Mobile robot and its route correcting method

SWEDEN (12) PATENT (13) C2 (ii) 522 383 (51)

International class ¹

G05D 1/00, 1/02, A47L 9/00, G01S 17/93 (19) SE

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

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

Application number International filing date

Filing date for European patent application Deposit of microorganism (21) Patent application2004-02-03 ^number 0102950-3 2002-05-18

2001-09-05 Application received as:

2001-09-05 Swedish patent application completed international patent application - with number converted European patent application with number (30)

2000-11-17 KR 00/68445 2000-11-22 KR 00/69621

2000-11-17 KR 00/68446 (73) (72) (74) (54) (56)

Assignee

INVENTOR

AGENT

NAME

Samsung Kwangju Electronics Co., Ltd., 271 Oseon-dong Kwangsan gu Kwangju-city KR

Jeong-gon Song, Kwangju-city KR, Sang-yong Lee, Kwangjucity KR, Seung-bin Moon, Suwon-city KR, Kyoung-mu Lee,

Seoul KR

Awapatent i Linköping AB

Mobile robot and course adjustment procedure for the same with a position recognition device that senses base marker on the ceiling.

(57)

CALLED PUBLICATIONS:

JP A 9 106 457 (G06T 1/00), US A 5 040 116 (364 / 424.02)

B. Verma et al. Behavior Integration for Landmark Tracking and Real-Time Obstacle Avoidance. IEEE ICIPS '98, Proceedings of the second IEEE International Conference on Intelligent Processing Systems, 4-7 August 1998, pages 594-598 Gold Coast Australia.

MR Kabuka et.al. Position Verification of a Mobile Robot Using Standard Pattern. IEEE Journal of Robotics and Automation, vol. RA-3, No. December 6, 1987

SUMMARY:

A mobile robot (1), which can sense its reading and adjust its direction in response to an obstacle present in its trajectory. comprises a driving device (31 - 33). an obstacle detecting device (41 - 45) for detecting the presence of an obstacle, a position recognition device (2 in - 23), a control part (10) and a power source (60). The position recognition device comprises a first image camera (21) facing the ceiling of a room and a first image card (23). The first camera detects a base marker on the ceiling. The first image card processes an image from the first image camera and sends image data to the control portion (10). The obstacle detecting device comprises a linear laser (41) for delivering a linear beam of light to the obstacle, a second imaging camera (43) for detecting a reflected linear beam of light from the obstacle, and a second image card (45)._? to process the image data captured by the other image camera. 45,

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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 mobile robot (1) capable of detecting its position and adjusting its direction in response to an obstacle present in its path comprises a driving device (31 - 33), an obstacle detecting device (41 - 45) for detecting the presence of a obstacles, a position recognition device (21 - 23), a control part (10) and a power source (60). The position recognition device comprises a first image camera (21) facing the ceiling of a room and a first image card (23). The first camera detects a base marker on the ceiling. The first image card processes an image from the first image camera and sends image data to the control portion (10). The obstacle detecting device comprises a linear laser (41) for emitting a linear beam of light toward the obstacle, a second imaging camera (43) for sensing a reflected linear beam of light from the obstacle, and a second image card (45) for processing the image data captured by the second one. photo camera.

(Fig. 2)

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Technical area

The present invention relates to a robot that automatically moves in a room and more specifically to a mobile robot which has an imaging camera to detect its location and to avoid collision with obstacles in the room. The present invention also relates to an adjustment procedure for the course of the mobile robot.

Description of the Related Art

In general, a mobile robot has a power source and a sensor mounted in its body and can thus automatically move around a given area without any external power supply or manipulation. There are two main types of mobile robots that are used indoors: Robots for room cleaning in the house and robots that guard the house against any intruders.

The conventional mobile robot uses a random motion method, with which the mobile robot moves in a random direction without observing its position, repeatedly changing its direction whenever it encounters an obstacle such as a wall, table, etc.

