KR101450843B1 - Group Robot System and Control Method thereof - Google Patents

Abstract

The present invention relates to a group robot system and a method of controlling the same. According to the present invention, the method of controlling the group robot system formed of multiple robots includes the steps of: determining whether an obstacle exists or not by a preceding robot among the robots; setting a communications range of the preceding robot as one among at least two communications ranges according to whether an obstacle exists or not; calculating the distance between the preceding robot and a following robot; and comparing the calculated distance between the two robots with the set communications range of the preceding robot to control the path of the following robot to enable the following robot to exist within the communications range of the preceding robot. According to the present invention, multiple robots can communicate and be connected more easily.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a group robot system,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a community robot system and a control method thereof, and more particularly, to a community robot system and a control method thereof that can control a movement path for a plurality of robots constituting a community and communicate with each other.

Generally, a community robot system can be used in an industrial environment such as an army, a power plant, or a factory to perform various tasks, or can be used for entertainment such as a biped robot type football system. Recently, the robot robot system based on this network has been widely used as a field for carrying out various researches on the technology of combining the motion patterns and characteristics of natural living organisms in recent years.

Conventionally, a potential field is calculated to control a movement path for a plurality of robots constituting a cluster. The method of controlling the movement path of the robot by calculating the potency field is a method of calculating the movement path to the destination while keeping the formation of the cluster robots assuming the virtual force around the robots.

However, in the conventional method, there is a problem that the possibility of collision between neighboring locomotion robots increases as the number of cluster robots forming a certain size increases. Also, if a certain distance is maintained to reduce the possibility of collision, communication between locomotion robots becomes unstable there was.

In addition, there is a problem in that the prior information about the moving region of the cluster robots must be stored in advance.

In addition, since the algorithm for computing the operation algorithm of the cluster robot is complicated, a load may be generated in the processor that performs the operation algorithm, and at the same time, it takes a long time to control the movement path of the cluster robot due to the complex operation algorithm .

Korea Patent Publication No. 2010-0086093

Therefore, a problem to be solved by the present invention is to set the communication range of the preceding robot differently according to whether an obstacle exists or not, and to control the trailing robot so that the trailing robot exists in the communication range of the set preceding robot And a control method thereof.

According to an embodiment of the present invention, there is provided a method of controlling a system for collective robots comprising a plurality of robots, the method comprising the steps of: determining whether a preceding robot among the plurality of robots has an obstacle; Setting a communication range of the preceding robot to one of at least two communication ranges, calculating a distance between the preceding robot and the following robot, comparing the calculated distance between the two robots and the communication range of the set preceding robot And controlling the path of the trailing robot so that the trailing robot exists within the communication range of the preceding robot.

The at least two communication ranges include a maximum communication range and a safety communication range, and the safety communication range may be an area within the maximum communication range and a distance smaller than the distance from the obstacle.

Wherein the step of setting the communication range of the preceding robot to one of at least two communication ranges according to the presence or absence of the obstacle includes setting the communication range of the preceding robot to the maximum communication range if the obstacle does not exist, The communication range of the preceding robot can be set as the safety communication range.

The preceding robot transmits information on the set communication range to the trailing robot, and the trailing robot can calculate the communication sustainable range with the preceding robot using the communication range, position and angle of the preceding robot.

Wherein the step of controlling the path of the trailing robot such that the trailing robot exists within the communication range of the preceding robot includes setting a moving target point of the trailing robot so that the time for the trailing robot to move into the communication range of the preceding robot is minimized Step < / RTI >

The moving target point may be set using an angle at which the trailing robot rotates to be within the communication range of the preceding robot and a straight line distance at which the trailing robot moves.

According to an embodiment of the present invention, a community robot system composed of a plurality of robots includes a preceding robot for determining whether an obstacle exists or not, and setting a communication range to any one of at least two communication ranges according to the existence of the obstacle, And a trailing robot which calculates the distance between the preceding robots and compares the calculated distance between the preceding robots and the communication range of the set preceding robot and controls the path so as to be within the communication range of the preceding robot.

