JP2814578B2 - Travel control method for mobile robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] In the present invention, a mobile robot can no longer run in a mobile robot system including a plurality of mobile robots and a control station that controls these mobile robots. In this case, the present invention relates to a travel control method for a mobile robot that searches for a detour route and enables detour.

[Prior Art] In recent years, with the development of factory automation (FA), various mobile robot systems including a plurality of mobile robots and a control station that controls these mobile robots have been developed and put into practical use.

In this mobile robot system, the control station instructs each mobile robot to a destination and an operation to be performed at the destination by radio or wire. The mobile robot, which receives instructions from the control station, looks at the map information, automatically travels to the designated location, reaches the designated location, performs the designated task at that location, and when the work is completed, the next Wait for instructions.

[Problems to be Solved by the Invention] In this type of conventional system, when a mobile robot that travels automatically has another mobile robot ahead of the travel route, the mobile robot waits until the other mobile robot disappears. I was In this case, if the other mobile robot is operating normally, it will leave there soon, so there is no problem, but if the other mobile robot is stopped due to a failure, it is waited for a considerable time, Had been a problem. To solve this problem, a detour method is conceivable.However, during the detour, a new detour cause may occur.In such a case, the target value is always set. It will be impossible to reach.

The present invention has been made in view of such circumstances, and has as its object to provide a traveling control method for a mobile robot that ensures smooth traveling during a detour.

Means for Solving the Problems The present invention comprises a plurality of mobile robots and a control station that controls these mobile robots, and the mobile robot performs a route search based on map information, and In a mobile robot system that travels while making a reservation to the control station, each mobile robot
The control station notifies the control station of position data indicating the current position and state data indicating the current state, and the control station stores the position data and the state data of the other mobile robots in each mobile robot so that the mobile robot can travel. If the mobile robot disappears, the mobile robot refers to the position data and state data of the other mobile robot to detect the cause of the inability to travel, and determines whether to perform a detour based on the cause, When it is determined that it is necessary to perform the detour route, the detour route is searched, the route is reserved for the entire range of the detour route searched, and then the detour route is traveled.

According to the present invention, when the cause of the detour occurs on the traveling route of the mobile robot, the mobile robot does not enter the detour route unless all reservations for the detour route are completed. In addition, smooth running during detour can be ensured.

Hereinafter, a mobile robot system to which a traveling control method according to an embodiment of the present invention is applied will be described with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of the mobile robot system. In this figure, 1 is a control station, 2
(2-1 to 2-10) are mobile robots, and the control station 1 and each mobile robot 2 are wirelessly connected. The mobile robot 2 travels along a magnetic tape attached to a floor of a predetermined traveling path, and nodes are set on the traveling path at appropriate intervals. Here, the nodes are start point, stop point, branch point,
It is a traveling state change point provided on the traveling path such as a work point. FIG. 2 is a diagram showing an example of a traveling route, in which nodes in FIG. Each node has a node mark attached to the floor, and the mobile robot 2 is provided with a detector for detecting the node mark. Nodes are classified into the following three types according to the locations where the nodes are installed.

(1) Map entry node: This is a node serving as a starting point when the mobile robot 2 newly enters the travel path. In FIG.

(2) work node: a node provided at a work point,
In FIG. 2, they are.

(3) Passing nodes: nodes that the mobile robot 2 simply passes through, and in FIG. 2, all nodes other than the above-described nodes.

Note that nodes other than the passing nodes are also called stations.

FIG. 3 is a block diagram showing the configuration of the control station 1. In this figure, 1a is a CPU (central processing unit), and 1b is a CPU 1a.
Is a program memory in which a program used in is stored, and 1c is a collision table in which data for preventing collision between the mobile robots 2 is stored. 1d is a map memory, including XY coordinates of each node shown in FIG. 2, data indicating a node type, numbers of other nodes connected to the node, and other nodes connected to the node. Is stored. Reference numeral 1e denotes a data memory for storing data. The data memory 1e is provided with a reserve table RVT shown in FIG. 4 in advance. The reserve table RVT has storage slots RV1 to RV18 (one byte each) corresponding to the nodes 〜. 1f is an operation unit, 1g is a communication device, this communication device
1g transmits the data supplied from the CPU 1a on a carrier wave of 200 to 300 MHz, and receives data transmitted from the mobile robot 2 on a carrier wave.

