Robot route plan creation system and robot route plan creation method

Abstract

A route plan creation unit (104) creates a route plan including the scheduled travel route of a plurality of robots (R) and the scheduled passage time of each point on the scheduled travel route. A collision determination unit (107) determines whether or not a collision between the robots (R) will occur on the basis of the route plan and the current position of each robot (R). When it is determined that a collision between robots (R) will occur, a route switching point setting unit (108) sets a route switching point on the scheduled travel route of each robot (R), and a route plan correction unit (109) causes the route plan creation unit (104) to create a new route plan for each robot (R) having the route switching point as a departure point. The route plan correction unit (109) changes the route plan of each robot (R) by replacing a portion prior to the route switching point in the route plan of each robot (R) with a new route plan.

Description

Robot path planning system and robot path planning method

[0001] The present disclosure relates to a technique for creating a path plan for operating multiple robots.

[0002] For example, Patent Document 1 below discloses a technology for operating multiple transport robots. The technology in Patent Document 1 prevents collisions between moving bodies by imposing restrictions on the travel area of ​​each robot.

[0003] International Publication No. 2022 / 113992

[0004] In the technology of Patent Document 1, the movement route of the moving object with the highest priority among multiple moving objects can be planned without any constraints, but the movement routes of moving objects with lower priority have more constraints, resulting in reduced transportation efficiency. Also, in environments with a lot of people, such as hospitals and commercial facilities, even if an operation plan is made to prevent robots from colliding with each other, there is a concern that the operation may not proceed as planned due to the influence of the people, resulting in collisions between robots.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide technology that can prevent a decrease in transport efficiency while preventing collisions between robots even when operations do not proceed as planned.

[0006] A robot path planning system according to the present disclosure includes a path planning unit that creates a path plan including planned travel paths for multiple robots and planned times of passing through each point on the planned travel paths based on map data; a current position acquisition unit that acquires the current position of each robot; a collision determination unit that determines whether a collision will occur between the robots based on the path plan and current position of each robot; a path switching point setting unit that sets a path switching point on the planned travel paths of each robot when it is determined that a collision will occur between the robots; and a path plan correction unit that, when a path switching point is set on the planned travel path of each robot, causes the path planning unit to create a new path plan for each robot that starts from the path switching point, and corrects the path plan of each robot by replacing the portion of the path plan of each robot beyond the path switching point with the new path plan.

[0007] According to the present disclosure, collisions between robots can be prevented even when operation does not proceed as planned. Furthermore, if it is determined that a collision will occur, the path plans of each robot are revised, thereby preventing a decrease in transportation efficiency.

[0008] The objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0009] FIG. 1 is a diagram illustrating a configuration of a robot path planning system according to embodiment 1. FIG. 2 is a flowchart illustrating the operation of the robot path planning system according to embodiment 1. FIG. 3 is a flowchart illustrating a path planning process. FIG. 4 is a flowchart illustrating a collision detection process. FIG. 5 is a flowchart illustrating a path switching point setting process. FIG. 6 is a flowchart illustrating a path planning integration process. FIG. 7 is a flowchart illustrating a path switching point setting process in embodiment 2. FIG. 8 is a flowchart illustrating a path planning process in embodiment 3. FIG. 9 is a flowchart illustrating a path switching point setting process in embodiment 4. FIG. 10 is a diagram illustrating an example of a hardware configuration of a robot path planning system.

[0010] <First Embodiment> Fig. 1 is a diagram showing the configuration of a robot path planning system 100 according to a first embodiment. The robot path planning system 100 creates a path plan for operating a plurality of robots R and transmits it to each robot R. The "path plan" here refers to information including a planned travel route for the robot R and a planned time of passing each point on the planned travel route. The robot R that receives the path plan operates in accordance with the path plan. Therefore, the robot path planning system 100 can also be said to be a control system that manages and controls the operation of a plurality of robots R.

[0011] 1 shows an example in which the robot path planning system 100 controls the operations of four robots R, namely, robots R1 to R4. The robots R may be used for any purpose. In this embodiment, the robots R are assumed to be transport robots that transport objects.

[0012] The robot path planning system 100 includes a communication unit 101, a map data management unit 102, a point setting unit 103, a path planning unit 104, a path plan storage unit 105, a current position acquisition unit 106, a collision determination unit 107, a path switching point setting unit 108, and a path plan correction unit 109.

[0013] The communication unit 101 is a communication device that enables the robot path planning system 100 to communicate with the robot R wirelessly.

