JPH02262414A - Vehicle suspension device - Google Patents

Abstract

PURPOSE:To conduct a pertinent measure according to the content of a failure by enabling selection between one failure-measure wherein active suspension is stopped to be changed to passive suspension with electric power being supplied and the other failure-measure wherein the electric power supply is cut off, in the case of the active suspension. CONSTITUTION:In a ground clearance control wherein work fluid charged to and discharged from each upper liquid chamber 5 sectioned by each piston 4 of cylinder devices 1FR-1RL provided at every individual wheel is controlled by respective supply control valves 15FR-15RL an discharge control valves 19FR-19RL, a first and a second failure detecting means for detecting the failure the first and the second failure mode among failures in which posture control can not normally conducted are provided at a control unit to control each valve 5FR-15RL, 19FR-19RL. At the time of detecting the first failure mode, the posture control is stopped, while power supply is continued to the control unit, but at the time of detecting the second failure mode, power supply for the posture control is to be shut off.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application! IF) The present invention relates to a suspension device for a vehicle.

(Prior art) Vehicle suspensions, generally called passive suspensions, are composed of hydraulic shock absorbers and springs (generally known as passive suspensions).
The suspension characteristics are set according to preset damping characteristics. Of course, it is also possible to make the damping force of the hydraulic shock absorber variable, but this results in suspension/<.

The application characteristics will not change significantly.

On the other hand, in @Kinka, a system has been proposed that allows the suspension characteristics to be changed from good to bad, as shown in the Active Suspension 3 and 11 yen. Basically, this active suspension has the following characteristics: A cylinder device is installed between the unsprung weight and the unsprung weight, and the suspension characteristics are controlled by controlling the supply and discharge of hydraulic fluid to the cylinder device (Japanese Patent Publication No. 59-1436
(See Publication No. 5).

In this active suspension, by supplying and discharging hydraulic fluid from the outside, suspension characteristics can be significantly changed for various controls such as vehicle height control, roll control, and pitch control.

In the above-mentioned active suspension, a vehicle height sensor is basically used to detect the vehicle height in order to change the posture, but if this vehicle height sensor fails, problems will occur in suspension control.

For this reason, as shown in Japanese Patent Application Laid-Open No. 62-289417, a system has been proposed that determines whether the vehicle height sensor is normal or abnormal by looking at the rate of change of the output value of the vehicle height sensor. Furthermore, as shown in Japanese Patent Application Laid-Open No. 61-282110, when the output values of some vehicle height sensors do not change even though the output values of a plurality of vehicle height sensors are changing,
A system has also been proposed in which it is determined that some of the vehicle height sensors are malfunctioning.

(Problems to be Solved by the Invention) However, in vehicles equipped with the above-mentioned active suspension, how to deal with failures that prevent attitude control from being performed normally is a problem. This failure may include failure of the hydraulic fluid supply/discharge control valve, failure of sensors used for control, or failure of the CPU, which is the core of the control unit.
There are various possible causes such as failure. Therefore, simply performing uniform failure handling, that is, fail-safe, does not necessarily provide sufficient failure handling.

Accordingly, one object of the present invention is to provide a suspension control device for a vehicle that is capable of responding appropriately depending on the nature of the failure when a failure occurs in which the attitude control of the vehicle is not performed normally.

(Structure of the Invention) In order to achieve the above-mentioned object, the present invention has the following structure. That is, as shown in a block diagram in FIG. 10, a cylinder device is installed between unsprung weights and unsprung weights and changes the vehicle height in accordance with supply and discharge of hydraulic fluid; and the cylinder device. Attitude control sum means for controlling the attitude of the vehicle by controlling the supply of hydraulic fluid to the vehicle; and a first failure detection unit for detecting a failure in a first failure mode among failures in which the attitude control is not performed normally. and second failure detection means for detecting a failure different from the first failure mode.

a first failure response control means for stopping attitude control by the attitude control means while continuing power supply to the attitude control means when a failure in the first failure mode is detected by the first failure detection means; The apparatus further includes a second failure handling control means for cutting off a power source for the attitude control when a failure in the second failure mode is detected by the second failure detection means.

(Operations and Effects of the Invention) As described above, in the present invention, while supplying power for attitude control, the active suspension is stopped and a passive suspension is used as a failure response, and the power is supplied for attitude control. By responding to a failure by cutting off the power supply, appropriate measures can be taken depending on the nature of the failure.

In particular, when only active control is canceled while power is being supplied for attitude control, it is possible to take measures when a failure is recovered and to detect other failures thereafter, as necessary.

