KR0151143B1 - Collision prevention method for mobile robot - Google Patents

Abstract

None.

Description

Collision Avoidance Method in Mobile Robot System

1 is a block diagram showing the configuration of a mobile robot system according to an embodiment of the present invention.

2 is a diagram showing an example of a traveling route on which each mobile robot travels.

3 is a block diagram showing the configuration of the control station 1 in FIG.

4 is a diagram showing a reserve table RVT set in the data memory le in FIG.

5 is an explanatory diagram for explaining a collision node in Table 1. FIG.

6 is an explanatory diagram for explaining a viewpoint collision node.

7 is a block diagram showing the configuration of the mobile robot 2.

* Explanation of symbols for main parts of the drawings

1: Control station 2-1 ~ 2-10: Mobile robot

S1, S2, S3, S4, Sa, Sb: Work points 1a, 2a: CPU (central processing unit)

1b, 2b: Program memory 1c: Conflict table

1d, 2f: Map memory 1e, 2c: Data memory

1f, 2d: Control panel 1g, 2e: Communication device

2g: travel control device 2h: arm control device

RVT: Reserve Table RV1 ~ RV14: Memory Slot

Na: viewpoint node Nb: endpoint node

Nk, N1: View point collision node Ee, Eg, Ei, Ek, Ep, Eq, Es: Exclusion area

The present invention relates to a mobile robot system composed of a plurality of mobile robots and a control station for controlling the mobile robots, and more particularly, to a collision preventing device for preventing collision between mobile robots.

In recent years, with the development of FA (Factory, Automation), this kind of system has been developed and put into practical use.

In this mobile robot system, the control station instructs each mobile robot by wire or by wire to perform the operation and the work to be performed at the destination.

The mobile robot instructed by the control station travels to the designated place, arrives, performs the indicated work at that place, and waits for the next instruction at the place when the work is finished.

However, in this kind of system, how to prevent collision between autonomous robots is a big problem.

If one robot is running and the other robot is stopped, the possibility of a collision can be made very small. However, the robot's running efficiency is very bad.

It is therefore an object of the present invention to provide a collision avoidance method in a mobile robot system in which a collision does not occur even when a plurality of mobile robots are driven on the same site.

The present invention provides a reservation table in a control station, and each mobile robot contacts the control station with a scheduled driving route, and the control station checks whether the scheduled driving route that has been contacted is already reserved by the reservation table. If all or part of the traveling route is not reserved, the reserved driving route is reserved in the reservation table, and the reservation end is notified to the mobile robot, and the mobile robot notifies the completion of the reservation. It is characterized in that the drive of the reserved running route is received.

According to the present invention, each mobile robot travels after reserving a travel route in the reservation table before traveling, and if the reservation is impossible, that is, if another mobile robot has already made a reservation, the route does not travel. By this, the mobile robot can completely prevent the collision between each other.

EXAMPLE

Hereinafter, a mobile robot system to which the collision prevention method according to an embodiment of the present invention is applied will be described with reference to the drawings.

1 is a block diagram showing the overall configuration of the mobile robot system.

In this figure, reference numeral 1 denotes a control station, and 2-1 to 2-10 are mobile robots, and the control station 1 and each of the mobile robots 2-1 to 2-10 are connected wirelessly. have.

The mobile robot 2 is moved along the magnetic tape attached to the bottom surface of the predetermined traveling path, and nodes are set on the traveling path at appropriate intervals.

2 is a diagram showing an example of a traveling path, in which 1, 2, 2 are nodes.

Each node is provided with a node mark on each bottom surface, and a detector for detecting the node mark is set in the mobile robot 2. In addition, there are three kinds of nodes.

(1) Leading node: This node is the starting point when the mobile robot 2 newly enters the road. In FIG. 2, it is ①, ⑤, ⑩, ⑭.

(2) Work node: A node in which work points S1, S2, and S3 are set. In FIG. 2,?,?,? When the mobile robot performs work, it stops once at this work node, and then proceeds to the work point S1 or S2 or S3 to stop the work.

(3) Passing node: The mobile robot is a node that simply passes, and in FIG. 2, all nodes other than the above node.

In addition, in the following description, the traveling path of FIG. 2 mentioned above is taken as an example.

