JP2014073550A - Path searching method, path searching device, robot control device, robot, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To search a high quality path at a high speed.SOLUTION: A path for moving from an initial attitude to a target attitude is searched by performing RRT(Rapidly-Exploring Random Trees) in a search range including the initial attitude and the target attitude of a movable part 11, and performing a road map method in a range including a path obtained by the RRT.

Description

  The present invention relates to a route search method, a route search device, a robot control device, a robot, and a program.

  In Patent Document 1, the trajectory from the current position to the target position is acquired by RRT (Rapidly-exploring Random Tree), and by executing a dynamic simulation using the position on the trajectory discovered by RRT as an initial condition, A trajectory planning apparatus that generates a trajectory that satisfies the above requirements is disclosed.

JP 2008-55681 A

  RRT can calculate a route at high speed without the need to create a road map, but compared to other methods such as a road map method, the route to be discovered is rough, that is, a route with a lot of useless movement. End up.

  Although the invention described in Patent Document 1 can solve the problem of RRT, an increase in calculation time is inevitable because dynamic simulation is used. Specifically, it takes time because a potential field must be generated for each processing. In addition, there is a problem that processing does not proceed when it falls into an extreme value.

  Therefore, an object of the present invention is to provide a route search method, a route search device, a robot control device, a robot, and a program that can search for a high-quality route at high speed.

  A first aspect for solving the above-described problem is a route search method for searching for a route by which a movable part of a robot moves from an initial posture to a target posture, and within a search range including the initial posture and the target posture. A first step of generating a first movement path of the robot by executing RRT (Rapidly-Exploring Random Trees) and executing a road map method within a first range including the first movement path And a second step of generating a second movement route different from the first movement route, and a third step of outputting the second movement route as a searched route. It is characterized by.

  According to the first aspect, a route is searched by RRT, and a route is searched by a road map method (probabilistic road map method) using the result. Thereby, it is possible to search for a high-quality route at high speed.

  Here, in the first step, the first path connecting a plurality of first points is generated, and in the second step, a point between the first point and the first point is generated. May be set as the second point, a plurality of points may be selected from the second points, and the selected points may be connected to generate the second movement path. As a result, a route superior to the route searched by RRT can be reliably searched.

  Here, the second step is performed between the second step and the third step, and is a second step that is narrower than the first range and includes a part of the second movement path. A fourth step of generating a third movement path different from the second movement path by executing a road map method within a range of the second movement path, wherein the second movement Instead of the route, the third movement route may be output. This makes it possible to search for a better route without increasing the calculation time as much as possible.

  Here, in the fourth step, the second range may be set so as to include at least one of the first points. Thereby, a good route can be surely found by the road map method.

  Here, in the fourth step, the third movement is performed by setting a plurality of the second ranges at different positions and executing a road map method inside each of the plurality of second ranges set. A route may be generated. This makes it possible to search for a better route without increasing the calculation time as much as possible.

  Here, a fifth step performed between the fourth step and the third step, which is narrower than the first range, includes a part of the second movement path, and A fifth step of generating a fourth movement route different from the third movement route by executing a road map method within a third range different from the second range; and the fifth step And a sixth step performed between the third step and the third step, which evaluates which of the third route and the fourth route is a better route; In the third step, instead of the second movement route, a route evaluated as a better route in the sixth step may be output. This makes it possible to search for a better route without increasing the calculation time as much as possible.

  According to a second aspect of the present invention, there is provided a route search device that searches for a route along which the movable portion of the robot moves from the initial posture to the target posture. When the initial posture and the target posture are included, RRT ( A first movement path generation unit that generates a first movement path of the robot by executing Rapidly-Expanding Random Trees, and a road map method is executed within a first range including the first movement path. And a second movement route generation unit that generates a second movement route that is different from the first movement route, and an output unit that outputs the second movement route as a searched route. It is characterized by. Thereby, it is possible to search for a high-quality route at high speed.

