JP3052995B2 - Suspension 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 an apparatus for controlling the attitude of a vehicle body by using an active suspension.

[0002]

2. Description of the Related Art In order to reduce the roll of a vehicle body when the vehicle is turning, a so-called active suspension is used to adjust the height of the vehicle body in the front, rear, left and right directions by means of fluid pressures supplied to actuators of the left, right and front and rear wheel suspensions. As exemplified in JP-A-125616, a technique for adding a control amount corresponding to a lateral acceleration acting on a vehicle body at the time of turning a vehicle to an active suspension has been conventionally known, and a roll control response generated at the time of vehicle steering. In consideration of the delay in the performance, there is also known a technique in which the control amount is determined based on the lateral acceleration calculated from the steering angle and the vehicle speed in the initial stage of steering. No consideration was given to maintaining the relationship properly and exerting the performance of the tire sufficiently.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to improve the performance of a vehicle by always maintaining the relationship between the tires of the vehicle and the road surface properly by using an active suspension in the vehicle.

[0004]

According to the present invention, there is provided a suspension control apparatus according to the present invention, wherein a first means for detecting a running speed of a vehicle, a second means for detecting a steering angle of the vehicle, Third means for detecting the actual lateral acceleration of the vehicle, fourth means for calculating a lateral acceleration acting on the vehicle based on the vehicle speed detected by the first means and the steering angle detected by the second means, Fifth means for estimating the amount of lateral movement of the center of gravity of the vehicle from the actual lateral acceleration detected by the third means or the lateral acceleration calculated by the fourth means, and the lateral movement of the center of gravity estimated by the fifth means A first control means for determining a suspension control amount for canceling the roll of the vehicle from the amount, a sixth means for estimating a camber angle change of the vehicle from the actual lateral acceleration detected by the third means, A second control means for determining a suspension control amount for canceling the camber angle change estimated by the six means, and a second suspension control amount for outputting a final suspension control amount based on the suspension control amounts from the two control means. And three control means for controlling the camber angle of the vehicle to be substantially zero.

That is, the camber angle change is estimated by the sixth means from the actual lateral acceleration detected by the third means, and the second control means determines a suspension control amount for canceling the camber angle change. The first control means determines a suspension control amount for canceling the roll of the vehicle from the lateral movement amount of the center of gravity of the vehicle estimated by the fifth means, and the third control means determines the final suspension control amount based on the two suspension control amounts. Is output to control the vehicle's camber angle to the ground to be almost zero, so that even if a lateral force is actually applied to the tire, the change in the camber angle specific to the vehicle corresponding to the lateral force is surely ensured. By suppressing, the ground camber angle of the vehicle is kept almost zero,
The relationship between the tire and the road surface can always be made appropriate.

According to a second aspect of the present invention, there is provided a suspension control apparatus for detecting a traveling speed of a vehicle.
Means, a second means for detecting the steering angle of the vehicle, a third means for detecting the actual lateral acceleration of the vehicle, and a vehicle speed detected by the first means and a steering angle detected by the second means. Fourth means for calculating the lateral acceleration acting on the vehicle, and fifth means for estimating the amount of lateral movement of the center of gravity of the vehicle from the actual lateral acceleration detected by the third means or the lateral acceleration calculated by the fourth means. Means, a first control means for determining a suspension control amount for canceling the roll of the vehicle based on the lateral movement amount estimated by the fifth means, a camber angle of the vehicle from the steering angle detected by the second means Sixth means for estimating the change, second control means for determining a suspension control amount for canceling the camber angle change estimated by the sixth means, and
A third control unit that outputs a final suspension control amount based on the suspension control amounts from the two control units, and controls the vehicle so that the ground camber angle of the vehicle becomes substantially zero.

That is, the camber angle change is estimated by the sixth means from the steering angle detected by the second means, and the second control means determines a suspension control amount for canceling the camber angle change. The first control means determines a suspension control amount for canceling the roll of the vehicle from the lateral movement amount of the center of gravity of the vehicle estimated by the five means,
The third control means outputs the final suspension control amount based on the two suspension control amounts, so that the ground camber angle of the vehicle is controlled to be substantially zero. By reliably suppressing the change in the camber angle, the camber angle with respect to the ground of the vehicle can be maintained at substantially zero, and the relationship between the tire and the road surface can always be made appropriate.