The at least two communication ranges include a maximum communication range and a safety communication range, and the safety communication range may be an area within the maximum communication range and a distance smaller than the distance from the obstacle.

The preceding robot can set the communication range of the preceding robot to the maximum communication range if the obstacle does not exist and set the communication range of the preceding robot to the safety communication range when the obstacle exists.

The preceding robot transmits information on the set communication range to the trailing robot, and the trailing robot can calculate the communication sustainable range with the preceding robot using the communication range, position and angle of the preceding robot.

The trailing robot can set the moving target point so that the time for moving to the communication range of the preceding robot is minimized.

The moving target point may be set using an angle at which the trailing robot rotates to be within the communication range of the preceding robot and a straight line distance at which the trailing robot moves.

According to the system and the control method of the present invention, it is possible to set the communication range of the preceding robot differently according to the presence of the obstacle, and to set the communication range of the trailing robot so that the trailing robot exists in the communication range of the set preceding robot There is an advantage that communication can be easily established between a plurality of robots by controlling the paths.

In other words, if the communication range of the preceding robot is set differently according to the existence of the obstacle and is provided to the trailing robot, the trailing robot calculates the communication sustainable range with the preceding robot and moves so as to secure communication visibility with the preceding robot. There is an advantage that communication can be more smoothly performed between robots.

Also, there is an advantage that communication can be established more securely between a plurality of robots even when moving in a region where communications are interrupted including obstacles.

In addition, there is an advantage that a moving target point of the trailing robot can be set and communication can be established in a shortest time between a plurality of robots.

Accordingly, there is an advantage that communication visibility and communication connection stability can be more easily secured between a plurality of robots constituting the cluster.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a cluster robot system according to an embodiment of the present invention; FIG.
2 is a view showing a plurality of communication ranges that can be set in a preceding robot according to an embodiment of the present invention.
3 is a diagram illustrating a communication range set in a preceding robot when there is no obstacle according to an embodiment of the present invention.
4 is a diagram showing a communication range set in a preceding robot when there is an obstacle according to another embodiment of the present invention.
5A to 5D are diagrams showing a moving direction of a preceding robot according to a communication range change.
6 is a view showing a setting of a moving target point for communicating the preceding robot and the trailing robot in the shortest time.
FIG. 7 is a flowchart illustrating a process of controlling a community robot system according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

1 is a block diagram of a system for collective robots according to an embodiment of the present invention.

As shown in FIG. 1, the community robot system 100 may be composed of a plurality of robots including the preceding robot 120 and the trailing robots 140 (140a to 140n).

The preceding robot 120 is a robot that is positioned at the foremost position among the plurality of clusters and plays a role of a master. The preceding robot 120 continuously communicates with the trailing robot 140 and connects the trailing robot 140 to a destination, So that the path of the trailing robot 140 can be controlled.

The trailing robot 140 continuously communicates with the preceding robot 120 and can move to a destination by receiving position information or movement information provided by the preceding robot 120.

The preceding robot 120 and the trailing robot 140 may be implemented with substantially the same configuration, but any one of the plurality of robots may be set as the preceding robot by the user's selection. That is, the robot having the specific information specified by the user among the plurality of robots having the unique information may be the leading robot 120, and the remaining robots may be the trailing robot 140.

More specifically, the preceding robot 120 includes a preceding sensing unit 121, a preceding position determining unit 122, and a preceding control unit 123 The trailing robot 140 may include a trailing sensing unit 141, a trailing positioning unit 142, and a trailing control unit 143.

The pre-detection unit 121 and the post-detection unit 141 may include various sensors such as a camera and an infrared sensor, and may collect environmental information of a region to be searched by the robot.

The pre-position detection unit 122 and the post-position detection unit 142 may include a Global Positioning System (GPS) receiver and may be a GPS based navigation technique or a Simultaneous Localization And Mapping So that the robot can grasp its own position.

The preceding controller 123 controls the leading robot 120 in general and the trailing controller 143 controls the trailing robot 140 in general so that the robot moves to a destination to which the robot wants to move while avoiding an obstacle, To be performed. The predecessor control unit 123 grasps environment information and location information of a search area including, for example, a position and a distance of an obstacle, using the pre-detection unit 121 and the preceding position determination unit 122, The environment information and the position information of the area are transmitted to the trailing robot 140 connected to the communication so that the trailing robot 120 and the trailing robot 140 can move to the destination to avoid the collision with the obstacle or another robot.