3 is a block diagram showing the configuration of the control station 1, in which 1a is a CPU (central processing unit), 1b is a program memory in which a program used in the CPU 1a is stored; (1c) is a collision table described later. (1d) is the map memory, and the (XY) coordinates of each of the nodes ① to 에서 shown in FIG. 2, data indicating the type of the node, the number of the tannode connected to the node, and the node. The distances to the different nodes connected to each other are stored.

(1e) It is a data storage data memory, and a reserve table RVT shown in Fig. 4 is already provided in this data memory 1e.

This reserve table RVT has memory slots RV1 to RV14, one byte each corresponding to the nodes?

Reference numeral 1f denotes an operation unit, and 1g denotes a communication device. The communication device 1g loads and transmits data supplied from the CPU 1a on a carrier of 200-300MHZ, and also transfers the mobile robots 2-1 to 2-2. In step -10), the data transmitted on the carrier is received.

Here, the collision table 1c will be described. This collision table 1c is a table for preventing the collision between each mobile robot, and consists of a plurality of collision data blocks.

In this case, one block is formed in each collision data block corresponding to two adjacent nodes connected in the traveling path.

For example, in the case of the driving route of FIG. 2, the nodes (①, ②), (②, ③), (③, ④), (④, ⑤), (②, ⑥), (⑥, ⑦) A collision data block is formed for each of ----.

Table 1 (a) shows the structure of the collision table 1C, and (b) shows the structure of each collision data block.

Next, the collision data block will be described in detail.

For example, the collision data block corresponding to the node pairs ② and ③ may collide when the node ③ (or vice versa) moves the robot 2 from node ②, and if there are other robots in the node. The number of nodes that may be made and the number of such nodes are listed.

That is, as shown in Table 1 (b), the following data is written in the collision data block.

(1) Number and time of collision nodes

In FIG. 5, (Na) is a start node and (Nb) is an end node.

In addition, the start point and the end point only refer to one of two adjacent nodes as the start point and the other as the end point.

The viewpoint collision node is a node that may collide with this when the mobile robot 2 arrives at the viewpoint node Na (if the node has a mobile robot). It is a node existing in the exclusion area Es and a node within a predetermined range thereof.

Here, the exclusion region Es is, for example, as shown in FIG.

(W + 2α) × (L + 2α)

W: Width of Mobile Robot

L: length of mobile robot

α = 150 mm

It is an area of phosphorus size and is predetermined. In addition, since the node Nk indicated at the same level is in the exclusion area Es, the mobile robot 2 also has a dashed-dotted line as well as the viewpoint collision node or the node NL other than the exclusion area Es. In this case, since a part of it falls within the exclusion area Es, it is a viewpoint collision node.

The viewpoint node (Na) itself is also a viewpoint collision node.

As a result, in the example of FIG. 6, the numbers of the nodes Na, Nk, and NL and the number of nodes 3 are written in the collision data block, respectively.

(2) Number and number of endpoint collision nodes

An end point collision node is a node (when there is a mobile robot) which may collide with this when the mobile robot 2 arrives at the end node Nb of FIG. A node existing in the exclusion area Ee indicated by a broken line and a node within a predetermined range around the node. In addition, the meaning of a certain range is as described above.

(3) collision nodes between nodes and their number

The collision node between nodes is a node that may collide with this when the mobile robot 2 moves from the start node Na to the end node Nb (if there is a mobile robot in the node). ), Specifically, a node present in the exclusion area Ek indicated by a broken line and a node within a predetermined range around it.

(4) Reverse traveling collision nodes and their numbers

A reverse traveling collision node is a node that may collide with the robot when the robot moves from the end point to the start point when the robot detects the start point node Na and stops. A mobile robot) and a node existing in the exclusion area Ep shown in the drawing and a node within a predetermined range.

(5) Forward traveling collision nodes and their numbers

The forward traveling collision node is a node that may collide with this robot when the mobile robot traveling from the starting point to the end point brakes and stops when detecting the end node Nb (moves to the node). The presence of a robot, and the node existing in the exclusion area Eq shown in FIG.

(6) Crash nodes and their number

The point-of-view work collision node is a node (if there is a mobile robot) that may collide with it when the mobile robot 2 arrives at the work point Sa of FIG. A node existing in the exclusion area Eg indicated by a broken line and a node within a predetermined range around it.

