JPS63150710A - Method for evading collision in autonomous unmanned vehicle system - Google Patents

Abstract

PURPOSE:To evade the collision of unmanned vehicles in advance entirely in dependently of a central station by deciding the operation to evade the collision and executing it while the information are being exchanged between unmanned vehicles having a possibility of collision. CONSTITUTION:Other vehicle detectors 7A, 7B detecting the access of other vehicle and a communication equipment 3 as a communication means exchanging the information mutually to the unmanned vehicles 1A, 1B are provided respectively. At first, when the unmanned vehicle 1A detects the access of the unmanned vehicle 1B, its own identification number and the information relating to the present position and the traveling direction are sent to the vehicle 1B. On the other hand, the vehicle 1B discriminates the presence of the danger of collision based on the sent information and the vehicle 1B discriminating the presence of the danger of collision replies the information relating to its own identification number, present position and traveling direction. Then the unmanned vehicle of the master side decides the evading and executes it mutually. Thus, the collision of the unmanned vehicle is evaded entirely independently of the central station 2.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention enables a plurality of self-contained unmanned vehicles to recognize their current positions and move to a work point where a work request has occurred, relying on built-in map information. In a mobile autonomous unmanned vehicle system,
The present invention relates to a collision avoidance method that can prevent collisions between autonomous unmanned vehicles.

[Conventional technology] Currently, autonomous unmanned vehicles are being actively developed.
As shown in Fig. 6, this type of unmanned vehicle system includes a plurality of unmanned vehicles A, B, etc., and these unmanned vehicles A, B,
A typical example is one consisting of one central station C that centrally controls... Then, the three unmanned vehicles A, B, ... follow the instructions from the central station C, travel to the work point where the work request occurred via each node (point a) Nl-N9, and perform the required work. conduct. Central station C manages the map information of the movement area of unmanned vehicles A, B, etc., and also manages the map information of the movement area of unmanned vehicles A, B, etc.
It monitors the current position of B,... and whether it is working or not, and communicates with each unmanned vehicle A, B,... by communication means such as wireless.
Give work instructions while communicating with the staff.

For example, as shown in FIG. 6, when a work request occurs at a work point located at node N9, the central office C selects the best unmanned vehicle to go to node N9 from among the unmanned vehicles that are not currently performing work. Search for. Here, unmanned vehicle A is at node N1
If the unmanned vehicle A is waiting between node N2 and N2, a command is given to the unmanned vehicle A to go to node N9. Then,
Unmanned vehicle A locates node N based on its own built-in map information.
9, for example, node N2-N3→N
6→N9 route is determined. The vehicle then travels along this route to node N9 while recognizing its current location and relying on the built-in map information.

: Problems to be solved by the invention By the way, in the above-mentioned autonomous unmanned vehicle system,
The central station C only specifies the node to which each unmanned vehicle A, B, etc. should go, and as for the travel route,
Each unmanned vehicle A, B, . . . determines independently. The reason for this is that the central station C was searching for routes to the nodes to which all unmanned vehicles A, B, etc. that are not currently working are headed. A, B,
This is because the search time decreases in proportion to the number of devices, making it impossible to perform quick processing. However, the central station C does not manage the driving routes of each unmanned vehicle A, B, . . .

In the method that B,... decides independently, in some way,
Collisions between unmanned vehicles must be avoided.

For example, as shown in FIG.
If there is an unmanned vehicle B traveling on the route of , and unmanned vehicle A starts traveling on the route of nodes N 2-N 5-N 6-N 9, both of them will be traveling between nodes N2 and N5. This will result in a collision.

