The present application claims priority from Japanese application JP2007-261517 filed on Oct. 5, 2007, the content of which is hereby incorporated by reference into this application.
(1) Field of the Invention
The present invention relates to a mobile robot system, and more particularly to a mobile robot system having a function of generating and updating a map.
(2) Description of Related Art
There has been proposed a method structured such that a mobile robot measures a peripheral state, and simultaneously generates a map while estimating a self position on the basis of the data. Since this method is a technique called as a simultaneous localization and mapping (SLAM), and the robot can estimate the self position while generating the map, even in the case that the robot is set under an environment having no map information, this method has a feature of moving in a self-sustaining manner.
For example, in patent document 1 (JP-A-2004-276168), there is shown a method of generating a novel map information by simultaneously estimating a map information expressed by a relative posture between objects and a posture of the robot by a mobile sensor and a recognizing means of the mobile robot. Further, in patent document 2 (JP-A-2005-332204), there is described a self position detecting means such as a global positioning system (GPS) or the like, an object detecting means detecting a distance and a direction with respect to a peripheral object, and a mobile control apparatus provided with a function of generating an environmental map in a moving direction on the basis of the detected data. Further, in patent document 3 (JP-A-2007-94743), there is shown a structure in which a map data generating portion and a position estimating portion are arranged in a self-sustaining mobile type robot or a server apparatus.
The robot systems shown by these known arts can be divided into two cases in accordance with an arranged method of the map generating portion generating the map and the self position estimating portion estimating the self position of the robot. One method corresponds to a case that the map generating portion and the self position estimating portion are incorporated in the robot, and the other method corresponds to a case that they are incorporated in a superior controller (a server apparatus) controlling a motion of the robot. In this case, in the case of the robot system aiming at the map generation itself, since it is not necessary that the robot operates in a self-sustaining manner, a vehicle operated or pushed by a human being is called as the robot of the present invention.
In the former case, there is a problem that a memory apparatus storing the map is enlarged in size as well as a computing load of the robot controller incorporated in the robot becomes very large. Particularly, in the system in which a plurality of robots simultaneously operate, in the case of mutually utilizing the maps generated by the respective robots, it is necessary to regenerate a wide map while outputting the map information of each of the robots to the superior controller, and securing a consistency of the maps by the superior controller. Accordingly, it is necessary to communicate enormous data so as to carry out a high-speed computing process by the superior controller.
Further, in the latter case, since the map is generated while transmitting the peripheral environmental information (an image, an obstacle detection, a sensor information of the moving mechanism and the like) obtained by the robot to the superior controller, and estimating the position, it takes a long time to transmit and receive between the superior controller and the robot in the case of controlling so as to move the robot on the basis of the peripheral environmental information, and there is a problem that it is impossible to carry out a robot traveling control having a high-speed response. Further, in the case of operating a plurality of robots in accordance with this method, there is a problem that the superior controller requires a high-speed and high-performance computing process, for computing the robot traveling control.
The present invention is made by taking the problem mentioned above into consideration, and an object of the present invention is to provide a robot system in which a superior controller is comparatively inexpensive even in the case of driving a plurality of robots, as well as reducing a computing load while securing a high response performance of the robot.
In order to achieve the object mentioned above, the following correspondence is intended.
There is provided a robot system constructed by a controller having a map data and a mobile robot, wherein the robot includes a distance sensor measuring a plurality of distances with respect to a peripheral object, and an identifying apparatus identifying a position and an angle of the robot by collating with the map data, and the controller includes a map generating apparatus generating or updating the map data on the basis of the position and the angle of the robot, and the measured distance with respect to the object.
Accordingly, it is possible to achieve a comparatively inexpensive robot system which can reduce a computing load of the controller and the robot. Particularly, even in the case of the robot system constructed by a plurality of robots, it is possible to achieve the system without enhancing a performance of a superior controller very much.
In accordance with the present invention, there can be provided a robot system constructed by a controller having a map data and a plurality of mobile robots, wherein the robot identifies a position and an angle of the robot by measuring a plurality of distances with respect to a peripheral object, and collating the map data input from the controller, and the controller generates or updates the map data on the basis of the distance with respect the object measured by the plurality of robots and the position and angle.
Further, in accordance with the present invention, there is provided a robot system constructed by a controller having a map data and a mobile robot, wherein the robot includes a distance sensor measuring a plurality of distances with respect to a peripheral object, a data selecting apparatus selecting a region map data near the robot in the map data, and an identifying apparatus identifying a position and an angle of the robot by collating the region map with the distance, and the controller includes a map generating apparatus generating or updating the map data on the basis of the position and the angle of the robot, and the measured distance with respect to the object.