(7) Endpoint work collision nodes and their number

The end work collision node is a node that may collide with this when the mobile robot 2 arrives at the work point Sb (when there is a mobile robot). A node existing in the exclusion area Ei and a node within a predetermined range thereof.

Note that not all of the data of (1) to (7) are always stored in the collision data block.

For example, work point collision nodes are not memorized, as well as when there are no work points at both the start and end points.

Next, the mobile robot 2 will be described.

7 is a block diagram showing the configuration of the mobile robot 2. In this figure, 2a is a CPU, 2b is a program memory in which a program used by the CPU 2a is stored, and 2d is an operation unit. And 2e are communication devices, 2f is a map memory in which the same data as the map memory 1d in the control station 1 is stored.

In addition, 2g is a traveling control device, receives driving data (travel data, traveling speed data, etc.) supplied from the CPU 2a, and controls the driving motor while detecting magnetic tape and node marks on the floor by a magnetic sensor. Move the robot to the destination node.

(2h) is an arm control device, receives a work program number supplied from the CPU 2a, reads the work program of that number from the internal memory at the time when the mobile robot arrives at the work node, The robot arm (not shown) is controlled to perform various operations.

Next, the operation of the above-described mobile robot system will be described.

First, in order to put the mobile robot 2 under the control of the control station 1, the mobile robot 2 is manually moved to any of the guidance entry nodes ①, ⑤, ⑩, and ,, and then the mobile robot 2 The node number is input on the operation unit 2d of the controller, and the signal is converted into an automatic motor.

When the node number is input, the CPU 2a posts the number and its own robot number to the control station 1 by displaying the communication device 2e.

The control station 1 receives the robot number and the node number and writes them into the data memory 1e.

By the above process, the control station 1 detects the number of the newly entered robot and its position.

Next, for example, when a job to be performed at the work point S1 occurs, the control station 1 displays a work point code for displaying the work point S1 for the mobile robot located at the position closest to the work point. Send the job program number.

It is assumed that the mobile robot 2-1 has stopped at the node ①, and the control station 1 has transmitted the work point code and program number to the robot 2-1.

The CPU 2a of the mobile robot 2-1 stores the received work point code and program number in the data memory 2c, and then searches for the running route to the work point S1. This route search is conventionally performed by a well-known vertical search method or the like.

Thus, if the route is found to be ① → ② → ③ → ④ by this route search, the CPU 2a continues to run the searched route based on the distance between nodes stored in the map memory 2f. The distance is accumulated sequentially from the starting point node ① to the target node ④, and the first node exceeding the predetermined predetermined distance X (see FIG. 2) is detected.

At this time, let this node be ③, and then the CPU 2a transmits the numbers of the nodes ①, ②, and ③ and the route reservation request code to the control station 1, respectively.

The CPU 1a of the control station 1 receives this node number and route reservation request code, and first of all, at the collision data block corresponding to the node groups 1 and 2 in the collision table 1c, a collision collision furnace is performed. Read nodes, endpoint collision nodes, collision nodes between nodes, and forward traveling collision nodes.

Next, the reserve table RVT checks whether these nodes are already reserved.

Thus, if not reserved, i.e., if the data in the memory slots RV1 to RV14 corresponding to these nodes in the reserve table RVT becomes (0), the robot number (1) is assigned to their storage slots, respectively. Fill in.

By these, routes ① → ② are reserved.

Next, the CPU 1a of the control station 1, as in the above, starts at the collision data block corresponding to the node pairs ② and ③ in the collision table 1c. The collision node and the forward traveling collision node are read, and it is checked whether these nodes are already reserved. Thus, if not reserved, the robot number 1 is written into the memory slots RV1 to RV14 of the collision table 1c corresponding to those nodes, respectively. Thereby, route ② → ③ is reserved.

When the route reservation is made in this manner, the CPU 1a next transmits the numbers of the nodes 1 to 3 and the reserved code to the mobile robot 2-1.

The mobile robot 2-1 receives these node numbers and a reserved code, and first starts traveling toward the node ②.

When the predetermined time elapses, the mobile robot 2-1 transmits to the control station 1 data indicating the current state of the robot (traveling, waiting, working, etc.) and the current position.