On the other hand, if the power supply is cut off, although the above-mentioned failure recovery cannot be taken, it is possible to reliably prevent undesirable active control from being performed.

(Example) Examples of the present invention will be described below based on the attached drawings. In addition, in the following explanation, the symbol ji-r used with numbers
J is for the front wheel, r RJ is for the rear wheel, rFRJ is for the right front wheel, r F 1. , J is for left 1111 wheels, "R"
RJ means for the right rear wheel, and rRLJ means for the left rear wheel. Therefore, when there is no need to particularly distinguish between them, the explanation will be made without using these different symbols.

In the salt 3p vomit Figure 1, 1 (IFR, IFL, i RF (
, I RL ) are cylinder devices installed in each of the front, rear, left, and right directions, and these include a cylinder 2 connected to an unsprung force, and a cylinder extending from inside the cylinder 2 connected to a spring force. It has a piston rod 3. cylinder 2
Inside, a liquid chamber 5 is defined above by a piston 4 integrated with a piston rod 3, but this liquid chamber 5 and a lower chamber are communicated with each other. As a result, when the hydraulic fluid is supplied to the liquid chamber 5, the piston rod 3 extends and the vehicle height increases, and when the hydraulic fluid is discharged from the liquid chamber 5, the vehicle height decreases.

For the liquid chamber 5 of each cylinder device 1, a gas spring 6 (
6F R, 6F! 4.6 RI'l, 6 f se1. )
is connected. Each of the gas springs 6 is constituted by four cylindrical springs 7 having a small diameter, and the cylindrical springs 7 are connected to the liquid chamber 5 through an orifice 8 in a row of =1n. Of these four cylindrical springs 7, except for one, the remaining three are connected to the liquid chamber 5 via a switching valve 9. As a result, when the switching valve 9 is in the switching position as shown, the four cylindrical springs 7 are communicated only through the orifice 8, and the damping force at this time is small. Furthermore, when the switching valve 9 is switched from the illustrated position, the three cylindrical springs 7 are also communicated with the liquid chamber 5 through the orifice lO built into the switching valve 9, causing a damping force. becomes large. Of course, by changing the switching position Φ of the switching valve 9, the spring characteristics of the gas spring (3) are also changed.The suspension characteristics can also be changed by changing the supply 711 of hydraulic fluid to the cylinder device + O4 chamber 5. ] will also be changed.

In the figure, reference numeral 11 denotes a pump driven by an engine, and high-pressure hydraulic fluid pumped up by the pump 11 from a reservoir tank 12 is discharged into a common passage 13.

The common passage 13 includes a front passage 14F and a rear passage 14I (
The front passage 14N is further divided into a right front passage 14FR and a left front passage 14F[-4. This right front passage 14FR is connected to the cylinder device 1 for the right 1111 wheel. It is connected to the liquid chamber 5 of the FR, and the left front passage 14 FN- is connected to the left front passage 14 FN-, and the cylinder device IF for the left 111 wheel.
It is connected to the liquid chamber 5 of L. This right front passage 14,
From the upstream side, FR has a supply flow system #
1.5 F Pilot valve 16 F as R1 delay valve
ll is connected. Similarly, from the upstream side of the left front passage 14FL, supply flow meter control valves 15F +,...
, , a pilot valve 16FL is connected.

In the right 11Ti side passage 14FR, both valves 1.5 FR and 161:1 (a first relief passage 17 FR for the right iii side passage are connected from where between, and this first relief passage 17
Fl (finally connects to the J server tank 12 via the front/width relief passage 181'.
Relief passage! 71^l( is connected to 13 to Degawa flow: It control i wholesale valve 19 F It. Also, bar (
+-:X1~Valve l f3 F R flow passage 14 F
n is connected to the first relief passage 17FF< via the second relief passage 20FR, and a relief valve 211/river is connected to this.Furthermore, the passage 14FR closest to the cylinder device IFR filter 29F
R is interposed and there is one ζ. This filter 29 F R
is located between the cylinder device IFI and the valves 16FR and 21R located closest to the cylinder device IFI.
This prevents the wear particles generated from sliding of the valve 161 [(, 2l FR) from flowing to the R side.

Note that the passage configuration for the left 111N wheel is also configured in the same manner as the right front export passage configuration, so a redundant explanation thereof will be omitted.

