JPH07271434A - Environment map preparing method by plural mobile robots - Google Patents

Abstract

PURPOSE:To prepare an entire environment map by synthesizing respective maps without damaging the merit of environment map preparation using plural robots. CONSTITUTION:Both robots A and B arrive at points Pa' and Pb' and get close each other, the robot A measures the position of the robot B and gets a vector (c) expressing the relative position with the robot A itself. Further, the robot A is provided with a vector (b) expressing the position of the robot B on an individual coordinate system Bxy from the robot B, calculates a vector (d) expressing the relative position of the individual coordinate system Bxy corresponding to an individual coordinate system Axy from the vectors (b) and (c) and a vector (a) expressing its own position on the individual coordinate system Axy, calculates a vector (e) expressing its own position on the individual coordinate system Bxy and replaces it with the vector (a) expressing its own position on the individual coordinate system Axy. The robot A converts the respective maps prepared on the individual coordinate system Axy to the maps based on the individual coordinate system Bxy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a case where a plurality of mobile robots (hereinafter, simply referred to as robots) simultaneously act in an environment in which various objects exist and create a map of the environment. The present invention relates to a method for generating a map of the entire environment by synthesizing maps created by a robot based on individual coordinate systems.

[0002]

2. Description of the Related Art A robot that creates a map of the environment surrounding it by acting in the environment itself is referred to as "robot environment map creation".

When a plurality of robots make an environmental map, each robot first sets an individual coordinate system (called an individual coordinate system). Next, the robot acts in the environment, and in the process, observes surrounding objects using a TV camera or the like as a sensor, and fills in contour lines of those objects on the individual coordinate system. The position of the robot itself on the individual coordinate system is recognized by dead reckoning. Dead reckoning means that when the robot starts from a certain reference point and moves, for example, if it moves by wheels, the value obtained by multiplying the rotation speed of the wheel by the circumference of the wheel is regarded as the movement distance, and the reference point This is a method of recognizing one's position with respect to.

A map of the entire environment can be obtained by synthesizing all the maps (called individual maps) created by each robot in this way. At this time, the individual maps to be combined need to be based on a common coordinate system. Therefore, the individual coordinate system initially set by each robot needs to be integrated into a single coordinate system when synthesizing individual maps.

[0005]

In the prior art relating to the environmental map creation by a plurality of robots, when the individual coordinate systems of the robots are different from each other, they are integrated and converted into a common coordinate system. No such method has been considered. That is, it is assumed that all individual coordinate systems are the same coordinate system from the beginning.

In the prior art, if all the individual coordinate systems are to be unified to the same coordinate system, all the robots must be gathered at the same place and the coordinate system must be set at the time of starting the environment map creation. This method is not only difficult to implement, but also has the advantage of using multiple robots, that is, the time required to create an environmental map is increased by combining individual maps created by multiple robots at different locations in the environment. There is a problem that it is not possible to make full use of the advantages such as being shortened.

An object of the present invention is to integrate a plurality of individual coordinate systems without compromising the advantage of creating an environment map using a plurality of robots, and combine the individual maps to create a map of the entire environment. It is to provide a method for creating an environmental map by a robot.

[0008]

According to the method for creating an environment map by a plurality of mobile robots of the present invention, while the first robot is moving, the mounted sensor detects the approach of a second robot having a different individual coordinate system. When I did, the first robot
The position of the second robot is measured by a sensor, and a vector c representing the relative position to the self on the first coordinate system which is the individual coordinate system of the second robot is obtained. The first robot transmits the vector b representing the position of its own on the second coordinate system, which is the system, and the inverse vector −b of the vector c and the vector b, and its position on the first coordinate system. By adding the represented vector a,
The vector d representing the relative position of the second coordinate system to the first coordinate system is obtained, or the first robot sends the vector c and the vector a to the second robot, and the second robot uses the vector By adding c and the inverse vector −a of vector a and vector b, a vector d ′ representing the relative position of the first coordinate system to the second coordinate system is obtained,
Each robot has a coordinate system integration step that uses one individual coordinate system as a common individual coordinate system and integrates the other individual coordinate system into it.Each robot recognizes the position of the object on its own individual coordinate system by the mounted sensor. Then, the individual map is created, and when two robots having different individual coordinate systems approach each other, the coordinate system integration step is executed to integrate one individual coordinate system into the other individual coordinate system, If there are other robots that have the same individual coordinate system as the above individual coordinate system, all the robots are allowed to perform the coordinate system integrating step to integrate the individual coordinate system of the robot into the other individual coordinate system. Iterate until each robot has a common individual coordinate system of, and from the vector expressing the position of the object on its own individual coordinate system, each robot expresses the relative position of the common individual coordinate system with respect to its own individual coordinate system. By subtracting the vector d or d ′ obtained in the coordinate system integration step and converting the vector representing the position of the object into a vector on a common individual coordinate system, the individual map of the self is displayed on the common individual coordinate system. In the coordinate system integration step or after the unique common individual coordinate system is obtained, the individual maps on the unique common coordinate system are integrated.