Hereinafter, a process of establishing communication between a plurality of robots constituting a cluster will be described in more detail.

First, in order to establish a communication connection between a plurality of robots, the following can be assumed.

The robot can be made in the shape of a circle, and the model for the linear movement and the rotation movement of the robot can be assumed as a simplified instant model (Simplify Instantaneous Model). It is also assumed that communication between a plurality of robots can be both multicast (multi-cast) and broadcast (broad-cast), and there is no communication delay. Information on the position and angle of the robot can be transmitted to all the robots in real time.

Referring to FIG. 2, the communication range of the preceding robot 120 includes a maximum communication range ( _rmax ), a safety communication range The range (d _max ) and the minimum communication range (d _min ). Here, the maximum communication range ( _rmax ) can be set in advance as the widest area in which the preceding robot 120 can communicate with the trailing robot 140. [ Secure communication range (d _max) is an area at the maximum communication range smaller distance than the distance of the obstacle and to stay within the (r _max), can be made can be varied. The minimum communication range d _min corresponds to about 1.5 times the diameter of the preceding robot 120 as the area where the preceding robot 120 can communicate with the obstacle or other robot in order to prevent collision with other robots. Can be set.

FIG. 3 is a diagram showing a communication range set in a preceding robot in the absence of an obstacle according to an embodiment of the present invention. FIG. 4 is a diagram showing a communication range set in a preceding robot when there is an obstacle according to another embodiment of the present invention. Fig.

The preceding robot 120 may include a laser ranging finder (LRF), an ultrasonic sensor, or the like. The preceding robot 120 can measure the distance from the sensor to the surrounding obstacle and determine whether or not there is an obstacle. The preceding robot 120 can set the communication range to any one of a plurality of communication ranges according to the presence of an obstacle. That is, if the preceding robot 120 determines that there is an obstacle around it, if the obstacle is present or the obstacle exists, if the position of the obstacle is out of the maximum communication range ( _rmax ), the communication range of the preceding robot 120 is the maximum communication range r _max ) and the safety communication range (d _max ) to the maximum communication range (r _max ).

If there is no obstacle around the preceding robot 120 as shown in FIG. 3, the communication range of the preceding robot 120 can be determined using (Expression 1).

(Equation 1)

Here, d _{max, A} is the safety communication range of the preceding robot, r _{max, A} is the maximum communication range of the preceding robot, and the communication range of the preceding robot 120 is the maximum communication range (r _{max, A} ), And the safety communication range (d _{max, A} ) of the preceding robot 120 can be the maximum communication range (r _{max, A} ).

On the other hand, the prior robot 120 can be set when an obstacle exists within the maximum communication range (r _max) of the leading robot (120), the communication range as a safe communication range (d _max).

4, when the preceding robot 120 meets the obstacle P as it moves, the preceding robot 120 measures the distance to the obstacle P, and if the distance is smaller than the maximum communication range r _max , the preceding robot 120 converts and sets the communication range from the maximum communication range (r _max ) to the safety communication range (d _max ). At this time, the safety communication range (d _max) is about the prior robot 120 to source a distance between the leading robot 120 and the obstacle can be set to the radial inner region. In contrast, the position and shape such as to a region except for the portion that is covered by an obstacle at the maximum communication range (r _max) may be set in consideration of the obstacle safety communication range (d _max).

As described above, the communication range can be changed while meeting the obstacle according to the direction in which the preceding robot 120 moves, and the safety communication range can be determined as shown in (Equation 2).

(Equation 2)

Here, dmax _{, A} can be set by the safety communication range of the preceding robot 120 and? Of? _{Max, A} , which is the maximum communication range. DELTA is a value related to the distance between the preceding robot 120 and the obstacle, and can be expressed in a range of 0 to 1. However, the preceding robot 120 can keep the distance from the obstacle P such that the safety communication range d _max is not smaller than the minimum communication range d _min .