The main accumulator 2 is in the ljn common passage 1:3.
2 is connected, and 1) i1 wheel relief passage 18 [?
Accumulator 2:3F is also connected to it. This main accumulator 22 is a pressure source for the yffj liquid together with the later-described subaccumulator 24, and is used to prevent a shortage in the amount of hydraulic fluid supplied to the cylinder device 1. Further, the accumulator 23F is provided to prevent the high-pressure hydraulic fluid in the front wheel cylinder device 1 from being suddenly discharged to the low-pressure reservoir tank 12, that is, to prevent the water hammer phenomenon.

The hydraulic fluid supply/discharge passage for the rear wheel cylinder device IRR1IRL is also configured in the same manner as for the front wheels, so a redundant explanation thereof will be omitted. However, in the rear wheel passage,
There is no equivalent to the pilot valve 21FR121FL, and there is no main accumulator 2 in the rear wheel passage 14R.
A sub-accumulator 24 is provided in consideration of the fact that the passage length from the front wheel is longer than that for the front wheel.

The common passage 13, that is, each passage 14F for the front and rear wheels,
14R is connected to the front wheel relief passage 18F via the relief passage 25, and the relief passage 25 includes N.
An Ill f, It valve 26 consisting of a value on/off valve is connected.

In FIG. 1, 27 is a filter, and 28 is a pressure regulating valve for adjusting the discharge pressure from the pump 11 to be within a predetermined range.
is configured as a variable displacement swash plate piston type and is integrated into the pump 11 (discharge pressure 12
0-160kg/cm2).

The pilot valve 16 is opened and closed depending on the pressure difference between the pressure in the front and rear passages 14F or 14R1, that is, the common passage 13, and the pressure on the cylinder device I side. Therefore, for the pilot valves 16FR, 1, and 6FL for the front wheels,
A common pilot passage 31F branched from the passage 14F is led out, and of the two branched pilot passages branched from the common pilot passage 31F, one passage 31FR is connected to the pilot valve 16FH, and the other passage 31F is connected to the pilot valve 16FH.
L is connected to the pilot valve 16FL.

An orifice 32F is provided in the common pilot passage 31F. Note that the pilot passage for the rear wheels is similarly configured.

Each of the pilot valves 16 is configured as shown in FIG. 2, for example, and the one shown is for the right front wheel. This pilot valve 16 has, in its casing 33,
A main channel 34 forming a part of the passage 14FR is formed,
A passage 14FR is connected to the main passage 34. A valve seat 35 is formed in the middle of the main flow path 34, and the opening/closing piston 36, which is slidably inserted into the casing 33, is seated on and off the valve seat 35, so that the pilot valve 1
6FR is opened and closed.

The opening/closing piston 36 is integrated with a control piston 38 via a valve shaft 37.
is slidably inserted into the casing 33 to define a liquid chamber 39 within the casing 33, and the liquid chamber 39 is
It is connected to the branch pilot passage 31FR via the control flow path 40.

The control piston 36 is then operated by a return spring 41.
, the direction in which the opening/closing piston 36 is seated on the valve seat 35,
That is, the pilot valve 16FR is biased in the closing direction. Furthermore, the pressure of the main flow path 34 is applied to the control piston 38 via the communication port 42 on the side opposite to the liquid chamber 39 . As a result, inside the liquid chamber 39 (common passage 1
3 side) becomes 1/4 or less of the pressure in the main flow path 34 (cylinder device IFR side), the opening/closing piston 36 seats on the valve seat 35 and the pilot valve 16FR is closed.

Here, from the state where the pilot valve 16FR is open,
Common passage 13 (When the pressure of 11+1 decreases significantly,
Due to the action of the orifice 32F, this pressure drop is delayed and transmitted to the liquid chamber 39, so that the pilot valve 1 in question is
6FR is closed after a delay from the pressure drop (in the embodiment, this delay time is set to about 1 second).

Next, the effect of the above-mentioned answer will be explained.

■Switching valve 9 In the embodiment, the switching valve 9 is operated to increase the damping force only during turning.

■Relief valve 21 The relief valve 21 is normally closed and the cylinder device l
The pressure on the side is less than a predetermined value (160 to 200 k
g/cm2), it opens.

In other words, it serves as a safety valve that prevents the pressure on the cylinder device 1 side from becoming abnormal.

Of course, the relief valve 21 is a cylinder device iRn for the rear wheel.
, l R1, , , can also be provided, but in the embodiment, it is assumed that the vehicle has a considerably larger weight distribution on the front side than on the rear side, and the weight distribution on the rear wheel side The relief valve 21 is not provided on the rear wheel side in consideration of the fact that the pressure on the front wheel side does not become greater than the pressure on the front wheel side.

