JPH0771887B2 - Control device for vehicle height adjustable suspension - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for a vehicle height adjustable suspension, and in particular,
The present invention relates to a control device for a vehicle height adjusting suspension configured to control the supply / discharge amount of working fluid to / from a vehicle height adjusting actuator by a solenoid valve.

(Prior Art) There is known a vehicle height adjustable suspension capable of appropriately performing both steering stability of a vehicle and improvement of riding comfort.

In this vehicle height adjusting suspension, a vehicle height adjusting actuator is mounted between a sprung body and an unsprung body of the vehicle body, and the hydraulic fluid adjusting valve is used to control the supply / discharge amount of the working fluid to / from the vehicle height adjusting actuator. Operates to adjust vehicle height.

The hydraulic adjusting valve of this type of vehicle height adjusting suspension is switched by the control means to increase or decrease the pressure value of the working fluid applied to the vehicle height adjusting actuator in the circuit, and the vehicle height adjusting actuator is operated according to the pressure value. Adjusting the increase and decrease of vehicle height.

Among such vehicle height adjustable suspensions, especially the sixth
As shown in the figure, a control means 101 is connected to a solenoid valve 100 as a hydraulic pressure control valve, and the control means 101 duty-operates the solenoid valve 100 to increase or decrease the fluid pressure depending on its duty ratio. It is known that the vehicle height adjusting actuator is configured to increase or decrease the vehicle height.

The control means 101 here receives the actual vehicle height signal from the vehicle height sensor 102 and the target vehicle height information from the target vehicle height setting means 103, and outputs a vehicle height control signal based on both signals. The duty control circuit 106 with the oscillator 105 outputs a duty current having a duty ratio corresponding to the vehicle height control signal, and the drive circuit 107 outputs a drive current corresponding to the duty current to the solenoid valve 100. It is configured.

The solenoid valve 100 increases or decreases the pressure value of the working fluid applied to the vehicle height adjustment actuator in the circuit, and automatically adjusts the vehicle height to the vehicle height according to the target vehicle height information.

(Problems to be solved by the invention) By the way, the vehicle height control signal calculation circuit 104 in this control means
In consideration of the fact that the current actual vehicle height signal constantly fluctuates due to the vertical movement of the wheels, an averaging filter circuit 108 is attached, whereby the actual vehicle height data within a predetermined time is averaged, and the average value is calculated. It is used as vehicle height data to adjust vehicle height.

In this way, the averaging filter circuit 108 used has a relatively large time constant because it is necessary to average the vehicle height data. For this reason, when the vehicle body roll angle that occurs immediately after the steering wheel of the vehicle is reduced, that is, when the zero roll adjustment is performed, this actual vehicle height change is not incorporated into the target vehicle height signal with high responsiveness, which is a problem.

It is an object of the present invention to provide a vehicle height adjusting suspension control device capable of adjusting the vehicle height with good responsiveness.

(Means for Solving the Problem) In order to achieve the above-mentioned object, a control device for a vehicle height adjusting suspension according to the present invention controls the intake and exhaust amount of working fluid to and from a vehicle height adjusting actuator provided on each wheel. Operated by a solenoid valve, the control means of the solenoid valve detects a deviation between the commanded target vehicle height signal and the actual vehicle height signal from the vehicle height sensor, and outputs a control signal corresponding to the deviation to the solenoid valve. In the control device of the vehicle height adjusting suspension for holding the vehicle at the target vehicle height, the turning state detecting means provided in the vehicle for detecting the turning state of the vehicle, the vehicle based on the detection signal of the vehicle height sensor. The deviation from the target vehicle height and the speed of change of each vehicle height adjusting actuator caused by the roll of the vehicle are derived, and the turning state detecting means performs the steering operation at a predetermined steering angle or more. When detected, a deviation correction value set according to the deviation and a change speed correction value set according to the change speed are added to the control signal, and a correction value detection circuit for suppressing roll is provided. And

(Operation) This control means obtains a control signal corresponding to the deviation between the target vehicle height signal and the actual vehicle height signal, and drives the solenoid valve for operating the vehicle height adjusting actuator by the control signal,
In particular, based on the detection signal of the vehicle height sensor, the deviation from the target vehicle height and the changing speed of each vehicle height adjusting actuator caused by the rolling of the vehicle are derived, and the turning state detecting means controls the steering operation at a predetermined steering angle or more. When it is detected that a snake has been performed, the deviation correction value set according to the deviation and the change speed correction value set according to the change speed are corrected in addition to the control signal. As a result, the roll generated in the vehicle is suppressed.

(Example) FIG. 1 shows a main part of a control device for a vehicle height adjusting suspension as an example of the present invention. The vehicle height adjusting suspension control device is attached to each of the left, right, front, and rear wheels of the vehicle.

