JPS6233614B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steering control method for an unmanned vehicle.

There is a programmed turning method using a trapezoidal function turning program as shown in FIG. 1, which allows an unmanned vehicle to turn from one cable to the other at a point where the guiding cables intersect. To make a turn using this method, first cancel the guided travel along one guide cable, then use the turning program to perform a programmed turn toward the other guide cable, and once the programmed turn is completed (the rudder angle returns to 0). (Tsutara) Immediately guide the train along the other guide cable. In this type of system, there is a large deviation in the stage at which the turn is completed due to disturbances such as a delay in steering operation due to road surface conditions or excessive turning due to vehicle slipping, and it is difficult to smoothly switch from a programmed turn to guided driving. difficult. That is, since the deviation is large at the time of switching to guided travel using the other guide cable, a problem may occur in which the vehicle is steered significantly due to sudden operation of the steering wheel.

This invention was made in view of the above points,
The present invention aims to provide a steering control system for an unmanned vehicle that can smoothly switch from programmed turning to guided driving.

In this invention, instead of switching to guided driving when the programmed turning ends as in the past, the system switches to guided driving regardless of the end of the programmed turning (even in the middle of the programmed turning, or for a while after the programmed turning ends). (even after the lapse of time), when the vehicle reaches the guidance cable, the vehicle switches to guided travel to achieve a smooth transition.

The present invention will be described in detail below with reference to an embodiment of the accompanying drawings. In the following explanation, the amount of change in the direction of the vehicle relative to the state before the start of the turn will be referred to as the turning angle, and the turning angle required to transfer onto the other guidance cable in parallel will be referred to as the predetermined turning angle. , A turning program in which a program turning program ends with the vehicle transferring parallel to the other guidance cable is called a turning program with a predetermined turning angle.
A turning program in which the programmed turning ends before transferring parallel to the other guiding cable is referred to as a turning program with less than the predetermined turning angle.

First, an example in which a turning program less than a predetermined turning angle is used will be described.

As shown in FIG. 2, consider the case where the unmanned vehicle 1 is transferred from the guide cable a to the guide cable b at a point where the guide cables a and b intersect at right angles (in this case, the predetermined turning angle is 90 degrees).

In FIG. 2, the guide cables a and b are laid along a course along which the unmanned vehicle 1 is guided to travel, and are supplied with an alternating current of a predetermined frequency.

Left and right wheels 4 of the front part 1a of the unmanned vehicle 1
Attitude angle and deviation detection coil 2 is located near a and 4b.
a and 2b are arranged. These attitude angle and deviation detection coils 2a and 2b are arranged in a "C" shape with respect to the center line of the vehicle body, and are connected in series so as to cancel the induced voltages with each other, as shown in Fig. 3. ing. These attitude angle and deviation amount detection coils 2a, 2b detect the attitude angle of the vehicle body (vehicle body centerline and guidance cable a or
It is used to detect the angle between the
In other words, when the vehicle body is riding parallel to the induction cable a or b (the attitude angle is zero), the same voltage is induced in the attitude angle and deviation detection coils 2a and 2b, so these They cancel each other out, and no voltage is output from the series circuit 2 of the coils 2a and 2b. When the vehicle body is at an angle with respect to the induction cable a or b, the coils 2a and 2b
Since voltages of different magnitude values are induced in
The series circuit 2 outputs the deviation voltage (voltage having a polarity and magnitude depending on the direction and magnitude of the attitude angle). Further, in this embodiment, by arranging them in a V-shape, it is possible to detect not only the attitude angle but also the lateral deviation of the vehicle body with respect to the guide cable a or b. In other words, when the vehicle body shifts laterally with respect to induction cable a or b, the induced voltage in the attitude angle detection coil closer to cable a or b increases, and conversely, the induced voltage in the attitude angle detection coil farther away from cable a or b increases. becomes small, so the difference between these voltages is extracted from the series circuit 2. In the end, the attitude angle and deviation amount detection coils 2a, 2
From the series circuit 2 of b, a voltage having a value corresponding to the attitude angle and lateral deviation of the vehicle body (the direction of the attitude angle and the direction of deviation correspond to the polarity, and the degree of the attitude angle and the degree of deviation correspond to the amplitude). is taken out.