Next, the mobile robot 2 will be described. FIG. 5 is a block diagram showing the configuration of the mobile robot 2. In this figure, 2a is a CPU, 2b is a program memory storing programs used in the CPU 2a, 2c is a data memory for storing data, and 2d is an operation. Reference numeral 2e denotes a communication device, and 2f denotes a map memory storing the same data as the map memory 1d in the control station 1. Reference numeral 2g denotes a travel control device which receives destination data supplied from the CPU 2a, controls a drive motor while detecting a magnetic tape and a node mark on the floor surface by a magnetic sensor, and causes the mobile robot 2 to travel to a target node. . Reference numeral 2h denotes an arm control device, which receives a work program number supplied from the CPU 2a, reads a work program of that number from an internal memory when the mobile robot arrives at a work node, and reads the work program of the robot arm (not shown in the figure) by the read program. ) To perform various operations.

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

First, in order to place the mobile robot 2 under the control of the control station 1, the mobile robot 2 is manually moved to the map entry node,
,,, And then, input the number of the node from the operation unit 2d of the mobile robot 2 and switch to the automatic mode. When the node number is input, the CPU 2a sends the node number and its own robot number to the control station 1 via the communication device 2e. The control station 1 receives the robot number and the node number, and
Write in 1e. Through the above process, the control station 1 detects the number of the newly entered mobile robot 2 and its position.

Next, for example, when a work to be performed at a work node (station) occurs, the control station 1 sends a work point code and a work program number indicating the work node to the mobile robot 2 located closest to the work node. Send. Now, it is assumed that the mobile robot 2-1 has stopped at the node, and the control station 1 has transmitted a work node code and a program number to the mobile robot 2-1. The CPU 2a of the mobile robot 2-1 stores the received work node code and program number in the data memory 2c, and then searches for a traveling route to the work node. This route search is performed by a conventionally known vertical search method or the like. Then, if this route search finds a route of →→→→
Next, the CPU 2a creates the route table ROT shown in FIG. 6 in the data memory 2c, and creates the route table ROT.
The ROT is transmitted to the control station 1.

In this route table ROT, as shown in the figure, the numbers “2”, “3”, “3” of the starting node number “1” and the nodes that should be sequentially passed to the target work node 4 ", a work code" 65000 "indicating that the following data is work-related data, a work node number" 5 ", a work program number" 12 ", and that the following data represents the final posture of the robot. The final attitude code “65001”, the number of the node to be stopped “5”, the number of the front node “6”, the number of the rear node “4”, and the last code “0” representing the end of the route table ROT are written. It is.

The control station 1 writes the route table ROT in the internal data memory 1e, and then transmits the table ROT to the other mobile robots 2-2 to 2-10. The other mobile robots 2-2 to 2-10 write the same table ROT in the internal data memory 2c. Next, the mobile robot 2-1
Based on the distance between the nodes stored in the map memory 2f, the mileage of the searched route is sequentially accumulated from the starting point node to the destination node, and the first mileage exceeding the predetermined distance L is calculated. Discover nodes. Suppose that this node is now. Next, CPU2a is a node,
And the route reservation request code are transmitted to the control station 1. The CPU 1a of the control station 1 receives the node number and the route reservation request code, and checks whether or not these nodes are already reserved by using the reserve table RVT. If the data is not reserved, that is, if the data in the storage slots RV1 to RV3 corresponding to these nodes in the reserve table RVT is “0”, a robot number “1” is assigned to each of those storage slots. Write. Thus, the route →→ has been reserved. Next, the CPU 1a of the control station 1 transmits the number of the node and the reservation completion code to the mobile robot 2-1. The mobile robot 2-1 receives the node number and the reservation completion code, and starts traveling toward the node. The mobile robot 2-1 transmits state data and position data to the control station 1 every time a predetermined time elapses during traveling. Here, the state data is data indicating the current state of the mobile robot 2 (running, waiting, working, abnormal, etc.), and the position data indicates the current position of the mobile robot 2. It is data. The control station 1 transmits the state data and the position data sent from the mobile robot 2-1 and the reservation node data indicating the node currently reserved by the mobile robot 2-1 to the other mobile robots 2-2 to 2-2. Send to -10. These mobile robots 2-2 to 2-10 write the received data to the internal data memory 2c. Further, the control station 1 checks the position data transmitted from the mobile robot 2-1 and, when detecting that the mobile robot 2-1 has passed the node and subsequently passed the node, releases the reservation of the node following the node. I do. That is, the storage slots RV1 to RV2 of the reserve table RVT are cleared. On the other hand, mobile robot 2-
1 always detects the first node exceeding the distance L from the current position to the destination node during traveling, and when the detected node becomes, the node number and the route reservation request code are respectively set to the control station. Send to 1. The control station 1 receives the node number and the route reservation request code, and makes a node reservation. Then, when the node reservation is completed, the node number and the reservation completion code are transmitted to the mobile robot 2-1. The mobile robot 2-1 receives the node number and the reservation completion code, and travels to the node. When the mobile robot 2-1 passes through the node, the reservation of the node is canceled in the control station 1 in the same manner as described above. On the other hand, while traveling to the node →, the mobile robot 2-1
When the work node is detected as the first node exceeding the distance L from the current position to the destination node, the work node number and the route reservation request code are respectively set to the control station 1
Send to The control station 1 receives the node number and the route reservation request code, and makes a node reservation. Then, when the node reservation is completed, the work node number and the reservation completion code are transmitted to the mobile robot 2-1. The mobile robot 2-1 receives these node numbers and the reservation completion code, and travels to the work node. When the mobile robot 2-1 passes through the node, the reservation of the node is canceled in the control station 1 in the same manner as described above. Then, when reaching the work node, work by the arm is performed thereafter. As described above, the mobile robot 2-1 performs the route table ROT prior to the start of traveling.
Is transmitted to the control station 1, and state data and position data are sequentially transmitted to the control station 1 during traveling. Control station 1
Stores the transmitted route table ROT, state data, and position data in the data memory 1e, and transmits the table, data, and reserved node data to all the mobile robots 2. Other mobile robots 2-2 to 2-
Exactly the same processing is performed when the vehicle 10 runs. Therefore, in this mobile robot system, each mobile robot 2 has a route table of another mobile robot 2,
State data, position data, and reserved node data are held in the internal data memory 2c. Thereby, each mobile robot 2 can always detect the traveling route of the other mobile robot 2 and the current state, current position, and reserved node.