As shown in FIGS. 2 and 1, the vehicle height adjusting suspension includes a vehicle height adjusting actuator (hereinafter referred to as an actuator) 1 and a coil spring 3 for each wheel.
And a control unit 4 (first control unit) connected to the electromagnetic valve 2 for supplying and discharging the working fluid to and from the actuator 1 in the amount corresponding to the duty ratio.
In the figure, only the control means 4 _FL for the front left is shown). The control means 4 is the control means for the front left shown in the figure.
4 _FL , front right control means 4 _FR , rear left control means
4 _RL , control means 4 _RR for rear right (see FIG. 2), and these control means 4 _FL , 4 _FR , 4 _RL , 4 _RR are individually connected to the solenoid valve 2 of each wheel. Here, the front left control means 4 _FL shown in FIG. 1 will be mainly described.

The actuator 1 comprises a hydraulic cylinder 111 having one end connected to the sprung member 7 and a piston 112 having one end connected to the unsprung member 8 and having a sprung member 7 and an unsprung member 8. Is configured to support a vehicle load while allowing relative displacement of the vehicle body.

The solenoid valve 2 is a proportional solenoid valve used in the vehicle height adjusting hydraulic circuit 10 shown in FIG. 2, and its entire configuration is shown in FIG. That is, the solenoid valve 2 is connected to the pilot 11 and the main
It consists of 12 and. The pilot 11 is an oil passage 10 for adjusting the hydraulic pressure from the pump 13 to the pilot pressure, a poppet valve 14 for adjusting the high pressure oil from the pump to the pilot pressure, and a duty operation of the poppet valve 14 in response to the drive current from the control means 4 _FL. It is composed of a solenoid 15 and a solenoid. Main 12 is main body 16
A spool 17 that slides inside, a load pressure chamber 18 that applies load pressure from an actuator (hereinafter referred to as an actuator) 1 to one end of the spool 17, a pilot chamber 19 that applies pilot pressure to the spool 17, and a spool 17 are in a neutral position. In this case, a port 20 on the pump 13 side, a port 22 on the tank 21 side, and a load side port 24 that is in constant communication with the central chamber 23 of the spool 17 are formed.

In the case of such an electromagnetic valve 2, the spool 17 is held in the neutral position in a steady state where the load pressure and the pilot pressure do not fluctuate, and the spool 17 moves left and right when the load actuator moves and the load pressure decreases or increases. , The hydraulic oil is supplied / discharged, and the poppet valve 14 is duty-operated by the drive current from the control means 4 _FL . Based on the characteristics shown in FIG. Pressure can be output from load side port 24.

In FIG. 2, reference numeral 25 is a gas spring that acts as an interferometer when the load pressure suddenly increases, reference numeral 31 is a discharge passage, reference numeral 32 is a return passage, and reference numeral 33 is an excessive rise in discharge pressure.
Reference numeral 35 indicates a check valve, reference numeral 36 indicates an accumulator, reference numeral 37 indicates an oil cooler, and reference numeral 50 indicates a filter.

The control device 4 _FL includes a drive circuit 38, a correction circuit 39 as a correction value detection circuit that outputs a corrected vehicle height control signal to the drive circuit 38, a correction value calculation circuit 40 that outputs a correction value to the drive circuit 38, and a correction circuit.
A target vehicle height setting circuit 41 that outputs a vehicle height control signal to 39, and an analog switch 42 between the correction circuit 39 and the correction value calculation circuit 40.
And a turning state detecting means 43 as a turning state detecting means for controlling opening / closing of the.

The drive circuit 38 includes an oscillation unit and an amplification unit (not shown),
It is configured to generate a rectangular wave signal with a predetermined duty ratio based on the well-known PWM method (pulse width modulation method). A drive current is supplied to the amplifier section from a power supply circuit (not shown).

The target vehicle height setting circuit 41 includes a comparator 411, one input end of which receives a target vehicle height signal set by the target vehicle height setting means 44 through the buffer 45, and the other input end thereof receives the vehicle height. Receives the actual vehicle height signal from the sensor 46 via the buffer 47,
A vehicle height change signal Va, which is the difference between the actual vehicle height equivalent voltage of the vehicle height sensor and the neutral voltage Vc (set by the neutral voltage setting circuit 51), is output. The vehicle height change signal Va is provided with a smoothing circuit 412, which averages actual vehicle height data within a predetermined time and outputs a vehicle height control signal Va based on the average value.

The correction value calculation circuit 40 includes an adder 401 and a proportional circuit 402 and a differential circuit 403 connected to both input terminals of the adder 401, and the proportional circuit 402 uses the vehicle height signal Vp from the vehicle height sensor 46 as a neutral voltage Vc reference. Then, the differential circuit 403 calculates the differential value of the actual vehicle height signal, and outputs the differential signal Vd with the neutral voltage Vc as a reference. Then, the adder 401 outputs both of these signals, that is, the correction signal (Vp + Vd) which is the addition value of the deviation correction value and the change speed correction value.

The normally closed analog switch 42 is opened by the high H signal. The turning detection means 43 connected to this is an AND circuit.
431 equipped with a handle operation detection circuit 432 on both input ends
And a vehicle speed discrimination circuit 433 is connected.