(2) Current control valve 15.19 Both the supply and discharge flow rate control valves 15.19 are electromagnetic spool valves that can be switched between an open state and a closed state as appropriate. However, when it is open, it has a differential pressure adjustment function that keeps the differential pressure between the upstream and downstream sides almost constant (due to flow rate control, this differential pressure must be kept constant). ). More specifically, the displacement position or opening degree of the spool of the flow control valve 15.19 is changed in proportion to the supplied current, and this supplied current is determined based on a flow rate-current correspondence map created and stored in advance. Determined based on That is, the supplied current corresponds to the required flow rate at that time.

By controlling the flow rate control valves 15 and 19, the supply and discharge of hydraulic fluid to the cylinder device 1 are controlled, thereby controlling the suspension characteristics.

In addition to this, when the ignition is OFF, this O
For a predetermined period of time (2 minutes in the embodiment) from the time of FF, only the control in the direction of lowering the vehicle height is performed. In other words, it takes into account changes in the payload caused by getting off the vehicle, etc., and prevents the vehicle height from becoming partially high (maintaining the standard vehicle height).
.

■Control Valve 26 The control valve 26 is normally closed by being energized, and is opened in the event of a failure. This failure can occur, for example, if part of the flow control valve 15 or 19 becomes stuck, if the sensors described below fail, if the hydraulic pressure of the hydraulic fluid fails, or if the pump 11 fails. There are cases etc.

In addition, in the embodiment, the control outlet valve 26 is opened after a predetermined period of time (for example, 2 minutes) has elapsed since the ignition was turned off.

Note that when this control valve 26 opens, the pilot valve 1
6 is closed with a delay, as described in ii.

■Pilot valve 16 As already mentioned, the orifices 32F and 32R open the pilot valve with a delay after the pressure in the common passage 13 has decreased. This means that, for example, in the event of a failure in which a part of the flow rate control valve 15 remains open, the passages 14FR to 14
RI- is closed and the cylinder device 1. The hydraulic fluid in FR to IRL is confined and a small height is maintained. Of course, at this time, the suspension characteristics are fixed to so-called passive characteristics.

FIG. 3 shows the control system of the hydraulic fluid circuit shown in FIG. 1. In this Figure 3, WFR is the right front wheel, W
F L is the left front wheel, WRR is the right rear wheel, WRL is the left rear wheel, and [J is a control unit configured using a microcomputer. This control unit (J includes each sensor 51FR to 51R [4, 52FR to 52
R1, -, 53F R, 53F L.

53■(, 61 to 64) are manually input, and in addition to this, the ignition switch 71 is turned on and the 017F signal is input. (15FR~1.5RL)
, l 9 (19FR~], 9 R1, -) is outputted to the control valve 26 and the alarm device 72 such as a seventh alarm lamp and a buzzer.

The distribution sensors 51FR to 51RL are connected to each cylinder device 1.
．． It is provided at F R to R1- to detect the amount of extension, that is, the vehicle height at each wheel position. sensor 5
2FR~5・2RL are each cylinder equipment i! IFR-I
It detects the pressure in the liquid chamber 5 of the RL (see also FIG. 1). The sensors 53FR153FL and 53R are G sensors that detect acceleration in the vertical direction. However, vehicle B
On the front side of the
A sensor 53FR153FL is provided, but at the rear of the vehicle, only one G sensor 53R is provided at a left-right intermediate position on the rear axle. In this way, one virtual plane representing the vehicle body B is defined by the three G sensors, and this virtual plane is set to be a substantially horizontal plane. The above sensor 61
is for detecting vehicle speed. The sensor 62 detects the operating speed of the steering wheel, that is, the steering angle speed (
In reality, the steering angle is detected and the steering angle speed is calculated from the detected steering angle.) The sensor 63 is
It detects the lateral G acting on the vehicle body (in the embodiment, only one is provided on the Z axis of the vehicle body).

The control unit U basically performs active control conceptually shown in FIG. 4, that is, in the embodiment, vehicle attitude control (vehicle height signal side @), ride comfort control (vertical acceleration signal control), Vehicle torsion control (pressure signal side fit) is performed. The results of each of these controls are finally expressed as the flow rate of the hydraulic fluid flowing through the flow rate control valve 15, 19 serving as the flow rate adjusting means.

Next, an example of how to control the suspension characteristics based on the output of each sensor will be explained with reference to FIGS. 4 and 5.

The content of this control can be roughly divided into the most basic attitude control of the vehicle body B based on the output of the vehicle height sensor, the ride comfort control section based on the output of the G sensor, and the torsion suppression of the vehicle body B based on the output of the pressure sensor. It consists of control and is divided into the following parts.