Next, a description will be given of a process in the case where the mobile robot 2-1 travels according to the route table ROT shown in FIG.

For example, when the mobile robot 2-1 reaches the node, if the node has not been reserved yet, the mobile robot 2-1 temporarily stops at the node and performs the next processing.

(1) First, the route table ROT of the other mobile robots 2-2 to 2-10 stored in the data memory 2c is scanned to detect the mobile robot 2 having the node as a part of the travel route. Now, mobile robots 2-3 and 2-
Suppose that 5 was applicable.

(2) Next, the mobile robot 2 that has reserved the node is detected from each reserved node data of the mobile robots 2-3 and 2-5 stored in the data memory 2c. Now, it is assumed that the mobile robot 2-3 has been detected.

(3) Next, the state of the mobile robot 2-3 is detected from the state data of the mobile robot 2-3 stored in the data memory 2c, and the following processing is performed according to the state. .

(I) When the mobile robot 2-3 is on standby The mobile robot 2-1 transmits its state data to the control station 1 as "waiting for completion of eviction". The control station 1 receives the state data and receives the route data of each of the mobile robots 2-2 to 2-10 stored in the internal data memory 1e.
The mobile robot 2-3 on standby is found based on the ROT and the position data, and a path transfer instruction and a destination node instruction are transmitted to the mobile robot 2-3. The mobile robot 2-3 that has received the route transfer instruction performs a route search to the designated node, makes a route reservation, and travels to that node in the same manner as described above. When the mobile robot 2-3 moves, the reservation of the node is released. On the other hand, the mobile robot 2-1 transmits the state data to the control station 1 as “waiting for completion of eviction”, and then transmits a travel path reservation request to the control station 1 every elapse of a predetermined time. When the mobile robot 2-3 moves and the node reservation is released, the control station 1 makes a reservation for the mobile robot 2-1 and transmits a reservation completion to the mobile robot 2-1. Upon receiving the reservation completion, the mobile robot 2-1 starts running. If a re-route search instruction is sent from the control station 1 while the travel route reservation request is issued, a route search is performed, and the vehicle travels with a different course.

(Ii) When the mobile robot 2-3 is traveling toward the node The mobile robot 2-1 sends status data to the control station 1 as "waiting for passage", and thereafter issues a travel path reservation request every elapse of a predetermined time. Waiting for reservation completion while sending to control station 1. In addition,
When an abnormality occurs in the mobile robot 2-3 that is going to pass, a detour route search described in the next section (iii) is performed, and the mobile robot changes traveling route.

(Iii) When an abnormality is occurring The mobile robot 2-1 performs a re-route search. That is, the mobile robot 2-1 first sends a route search permission request to the control station 1. The control station 1 receives this request, and sends a route search permission to the mobile robot 2-1 when there is no other mobile robot 2 currently searching for a route. Mobile robot 2-
1 receives this route search permission and searches for a route that bypasses the mobile robot 2-3. When the route is found, the mobile robot 2-3 is executed in the same manner as described above.
CPU 2a creates the route table ROT shown in FIG. 7 in the data memory 2c and creates the created route table ROT.
T is transmitted to the control station 1.

