JP7820104B2 - Control device, mobile body, and mobile body distributed control program - Google Patents

Description

The present invention relates to a control device for moving a mobile object, a mobile object, and a distributed control program for a mobile object.

Patent Document 1 describes a mobile system in which transport vehicles and carts, etc., move autonomously and in tandem while acquiring information about the surrounding environment, without any mechanical connection, and can automatically branch off and merge.

More specifically, the mobile system includes an integrated planning means for planning travel routes for multiple mobile robots. The integrated planning means configures the multiple mobile robots as master mobile robots that move autonomously and slave mobile robots that move in response to instructions from the master mobile robot. Each of the multiple mobile robots includes at least a measurement means for measuring the surrounding environment, a communication means for communicating with the integrated planning means and other mobile robots, a master position recognition means for recognizing the position of the mobile robot, a slave position recognition means for recognizing the position of the other mobile robots, a travel planning means for planning travel routes for the mobile robot and the other mobile robots, and a travel control means for controlling the mobile mechanism in accordance with the travel planning means.

Patent No. 4920645

The objective of the present invention is to provide a control device, a mobile body, and a distributed control program for mobile bodies that enable multiple mobile bodies to move along their respective route plans while avoiding collisions under autonomous distributed control.

The control device of the present invention is a control device in a distributed control system for mobile objects that includes multiple mobile objects arranged in assigned areas where they do not interfere with each other, and that move the multiple mobile objects by acquiring position information from each other to change their assigned areas while avoiding collisions. It includes a movement information acquisition unit that acquires a route plan for the host mobile object and position information for other mobile objects, a assigned area determination unit that determines the assigned areas for the host mobile object and the other mobile objects based on the position information of the other mobile objects, and a movement control unit that determines risks in a local area including the host mobile object's position based on the route plan, calculates a target position based on the risks in the local area and the host mobile object's assigned area, and moves the host mobile object to the target position. The acquisition by the movement information acquisition unit, the determination by the assigned area determination unit, and the determination, calculation, and movement by the movement control unit are repeated at a predetermined cycle.

In the control device of the present invention, the movement information acquisition unit acquires a route plan for the host mobile unit and position information for other mobile units. The coverage area determination unit determines the coverage areas for the host mobile unit and the other mobile units based on the position information of the other mobile units. The movement control unit determines the risk for a local area including the host mobile unit's position based on the route plan, calculates a target position based on the risk in the local area and the coverage area for the host mobile unit, and moves the host mobile unit to the target position. The acquisition by the movement information acquisition unit, the determination by the coverage area determination unit, and the determination, calculation, and movement by the movement control unit are repeated at a predetermined cycle.

In this way, the risk of a local area including the position of the own mobile unit is determined based on the route plan, a target position is calculated based on the risk of the local area and the area covered by the own mobile unit, and the own mobile unit is moved to the target position, and this process is repeated. This allows multiple mobile units to move along their respective route plans while avoiding collisions under autonomous distributed control.

In addition, the movement information acquisition unit acquires position information of other mobile units using sensors in the own mobile unit.

The movement control unit also modifies the risk of the local area based on the area of responsibility of the own mobile unit, and calculates the target position from the risk of the local area after modification. Alternatively, the movement control unit calculates the target position from within the area of responsibility of the own mobile unit based on the risk of the local area.

Furthermore, the coverage area is a Voronoi region surrounded by the perpendicular bisectors between the moving bodies.

The program of the present invention is a distributed control program for a mobile object that causes a computer to operate as the above-mentioned control device.

A mobile object according to the present invention is a mobile object equipped with the above-described control device.

As described above, the present invention has the excellent effect of enabling multiple mobile objects to move along their own route plans while avoiding collisions under autonomous decentralized control.