[0009]

As a premise of the present invention, all of a plurality of robots (hereinafter, referred to as a robot group) for creating an environment map include a measurement function for measuring the positions of other robots in the vicinity and the measured position. It is necessary to have a communication function for transmitting information to other robots.

The first feature of the present invention is that if the two robots in the robot group come close to each other and the individual coordinate systems of the robots are different from each other, the above measuring function is used. One robot (called the measurement robot) measures the position of the other robot (called the measured robot), and based on the measured values, one robot sets its own individual coordinate system to that of the other robot. It is to convert to the same coordinate system as the coordinate system (common individual coordinate system). At this time, the robot that transforms the individual coordinate system may be either a measurement robot or a measured robot.

A second feature of the present invention is that one of a plurality of robots having the same individual coordinate system (referred to as a group of robots of the same system) performs its own individual coordinate system by the operation described in the first feature. If is transformed, all other robots belonging to the same robot group also transform their respective individual coordinate systems to maintain the sameness of the individual coordinate systems in the same robot group.

In order to take advantage of the use of a plurality of robots, it is desirable that the individual maps created by them do not overlap. Therefore, it is desirable that the individual robots are evenly distributed in the environment at the time of starting the environment map creation. The robots evenly distributed in the environment set the individual coordinate system at each point and then start to create individual maps. Therefore, the individual coordinate systems of the individual robots are all different at the time when the environmental map creation is started. According to the first feature, when two of these robots come close to each other,
The individual coordinate systems of both robots are integrated. As a result, a similar robot group consisting of two robots is generated.
According to the second feature, the number of robots included in this group of similar robots sequentially increases, and finally the group of robots becomes one group of similar robots, that is, all individual coordinate systems are integrated. If all the individual coordinate systems are integrated, the robot's communication function allows the robots to communicate each individual map, or humans collect each individual map and synthesize them to create a map of the entire environment. To be done.

[0013]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram showing an example of a mobile robot.

This robot includes a television camera 1 which is a sensor, a supporting base 2 thereof, a computer 3 and a wireless communication device 4.
A wheel 5, a drive mechanism 6 for the wheel 5, a frame 7,
It consists of signal cables 8, 9 and 10. The TV camera 1 is installed on the support base 2 so as to be oriented in an arbitrary direction. The wireless communication device 4 communicates information with other robots. The wheels 5 are fixed to the frame 7, and the drive mechanism 6 moves the robot in an arbitrary direction instructed by the computer 3. The signal cable 8 is a signal path for transmitting a shooting instruction of the computer 3 to the television camera 1, and transmitting the image signal generated by the television camera 1 and the rotation direction and angle of the television camera 1 to the computer 3. Signal cable 9 is computer 3
Is a signal path between the wireless communication device 4 and the wireless communication device 4. The signal cable 10 is a signal path for transmitting the movement information output by the computer 3 to the drive mechanism 6. The computer 3 includes a storage device and stores a program that realizes the operation of the robot, and the television camera 1, the wireless communication device 4, and the drive mechanism 6 are stored by the program.
To control.

FIG. 2 shows a case where a robot group consisting of two robots A and B having the structure shown in FIG. 1 moves in an environment E where various objects exist to create an environment map.
It is the schematic diagram which looked at the mode which integrated the individual coordinate systems _Axy and _Bxy from the upper side. For the sake of simplicity, descriptions of objects existing in the environment E other than the object F are omitted.

The robots A and B are respectively located at points P _A and P _B which are initially distant from each other in the environment E, and set individual coordinate systems A _xy and B _xy at the respective points P _A and P _B. . Next, the robots A and B move in the environment E while recognizing their positions on the individual coordinate systems A _xy and B _xy using the dead reckoning described above, and at the same time, they are present in the surroundings. The object is observed by the TV camera 1 to create an individual map.

