JP3006115B2 - Vehicle attitude control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle attitude control device for maintaining a running attitude of a vehicle relative to a road surface.

[0002]

2. Description of the Related Art Conventionally, automation of vehicle acceleration / deceleration control has been advanced. In this case, an inter-vehicle distance detection sensor for detecting an inter-vehicle distance between a host vehicle and a preceding vehicle is essential. Such an inter-vehicle distance detection sensor is, for example, a laser radar, and detects the inter-vehicle distance by measuring a time required for a laser beam emitted from the own vehicle to be reflected by a preceding vehicle and returned.

[0003] Such a laser radar has an improved detection accuracy and has a predetermined range, for example, 12 dB.
In order to enable detection up to about 0 m, the laser beam has a considerably high directivity.

[0004] Therefore, when the attitude of the vehicle on which the laser radar is mounted changes and the irradiation direction of the laser beam changes, the laser beam deviates from the vehicle in front and the laser radar cannot catch the vehicle in front. There was a problem that it was easy.

[0005] In addition, when the attitude of the vehicle changes due to an increase or decrease in the number of occupants or the like, the attitude of the laser radar accompanying the change in the attitude of the vehicle at that time is controlled by operating a command switch. It shows that a posture detector using a weight or the like is used for detection, and the posture of the laser radar is automatically adjusted in accordance with the detection result to correct the irradiation direction of the laser beam in a predetermined direction.

[0006]

[Problems to be solved by the invention]
In the device described in JP-A-153400, an attitude detector that detects an attitude in a static state is used. This is because, in this conventional example, the change in the number of passengers is intended to be a change in the attitude caused by a thing that does not change for a while after being once boarded. When it changes, it is done manually.

Therefore, this apparatus cannot cope with a dynamic posture change due to acceleration or deceleration during running, such as a fall of the vehicle at the time of acceleration or a front turn at the time of deceleration. However, there is a problem that a laser beam is deviated from a vehicle in front of the vehicle while the vehicle is running, and a laser radar cannot capture the vehicle in front of the vehicle.

SUMMARY OF THE INVENTION The present invention has been made to solve this problem. By controlling the vehicle attitude while the vehicle is running to be constant with respect to the road surface, it is possible to prevent a laser radar from being erroneously captured. It is an object to provide a vehicle attitude control device.

[0009]

A vehicle attitude control device according to the present invention comprises an inter-vehicle distance sensor for detecting an inter-vehicle distance between a preceding vehicle and a host vehicle, a speed sensor for detecting a speed of the host vehicle, A vehicle attitude adjusting means for controlling the vehicle attitude by adjusting the relative position or movement of the vehicle body and the wheels, and accelerating and decelerating the own vehicle based on the inter-vehicle distance detected by the inter-vehicle distance sensor and the speed detected by the speed sensor. Predicts and anti-squats when the vehicle is predicted to accelerate
Control when the host vehicle is predicted to decelerate.
And control means for controlling the vehicle attitude adjusting means so as to perform a chidive control .

[0010]

In the vehicle attitude control device having the above-mentioned structure, when the inter-vehicle distance sensor determines that the inter-vehicle distance increases or decreases, the control means predicts that the vehicle will accelerate or decelerate to change its attitude. Before the acceleration or deceleration, vehicle attitude control such as anti-squat control or anti-dive control is performed by controlling the vehicle attitude adjusting means, so that the attitude of the vehicle during traveling is kept constant with respect to the road surface.

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a vehicle attitude control device according to the present invention.

As shown in the figure, the vehicle attitude control apparatus includes a laser radar 3 for detecting an inter-vehicle distance in a vehicle 2 and front and rear wheels for controlling a spring constant, a damping force and a stroke as vehicle attitude adjusting means. Four active suspensions 4, 5; two stroke sensors 6, 7 for detecting the stroke (vehicle height) of each active suspension 4, 5; an acceleration sensor 8 for detecting the acceleration and deceleration of the vehicle 2; The control system includes a speed sensor 9 for detecting the speed of the vehicle 2 and a control computer 10. The control computer 10 controls each of the active suspensions 4 and 5 based on detection signals from the laser radar 3, each of the stroke sensors 6 and 7, the acceleration sensor 8 and the speed sensor 9, to thereby be described later. The attitude of the vehicle 2 is controlled as described above. Further, the laser radar 3 is mounted on the vehicle 2.
The direction of the laser beam 3 a emitted forward of the vehicle is constant with respect to the vehicle 2.

