JP2829933B2 - Control device for autonomous vehicle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for an autonomous vehicle, and more particularly to a control device for an autonomous vehicle that slowly reduces a control torque from a steering actuator.

2. Description of the Related Art Conventionally, when an autonomous traveling vehicle is performing autonomous traveling and an automatic steering device is operating to perform a turning traveling, the automatic steering torque suddenly becomes zero when the driver cancels the automatic steering function. Therefore, the steering suddenly returns to the neutral position.

Also, in order to prevent the steering from suddenly returning to the neutral position, the automatic control system gradually reduces the automatic steering torque to smooth the transition to manual operation, or the driver holds the steering appropriately. Only when the automatic control system confirms that the operation has been performed, the control is shifted to the manual operation.

(Problems to be Solved by the Invention) In an autonomous traveling vehicle, the intention of the human being who is the driver is given priority, and when the driver attempts to cancel the autonomous traveling, even if an abnormality occurs in the control system. The transition to the manual operation state must be ensured.

In the above conventional example, when the automatic steering function is released, the automatic steering torque suddenly becomes zero, so that the steering suddenly returns to the neutral position, and the running state of the vehicle may become unstable.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above problems, and has the following configuration as one means for solving the above problems.

That is, an outside world recognition unit for recognizing the outside world, a traveling control unit for controlling traveling of the vehicle based on a result recognized by the outside world recognition unit, an autonomous traveling by the traveling control unit and a manual operation by a driver operation A traveling switching means for switching between operation and operation; and a means for slowly reducing the control torque from the automatic steering actuator when the traveling switching means switches from autonomous traveling to manual traveling.

(Operation) In the above configuration, the control device of the autonomous traveling vehicle works so as to slowly decrease the control torque from the automatic steering actuator when the vehicle is switched from the autonomous traveling to the manual traveling.

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

First Embodiment FIG. 1 shows a structure of a damper mechanism of a control device according to a first embodiment of the present invention. The steering actuator for automatic steering provided in the control device of the present embodiment is well known and will not be described.

In FIG. 1, a damper cylinder 1 is a two-chamber hydraulic cylinder mounted on a tie rod 2 or a part performing a reciprocating motion equivalent to the tie rod 2. The piston partition wall 3 has a small-diameter relief port valve 3a. ing.
Normally, since the two cylinder chambers of the damper cylinder 1 are connected by an external shutter valve 4, they do not function as a damper. Therefore, when the manual movement or the automatic operation is continued, the shutter valve 4 does not function as a damper mechanism.

Next, a description will be given of a damper operation when the driver switches to the manual driving when the vehicle is traveling autonomously on a curve and the steering is displaced to the left or right.

 FIG. 2 is a timing chart of the damper operation.

Normally, the automatic driving system stops its operation when switching from automatic operation to manual operation unless it has a special function,
The automatic control torque that rotates or holds the steering suddenly becomes zero. Therefore, the steering returns to the neutral position due to mechanical alignment, and the vehicle attempts to go straight.

In FIG. 2, when the operation is switched from the automatic operation to the manual operation at the point of time, the shutter valve 4 is closed to enable the damper function. As a result, the neutral return operation of the steering becomes slow, and the damper function is released (FIG. 2) when a predetermined time elapses or a condition described later is satisfied.

The time during which the damper is effective, that is, the time constant of the damper, is desirably 3 to 4 seconds or more so that the steering can return to the neutral position stably. However, when the driver releases autonomous driving and intentionally switches to manual operation and immediately shifts to steering operation, the steering operation becomes heavy while the damper function is effective. Therefore, the above-mentioned problem is solved by the damper operation circuit shown in FIG.

That is, in FIG. 3, during the automatic operation, the output of the gate 12 is logic low, so that the damper function is disabled. However, when the automatic operation is canceled and a logical high is input to the input 12a of the gate 12, the output of the gate 12 becomes a logical high, so that the damper function is enabled. At this time, when the steering returns to the neutral position or when the steering torque due to the driver's operation of the steering is detected, the gate is turned off.
A logic high is applied to at least one input of 11. As a result, the SR flip-flop 10 is reset, and the input 12b of the gate 12 becomes logic low, so that the damper function is invalidated.

