SELF TRAVELING DEVICE AND METHOD AND SELF CARRYING DEVICE USING THE SAME

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a self-traveling device and method, and a self-carrying device using the same, and more particularly to a device and method for carrying baggage etc. while self-traveling along a traveling path by tracking the traveling path of a specific object.

Description of the Related Art

Customers of a large store use shopping carts to store and move purchased goods. Conventionally, a user of a shopping cart adjusts direction of the shopping cart and provides power to the cart. Accordingly, a user of the cart should search for desired goods while paying attention to the traveling direction of the cart, and should apply considerable force to move the cart when a large quantity of goods is contained in the cart.

Furthermore, while a user chooses goods, a cart may run into other users, etc. and thus may be move to unwanted places.

Meanwhile, while boarding or disembarking an aircraft in an airport, passengers use travel bags for carrying baggage. A direction of a conventional travel bag is adjusted by a user

and power thereof is provided by a user, like the conventional shopping cart. Therefore, the conventional travel bag has the same problem as the conventional shopping cart. In an airport, unlike a large store, there is high probability of personal baggage being lost. However, since the conventional travel bag is not equipped with an anti-theft means for preventing loss of baggage, passengers should always watch their travel bag.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a self-traveling device and method for self-traveling in front of an object along a traveling path of the object by sensing the traveling path of the object.

It is another object of the present invention to provide a device for carrying baggage while self-traveling in front of an object along a traveling path of the object by sensing the traveling path of the object. It is a further object of the present invention to provide a recording medium which records a program which can execute through the computer a self-traveling method for self- traveling in front of an object along a traveling path of the object by sensing the traveling path of the object. In accordance with an aspect of the present invention,

the above and other objects can be accomplished by the provision of a self-traveling device including a plurality of driving wheels, and motors for rotating the plurality of driving wheels. The self-traveling device includes: a distance measuring sensor for transmitting an object sensing signal to an object and receiving the object sensing signal reflected from the object to measure a distance between the object and the distance measuring sensor; a direction tracker for receiving a radio signal transmitted by a transmitter carried by the object and calculating direction information based on the received radio signal; a movement information calculator for calculating a predicted location in front of the moving direction of the object based on the measured distance, the direction information and previous movement information, and calculating movement information to move to the predicted location; and a controller for controlling driving of the motors based on the calculated movement information.

In accordance with another aspect of the present invention, there is provided a self-traveling method for controlling a plurality of driving wheels, and motors for rotating the plurality of driving wheels . The method includes : receiving a radio signal transmitted by a transmitter carried by an object; calculating direction information based on the received radio signal; transmitting an object sensing signal

to the object and receiving the object sensing signal reflected from the object to measure a distance from the object; calculating a predicted location in front of the moving direction of the object based on the measured distance, the direction information, previous movement information, and a running speed; calculating rotation information for rotating to face toward the predicted location, calculating individual running speeds of the motors based on the rotation information, and calculating the running speed based on a difference value between a distance from the self-traveling device to the predicated location and a previously set distance; controlling driving of the motors based on the individual running speeds of the motors; and controlling the driving of the motors based on the calculated running speed. In accordance with yet another aspect of the present invention, there is provided a self-traveling method for controlling a plurality of driving wheels, motors for rotating the plurality of driving wheels, and a direction converting means. The method includes: receiving a radio signal transmitted by a transmitter carried by an object; calculating direction information based on the received radio signal; transmitting an object sensing signal to the object and receiving the object sensing signal reflected from the object to measure a distance from the object; calculating a predicted location in front of the moving direction of the object based

on the measured distance, the direction information, previous movement information, and a running speed; calculating rotation information for rotating to face toward the predicted location, and calculating the running speed based on a difference value between a distance from the self-traveling device to the predicated location and a previously set distance; controlling the direction converting means based on the rotation information; and controlling the driving of the motors based on the calculated running speed. In accordance with still yet another aspect of the present invention, there is provided a self-carrying device including a plurality of driving wheels, and motors for rotating the plurality of driving wheels. The method includes: a distance measuring sensor for transmitting an object sensing signal to an object and receiving the object sensing signal reflected from the object to measure a distance from the object; a plurality of direction measuring sensors for receiving a radio signal transmitted by a transmitter carried by the object, the plurality of direction measuring sensors being installed at the rear, left and right sides of the self-carrying device at regular intervals; a movement information calculator for calculating a predicted location in front of the moving direction of the object based on the measured distance, direction information and previous movement information, and calculating movement information for moving

to the predicted location; and a controller for controlling driving of the motors based on the calculated movement information.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram of a self-traveling device according to an exemplary embodiment of the present invention;