FIG. 2 is a block diagram of a control system for operating the moving body according to the first embodiment. FIG. 2 is a plan view of a Voronoi-divided movable area according to the first embodiment. 1 is a functional block diagram of a control device for a moving body according to a first embodiment; FIG. 10 is a diagram for explaining a method for setting a potential in a local region. FIG. 10 is a diagram for explaining a method for setting a potential in a local region. 4 is a flowchart showing a distributed control routine in the control device according to the first embodiment. 5 is a flowchart showing a process flow for determining a target position in the control device according to the first embodiment. FIG. 1 is a diagram showing an example of simultaneous intersection of five moving objects at a T-junction. FIG. 1 is a diagram showing an example of simultaneous intersection of five moving objects at a T-junction. 10 is a flowchart showing a process flow for determining a target position in a control device according to a second embodiment. 10 is a flowchart showing a distributed control routine in a control device according to a third embodiment.

[First embodiment]
1 shows a mobile object 10 that is applied to a distributed control system for mobile objects according to this embodiment. Fig. 1 is a block diagram of a control system for operating the mobile object 10 that is applied to this embodiment.

Figure 2 is a plan view of area 12 of the mobile object 10. Multiple mobile objects 10 exist in area 12 and can move independently.

As shown in Figure 1, the mobile unit 10 is capable of unmanned movement within a travelable range within an area 12, and is equipped with a control device 14 equipped with a microcomputer that executes control including the movement.

The microcomputer of the control device 14 has a CPU 16A, RAM 16B, ROM 16C, an input/output port (I/O) 16D, and a bus 16E such as a data bus or control bus that connects these. An observation module 18, a movement module 20, a position recognition module 22, and a communication module 24 are connected to the I/O 16D. The observation module 18 is an example of a sensor.

The control device 14, for example, activates a distributed control program for mobile objects pre-stored in ROM 16C using the CPU 16A, controls the operation of the observation module 18, movement module 20, position recognition module 22, and communication module 24, and also functions as a movement information acquisition unit 30, a coverage area determination unit 32, and a movement control unit 34, as shown in FIG. 3.

(Observation Module 18)
A typical device applied to the observation module 18 is, for example, a camera, which captures an image of the surrounding environment from the position of the mobile body 10 .

Note that the observation module 18 is not limited to capturing images using a camera, but may also detect geographical features (landmarks) by emitting radio waves (radar, laser, ultrasound, etc.).

The observation module 18 acquires position information of other mobile units 10 (relative positional relationships with the host mobile unit 10) from the captured image of the surrounding environment. The observation module 18 also acquires position information of walls and obstacles (relative positional relationships with the host mobile unit 10) from the captured image of the surrounding environment.

(Movement module 20)
The mobile body 10 of this embodiment is a mobile module 20 that moves on the ground, and can travel toward a target position by controlling the drive and steering of the motor of a mobile robot, which is a device applied to the mobile module 20.

Note that the mobile body 10 is not limited to a mobile module 20 that moves on land, but may also be a mobile module 20 that moves on water or in the air, and multiple devices may be used in combination.

(Location Recognition Module 22)
The position recognition module 22 has a function of recognizing the position of the own mobile body 10, and is equipped with at least one sensor of the following devices to obtain position information: GPS, laser, radar, ultrasound, motion capture, camera, wireless communication, radio strength, odometry, and landmark.

The position recognition module 22 recognizes the position of the mobile unit 10 using coordinates in three-dimensional space, etc., based on the results (detection signals) detected by the sensor.

(Communication module 24)
The communication module 24 includes a wireless communication device as a device. The wireless communication function for communication between the mobile bodies 10 includes a route plan receiving unit that receives a route plan from the current position of the mobile body 10 to a final destination position from a control room that manages the overall movement of the multiple mobile bodies 10. Here, the communication cycle between the control room and the mobile bodies 10 is longer than the control cycle of the control device 14. Furthermore, communication of position information and the like may be performed between the mobile bodies 10. In this case, the communication cycle between the mobile bodies 10 is longer than the control cycle of the control device 14, and the communication cycle between the control room and the mobile bodies 10 is longer than the communication cycle between the mobile bodies 10. Furthermore, the route plan may be received from the control room each time a waypoint in the route plan is reached.

In the control device 14 of each mobile body 10, the movement information acquisition unit 30 acquires the route plan for the mobile body 10 itself and the position information of other mobile bodies 10.

In addition, the coverage area determination unit 32 performs Voronoi division on the area 12 shown in Figure 2 above based on the position information of the other mobile body 10, and determines the Voronoi areas as the coverage areas of the own mobile body 10 and the other mobile body 10.