  A third aspect of the present invention is a robot control apparatus for controlling a robot having a movable part, and executes RRT (Rapidly-Expanding Random Trees) within a search range including an initial posture and a target posture of the movable part. The first movement path generation means for generating the first movement path of the robot by performing the road map method within a first range including the first movement path, thereby performing the first movement And a second movement path generation unit that generates a second movement path different from the path, and an output unit that outputs the second movement path to the robot as a searched path. Thereby, it is possible to search for a high-quality route at high speed.

  According to a fourth aspect of the present invention, there is provided a robot having a movable part formed so as to be movable from an initial posture to a target posture, and an RRT (Rapidly-Exploring Random) within a search range including the initial posture and the target posture. By executing a road map method within a first range including the first movement path, a first movement path generation means for generating a first movement path of the robot by executing (Trees) A second movement path generation unit that generates a second movement path that is different from the first movement path; and a control unit that controls the movement unit as a route searched for the second movement path. It is characterized by. Thereby, it is possible to search for a high-quality route at high speed.

  According to a fifth aspect of the present invention, there is provided a program for searching for a path along which a moving part of a robot moves from an initial posture to a target posture, and within a search range including the initial posture and the target posture, RRT (Rapidly-Exploring). A first step of generating a first movement path of the robot by executing Random Trees; and a road map method within a first range including the first movement path, A second step of generating a second movement route different from the one of the movement routes, and a third step of outputting the second movement route as a searched route. And Thereby, it is possible to search for a high-quality route at high speed.

It is a figure which shows an example of a structure of the robot system 1 in one Embodiment of this invention. 2 is a block diagram illustrating an example of a functional configuration of a robot system 1. FIG. 2 is a diagram illustrating a hardware configuration of a control unit 30. FIG. It is a flowchart which shows the flow of a route search process (1st form). It is a figure explaining the process of step S100. It is a figure explaining the process of step S102. It is a figure explaining the process of step S104. It is a figure explaining the process of step S104. It is a flowchart which shows the flow of a route search process (2nd form). It is a figure explaining the process of step S110. It is a figure explaining the process of step S112. It is a figure explaining the process which can be added to a route search process. It is a figure explaining the modification of step S110. It is a flowchart which shows the flow of a route search process (3rd form). It is a figure explaining the process of step S114.

  An embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a system configuration diagram showing an example of a configuration of a robot system 1 according to an embodiment of the present invention. The robot system 1 in this embodiment mainly includes a robot 10, a photographing unit 20, and a control unit 30.

  The robot 10 is an arm type robot having an arm portion including a plurality of joints (joints) 12 and a plurality of links 13. A hand 14 (so-called end effector) capable of gripping a target object (work) or performing a predetermined operation on the target object by holding a tool is provided at the tip of the arm portion. Hereinafter, the arm part and the hand 14 of the robot 10 are referred to as a movable part 11.

  The joint 12 and the hand 14 are provided with an actuator (not shown) for operating them. The actuator includes, for example, a servo motor and an encoder. The encoder value output from the encoder is used for feedback control of the robot 10 by the control unit 30.

  Note that the configuration of the robot 10 is not limited to the above-described configuration because the main configuration has been described in describing the features of the present embodiment. This does not exclude the configuration of a general gripping robot. For example, although a 6-axis arm is shown in FIG. 1, the number of axes (number of joints) may be further increased or decreased. The number of links may be increased or decreased. In addition, the shape, size, arrangement, structure, and the like of various members such as the arm, hand, link, and joint may be appropriately changed. The end effector is not limited to the hand 14. The robot may be a so-called double-arm robot having two arms. Furthermore, the present invention can also be applied to any type of robot, for example, a self-propelled robot, as long as it can create an arrangement space.

  The photographing unit 20 is a unit that photographs the vicinity of the work area of the movable unit 11 and generates image data. The imaging unit 20 includes, for example, a camera and is provided on a work table, ceiling, wall, or the like. In FIG. 1, the photographing unit 20 is provided at the upper end of the robot 10. As the photographing unit 20, a visible light camera, an infrared camera, or the like can be employed.

