JPH081563B2 - Autonomous vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an autonomous vehicle that allows a bus, a passenger car, or the like to travel unmanned along a preset course.

B. Conventional technology Conventionally, the unmanned driving of buses and passenger cars No. 6
The autonomous vehicle shown in the figure is known. This autonomous vehicle travels on a predetermined course while measuring the position of the own vehicle with an ultrasonic rangefinder, and is equipped with the own vehicle position measuring device shown in FIG. That is, the own vehicle position measuring device is the ultrasonic sensor 1 mounted on the left and right side surfaces of the front part of the vehicle.
A steering angle sensor 2 for detecting the steering angle of the front wheels, a control circuit 3 for calculating the ultrasonic wave emitting direction (distance detection direction) of the ultrasonic sensor 1 and the steering angle, and an ultrasonic signal by the output signal of the control circuit 3. An actuator 4 for changing the distance detection direction of the sensor 1 and an actuator 9 for changing the steering angle according to the output signal of the control circuit 3 are also included.

In such an autonomous vehicle, the distance l between the vehicle side surface and the guardrail 5 is determined by the time it takes for the ultrasonic waves emitted from the ultrasonic sensor 1 to be reflected and returned to the guardrail 5 installed along the roadside. It is detected and the vehicle travels while controlling the steering angle θ so that the distance 1 is kept substantially constant. Since the direction of the vehicle with respect to the guardrail 5 inclines when traveling on a curve, if the distance detection direction of the ultrasonic sensor 1 is fixed vertically to the side surface of the vehicle, the ultrasonic signal reflected by the guardrail 5 cannot be received. When running, as shown by arrows A and B in FIG. 7, the ultrasonic sensor 1
Is rotated in the same direction as the steering direction and the distance detection direction is changed to the angle φ calculated by the equation (1). Here, the angle φ is obtained by the control circuit 3 from the following equation as an average value of the steering angle θ over the past m times.

The direction of the ultrasonic sensor 1, that is, the distance detection direction, can be adjusted by the actuator 4 as shown in the partially enlarged view of FIG. 8, and the angle φ calculated by the equation (1) of the autonomous vehicle is φ = When 0, it is the vertical direction of the side surface of the autonomous vehicle, when φ> 0, it is a direction rotated counterclockwise from the direction of φ = 0, and when φ <0, it is clockwise from φ = 0. It is the direction of rotation. Therefore, from the equation (1), the ultrasonic sensor 1 is rotated in the same direction as the steering direction according to the steering angle θ, and the distance detection direction becomes the angle φ. As a result, the reflected wave from the guardrail 5 is transmitted to the ultrasonic sensor 1
When the vehicle travels on a curve, it can perform autonomous traveling almost the same as when traveling straight, by measuring the distance 1 by receiving the certainty.

The speed at which the vehicle travels, the position at which the vehicle is stopped, etc. are controlled by another control device (not shown).

C. Problems to be Solved by the Invention By the way, in such an autonomous vehicle, when an obstacle such as a person or an object appears on the road surface in front of the vehicle, it is necessary to avoid the obstacle, and the obstacle in front of the vehicle must be avoided. Obstacle avoidance steering is performed by detecting an object with, for example, a laser radar. For example, an autonomous vehicle with the positional relationship shown in FIG.
When an obstacle 11 appears in front of 10, the laser radar detects it and changes the steering angle θ in the clockwise direction to avoid the obstacle.

However, in the above-mentioned conventional autonomous vehicle, since it is not determined whether the vehicle is traveling in a curve or an obstacle avoidance operation, the ultrasonic sensor 1 is in the same steering direction as shown by arrows A and B in FIG. 9 during the avoidance operation. The steering angle θ changes by an angle corresponding to the change in the steering angle θ. Therefore, the ultrasonic waves emitted from the ultrasonic sensor 1 during the obstacle avoidance operation are reflected by the guardrail 5 in directions A ′ and B ′ completely different from the vehicle, and the guardrail 5
It becomes impossible to measure the distance to and it becomes impossible to drive autonomously.

A technical object of the present invention is to determine whether the steering of the vehicle is a curve traveling or an obstacle avoidance operation, and always accurately measure the distance to the guide extended to the side of the vehicle.