■Attitude control (vehicle height sensor signal control) This control consists of three attitude controls that suppress bounce, pitch, and roll.
Feedback control is performed using PD control fIl (proportional-derivative control).

For each of these three attitude controls, how to handle the output from each vehicle height sensor is indicated by the "+" and "-" signs shown on the left side of the figure for each control section for bounce, pitch, and roll. This is shown by Furthermore, the "+" and "-" signs shown on the right side of each control section in the figure indicate that each control section controls posture changes. The sign opposite to the one shown on the left side of the center is written.

In other words, in bounce control, the added value of each vehicle height on the left and right front sides and the added value of each vehicle height on the left and right rear sides are P D III fil in the direction that matches the reference vehicle height value, and the control formula used when bounce is applied. is shown in the following equation [1].

Kal+ (T82・S/(1+TB2・S)1 ・
Kf12・・ (1) KBI, KH2, TB2: Control gain (constant) S: Operator In addition, in pitch control, the added value of the vehicle height on the left and right rear sides is added to the added value of each vehicle height on the left and right front sides. P D III gIJ is performed in the direction in which the subtracted value becomes zero. Further, in the roll control, the PD control is performed in a direction in which the added value of each vehicle height on the left front and rear sides matches the added value of each vehicle height on the right front and rear sides (so that the target roll angle is achieved).

Each control value obtained by the three PD controls described above is obtained for each of the four cylinder devices 1, and is added to each other for each control value for each cylinder device 1. Finally, the control values for the four attitude control The current I signal is determined as QXFR-QXIIL.

Of course, for both the pitch control and the roll control, the control equation for the PD control is in the form of equation (1) above (however, the control section gain is set for the pitch control section and for the roll control. ).

(2) G ride comfort control (G sensor signal control B) This ride comfort control is intended to prevent the deterioration of ride comfort caused by the posture 1u control in (2) above. Therefore, in response to the three posture controls mentioned in (■) above, each of bounce, pitch, and roll is controlled so as to suppress the vertical acceleration.
Feedback control is performed using the IPD system @ (integral-proportional one-integral system fil), and the control equation based on this IPD control is shown in the following equation (2).

(Tf33/ (1+TB3・S)) ・K B3+
K B4+(T 113・S/(x+TB3・S)
1 ・KB3・ ・ ・ (2) K, B3. 1 mouth 3: Control gain (constant) S: Operator However, in equation (2), each control gain is
Dedicated systems are used for bounce system (1), pitch system (1), and roll control.

Since there are only three G-sensors for ride comfort control, the arithmetic mean of the front left and right downward accelerations is used as the front vertical acceleration for pitch control. In addition, during roll control, only the left and right vertical accelerations on the front side are used, and the vertical accelerations on the rear side are not used.

In this ride comfort control as well, each control B value obtained by the three IPD controls described above is obtained for each of the four cylinder devices 1, and is added to each other for each control value for each cylinder 1 to obtain the final value. are determined as four flow rate signals QGFR-QGRL for ride quality control.

■Warb control (controls pressure signal ia+) Warb control is for controlling the torsion of the vehicle body B. That is, since the pressure acting on each cylinder device 1 corresponds to the load on each wheel, control is performed so that the torsion of the vehicle body B due to this load does not become large.

Specifically, feedback control is performed in a direction such that the ratio of the difference and the sum of left and right pressures is 1 for each of the front side and rear side of the vehicle body. The weighting is such that the amount of torsion on the front side and the rear side of the vehicle body is weighted by the coefficient ωF, and the weighting is applied to each of the controls (1) and (2) by the coefficient ωA. Of course, also in this twist suppression control, the control value is finally determined as the flow rate signal QPFR-QPRL (%) for each of the four cylinder devices 1.

The flow rate signals for attitude control, ride comfort control, and torsion suppression control determined for each of the four cylinder devices as described above are finally added to form a final flow rate signal QF.
It is determined as R-QRL.

(Left below) ①-L The control gain of the control formula used in the explanation of FIG. 4 is controlled on the switching side by a control system as shown in FIG.

First, a value S obtained by multiplying the steering angular velocity θ- by the vehicle speed V and calculating a reference value G from the resultant θ-cross is input to the turning determination section. Also, the current lateral acceleration G of the vehicle
The value S2 obtained by subtracting the reference value G2 from s is set at the turning 'I'll constant section. Then, at the turning Ill/running section, human power S
1 or S! If ≧0.