Further, in accordance with the present invention, there is provided a robot system constructed by a controller having a map data and a mobile robot, wherein the robot includes a distance sensor measuring a plurality of distances with respect to a peripheral object, a memory apparatus storing a region map data near the robot in the map data, and an identifying apparatus identifying a position and an angle of the robot by collating the region map with the distance, and the controller includes a map generating apparatus generating or updating the map data on the basis of the position and the angle of the robot, and the measured distance with respect to the object.
In the robot system in accordance with the present invention, it is preferable that the distance sensor is constituted by a laser distance meter.
In the robot system in accordance with the present invention, it is preferable that the robot moves in a self-sustaining manner on the basis of the position and the angle of the robot and a motion instruction from the controller, after identifying the position and the angle of the robot.
In the robot system in accordance with the present invention, it is preferable that the plurality of robots mutually identify the positions of the robots.
In the robot system in accordance with the present invention, it is preferable that the region map data is changed on the basis of the identified position of the robot.
In the robot system in accordance with the present invention, it is preferable that the region map data is changed at a time when the position of the robot is moved at a predetermined distance or more from the position of the robot at a time of selecting or storing the region map data.
Further, there is provided a robot system constructed by a controller having a map data and a mobile robot, wherein the robot includes a distance sensor measuring a plurality of distances with respect to a peripheral object, a data selecting apparatus selecting a region map data near the robot in the map data, and an identifying apparatus identifying a position and an angle of the robot by collating the region map data with the distance. Therefore, there can be provided the robot system in which the robot is activated in a further wide range of region, and it is possible to achieve the object mentioned above.
In accordance with the present invention, since it is possible to reduce a computing load of a robot and a controller, there can be obtained a comparatively inexpensive robot system controlling a robot having a high response.
Other objects, features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings.
A description will be given of an embodiment in accordance with the present invention with reference to
In this case, a position of the robot 2 in an absolute coordinate system (x-y stationary coordinate system) is set to (xr, yr), and an angle of the robot 2 is expressed by θr. Further, the robot position (xr, yr) and the angle θr are called as a posture of the robot 2 together.
First, a description will be given of an operation relating to the traveling control of the robot 2 with reference to
In the traveling control command portion 3 of the controller 1, if a command is given from a human being, or a command or the like is given from a superior robot operation control system which is not mentioned, the traveling control command portion 3 moves the robot 2 to the starting point 41 on the basis of the robot position (xr, yr) obtained from the commands and the posture of the robot 2, thereafter plans a traveling path of the robot to the reaching point 42, and outputs a path shown by a broken line such as
Next, a description will be given of the distance sensor 9 in
In this case, a description will be given of a processing content in the identifying apparatus 10 in
In this case, a description will be given of a computing method of the identifying apparatus 10 determining the actual posture (xr, yr, θr) of the robot 2 on the basis of the initial posture (xr0, yr0, θr0) with reference to
When each of the values of the initial posture (xr0, yr0, θr0) simultaneously comes into line with the actual posture (xr, yr, θr), the map approximately comes into line with the data of the distance d, as shown in
A step 101 inputs the estimated posture of the robot, that is, the initial posture (xr0, yr0, θr0). A step 102 calculates an initial value (xrc, yrc, θrc) for searching, with regard to three parameters, as shown in
In the case that the summation Ec is smaller than the summation E, as a result of comparing the summation E with the summation Ec in a step 105, a process in a step 106 is carried out. In the case that the summation Ec is equal to or more than the summation E, the step directly jumps to a step 107. The process of the step 106 sets the summation Ec, the positions xrc and yrc, and the angle θrc respectively to the summation E, the positions xr and yr, and the angle θr. The process of the step 106 means storing the positions xrc and yrc and the angle θrc of the smallest summation Ec in the summation Ec calculated in the step 104 as the positions xr and yr and the angle θr. After the process of the step 106 is finished, the step jumps to the step 107.
The calculation in the step 107 resets the position xrc as the position xrc by adding only an x-axis calculation width Δx. It is desired to set the x-axis calculation width Δx to a small value which is considered from a precision and a calculated amount of the posture (xr, yr, θr) obtained by identifying. The same matter is applied to a y-axis calculation width Δy, and an angle calculation width Δθ.
