JP2900484B2 - Spin turn control method for unmanned vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of the Invention The present invention relates to a method for controlling a spin turn of an unmanned vehicle, and is intended to enable a quick and quick spin turn.

B. Summary of the Invention In the present invention, a high-speed running command is issued at the beginning of a spin turn, and thereafter, a command to run at a lower speed than at the beginning of a spin turn is issued.

C. Prior Art Unmanned guided vehicles (hereinafter abbreviated as "unmanned vehicles") are devices that transport parts, products, small items, etc. in various factories, warehouses, offices, and the like. As a system for guiding an unmanned vehicle along a traveling path unmannedly and traveling, an electromagnetic induction type, a magnetic type, a light induction type, and the like are generally adopted.

In the electromagnetic induction type, the position of the electric wire is determined by laying an electric wire along a traveling path, passing an alternating current through the electric wire, and detecting a magnetic field due to the electric wire current with a magnetic sensor (a pickup coil or the like) provided in the unmanned vehicle. Then, the steering is performed so that the deviation between the sensor position and the electric wire position is eliminated, that is, the magnetic sensor is positioned right above the electric wire.

In the light-guided system, a light reflecting tape is laid along the traveling path, and the reflected light emitted from the unmanned vehicle and reflected by the light reflecting tape is detected by an optical sensor provided on the unmanned vehicle, so that the light reflecting tape is provided. Is determined. Then, the steering is performed so that there is no deviation between the sensor position and the electric wire position, that is, the optical sensor is located directly above the light reflecting tape.

Here, the unmanned vehicle 1 will be specifically described with reference to FIG. In the unmanned vehicle 1, steering and rotational driving are performed by one front wheel 2, and two rear wheels 3 are driven wheels. Front wheel 2
Is driven by the traveling motor 4, and the moving distance is detected by the encoder 5. That is, a pulse is output from the encoder 5 according to the rotation amount of the front wheel 2, and the moving distance can be obtained by counting the number of pulses by a software counter provided in the control device 9. Steering of the front wheels 2 is performed by driving a steering motor 6, and a steering angle is detected by a potentiometer 7. The position of the guide line (electric wire or light reflecting tape) is detected by a course detection sensor (magnetic sensor or optical sensor) 8. Further, a mark plate detection sensor 10 is provided on the bottom surface of the unmanned vehicle 1, and a mark plate is attached to a required position on the traveling course.

The loading detection sensor 11 detects whether or not a load is loaded on the unmanned vehicle 1, and the detection signal is sent to the control device 9.

The control device 9 incorporates a traveling program,
It receives detection signals from the encoder 5, the potentiometer 7, the course detection sensor 8, the mark plate detection sensor 10, and the like, and controls the driving of the traveling motor 4 and the steering motor 6. Then, the number of mark plates detected by the mark plate detection sensor 10 is collated with the operation program, and an operation (for example, deceleration, stop, spin turn, restart, etc.) according to the detected number of mark plates is performed.

Here, the mode when the unmanned vehicle 1 makes a spin turn,
Explanation will be made based on FIG. 2 which is a bottom view. In order to make a spin turn when the unmanned vehicle 1 is at the position P1 shown by a solid line in the figure, first, the front wheels 2 are fixed at 90 °. From this state, the front wheel 2 is rotationally driven to turn the entire unmanned vehicle 1 (run in the direction of arrow A). Since the control device 9 is preset with data in which the front wheel rotation amount and the turning angle of the unmanned vehicle are preset, it is possible to determine how much (angle) the unmanned vehicle has turned by detecting the front wheel rotation amount. can do. When making a 90 ° turn, the front wheels 2 are stopped when the front wheels 2 are rotationally driven by a rotation amount corresponding to 90 °.
Then, the unmanned vehicle 1 stops at the position P2 indicated by the dotted line in the figure, and the 90-degree turn ends. Thereafter, the front wheels 2 are switched in a direction along the traveling direction of the unmanned vehicle 1. Similarly, when making a 180 ° turn, the front wheel 2 is stopped when the front wheel 2 is rotationally driven by a rotation amount corresponding to 180 °, thereby making a 180 ° spin turn.

D. Problems to be Solved by the Invention As described above, the front wheel 2 is stationary when the spin turn is performed, and then the front wheel 2 is rotationally driven. Therefore, when the rotational driving of the front wheel 2 is started after the stationary stationary is completed. The movement is like "Motatsui". If the rotation speed of the front wheel 2 during the spin turn is set to a high speed in order to eliminate the "scratch", the end position of the spin turn will be shifted widely. In other words, the inertia increases at high speeds. For example, just before the 90 ° turn (spin turn) is completed, even if the rotation of the front wheel 2 is stopped, the front wheel 2 slips or does not stop immediately. Therefore, the end position of the spin turn is shifted. Therefore, the rotation speed of the front wheel 2 during the spin turn has to be set low. As a result, at the start of the spin turn, "mottle" occurs, and the turning time required for the spin turn is further increased.