Further, the suspension control apparatus according to the present invention includes a first means for detecting a traveling speed of the vehicle, a second means for detecting a steering angle of the vehicle, and a real lateral acceleration of the vehicle. A third means for detecting, and a fourth means for calculating a lateral acceleration acting on the vehicle based on the vehicle speed detected by the first means and the steering angle detected by the second means.
A fifth means for estimating the amount of lateral movement of the center of gravity of the vehicle from the actual lateral acceleration detected by the third means or the lateral acceleration calculated by the fourth means; First control means for determining a suspension control amount for canceling the roll of the vehicle from the amount of lateral movement of the center of gravity; sixth means for estimating a change in camber angle of the vehicle from the actual lateral acceleration detected by the third means; Seventh means for estimating a camber angle change of the vehicle from the steering angles detected by the two means, the sixth means and the seventh means.
Means for determining a suspension control amount for canceling the change in camber angle of the vehicle estimated by the means, and outputting a final suspension control amount based on the suspension control amounts from both control means. And controls the vehicle so that the ground camber angle of the vehicle becomes substantially zero.

That is, the camber angle change is estimated by the seventh means from the steering angle detected by the second means, and the camber angle change is estimated by the sixth means from the actual lateral acceleration detected by the third means. The second control means determines a suspension control amount for canceling the camber angle change, and the first control means determines a suspension control amount for canceling the roll of the vehicle from the lateral center of gravity movement of the vehicle estimated by the fifth means at the time of turning the vehicle. Is determined, and the third control means outputs the final suspension control amount based on the two suspension control amounts, so that the ground camber angle of the vehicle is controlled to be substantially zero. By reliably suppressing the change in the camber angle specific to the corresponding vehicle, the camber angle to the ground of the vehicle is maintained at almost zero,
The relationship between the tire and the road surface can always be made appropriate.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention shown in the drawings will be described below. In FIG. 1, hydraulic oil in a reservoir tank 1 mounted on a vehicle is sucked up by an oil pump 2 through an oil passage 3 and discharged to the oil passage 4 as pressure oil. 4F and rear wheel side oil passage 4R
And the oil passages 4F, 4R are further branched into left and right wheel oil passages 4FL, 4FR, 4RL, and 4RR, respectively, to suspension units 5FL, 5FR, 5RL, and 5RR provided on the front, rear, left, and right wheels, respectively. It is connected.

Each suspension unit 5FL, 5F
R, 5RL and 5RR each have the same structure, and therefore, as a representative, the left front wheel suspension unit 5F
To explain L, a suspension spring 6 and a single-acting hydraulic actuator 7 are provided between the vehicle body and the wheels, and an oil passage 8 communicating with a hydraulic chamber of the hydraulic actuator 7 is provided via a control valve 9 which is a proportional solenoid valve. To the oil passage 4FL and the return oil passage 10.

The pilot oil pressure in the pilot oil pressure chamber for controlling the opening and closing of the control valve 9 is adjusted by the amount of pressure oil flowing from the pilot oil passage 11 branched from the oil passage 4FL to the return oil passage 10 via the oil passage 12 and this oil pressure. The amount of pressure oil is controlled in accordance with the control current from the controller 14. As a result, the opening of the control valve 9 is adjusted by the control current from the controller 14, and the hydraulic pressure in the hydraulic chamber of the hydraulic actuator 7 is controlled by the controller 14. It is controlled so as to be proportional to the current value.

An accumulator 15 filled with gas is connected to the oil passage 8 via a throttle 16, and the accumulator 15 is configured to perform a gas spring action and a vibration damping action.

On the other hand, a relief oil passage 17 connecting the oil passage 4 and the return oil passage 10 is provided with a relief valve 18.
When the discharge oil pressure of the oil pump 2 exceeds a predetermined value, the relief valve 18 opens, and hydraulic oil is returned from the oil passage 4 to the reservoir tank 1.