It is determined that the vehicle is turning, and the suspension characteristic hardening signal Sa is output, and the damping force switching valve 10 is switched to the throttle position in order to improve the followability of flow control for each hydraulic cylinder 3. Each proportionality constant Ki (i=
B+-84) are each set to the large value Kl-tard, and each target roll TROLL is stored in advance.
It is set to a value corresponding to the lateral acceleration Gs at that time. An example of this map.

This is shown in FIG. Incidentally, in the case of a passive suspension vehicle, as shown in FIG. 7, the roll angle (positive roll) becomes thicker as the lateral 6 increases.

On the other hand, when the input SI and the curvature are 0 in the turning determination section, it is determined that the vehicle is traveling straight, and the suspension characteristic softening signal sb
is output, the damping force switching valve 10 is switched to the same position, the proportionality constant Ki is set to the normal value Kso f t, and the target roll angle T ROLL is set to 0.

Next, we will explain the failure detection and response of equipment used for active system (wholesale).

The details of the control unit U are shown in FIG. 9 in more detail, which will be described later.

First, as responses when a failure is detected, that is, responses in the event of a fail, in the embodiment, there are fail mode A, fail mode B, fail mode C, and fail mode D.
There are four types.

Fail mode C: Fail mode A is performed by immediately stopping active control at the time of failure detection, opening the relief circle side (oil well 26, and activating the alarm 72).

Fail mode C: In fail mode B, when a fail is detected, the discharge control valve 19 is fully opened for 1 second to discharge the working fluid from each cylinder device 1 at maximum current for 1 second)
, After this, the relief circle side Mii 26 was opened, and the 7th alarm device 7 was opened.
Activate 2.

Fail mode C: Fail mode C corresponds to a minor failure and simply activates the 9 alarm device 72.

Fail mode C: Fail mode D is 1lill
This is in response to a failure of the wholesale unit U, especially a failure of the CPU, and the power supply to it is cut off.

Among the above fail modes A-D, fail mode C
For -1, turn off the ignition switch 71.
When ONL again after F L, active control is started again (with active control return). In the case of fail modes B and D, even if the ignition switch 71 is turned OFFFL and then turned ON again, there is no possibility of returning to active control. Furthermore, in the case of fail mode A, depending on the failure details, when the ignition switch 71 is turned off and then turned on again, active control is permitted (there is a possibility of active control returning); There are two types: when rB is prohibited (no possibility of recovery), and in the explanation of the failure details below, when it is ``1'', there is a possibility of recovery, and when it is ``O'', there is no possibility of recovery. The case is shown below.

In other words, in the following explanation, for example, when the fail mode is indicated as A-1, it means that the fail mode is A and there is a possibility of recovery for active control, and when it is indicated as A-0, the same fail mode is A-1. This indicates a case where there is no possibility of returning to active control.

Next, the relationship between the details of the failure and the corresponding fail mode will be explained below.

Immediately after the ignition switch is turned on, all switching valves 9 are set to the hard switching position, but if all switching valves 9 are not at the hard switching position even after 2 seconds have passed since the ignition switch 71 was turned on, It is determined that the switching valve 9 is in failure, and each switching valve 9 is reset to the soft switching position (fail mode A).
-11゜Turn the ignition switch 71 ONL and then 5
When the pressure in the main accumulator 22 detected by the sensor 64 does not exceed 30 kgf/cm2 even after seconds have passed (fail mode Δ-〇).

When the ignition switch 71 is turned on and the actual vehicle height is 30 mm lower than the reference vehicle height (fail mode C).

Relief control (5 seconds after the oil well 26 is turned off, the pressure in the main accumulator 22 is 30 kgf'/c
When m2 or more (fail mode 8-0).

When the output signal of the pressure sensor 64 is 4.5■ or more (1 to
4v range is normal output value and fail mode A-0).

When the output signal of the pressure sensor 64 is 0.5V or less (fail mode A-1).

When the output signal of the pressure sensor 64 indicates 185 kgf/cm2 or more (fail mode A-0).

The output signal of pressure sensor 6...1 is lOOkgC/c
When the output signal of the pressure sensor 64 does not indicate an increase in the pressure F for 5 seconds or more when the active control piece is in a state of 1 or less (Fail mode A-0).

1 inch "The time from unloading cut 1 to cut in by valve 28 is less than 1 second, and 2' in 17 for 5 consecutive seconds.
- In the case of ↑2 (fail mode A-1).

The change in the output signal from the pressure sensor 64 in 1 second is 2 k, g t' / Cm2pJF.
J sound ()J~ (Lemode AO) that lasted for more than 1.0 minutes
.