FIG. 2 is a view illustrating an arrangement of direction measuring sensors according to an exemplary embodiment of the present invention;

FIG. 3 is a view illustrating a method of calculating angle information related to direction measuring sensors according to the present invention;

FIG. 4 is a view illustrating a method of calculating a predicated location of a self-traveling location according to the present invention;

FIG. 5 is a view illustrating a method of calculating a predicted location at a departure location of a self-traveling device according to the present invention; FIG. 6 is a block diagram of a self-traveling device

according to another exemplary embodiment of the present invention;

FIG. 7 is a flow chart illustrating a self-traveling method according to an exemplary embodiment of the present invention; and

FIG. 8 is a flow chart illustrating a self-traveling method according to another exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings . FIG. 1 is a block diagram of a self-traveling device according to an exemplary embodiment of the present invention.

Referring to FIG. 1, a self-traveling device 100 according to the present invention includes a distance measuring sensor 110, a direction tracker 12O ₇ a movement information calculator 130, a memory 140, a controller 150, a right-wheel motor 160, a left-wheel motor 170, first to fourth driving wheels 162, 164, 172, and 174, a cliff sensor 180, and a brake unit 190.

The distance measuring sensor 110 transmits an object sensing signal to a target or an object and receives the

object sensing signal reflected from the object, thereby- measuring a distance from the object. The object sensing signal is propagation, an ultrasonic wave for example, having a property of being reflected by the object. The distance measuring sensor 110 is installed at the rear surface, left side surface, and right side surface of the self-traveling device 100 to transmit the object sensing signal in the directions of the rear, left, and right sides of the self- traveling device 100 and to receive the object sensing signal from the object located therebehind. Namely, the distance measuring sensor 110 is installed at the rear surface, left side surface, and right side surface of the self-traveling device 100 and simultaneously transmits the object sensing signal at predetermined intervals. The distance measuring sensor 110 receives the object sensing signal reflected from the object and calculates a distance separated from the object. The predetermined intervals may be adjusted according to a moving speed of the object. If the moving speed of the object is fast, the period is set to be short, and the moving speed is slow, the period is set to be long. The object is a movable object, for example, a human body.

The distance measuring sensor 110 calculates a distance to the object reflecting the object sensing signal by the following Equation 1. [Equation 1]

D = (VxT)/2

In Equation 1, D is a distance between the distance measuring sensor 110 and the object, V is the velocity of the object sensing signal, and T is a moving time of the object sensing signal. The moving time T of the object sensing signal is obtained by subtracting a transmission time of the object sensing signal from a reception time of the object sensing signal.

The direction tracker 120 receives a radio signal transmitted by a transmitter carried by the object and calculates direction information based on the received radio signal. To this end, the direction tracker 120 includes a direction measuring sensor 122 and a direction information calculator 124. The direction measuring sensor 122 receives a radio signal transmitted by the transmitter carried by the object. The transmitter carried by the object may be placed at various locations from the self-traveling device because the object moves freely. Therefore, the self-traveling device according to the present invention includes a plurality of direction measuring sensors 122 to determine the direction of the transmitter carried by the object.

FIG. 2 is a view illustrating an arrangement of direction measuring sensors according to an exemplary embodiment of the present invention.

Referring to FIG. 2, 13 direction measuring sensors 122 are installed at a rear surface 210 of the self-traveling device 100 at constant intervals. Moreover, 13 direction measuring sensors 122 are installed at each of a left surface 230 and a right surface 250 based on a direction toward the rear surface 210 of the self-traveling device 100 at constant intervals .

The direction information calculator 124 calculates direction information of the transmitter carried by the object based on whether the radio signal of each of the direction measuring sensors 122 is received.

FIG. 3 is a view illustrating a method of calculating angle information related to direction measuring sensors according to an exemplary embodiment of the present invention. Referring to FIG. 3, angle information θ related to the direction measuring sensors 122 is calculated by the following Equation 2.

[Equation 2]

^{θ =} sm ( ^~ )

Here, r is a distance 310 from a central point of the self-traveling device to the direction measuring sensor 322, and d is a distance 320 between the direction measuring sensor 322 and an x-axis 330.