The present invention has been made in view of the above prior art, and provides a method of controlling a spin turn of an unmanned vehicle having a short turn time with no stiffness at the start of the spin turn.

E. Means for Solving the Problems According to the configuration of the present invention for solving the above problems, the turning angle of the unmanned vehicle is determined based on the rotation amount of the wheels during the spin turn, and the wheel rotation amount corresponding to the set turning angle is obtained. At the beginning of the spin turn, the wheel to be driven for the spin turn is rotated at a higher speed than the constant speed immediately before the stop of the spin turn in an unmanned vehicle that stops the rotation drive of the wheel and ends the spin turn Thereafter, the rotation speed is reduced stepwise until the spin turn stops, and the rotation is stopped. Further, when the load detection sensor detects that the load is loaded, it is detected that the load is loaded. The traveling command speed at the beginning of the start of the spin turn of the wheel to be rotationally driven for the spin turn is set to be faster than when there is no spin turn.

F. Action At the beginning of the spin turn, a high-speed running command is issued, so the spin turn is started promptly. After that, the vehicle runs at a steady speed running command lower than the initial, so it stops exactly at the set turn amount spin turn without slipping it can.

G. Examples The method of the present invention will be specifically described below. FIG. 1 shows an unmanned vehicle 1 to which the method of the present invention is applied. The control device 9 of the unmanned vehicle 1 stores a spin turn control program for controlling the operation during the spin turn. The control as shown in FIG. 3 is performed by the spin turn control program. That is, when the spin turn starts, 4
A command to rotate the front wheel 2 at a speed (4 km / h) is issued (). As a result, the spin turn starts agilely and does not cause "motatsuki". When the spin turn starts,
This time, it issues a command to rotate the front wheel 2 at the third speed (3 km / h). Therefore, the unmanned vehicle 1 turns at a steady speed during turning. At the end of the spin turn, a command to rotate the front wheel 2 at the first speed (0.5 km / h) is issued (). After turning 90 °, the front wheels 2 are stopped. Immediately before the stop, the front wheel 2 is rotating at the low speed, so that the end position of the spin turn is accurate without deviation. When a required time has elapsed since the start of the spin turn, it is determined that a spin turn error has occurred, the unmanned vehicle 1 is stopped, and a warning lamp (not shown) is turned on.

As described above, since the speed command during the spin turn is changed, the time required for a 90 ° spin turn is greatly reduced, and the accuracy of the spin turn termination is improved.

When the loading detection sensor 11 detects that a load is loaded, the traveling command speed at the start of the spin turn is a command that is 25% faster than the fourth speed (4 km / h). By doing so, a spin turn can be performed within the same time as when no load is applied, even when the load is applied.

When the spin turn ends, the process returns to the main running program ().

Note that the turning angle at which the fourth speed is changed to the third speed and the turning angle at which the third speed is changed to the first speed during the spin turn can be arbitrarily set on a program.

H. Effects of the Invention As described above in detail with the embodiments, according to the present invention, at the beginning of the spin turn, the wheels driven to rotate for the spin turn are driven at a higher speed than the constant speed immediately before the stop of the spin turn. The rotation is driven, and then the rotation is stopped by gradually reducing the constant speed until the spin turn is stopped, so that the spin turn can be started promptly and the time required for the spin turn can be shortened. In addition, when a load is detected by the load detection sensor, the start of the spin turn of the wheel to be rotated for the spin turn is shorter than when the load is not detected. Since the traveling command speed at the time is set faster, the spin turn can be performed within the same time as when there is no load even when the load is applied.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an unmanned vehicle to which the method of the present invention is applied, FIG. 2 is an explanatory view showing a spin-turn state, and FIG. 3 is a flowchart showing the operation of the present invention. In the drawings, 1 is an unmanned vehicle, 2 is a front wheel, 3 is a rear wheel, 5 is an encoder, 8 is a course detection sensor, and 9 is a control device.

Claims (1)

(57) [Claims] 1. A turning angle of an unmanned vehicle is determined based on a rotation amount of a wheel during a spin turn, and when reaching a wheel rotation amount corresponding to a set turning angle, rotation driving of the wheel is stopped to end the spin turn. In an unmanned vehicle, at the beginning of the spin turn, the wheels that are driven to rotate for the spin turn are driven to rotate at a higher speed than the fixed speed immediately before the stop of the spin turn, and then the rotation speed is gradually reduced until the spin turn stops. To stop rotation, and
When the load detection sensor detects that a load is loaded, the load of the wheel to be driven to rotate for the spin turn at the beginning of the spin turn is lower than when the load is not detected. A spin turn control method for an unmanned vehicle, wherein a traveling command speed is set to be high.