The robots A and B move in the environment E along the loci h and i while performing the above operations, reach the points P _A ′ and P _B ′, and approach each other. The recognition that both robots have approached each other is possible by using a measurement function that the robot measures the positions of other robots that are in close proximity. The measurement function can be realized by a method in which one robot uses two TV cameras to stereoscopically view the other robot, for example.

The robot A measures the position of the robot B using the above function and obtains the vector c representing the relative position to itself. The robot B transmits to the robot A a vector b representing its own position on the individual coordinate system B _xy . Robot A adds the vector a representing the self position on the inverse vector -b and individual coordinate system A _xy of vector c and vector b, representing the relative position with respect to the individual coordinate system A _xy of the individual coordinate system B _xy Get the vector d. Further, the robot A takes a difference between the vector a and the obtained vector d to obtain a vector e representing the position of itself on the individual coordinate system B _xy.
Then, the vector a representing the position of the self on the individual coordinate system A _xy is replaced with the vector e.

Further, the robot A has the individual coordinate system A by the time when the robots A and B arrive at positions close to each other.
_The individual map created on _xy is converted into a map based on the individual coordinate system B _xy . For example, if the position of the object F is the individual coordinate system A _xy
If represented by the vector f above, the individual coordinate system B can be obtained by calculating the difference between the vector f and the vector d.
_An object F based on the individual coordinate system A _xy is obtained by _finding a vector g on _xy and replacing the vector f with the vector g.
The individual maps of the individual coordinate system B _xy which is a common individual coordinate system
Convert to individual map based on.

By the above operation, the robot A converts its own individual coordinate system A _xy into the same as the robot B's individual coordinate system B _xy, and at the same time, its own individual map B _xy.
Replaced with a map based on. That is, the two robots A and B that create the environment map of the environment E have integrated their individual coordinate systems.

The robot A transmits the vector c and the vector a to the robot B, and the robot B adds the inverse vector −a of the vector c and the vector a and the vector b,
A vector d'representing the relative position of the individual coordinate system A _xy with respect to the individual coordinate system B _xy is obtained, and the position of the self on the individual coordinate system A _xy is represented by taking the difference between the vector b and the obtained vector d '. Find the vector and use it as the individual coordinate system B _xy
It may be replaced with the vector b representing the self position above. In this case, the robot B will convert the individual map created on the individual coordinate system B _xy into a map based on the individual coordinate system A _xy . Figure 3 is for creating an environment map of environment E 4
In the process in which the robot group consisting of the robots A, B, C, D moves along the trajectories j, k, l, m, their individual coordinate systems A _xy , B _xy , C _xy , D _xy are set. It is the schematic diagram which looked at the state of integrating from the upper side. For simplicity, the description of the objects existing in the environment E is omitted.

The four robots A, B, C and D are initially
They are located at places far apart from each other in the environment E, and individual coordinate systems A _xy , B _xy , C _xy and D _xy are set at the respective places. Next, these four robots A, B, C, D
Each individual coordinate system A _xy , B using dead reckoning
_The television camera 1 moves in the environment E while recognizing its own position on _xy , C _xy , and D _xy , and at the same time, sees the surrounding objects
Observe and create an individual map.

The robots A and B move in the environment E along the trajectories j and k, respectively, while performing the above operations, and come close to each other near the point P ₁ . At this point, both robots A and B perform the operations described with reference to FIG. 2, and robot B integrates the individual coordinate system B _xy into the individual coordinate system A _xy . As a result, the same group of robots {A, B} having the individual coordinate system A _xy as a common individual coordinate system is generated. On the other hand, when the robots C and D move in the environment E along the trajectories 1 and m, respectively, and approach each other near the point P ₂ , the robot D at the point P ₁ receives its own individual coordinate system in the same manner as the robot B at the point P ₁ . Integrate D _xy into the individual coordinate system C _xy . As a result, the same group of robots {C, D} having the individual coordinate system C _xy as a common individual coordinate system is generated.

Next, the robots A and D further move along the trajectories j and m, respectively, and approach each other near the point P ₃ . At this point, the robot D integrates the individual coordinate system C _xy into the individual coordinate system A _xy of the robot A. At this time, since the two robots A and D already belong to the robot groups {A, B} and {C, D}, respectively, the robot C belonging to the latter robot group performs the operation shown in FIG. Convert the coordinate system. That is,
In the robot group {C, D}, the robot D has an individual coordinate system C
_{Since xy} is converted into the individual coordinate system A _xy , the robot C belonging to the same robot group also _{changes the} individual coordinate system C _xy into the individual coordinate system A _xy.
By converting to _xy , the individual coordinate system in the robot group is kept the same. On the other hand, regarding the robot group {A, B},
It is not necessary to transform the individual coordinate system for any robot.