[0014] The map data management unit 102 has a storage medium that stores map data of locations where the robot R is operated (for example, factories, hospitals, commercial facilities, accommodation facilities, etc.), and manages the map data. The map data stored in the map data management unit 102 includes information such as the coordinates of each location required for the operation of the robot R, the travel speed between each location, and the passable directions between each location.

[0015] The point setting unit 103 sets points such as a starting point, waypoints, and destination point of each robot R. Each point may be specified to the point setting unit 103 by any method, such as manual input by a system administrator, input of a data file indicating each point, or transmission of a message indicating each point. Furthermore, the point setting unit 103 may set the current position of the robot R acquired by the current position acquisition unit 106 as the starting point of the robot R. Furthermore, the information on the starting point may include information on the time of departure from the starting point.

[0016] The path planning unit 104 creates a path plan for each of the multiple robots R. Specifically, the path planning unit 104 plans a planned driving route from the starting point to the destination point for each robot R, and a planned time to pass each point on the planned driving route, based on the map data stored in the map data management unit 102. If a departure time from the starting point for each robot R is specified, the path planning unit 104 creates a path plan taking this into consideration. At this time, the path planning unit 104 creates a path plan for each robot R so that collisions between the robots R do not occur. A general path search method, such as a conflict-based search method, may be used as a search method for the planned driving route.

[0017] Specific examples of the route plan include a route plan for collecting transported items at a starting point and a waypoint and transporting them to a destination point, a route plan for delivering multiple packages at a starting point to waypoints and a destination point, etc. In the following, for the sake of simplicity, the location setting unit 103 will be described as setting only the starting point and the destination point of each robot R (setting of waypoints will be omitted).

[0018] The path plan storage unit 105 is a storage medium that stores the path plan of each robot R created by the path plan creation unit 104. The path plan creation unit 104 stores the created path plan of each robot R in the path plan storage unit 105 and transmits it to each robot R via the communication unit 101.

[0019] The current position acquisition unit 106 acquires current position information transmitted from each robot R via the communication unit 101. In this embodiment, the robot R periodically transmits information on its own current position to the robot path planning system 100.

[0020] The collision determination unit 107 determines whether or not a collision will occur between the robots R, based on the path plan of each robot R acquired by the current position acquisition unit 106 and the current position of each robot R stored in the path plan storage unit 105. That is, the collision determination unit 107 predicts the time at which the robot R will actually pass each point on the planned travel path, based on the current position and path plan of the robot R, and determines that a collision will occur between the robots R if it is predicted that two or more robots R will pass the same point at the same time. Furthermore, if the collision determination unit 107 determines that a collision will occur between the robots R, it specifies the predicted collision point and the predicted collision time.

[0021] As described above, the path plans for each robot R are created so that collisions between the robots R do not occur. However, for example, in an environment with a flow of people or an environment where the robots R use elevators, even if a path plan is created to prevent collisions between the robots R, the robots R may not be able to travel according to the path plan due to the influence of the flow of people or waiting times for the elevator, and collisions between the robots may occur. The collision determination unit 107 compares the current position of the robot R with the position planned in the path plan (hereinafter referred to as the "planned position"), calculates the delay time or lead time (advance time) of the robot R relative to the path plan, and predicts the time at which the robot R will pass each point on the planned travel route. If there is a point where the predicted passage times of different robots R overlap, the collision determination unit 107 determines that the robots R will pass that point at the same time and determines that a collision between the robots R will occur.

[0022] When it is determined that a collision between the robots R will occur, the route switching point setting unit 108 sets a route switching point on the planned travel route of each robot R. The route switching point is a point for switching the planned travel route to a route that avoids collision between the robots R, and is set before the predicted collision point, i.e., on the planned travel route between the current position of the robot R and the predicted collision point. Furthermore, the route switching point setting unit 108 sets route switching points on the planned travel routes of all the robots R, including the robots R that will not collide. There is no predicted collision point on the planned travel route of the robot R that will not collide, but in that case, the route switching point may be set on the planned travel route between the current position of the robot R and the destination point.

[0023] When a route switching point is set on the planned travel route of each robot R, the route plan correction unit 109 causes the route plan creation unit 104 to create a new route plan for each robot R that starts from the route switching point. At this time, too, the route plan creation unit 104 creates a new route plan for each robot R so that collisions between the robots R do not occur. Then, the route plan correction unit 109 replaces the portion of the route plan for each robot R beyond the route switching point with the new route plan. In this way, the route plan for each robot R is corrected so that collisions between the robots R do not occur. Note that it is not prevented that the corrected route plans of some robots R will be the same as the route plans before correction.