The controller 14 includes a vehicle speed sensor 20 for detecting a vehicle speed V, a steering angle sensor 21 for detecting a steering angle θ of a steering wheel of the vehicle, and an actual lateral acceleration acting on the vehicle body in the left-right direction. Each detection signal is sent from the lateral acceleration sensor 22 for detecting G, and based on these detection signals, the controller 14 controls each control valve 9 individually as described later, and controls the suspension units 5FL, 5FR for each wheel. , 5RL and 5R
By independently controlling the stroke and spring constant of R,
Vehicle height adjustment and vehicle body posture control can be performed.

Next, the control operation of the controller 14 will be described. When the vehicle is traveling, that is, when the vehicle speed sensor 20
Has detected the vehicle speed V> 3 km / h, the controller 14 having received the detection signal starts the control action shown in the control block diagram of FIG. 2, and the steering angular velocity dθ / dt> 1
In the case of 5 ° / sec, the lateral acceleration Go acting on the vehicle body is calculated from the vehicle speed V and the steering angle θ, and the lateral displacement w of the center of gravity of the vehicle body is estimated from the lateral acceleration Go based on the vehicle specifications. By estimating the center-of-gravity lateral movement amount w from the lateral acceleration Go,
There is no time delay in estimating the amount of lateral movement w of the center of gravity at the beginning of steering, during sudden steering, or the like.

When the steering angular velocity dθ / dt ≦ 15 ° / sec, that is, when the steering angular velocity dθ / dt is small and the time lag in detecting the actual lateral acceleration G is small, or
When the actual lateral acceleration G is acting on the running vehicle body irrespective of the presence or absence of the steering due to the side wind, the inclination of the road surface, the trace of the road surface, etc., the center of gravity of the vehicle body is calculated from the actual lateral acceleration G based on the vehicle specifications. The lateral movement amount w is estimated.

Further, the suspension units 5FL, 5FR, and 5RL are used to cancel the roll generated on the vehicle body in accordance with the lateral movement amount w of the center of gravity of the vehicle body estimated as described above.
And 5RR, the control current Io to the control valve 9 for controlling the attitude of the vehicle body is read from the value of the center-of-gravity lateral movement amount w in the map 30.

On the other hand, the lateral force F acting on the tire is calculated from the actual lateral acceleration G detected by the lateral acceleration sensor 22, and the camber angle change Ky predicted to be caused by the lateral force F is obtained by actual measurement. The camber angle change Kh, which is read from the value of the lateral force F based on the map 31 and is predicted to be generated from the steering angle θ detected by the steering angle sensor 21, is calculated based on the map 32 obtained by actual measurement. Is read from the value of

Next, the camber angle change Ky and the camber angle change Kh are added, and the suspension unit 5FL,
By controlling 5FR, 5RL and 5RR, the added value R
Is read from the value of the added value R in the map 33, and the final control current I which is the sum of the control current Io and the control current IR, that is, Then, a vehicle roll control amount signal is output from the controller 14 to the control valve 9.

Accordingly, each control valve 9 is individually controlled by the control current I, and the suspension units 5FL, 5FR, 5RL, and 5RR for each wheel are independently controlled, so that the camber angle to ground is always zero. Because the suspension can be controlled, the relationship between the tires and the road surface is properly maintained regardless of the running conditions, and the tires can be used to improve the cornering performance of the vehicle, improve the braking performance, improve the steering feeling, etc. By sufficiently exhibiting the possessed performance, it is possible to surely improve the vehicle performance.

Further, since control is performed such that the camber angle to the ground is given priority to zero rather than the change in roll attitude of the vehicle body to zero, uneven wear of the tire can be easily reduced. When the vehicle is traveling at high speed, a relatively large actual lateral acceleration G occurs even with a small steering angle θ. However, the negative camber effect due to the steering angle θ is small because the steering angle θ is small. Since the roll of the camber angle is relatively large and the camber angle change is relatively large, by canceling the camber angle change and setting the camber angle to the ground to zero, the vehicle body eventually has a gentle reverse roll posture, and Since the negative camber effect due to the steering angle θ is large at large low-speed steering angles, the ground camber angle should be zero even if the roll control amount is relatively small. It can be, there is an advantage that handling characteristics with a sense of security can be obtained.