Therefore, during guided travel, the vehicle 1 can be run along the guided cable a or b by controlling the steering so that the voltage from the series circuit 2 becomes zero.

The alternating current detection coil 3 is a coil arranged on the center line of the vehicle body so that its axis is perpendicular to the center line, and is used to detect the alternating current supplied to the induction cable a or b. ing.

Incidentally, in this embodiment, the vehicle 1 is made to turn from the guide cable a to the guide cable b using a trapezoidal function turning program as shown by the solid line in FIG. This turning program indicates the steering angle command according to the distance traveled from the starting point of the turn. Initially, the steering wheel is gradually turned while driving for distance X ₁ , and from distance X ₁ to distance X ₂ , the steering angle is changed. Keep the steering constant and drive while _gradually returning the steering from _distance
The idea is to return it to . When turning using the turning program shown in the solid line in Figure 4, vehicle 1 moves at a distance of X ₃ .
At the point where the angle of rotation with respect to the guiding cable a has reached 90°, it is approximately 70°. When turning using a conventional turning program with a predetermined turning angle (shown by the dotted line in Figure 4), the turning angle with respect to the guide cable a becomes 90 degrees when the rudder angle is completely returned to 0. However, as mentioned above, when using the turning program shown by the solid line in Figure ₄ , when the steering angle is returned to 0 (distance Do not transfer parallel to cable b. After _reaching distance
It is programmed to drive straight up to _X4 .

In this invention, when the vehicle 1 gets on the guidance cable b in the straight-ahead traveling section (distance X ₃ to X ₄ ), the guidance cable b
The vehicle is configured to switch to guided travel according to the following, so that a smooth transition can be made. Note that the specific operation for this switching will be described later.

A control system for realizing the turning method described above will be explained with reference to FIG. 5.

In FIG. 5, the detection signals of the attitude angle and deviation amount detection coils 2a and 2b are smoothed by a smoothing circuit 22 via a bandpass filter 6, and a steering command is issued to command the steering direction and steering amount of the steering wheel 17 during guided travel. It is guided to contact 10a of switch 10 as signal _S1 .

From the starting point of the turn, the distance detector 11 generates a pulse proportional to the traveling distance of the vehicle 1, and the counter 12
counts these pulses from the start of the turn and adds the counted value to the storage circuit 13 as a readout signal. The memory circuit 13 reads out a steering angle command value corresponding to this count value, and guides it to the contact 10b of the switch 10 as a steering command signal _S2 during turning.

The switch 10 selects one of the steering command signal S ₁ during guided travel led to the contact 10a and the steering command signal S ₂ during programmed turning led to the contact 10b. Addition point 14, amplifier 15,
The actuator 16 and the steering angle detector 18 execute steering control of the vehicle, and the steering angle detector 18 detects the actual steering angle of the steering wheel 17 and leads the detection signal to an addition point. Addition point 14 adds the deviation between the steering command value and the detected steering value to actuator 16 via amplifier 15, and drives steering wheel 17 so that the deviation becomes zero.

Next, the switching operation of the switch 10 will be explained.

