JP3087601B2 - Attitude control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to attitude control device for a vehicle, about the attitude control system, particularly that by the active suspension.

[0002]

2. Description of the Related Art A change in the attitude of a vehicle body when the vehicle travels has a great effect on steering stability and riding comfort. The causes of the change in the posture of the vehicle body include those due to driving / braking torque, those due to inertial force, those due to aerodynamic resistance and weather wind. The active suspension independently controls the internal pressure of the air springs that support the vehicle body, and maintains the posture of the vehicle body horizontally with respect to the road surface to improve ride comfort and steering stability. It was done.

In attitude control, the inner pressure of the air spring of the outer wheel is increased at the time of cornering to reduce the roll amount to control the attitude in the left-right direction (roll control). By increasing the pressure of the air spring to reduce the sinking at the rear of the vehicle body, increasing the internal pressure of the air spring of the front wheel during braking, and reducing the pressure of the air spring of the rear wheel to reduce the sinking at the front of the vehicle body during braking The attitude in the front-rear direction is controlled (anti-dive control), and the internal pressure of the air spring is controlled according to the vehicle height fluctuation to reduce the pitching housing (pitching housing control).

As shown in FIG. 4, the vehicle body 1 is controlled to have a mass of m, a front actuator of the body 1 (spring force of an air spring) F1 and a rear actuator force as shown in FIG. If (the spring force of the air spring) is F2, the inertial force at the center of gravity G is F (= mα), the height of the center of gravity G from the road surface is h, and the wheelbase is L, the acceleration α of the vehicle body 1 is detected. The generated forces F1, F2 of the front actuator and the rear actuator are controlled so that F1 = -mαh / L F2 = mαh / L, so that the posture of the vehicle body 1 in the front-rear direction is kept constant.

[0005]

However, in the above-described attitude control in the longitudinal direction of the vehicle body, the attitude cannot be controlled when the acceleration α is zero because the acceleration α of the vehicle body is detected and controlled. In an actual vehicle, acceleration may not be generated due to road surface resistance or aerodynamic resistance even when driving torque acts on driving wheels. In such a case, the conventional control method cannot keep the posture of the vehicle body constant. Also, in the case of deceleration due to aerodynamic resistance or speed increase due to tailwind, there is also a problem that the posture changes as a change in acceleration.

As a vehicle body attitude control method, for example, there is a vehicle suspension device disclosed in Japanese Utility Model Laid-Open Publication No. 64-103524. This device supplies fluid to the front wheel side suspension unit when the deceleration becomes equal to or more than a first set value within a set time after depressing the brake, and discharges fluid from the rear wheel side when the deceleration becomes equal to or more than a second set value after the set time. Thus, anti-nose dive control is performed.

However, this control device only controls the longitudinal direction of the vehicle body during braking. When the acceleration α is 0, the vehicle body moves forward and backward during deceleration due to aerodynamic resistance and acceleration due to tailwind. Nothing is done about the attitude control of the direction. The present invention has been made in view of the above, performs always the vehicle body attitude control regardless of the running condition of the vehicle, providing attitude control device designed to reduce the front-rear direction of a change in the posture of the vehicle body The purpose is to:

[0008]

[0009]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
According to the present invention, in a posture control device that detects the acceleration in the front-rear direction of a vehicle body, controls the generated force of a front actuator and the generated force of a rear actuator, and keeps the posture of the vehicle body constant in the front-rear direction. A connection member that connects the drive side and the vehicle body side and receives a force acting in the front-rear direction of the vehicle body, and a detection unit that detects a force acting on the connection member,
Control means for controlling the generated force of each of the front and rear actuators based on the detection result of the detection means.

[0010]

[0011]

By the action] drive dynamic side and connects the vehicle body side detection means provided on the connecting member for receiving a force acting in the longitudinal direction of the vehicle body to detect a force acting in the longitudinal direction of the vehicle body, control means, this The front and rear attitudes of the vehicle body are controlled by controlling the generated forces of the front and rear actuators based on the result detected by the detection means.

[0012]

Examples of posture control device EXAMPLES Hereinafter the present invention will be described. FIG. 1 shows an outline of a vehicle for carrying out the present invention. A vehicle body 1 is supported by an axle of a front wheel 2 and a rear wheel 3 by a front actuator and a rear actuator, for example, an air spring (both not shown). . The rear wheel 3 is a drive wheel. As shown in FIG. 2, the axle housing 4 of the rear wheel 3 is supported by a vehicle body frame 7 by an appalladias rod 5 and a lower radial rod 6.

That is, the appalladias rod 5 and the lower radius rod 6 are arranged in parallel in the front-rear direction of the vehicle body and in a line up and down, and the rear ends 5 a and 6 a are located above the axle center O of the axle housing 4. The front ends 5b and 6b are rotatably supported by brackets 8 vertically provided on the vehicle body frame 7, respectively.
And from the axle center O to the Appalladias rod 5,
The distance to the rear ends 5a and 6a of the lower radial rod 6 is
They are a and b, respectively. The wheel base is L.

The vehicle body 1 is provided with an acceleration sensor 10 for detecting the acceleration of the vehicle body 1 in the front-rear direction. The appalladia rod 5 and the lower radial rod 6 are sensors for detecting stress acting on the vehicle body 1, for example, a strain sensor. Gauge 1
1, 12 are attached. The control device 13 controls the generated force (spring force of the air spring) of the front actuator and the rear actuator based on the signals input from the acceleration sensor 10 and the strain gauges 11 and 12 to control the longitudinal direction of the vehicle body 1. Perform attitude control.