The direction information calculator 124 calculates

angles related to the direction measuring sensors 122 using Equation 2 or stores the angles in the memory so that the angles related to the direction measuring sensors 122 can be accessed from the memory. The direction information calculator 124 calculates direction information by the following Equation 3. [Equation 3]

It O

In Equation 3, θ is direction information, Si is a rotation angle indicated by each direction measuring sensor 122 receiving the radio signal, and n is the number of direction measuring sensors 122 receiving the radio signal.

The movement information calculator 130 calculates a predicted location of the object in front of moving direction of the object, based on the distance calculated by the distance measuring sensor 110, the direction information calculated by the direction tracker 120, and previous movement information, and calculates movement information for moving to the predicted location. The movement information includes individual running speeds of respective motors, a running speed, and rotation information for rotating the self- traveling device 100 to face toward the predicted location.

FIG. 4 is a view illustrating a method of calculating a predicated location according to the present invention.

Referring to FIG. 4, the movement information calculator 130 calculates a distance vector 411 indicating the distance and direction from a current location 410 of the self- traveling device to a previous location 420 thereof based on previous movement information. That is, the magnitude of the distance vector 411 is calculated by multiplying a distance measuring period of the distance measuring sensor 110 by the running speed of the movement information and direction information of the distance vector 411 is calculated through rotation information of the movement information. The movement information calculator 130 calculates the magnitude and direction of a distance vector 421 indicating the distance and direction to a previous location 440 of the object from the previous location 420 of the self-traveling device. The distance vector 421 is calculated through the distance measured by distance measuring sensor 110 and direction information calculated by the direction tracker 120 at the previous location 420 of the self-traveling device. Next, the movement information calculator 130 calculates the magnitude and direction of the distance vector 412 indicating the distance and direction to a current location 430 of the object from the current location 410 of the self-traveling device. The distance vector 412 is calculated through the distance measured by the distance measuring sensor 110 and direction information calculated by the direction tracker 120 at the

current location 410 of the self-traveling device. The movement information calculator 130 then calculates a distance vector 441 indicating the distance and magnitude from the previous location 440 of the object to the current location 430 of the object by the following Equation 4. [Equation 4] F1 = F2-F3-F4

Here, Vl, V2, V3, and V4 are distance vectors 441, 412, 411, and 421, respectively. The movement information calculator 130 calculates a predicted location 450 from the distance vector 441 by the following equation 5. [Equation 5] V5 = tV2 + V3 + V4 In Equation 5, V5 is a distance vector 413 from the current location 410 of the self-traveling device to the predicted location 450, t is a previously set constant greater than 1, and V2, V3, and V4 are distance vectors 441, 411, and 421, respectively. The predicted location is a point indicated by the distance vector 413 from the current location 410 of the self- traveling device 100. The constant t is set according to the moving speed of the object, that is, to be large if the moving speed is high and to be small if the moving speed is low. FIG. 5 is a view illustrating a method of calculating a

predicted location at a departure location of a self-traveling device according to the present invention.

Referring to FIG. 5, in an initial state, if the self- traveling device according to the present invention departs due to movement of the object, previous movement information, a distance calculated by the distance measuring sensor 110 at a previous location, and direction information calculated by the direction tracker 120 are not available. Therefore, the movement information calculator 130 calculates a predicted location by the following Equation 6. [Equation 6] V\ = -tV2+ V2

Here, Vl is a distance vector 512 from a departure location 510 of the self-traveling device to a predicted location 530 thereof, and V2 is a distance vector 511 from the departure location 510 to an object 520. The distance vector 511 is calculated by a distance measured by the distance measuring sensor 110 and direction information calculated by the direction tracker 120 during departure. The movement information calculator 130 calculates the distance vectors 413 and 512 to calculate a predicted location and uses the magnitude and direction of the distance vectors 413 and 512 as movement information for moving to the predicted location. Namely, the magnitude of the calculated distance vectors 413 and 512 is a distance to the predicted location

from a departure location and the direction of the calculated distance vectors 413 and 512 is converted into rotation information for rotating to face toward the predicted location.

The movement information calculator 130 calculates individual running speeds of the motors based on the calculated rotation information and calculates a running speed based on a difference value between from the self-traveling device to the calculated predicted location and a previously set distance .