  The control unit 30 performs processing for controlling the entire robot 10. The control unit 30 may be installed at a location away from the main body of the robot 10 or may be built in the robot 10. When the control unit 30 is installed at a location away from the main body of the robot 10, the control unit 30 is connected to the robot 10 by wire or wirelessly. Further, the photographing unit 20 may be connected to the robot 10 instead of the control unit 30 or may be built in the robot 10.

  Next, a functional configuration example of the robot system 1 will be described. FIG. 2 is a functional block diagram of the robot system 1.

  The robot 10 includes an operation control unit 101 that controls the movable unit 11 based on an encoder value of an actuator, a sensor value of a sensor, and the like.

  The control unit 30 mainly includes an RRT route discovery unit 301, a collision detection unit 302, and a road map method execution unit 303. The control unit 30 is connected to the robot 10 so as to be communicable by wire or wireless.

  The RRT route discovery unit 301 searches for a route using the RRT. Specifically, after setting the initial position on the search space, the RRT path finding unit 301 arranges a random sample position in the search space and searches for the nearest position from the initial position toward the sample position, Connect the initial position and the nearest position to the tree. The RRT route finding unit 301 generates a tree that covers the search space by repeating the processing. The RRT route finding unit 301 searches for a route between the initial posture and the target posture based on the tree. Since RRT is a well-known technique, detailed description thereof is omitted.

  The collision detection unit 302 detects whether or not the movable unit 11 collides with an obstacle when the RRT route discovery unit 301 and the road map method execution unit 303 search for a route. The detection result is output to the RRT route finding unit and the road map method executing unit. Since the method for detecting whether or not the movable part 11 collides with an obstacle is already known, the description thereof is omitted.

  The road map method execution unit 303 sets an arbitrary range and searches for a route by executing the road map method (probabilistic road map method) within the set range. The road map method execution unit 303 includes a road map creation unit 303A and a shortest path detection unit 303B.

  The road map creation unit 303A sets an arbitrary range, randomly selects several postures within the set range, and connects them with branches if they can move to nearby postures. Random walk from postures in areas with many obstacles to expand the roadmap. Since the method for generating the road map is a known method, detailed description thereof is omitted. A method for setting an arbitrary range will be described in detail later.

  The shortest path detection unit 303B obtains the shortest path in the road map generated by the road map creation unit 303A using a known method such as an A * (A star) algorithm or a Dijkstra method. Since the A * algorithm, Dijkstra method, etc. are already known methods, detailed description thereof is omitted.

  FIG. 3 is a block diagram illustrating an example of a schematic configuration of the control unit 30. As shown in the figure, the control unit 30 constituted by, for example, a computer is composed of a CPU (Central Processing Unit) 31 that is an arithmetic device, a RAM (Random Access Memory) that is a volatile storage device, and a nonvolatile storage device. A memory 32 composed of a certain ROM (Read only Memory), an external storage device 33, a communication device 34 for communicating with an external device such as the robot 10, an input device 35 such as a mouse and a keyboard, and an output device such as a display 36, a read / write device 37 such as a CD drive or a DVD drive, and an interface (I / F) 38 for connecting the control unit 30 to other units.

  Each functional unit described above is realized, for example, when the CPU 31 reads a predetermined program stored in the memory 32 and executes the program. The predetermined program may be installed in the memory 32 in advance, or may be downloaded from the network via the communication device 34 and installed or updated.

  The configuration of the robot system 1 described above is not limited to the above-described configuration because the main configuration has been described in describing the features of the present embodiment. For example, the robot 10 may include the imaging unit 20 and the control unit 30. Further, the configuration of a general robot system is not excluded.

  Next, a characteristic process of the robot system 1 having the above configuration in the present embodiment will be described.

<Route search process (first form)>
FIG. 4 is a flowchart showing the flow of the route search process (first form). FIGS. 5-8 is a figure explaining a route search process (1st form). This process is started, for example, when a search start instruction is input via a button or the like (not shown).