As an active suspension, for example, there is an active suspension in which air filled in an air chamber of a pneumatic cylinder (air spring) has a spring function to control a spring constant, a damping force, and a vehicle height.

Next, the attitude control by the vehicle attitude control apparatus 1 having the above configuration will be described with reference to the flowchart of FIG.
This will be described with reference to the explanatory diagrams of (B) and (C).

First, the control computer 10 reads the inter-vehicle distance L between the vehicle 2 and the preceding vehicle 11 from the laser radar 3 (S-1), and thereby determines the presence or absence of the preceding vehicle 11 (S-2). ).

If the preceding vehicle 11 is present, the control computer 10 subsequently determines whether or not the preceding vehicle 11 is present within a predetermined inter-vehicle distance corresponding to the current speed of the vehicle 2 (S-3). ). If the preceding vehicle 11 is out of the predetermined inter-vehicle distance, control according to the movement of the preceding vehicle is not necessary, so that the attitude control is not performed, and the normal traveling state as shown in FIG. It returns to S-1. In this normal traveling state, the vehicle 2 is substantially parallel to the road surface 12, and the direction of the laser beam 3a emitted from the laser radar 3 is also substantially parallel to the road surface 12, so that the laser radar 3 It is ready to be caught.

When the preceding vehicle 11 is within the predetermined inter-vehicle distance, the control computer 10 subsequently determines from the time change of the inter-vehicle distance L whether or not the relative speed between the vehicle 2 and the preceding vehicle 11 is substantially zero. (S-4). If the relative speed is almost 0, the normal running state is maintained, and the process returns to the initial step S-1. On the other hand, if the relative speed is not almost 0,
The acceleration of the front vehicle 11 is calculated from the change in the own vehicle speed and the inter-vehicle distance, and it is determined whether or not the front vehicle 11 is accelerating at a predetermined value or more (S-5).

When the preceding vehicle 11 is accelerating at a predetermined value or more and the inter-vehicle distance L is steadily increasing, it is estimated that the own vehicle 2 accelerates following the preceding vehicle 11. And
Based on this estimation, anti-squat control is performed in the active suspensions 4 and 5 to perform vehicle attitude control so that the attitude of the vehicle 2 with respect to the road surface 12 does not change (S-6).

Here, this anti-squat control is a control for suppressing the vehicle 2 from lowering during acceleration as shown in FIG. 3 (B). The damping force is increased to prepare for acceleration of the vehicle 2, and when acceleration is detected from a detection value from the acceleration sensor 8, the strokes of the front and rear active suspensions 4 and 5 are controlled. That is, the front suspension F is reduced and the rear suspension R
The active suspensions 4 and 5 are controlled so as to extend. Therefore, a change in the attitude of the vehicle 2 can be suppressed, and an erroneous acquisition of the laser radar 3 can be prevented. Further, since this control is performed by feedforward and feedback control based on the detection values of the stroke sensors 6 and 7, the vehicle attitude control is reliably performed.

If the preceding vehicle 11 is not accelerating at a predetermined value or more, the control computer 10 subsequently proceeds to the preceding vehicle 1.
It is determined whether 1 is equal to or more than a predetermined value and the vehicle is decelerating (S-7),
As a result, when the vehicle is not decelerating at the predetermined value or more, the normal traveling state is maintained, and the process returns to step S-1.

When the preceding vehicle 11 is decelerating at a predetermined value or more and the inter-vehicle distance L is gradually decreasing, anti-dive control is performed so that the attitude of the vehicle 2 with respect to the road surface 12 does not change. Carry out vehicle attitude control (S-
8).

This anti-dive control, contrary to the above-mentioned anti-squat control, is a control for suppressing the vehicle 2 from turning forward during deceleration as shown in FIG. In order to prepare for deceleration of the vehicle 2 by increasing the spring constant and damping force of the vehicle suspension 5, the front suspension F is extended and the rear suspension R is contracted by controlling the strokes of the front and rear active suspensions 4 and 5 at the time of deceleration. That is, in this case, since the inter-vehicle distance L decreases, it is predicted that the vehicle 2 will decelerate and change its attitude.
The attitude control is performed before deceleration. by this,
A change in the attitude of the vehicle 2 can be suppressed, and an erroneous acquisition of the laser radar 3 can be prevented. Then, after the attitude control by the anti-squat control or the anti-dive control, the process returns to the initial step S-1.