The attitude control method will be described below with reference to the flowchart of FIG. Let m be the mass of the vehicle body 1 and F be the force generated by the front and rear actuators, respectively.
1, F2, the inertial force acting on the center of gravity G of the vehicle body is F (= m
α), the aerodynamic force acting on the aerodynamic center Q of the vehicle body is F3, and the height from the axle center O to the center of gravity G, the aerodynamic center Q is h, respectively.
1, h2, the driving / braking force acting on the vehicle body 1 is F4,
The moment acting on the vehicle body 1 in the front-rear direction due to the braking torque is T, and the acceleration acting on the vehicle body 1 in the front-rear direction is α.

The control device 13 receives signals from the acceleration sensor 10 and the strain gauges 11 and 12 and receives longitudinal signals α acting on the vehicle body 1 and stresses σ 1 acting on the appalladias rod 5 and the lower radial rod 6. σ2 is obtained (steps S1, S2, S3 in FIG. 3). Next, the stress σ
The driving / braking force F4 acting on the vehicle body 1 and the moment T acting on the vehicle body based on the driving / braking torque are calculated from 1, σ2 (step S4). Assuming that the sectional areas of the Appalladias rod 5 and the lower radial rod 6 are A1 and A2, the forces acting on the Appalladias rod 5 and the lower radial rod 6 (the forces acting in the front-rear direction of the vehicle body 1) P1 and P2 are P1
= Σ1A1, P2 = σ2A2.

Accordingly, the driving / braking force F4 acting in the longitudinal direction of the vehicle body 1 and the moment T acting in the longitudinal direction of the vehicle body by the driving / braking torque are as follows: F4 = P1 + P2 (1) T = bP2-aP1 (2) Becomes

Next, the control device 13 calculates the longitudinal acceleration α of the vehicle body 1 calculated in step S1 and the driving / braking force F4 acting in the longitudinal direction of the vehicle body 1 calculated in step S4.
Then, the generated force F2 of the rear actuator and the generated force F1 of the front actuator are obtained from the moment T acting on the vehicle body 1 in the front-rear direction by the driving / braking torque (step S5). The inertial force F acting on the center of gravity G of the vehicle body 1 is F = mα, and the aerodynamic force F acting on the aerodynamic center Q
3 becomes F3 = F4−mα. Therefore, the moment M1 acting in the front-rear direction of the vehicle body 1 by the inertial force F is M1 = m
αh1, and the moment M2 acting in the front-rear direction of the vehicle body 1 by the aerodynamic F3 is M2 = (F4−mα) h2.

Therefore, the generated force F of the rear actuator
2. The generated force F1 of the front actuator is as follows: F2 = (M1 + M2 + T) / L = {mαh1 + (F4-mα) h2 + T} / L (3) F1 = −F2 (4)

The controller 13 controls these actuators so that the force generated by the rear actuators becomes F2 and the force generated by the front actuators becomes F1. Accordingly, the control device 13 can suppress a change in the posture of the vehicle body 1 in the front-rear direction even under conditions such as acceleration, deceleration, constant speed, road surface resistance, strong wind, presence or absence of a gust, and the like.

From the equations (3) and (4), when the height h2 of the aerodynamic center Q and the height h1 of the center of gravity G are substantially equal, F2 = (F4h2 + T) / L (5) The sensor 10 becomes unnecessary. Therefore, the cost can be reduced by the price of the acceleration sensor.

[0022]

[0023]

As described above, according to the present invention, a connecting member for connecting a drive side and a vehicle body side and receiving a force acting in the front-rear direction of the vehicle body, and a detecting member for detecting a force acting on the connecting member. Means and control means for controlling the generated force of each of the front and rear actuators based on the detection result of the detection means, thereby simplifying the configuration of the attitude control device, which is simpler than that of a conventional vehicle. And the device can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a vehicle to which the engagement Ru posture control apparatus according to the present invention.

FIG. 2 is an explanatory diagram of a force acting on the vehicle body from the drive wheels in FIG.

FIG. 3 is a flowchart illustrating an example of a control procedure of the attitude control device of the present invention.

FIG. 4 is an explanatory diagram of a conventional vehicle attitude control method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 2 Front wheel 3 Rear wheel (drive wheel) 4 Axle housing 5 Appalladias rod 6 Lower radius rod 7 Body frame 8 Bracket 10 Acceleration sensor 11, 12 Strain gauge 13 Control device

Claims (3)

(57) [Claims] 1. A posture control device for detecting the acceleration of a vehicle body in the front-rear direction and controlling the generated force of a front actuator and the rear actuator to maintain a constant posture of the vehicle body in a front-rear direction. A connecting member that connects the vehicle body side and the vehicle body side and receives a force acting in the front-rear direction of the vehicle body, a detecting unit that detects a force acting on the connecting member, and a front and a rear based on a detection result of the detecting unit. A control device for controlling the force generated by each actuator. Wherein said connecting member is in claim 1, characterized in that the <br/> radians slot de disposed parallel to the up and down with respect to the axle center of and the drive shaft in the longitudinal direction of the vehicle body The attitude control device as described in the above. Wherein said detecting means includes attitude control device according to claim 1 or 2, characterized in that a strain gauge.