Thus prior robot 120 is secure communication range of the communication range based on the presence of obstacles (d _max), the maximum communication range (r _max) and can be determined by any one of at least the communication range (d _min), and the determined preceding robot The behavior control of the trailing robot 140 according to the communication range of the robot 120 can be performed as follows.

The coordinates of the preceding robot 120 and the trailing robot and the distance l between the (140), preceding the robot 120 when the (x _c, y _c) and the coordinates of the trailing robot 140. (x _f, y _f) , The distance l between the preceding robot 120 and the trailing robot 140 is calculated using the formula 3 and the distance l between the calculated leading robot 120 and the trailing robot 140 and the distance 120) so as to control the behavior of the trailing robot 140 so that the trailing robot 140 is within the communication range of the preceding robot 120. [

(Equation 3)

The trailing robot 140 compares the distance l with the preceding robot 120 and the communication range of the preceding robot 120 when the communication range of the preceding robot 120 is determined. In this case, it is determined whether the distance l to the preceding robot 120 is within the communication range of the preceding robot 120, and the process proceeds to the next step. If the trailing robot 140 is positioned within the communication range of the preceding robot 120, the trailing robot 140 is in a state in which communication with the preceding robot 120 is smooth and the preceding robot 120 moves, The communication link with the preceding robot 120 can be performed until the robot 120 is changed. In contrast, if the trailing robot 140 is not located within the communication range of the preceding robot 120, the trailing robot 140 moves within the communication range of the preceding robot 120 to maintain smooth communication with the preceding robot 120 You can control the path to do so.

5A to 5D are views showing a moving direction of a preceding robot according to a communication range change.

5A is a diagram showing the communication range of the preceding robot 120 which has encountered the obstacle P for the first time. The communication range of the preceding robot 120 can be set to the safety communication range (d _max ) 140 can be moved to exist within the safety communication range (d _max ) of the preceding robot 120. 5B shows that the communication range is changed from the safety communication range (d _max ) to the minimum communication range (d _min ) in the process of avoiding the obstacle P and moving the preceding robot 120. 5C shows that the preceding robot 120 avoids the obstacle P while keeping the communication range at the minimum communication range d _min . At this time, the trailing robot 140 moves to the minimum communication range is located within the (d _min), thus the trailing robot 140, communication visibility of the preceding robot 120 as located within the minimum communication range (d _min), the trailing robot 140 of the leading robot 120 . FIG. 5D shows that the preceding robot 120 and the following robot 140 are communicating with each other while passing through the obstacle P. FIG.

If the preceding robot 120 determines the communication range and provides the communication range to the trailing robot 140 according to the presence or absence of the obstacle, the trailing robot 140 uses the communication range, position, and angle of the preceding robot 120 The communication holdable range is calculated and moved to the calculated communication holdable range, thereby enabling a more smooth communication connection. In addition, it is possible to connect the communication more securely when moving in an area where communication disruption including an obstacle is expected.

Hereinafter, a method in which the trailing robot moves in the shortest time within the communication range of the preceding robot will be described.

First, in order for the trailing robot 140 to move within the communication range of the preceding robot 120, the moving target points P1, P2, and P3 are set such that the traverse robot 140 moves the least amount of time. Here, the moving target points P1, P2, and P3 can be determined using the angle at which the trailing robot 140 is rotated so that the trailing robot 140 exists within the communication range of the preceding robot 120 and the straight line distance at which the trailing robot 140 moves.

6 is a view showing a setting of a moving target point for communication connection of the preceding robot and the trailing robot in the shortest time.

6, in order for the preceding robot 120 and the trailing robot 140 to communicate with each other, the trailing robot 140 must move within the communication range of the preceding robot 120, It is assumed that the point is the minimum. _{Here, ω B, υ B, θ} B is a rotational speed (ω _B), linear velocity (υ _B), the angle (θ _B) of the trailing robot 140, respectively.

The formula for obtaining the total travel time of the trailing robot 140 is expressed as follows.