On the other hand, in step S-2, the forward vehicle 1
1 is determined not to exist, that is, the laser radar 3
If the vehicle can no longer catch the vehicle 11 ahead, the control computer 10 immediately sends the vehicle 2
It is determined whether the vehicle exists within a predetermined inter-vehicle distance corresponding to the current speed of the vehicle (S-9). Then, if the preceding vehicle 11 did not exist in the predetermined range immediately before, the preceding vehicle 11 did not originally exist, and the vehicle attitude control according to the movement of the preceding vehicle 11 is unnecessary. It returns to step S-1. Also, immediately before the vehicle 11
Is within the predetermined range, it is determined that the preceding vehicle 11 has been lost. For this reason, it is determined from the detection value of the acceleration sensor 8 whether the acceleration in the left-right direction is equal to or greater than a predetermined value, and whether the vehicle 2 is traveling on a curve is determined (S-1).
0). If the vehicle is traveling on a curve, it is determined that this is the cause of the inability to be captured, and the first step S
Returning to -1, if the vehicle is not traveling on a curve, it is subsequently determined from the front and rear stroke sensors 6, 7 whether or not the posture of the vehicle 2 is currently horizontal (S-11). If it is horizontal, it is determined that there is another cause that the image cannot be captured, and the process returns to the first step S-1.

When it is determined that the attitude of the vehicle 2 is not horizontal, it is determined that this is the cause of losing sight of the preceding vehicle 11, and by controlling the strokes of the front and rear active suspensions 4, 5, the front suspension F and the rear suspension are controlled. Attitude control is performed so that the attitude of the vehicle 2 is horizontal by equalizing the suspension R (S-12). afterwards,
It returns to the first step S-1.

As described above, the vehicle attitude control apparatus predicts a change in the attitude of the vehicle 2 due to acceleration / deceleration by using the inter-vehicle distance detecting function of the laser radar 3 with respect to the vehicle in front of the vehicle 2. The attitude of the laser radar 3 is controlled so as to be always constant with respect to the road surface 12 to prevent the laser radar 3 from being erroneously captured. Even when the preceding vehicle 11 does not exist, the posture of the vehicle 2 during traveling may be controlled by the stroke sensors 6 and 7 and the active suspensions 4 and 5 so that the posture of the vehicle 2 with respect to the road surface 12 is always constant.

[0027]

As described above, according to the vehicle attitude control apparatus of the present invention, the vehicle attitude is always kept constant with respect to the road surface in response to a dynamic attitude change due to acceleration and deceleration during running of the vehicle. Therefore, it is possible to prevent the laser radar from being erroneously captured. As a result, the inter-vehicle distance control function using the laser radar can be operated in a stable state, and the riding comfort is improved.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a vehicle attitude control device according to the present invention.

FIG. 2 is a flowchart of attitude control by a vehicle attitude control device.

FIGS. 3A, 3B, and 3C are explanatory diagrams of attitude control by a vehicle attitude control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle attitude control apparatus 2 Vehicle 3 Laser radar 4, 5 Active suspension 6, 7 Stroke sensor 8 Acceleration sensor 9 Speed sensor 10 Control computer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60G 17/015 B60T 8/24 G08G 1/09 G08G 1/16

Claims (1)

(57) [Claims] An inter-vehicle distance sensor for detecting an inter-vehicle distance between a preceding vehicle and a host vehicle, a speed sensor for detecting a speed of the host vehicle, and adjusting a relative position or movement of a vehicle body and wheels of the host vehicle. , Anchisuku when the vehicle position adjustment means for controlling the vehicle posture, to predict the acceleration and deceleration of the vehicle from the speed detected by the vehicle distance and the speed sensor detected by the inter-vehicle distance sensor, predicted that the own vehicle accelerates
When the vehicle control is performed and the vehicle is predicted to decelerate
Control means for controlling the vehicle attitude adjusting means so as to perform anti-dive control .