A step 108 determines whether or not the position xrc reaches xr0+W/2, and repeats the processes from the step 103 to the step 107 if the position xrc is equal to or less than xr0+W/2. The processes up to here are provided for carrying out the calculation of the summation Ec per the x-axis calculation width Δx from xr0−W/2 to xr0+W/2 of the position xrc, in a state of setting the position yrc and the angle θrc constant, and determining the minimum value in the range. In the case that the step 108 determines that the position xrc gets over xr0+W/2, it means that the position xrc is out of the distance searching region. Accordingly, the step jumps to a step 109, and replaces the position yrc to the position yrc obtained by adding only the y-axis calculation width Δy to the initial value xr0−W/2 of the position xrc. A step 110 determines whether or not the position yrc reaches yr0+W/2 in the same manner as the step 108, and repeats the processes from the step 103 to the step 109 if the position yrc is equal to or less than yr0+W/2. As a result, it is possible to determine the minimum value in a whole region of the distance searching region in the x-axis and y-axis directions by setting θrc as a fixed value, in the summation E. Accordingly, it is possible to obtain the posture (xr, yr, θr) of the robot in which the summation in the range becomes minimum.
In the case that the step 110 determines that the position yrc gets over yr0+W/2, a process shown in a step 111 in
A description will be given of the computing method by using a flow chart in
In accordance with the process mentioned above, the robot 2 identifies the posture of the robot 2 on the basis of the collected distance data, and the controller 1 always adds and updates the map. Accordingly, since the map generation is separated from the posture identifying process in which a high-speed computing process time is necessary, it is possible to lighten the computing process carried out by the robot 2, and it is possible to make the robot inexpensive.
Next, a description will be given of a characteristic map generating apparatus 27 in the present embodiment with reference to
In this case, a difference between the conventional system and the present embodiment is put together. First, a description will be given of a case of a system of carrying out all the identification of the posture of the robot and the map generation by the controller 1, as one of the conventional system. In this case, there is a problem that the computation is enormous for identifying the postures of a lot of robots, and it takes a long time to obtain the result of computation. In other words, in the feedback control of the robot on the basis of the posture identifying result, it is impossible to achieve a high-speed response. Further, as the other case of the conventional system, in the system in which the robot carries out the posture identification and the map generation, there exist a plurality of maps generated only by the information collected by the robots, and there is a problem that it is impossible to make good use of the latest information obtained by the other robots. On the contrary, in accordance with the embodiment in
The step 309 collates the postures of all the robots input to the map generating apparatus in
Further, as shown in
The traveling control command portion 31 determines the traveling command in accordance with the same method as the traveling control command portion 3 in
Further, a characteristic point of the present invention is the data input to and output from the map data memory portion 30. The map generating apparatus 5 determines what zone the robot 2 exists, on the basis of the posture of the robot 2, and outputs a zone selecting command to the map data memory portion 30. On the basis of the zone selecting command, the zone map in which the robot exists is output to the identifying apparatus 10 of the robot 2 from the map data memory portion 30. The identifying apparatus 10 is the same as the embodiment in
In the case that the robot moves outside the set zone, there is a characteristic that the map can be automatically rewritten to the zone map required by the robot 2, by changing the zone selecting command. Accordingly, since it is possible to identify the posture of the robot, generate and update the map without enlarging the memory apparatus required by the map of the robot, in the robot system moving around the wide range or region, by using the present embodiment, there is obtained an advantage that it is possible to comparatively inexpensively provide the robot system moving in the wide range of operating region such as a factory, a physical distribution center or the like.
The above is the embodiment applied to the robot system operated in the predetermined operating region such as the factory, the physical distribution center or the like, however, the present invention can be applied to a robot system operating in a building or a hospital. With regard to the system operated by one robot and the system operated by a plurality of robots, the description is given of the method of controlling the robot in accordance with the different control methods as the embodiment, however, it is effective to employ a method obtained by combining these methods. Further, as is mentioned above, since it is not necessary for the robot to operate in the self-sustaining manner in the case of the robot system aiming at the map generation, the vehicle operated or pushed by the human being correspond to the robot in accordance with the present invention, and the present invention can be applied thereto. Therefore, the present invention is not limited to the method mentioned in the present embodiment, but the present invention can be widely applied to the case using a plurality of combinations together.
It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modifications may be made without departing from the spirit of the invention and the scope of the appended claims.
Number | Date | Country | Kind |
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2007-261517 | Oct 2007 | JP | national |