[0024] In the present embodiment, an example is shown in which all of the communication unit 101, map data management unit 102, point setting unit 103, route plan creation unit 104, route plan storage unit 105, current position acquisition unit 106, collision determination unit 107, route switching point setting unit 108, and route plan correction unit 109 are built into the robot path planning system 100, but some or all of these may be located in the robot R or other devices (such as a server). In other words, the robot path planning system 100 may be constructed by a plurality of devices operating in cooperation with each other, and the robot R may be included in the plurality of devices.

[0025] Next, the operation of the robot path planning system 100 according to the first embodiment will be described with reference to the flowcharts of FIGS.

[0026] 2 is a flowchart showing the overall operation of the robot path planning system 100 according to Embodiment 1. When the robot path planning system 100 is started, a path planning process is performed to create a path plan for each robot R (step S101).

[0027] 3 is a flowchart of the path planning process. The path planning process is performed for all robots R controlled by the robot path planning system 100.

[0028] First, the location setting unit 103 sets the starting point and the destination point of the robot R (steps S201 and S202). If the information on the starting point includes a specification of the departure time from the starting point (YES in step S203), the location setting unit 103 also sets the departure time of the robot R (step S204).

[0029] Next, the route planning unit 104 creates a route plan including a planned travel route from the departure point to the destination point of each robot R and a planned time of passing each point on the planned travel route, based on the map data stored in the map data management unit 102 (step S205). At this time, the route planning unit 104 creates a route plan for each robot R so that collisions between the robots R do not occur.

[0030] When the route plan creation unit 104 stores the created route plan in the route plan storage unit 105 (step S206), the route plan creation process ends.

[0031] 2, when the path plan creation process (step S101) for all the robots R is completed, the communication unit 101 transmits the path plan to each robot R (step S102). Each robot R operates according to the received path plan.

[0032] Thereafter, the robot path planning system 100 executes a collision determination process for determining whether or not a collision between the robots R will occur.

[0033] 4 is a flowchart of the collision determination process. In the collision determination process, the collision determination unit 107 acquires information on the current position of each robot R acquired by the current position acquisition unit 106 (step S301). Next, the collision determination unit 107 calculates the planned position of each robot R at the current time based on the path plan for each robot R stored in the path plan storage unit 105 (step S302). The collision determination unit 107 compares the current position of each robot R with the planned position (step S303) and calculates the delay time or lead time of each robot R relative to the path plan (step S304). Then, the collision determination unit 107 calculates the predicted passage time of each robot R at each point from the delay time or lead time of each robot R (step S305).

[0034] Next, the collision determination unit 107 refers to the calculation results of the predicted passage times of each robot R for each point, and checks whether there are any points where the predicted passage times of different robots R overlap (step S306). If there are any points where the predicted passage times of different robots R overlap (YES in step S306), the collision determination unit 107 determines that a collision will occur between the robots R, specifies the predicted collision point and the predicted collision time (step S307), and the collision determination process ends. If there are no points where the predicted passage times of different robots R overlap (NO in step S306), the collision determination unit 107 determines that a collision will not occur between the robots R (step S308), and the collision determination process ends.

[0035] 2 , if it is determined that no collision will occur between the robots R as a result of the collision determination process (step S103) (NO in step S104), the robot path planning system 100 checks whether or not the operation of the robot R has ended (step S105). If the operation of the robot R has ended (YES in step S105), the robot path planning system 100 ends its operation, and if the operation of the robot R is continuing (NO in step S105), the process returns to step S103.

[0036] If, as a result of the collision determination process (step S103), it is determined that a collision will occur between robots R (YES in step S104), a route switching point setting process is carried out to set a route switching point on the planned travel route of each robot R (step S106).

[0037] 5 is a flowchart of the route switching point setting process. The route switching point setting process is performed for all robots R controlled by the robot route planning system 100.

[0038] In the route switching point setting process, the route switching point setting unit 108 acquires information on the current position of the robot R acquired by the current position acquisition unit 106 (step S401). Then, the route switching point setting unit 108 sets a route switching point on the planned travel route between the current position of the robot R and the predicted collision point (step S402). Note that for robot R with which no collision will occur, the predicted collision point is set at any point between the current position of the robot R and the destination point.