The steering wheel operation detection circuit 432 is configured to receive a turning angle signal from the steering wheel angle sensor 48 and output a high H signal when the steering angle signal exceeds a predetermined value.

On the other hand, if the vehicle speed discrimination circuit 433 exceeds the set value, here 3 km / h, from the vehicle speed signal of the vehicle speed sensor 49,
It is configured to output a high H signal.

When the correction circuit 39 is in a steady state, that is, when the analog switch 42 is off, the added value Va of the neutral voltage Vc and the vehicle height control signal Va is
-Vc is the addition value Va- (Vp + V) of the correction signal (Vp + Vd) and the vehicle height control signal Va when the analog switch 42 is turned on.
Each of d) is output as a corrected vehicle height control signal.

When the vehicle height adjusting suspension control device is operated, a road surface reaction force is applied to each wheel, and accordingly, the actuator 1 and the coil spring 3 perform relative displacement between the sprung portion and the unsprung portion. Perform absorption operation. At the same time, a change occurs in the actual vehicle height information, a duty current for obtaining the target vehicle height set for each wheel is output from the drive circuit 38 to the solenoid valve 2, and the solenoid valve 2 causes the actuator 1 to receive the actuator pressure. By switching to an appropriate vehicle height, the vehicle height can be reduced to zero. In this case, in particular, as shown in FIG. 4, when the steering wheel angle is cut to a predetermined value or more during traveling, the target vehicle height signal set for each corner wheel is corrected to [Va- (Vp + Vd)]. The corrected vehicle height control signal [Va- (Vp + Vd)] suddenly increases from immediately after the steering wheel is operated, so that the corresponding solenoid valve 2 is operated with a drive current having a predetermined duty ratio with good responsiveness, and the appropriate actuator pressure is applied. The actuator 1 is actuated by the hydraulic pressure of (1) to adjust the vehicle height value (FIG. 4 shows the lower left front wheel lowering adjustment process inside the turning as an example), and the vehicle can be controlled to the zero roll position with good responsiveness.

(Effects of the Invention) As described above, the control device for a vehicle height adjusting suspension according to the present invention adjusts the vehicle height during normal operation and drives the solenoid valve that operates the vehicle height adjusting actuator during turning. The vehicle height control signal includes a deviation correction value that is set according to a deviation that is a displacement of the vehicle height adjustment actuator from the target vehicle height, and a change speed correction value that is set according to a changing speed that is a change rate of the displacement. To drive the solenoid valve. For this reason, the control signal can be corrected to a larger value as the deviation of the vehicle height adjusting actuator from the target vehicle height and the changing speed thereof are larger.
Especially for a sudden roll immediately after steering wheel operation, immediately enter zero roll control to suppress the roll of the vehicle body,
It is possible to control the vehicle body so that it can be responsively changed into a zero roll.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a main part of a control device for a vehicle height adjusting suspension as an embodiment of the present invention, FIG. 2 is a hydraulic circuit equipped with the same control device, and FIG. FIG. 4 is a sectional view of a solenoid valve, FIG. 4 is a waveform diagram for explaining the time-dependent characteristics of the same device, FIG. 5 is a characteristic diagram of hydraulic pressure as drive current and actuator pressure, and FIG. 6 is a circuit diagram of control means of a conventional device. Is. 1 ... Actuator, 2 ... Solenoid valve, 4 ... Control means, 38 ... Drive circuit, 39 ... Correction circuit, 41 ... Target vehicle height setting circuit, 43 ... Turning detection means, 46 ... Vehicle High sensor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kunio Nakagawa 5-3-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Takao Morita 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Automobile Industry Co., Ltd. (72) Inventor Mitsuhiko Hara 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corp. (72) Inventor Kenichi Kamei 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (56) References JP-A-2-41912 (JP, A) JP-A-62-96119 (JP, A) JP-A-63-106133 (JP, A) JP-A-62-15169 (JP, A) A) JP-A-63-173709 (JP, A)

Claims (1)

[Claims] Claim: What is claimed is: 1. A solenoid valve controls the suction and discharge amount of working fluid to and from a vehicle height adjusting actuator provided on each wheel, and the control means of the solenoid valve controls a specified target vehicle height signal and the vehicle height sensor. A vehicle height adjusting suspension controller for detecting a deviation from the actual vehicle height signal from the vehicle and outputting a control signal corresponding to the deviation to the solenoid valve to provide the vehicle with a vehicle height adjusting suspension. A turning state detecting means for detecting a turning state of the vehicle, and deriving a deviation from a target vehicle height and a change speed of each vehicle height adjusting actuator caused by the roll of the vehicle based on a detection signal of the vehicle height sensor. A deviation correction value set according to the deviation and a change speed set according to the change speed when the turning state detecting means detects that the turning operation is performed at a predetermined steering angle or more. Control device for the vehicle height adjustment type suspension, wherein the correction value to have a suppressing correction value detection circuit a role in addition to the control signal.