By the above operation, a group of similar robots {A, B, C, D} consisting of four robots A, B, C, D for creating an environment map is generated. As a result, each robot A,
The individual coordinate systems A _xy , B _xy , C _xy , and D _{xy of} B, C, and D are all integrated into an individual coordinate system A _xy , which is the only common individual coordinate system. After that, each of the robots A, B, C, and D synthesizes the created individual maps by transmitting them to each other to generate a map of the entire environment. The operation of converting the vector of the object based on each individual coordinate system into the vector on the common individual coordinate system may be performed every time the conversion of the individual coordinate system is performed, or all the individual coordinate systems are unique. It may be performed after being integrated into a common individual coordinate system (in this case, the individual coordinate system A _xy ).

[0027]

As described above, according to the present invention, in the coordinate system integration step, the individual coordinate systems of the robots having different individual coordinate systems are sequentially integrated to form the only common individual coordinate system. There is an effect that it is possible to create a map of the entire environment without losing the advantages of creating an environment map using a plurality of robots.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a structure of an example of a mobile robot used in the present invention.

[Fig. 2] Two robots A and B that create an environmental map
It is the schematic diagram which looked at the mode which integrated the individual coordinate systems _Axy and _Bxy from the upper side.

[Fig. 3] Four robots A, B, which create an environmental map
It is the schematic diagram which looked at the state which C and D integrated the individual coordinate system _Axy , _Bxy , _Cxy , _Dxy from the upper side.

[Explanation of symbols]

A, B, C, D Robot E Environment F Object P _A , P _A ', P _B , P _B ', P ₁ , P ₂ , P ₃ points A _xy , B _xy , C _xy , D _xy Individual coordinate system a , B, c, d, e, f, g vector h, i, j, k, l, m robot trajectory

Claims (1)

[Claims] 1. A plurality of robots each having a direction-selectable moving ability and a sensor for detecting a surrounding situation and capable of communicating with each other move individually and simultaneously in an environment where various objects are present. Then, each robot creates an individual map in the vicinity of the robot based on the individual coordinate system set by itself, and combines the created individual maps to create a map of the entire environment. A method for creating an environment map, wherein when a sensor mounted on a first robot detects the approach of a second robot having a different individual coordinate system,
The first robot measures the position of the second robot with a sensor, obtains a vector c representing the relative position with respect to itself on the first coordinate system, which is the individual coordinate system of itself, and Then, the first robot transmits the vector b representing its own position on the second coordinate system, which is its own individual coordinate system, and the first robot makes the inverse vector −b of the vector c and the vector b.
And a vector a representing its own position on the first coordinate system are added to obtain a vector d representing the relative position of the second coordinate system with respect to the first coordinate system, or The vector c and the vector a are transmitted to the robot of the second coordinate system, and the second robot adds the inverse vector −a and the vector b of the vector c and the vector a to obtain the second coordinate system of the first coordinate system. The robot has a coordinate system integration step of obtaining a vector d'representing a relative position with respect to one of the individual coordinate systems as a common individual coordinate system and integrating the other individual coordinate system with it. Recognizing the position of an object on its own individual coordinate system, creating the individual map, and when two robots having different individual coordinate systems approach each other, the coordinate system integration step is executed to execute one of the individual coordinate systems. If integrated system to the other individual coordinate systems, there robot to another having the same individual coordinate system as one of the individual coordinate systems the,
Repeating the coordinate system integration step to integrate the individual coordinate system of the robot with the other individual coordinate system until all robots have a single common individual coordinate system. From the vector representing the position of the object on the coordinate system, the position of the object is represented by subtracting the vector d or d ′ obtained in the coordinate system integration step, which represents the relative position of the common individual coordinate system with respect to its own individual coordinate system. By converting the vector to a vector on a common individual coordinate system, the process of converting the own individual map to an individual map on a common individual coordinate system is performed in the coordinate system integration step, or at the only common individual coordinate system. After that, a method for creating an environmental map using multiple mobile robots that integrates individual maps on a single common individual coordinate system.