[0039] 2 , when the path switching point setting process (step S106) is completed for all the robots R, the path plan correction unit 109 executes a path planning process (step S107) in which the path planning unit 104 creates a new path plan for each robot R that starts from the path switching point. The path planning process of step S107 is also executed for all the robots R controlled by the robot path planning system 100, similar to the path planning process of step S101.

[0040] The route plan creation process in step S107 is the same as that in Fig. 3. However, in step S107, a route switching point is set as the starting point. Therefore, in step S107, the route plan creation unit 104 creates a new route plan from the route switching point to the destination point.

[0041] When the path plan creation process in step S107 is completed, a path plan integration process is carried out to integrate the current path plan of each robot R with the new path plan (step S108).

[0042] 6 is a flowchart of the path plan integration process. The path plan integration process is also performed for all robots R controlled by the robot path planning system 100. In the path plan integration process, the path plan correction unit 109 acquires the current path plan of the robot R stored in the path plan storage unit 105 and the new path plan of the robot R created in step S107 (steps S501 and S502). The path plan correction unit 109 then replaces the portion of the path plan of the robot R beyond the path switching point with the new path plan, thereby integrating the current path plan of the robot R with the new path plan (step S503). This corrects the path plan of the robot R so that collisions between the robots R do not occur. Note that the corrected path plans of some robots R may be the same as the path plans before correction.

[0043] When the path plan correction unit 109 stores the corrected path plan for the robot R in the path plan storage unit 105, the path plan integration process ends.

[0044] 2, when the path plan integration process (step S108) for all the robots R is completed, the communication unit 101 transmits the corrected path plan to each robot R (step S109). Then, the process returns to step S103.

[0045] According to the robot path planning system 100 of this embodiment, even if the operation of the robot R does not proceed according to the path plan, the path plan can be corrected to prevent collisions between the robots R. Furthermore, if it is determined that a collision will occur, the path plans of not only the robot R that caused the collision but also each robot are reviewed, thereby preventing a decrease in transportation efficiency.

[0046] <Embodiment 2> The configuration of a robot path planning system 100 according to embodiment 2 is the same as that of embodiment 1 (Fig. 1). The operation of the robot path planning system 100 according to embodiment 2 is also basically the same as that of embodiment 1, except for the route switching point setting process performed in step S106 in Fig. 2, which differs from that of embodiment 1. Therefore, the route switching point setting process according to embodiment 2 will be described here, and descriptions of other processes will be omitted.

[0047] In the second embodiment, the time t (hereinafter simply referred to as "time t") required for the path planning unit 104 to create a new path plan from the path switching point to the destination point is set in advance in the robot path planning system 100, and the path switching point setting unit 108 determines the position of the path switching point taking into account the time t. Specifically, the path planning unit 104 sets the path switching point on the planned traveling route between the position of the robot R after the time t and the predicted collision point.

[0048] 7 is a flowchart of the route switching point setting process in embodiment 2. In the route switching point setting process in embodiment 2, the route switching point setting unit 108 acquires information on the current position of the robot R acquired by the current position acquisition unit 106 (step S411). The route switching point setting unit 108 also calculates the position of the robot R after time t (step S412). Then, the route switching point setting unit 108 sets a route switching point on the planned travel route between the position of the robot R after time t and the predicted collision point (step S413).

[0049] According to the robot path planning system 100 of the second embodiment, the predicted collision point is set ahead of the position of the robot R after time t (the time required to create a new path plan), which prevents the robot R from arriving at the predicted collision point before a new path plan is created. If the robot R arrives at the predicted collision point before a new path plan is created, it becomes necessary to make the robot wait until a new path plan is created; however, this is prevented in the second embodiment, which enables efficient operation of the robot R.

[0050] <Embodiment 3> The configuration of a robot path planning system 100 according to embodiment 3 is the same as that of embodiment 1 (Fig. 1). The operation of the robot path planning system 100 according to embodiment 3 is also basically the same as that of embodiment 1, except for the path planning process performed in step S101 of Fig. 2, which differs from that of embodiment 1. Therefore, the path planning process according to embodiment 3 will be described here, and descriptions of other processes will be omitted.

[0051] In the third embodiment, the map data management unit 102 can set, on the map indicated by the map data, a no-waiting area for the robot R. The no-waiting area for the robot R is a place where stopping the robot R would be dangerous for passersby or a place that would obstruct the movement of passersby, such as near areas where people get on and off elevators or escalators.

[0052] The path planning unit 104 creates a path plan that prevents each robot R from waiting in a no-wait area, thereby preventing the robot R from endangering passersby or obstructing their movement.