Such a conventional mobile robot includes a driving device for driving the mobile robot around a room, an obstacle detecting device for detecting the presence of an obstacle, such as a wall, a table, etc., a control member for adjusting an orientation of the mobile robot by controlling the driving device and the obstacle detecting device as well as a power source for storing and supplying current to respective devices.

The driving device may be a wheel type device utilizing a servo motor or a stepper motor to drive a plurality of wheels and move the robot, a trolley type device utilizing an endless belt, or a combination type device utilizing a plurality of legs. Among these types of devices, the wheel type driving device is the most widely used.

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The obstacle detecting device detects obstacles, such as a wall, table, etc., with an ultrasonic or laser sensor and transmits a corresponding signal to the control member. The sensor of the obstacle detecting device is preferably mounted on the front of the mobile robot parallel to a driving surface, to more accurately detect the obstacle located in the driving path.

The control portion includes a microprocessor and a memory mounted thereon for controlling general operations of the mobile robot, such as transmitting a start command to the driving device, controlling the movement of the driving device to avoid an obstacle in accordance with the signals received from the obstacle detecting device, and an internal , pre-installed program and for charging the power source with electricity when it determines that the power level is below a predetermined value.

The power source supplies power for driving various parts of the mobile robot, such as the motor, which rotates the wheels of the driving device, the sensor that detects the presence of obstacles and the control part, etc. The power source is usually a battery that allows the mobile robot to operate for a predetermined period of time without connection to any external power source.

The operation of the mobile robot, constructed in the manner described above, will be described in detail below.

First, when the mobile robot receives a start command, the control portion transmits a driving order and corresponding sensing signal to the driving device and the obstacle detecting device, respectively. In response to the signal from the control part, the driving device drives in a certain direction by driving the motor. At this time, through the function of the sensor, the obstacle detecting device sends a sensing signal to the control part. During operation of the mobile robot, when the sensor senses the presence of an obstacle within a predetermined distance from the robot, the control portion to send a command to the driving device will change the driving direction of the mobile robot. Whenever the mobile robot encounters an obstacle, the driving direction of the mobile robot changes

522 383 through the processes described above. That is, the mobile robot runs in accordance with its initial position and the obstacle positions, and draws a random track as shown in Figure 1.

A mobile robot with such a random movement is found to be ineffective when moving within a limited range, as it moves along a random path. Another disadvantage of the mobile robot's random movement is that it repeatedly moves over the same area.

The ultrasonic sensor of the conventional obstacle detection device includes an ultrasonic transmitting portion for transmitting ultrasonic waves, and an ultrasonic receiving portion for receiving reflected ultrasonic waves from the obstacle. By measuring a time gap between the ultrasonic transmission and the reception of reflected ultrasound, the controlling part calculates a distance from the mobile robot to the obstacle and accordingly controls the motor of the mobile robot to avoid the obstacle.

Although the conventional obstacle detecting device and its method can measure the distance from the mobile robot to the obstacle, it cannot adequately handle the obstacle with regard to the obstacle status as it is impossible to obtain accurate information on the obstacle status, such as the obstacle shape or similar. Consequently, it is impossible for the mobile robot to decide whether to pass or weigh the obstacle.

It is required by the mobile robot to maintain a predetermined orientation to perform a cleaning or guard operation more efficiently. For this, it is necessary to periodically check if the mobile robot is running along the correct course and to correct the orientation of the mobile robot if it is determined that the mobile robot has deviated from the course.

To ensure that the mobile robot runs along the correct course, the mobile robot uses a control tape on a wall in a room as a reference.

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When the control tape is attached to the floor, the mobile robot's control of the control tape is done using a photo sensor or a magnetic sensor. The mobile robot runs along the control tape. The relative position of the control tape with respect to the sensor determines whether the mobile robot is on the right course or not.

When the room wall is used as a reference, it is determined whether the mobile robot is running along the right course or not according to the distance of the mobile robot from the wall, as detected by a sensor, such as an ultrasonic sensor, etc. Depending on the distance between the mobile robot and the wall, the mobile robot will adjust its orientation.