  In FIGS. 5 to 8, the node is shown as a position on a plane for the sake of simplicity, but this point actually indicates the attitude of the movable portion 11. In the present embodiment, since the movable part 11 has 6 axes (6 degrees of freedom), each node is represented by a 6-dimensional parameter. The parameters include not only the position of the joint 12 and the hand 14 but also the angle, posture, and the like.

  The RRT path finding unit 301 acquires an image of an area including the movement start position and the target position of the movable unit 11 from the imaging unit 20, and sets an operable range on the acquired image (step S100). Specifically, as illustrated in FIG. 5, the RRT route finding unit 301 sets the smallest rectangular region including the movement start position S of the movable unit 11 and the target position G as an operable range. In FIG. 5, the inoperable range is a region where an obstacle or the like exists, for example, and indicates a region where the movable part 11 should not interfere.

  The operable range is not limited to a rectangle, and may be any form as long as it includes the movement start position S and the target position G. Further, the size of the operable range is not limited to the smallest range including the movement start position S and the target position G. However, in order to find the route efficiently, it is desirable to set the operable range within the smallest range including the movement start position S and the target position G.

  The RRT route discovery unit 301 executes RRT within the operable range and searches for a route (step S102). Step S102 corresponds to the first step of the present invention. In step S102, the collision detection unit 302 determines whether or not the movable unit 11 does not interfere with the inoperable range at each stage of executing RRT, and outputs the determination result to the RRT route discovery unit 301. Based on the result output from the collision detection unit 302, the RRT route discovery unit 301 searches for a route in which the movable unit 11 does not interfere with the inoperable range.

  FIG. 6 shows the result of executing RRT within the operable range shown in FIG. The white circle in FIG. 6 is the node N1 set by the RRT, and the path connecting the nodes N1 is a route searched by the RRT. In FIG. 6, nodes not related to the route are omitted. The route searched by RRT corresponds to the first movement route of the present invention, and the node N1 set by RRT corresponds to the first point of the present invention.

  The RRT route discovery unit 301 outputs the information on the route searched in step S102 to the road map method execution unit 303. Based on the route output from the RRT route finding unit 301, the road map creating unit 303A sets a range A, which is a range for executing the road map method, on the image acquired in step S100 (step S104). Range A corresponds to the first range of the present invention.

  The range A is a range in which the operation movable range is limited by the range of the maximum value and the minimum value of the parameters in the route discovered in step S102. In other words, the range A is the smallest rectangular area including the movement start position S, the target position G, and all the nodes of the route searched in step S102. As a result, it is possible to remove an area that is not considered to be used for the route. In the example shown in FIG. 6, the range A is the same range as the operable range. The range A is not limited to a rectangle, and may include the movement start position S, the target position G, and all the nodes on the route searched in step S102.

  Here, the range A is desirably as small as possible. This is because the road map method takes time in proportion to the square of the number of nodes, and therefore it is desired to reduce the number of nodes, that is, to narrow the range in which the road map method is performed.

  The road map method execution unit 303 executes the road map method within the range A set in step S104 (step S106). Step S106 corresponds to the second step of the present invention. Hereinafter, the process of step S106 will be described.

  The road map creation unit 303A sets a node within the range A. FIG. 7 is a diagram illustrating a state in which the nodes within the range A are set. The black circle in FIG. 7 is the node N1 of the route searched in step S102.

  As shown in FIG. 7, the road map creation unit 303A, as a part of the nodes used for road map creation, the node N1 (see the black circle in FIG. 7) of the route searched in step S102 and the intermediate point N2 ( The shaded circles in FIG. 7 are used as nodes. The midpoint N2 of the node corresponds to the second point of the present invention. This is because using the intermediate point N2 of the node N1 increases the possibility of a shortcut to the route. The intermediate point of the node is not limited to the middle point between the node and may be a point divided into three or a point divided into ten. Further, the number of intermediate points of the node is not limited to one, and may be two or ten. Furthermore, the road map creation unit 303A also sets a node N3 that is not related to the nodes N1 and N2.