Voronoi tessellation analyzes the sphere of influence of each point (here, the position of the mobile unit 10). When the set of points with the shortest distance to the mobile unit 10 is represented by a single polygon, each is called a Voronoi region. For example, in Figure 2, in a Voronoi tessellation on a two-dimensional plane, Voronoi edges 26, which are the boundaries of the Voronoi tessellation, are the perpendicular bisectors of the line segments connecting the mobile units 10 (the thick white lines in Figure 2), and each of the Voronoi regions (1) to (n) partitioned by the Voronoi edges 26 always contains one mobile unit 10. The variable n is the number of Voronoi tessellations, and in Figure 2, n = 3.

In this embodiment, mobile objects 10 move freely within the travelable range of area 12, and the Voronoi region changes each time.

The movement control unit 34 calculates a target position based on the potential of a local region including the position of the host mobile body 10, which is based on the path plan of the host mobile body 10, and the Voronoi region of the host mobile body 10, and controls the host mobile body 10 to move to the target position. Note that potential is an example of risk, and the lower the risk of collision, the higher the potential value.

Specifically, the movement control unit 34 sets a positive potential φ (φ>0) on the path plan within a local area centered on the current position of the host mobile unit 10, as shown in Figure 4, and also sets a negative potential φ (φ<0) on building walls, other mobile units 10, people, obstacles, etc. within the local area, as shown in Figure 5.

Figure 4 shows an example in which a positive potential φ is assigned to the path plan, and a Gaussian distribution is set with its peak on the path plan. The closer the positive potential φ is to the final target position, the larger its value. A negative potential φ is assigned to the walls. Note that the local region may also be a rectangular region.

Also, Figure 5 shows an example in which a negative potential φ is applied as a penalty to obstacle areas (areas that cannot be passed through due to the presence of an obstacle) that are set to surround at least one obstacle. The potential value φ is set to 0 on the trajectory that the mobile object 10 has passed through, and the area is forgotten.

The movement control unit 34 then modifies the potential of the local region based on the Voronoi region of the host mobile body 10, walls and obstacles, a forgetting factor based on the position history of the host mobile body 10, the movement capability of the host mobile body 10, etc., and calculates the position where the potential of the modified local region is maximum as the target position for the next step.

For example, the potential value outside the Voronoi region of the player's mobile body 10 is corrected to be smaller, the potential value in the region of walls and obstacles is corrected to be smaller, the potential value in the part corresponding to the position history of the player's mobile body 10 is corrected to be larger, and the potential value outside the range that can be moved by the next step based on the movement capability of the player's mobile body 10 is corrected to be smaller.

Here, the route plan is assumed to be obtained from the control room, and the nearby route plan is obtained from the position information of the own mobile body 10. Note that the target position for the next step may be calculated using the potential gradient instead of the position where the potential is maximum.

The control device 14 repeats the processing of the movement information acquisition unit 30, the coverage area determination unit 32, and the movement control unit 34 at a predetermined control cycle until the host vehicle 10 reaches its final target position.

The operation of this embodiment will be explained below with reference to the flowcharts in Figures 6 and 7.

Figure 6 is a flowchart showing the distributed control routine executed by the distributed control program according to this embodiment, and shows a flow that is primarily focused on the movement control of the mobile object 10.

In step S100, the communication module 24 obtains a route plan from the control room to the final target position of the mobile unit 10.

In step S102, the position recognition module 22 acquires the position of the own mobile unit 10.

In step S104, the observation module 18 acquires position information of other mobile bodies 10 (their relative positions with respect to the host mobile body 10) and also acquires position information of walls and obstacles (their relative positions with respect to the host mobile body 10).

In step S106, the control device 14 calculates the target position for the next step.

In step S108, the control device 14 controls the movement module 20 to move the host vehicle 10 to the target position for the next step.

In step S110, the control device 14 determines whether the host vehicle 10 has reached the final target position. If the determination is affirmative, the routine ends. If the determination is negative in step S110, the process returns to step S102 and the above process is repeated.