D. Means for Solving the Problem The present invention will be described with reference to FIG. 1, which is a diagram corresponding to claims. An autonomous vehicle according to the present invention is provided on a side surface of a vehicle.
A distance detecting means 1 for detecting a distance to a guide 5 on the side of the vehicle extending along a traveling path, an obstacle detecting means 6 for detecting an obstacle in front of the vehicle, and a steering means 9 for steering the vehicle. And the steering angle detecting means 7 for detecting the steering angle of the vehicle steered by the steering means 9 and the distance to the guide 5 on the side of the vehicle detected by the distance detecting means 1 are autonomous so as to be kept substantially constant. While controlling the steering means 9 for traveling,
When an obstacle is detected by the obstacle detection means, the steering control means 8B for controlling the steering means 9 so as to avoid the obstacle and the steering by controlling the steering means 9 by the steering control means 8B are for the autonomous traveling. Determination means 8A for determining whether the steering is for avoiding an obstacle, and if it is determined that the steering is for avoiding an obstacle, the steering angle is detected in the opposite direction based on the steering angle detected by the steering angle detecting means 7. Distance detection means 1 according to the steering angle
The direction of the distance detection by the distance detecting means 1 is changed in the same direction as the steering direction based on the steering angle detected by the steering angle detecting means 7 when the steering direction of the autonomous traveling is determined. By providing the direction changing means 4, the above technical problem is solved.

E. When the action determination means 8A determines that the steering is for avoiding an obstacle,
The distance detection means 1 is rotated in a direction opposite to the steering direction of the obstacle avoidance steering according to the steering amount, and the distance detection direction is changed. When the determination unit 8 determines that the steering is for curve traveling in autonomous traveling, the distance detection unit 1 is rotated in the same direction as the steering direction according to the steering amount to change the distance detection direction. As a result, it is possible to accurately measure the distance to the inductor 5 on the side of the vehicle both when avoiding an obstacle on the road surface and when traveling on a curve.

In the above D and E for explaining the configuration of the present invention, the reference numerals of the embodiments are used to make the present invention easy to understand, but the present invention is not limited to the embodiments.

F. Embodiment FIG. 2 is a block diagram showing an embodiment of the present invention.
The same parts as those of the conventional configuration are indicated by the same symbols, and the differences will be mainly described below.

In the figure, reference numeral 6 denotes a laser radar that emits laser light in front of the vehicle, and detects the presence or absence of an obstacle ahead and the distance to the obstacle from the time until the reflected wave of the laser light is received. Reference numeral 7 is a rotary encoder for detecting vehicle speed attached to the axles of the left and right rear wheels, and 8 is a control circuit for controlling the actuators 4 and 9, which detect signals from the ultrasonic sensor 1, the laser radar 6, and the rotary encoder 7. In response, the steering actuator 9 and the sensor actuator 4 are controlled by executing various calculations to be described later.

 Hereinafter, the operation will be described.

First, the ultrasonic sensor 1 emits an ultrasonic wave toward the card rail 5 installed on the traveling road side and receives a reflected wave thereof, as in the conventional case. The distance 1 between the vehicle and the guardrail 5 is detected from the time interval between the launch and the reception, and the steering angle θ is controlled by the steering actuator 9 so that the distance 1 to the guardrail 5 is kept substantially constant. Drive the vehicle.

FIG. 2 is an example of a processing procedure for changing the distance detection direction of the ultrasonic sensor 1, which is executed by the control circuit 8. First, after reading the current steering angle θ detected by the steering angle sensor 2,
It is checked whether the laser radar 6 detects any obstacle in front of the vehicle (steps S1 and S2). When the obstacle is not detected in front of the vehicle, the rotation angle φ is obtained by the above-mentioned equation (1), and a signal for setting the rotation angle φ as the distance detection direction of the ultrasonic sensor 1 is input to the actuator 4 (step S8). As a result, the ultrasonic sensor 1 rotates in the same direction as the steering direction, and the rotation angle is φ.

If an obstacle is detected by the laser radar 6,
The distance from the laser radar 6 to the obstacle is measured by the time from the emission of the laser light to the reception of the reflected light, and the traveling speed of the vehicle is measured by the pulse period output from the rotary encoder 7 (step S2, S
3).