(Equation 4)

t _tot = t _rot + t _lin

Here, the total movement time t _tot can be expressed as a sum of the rotation movement time t _rot and the linear movement time t _lin .

The rotational movement time can be calculated using Equation (5), and the rotational time can be obtained by dividing the rotational angle of the trailing robot 140 by the rotational velocity.

(Equation 5)

t _rot = (? _{d -} ? _B ) /? _B =? _t /? _B

The equation for obtaining the linear movement time (t _lin ) is shown in Equation (6).

(Equation 6)

t _lin = d / υ _B

(Equation 5) and (Equation 6) are substituted into Equation (4), the total shift time can be expressed by Equation (7) below.

(Equation 7)

t _tot = (? _t /? _B ) + (d /? _B )

On the other hand, in order to obtain the optimal movement time, that is, the shortest movement time, the optimum? _T for the trailing robot 140 to move within the communication range of the preceding robot 120 should be obtained.

Here, the method for obtaining the optimal θ _t can be obtained by using the sum of the rotation speed and the linear speed as described above. The total travel time of the trailing robot 140 can be obtained by calculating the rotation angle and the straight line distance by calculating the straight line distance that the trailing robot 140 is located within the communication range of the preceding robot 120. [

The straight-line distance d can be obtained by using the second law of cosine as shown in equation (8).

(Equation 8)

(8) is summarized with respect to the straight-line distance (d), the equation (9) is obtained.

(Equation 9)

(D) is obtained by using the formula of the root, the following equations (10) and (11) are obtained.

(Equation 10)

(Equation 11)

The total travel time is obtained using the obtained straight line distance d, as shown in Equation (12).

(Equation 12)

On the other hand, if the rotation time of the preceding robot 120 and the trailing robot 140 for obtaining the optimal θ _t is sufficiently larger than the linear movement time, the linear movement time of the trailing robot 140 can be neglected because it is relatively small , The rotation time of the trailing robot 140 can be ignored if the linear movement time of the preceding robot 120 and the trailing robot 140 is sufficiently larger than the rotation time.

FIG. 7 is a flowchart illustrating a process of controlling a community robot system according to an embodiment of the present invention.

When 7, the leading robot 120 is confirmation that the preceding obstacle around the robot 120 while the mobile, and the obstacle is present is determined that the obstacle is within the maximum communication range (r _max) (S701).

The maximum communication range when it is determined to not exist within the (r _max) (S701-N), the communication range of the leading robot (120) up to the communication range of not present an obstacle in the step (S701) an obstacle preceding the robot 120 set (r _max) and (S702), puts the safety communication range (d _max) at the maximum communication range (r _max). Then go up to the communication range (r _max) trailing the robot 140 to the trailing robot 140 is present in the prior robot 120 thereby (S703).

Up to the communication range of the then leading robot (120) (r _max) in the trailing robot 140, it is determined whether the present (S704) the judgment result, the maximum communication range of the leading robot (120) (r _max) in the trailing robot (Step S705) if the trailing robot 140 has reached the final target point.

If the trailing robot 140 does not exist in the maximum communication range r _max of the preceding robot 120 or if the trailing robot 140 does not reach the final target, a new trailing robot is added (S706).

Meanwhile, when determining that an obstacle in the step (S701) existing within the maximum communication range (r _max) of the leading robot (120) (S701-Y) , the communication range of the safety communication range of the leading robot (120) (d _max) and setting (S707), moving the leading robot 120 of the secure communication range trailing robot 140 to the robot trailing is present in the (d _max) 140 thereby (S708) a.

Then, trailing in the safety communication range (d _max) of the leading robot 120, the robot 140 determines whether the present (S709) the judgment result, the safety communication range of the leading robot (120) (d _max) in the trailing robot (Step S706), the trailing robot 140 determines whether the trailing robot 140 reaches a final target point.

If, in the secure communication range trailing (d _max), the robot 140 is not present or trailing robot 140 of the leading robot (120) If the end has not been reached to the target position, it adds the new trailing robot (S706).