Although these ways of adjusting the mobile robot's course, ie. the use of a control tape or wall as a reference can be useful for controlling the mobile robot's running, they are hardly applicable to a mobile robot that detects its position using an imaging camera. That is, separately arranging the control tape or ultrasonic sensor on the mobile robot, which senses its position by means of an imaging camera precisely to determine whether or not to adjust the orientation of the mobile robot, causes disadvantages such as complicating manufacturing processes and raising manufacturing costs.

The invention in brief

The present invention has been accomplished to overcome the aforementioned problems of the prior art. Accordingly, the object of the present invention is to provide a mobile robot that can effectively run along a certain course during sensing of its location and with the avoidance of repeated passages over the same area.

Another object of the present invention is to provide a mobile robot capable of determining whether to pass or weigh an obstacle in its direction of travel, based on information on the shape of the obstacle. Information on the shape of the obstacle

522 383 is provided by an obstacle detecting device having a line laser and an imaging camera.

Yet another object of the present invention is to provide a method for controlling the orientation of the mobile robot, which detects its location by using an imaging camera, in accordance with determining whether it should maintain or take another path.

The above stated objects are achieved in whole or in part by a mobile robot as well as a method for regulating a course or driving path for a mobile robot, according to the independent requirements attached.

Thus, the invention comprises a mobile robot comprising a driving device for moving the mobile robot around a room, an obstacle detecting device for detecting the presence of an obstacle, a control part coupled to and controlling the driving device and the obstacle detecting device. The mobile robot is distinguished by a position recognition device coupled to the control member to determine a current position of the mobile robot, which position recognition device comprises a first image camera and a first image card, the first image camera imaging the ceiling in a room and sensing a base marker in the ceiling and the first image card processes an image from the first image camera and sends data to the control part as well as a power source connected to the control part, said power source being arranged to store and supply electricity to said driving device, said obstacle detecting device, said position recognition device and said control member, said base marker being a recognition mark exhibiting a base disk and a plurality of points formed on said base disk at a predetermined distance from each other.

Furthermore, the invention comprises a method for controlling a course or driving path of a mobile robot, which mobile robot comprises a driving device for moving the mobile robot around in a room, an obstacle detecting device for detecting the presence of an obstacle, a position recognition device for determining a current position of the mobile robot, a control part for controlling the driving device, the obstacle detecting device and the position recognition device, and a

522 383 power source for storing and supplying electricity to each of the devices and control portion. The method comprises (I) photographing a base marker using a first image camera in the position recognition device, which generates image data of the base marker using a first image card, the base marker being a recognition mark exhibiting a base disk and a number of points formed on the base disk of a base disk. predetermined distance from one another; (II) determining whether the coordinates of the base marker obtained by the data processing of the control member; corresponds to the coordinates of the predetermined roadway, and (III) steering the driving section to move the mobile robot in a direction at a corresponding distance to compensate for any deviation from the predetermined roadway when the coordinates of the base marker do not match the coordinates of the predetermined roadway .

The mobile robot according to a preferred embodiment of the present invention comprises a vacuum cleaner, which has a suction opening for suction of contaminants, a dust collection part for collecting the pollution and a motor drive part for generating suction power.

Brief description of the drawings

The above and other objects and advantages of the present invention will be readily apparent upon reading the following detailed description given in conjunction with the accompanying drawings, in which: - Figure 1 is a view illustrating the path of movement of a conventional mobile robot; Fig. 2 is a perspective schematic view illustrating the structure of a mobile robot in accordance with a preferred embodiment of the present invention; 3 shows a block diagram illustrating the functions of respective parts of the mobile robot of the present invention;