Step S106 above is implemented by the processing routine shown in Figure 7.

First, in step S120, the coverage area determination unit 32 performs Voronoi division on the area 12 shown in Figure 2 above based on the position information of the other mobile body 10 obtained by the observation module 18, and determines the Voronoi areas as the coverage areas of the own mobile body 10 and the other mobile body 10.

In step S122, the movement information acquisition unit 30 acquires position information (relative positional relationship with the host vehicle 10) of walls and obstacles obtained by the observation module 18.

In step S124, the movement control unit 34 acquires the position history of the own mobile body 10.

In step S126, the movement control unit 34 acquires the movement capabilities of the player's own mobile object 10.

In step S128, the movement control unit 34 obtains a route plan near the current position from the route plan of the own mobile body 10.

In step S130, the movement control unit 34 calculates the potential of a local area including the position of the own mobile body 10 based on the route plan for the own mobile body 10.

In step S132, the movement control unit 34 modifies the potential of the local region based on the Voronoi region of the host mobile body 10, walls and obstacles, a forgetting factor based on the position history of the host mobile body 10, the movement capability of the host mobile body 10, etc.

In step S134, the movement control unit 34 calculates the position where the potential of the modified local region is maximized as the target position for the next step.

Figure 8 shows an example of five mobile units 10-1 to 10-5 passing through a T-junction simultaneously while avoiding collisions. The lines with arrows indicate the route plans for mobile units 10-1 to 10-5 provided by the control room.

Figures 9(A) to (F) show the positions of the five moving bodies 10-1 to 10-5 at each step. Figure 9(A) shows the positions of the five moving bodies 10-1 to 10-5 at the next step as of Figure 8, and Figure 9(B) shows the positions of the five moving bodies 10-1 to 10-5 at the next step as of Figure 9(A). Figure 9(C) shows the positions of the five moving bodies 10-1 to 10-5 at the next step as of Figure 9(B), showing moving body 10-4 having passed the intersection. Figure 9(D) shows the positions of the five moving bodies 10-1 to 10-5 at the next step as of Figure 9(C), showing moving body 10-5 having passed the intersection. Figure 9(E) shows the positions of the five moving bodies 10-1 to 10-5 at the next step as of Figure 9(D), showing moving body 10-3 having passed the intersection. Figure 9(F) shows the positions of the five moving bodies 10-1 to 10-5 in the next step at the time of Figure 9(E), with moving bodies 10-1 and 10-2 having just passed the intersection.

As described above, according to this embodiment, the potential of a local region including the position of the own mobile body is determined based on a route plan, a target position is calculated based on the potential of the local region and the Voronoi region of the own mobile body, and the own mobile body is moved to the target position, and this process is repeated. This allows multiple mobile bodies to move along their respective route plans while avoiding collisions under autonomous distributed control.

In addition, each moving object can sequentially revise its route plan and determine its target position using only its own information.

In addition, since there is no need to plan routes taking into account the number of moving objects, the number of moving objects can be changed flexibly.

In addition, each mobile unit can successively revise its route plan and determine its target position without communicating with nearby mobile units, allowing for completely autonomous and decentralized processing. Furthermore, each mobile unit does not need information about the route plans of nearby mobile units. Furthermore, there is almost no computational load on the control room.

Second Embodiment
Next, a distributed control system for a mobile object according to a second embodiment will be described. Note that the mobile object 10 according to the second embodiment has the same configuration as that of the first embodiment, and therefore the same reference numerals are used and the description thereof will be omitted.

The second embodiment differs from the first embodiment in that it calculates the target position for the next step based on the potential from within the Voronoi region of the host mobile body, without modifying the potential of the local region generated based on the path plan.

The movement control unit 34 of the control device 14 in the second embodiment sets a positive potential on the path plan within a local area centered on the current position of the host mobile body 10, and sets a negative potential on building walls, other mobile bodies 10, people, obstacles, etc. within the local area.

The movement control unit 34 then generates constraint conditions indicating the range within which the host mobile body 10 can move by the next step based on the Voronoi region of the host mobile body 10, walls and obstacles, a forgetting factor based on the position history of the host mobile body 10, the movement capability of the host mobile body 10, etc., and calculates the position within the range that satisfies the constraint conditions where the potential of the local region is maximized as the target position for the next step.