[0053] FIG. 8 is a flowchart of a route planning process according to the third embodiment.

[0054] First, the location setting unit 103 sets the starting point and the destination point of the robot R (steps S211 and S212). If the information on the starting point includes a specification of the departure time from the starting point (YES in step S213), the location setting unit 103 also sets the departure time of the robot R (step S214).

[0055] Next, the path planning unit 104 creates a path plan including a planned travel route from the departure point to the destination point of each robot R and a planned time of passing each point on the planned travel route, based on the map data (including information on no-wait zones for the robot R) stored in the map data management unit 102 (step S215). At this time, the path planning unit 104 creates a path plan for each robot R so that collisions between the robots R do not occur and each robot R does not wait in a no-wait zone.

[0056] When the route plan creation unit 104 stores the created route plan in the route plan storage unit 105 (step S216), the route plan creation process ends.

[0057] <Fourth Embodiment> The configuration of a robot path planning system 100 according to a fourth embodiment is the same as that of the first embodiment (Fig. 1). The operation of the robot path planning system 100 according to the fourth embodiment is also basically the same as that of the first embodiment, except for the route switching point setting process performed in step S106 in Fig. 2, which differs from that of the first embodiment. Therefore, the route switching point setting process according to the fourth embodiment will be described here, and descriptions of the other processes will be omitted.

[0058] In the fourth embodiment, the map data management unit 102 can set a route switching prohibited area on the map shown by the map data, where the setting of a route switching point is prohibited. The route switching prohibited area is a place where a change in the operation of the robot R would be dangerous to passersby, a place that would obstruct the flow of passersby, or a place that would reduce the operational efficiency of the robot R. For example, it can be a place similar to a no-wait area for the robot R, such as near an elevator or escalator boarding or disembarking area.

[0059] The route switching point setting unit 108 sets the route switching point at a location other than the route switching prohibited area, thereby preventing the robot R from endangering passersby, obstructing the movement of passersby, or slowing down the operation of the robot R.

[0060] 9 is a flowchart of the route switching point setting process in embodiment 4. In the route switching point setting process in embodiment 4, the route switching point setting unit 108 acquires information on the current position of the robot R acquired by the current position acquisition unit 106 (step S421). Then, the route switching point setting unit 108 sets a route switching point at a location other than the route switching prohibited area on the planned travel route between the current position of the robot R and the predicted collision point (step S422). Note that for robots R with which a collision will not occur, the predicted collision point is set at a location other than the route switching prohibited area between the current position of the robot R and the destination point.

[0061] The fourth embodiment may be combined with the second embodiment. That is, the route switching point setting unit 108 may set a route switching point at a location other than the route switching prohibited area on the planned travel route between the position of the robot R after the time t (the time required to create a new route plan) and the predicted collision point.

[0062] 10 and 11 are diagrams illustrating examples of the hardware configuration of the robot path planning system 100. The functions of the components of the robot path planning system 100 illustrated in FIG. 1 are realized, for example, by a processing circuit 50 illustrated in FIG. 10. That is, the robot path planning system 100 includes the processing circuit 50 for: creating a route plan including planned travel routes for multiple robots and planned times of passage at each point on the planned travel routes based on map data; acquiring the current positions of each robot; determining whether or not a collision will occur between the robots based on the path plans and the current positions of each robot; setting a route switching point on the planned travel routes of each robot if it is determined that a collision will occur between the robots; creating a new route plan for each robot that starts from the route switching point when the route switching point is set on the planned travel route of each robot; and correcting the route plan for each robot by replacing the portion of the path plan for each robot beyond the route switching point with the new route plan. The processing circuit 50 may be dedicated hardware, or may be configured using a processor (also called a central processing unit (CPU), processing device, arithmetic unit, microprocessor, microcomputer, or DSP (Digital Signal Processor)) that executes a program stored in memory.

[0063] When processing circuitry 50 is dedicated hardware, processing circuitry 50 may be, for example, a single circuit, a multiple circuit, a programmed processor, a parallel programmed processor, an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination thereof. The functions of each component of robot path planning system 100 may be implemented by a separate processing circuit, or the functions may be implemented together by a single processing circuit.