522 Fig. 383 shows a flow diagram explaining a method for recognizing a mobile robot position according to the present invention; Fig. 5 is a view of an example of a basic mark for the mobile robot of the present invention; a view illustrating the path of movement of the mobile robot moving in accordance with a mask image set during a learning process; 7 shows a flowchart explaining a method for detecting an obstacle utilizing an obstacle detecting device in the mobile robot of the present invention; Fig. 8 is a view explaining a process for calculating a distance from the mobile robot to an obstacle; Fig. 9 shows a view briefly illustrating a process for forming a three-dimensional image with a plurality of linear images; 10 shows a flowchart explaining a method for adjusting the orientation of the mobile robot according to the present invention; Figs. 1 ΙΑ, 1B and 11C show views illustrating lines formed by base markings shown in a picture window of a first picture camera in accordance with the Fig. 12 shows a view of the mobile robot moving along a certain path as it senses its position.

Detailed description of the preferred embodiment

The preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

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Referring to FIG. 2 and 3, it appears that a mobile robot 1 comprises a driving device 30 for moving the mobile robot 1 along a flat surface, a position recognition device 20 for sensing a position for the mobile robot 1 using a first image camera (CCD camera) 21 , an obstacle detecting device 40 for detecting the presence of an obstacle in the path of the mobile robot 1, a remote controlled transmitter / receiver 50 for transmitting or receiving a start / stop command to / from the mobile robot 1 and a power source 60 for storing and supplying power to the respective components of the mobile robot 1.

The driving device 30 comprises a pair of wheels 33 which can move forward and backward, to the right and to the left, a motor 32 for driving the wheels 33 and a motor drive 31 to control the motor 32 in response to signals received by the motor drive 31 from the control part. 10th

The position recognition device 20 includes a first image camera 21 which is arranged vertically to image a ceiling on which a base marker 70 (Fig. 5) is mounted. The position recognition device 20 further comprises a first image card 23 for setting relevant thresholds with images photographed with the first image camera

21.

The obstacle detecting device 40 includes a linear laser 41 for transmitting a linear light beam in the path of the mobile robot 1's driving direction, a second imaging camera 43 for sensing a linear light beam reflected from an obstacle located in the path of the mobile robot 1, and a second image card. 45 for processing images photographed with the second imaging camera 43.

The linear laser 41 is often referred to as "linear transmitter" because it sends a beam in the form of a straight line to an image plane. The image plane is perpendicular to the optical axis of the linear laser 41. The linear laser 41 is mounted on a front surface of the mobile robot 1 and detects the presence of obstacles that may be in the path of the robot.

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The second imaging camera 43 is mounted above the linear laser 41 to intercept each linear beam from the linear laser 41 reflected from an obstacle. The second imaging camera 43 comprises a filter applied thereto to exclusively detect a reflected beam from the linear laser 41. The filter also allows an exclusive passage for a wavelength corresponding to the linear beam from the linear laser 41, so that the second imaging camera 43 senses exclusively the linear beam from the linear laser 41.

The second image board 45 is mounted on one side of the second imaging camera 43 and is connected via connecting wires to the control member 10 and the other imaging camera 43.

The remote transmitter / receiver 50 allows a user to remotely control the start and stop of the mobile robot. That is, the remote transmitter / receiver 50 receives a start or stop command from the user and sends a status signal for the mobile robot 1 to the user.

The power source 60 is an electric battery that stores and feeds a predetermined electrical voltage to the respective components of the mobile robot 1.

For total control of the mobile robot 1, the control part 10 is coupled to the motor drive 31 of the driving device 30, the position sensing device 20, the obstacle detecting device 40, the remote controlled transmitter / receiver 50 and the power source 60. The control part 10 comprises an image data processor 11 which has a microprocessor for calculating position data by means of image data transmitted from the first and second image cards 23 and 45. That is, the control part 10 uses its own local information and location and shape information for an obstacle to setting a target point and a driving course for the mobile robot 1. The control part 10 further directs the mobile robot 1 along the straight course towards the target point. The positioning information of the mobile robot is obtained by using image data for the base marker 70, which is obtained by photographing the roof on which the base cursor 70 is applied and by processing the photographed image with the first image card 23.