The movement information calculator 130 calculates individual running speeds V _x and V ₂ of the right-wheel motor 160 and the left-wheel motor 170 according to a current running speed V of the motors and the direction information θ . If the direction information θ is negative, the movement information calculator 130 increases the current running speed V to obtain the individual running speed Vi and decreases the current running speed V to obtain the individual running speed V ₂ . If the direction information θ is 0, the movement information calculator 130 sets the individual running speeds V ₁ and V ₂ to the same speed as the current running speed V. If the direction information θ is positive, the movement information calculator 130 decreases the current running speed V to obtain the individual running speed Vi and increases the current running speed V to obtain the individual running speed V ₂ . When the movement information calculator 130 calculates the individual running speeds, an example of calculating an increased amount

and a decreased amount of the current running speed V is as indicated by the following Equation 7. [Equation 7] A = Vxθ/360 Here, δ is an absolute value of an increase or decrease in the running speed V.

As an example for calculating the individual running speeds, if the direction information θ is 0, the individual running speeds V ₁ and V ₂ are the running speed V, and if the direction information θ is -90, Vi is greater than V ₂ by 5/3.

When calculating a target running speed V , if a difference value obtained by subtracting the previously set distance from the distance calculated by the distance measuring sensor 110 is the same as the previously set distance, the movement information calculator 130 calculates the current running speed V as the target running speed V . The previously set distance can be adjusted by a user. If the difference value is negative, the movement information calculator 130 decreases the current running speed V of the motors to obtain the target running speed V and the difference value is positive, the movement information calculator 130 increases the current running speed V of the motors to obtain the target running speed V . An absolute value of an increased amount and a decreased amount of the running speed is proportional to an absolute value of the difference value and can be calculated by

the following Equation 8. [Equation 8] λ = Txa

Here, λ is an absolute value of an increased amount or a decreased amount of the current running speed of the motors, T is an absolute value of the difference value between the measured distance and the previously set distance, and a is a constant obtained by experimentally measuring an average walking speed of a person. The movement information calculator 130 calculates a distance from a bottom surface measured by the cliff sensor 180 and calculates a variation amount between the distance from the bottom surface measured by the cliff sensor 180 and a previously received distance. If the calculated variation amount is greater than a previously set value, the movement information calculator 130 generates a stop signal. The previously set value may be determined by a manufacturer or a user and may be set to one tenth of the size of each of the driving wheels 162, 164, 172, and 174. The movement information calculator 130 stores the movement information, the distance measured by the distance measuring sensor 110, and the direction information calculated by the direction tracker 120 in the memory 140. That is, the movement information calculator 130 stores the movement information including rotation information, individual running

speeds, and a running speed in the memory 140 and uses the movement information stored in the memory 140 as previous movement information when calculating a predicted location.

The controller 150 controls the driving of each motor based on the movement information calculated by the movement information calculator 130. The controller 150 changes direction by controlling the driving of each motor based on the individual running speed of each motor calculated by the movement information calculator 130. That is, the controller 150 controls the number of rotations of the right-wheel motor 160 and the left-wheel motor 170 using the individual running speeds Vi and V ₂ and changes direction so that the front surface of the self-traveling device is directed to the object carrying the transmitter. The controller 150 controls the driving of the right- wheel motor 150 and the left-wheel motor 160 based on the target travel speed V calculated by the movement information calculator 130 so that the self-traveling device can maintain a predetermined distance from the object. Namely, the controller 150 controls the numbers of rotations of the right-wheel motor 160 and the left-wheel motor 170 to be equal at the same target running speed V . Therefore, the self-traveling device moves while maintaining a previously set distance from the object.

The controller 150 controls the self-traveling device 100 to stop traveling thereof, upon receipt of the stop signal

generated by the movement information calculator 130. Namely, the controller 150 controls the brake unit 190 to stop driving the driving wheels 162, 164, 172, and 174.

The right-wheel motor 160 and the left-wheel motor 170 rotate the driving wheels 162, 164, 172, and 174 and the driving thereof is controlled by the controller 150. The first and second driving wheels 162 and 164 are rotated by the right- wheel motor 160 and the third and fourth wheels 172 and 174 are rotated by the left-wheel motor 170. The first and second driving wheels 162 and 164 may be comprised of track type wheels and the third and fourth wheels 172 and 174 may also be comprised of track type wheels. The right-wheel motor 160 and left-wheel motor 170 transmit rotation power through gear boxes to the first and second driving wheels 162 and 164, and the third and fourth driving wheels 172 and 174, respectively. Accordingly, since the motors are operated at maximum torque, the self-traveling device according to the present invention can carry 25 kg of baggage with low power. The cliff sensor 180 transmits infrared rays to a bottom surface and calculates a distance between the bottom surface and the cliff sensor 180 based on the time taken for the transmitted infrared rays to return to the cliff sensor 180. The cliff sensor 180 is installed at a lower surface of the self-traveling device and measures a distance from the cliff