This invention was made against this background, and provides a collision avoidance method in an autonomous unmanned vehicle system that can prevent collisions between autonomous unmanned vehicles without relying on a central station at all. The purpose is to provide

[Means for Solving the Problems] In order to solve the above problems, the present invention provides each unmanned vehicle with:
A communication means for mutually exchanging information and a detection means for detecting the approach of another unmanned vehicle are provided, and when each of the unmanned vehicles detects the approach of another unmanned vehicle by the detection means, While information regarding its own identification number, current location, and driving direction is transmitted to all unmanned vehicles via the communication means, each unmanned vehicle determines whether there is a risk of collision based on the transmitted information. An unmanned vehicle that has determined that there is a risk of collision will respond via the communication means with information regarding its own identification number, current location, and direction of travel, and will thereafter determine whether there is a risk of collision. The system is characterized by the fact that unmanned vehicles exchange information, decide on actions to avoid a collision, and mutually execute the actions.

[Function] According to the above configuration, when a risk of collision occurs, unmanned vehicles that may be involved in the collision exchange necessary information with each other, thereby allowing the unmanned vehicles to avoid the collision by themselves. Execute the action.

Therefore, collisions between unmanned vehicles can be avoided without depending on the central station at all.

[Example code] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In this embodiment, in order to simplify the explanation, an autonomous unmanned vehicle system consisting of two unmanned vehicles IA and IB (hereinafter abbreviated as A vehicle and B vehicle) and a central station 2 will be described. Let me explain using an example.

In FIG. 1, the central station 2 is a CPU (central processing unit)
It consists of , memory, communication equipment, etc.
The status of the car and Car B is always known, such as the current location and whether or not work is underway. It is also connected to each work point, accepts work requests from the work points, and transmits this information to cars A and B by radio.

Car A and car B are composed of a communication device 3, a command section 4, a running section 5, a map memory 6, and an other vehicle detector 7A (7B). Further, the running unit 5 includes a running control unit 8,
Left and right drive wheels 9L and 9R, and a motor IOL that rotationally drives the left and right drive wheels 9L and 9R, respectively.

10R, pulse encoders IIL and IIR that detect the rotational speed of the left and right drive wheels 9L and 9R, respectively, and transmitter/receivers 12L and 12R that emit ultrasonic waves toward the left and right and receive the ultrasonic waves reflected from the left and right side walls. , an ultrasonic distance measuring section 13 that measures the distance to the left and right side walls based on the ultrasonic propagation time, and a trajectory correction section 14.

The map memory 6 stores in advance map data regarding the coordinates of each node, the distance from the travel route connecting each node to the left and right side walls, and the like.

In addition, the trajectory correction unit 14 compares the distance measurement data obtained from the ultrasonic distance measurement unit 13 and the map data read from the map memory 6 point by point, and uses the correction data to control the travel based on the comparison result. 8.

The travel control unit 8 normally uses a travel command (consisting of travel distance, speed, rotation angle, node number to be reached after travel, etc.) instructed by the command unit 4 to create a system suitable for the form of its own travel device. A travel pattern (trajectory pattern and speed pattern such as straight travel and curves) is created, and the rotations of the left and right drive wheels 9L and 9R are respectively controlled based on this travel pattern and correction data. Furthermore, when a travel control command is directly supplied from the command unit 4 during a collision avoidance operation to be described later, the travel control unit 8 executes this command with priority. In this case, unlike usual, the driving control unit 8 controls the rotation of the drive wheels 9L and 9R as instructed by the command unit 4, so that the command unit 4 directly controls the driving. Become.

Other vehicle detectors 7A and 7B mounted on cars A and B respectively include a transmitter that emits omnidirectional identification radio waves of a predetermined frequency (for example, about 100 kHz), and a transmitter that emits omnidirectional identification radio waves of a predetermined frequency (for example, about 100 kHz), and a transmitter that emits omnidirectional identification radio waves of a predetermined frequency (for example, about 100 kHz), and a transmitter that emits omnidirectional identification radio waves of a predetermined frequency (for example, about 100 kHz), and a transmitter that emits omnidirectional identification radio waves of a predetermined frequency (for example, about 100 kHz). As shown in Figure 3, the transmitter and receiver are operated alternately, and the receiver receives the identification radio waves. and a detection circuit that outputs a detection signal when detected. In this case, the transmission period TA during which the transmitter on the other vehicle detector 7A side operates and the reception period RA during which the receiver operates are the same as the transmission period TB during which the transmitter on the other vehicle detector 7B side operates and the receiver operates. Reception period RB
and are appropriately set to be different from each other. As a result, as shown in FIG. 2, when vehicles A and B approach within the detection range of radius ra or rb, other vehicle detectors 7A and
B detects identification radio waves emitted by the other party, and supplies a detection signal to the command unit 4. The detection range of the radii ra and rb above varies slightly depending on the output of each transmitter and the sensitivity adjustment of each receiver, but is approximately 3 m.
It is set to about.

