load of the cleaning robot 10, a cleaning robot system is set up to externally handle processes for the return of the cleaning robot 10 such as storage / analysis of the images above and / or the images from the front.

Accordingly, the cleaning robot 10 is designed to wirelessly transmit images photographed with the cameras 13 and 14 and operate in accordance with control signals wirelessly received from outside. Also, a remote control 40 is provided for wirelessly controlling the cleaning robot 10 in processes such as operating control, return to the charging device 30, or the like.

The remote control 40 includes a wireless relay 41 and a central control unit 50.

The wireless relay 41 processes wireless signals received from the cleaning robot 10 and then transmits the processing signal to the central controller 50 through a line. Then, the wireless relay 41 wirelessly transmits the signal received from the central control unit 50 to the cleaning robot 41 through the antenna 42.

A normal computer can serve as the central controller 50, as shown in FIG. 3. As shown in FIG. 3, the central controller 50 includes a central unit (CPU, 51), a read-only memory (ROM, 52), a direct memory (RAM, 53), a display unit 54, an input unit 55, a memory 56 and a communication device 57.

The memory 56 has a cleaning robot control 56a which controls the cleaning robot 10 and also processes signals transmitted from the cleaning robot 10.

When enabled, the cleaning robot control 56a provides a menu on the display unit 54 for a user's settings of the control of the cleaning robot control. When a user makes a selection from the menu, the cleaning robot control 56a operates so that the cleaning robot 10 can perform the task selected by the user. Preferably, the menu is divided into large categories such as cleaning operations and control operations, and the large categories 5223 910 are provided with submenu menus which provide a variety of menus supported by the apparatus used such as target area menu, mode of operation, or the like.

When a work start signal is input to the cleaning robot 10 at a predetermined time by input device 55, from the cleaning robot 10, the control 56a receives and stores in memory 56 the images of the external charging device 30 taken with the upper camera 14 and / or images above and / or images in front of the external charging device 30 taken with the front camera 13 of the cleaning robot 10 during operation, connected to the external charging device 30. After that, the control 56a controls the cleaning robot 10 so that the cleaning robot 10 can perform an ordered task as ordered. According to control information received from the control 56a through the wireless relay 41, the control portion 18 of the cleaning robot 10 controls the driving portion 15 and / or vacuuming portion 11, and transmits the images above the cleaning robot 10 taken by camera 14 and / or the images in front of the cleaning robot 10 taken by front camera 13 to the central controller 50 through the wireless relay 41.

Upon receiving a battery charge request signal from the cleaning robot 10, or if the work is determined to be completed, the control 56a controls the cleaning robot 10 so that the cleaning robot 10 can return to the external charging device 30. During the control, the control 56a compares the images above and / or in front of the external charging device 30 stored in the memory 56 with the current image above and / or in front of the cleaning robot 10 taken with the upper camera 14 and / or the front camera 13 and transmits, tracks a path to the external charging device 30, and guiding the cleaning robot 10 back to the exact location of the external charging device 30.

The process of tracing a path to the external charging device 30 is described in more detail below with reference to FIG. 7th

In the description below, the initial state of the cleaning robot 10 is readiness, connected to the external charging device 30.

First, it is determined whether or not the work start signal has been received (step S100).

Upon determining that the work starting signal is received, the images are photographed by the charging location and stored for use when the cleaning robot 10 needs to recognize the position of the external charging device 30 (step S110).

Here are 'images of charge position' images above and / or in front of the external charging device 30 taken when the cleaning robot 10 is connected to the external charging device 30. When using the external charging device of FIG. 5 and 6, the images of the upper guide mark 37 or the circular guide mark 39 serve as pictures of the charging position.

When the shooting and storing of the images from the charging position is complete, the work ordered (step S120) is performed. That is, when the cleaning operation is ordered, the cleaning robot 10 is thus operated and separated separately from the connection to the external

523 910/0 charging device 30 and traveling on a predetermined path. During the movement of the cleaning robot 10, the vacuum cleaner part 11 of the cleaning robot 10, sucking in foreign matter, is driven from the cleaning surface. If recording work is ordered, the cleaning robot 10 is driven and separated from the connection to the external charging device 30 to a recording destination, photographs the target objects with the cameras 13 and 14, and transmits or stores the photographs.