sensor 180 to the bottom surface at predetermined intervals. For example, the time interval may be set to 0.2 seconds and a measuring period may be modified according to a running speed. The distance calculated by the cliff sensor 180 is input to the movement information calculator 130. If the bottom surface is judged to be stairs or a cliff through the cliff sensor 180, the self-traveling device is stopped, thereby preventing a fall.

The brake unit 190 stops the driving wheels 162, 164, 172, and 174. That is, the brake unit 190 stops driving the driving wheels 162, 164, 172, and 174 under the control of the controller 150 to stop the self-traveling device.

FIG. 6 is a block diagram of a self-traveling device according to another exemplary embodiment of the present invention.

Referring to FIG. 6, a self-traveling device 600 according to the present invention includes a distance measuring sensor 110, a direction tracker 120, a movement information calculator 130, a memory 140, a controller 650, a right-wheel motor 160, a left-wheel motor 170, first to fourth driving wheels 662, 664, 672, and 674, a cliff sensor 180, a brake unit 190, and a direction converting means 680.

In FIG. 6, the distance measuring sensor 110, the direction tracker 120, the movement information calculator 130, the memory 140, the right-wheel motor 160, the left-wheel

motor, the cliff sensor 180, and the brake unit 190 correspond to respective ones shown in FIG. 1.

The driving wheels 662 and 672 are front wheels of the self-traveling device, and the driving wheels 664 and 674 are back wheels of the self-traveling wheels.

The direction converting means 680 rotates the driving wheels 662 and 672 to change the direction of the self- traveling device.

The controller 650 controls the direction converting means 680 based on rotation information calculated by the movement information calculator 130 to convert the direction of the self-traveling device and controls the driving of the right-wheel and left-wheel motors 160 and 170 based on a travel speed calculated by the movement information calculator 130 to move the self-traveling device to a predicted location. Since the controller 650 converts the direction of the self-traveling device by controlling the direction converting means 680, the self-traveling device can rapidly and accurately convert the direction thereof to a predicted location. FIG. 7 is a flow chart illustrating a self-traveling method according to an exemplary embodiment of the present invention.

Referring to FIG. 7, the direction measuring sensor 122 receives a radio signal transmitted from a transmitter carried by an object (step S700) . The direction information calculator

124 calculates direction information based on the radio signal received by the direction measuring sensor 122 (step S710) . The distance measuring sensor 110 transmits an object sensing signal to the object and receives the object sensing signal reflected from the object, to measure a distance separated from the object (step S720) . The object sensing signal is propagation, an ultrasonic wave for example, having a property of being reflected by the object. The movement information calculator 130 calculates a predicated location located in front of the object from the moving direction of the object, based on the distance measured by the distance measuring sensor 110, the direction information calculated by the direction information calculator 124, previous rotation information, and a running speed (step S730) . Next, the movement information calculator 130 calculates rotation information for rotating to face toward the predicted location, individual running speeds of respective motors based on the rotation information, and a running speed (step S740) . The running speed is calculated by a difference value between a distance from the self-traveling device to the predicted location and a previously set distance. The movement information calculator 130 stores in the memory 40 the calculated rotation information, the individual running speeds, the running speed, the distance calculated by the distance measuring sensor 110, and the direction information calculated by the direction information calculator 124.

The controller 150 controls the driving of the right- wheel and left-wheel motors 160 and 170 based on the individual running speeds of the motors calculated by the movement information calculator 130 (step S750) . Next, the controller 150 controls the driving of the right-wheel and left-wheel motors 160 and 170 based on the running speed calculated by the movement information calculator 130 (step S760) .

The cliff sensor 180 transmits infrared rays to the bottom surface and calculates a distance between the bottom surface and the cliff sensor 180 based on the time taken for the transmitted infrared rays to return to the cliff sensor 180

(step S770) . The movement information calculator 130 calculates a variation amount between the measured distance and a previously measured distance and generates a stop signal when the calculated variation amount is greater than a previously set value (step S780) . If the stop signal is generated, the controller 150 stops the self-traveling device from traveling (step S790) .