On the other hand, the command unit 4 is wirelessly connected to the central station 2 and the command unit 4 of another vehicle via the communication device 3, and exchanges various information using a polling/selecting method. When the command unit 4 is instructed from the central station 2 to the node of the work point where the work request has occurred, the command unit 4 refers to the map data stored in the map memory 6 and searches for an optimal travel route.
Determine which nodes to pass through on the way to the destination node.

Further, travel commands are sequentially created and given to the travel unit 5 so that the robot moves along the travel route connecting each determined node. Further, when a detection signal is supplied from the other vehicle detector 7A (7B), the command unit 4 starts a collision avoidance operation to be described later, directly gives a travel control command to the travel unit 5, and sends a driving wheel 9L, 9R. Directly control the rotation of

Next, an explanation will be given of the operation in the above-described embodiment when cars A and B approach each other between nodes N2 and N5 while facing each other, as shown in FIG.

First, at time T1 shown in FIG. 3, the other vehicle detector 7A of vehicle A first detects the other vehicle (in this case, since there are two systems, the other vehicle will inevitably be vehicle B, or In the case of three or more vehicles, it is assumed that an identification radio wave of an unspecified vehicle is detected and a detection signal is output to the command unit 4. Then, the command unit 4 of car A starts collision avoidance operation.

Hereinafter, with reference to the flowchart shown in FIG. 4, the collision avoidance operation of car A will be explained in relation to the collision avoidance operation of car B.

First, when car A detects the approach of another car, step SAI
Then, the process proceeds to step SA2, and the command unit 4 of car A communicates with the traveling unit 5
A direct travel control command is given to the vehicle A to stop, and as a result, vehicle A temporarily stops. Next, the communication device 3 notifies that the other vehicle has been detected, along with information consisting of the own military's identification code (vehicle number), the current position, and the next node number.
(Step 5A3).

On the other hand, the other vehicle, vehicle B, stops once it receives the information transmitted by vehicle A (step 5DI), and based on the information transmitted by vehicle A, the current position of its own army, and the next node number to arrive at. Step 582). If it is determined that there is a risk of collision, proceed to step SB3. If it is determined that there is no risk of collision, proceed to step SB3. Proceed to step SB6. In step SB3, vehicle B transmits information consisting of its own army's identification code, current position, and next arriving node number to vehicle A. Next, based on the information received from vehicle A earlier, vehicle -B recognizes that its own army is the master side, since (identification code of vehicle A) is (identification code of own army). Then, the collision avoidance operation for both the own army and vehicle A is determined, and the collision avoidance operation for vehicle A is instructed to vehicle A (step 5B4). In this case, as shown in FIG. 5, when car A and car B are facing each other, car B determines the action of avoiding each other to the right and passing each other as a collision avoidance action. If vehicle B is heading in the same direction, the overtaking operation is determined as a collision avoidance operation.

Thereafter, in step SB5, the self-determined collision avoidance operation is executed, and then the vehicle restarts (step 5B6).

Now, in step SA4, if car A receives a response from the other vehicle, it proceeds to step SA5, and if there is no response, it determines that there is no risk of collision with the other vehicle and proceeds to step SA6. In step SA5, B
Based on the information sent from the car, (identification code of car B)> (identification code of own army), the other party's B
Recognize that the car is the master side and your army is the slave side.