[0023]

In the suspension control device according to the present invention, the camber angle of the vehicle is controlled so as to be substantially zero, so that even if a lateral force is actually applied to the tire, the suspension control device can respond to the lateral force. By reliably suppressing the change in the camber angle inherent to the vehicle, the camber angle to the ground of the vehicle can be maintained at almost zero, and the relationship between the tires and the road surface can always be made appropriate regardless of the running conditions. The performance possessed by the tire, such as the improvement of the turning limit performance of the vehicle, the improvement of the braking performance, and the improvement of the steering feeling, can be sufficiently exhibited.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram in an embodiment of the present invention.

FIG. 2 is a control block diagram of the embodiment.

[Explanation of symbols]

 2 Oil pump 7 Hydraulic actuator 9 Control valve 14 Controller 20 Vehicle speed sensor 21 Steering angle sensor 22 Lateral acceleration sensor 30, 31, 32, 33 Map

Continuation of the front page (56) References JP-A-4-232113 (JP, A) JP-A-3-157215 (JP, A) JP-A-5-178057 (JP, A) JP-A-4-243612 (JP) , A) JP-A-3-125616 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60G 17/015

Claims (3)

(57) [Claims] A first means for detecting a traveling speed of the vehicle; a second means for detecting a steering angle of the vehicle; a third means for detecting an actual lateral acceleration of the vehicle; a vehicle speed detected by the first means Fourth means for calculating a lateral acceleration acting on the vehicle based on the steering angle detected by the second means and the actual lateral acceleration detected by the third means or the lateral acceleration calculated by the fourth means. Fifth means for estimating the lateral displacement of the center of gravity of the vehicle from acceleration, first control means for determining a suspension control amount for canceling the roll of the vehicle from the lateral displacement of the center of gravity estimated by the fifth means, Sixth means for estimating the camber angle change of the vehicle from the actual lateral acceleration detected by the means, and a suspension control amount for canceling the camber angle change estimated by the sixth means. A second control means for determining, and a third control means for outputting a final suspension control amount based on each of the suspension control amounts from the two control means, and the camber angle to the ground of the vehicle becomes substantially zero. Control device to control the suspension. 2. A first means for detecting a traveling speed of the vehicle, a second means for detecting a steering angle of the vehicle, a third means for detecting an actual lateral acceleration of the vehicle, and a vehicle speed detected by the first means. Fourth means for calculating a lateral acceleration acting on the vehicle based on the steering angle detected by the second means and the actual lateral acceleration detected by the third means or the lateral acceleration calculated by the fourth means. Fifth means for estimating the amount of lateral movement of the center of gravity of the vehicle from acceleration, first control means for determining a suspension control amount for canceling the roll of the vehicle from the amount of lateral movement of the center of gravity estimated by the fifth means, and the second means Sixth means for estimating a camber angle change of the vehicle from the steering angle detected by the means, and determining a suspension control amount for canceling the camber angle change estimated by the sixth means. And a third control means for outputting a final suspension control amount based on each of the suspension control amounts from the two control units, so that the camber angle to the ground of the vehicle becomes substantially zero. Suspension control device to control. 3. A first means for detecting a running speed of the vehicle, a second means for detecting a steering angle of the vehicle, a third means for detecting an actual lateral acceleration of the vehicle, and a vehicle speed detected by the first means. Fourth means for calculating a lateral acceleration acting on the vehicle based on the steering angle detected by the second means and the actual lateral acceleration detected by the third means or the lateral acceleration calculated by the fourth means. Fifth means for estimating the lateral displacement of the center of gravity of the vehicle from acceleration, first control means for determining a suspension control amount for canceling the roll of the vehicle from the lateral displacement of the center of gravity estimated by the fifth means, A sixth means for estimating a change in camber angle of the vehicle from the actual lateral acceleration detected by the means, and a seventh means for estimating a change in camber angle of the vehicle from the steering angle detected by the second means. A second control means for determining a suspension control amount for canceling a change in the camber angle of the vehicle estimated by the sixth means and the seventh means, and the suspension control amounts from the two control means. And a third control unit that outputs a final suspension control amount based on the control signal, and controls the vehicle so that a camber angle to the ground is substantially zero.