Regarding the release procedure of the damper function described above,
This will be described with reference to the flowchart shown in the figure.

At step S1 in FIG. 4, it is determined whether or not the automatic operation has been canceled. If the cancellation can be detected, the shutter valve 4 is closed at step S2. At this point, the damper function is enabled. Then, the steering torque by the driver is detected in step S3, and if the torque can be detected, the process proceeds to step S5.
Cancel the damper function immediately.

However, if the torque cannot be detected in step S3, it is determined in step S4 whether the steering has returned to the neutral position. Therefore, if return to the neutral position can be detected,
Proceeding to step S5, the damper function is released. If the return to the neutral position cannot be detected, the process returns to step S3, and the steering torque is detected again.

As described above, according to the present embodiment, when switching from automatic driving to manual driving, the damper function operates so that the neutral return operation of the steering is slowed down. There is an effect that steering instability caused by a proper steering return can be avoided.

By the time the steering torque can be detected by the steering operation before the steering returns to the neutral position, the damper function is released, facilitating introduction to manual driving.
There is an effect that the damper function does not hinder the manual operation.

Second Embodiment Next, a second embodiment will be described.

FIG. 5 is a block diagram for explaining steering control in the control device of the present embodiment.

In the figure, a target value for controlling the steering is input to the steering controller 20, and the automatic steering torque is gradually reduced by adding a process described later to the output signal.

In the steering control circuit shown in FIG. 5, the feedback loop has a first-order lag element with a storage function,
At the time of switching from automatic operation to manual operation, the attenuation signal of the controller output signal immediately before switching is used.

In FIG. 5, during normal automatic steering, switch 1 (SW1) 2
5 is tilted to the side, and the switch 2 (SW2) 26 is tilted to the side, so that the output of the primary delay element 21 is open. Therefore, the steering control circuit of FIG.
This is the same as the feedback control circuit of the conventional motor.
However, cancel the automatic operation and switch SW1 and SW2 to
Defeat the side, so that the output waveform of the steering controller 20 is shown in Figure No. 6 (a), it becomes zero at time t _1.

On the other hand, the output waveform of the first order lag element 21 as FIG. 6 (b), gradually decays to zero from time t _1. By applying this damping signal to the motor 22, the automatic steering torque is gradually reduced.

FIG. 7 shows a circuit when the first-order lag element is realized by an electric element.

As described above, according to the present embodiment, by providing the feedback loop of the steering control circuit with a first-order lag element having a storage function, a signal phase shift occurring at the time of switching from automatic driving to automatic driving can be prevented. Thus, there is an effect that the automatic steering torque can be gradually reduced.

(Effects of the Invention) As described above, according to the present invention, when switching from autonomous traveling to manual traveling with the steering turned off,
There is an effect that the neutral return operation of the steering becomes slow, and it is possible to prevent the running from becoming unstable due to the sudden return of the steering.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a damper mechanism of a control device according to a first embodiment of the present invention, FIG. 2 is a timing chart of a damper operation of the control device of the first embodiment, and FIG. FIG. 4 is a flow chart showing a procedure for releasing a damper function, FIG. 5 is a block diagram for explaining steering control in a control device of a second embodiment, and FIG. 6 is a signal of a steering control circuit. FIG. 7 is a diagram showing a waveform, and FIG. 7 is a diagram showing a circuit when a first-order lag element is realized by an electric element. In the figure, 1 ... damper cylinder, 2 ... tie rod, 3a
…… Relief port, 4… Shutter valve, 20 …… Steering controller, 21 …… First-order lag element, 22 ……
It is a motor.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-291099 (JP, A) JP-A-2-303936 (JP, A) JP-A-2-73905 (JP, U) (58) Survey Field (Int.Cl. ⁶ , DB name) G05D 1/02

Claims (1)

(57) [Claims] 1. An outside world recognizing means for recognizing an outside world, a traveling control means for controlling traveling of a vehicle based on a result recognized by the outside world recognizing means, an autonomous traveling by the traveling control means and a driver A travel switching means for switching between manual travel by operation and a means for slowly reducing the control torque from the automatic steering actuator when the travel switching means switches from autonomous travel to manual travel. Control device for autonomous vehicles.