For example, the range of movement is set to the Voronoi region of the player's mobile unit 10, with areas of walls and obstacles excluded from the range of movement, parts corresponding to the position history of the player's mobile unit 10 included in the range of movement, and areas outside the range that can be moved to by the next step based on the movement capabilities of the player's mobile unit 10 excluded from the range of movement.

The control device 14 of the mobile unit 10 executes a routine similar to the distributed control routine shown in Figure 6 above.

Step S106 above is implemented by the processing routine shown in Figure 10.

First, in step S120, the coverage area determination unit 32 performs Voronoi division on the area 12 shown in Figure 2 above based on the position information of the other mobile body 10 obtained by the observation module 18, and determines the Voronoi areas as the coverage areas of the own mobile body 10 and the other mobile body 10.

In step S122, the movement information acquisition unit 30 acquires position information (relative positional relationship with the host vehicle 10) of walls and obstacles obtained by the observation module 18.

In step S124, the movement control unit 34 acquires the position history of the own mobile body 10.

In step S126, the movement control unit 34 acquires the movement capabilities of the player's own mobile object 10.

In step S200, the movement control unit 34 generates constraints indicating the range within which the host mobile body 10 can move, based on the Voronoi region of the host mobile body 10, walls and obstacles, a forgetting factor based on the position history of the host mobile body 10, the movement capability of the host mobile body 10, etc.

In step S128, the movement control unit 34 obtains a route plan near the current position from the route plan of the own mobile body 10.

In step S130, the movement control unit 34 calculates the potential of a local area including the position of the own mobile body 10 based on the route plan for the own mobile body 10.

In step S202, the movement control unit 34 calculates the position where the potential of the local region is maximized within the range that satisfies the constraints as the target position for the next step.

The other configurations and functions of the moving body 10 are the same as those in the first embodiment, so explanations will be omitted.

As described above, according to this embodiment, the potential of a local region including the position of the own mobile body is determined based on a route plan, a target position is calculated based on the potential of the local region and constraints that take into account the Voronoi region of the own mobile body, and the own mobile body is moved to the target position, and this process is repeated. This allows multiple mobile bodies to move along their respective route plans while avoiding collisions under autonomous distributed control.

[Third embodiment]
Next, a distributed control system for a mobile object according to a third embodiment will be described. Note that the mobile object 10 according to the third embodiment has the same configuration as that of the first embodiment, and therefore the same reference numerals are used and the description thereof will be omitted.

The third embodiment differs from the first embodiment in that the target position for the next step is calculated using a conventionally known method and compared with the target position for the next step calculated using the method described in the first or second embodiment above to determine the target position for the next step.

The movement control unit 34 of the control device 14 according to the third embodiment calculates the target position for the next step using the method described in the first or second embodiment above.

The movement control unit 34 also calculates the target position for the next step using a conventionally known method. For example, it calculates the target position for the next step according to the A-star algorithm based on the route plan for the host mobile unit 10 and the position information of other mobile units 10.

The movement control unit 34 calculates the distance between the target position for the next step calculated using the method described in the first or second embodiment above and the target position for the next step calculated using a conventionally known method, and if the distance is less than a threshold value, adopts the target position for the next step calculated using the conventionally known method, and if the distance is equal to or greater than the threshold value, adopts the target position for the next step calculated using the method described in the first or second embodiment above.

Figure 11 is a flowchart showing a distributed control routine according to the third embodiment, and shows a flow that is primarily specialized for controlling the movement of the mobile object 10. Note that processes similar to those in the first embodiment are assigned the same reference numerals and detailed explanations will be omitted.

In step S100, the communication module 24 obtains a route plan from the control room to the final target position of the mobile unit 10.

In step S102, the position recognition module 22 acquires the position of the own mobile unit 10.

In step S104, the observation module 18 acquires position information of other mobile units 10 as well as position information of walls and obstacles.

In step S106, the control device 14 calculates the target position for the next step.

In step S300, the movement control unit 34 calculates the target position for the next step using a conventionally known method.