Then, determine whether the work has been completed or not (step SI30).

When it is determined that the work is not completed in SI30, it is determined whether recharging is necessary or not (step S140).

When it is determined that the work has been completed, or recharging is needed, the return process is performed to the charging position.

Upon return, for example, a return path, the distance, and the direction of the external charging device 30 are calculated, using path information for the movement of the cleaning robot 10 which is measured since the separation of the cleaning robot 10 from the external charging device 30 and / or images around the cleaning robot 10 taken. of the cameras 13 and 14 and then stored the separation of the cleaning robot 10 from the external charging device 30. Then, in accordance with the calculated path information for the movement of the cleaning robot 10, controls the driving portion 15 for return to the external charging device 30.

During the separation and return of the cleaning robot 10 from / to the external charging device 30, it is preferable to determine the position using information obtained and recognized by comparing the travel distance measured by the encoder, current images taken with cameras 13 and 14 and stored images.

During the process where the cleaning robot 10 returns to the external charging device 30, it is determined whether or not the stored images from the charging device position are captured by the cameras 13 and 14 (step SI60). Specifically, it is determined whether the images taken by the top camera 14 or the front camera 13 include the images above the charging device or images of the charge position control marks 37 and 39, in whole or in part.

When it is determined that the current image does not contain the images of the charging position, the return path of the cleaning robot 10 is adjusted to the charging position (step SI70).

The return path adjustments include methods such as turning or forward movement of the cleaning robot 10 at a predetermined angle or distance.

Until the image of the charging position is included in the current image, the steps from SI50 to 170 are repeated.

When it is determined that the image of the charge position is included in the current image after the aforementioned process, the cleaning robot 10 is connected to the external charging device 30 (step SI80).

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it

The following are examples of using the external charging device 30 of FIG. 4 or FIG. 5.1. In this case, when the stored images above the external charging device 30 or the upper control mark 37 are captured and photographed by the upper camera 14 in S160, the cleaning robot 10 is advanced into the seat position 33 based on the image information from the images above the external charging device 30 or the upper the control mark 37. In particular, when a cleaning robot 10 almost reaches the external charging device 30 and thus some parts of the image above the external charging device 30 or the upper control mark 37 stored in the upper camera 14 are captured, the cleaning robot 10 advances into the seat part 33 of the external charging device 30 during adjusting its trajectory based on information about the positions of the control marks on a screen that is currently being photographed. Accordingly, the upper image or the upper guide mark 37 can detect a predetermined path on the screen.

The following are cases when the external charging device 30 of FIG. 6 is used. In this case, when the charge position control mark 37 is captured by the front camera 13 in SI60, the connection of the cleaning robot 10 to the external charging device 30 is based on the image information of the control mark 37 in S180 to be described below. That is, the photograph of the current charge position circular control mark 39 is compared with the stored image of the cleaning position control mark 39 in size, angle deviation and position on the screen, and the cleaning robot 10 returns to the charge position along a return path that matches the current image of the circular control mark 39 with the stored image of the circular guide mark 39 (step SI80).

When the image of the charge position is captured by camera 13, based on the position information on the screen of the recently loaded position image, the forward movement and positioning of the cleaning robot 10 into the seat portion 33 can be carried out with ease, and with the decrease of the frequency docking error.

As described above, with the cleaning robot 10, a system therewith and a method for finding a path to the external charging device 30 in accordance with the present invention, the cleaning robot 10, which was separated from the external charging device 30, can return to the external charging device 30 by using the previously stored images of the charging position and the images of the current position taken with the camera, when the cleaning robot 10 has completed its cleaning work or needs to be loaded. Accordingly, an error rate in recognition of the position, which often occurs due to external interfering signals, can be reduced, and also, errors in tracing a path to the charging device and connecting the cleaning robot 10 to the external charging device 30 can be reduced.

Thus far, the preferred embodiments of the present invention have been illustrated and described. However, the present invention is not limited to the preferred ones

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the embodiments described herein, and a person skilled in the art can modify the present invention without changing the idea of ​​the present invention according to the claims.

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