Here, the distance to the obstacle measured at the previous detection timing is l ₀ , and the distance measured at the current detection timing is
l ₁ , the traveling speed measured at the current detection timing is v, and the detection cycle is δt. If the obstacle captured by the laser radar 6 is a true obstacle such as a person or an object appearing on the traveling road surface, the distance to the obstacle is shortened in linear proportion to the traveling speed v, and therefore (l ₀ − The relationship of l ₁ ) / δt = v (2) holds. However, when the laser radar 6 detects the guardrail 5 during the curve traveling as an obstacle, the relationship between the traveling speed v and the distance (l ₀ −l ₁ ) becomes a non-linear relationship, and the above equation (2) is Not satisfied.

Therefore, the control circuit 8 determines whether or not the above expression (2) is satisfied (step S5), and when it is not satisfied, it is determined that the guardrail 5 during the curve traveling is detected as an obstacle. That is, it is determined that the steering is for autonomous traveling, and the rotation angle of the ultrasonic sensor 1 is changed to the angle φ represented by the average value of the steering angles θ of the past m times and the distance detection direction is changed (step S8). When the expression (2) is established, it is determined that a true obstacle is detected on the traveling road surface. That is, it is determined that the steering is for avoiding an obstacle. And
The steering angle actuator is driven as described below so that the avoidance operation is performed when the distance l ₁ measured this time reaches the threshold value or less, and the ultrasonic sensor 1 is calculated by the following formula (3).
The angle φ n ₊₁ indicating the distance detection direction of is obtained, and this angle φ n ₊₁
Is input to the sensor actuator 4 to change the distance detection direction of the ultrasonic sensor 1 to the direction opposite to the steering direction (steps S5 to S7).

φn ₊₁ = φn− (v− / L) · θ · δt (3) However, φn ₊₁ : angle indicating the distance detection direction of the ultrasonic sensor 1 obtained this time φn: of the ultrasonic sensor 1 obtained last time Angle indicating the distance detection direction v: Traveling speed L: Wheel base θ: Steering angle θ δt: Detection cycle As a result, during operation to avoid a true obstacle on the road surface, it is indicated by arrows A and B in Fig. 4. So that the ultrasonic sensor 1
Is rotated in the opposite direction to the steering direction and the rotation angle is φn ₊₁
It is said. As a result, the distance to the guardrail 5 can be accurately measured even during the avoidance operation.

In the configuration of the above embodiment, the ultrasonic sensor 1 serves as the distance detecting means, the radar laser 6 serves as the obstacle detecting means, the steering angle detecting means for the steering angle sensor 2 and the control circuit 8 serve as the steering control means. The actuator 9 constitutes the steering means, the control circuit 8 constitutes the determination means, the control circuit 8 and the sensor actuator 4 constitute the direction changing means, and the guardrail 5 is the dielectric.

 Here, a specific example of the obstacle avoidance operation will be described.

In the normal traveling state, the vehicle travels in accordance with a traveling command PR that indicates the traveling speed, the distance to the guardrail, the steering angle during traveling, and the length of the road. When an obstacle is detected, the following avoidance operation is performed.

FIG. 5 shows a vehicle VE and an obstacle OB, where the vehicle is the third one described above.
When the obstacle OB is detected in step S5 of the figure, the distance between the guardrail and the vehicle VE is detected based on the output signal from the ultrasonic sensor 1, and if the vehicle VE is traveling on the left side of the road center, it is on the right side. If the vehicle is traveling on the right side of the road center, a new traveling target point OP is set on the left side. And the vehicle
The steering angle is controlled so that VE moves toward the traveling target point OP. If the obstacle is still detected even after the avoidance action, the vehicle
Stop VE. When the obstacle avoidance is completed, the driving command PR is issued again.
The vehicle travels based on. In addition, during obstacle avoidance operation,
The signal from the ultrasonic sensor on the opposite side of the obstacle is used for the distance from the guardrail to the vehicle VE.

If an obstacle is detected by a TV camera instead of by a laser radar, more accurate avoidance operation becomes possible.