The switching of the switch 10 is performed by a command from the selection control circuit 21. During guided travel, the selection control circuit 21 connects the switch 10 to the contact 10a, supplies the steering command signal _S1 from the attitude angle and deviation detection coils 2a and 2b to the addition point 14, and causes the vehicle 1 to travel in the guided travel. Further, when a turning command is applied, the switch 10 is connected to the contact point 10b. At this time, the counter 12 starts counting operation, and the memory circuit 13
From there, a steering command signal _S2 is read out based on the turning program shown by the solid line in FIG. 4 and is supplied to the addition point 14. Vehicle 1 receives this steering command signal S ₂
Perform program rotation based on the following. Once the programmed turning is executed and the following conditions are satisfied, the vehicle will switch back to guided travel. One of the conditions is that the signals from the attitude angle and deviation detection coils 2a and 2b
The value of S ₁ is within a predetermined low value ±Vs. In _{other words} , while the steering angle is maintained at ₀ while moving from distance Varies depending on distance. Specifically, at first, the coil 2b approaches the induction cable b, and the induced voltage in the coil 2b becomes larger than the induced voltage in the coil 2a, so the signal S ₁
now has a polarity corresponding to coil 2b,
As the vehicle moves forward from there, the induced voltage in the coil 2a increases, so the signal _S1 approaches zero. As the process progresses further, the induced voltage in the coil 2a becomes larger than the induced voltage in the coil 2b, and the signal _S1 has a polarity corresponding to that of the coil 2a. Therefore, if the value of signal S ₁ is around 0, vehicle 1
It can be determined that the line is almost on top of the cable b. Therefore, in this embodiment,
A window comparator 20 is provided, to which a signal S ₁ is applied.
If the signal _S1 falls within the range of a predetermined low value ±Vs set by the window comparator, it is determined that the vehicle 1 is almost on the cable b, and the signal S1 is output from the window comparator 20. 1 for switching the signal from switch 10 to contact 10a
This is added to the selection control circuit 21 as one condition. By the way, window comparator 20
The switch 26 provided on the input side of the vehicle 1
This is to operate the window comparator 20 only when the driver is traveling straight to cross the induction cable b, and the window comparator 27
It is turned on and off by the signal from. That is,
The comparator 27 inputs the count value of the counter 12, turns on the switch 26, and supplies the signal _S1 to the window comparator 20 when the count value is greater than or equal to the distance _X3 . Further, another condition for switching the switch circuit 10 to the contact 10a is a signal from the alternating current detection coil 3. This signal is small when the vehicle 1 is far from the induction cable b, and becomes large when the vehicle 1 is close to the induction cable b, so if the value is smaller than the set value, it is assumed that the vehicle 1 is disconnected from the induction cable a or b, and the signal is sent to the contact 10a. Avoid switching. That is, the signal from the alternating current coil 3 is passed through the bandpass filter 7 and the rectifier 2.
3 and the comparator 25 via the smoothing circuit 24.
In addition, if the value of the applied signal is less than a preset value, the comparator 25 assumes that the vehicle 1 is disconnected from the cable b, applies a course out signal to the selection control circuit 21, and switches the switch 10.
It is designed to prevent the switching of

As described above, the selection control circuit 21 determines whether vehicle 1 is
X ₃ or more, the signal S ₁ from the attitude angle and deviation amount detection coils 2a and 2b is within the range of ±Vs, and the course out signal is not issued, and the vehicle 1 is almost on the induction cable b. It is determined that the switch 10a has been transferred to the switch 10a.
to perform guided travel using the guiding cable b.

As explained above, according to the present invention, when the vehicle is programmed to make a turn from one guide cable to the other at a point where the guide cables intersect, the vehicle remains unchanged after the turn by the turning program is completed. Since the vehicle is driven straight and switches to guided travel when it almost reaches the other guiding cable, it is possible to smoothly switch from programmed turning to guided travel.

[Brief explanation of the drawing]

Fig. 1 is a graph showing a trapezoidal function commonly used in programmed turning; Fig. 2 is a schematic plan view showing the state of an unmanned vehicle turning according to the present invention;
FIG. 3 is a schematic plan view showing the arrangement and connection state of the attitude angle detection coil, FIG. 4 is a graph showing an example of a trapezoidal function used in the present invention, and FIG. 5 is a diagram showing an embodiment of the present invention. It is a block diagram. 1... Unmanned vehicle, 2a, 2b... Attitude angle detection coil, 3... Alternating current detection coil, 4... Vehicle.

Claims (1)

[Claims] 1. When an unmanned vehicle is turned from one guidance cable to the other at a point where two guidance cables intersect, the distance traveled during the turn and the first steering angle command value are calculated. The function is to start a turn from the turning start point, turn the vehicle by a turning angle that is less than the predetermined turning angle required for transfer before the vehicle intersects the other guiding cable, and then drive the vehicle straight. storage means for storing a turning program to cause the vehicle to turn; means for detecting the travel distance of the vehicle from the turning start point; means for reading out the first steering angle command value from the storage means in accordance with the detected value; means for detecting a second steering angle command value according to the attitude angle of the vehicle body and the amount of course deviation from the guidance cable based on the magnetic field of the cable; and the first steering angle command value or the second steering angle command value. a selection means for selecting one of the above, a steering control means for executing steering control of the vehicle based on the selected signal, and a steering control means for controlling the steering of the vehicle based on the selected signal; Let them choose;
After that, when the first rudder angle command value becomes 0 and the second rudder angle command value falls within a predetermined setting range, the selection control means selects the second rudder angle command value. Steering control method for driving vehicles.