The control station 1 always checks the current position data sent from the mobile robot 2-1, and releases the reservation of routes 1 & cir & ② when the mobile robot 2-1 passes through the node ②. That is, the robot number 1 written in the reserve table RVT is changed to (0) at the time of reservation of the route (1) to (2).

On the other hand, the mobile robot 2-1 always detects the first node that exceeds the distance X from the current position to the target node while driving, and when the detected node becomes ④, the node ③, The number (4) and route reservation request code are transmitted to the control station 1, respectively.

The control station 1 receives this node number and route reservation request code, and makes a node reservation based on the data in the collision data blocks corresponding to the node groups 3 and 4 in the collision table 1c.

Thus, when the node reservation is completed, the number of nodes 3 and 4 and the reservation completion code are transmitted to the mobile robot 2-1.

The mobile robot 2-1 receives these node numbers and reservation completion codes, and travels to the node ④.

When the mobile robot 2-1 passes through the node ③, the control station 1 cancels the reservation of the route ② → ③ in the same manner as in the case described above. Thus, when the node ④ has been reached, the process proceeds to the work point S1 by the following traverse (proceeding in the transverse direction).

When the mobile robot 2-1 reaches the work point S1, the reservation cancellation of the route 3 < 4 > is performed.

In this case, however, only the end work collision node is not cancelled.

Next, in the above process, for example, it is possible to make a reservation from node ③, but not from route ③ to ④.

This occurs, for example, when the mobile robot 2-k traveling from nodes (5) to (4) (8) has previously reserved the route.

In this case, the mobile robot 2-1 stops at the time when the node 3 passes through the node ③, and repeatedly transmits the route reservation request code to the control station 1 while waiting.

When the mobile robot 2-k passes through the route ④ → ⑧, the control station 1 cancels the reservation of the route ④ → ⑧ and then continues to the route ③ → ④ requested by the mobile robot 2-1. Make a reservation.

As a result, the mobile robot 2-1 can proceed.

In addition, when the reservation request of the route ① → ② → ③ is made, only the reservation of the route ① → ② is made, and the reservation of the route ② → ③ is not possible, the control station 1 moves the reservation completion of the route ① → ② to the mobile robot. Contact (2-1). In this case, the mobile robot 2-1 starts to travel the routes 1 & cir & ②, and makes a reservation request after the node 3 >

Thus, in this mobile robot system, the reserve table RVT is provided in the control station 1, and each mobile robot 2 runs, making a reservation to this reserve table RVT.

Therefore, when the mobile robot 2 is in the scheduled driving route or when the mobile robot attempts to enter the scheduled driving route in advance, it is impossible to make a route reservation. There is no risk of collision.

Further, in the above embodiment, the mobile robot travels along the tape while detecting the magnetic tape on the floor, but the present invention can also be applied to the mobile robot traveling while detecting the surrounding situation by the ultrasonic sensor.

Further, in the above embodiment, the mobile robot has an arm, but the present invention can also be applied to a mobile robot (for transportation, etc.) that does not have an arm and merely travels.

As described above, according to the present invention, a reservation table is provided in the control station, and each mobile robot contacts the control station with a reserved driving route, and the control station has already reserved the scheduled driving route that has been contacted. If all or part of the traveling route is not reserved, the reserved table is reserved for the non-reserved traveling route, and the end of the reservation is notified to the mobile robot. Since the mobile robot is informed of the completion of the reservation, the mobile robot is allowed to travel the reserved driving route, and thus the mobile robot can efficiently run without colliding the plurality of mobile robots.

Claims (1)

A plurality of mobile robots, a control station for controlling these mobile robots, and a communication device for communicating between the mobile robots and the control station, wherein each mobile robot travels while detecting a node mark installed on the travel path. In the robot system, a reservation table installed in the control station, a transmission means for contacting the control lookup with the scheduled running route of the respective mobile robots, and whether the scheduled running route that the control station has been contacted with are already reserved. A reservation means for retrieving the searching means searched by the reservation table and a traveling route not reserved if a part or all of the traveling route is not reserved in the reservation table and then contacting the mobile robot for the type of reservation. The completion means and the mobile robot are informed of the completion of the reservation, and the reservation driving for driving the reserved driving route is completed. Collision prevention method in the mobile robot system comprising the features, however, the.

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