Even though the control 1F valve 26 is in the cut-in state, the amount of change in the output signal from the pressure sensor T34 per second is 2.
If +ζf/cm2 or more continues for 5 seconds Y' ()

When the output signal of 3 or 63 detects 0, 1 ('; or 5), the output signal of 5 pressure sensor 64 changes in 1 second. 2 kg f' / e m 2 or more I: If no change continues for 5 seconds (] L mode A -
1).

After it has been detected that the bump j1t of the wheel 1j has become:, 30 mm or more -F, the change in the output No. 11 from the pressure sensor 64;
2 or more, 1- If no change continues for 5 seconds LaU-+- (fail mode Δ-1).

11: J sound in which the pressure of 90klZ['/cm2 or less was detected by the Kasenza 64 (fail mode l to -1).

8 When a sensor or actuator is disconnected (fail mode A-0).

J+r- When it is detected every second that the working flow 21 in the tank 12 has become constant T' (fail mode A-0).

8 When the output signal of the cylinder pressure sensor 52 is 0.5 VV or more than 4.5 V (-) (1 to 4 is the normal output/range of 11 degrees, fail-mo 1 core to -0).

Hlj export is rebound [! When there is a further rebound from ζ, the cylinder L1-sen→) 52 continues to output the pressure (failure) for 300 rnsec or more (fail mode 13-0).

When the lj wheel bumps from the bump state to the river, the cylinder pressure sensor 52 indicates that the pressure drop is 300 m.
If the output is continued for more than sec (fail mode B -01° small wheel is: 30 mm Vi J-bumped,
When the cylinder Y sensor 52 continuously outputs the output J-ζ of 30 kgt'/am2 or more for 300 m5ec or more (fail mode [3-0).

When the cylinder pressure sensor 52 continuously outputs an output signal of 100 kgf'/cm,' or more for 300 m5ec or more with the middle wheel rebounding upward by 60 mm V) (fail mode B-0).

When the output signal of the cylinder pressure sensor 52 does not change from the pressure of the above-mentioned small height change 1iii of 30tr+m or more within 0, ;3 seconds after the vehicle height of a certain heavy wheel changes by more than Om m. (Fail mode 7\-1).

The output signal of the small height sensor 51 is 0.5V or more 1ζ or 1
, 53 ■ 1. When (1~4■ is the normal output range)
”-Ilmode 8-0).

The output signal of the small height sensor of a certain middle wheel does not change for 3 seconds after j changes by O, I (Noir 7-Dono-1).

When the output signal of the G sensor 53.63 is continuously above 0.5V or 4.5L for more than 1 hour (1 to 4
is the normal output range of 1F, )L mode/~-〇).

2 + [41 or 3 1-de (output of 5 sensor 53 is different from output of 100 msec +1ii -)
However, the output of the sensor on the other upper F is 100 m s
e c t'l: When the state that the output of l does not change continues for 500 mse, c (fail mode A-1).

11 High sensor 5 (output value of - degree for 10 minutes [1
When it is not in the vicinity of il'I (range of ±2 m, m) (-) L-il 1,000/~-1).

When the state in which all the switching valves 9 are not in the same OFF position continues for more than 1 second (Hue, Ilmoto A-1).

When each switching valve 9 reaches the same switching position but does not reach the commanded switching position within 10 seconds (fail mode A-1).

The output of the lateral G sensor 63 is 0.5V or less or = 4.5
When it is more than V (1 to 4 is the normal output range, fail mode A-0).

When the output of the steering angle sensor 62 is 0.5V or less or 4.5V or more (1 to 4V is the normal output range, fail mode A-0).

CPU error (fail mode A-0).

Failure of the CPU, etc. in the control unit U (Fail mode D).

Details of Unit U 9 Here, the specific configuration of the control unit U will be described with reference to FIG. 9.

First, the control unit U has a master CPTJ 101,
Three CPUs, a sub CPU 102 and a DSP (digital signal processor) CPU 103, are provided, and a power IC circuit 104 and a power cutoff circuit 105 are also provided for power supply control.

Among the three CPUs mentioned above, for the sub CPU 102,
Power is constantly supplied from the battery.

On the other hand, for the master CPUl0I and DSPIO3, power from the battery is supplied to the circuits 105 and 1.
04 and then supplied. And the power cutoff circuit 10
5 supplies and cuts off power according to the on/off state of the ignition switch 71, and also controls the CPU l0I.
, 102 , the power supply is also cut off based on a cutoff command signal from the DSP 103 .