522 383 for and the shape of the obstacle is obtained using linear image data obtained by photographing the obstacle with the second imaging camera 43 of the obstacle detecting device 40 and processing the photographed image with the second image card 45.

The operation of the above-described mobile robot 1 will be described in more detail below.

The driving process and position recognition process for the mobile robot 1 via the first imaging camera 21 will be described with reference to Fig. 4.

First, the mobile robot 1 receives a start command, the control portion 10 initializes and controls a predetermined direction and a predetermined distance (steps S10 and SI1). When there is no data regarding the predetermined direction and the predetermined distance, the control member 10 requests image data from the position recognition device 20 (step SI2). Upon receiving the request for image data from the control part 10, the position recognition device 20 uses the first image camera 21 to photograph the roof from the current position of the mobile robot 1. Based on the image photographed by the first imaging camera 21, the relevant threshold is set and sent to the image data processor 11 of the control member 10 (step S13). Upon receiving image data from the first image card 23, the image data processor 11 detects the position and direction of the base marker 70 recognition points 71 and 73 (FIG. 5) by an area correlation and outputs a distance and a direction that the driving device 30 has to move (step S14). . The base marker 70, which is mounted on the ceiling, can be formed of a suitable material as long as it can be recognized by the first imaging camera 21. It is advantageous to use recognition markers for clearer recognition. An example of base marker 70 is shown in Fig. 5. Base marker 70 is a recognition mark comprising a disk 75, a larger reference point 71, and a smaller reference point 73. The larger reference point 71 is for determining the base position, while the smaller reference point 73 is for for controlling a direction of the mobile robot 1 based on its relation to the larger reference point 71.

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The control part 10 transmits data on the movement distance and the direction from the image data processor 11 to the driving device 30 and the driving device 30 operates in the direction and with the distance determined by the signal from the control part 10 (step SI5).

The process for searching the recognition points 71 and 73 through an area correlation of the image data threshold will be described in more detail below.

Area correlation is a process where the mask image data for the base cursor 70 is compared with the image data obtained from the image of the roof photographed from a certain distance and the invention of a position indicating a similar mask image on an image window obtained by the first image camera 21. As shown in Fig. 6 for example, an insert operation of the mask image 70 is performed in a downward orientation.

Further, the position having a mask image is similar to that of the mobile robot 1 as follows. First, area correlation coefficients for the mask image, which is a result of the submit operation, are obtained from the entire area of ​​image data for the image as it is photographed from a certain distance. Then, the region that has the greatest correlation coefficient is selected because it has the image most similar to the image of the recognition marks 73 and 75 on the base marker 70 to which the mobile robot 1 is directed. The position of the base cursor 70 is expressed through the image photographed with the first image camera 21 and formed on the image window (W) in pixel coordinates. Consequently, by using the original coordinates of the base cursor 70 and the coordinates of the base cursor 70 on the current image window (W), the current position and direction of the mobile robot are obtained. Since the position of the base cursor 70 is further obtained in pixel coordinates during each sampling period during which the photograph is taken. the first image camera 21, the motion and trajectory of the mobile robot 1 are also obtained.

The area correlation coefficient is expressed by

522 383 where r (d_xd_y) is an area correlation coefficient, fj is an input mask image, / j is an average of the input mask image, f₂ is an average of f2, (d_xd_y) is the required displacement distance for the mask image in coordinates, (x, y) is a coordinate and S is the original image.

Next, a method for detecting the presence of an obstacle while driving will be described with reference to Fig. 7.

The obstacle detection method comprises the steps of: aligning the linear laser 41 to emit a linear beam against an obstacle located in the path of the mobile robot (step 31); causing the second imaging camera 43 to sense the reflected linear beam from the obstacle (step S32); causing the second image card 45 to process the image from the second image camera 43 into image data computable using software (step S33); and calculating the distance from the mobile robot 1 to the obstacle using the image data (step S34).

In the light emitting step (S31), when the linear laser 41 directs a linear beam toward an obstacle, the shape of the obstacle distorts the beam. In the sensing step (S32), the second imaging camera 43 forms an image by sensing the reflected distorted beam from the filter. In the image data processing step (S33), the second image card 45 performs the thresholding process to simplify the image sensed in the sensing step (S32) and to use a thinning process to reduce the size of the image to be as small as possible. In the distance calculating step (S34), the distance from the mobile robot 1 to the obstacle is calculated based on the image data obtained from the image data processing step (S43). The mobile robot 1 repeats the above mentioned obstacle detection processes until it receives all information about the obstacle in its path.

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Accordingly, the distance from the mobile robot 1 to the obstacle can be easily obtained by trigonometry with a pair of values. As shown in Fig. 8, these values ​​are: An angle (θι ρ) between linear laser 41 and mobile robot 1, the distance (y_Lp) between the imaging camera 43 and the linear laser 41, the distance (f₀) between a lens 43a of the imaging camera 43 and an image plane 43b on which the image of the obstacle is formed, and the distance (y) from the image plane 43b to the center of the lens 43a. With these values, the distance (Z) from the mobile robot 1 to the obstacle is obtained by the trigonometric equation (refer to Fig. 8):

- = tan £_{/ r} Yu&gt; -YZ

Reformulate- = tan θ_ιρ by substituting Xo = y_Lp · tan 0_Lp and yu&gt; -yy = - (Z · yi) / f₀ and obtain _

L-OV / o tane +)

Since the angle (Ö_LP) between linear laser 41 and mobile robot 1, the distance (f₀) between the lens 43a of the imaging camera 43 and the obstacle image plane 43b and the value of Xo = y_Lp · tan 0_LP all are expressed in constants, the distance (Z) from the mobile robot 1 to the obstacle can be obtained only by obtaining a value (yi) corresponding to a horizontal distance from the lens 43a to the end of the image data for the image formed on the image plane.

By solving the above equations with the image data, the shape of the obstacle can be determined.

According to another preferred embodiment of the present invention, a three-dimensional image can also be obtained by using a plurality of linear lasers 41. A plurality of linear lasers 41 are arranged to deliver laser beams to the obstacle at an angle of incidence.

522 383 which is such that the angle of incidence of the linear beam against the obstacle can be sensed by the imaging camera 43. The plurality of linear lasers 41 emit the linear beams against the obstacle and the imaging camera 43 detects the reflected beams from the linear lasers 41. The image processing of the reflected beams then yields car5 the. Fig. 9 illustrates the processes for forming the three-dimensional image from a plurality of linear images. In this way, the mobile robot obtains more accurate data on the obstacle such as on the shape of the obstacle.

Finally, the process of reaching the target position while retaining the correct course will be described in more detail below.

When the mobile robot 1 receives the start command, the control portion 10 initializes and requests to receive image data from the position recognition device 20 and the obstacle detecting device 40. Upon receiving the image data request from the control member 10, the position recognition device 20 initializes the roof in which the base marker 70 is placed. and generates an image. Then, the first image card 23 processes the image into a threshold information and transmits the same to the control portion 10. The obstacle detecting device 40 uses its linear laser 41 and its second imaging camera 43 to generate image data about the obstacle located in the path of the mobile robot 1 and transmits the same to the control member 10.

Software in the control part 10 processes the image data received from the position recognition device 20 and the obstacle detecting device 40 for obtaining information about the obstacle and the current position of the mobile robot. The control part 10 in25 then sets the target position and the course towards the target position based on the information obtained above.

The control part 10 sends run command to the run part 30 for a specified path, periodically checks the coordinates of the base cursor 70 at predetermined intervals and determines whether the mobile robot 1 moves along the determined path or not. If the coordinates of the base cursor 70 deviate from the determined path, the control portion 10 controls

522 383 the driving device 30 to move the mobile robot 1 in the opposite direction, thus maintaining the correct path for the mobile robot 1. After several path adjustments and when the mobile robot 1 reaches the target position, the mobile robot 1 stops moving or continues to move. there is a subsequent order.

This method of the control part 10 for obtaining the current position of the mobile robot 1 is assumed to correspond to the position recognition process of the mobile robot 1 described above. Accordingly, the detailed description for this is omitted.

Here, the process of controlling the course and adjusting the direction of the mobile robot 1 when the mobile robot 1 deviates from its course will be described in more detail with reference to Figures 10, 1 ΙΑ, 1 IB and 11C.

The control portion 10 requests image data about the base cursor 70 from the position recognition device 20. Upon receipt of the request from the control portion 10, the position recognition device 20 photographs the roof in which the base marker 70 is applied and generates an image of the base marker 70. Then, the first image card 23 processes the image into image data. can be processed by software and transmits the image data to control part 10 (step S51).

The control part 10 calculates the coordinates of the base cursor 70 by the process of area correlation, which is identical to the process of obtaining the position of the mobile robot 1 using image data transmitted from the position recognition device 20 (step S52).

Then, the control part 10 compares the coordinates of the base marker 70 obtained from the current position of the mobile robot 1 with the coordinates of the course determined in the course determining step (S53).

When the current coordinates of the base cursor 70 do not match the coordinates of the specified course, the control portion 10 calculates the deviation in the direction and distance from the determined coordinates of the course. The control part 10 then controls

522 383 motor 32 of driving device 30 to move the mobile robot 1 so that the deviations are compensated by moving in the opposite direction to a deviating distance (step S54). For example, if the mobile robot 1 is off course to the right of the base marker 70, then the control member 10 directs the motor 32 to drive the driving device 30 to the left, ie. back to the track. Such processes are shown in Figures 11A, 1B and 11C. FIG. 11A shows the position of the base cursor 70 indicated on the picture window (W) of the first imaging camera 21 as the mobile robot 1 moves along a straight path. Similarly, Fig. 1B shows the position of the base cursor 70 on the image window (W) of the imaging camera 21 as the mobile robot 1 drives away from the straight path, while Fig. 11C shows the position of the base cursor 70 when the mobile robot 1 returns to the path of movement. The reference numerals 71 and 73 in Fig. 11A refer to both recognition points of the base marker 70.

Thereafter, the control part 10 determines if the current position is the target position (step S55). If not, the control member 10 requests that the location recognition device 20 provides image data for the base cursor 70 to determine if the mobile robot 1 is on the same coordinates as the coordinates of the determined course.

The control portion 10 periodically repeats the above-mentioned processes at predetermined intervals until the mobile robot 1 reaches the target position, so that the mobile robot 1 moves along the determined course.

Fig. 12 shows the movements of the mobile robot 1 which can sense its position and its operation around objects in a room. Such a mobile robot 1 can be used as a home appliance, ie. a vacuum cleaner mobile robot. Here, the mobile robot 1 further comprises a vacuum cleaner having a suction nozzle for sucking up contaminants, a dust collecting part for collecting the pollutants from the suction air, and a motor drive part for generating suction power. The trajectory or moving path of the vacuum-sucking mobile robot 1 may be pre-entered in different program patterns in accordance with the geography of the room.

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As described above, the mobile robot 1 according to the present invention can sense its current position and can also effectively move at a given course without repetitive passage of the same area.

Further, according to the present invention, the mobile robot 1, since the mobile robot 1 obtains information on the shape of the obstacle by utilizing the linear laser 41 and the second imaging camera 43, can decide whether to pass or avoid the obstacle in accordance with the status of the obstacle.

Furthermore, in that the mobile robot 1 according to the present invention senses its position by using the first imaging camera 21, it can determine whether or not to maintain the current moving path and adjust its orientation when determining any deviation from the desired course.

As stated above, a preferred embodiment of the present invention has been shown and described. Although a preferred embodiment of the present invention has been described, it is to be understood that the present invention is not limited to this preferred embodiment. Various changes and modifications may be made by one of ordinary skill in the art without departing from the spirit of the present invention as expressed in the appended claims.

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