FIG. 8 is a flow chart illustrating a self-traveling method according to another exemplary embodiment of the present invention.

Referring to FIG. 8, the direction measuring sensor 122 receives a radio signal transmitted from a transmitter carried by an object (step S800) . The direction information calculator 124 calculates direction information based on the radio signal

received by the direction measuring sensor 122 (step S810) . The distance measuring sensor 110 transmits an object sensing signal to the object and receives the object sensing signal reflected from the object, to measure a distance separated from the object (step S820) . The object sensing signal is propagation, an ultrasonic wave for example, having a property of being reflected by the object. The movement information calculator 130 calculates a predicated location located in front of the object from the moving direction of the object, based on the distance measured by the distance measuring sensor 110, the direction information calculated by the direction information calculator 124, previous rotation information, and a running speed (step S830) . Next, the movement information calculator 130 calculates rotation information for rotating to face toward the predicted location, and calculates a running speed based on a difference value between a distance from the self-traveling device to the predicted location and a previously set distance (step S840) . The movement information calculator 130 stores in the memory 40 the calculated rotation information, the running speed, the distance calculated by the distance measuring sensor 110, and the direction information calculated by the direction information calculator 124.

The controller 650 controls the direction converting means 680 based on the rotation information calculated by the movement information calculator 130 (step S850) . Next, the

controller 150 controls the driving of the right-wheel and left-wheel motors 160 and 170 based on the running speed calculated by the movement information calculator 130 (step S860) . The cliff sensor 180 transmits infrared rays to the bottom surface and calculates a distance between the bottom surface and the cliff sensor 180 based on the time taken for the transmitted infrared rays to return to the cliff sensor 180 (step S870) . The movement information calculator 130 calculates a variation amount between the measured distance and a previously measured distance and generates a stop signal when the calculated variation amount is greater than a previously set value (step S880) . If the stop signal is generated, the controller 150 stops the self-traveling device (step S890) . The self-traveling device according to the present invention includes a distance measuring sensor, a direction measuring sensor, a direction information calculator, a movement information calculator, a controller, a right-wheel motor, a left-wheel motor, driving wheels, a cliff sensor, and a brake unit. The distance measuring sensor, movement information calculator, controller, right-wheel motor, left- wheel motor, driving wheels, cliff sensor, and brake unit correspond to the distance measuring sensor 110, movement information calculator 130, controller 150, right-wheel motor 160, left-wheel motor 170, driving wheels 162, 164, 172, and

174, cliff sensor 180, and brake unit 190 included in the self- traveling device according to the present invention. Further, the direction measuring sensor and the direction information calculator correspond to the direction measuring sensor 122 and the direction information calculator 124 included in the self- traveling device according to the present invention.

The self-traveling device according to the present invention includes a distance measuring sensor, a direction measuring sensor, a movement information calculator, a controller, a right-wheel motor, a left-wheel motor, driving wheels, a cliff sensor, a brake unit, and a direction converting means. The driving wheels, controller, and direction converting means correspond to the driving wheels 662, 664, 672, and 674, the controller 650, and the direction converting means 680 included in the self-traveling device according to the present invention, and therefore a detailed description thereof is omitted.

The present invention may be achieved by codes which are readable by a computer on a recording medium. The recording medium which can be read by the computer includes all types of recording devices in which data which can be read by the computer is recorded. For example, the recording medium includes read-only memories (ROMs) , random access memories (RAMs) , compact disk read-only memories (CD-ROMs) , magnetic tapes, floppy disks, optical data storage devices. The

recording medium also includes a form of carrier waves (for example, transmission over the Internet) . The recording medium which can be read by the computer is distributed in a computer device connected through a network and stores codes which can be read by the computer by a distribution method.

Although the exemplary embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

According to the self-traveling device and method of the present invention, a moving direction and moving speed of an object along the movement of the object are accurately sensed so that the self-traveling device moves while keeping a constant distance in front of the object. Accordingly, the self-traveling device according to the present invention can carry baggage, etc. without direction setting or direction adjustment by a user. Especially, if the self-traveling device according to the present invention is used instead of a conventional shopping cart in a large store, since the self- traveling device is moved along the movement of a user, the inconvenience of having to push the shopping cart can be solved. If the self-traveling device according to the present invention is used instead of a travel bag in an airport, the

inconvenience of a passenger having to move the bag is solved, and theft, loss, and damage of the bag can be prevented because the self-traveling device moves within the passenger' s view.