  In the present embodiment, since the node N1 of the route searched for by RRT is reused, a route with lower quality than the route searched for by RRT is not found at least. The node setting may be input by the user. This is made possible by the road map method execution unit 303 outputting an image as shown in FIG. 7 to the output device 36 and inputting it via the input device 35 by the user.

  The shortest path detection unit 303B searches for the shortest distance from a number of nodes set within the range A and determines it as a path searched by the road map method. The route searched by this road map method corresponds to the second movement route of the present invention. FIG. 8 shows a route determined using the node shown in FIG. It can be seen that the route shown in FIG. 8 is improved over the route searched by the RRT shown in FIG.

  The road map method execution unit 303 outputs the route searched in step S106 to the robot 10 (step S108). Step S108 corresponds to the third step of the present invention. In the present embodiment, the searched route is output to the robot. However, the route may be output to the output device 36 or the like so that the user can check it.

  According to the present embodiment, by optimizing the route searched by the RRT using the road map method, a route that can withstand practical use can be found in a short time. In addition, the road map method is a method that does not increase the amount of calculation even if the number of axes increases. Therefore, by using the road map method for route optimization, the robot path having a large number of axes can be searched efficiently. be able to.

  In the present embodiment, the process for performing the road map method (step S106) is performed once, but step S106 may be repeated. For example, an arbitrary number of times may be stored in the memory 32, and the road map method execution unit 303 may repeatedly perform the process of step S106 for that number of times. The arbitrary number of times may be set in advance, or may be set by the user via the input device 35.

<Route search process (second form)>
FIG. 9 is a flowchart showing the flow of the route search process (second form). 10 and 11 are diagrams for explaining the route search process (second form). This process is started, for example, when a search start instruction is input via a button or the like (not shown). In addition, about the part same as a route search process (1st form), the same code | symbol is attached | subjected and description is abbreviate | omitted. In addition, in FIGS. 10 and 11, similarly to the route search process (first form), the nodes are shown as positions on the plane in order to simplify the description.

  The RRT path finding unit 301 acquires an image of an area including the movement start position and the target position of the movable unit 11 from the imaging unit 20, and sets an operable range on the acquired image (step S100).

  The RRT route discovery unit 301 executes RRT within the operable range and searches for a route (step S102). The RRT route discovery unit 301 outputs the information on the route searched in step S102 to the road map method execution unit 303.

  Based on the route output from the RRT route finding unit 301, the road map creating unit 303A sets a range A, which is a range for executing the road map method, on the image acquired in step S100 (step S104). Then, the road map method execution unit 303 executes the road map method within the range A set in step S104 (step S106).

  Further, the road map method execution unit 303 performs route re-search using the road map method (steps S110 to S112). The road map creation unit 303A sets a range B that is smaller than the range A and includes the route searched in step S106 within the operable range (step S110). Range B corresponds to the second range of the present invention.

  FIG. 10 is a diagram illustrating a state in which the range B is set within the operable range. In FIG. 10, three ranges B are set. The range B is all smaller than the range A. Further, the range B includes the route searched in step S106 shown in FIG. Then, by setting all the ranges B, the routes searched in step S106 are all included in the ranges B.

  In particular, FIG. 10 is characterized in that the range B includes at least one node constituting the route searched in step S106. This is because by including at least one node in this way, there is a high possibility that a route can be shortcut. Also, by narrowing the range, the number of nodes can be reduced and the processing can be accelerated.

  For example, the road map creation unit 303A sets the node that is closest to the movement start position S or the movement start position S as a vertex (start point), and the node also comes to a vertex that faces the vertex (start point). The range B is set so as to include one. In FIG. 10, the nodes are arranged at the corners of the range B, but the nodes do not have to be arranged at the corners of the range B. For example, a node may be a vertex between nodes. For example, the road map creation unit 303A may set the range B by equally dividing the movement start position S and the target position G.