As shown in the figure, the route table ROT has a detour start code “65003” indicating the detour start, a departure start node number “8”, nodes “9” and “10” to be sequentially passed, and a detour end. Detour end code `` 6500
"4", the detour end node number "4", the work code "65000" indicating the work instruction, the work node number "5", the work program number "10" indicating the work program, and the following data are the mobile robot 2 data. The final attitude code "65001" indicating the final attitude, the node number "5" to stop, the node number "6" in the front node, the node number "4" in the rear node, and the final number indicating the end of the route table ROT. Code "0" is written. The control station 1 transmits the route table ROT to the other mobile robots 2-2 to 2-10. Next, the CPU 2a of the mobile robot 2-1 transmits to the control station 1 the numbers of all the nodes existing between the detour start node and the detour end node and the route reservation request code. As described above, the reservation request in the detour route is simultaneously made to all the nodes in the detour route, which is different from the above-described case where the reservation request for the normal traveling route is made. CPU1a of control station 1
Receives the node numbers and the route reservation request codes of all the nodes in the bypass route, and checks whether or not these nodes are already reserved by using the reserve table RVT. Then, for a node that is not reserved, the number “1” of the mobile robot 2-1 is written into the corresponding storage slot of the reserve table. On the other hand, if there is at least one node that has already been reserved by another mobile robot 2, it waits until the reservation of that node is released. When the reservation of all the nodes for which the reservation is requested is completed, the control station 1 transmits a reservation completion code to the mobile robot 2-1. The mobile robot 2-1 starts running upon receiving the reservation completion from the control station 1. Then, the vehicle travels on the detour route according to the route table ROT shown in FIG.
The work is performed according to the work procedure indicated by "0".

(Iv) When the conflict problem is being resolved This conflict problem is being resolved when the mobile robot 2-3 is
This is the case where the status is "waiting for completion of eviction", "waiting for work completion", "waiting for passage", "waiting for recovery from abnormality", or the like.
In this case, the mobile robot 2-1 sends the state data to the control station 1 as “waiting for a conflict solution”, and
Wait for problem-3.

As described above, each of the mobile robots 2-1 to 2-10 in the mobile robot system starts the detour after the reservation of the entire range of the detour route is completed when the detour is performed. Thus, it is possible to prevent a new detour cause from occurring. Thereby, running confusion at the time of detour can be prevented.

In the above embodiment, the mobile robot runs along the tape while detecting the magnetic tape on the floor.
The present invention can also be applied to a mobile robot that travels while detecting the surrounding situation with an ultrasonic sensor. In the above embodiment, the mobile robot has an arm. However, the present invention can be applied to a mobile robot that does not have an arm and simply runs automatically (for transportation, etc.).

[Effects of the Invention] As described above, according to the present invention, it is possible to prevent a new cause of detour from occurring during detour driving, and thus it is possible to prevent running confusion during detour.
As a result, smoother operation of the mobile robot system as a whole can be achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a mobile robot system according to an embodiment of the present invention, FIG. 2 is a diagram showing an example of a traveling path on which each mobile robot travels, and FIG. 3 is a control station 1 in FIG. FIG. 4 is a diagram showing a reserve table RVT set in the data memory 1e in FIG. 3, FIG. 5 is a block diagram showing a configuration of the mobile robot 2, and FIG. FIG. 7 is a diagram showing a configuration example of a table ROT, and FIG. 7 is a diagram showing a configuration example of a route table ROT at the time of detour. 1 ... Control station, 1a ... CPU, 1b ... Program memory, 1
e: Data memory, 2-1 to 2-10: Mobile robot, 2a: CPU, 2b: Program memory, 2c: Data memory.

Claims (1)

(57) [Claims] 1. A mobile robot comprising: a plurality of mobile robots; and a control station for controlling the mobile robots. The mobile robot searches for a route based on map information and travels while reserving the route to the control station. In each of the mobile robot systems, each mobile robot notifies the control station of position data indicating a current position and state data indicating a current state at predetermined time intervals. The position data and state data of the mobile robot are stored, and when the mobile robot cannot run, the cause of the mobile robot being unable to run with reference to the position data and state data of the other mobile robot is detected, It is determined whether or not to make a detour based on the cause, and when it is determined that the detour should be made, a detour route is searched and After route reservation for the complete range of the alternate route has, travel control method for a mobile robot, which comprises running the bypass route.