In this case, two TV cameras are installed on the top and bottom to detect obstacles in stereo, and the left edge coordinates of the obstacles are detected as shown in FIG.
LC, right edge coordinate RC, and tip coordinate TC are calculated. From this angular coordinate, the distance WL to the left end coordinate and the guardrail, and the distance WR to the right end coordinate and the guardrail are obtained. Then, it is determined whether any larger value is larger than the vehicle width of the vehicle VE,
If the vehicle width is large, you cannot pass through, so stop the vehicle VE. If the vehicle width is smaller, the target point PO is set at the axis center of the larger WL and WR, and the steering angle is controlled so that the vehicle VE moves toward the target point PO. When the obstacle avoidance is completed, the traveling of the vehicle is controlled by the traveling command PR again.

In the above embodiment, the guardrail 5 on the side of the vehicle and the obstacle ahead may be detected using a microwave radar. Alternatively, the present invention can be applied to a device that images the side of the vehicle with a TV camera or the like and processes the image to detect the distance to the guardrail. In this case, the optical axis of the image pickup means such as the TV camera is set to the guardrail It will be rotated so as to face each other at a right angle. Further, the judgment as to whether to avoid the obstacle avoidance steering or to steer the curve traveling in the autonomous traveling is made based on the speed of the own vehicle and the distance to the obstacle, but not limited to this, it is performed based on the image of the TV camera described above. It is also possible.

Further, the present invention can be applied to not only buses and passenger cars but also autonomous vehicles that carry unmanned luggage in factories or the like.

G. Effect of the Invention As described above, according to the present invention, during obstacle avoidance steering, the direction of distance detection by the distance detection means for detecting the distance to the guide is changed by rotating in the opposite direction to the steering direction. ,
The distance detection direction is changed by rotating in the same direction as the steering direction when driving autonomously on a curve. It is possible to drive autonomously while accurately measuring.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to claims. FIG. 2 is a block diagram showing an embodiment of the present invention, FIG. 3 is a flow chart showing an outline of a control operation for changing the direction of distance detection by an ultrasonic sensor, and FIG. 4 is a flowchart showing obstacle avoidance steering in the embodiment. 5 is a diagram showing an example of distance detection by an ultrasonic sensor, FIGS. 5 (a) and 5 (b) are diagrams for explaining a target point PO, and FIG. 6 is a block diagram showing a configuration of a conventional autonomous vehicle, FIG. Is a diagram showing an example of distance detection by an ultrasonic sensor when a conventional autonomous vehicle is traveling in a curve, FIG. 8 is a diagram showing an angle φ in the distance detection direction of the ultrasonic sensor, and FIG. 9 is a conventional vehicle position. It is a figure showing an example of distance detection of an ultrasonic sensor during obstacle avoidance steering in a measuring device. 1: Ultrasonic sensor, 2: Steering angle sensor 3, 8: Control circuit 4: Sensor actuator 5: Guardrail, 6: Laser radar 7: Rotary encoder 9: Steering actuator 10: Autonomous vehicle, 11: Obstacle

Claims (1)

[Claims] 1. A distance detecting means which is provided on a side surface of a vehicle and which detects a distance to a side vehicle extending along a traveling path, and an obstacle detecting means which detects an obstacle in front of the vehicle. The steering means for steering the vehicle, the steering angle detecting means for detecting the steering angle of the vehicle steered by the steering means, and the distance to the vehicle side guide detected by the distance detecting means are kept substantially constant. Steering control means for controlling the steering means for autonomous traveling as well as controlling the steering means so as to avoid an obstacle detected by the obstacle detection means, and the steering control means for steering the steering wheel. Determining means for determining whether the steering by controlling the means is the steering for the autonomous traveling or the steering for avoiding the obstacle, and the steering detected by the detecting means if the steering for avoiding the obstacle is determined. Based on the corner The direction of distance detection by the distance detecting means is changed in a direction opposite to the steering direction in accordance with the steering angle, and if it is determined that the steering is autonomous traveling, the steering direction is changed based on the steering angle detected by the detecting means. An autonomous traveling vehicle comprising: direction changing means for changing the direction of distance detection by the distance detecting means in the same direction.