  The road map method execution unit 303 executes the road map method within the range B set in step S110 (step S112). Step S112 corresponds to the fourth step of the present invention. Specifically, for all the ranges B, the road map creation unit 303A sets a node, and the shortest path detection unit 303B searches for the shortest distance from among the set nodes, and uses the road map method. To determine the route searched for. The route searched by the road map method in step S112 corresponds to the third movement route of the present invention. FIG. 11 shows a route determined using the node shown in FIG. It can be seen that the route shown in FIG. 11 is improved from the route searched by the first road map method shown in FIG.

  In steps S104 and S106, since the road map method is performed with the entire route searched in step S102 as the range (range A), there is still a possibility that the route is obviously optimized and a node is selected for a useless range. Therefore, in steps S110 and S112, the found route is divided into several parts and re-searched. As a result, it is possible to search by excluding a portion that may create a useless route. In addition, since the target range of one road map method is narrow, the number of nodes to be set can be reduced, and each process is performed in a very short time. Thereby, the whole calculation time can be shortened.

  The road map method execution unit 303 outputs the route searched in step S106 to the robot 10 (step S113). Step S113 and step S108 (see FIG. 4) are the same except for the route that is output.

  According to the present embodiment, a better route can be found by repeating a small-scale road map method a plurality of times. Further, since the road map method is used, it is possible to easily perform a re-search even after the route is output once. As a result, a better route can be searched.

  In this embodiment, the re-search is performed only once, but the re-search may be performed a plurality of times. In this case, the search result is stored in the memory 32, and the road map method execution unit 303 reads it and performs a search again. FIG. 12 shows an example in which a second re-search is performed. By performing the re-search shown in FIG. 12, the route is shorter than the route shown in FIG. In this way, by repeatedly updating the route, it is possible to continue updating to a higher-quality route while using the system.

  When performing a re-search, it is desirable to perform the road map method over a wide range as long as the number of re-searches is small, and to perform the road map method with a narrow range as the number of re-searches increases. Thereby, a search can be performed efficiently.

  Further, at the time of re-searching (steps S110 and S112), an image captured by the capturing unit 20 may be acquired or acquired separately from acquiring an image captured by the capturing unit 20 first (step S100). You don't have to. If it is assumed that the environment around the robot 10 does not change, it is not necessary to acquire an image captured by the imaging unit 20. However, when performing a re-search, it may be possible to perform a re-search after a certain amount of time has elapsed since the first search. In this case, it is desirable that the road map method execution unit 303 obtains again the image captured by the imaging unit 20 before performing the process. Then, if the environment around the robot 10 does not change from the time of the first search, the search is performed again. If the environment around the robot 10 changes from the time of the first search, the search may be restarted from the beginning. Good.

  In the present embodiment, the range B is set so that all the routes searched in step S106 are included in the range B. However, it is sufficient that at least one range B is set. Thereby, processing can be performed in a shorter time.

  Furthermore, the range B can be set such that all the routes searched in step S106 are included in the range B and a part of the range B overlaps. FIG. 13 shows a state where the range B (in this case, the ranges B1 to B4) is set so that a part of the range B overlaps. When the range B is set in this way, the road map method execution unit 303 executes the road map method from the range closest to the movement start position S (or includes the movement start position S) and gradually starts from the movement start position S. What is necessary is just to perform the road map method with respect to the range which goes away. In FIG. 13, the road map method may be executed in the order of range B1, range B2, range B3, and range B4.

  Further, the user may be able to set the range B (one or more). For example, the road map method execution unit 303 may output the searched route to the output device 36 so that the user inputs the range B through the input device 35. The road map method execution unit 303 may output the result of setting the range B to the output device 36 so that the user can input the correction of the range B via the input device 35. This is made possible by the road map method execution unit 303 outputting an image (for example, FIG. 10) including the search result, the range B, and the like to the output device 36 and inputting it via the input device 35 by the user.

<Route search process (third form)>
FIG. 14 is a flowchart showing the flow of the route search process (third form). FIG. 15 is a diagram for explaining route search processing (third embodiment). This process is started, for example, when a search start instruction is input via a button or the like (not shown). In addition, about the part same as a route search process (1st form) and a route search process (2nd form), the same code | symbol is attached | subjected and description is abbreviate | omitted. Further, in FIG. 14, similarly to the route search process (first form), the node is shown as a position on the plane in order to simplify the description.