[0064] 11 shows an example of the hardware configuration of the robot path planning system 100 when the processing circuitry 50 is configured using a processor 51 that executes a program. In this case, the functions of the components of the robot path planning system 100 are realized by software or the like (software, firmware, or a combination of software and firmware). The software or the like is written as a program and stored in the memory 52. ​​The processor 51 realizes the function of each part by reading and executing the program stored in the memory 52. That is, the robot path planning system 100 includes a memory 52 for storing a program that, when executed by the processor 51, results in the following: creating a path plan, based on map data, for multiple robots, including planned travel paths and planned times of passage at each point on the planned travel paths; acquiring the current positions of each robot; determining whether a collision will occur between the robots based on the path plans and current positions of each robot; setting a path switching point on the planned travel path of each robot if it is determined that a collision will occur between the robots; and, once a path switching point has been set on the planned travel path of each robot, creating a new path plan for each robot that starts at the path switching point and correcting the path plan for each robot by replacing the portion of the path plan for each robot beyond the path switching point with the new path plan. In other words, this program can be said to cause a computer to execute the procedures and methods of operation of the components of the robot path planning system 100.

[0065] Here, the memory 52 may be, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), or an EEPROM (Electrically Erasable Programmable Read Only Memory), a HDD (Hard Disk Drive), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disc), and a drive device for such a disk, or any other storage medium that will be used in the future.

[0066] The above describes a configuration in which the functions of the components of the robot path planning system 100 are realized either by hardware or software, etc. However, the present invention is not limited to this, and the robot path planning system 100 may be configured such that some of the components are realized by dedicated hardware and other components are realized by software, etc. For example, the functions of some of the components may be realized by the processing circuitry 50 as dedicated hardware, and the functions of other components may be realized by the processing circuitry 50 as the processor 51 reading and executing a program stored in the memory 52.

[0067] As described above, the robot path planning system 100 can realize the above-described functions by hardware, software, or a combination of these.

[0068] It is possible to freely combine the embodiments, and to modify or omit the embodiments as appropriate.

[0069] The above description is illustrative in all respects, and it is understood that countless variations not illustrated can be envisioned.

[0070] 100 Robot path planning system, R robot, 101 Communication unit, 102 Map data management unit, 103 Point setting unit, 104 Path plan creation unit, 105 Path plan storage unit, 106 Current position acquisition unit, 107 Collision determination unit, 108 Path switching point setting unit, 109 Path plan correction unit, 50 Processing circuit, 51 Processor, 52 Memory.

Claims

1. A robot path planning system comprising: a path planning unit that creates a path plan including planned travel routes for multiple robots and planned times of passing through each point on the planned travel routes based on map data; a current position acquisition unit that acquires the current position of each of the robots; a collision determination unit that determines whether or not a collision will occur between the robots based on the path plan and the current position of each of the robots; a path switching point setting unit that sets a path switching point on the planned travel route of each of the robots when it is determined that a collision will occur between the robots; and a path plan correction unit that, when the path switching point is set on the planned travel route of each of the robots, causes the path planning unit to create a new path plan for each of the robots that has the path switching point as a starting point, and corrects the path plan of each of the robots by replacing the portion of the path plan for each of the robots beyond the path switching point with the new path plan.

2. The robot path planning system according to claim 1, wherein the path switching point setting unit determines the position of the path switching point taking into account the time required to create the new path plan.

3. A robot path planning system as described in claim 1 or claim 2, further comprising a map data management unit that manages the map data, wherein the map data management unit sets no-wait zones for the robots in the map data, and the path planning unit creates the path plan in which each of the robots does not wait in the no-wait zones.

4. A robot path planning system as described in any one of claims 1 to 3, comprising a map data management unit that manages the map data, wherein the map data management unit sets a route switching prohibited area in the map data that prohibits the setting of the route switching point, and the route switching point setting unit sets the route switching point at a location other than the route switching prohibited area.

5. A robot path planning method, in which a path planning unit of a robot path planning system creates, based on map data, a path plan including planned driving routes for multiple robots and planned times of passing through each point on the planned driving routes; a current position acquisition unit of the robot path planning system acquires the current position of each of the robots; a collision determination unit of the robot path planning system determines whether a collision will occur between the robots based on the path plan and the current position of each of the robots; if it is determined that a collision will occur between the robots, a path switching point setting unit of the robot path planning system sets a path switching point on the planned driving route for each of the robots; and when the path switching point has been set on the planned driving route for each of the robots, a path plan correction unit of the robot path planning system causes the path planning unit to create a new path plan for each of the robots that has the path switching point as a starting point, and corrects the path plan for each of the robots by replacing the portion of the path plan for each of the robots beyond the path switching point with the new path plan.

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