In step S302, the movement control unit 34 calculates the distance between the target position for the next step calculated in step S106 above and the target position for the next step calculated in step S300 above. If the distance is less than a threshold, the target position for the next step calculated in step S300 above is adopted; if the distance is equal to or greater than the threshold, the target position for the next step calculated in step S106 above is adopted.

In step S108, the control device 14 controls the movement module 20 to move the host vehicle 10 to the target position for the next step.

In step S110, the control device 14 determines whether the host vehicle 10 has reached the final target position. If the determination is affirmative, the routine ends. If the determination is negative in step S110, the process returns to step S102 and the above process is repeated.

The other configurations and functions of the moving body 10 are the same as those in the first embodiment, so explanations will be omitted.

As described above, according to this embodiment, the potential of a local region including the position of the own mobile body is determined based on a route plan, a target position is calculated based on the potential of the local region and the Voronoi region of the own mobile body, the target position is calculated using a conventionally known method, and the target position for the next step is determined from the two target positions. This makes it possible to determine appropriate target positions for multiple mobile bodies to move along their respective route plans while avoiding collisions under autonomous distributed control.

The present invention is not limited to the above-described embodiments, and various modifications and applications are possible without departing from the spirit and scope of the invention.

For example, in the above embodiment, an example was described in which the target position for the next step was calculated, but this is not limited to this, and it is also possible to calculate the target position or trajectory several steps ahead.

In addition, while the above embodiment has been described with reference to an example in which no communication occurs between mobile bodies, this is not limited to this, and position information may be communicated between mobile bodies. In this case, position information may be communicated between mobile bodies at a period longer than the control period. This is because the observation module of each mobile body can obtain position information of other mobile bodies, and the performance of each mobile body's cruise control does not depend on communication.

Alternatively, people can be treated in the same way as nearby moving objects, and the Voronoi regions of people and moving objects can be calculated using Voronoi division. In this case, potentials can be set using Voronoi regions, taking into account collision avoidance with people.

The modification of the local area potential described in the first embodiment above may be combined with the generation of constraint conditions described in the second embodiment above. In this case, it may be possible to select whether to use the Voronoi region of the player's mobile body 10, walls and obstacles, a forgotten factor based on the position history of the player's mobile body 10, the movement ability of the player's mobile body 10, etc. to modify the local area potential or to generate constraint conditions.

10 Mobile body 14 Control device 18 Observation module 20 Movement module 22 Position recognition module 24 Communication module 30 Movement information acquisition unit 32 Coverage area determination unit 34 Movement control unit

Claims (5)

A control device in a distributed control system for mobile objects, comprising a plurality of mobile objects arranged in assigned areas that do not interfere with each other, and the plurality of mobile objects acquire position information from each other, thereby moving the plurality of mobile objects so as to change their assigned areas while avoiding collisions,
a movement information acquisition unit that acquires a route plan of the own moving body and position information of other moving bodies;
a coverage area determination unit that determines coverage areas of the own mobile body and the other mobile body based on the position information of the other mobile body;
a movement control unit that determines a potential of a local area including the position of the own mobile unit based on the route plan, the potential having a higher value as the collision risk decreases, calculates a target position based on the potential of the local area and the area covered by the own mobile unit, and moves the own mobile unit to the target position;
Including,
repeating the acquisition by the movement information acquisition unit, the determination by the coverage area determination unit, and the determination, calculation, and movement by the movement control unit at a predetermined cycle;
The movement control unit determines the potential of the local region according to a Gaussian distribution with a peak on the route plan, modifies the potential of the local region so that the value of the potential of the local region outside the area covered by the own mobile body becomes smaller, and calculates the position where the potential of the local region after the modification is maximum as the target position. The control device described in claim 1, wherein the movement information acquisition unit acquires position information of other mobile units using a sensor of the own mobile unit. A control device according to claim 1 or 2, wherein the area of responsibility is a Voronoi region surrounded by the perpendicular bisector between the moving objects. Computer,
A distributed control program for a moving object that operates as the control device according to any one of claims 1 to 3. A moving body comprising the control device according to any one of claims 1 to 3.