  The RRT path finding unit 301 acquires an image of an area including the movement start position and the target position of the movable unit 11 from the imaging unit 20, and sets an operable range on the acquired image (step S100).

  The RRT route discovery unit 301 executes RRT within the operable range and searches for a route (step S102). The RRT route discovery unit 301 outputs the information on the route searched in step S102 to the road map method execution unit 303.

  Based on the route output from the RRT route finding unit 301, the road map creating unit 303A sets a range A, which is a range for executing the road map method, on the image acquired in step S100 (step S104). Then, the road map method execution unit 303 executes the road map method within the range A set in step S104 (step S106).

  Further, the road map method execution unit 303 performs route re-search using the road map method (steps S110 to S112). The road map method execution unit 303 generates the route searched in step S112 as the route B. Step S112 corresponds to the fourth step of the present invention, and route B corresponds to the third movement route of the present invention.

  In addition, the road map method execution unit 303 performs a search again for a route different from the route B using the road map method (steps S114 to S116). The road map creation unit 303A sets, within the operable range, a range C that is a range that is smaller than the range A, is different from the range B, and includes the route searched in step S106 (step S106). S114). The range C corresponds to the third range of the present invention.

  FIG. 15 is a diagram illustrating a state in which the range C is set within the operable range. In FIG. 15, three ranges C are set, but all are smaller than the range A. Further, the range C, like the range B, includes the route searched in step S106 shown in FIG. Further, the range C, like the range B, includes at least one node constituting the route searched in step S106. Further, the range C is different from the range B shown in FIG.

  In FIG. 15, by setting all the ranges C, the routes searched in step S <b> 106 are all included in the ranges C. Note that the range C is not necessarily set to include all the routes searched in step S106. The range C may be one.

  The road map method execution unit 303 executes the road map method within the range C set in step S114 (step S116). Step S116 corresponds to the fifth step of the present invention. Specifically, for all the ranges C, the road map creation unit 303A sets a node, and the shortest path detection unit 303B searches for the shortest distance from the set many nodes, and uses this as the path C. decide. The route C corresponds to the fourth movement route of the present invention. The dotted line in FIG. 15 is a route searched by the first road map method shown in FIG. 10, and the solid line in FIG. 15 shows the route searched in step S116. It can be seen that the route (route C) indicated by the solid line in FIG. 15 is improved from the route searched by the first road map method.

  The roadmap method execution unit 303 evaluates the costs of the route B generated in step S112 and the route C generated in step S116, respectively, and determines which route is the route with the lower cost ( Step S118). Step S118 corresponds to the sixth step of the present invention. The cost includes power consumption (energy), moving distance, moving time, total amount of change in the angle of the joint 12, and the like. In the present embodiment, the cost is described as a movement distance. Note that the cost evaluation can be performed using a known method, and thus the description thereof is omitted.

  This will be described using a specific example. The road map method execution unit 303 obtains the movement distance of the route B shown in FIG. 11 and obtains the movement distance of the route C shown by the solid line in FIG. Then, the road map method execution unit 303 compares the movement distance of the route B with the movement distance of the route C. As a result, since the travel distance of the route C is shorter, the road map method execution unit 303 determines that the route C is a route with a lower cost.

  The road map method execution unit 303 outputs the route determined to be low in step S118 to the robot 10 (step S120). Step S120 corresponds to the third step of the present invention.

  According to this embodiment, it is possible to search for a better route without significantly increasing the calculation time.

  In this embodiment, two routes of route B and route C are generated, the costs of the two routes are compared, and a route with a low cost is output. However, the number of routes with which costs are compared is limited to this. I can't. For example, three or more routes may be generated and the costs of these routes may be compared.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be made to the above-described embodiment. In addition, it is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention. In particular, the present invention is not limited to a robot system in which a robot and a control unit and a photographing unit are provided separately, but can also be provided as a robot including a control unit and a photographing unit in the robot, or only the control unit, Or it can also provide as a search device which consists of a control part and an imaging part. The present invention can also be provided as a program for controlling a robot or the like or a storage medium storing the program.