In this way, the prior robot 120 is the maximum communication range of the communication range based on the presence of obstacles on the go (r _max) and the security communication range (d _max) may be set from the one which, if of course, requires a minimum the communication range (r _min ) can also be set. According to such a setting, the path is controlled such that the trailing robots 140 are within the communication range of the preceding robot 120, so that the communication connection can be maintained continuously between the plurality of robots. Also, since the trailing robot 140 can be moved within the communication range of the preceding robot 120 in the shortest possible time, the trailing robot 120 and the trailing robot 140 can be communicatively connected within the shortest time.

Embodiments of the present invention include a computer-readable medium having program instructions for performing various computer-implemented operations. This medium records a program for executing the control method of the community robot system described above. The medium may include program instructions, data files, data structures, etc., alone or in combination. Examples of such media include magnetic media such as hard disks, floppy disks and magnetic tape, optical recording media such as CD and DVD, programmed instructions such as floptical disk and magneto-optical media, ROM, RAM, And a hardware device configured to store and execute the program. Or such medium may be a transmission medium, such as optical or metal lines, waveguides, etc., including a carrier wave that transmits a signal specifying a program command, data structure, or the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

100: Cluster Robot System
120: a preceding robot 121:
122: preceding position determination unit 123:
140: trailing robot 141: trailing sensor
142: trailing position determination unit 143:

Claims (12)

A method for controlling a system of a plurality of robots,
Determining whether a preceding one of the plurality of robots has an obstacle,
Setting a communication range of the preceding robot to any one of at least two communication ranges according to whether or not the obstacle exists;
Calculating a distance between the preceding robot and the following robot, and
Controlling the path of the trailing robot so that the trailing robot exists within the communication range of the preceding robot by comparing the calculated distance between the two robots and the communication range of the set preceding robot
/ RTI >
Wherein the at least two communication ranges include a maximum communication range and a safety communication range, the safety communication range being an area within the maximum communication range and a distance smaller than the distance from the obstacle
Control method of cluster robot system. delete The method of claim 1,
Wherein the step of setting the communication range of the preceding robot to any one of at least two communication ranges according to whether or not the obstacle exists,
If the obstacle does not exist, sets the communication range of the preceding robot to the maximum communication range,
And sets the communication range of the preceding robot to the safety communication range when the obstacle exists. The method of claim 1,
The preceding robot,
Transmits information on the set communication range to the trailing robot,
The trailing robot includes:
And calculating a communication sustainable range with the preceding robot using the communication range, position, and angle of the preceding robot. The method of claim 1,
Wherein the step of controlling the path of the trailing robot such that the trailing robot exists within the communication range of the preceding robot comprises:
And setting a moving target point of the trailing robot so that a time during which the trailing robot moves within a communication range of the preceding robot is minimized. The method of claim 5,
The moving target point,
Wherein the angle of rotation of the trailing robot and that of the trailing robot are set so as to be within the communication range of the preceding robot. 1. A community robot system comprising a plurality of robots,
A preceding robot for determining whether an obstacle exists or not and setting a communication range to any one of at least two communication ranges according to whether or not the obstacle exists,
A trailing robot for calculating a distance between the preceding robots and comparing the distance between the calculated preceding robot and the communication range of the set preceding robot and controlling the path so as to be within the communication range of the preceding robot
/ RTI >
Wherein the at least two communication ranges include a maximum communication range and a safety communication range, the safety communication range being an area within the maximum communication range and a distance smaller than the distance from the obstacle
Community Robot System. delete 8. The method of claim 7,
The preceding robot,
If the obstacle does not exist, sets the communication range of the preceding robot to the maximum communication range,
And sets the communication range of the preceding robot to the safety communication range when the obstacle exists. 8. The method of claim 7,
The preceding robot,
Transmits information on the set communication range to the trailing robot,
The trailing robot includes:
And calculates a communication sustainable range with the preceding robot using the communication range, position, and angle of the preceding robot. 8. The method of claim 7,
The trailing robot includes:
And sets a moving target point so that a time to move within the communication range of the preceding robot is minimized. 12. The method of claim 11,
The moving target point,
Wherein the robot is set using an angle at which the trailing robot is rotated so as to be within the communication range of the preceding robot and a straight line distance at which the trailing robot moves.

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