Then, in the next step SA5, after executing the collision avoidance operation instructed by car B, the car starts again (step SA5).
A6).

As a result of the above, as shown in FIG. 5, cars A and B pass each other by avoiding each other to the right, and then restart and return to the original travel route, completing the collision avoidance operation.

Here, for example, as shown within the frame of the two-dot chain line in FIG.
When the vehicle is traveling towards node N6 while moving away from the node N6, if the approach of either A or B is detected,
The vehicle determines in step SB2 that there is no risk of collision, proceeds to step SC6, and restarts the vehicle. Further, since there is no response in step SA4, vehicle A determines that there is no risk of collision, proceeds to step SA6, and starts driving again.

In this way, in the embodiment described above, when cars A and B approach each other and there is a risk of a collision, the one with the larger identification code always becomes the master side, and a collision between the master side and the slave side is avoided. It is designed to determine evasive action. Therefore, the central station 2 is not equally involved in this collision avoidance operation and can execute other processes.

In addition, in the embodiment described above, the other vehicle detectors 7A, 7
Although a configuration in which vehicles B are configured to emit identification radio waves to detect each other is used, it may be configured to detect other vehicles using ultrasonic waves having a different frequency from ultrasonic waves for distance measurement, for example. Further, although the polling/selecting method was used as the communication method between the central office 2 and cars A and B, it is of course possible to use a token passing method, for example.

[Effects of the Invention] As explained above, according to the present invention, each unmanned vehicle has
A communication means for mutually exchanging information and a detection means for detecting the approach of another unmanned vehicle are provided, and when each of the unmanned vehicles detects the approach of another unmanned vehicle by the detection means, While information regarding its own identification number, current location, and driving direction is transmitted to other unmanned vehicles via the communication means, each unmanned vehicle determines the risk of collision based on the transmitted information. The unmanned vehicle that determines whether or not the vehicle is at risk of collision will respond via the communication means with information regarding its own identification number, current location, and direction of travel, and from then on, the unmanned vehicle will determine whether there is a risk of collision. By exchanging information with other unmanned vehicles, they decide on actions to avoid collisions and execute them with each other, so collisions between unmanned vehicles can be prevented without relying on central processing at all. The effect is that it can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the electrical configuration of a self-supporting unmanned vehicle system according to an embodiment of the present invention, FIG. A timing chart for explaining the operation of the other vehicle detector provided in the unmanned vehicle in this embodiment, FIG. 4 is a flowchart for explaining the operation of the same embodiment, and FIG. 5 is a collision avoidance operation according to the same embodiment. FIG. 6 is a plan view for explaining the operation of a conventional self-supporting unmanned vehicle system. IA, IB...Unmanned vehicle (Car A, Car B), 2...
...Central station, 3...Communication equipment, 4...
...Command unit, 5...Travel unit, 6...Map memory, 7A, 7B...Other vehicle detector.

Claims (1)

[Claims] In an autonomous unmanned vehicle system consisting of a plurality of unmanned vehicles that recognize their current position and move to a work point where a work request occurs and perform the required work, relying on built-in map information. , Each of the unmanned vehicles is provided with a communication means for mutually exchanging information and a detection means for detecting that another unmanned vehicle is approaching, and each of the unmanned vehicles is configured to detect the other unmanned vehicle by the detection means. When detecting the approach of the unmanned vehicle, the unmanned vehicle transmits information regarding its own identification number, current position, and traveling direction to other unmanned vehicles via the communication means, while each unmanned vehicle, based on the transmitted information, The unmanned vehicle determines whether or not there is a risk of collision, and the unmanned vehicle that has determined that there is a risk of collision responds with its own identification number, current position, and information regarding the direction of travel via the communication means, and thereafter. A collision avoidance method in an autonomous unmanned vehicle system, characterized in that unmanned vehicles that are at risk of colliding with each other exchange information, determine actions to avoid a collision, and mutually execute the actions.