1: robot system, 10: robot, 11: movable part, 12: joint, 13: link, 14: hand, 20: photographing part, 30: control part, 31: CPU, 32: memory, 33: external storage device, 34: Communication device, 35: Input device, 36: Output device, 37: Reading / writing device, 40: Work table, 101: Operation control unit, 301: RRT route discovery unit, 302: Collision detection unit, 303: Road map method execution , 303A: road map creation unit, 303B: shortest path detection unit

Claims (10)

A route search method for searching for a route along which a moving part of a robot moves from an initial posture to a target posture,
A first step of generating a first movement path of the robot by executing RRT (Rapidly-Exploring Random Trees) within a search range including the initial posture and the target posture;
A second step of generating a second movement path different from the first movement path by executing a roadmap method within a first range including the first movement path;
A third step of outputting the second movement route as a searched route;
A route search method characterized by comprising: The route search method according to claim 1,
In the first step, the first path connecting a plurality of first points is generated,
In the second step, a point between the first point and the first point is set as a second point, a plurality of points are selected from the second points, and the selected points are selected. A route search method comprising connecting points to generate the second movement route. In the route search method according to claim 1 or 2,
A fourth step performed between the second step and the third step, the second step being narrower than the first range and including a part of the second movement path. A fourth step of generating a third movement path different from the second movement path by performing a roadmap method at
In the third step, the third movement route is output instead of the second movement route. The route search method according to claim 3,
In the fourth step, the second range is set so as to include at least one of the first points. In the route search method according to claim 3 or 4,
In the fourth step, the third range is generated by setting a plurality of the second ranges at different positions and executing a road map method inside each of the set second ranges. A route search method characterized by: In the route search method according to any one of claims 3 to 5,
A fifth step performed between the fourth step and the third step, which is narrower than the first range, includes a part of the second movement path, and the second step A fifth step of generating a fourth movement path different from the third movement path by performing a roadmap method in a third range different from the range;
A sixth step performed between the fifth step and the third step for evaluating which of the third route and the fourth route is a better route; 6 steps,
In the third step, instead of the second movement route, a route evaluated as a better route in the sixth step is output. A route search device for searching for a route along which a movable part of a robot moves from an initial posture to a target posture,
First movement path generation means for generating a first movement path of the robot by executing RRT (Rapidly-Exploring Random Trees) within a search range including the initial posture and the target posture;
A second movement path generation means for generating a second movement path different from the first movement path by executing a road map method within a first range including the first movement path;
Output means for outputting the second movement route as a searched route;
A route search device characterized by comprising: A robot control device for controlling a robot having a movable part,
First movement path generation means for generating a first movement path of the robot by executing RRT (Rapidly-Exploring Random Trees) within a search range including an initial posture and a target posture of the movable part;
A second movement path generation means for generating a second movement path different from the first movement path by executing a road map method within a first range including the first movement path;
Output means for outputting the second movement route to the robot as a searched route;
A robot control apparatus comprising: A movable part formed to be movable from an initial posture to a target posture;
First movement path generation means for generating a first movement path of the robot by executing RRT (Rapidly-Expanding Random Trees) within a search range including the initial posture and the target posture;
A second movement path generation means for generating a second movement path different from the first movement path by executing a road map method within a first range including the first movement path;
Control means for controlling the moving means as the searched route for the second moving route;
A robot characterized by comprising: A program for searching for a path along which the moving part of the robot moves from the initial posture to the target posture,
A first step of generating a first movement path of the robot by executing RRT (Rapidly-Exploring Random Trees) within a search range including the initial posture and the target posture;
A second step of generating a second movement path different from the first movement path by executing a roadmap method within a first range including the first movement path;
A third step of outputting the second movement route as a searched route;
A program that causes an arithmetic device to execute.

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