The master CPU 101 receives human power from each of the sensors described above, and outputs power to each actuator such as a control valve. In addition, the sub CPTJ102 has no input/output relationship with the above sensors and actuators, and is connected to the master CPU.
Checks for abnormalities by mutual monitoring with 10I, and stores the above-mentioned failures in the backup memory when they occur. Note that the stored failure information is read out as a failure code signal at a maintenance shop or the like as appropriate. Furthermore, like the sub-CPU 102, the DSP 103 has no input/output relationship with each sensor or actuator, and mainly performs mutual monitoring to check for abnormalities in the calculation relationship with the master CPU.

Mutual monitoring between CPU10I and 102, CPU10
As a result of mutual monitoring between the I and the DSP 103, if it is determined that there is an abnormality in either the CPU or the DSP, a command signal for power cutoff is output to the power cutoff circuit 105. As a result, power supply to the CPU 101 and DSP 103 is cut off (fail mode D).

Flowchart 8 FIG. 8 is a flowchart showing what to do when a failure occurs, and this flowchart will be explained below. Note that in the following explanation, S indicates a step.

First, in Sl, it is determined whether the flag F is 1 or not, and this flag is set to 1 when a failure is detected.If the determination in Sl is No, a failure signal, that is, as described above, is sent in S2. Based on the failure check (results are input). Then, in S3, it is determined whether or not a failure has occurred based on the manual result in S2.

If the determination in S3 is No, no failure has occurred, and the process returns as is. Also, S3? If YES in step 11, the failure mode (failure content corresponding to the above-mentioned fail modes A to D) is identified in S4. After this, processing corresponding to each fail mode A to D is performed. That is, when it is determined in S21 that the failure corresponds to fail mode D, S22
At this point, the power to the CPU 10I and the DSP 102 is cut off, and the process ends. Further, when it is determined in S8 that the failure corresponds to fail mode A-0, the above-described fail mode A control is performed in S9, and then flag F is set to 1 in SIO and the process returns. When the SLL determines that the failure corresponds to fail mode A-1, the process of S12.513 (S9, corresponding to SIO) is performed, and the determination of S14 indicates that the failure corresponds to fail mode C. When it is determined that there is, S15.516 (
S9, corresponding to SIO) is performed.

If t11 of SI4 is No, fail mode A,
Since it is possible that an unexpected failure that is not one of -1) has occurred, active control will be temporarily suspended.

r+iN Note S10. After the processing in 513 or S16 is completed, 5lOell will be answered as YES. At this time, S
At step 18, it is determined whether the failure corresponds to fail mode B or 80 or 100. With this SI8 determination, N
When O, the ignition switch 7 is turned off in S19.
When 1 is turned off, 100 yen is charged. In this determination in S19, Y I:.

When S, flag F is reset to O. Also, S
18 ↑ Ribetsu Y! When E S and r1 of S19
If the answer to question 1 is No, the process returns directly without going through S20. In this way, after S20, there is a possibility that the acceleration control will be performed when the ignition switch 71 is turned on again.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention, and shows a hydraulic fluid circuit. FIG. 2 is a sectional view showing an example of the pilot valve in FIG. 1. FIG. 3 shows a control system of the circuit shown in FIG. 1. FIGS. 4 and 5 are overall system diagrams showing an example of active control. FIG. 6 is a diagram illustrating an example of roll characteristics in the Ac-Deep suspension. FIG. 7 is a diagram showing an example of roll characteristics in the passive suspension width. FIG. 8 shows the flowchart of the present invention (without being pushed down). FIG. 9 is a diagram showing the configuration of the control unit in more detail.
:'R-15R1,= :Supply control valve 19 F R~
1.9 RL,: Extraction side i oil well U: system (wholesale unit 101: master cpu 102: sub CP tJ 103: digital signal processor 105: power cutoff circuit patent applicant Nardec Co., Ltd. Mazda Corporation I16 ( 16″゛. Three

Claims (1)

[Claims] (1) A cylinder device installed between the sprung weight and the unsprung weight to change the vehicle height according to the supply and discharge of hydraulic fluid, and by controlling the supply and discharge of the hydraulic fluid to and from the cylinder device. , an attitude control means for controlling the attitude of a vehicle; a first failure detection means for detecting a first failure mode among the failures that prevent the attitude control from being performed normally; and a first failure detection means for detecting a failure different from the first failure mode. a second failure detection means for detecting a failure in the first failure mode; and when a failure in the first failure mode is detected by the first failure detection means, stopping the attitude control by the attitude control means while continuing power supply to the attitude control means. and a second failure response control means for cutting off the power supply for the attitude control when a failure in the second failure mode is detected by the second failure detection means. A vehicle suspension device characterized by: