JPH08156561A - Suspension control device - Google Patents

Abstract

PURPOSE: To relieve a sense of incompatibility of an occupant through an improvement in control characteristics by arranging a means which supplies/ discharges fluid to/from an actuator interposed between an upper member and a lower member of a spring of a vehicle and controls damping force according to a traveling condition and corrects its control quantity according to the magnitude of the damping force. CONSTITUTION: Target damping force or actual condition damping force CT of an actuator 36 by final target damping force control is increased, and when responsiveness and generating force of the actuator 36 are enhanced, control target pressure Puj of a pressure control valve 22 is reduced through reductive correction of an active control gain. Therefore, excessive control to the actuator 36 is relieved. On the other hand, when these are reduced, the control target pressure Puj of the pressure control valve 22 is increased through increasing correction of the active control gain. Therefore, oil supply to the actuator 36 through the pressure control valve 22 is promoted, and a control delay caused when the responsiveness and the generating force of the actuator 36 are reduced is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension control for increasing / decreasing a supporting load of an unsprung member by supplying / discharging a working fluid by an actuator interposed between an unsprung member and an unsprung member of a vehicle. Regarding the device.

[0002]

2. Description of the Related Art A vehicle changes its behavior by a road surface input through an unsprung member, a driver's steering wheel operation, accelerator operation, brake operation, or the like. Specifically, the vehicle height changes, and bouncing, roll, pitch, etc. occur on the vehicle body. Such vehicle behavior gives an occupant an uncomfortable feeling, and adversely affects the steering stability and riding comfort of the vehicle. Therefore, various techniques for controlling the behavior of the vehicle body have been conventionally proposed. One of them is a so-called active suspension in which the supporting load of each wheel is positively increased or decreased by an actuator.

In recent years, various improvements have been added to this active suspension. For example, Japanese Patent Laid-Open No. 3-258605 proposes a technique in which a gas spring utilizing the elasticity of gas is connected to a cylinder with a variable throttle interposed, and the damping force generated in this cylinder is controlled to be changed. In the active suspension proposed in Japanese Patent Application Laid-Open No. 3-258605, when a transient swing occurs, the throttle opening of the variable throttle is reduced to improve the control response of the actuator and suppress a rapid posture change. Is being pursued.

In this way, the response changes depending on the throttle opening, in the working fluid system formed by the cylinder and the gas spring, the movement of the working fluid between the gas spring and the variable throttle depending on the throttle opening. Is limited. Further, due to the limitation of the movement of the working fluid, the damping force generated by the cylinder is determined, and the damping force increases as the throttle opening becomes smaller.

[0005]

In the suspension control device proposed in the above publication, the control amount of the solenoid for adjusting the diaphragm opening of the variable diaphragm is controlled by the degree of change speed of the longitudinal and lateral acceleration of the vehicle. Was calculated accordingly. On the other hand, the control amount of the actuator, that is, the control amount of active control that generates a force for positively increasing or decreasing the supporting load shared by each wheel is calculated according to the degree of longitudinal and lateral acceleration of the vehicle. . Moreover, the calculation of the control amounts of both of them is performed independently. That is,
Although the responsiveness of the actuator changes according to the throttle opening of the variable throttle, the control amount of the actuator does not take into account this change in responsiveness, and thus the damping force change that is changed by the variable throttle opening. , Was calculated according to the degree of longitudinal acceleration of the vehicle. In addition, the throttle opening (solenoid control amount) of the variable throttle that changes the responsiveness and damping force of the actuator depends on the degree of change in the longitudinal acceleration of the vehicle without considering the control amount of the actuator. It was calculated. Therefore, in the suspension control device proposed in the above publication, the following problems have been newly pointed out. Hereinafter, this problem will be specifically described.

The force F (force to increase or decrease the support load of the vehicle body) obtained by supplying and discharging the working fluid to and from the actuator is the cylinder stroke x, the stroke speed dx, the spring constant exerted by the actuator K, and the damping coefficient. When is expressed as C, it can be expressed by the following equation. Then, this equation can be transformed into an equation. In the equation, S is a Laplace factor, Q is the working fluid flow rate in the actuator, and A is the cylinder pressure receiving area of the actuator.

F = K * x + C * dx ... Equation F = (K + C * S) * x = (K + C * S) * Q / A ... Equation

By the way, when the movement of the working fluid is limited by reducing the throttle opening of the variable throttle, the working fluid flow rate Q in the actuator increases to the extent that the movement of the working fluid with the gas spring is limited. Change. Therefore, from the equation, the force F generated by the actuator increases. That is, when the throttle opening of the variable throttle is reduced, not only the responsiveness and damping force of the actuator increase, but also the force F generated by the actuator increases. Therefore, if the actuator is drive-controlled with a control amount calculated according to the degree of longitudinal acceleration of the vehicle or the like, the control becomes excessive and the desired effect of suppressing the change in posture cannot be obtained, which may give an occupant an uncomfortable feeling. there were.

The working fluid (oil) is supplied to the actuator by a pump in which the rotation of the engine is transmitted through gears. This pump has a relatively small size in consideration of mountability on a vehicle, weight, and the like. In this case, an accumulator is also used in order to avoid the pulsation of oil and stabilize the supply pressure.
However, as for this accumulator, a relatively small one is also used in consideration of mountability in a vehicle.

The flow rate of oil discharged from the pump is limited not only by its capacity but also when the rotational speed of the pump is low, for example, when the engine is running at low speed. The decrease in the flow rate when the engine speed is decreased occurs regardless of the capacity. Therefore, in such a case, since the flow rate that can be supplied to the actuator decreases, the actuator may not be able to be driven with the control amount calculated according to the degree of the longitudinal acceleration of the vehicle or the like. For this reason, the control of the actuator is insufficient, so that the desired effect of suppressing the change in posture cannot be obtained, and the occupant may feel uncomfortable. Such a situation of insufficient control of the actuator can occur not only when the supply amount of oil decreases, but also when the supply pressure decreases. It should be noted that the pump capacity and the accumulator can be increased in size in order to eliminate the insufficient control of the actuator, but this is not a practical solution because it causes deterioration in mountability and an increase in weight.

Also, due to an unexpected cause, there is a possibility that the degree of adjustment of the aperture of the variable aperture may not be seen in normal running. Such a situation is, for example, a case where a step motor for driving the variable aperture is out of step and the normal drive of the variable aperture cannot be obtained.

Under these circumstances, the diaphragm opening of the variable diaphragm cannot be driven according to the control amount, so that the damping force cannot be effectively changed. In addition, the damping control for the posture change such as the longitudinal acceleration of the vehicle is insufficient. Moreover, not only this, but as described above, since the diaphragm opening of the variable throttle, the response of the actuator in the active control, and the generated force have a correlation, when the normal drive of the variable throttle cannot be obtained. The active control may adversely affect the operability or riding comfort of the vehicle.

The above-mentioned various problems will be summarized as follows.
It looks like this: That is, in the conventional suspension control device, when the damping force change control through adjustment of the throttle opening of the variable throttle and the active control through supply and discharge of working fluid to and from the actuator are used together, the throttle opening of the variable throttle is opened. We did not pay attention to the fact that the degree and the responsiveness of the actuator in the active control and the generated force are correlated with each other, and both controls were performed without any relation. Therefore, the effectiveness of both of these controls is impaired, which adversely affects the behavior control of the vehicle body.

The present invention has been made to solve the above-mentioned problems, and a suspension for performing damping control and active control through an actuator interposed between a sprung member and an unsprung member of a vehicle. The purpose of the present invention is to reduce the discomfort of the occupant by improving the control characteristics of the control device.

[0015]

In order to achieve the above object, the means adopted by the suspension control device according to claim 1 is interposed between an unsprung member and an unsprung member of a vehicle, and a means for working fluid is provided. An actuator that increases / decreases the supporting load of the corresponding unsprung member by supplying / discharging, supply / discharging means for supplying / discharging the working fluid to / from the actuator by the supply of the working fluid from the working fluid supply source, and the actuator A damping force changing means for changing the damping force, a running state detecting means for detecting a running state of the vehicle, and a spring according to the running state of the vehicle for controlling the supply / discharge means with a control amount according to the detected running state. The supply / discharge control means for performing the above behavior control via the actuator, and the control amount when the supply / discharge control means controls the supply / discharge means are controlled by the magnitude of the damping force by the damping force changing means. Depending the gist that a control amount correction means for correcting.

Further, the means adopted by the suspension control device according to claim 2 is interposed between the sprung member and the unsprung member of the vehicle, and the supporting load of the corresponding unsprung member by supplying and discharging the working fluid. An actuator for increasing / decreasing, a supply / discharge means for receiving / supplying a working fluid from a working fluid supply source, for supplying / discharging the working fluid to / from the actuator, and a damping force changing means for changing a damping force generated by the actuator, A traveling state detecting means for detecting a traveling state of the vehicle, the supply / discharge means is controlled by a control amount according to the detected traveling state, and a sprung behavior control according to the traveling state of the vehicle is achieved through the actuator. The supply / discharge control means, the working fluid supply monitoring means for monitoring the supply status of the working fluid from the working fluid supply source, and the supply decrease of the working fluid based on the monitored supply status of the working fluid. When it is conjectured, the damping force increases as the supply of the working fluid decreases, and a damping force change control unit that controls the damping force change unit according to the supply state of the working fluid is provided. And

The means adopted by the suspension control device according to the third aspect is interposed between the sprung member and the unsprung member of the vehicle, and increases / decreases the supporting load of the corresponding unsprung member by supplying / discharging the working fluid. Actuator, a supply / discharge means for receiving and supplying a working fluid from a working fluid supply source, for supplying / discharging the working fluid to / from the actuator, a damping force changing means for changing a damping force generated by the actuator, and A traveling state detecting means for detecting a traveling state, and the supply / discharge means for controlling the supply / discharge means by a control amount according to the detected traveling state so as to perform sprung mass behavior control according to the traveling state of the vehicle through the actuator. A control means, a supply / discharge suitability determination means for determining whether the supply / discharge control of the working fluid to / from the actuator is effective, and a supply / discharge suitability determination means for determining whether the supply / discharge control of the working fluid is effective or not. When the can, on the side where the damping is enhanced for sprung vibration expressed on spring according to the road surface input,
The gist is to include a damping force change control means for controlling the damping force change means according to the road surface input.

The means adopted by the suspension control device according to claim 4 is interposed between the sprung member and the unsprung member of the vehicle, and the supporting load of the corresponding unsprung member is increased or decreased by supplying and discharging the working fluid. Actuator, a supply / discharge means for receiving and supplying a working fluid from a working fluid supply source, for supplying / discharging the working fluid to / from the actuator, a damping force changing means for changing a damping force generated by the actuator, and A traveling state detecting means for detecting a traveling state, and the supply / discharge means for controlling the supply / discharge means by a control amount according to the detected traveling state so as to perform sprung mass behavior control according to the traveling state of the vehicle through the actuator. Control means, damping force change state monitoring means for monitoring the changing state of the damping force by the damping force changing means, and a reduction function for judging whether the damping force change by the damping force changing means is effective or not. When the force change adequacy determining means and the damping force change adequacy determining means determine the effective inadequacy of the damping force change, the control amount when the supply / discharge control means controls the supply / discharge means is set to the damping force change. The gist of the present invention is to include a control amount correction unit that corrects the damping force according to the changed state of the damping force monitored by the state monitoring unit.

The means adopted by the suspension control device according to claim 5 is interposed between the sprung member and the unsprung member of the vehicle, and increases or decreases the supporting load of the corresponding unsprung member by supplying and discharging the working fluid. Actuator, a supply / discharge means for receiving and supplying a working fluid from a working fluid supply source, for supplying / discharging the working fluid to / from the actuator, a damping force changing means for changing a damping force generated by the actuator, and A traveling state detecting means for detecting a traveling state; and a feeding / discharging control means for controlling the feeding / discharging means in accordance with the detected traveling state and for performing sprung mass behavior control in accordance with the traveling state of the vehicle through the actuator. , The effectiveness of the supply / discharge control and the effectiveness of the change of the damping force based on the status of the supply / discharge control of the working fluid to / from the actuator and the status of the change of the damping force by the damping force changing means. Harmony capable side, and its gist in that it comprises a conditioning means for conditioning controlling said supply and discharge control means and the damping force changing means.

[0020]

In the suspension control device having the above-mentioned structure, when the working fluid is supplied to or discharged from the working fluid supply source to the actuator through the supply / discharge means, the traveling detected by the traveling state detecting means. The supply / discharge control means controls the supply / discharge control means with a control amount according to the state. As a result, the actuator increases / decreases the support load of the unsprung member of the vehicle by receiving and supplying the working fluid according to the traveling state. Therefore, the behavior of the sprung member is controlled according to the running state of the vehicle. In addition, the behavior control on the spring here includes various controls that can be realized by an actuator that increases or decreases a supporting load, such as vehicle height maintenance control and attitude change suppression control.

On the other hand, in the suspension control device according to the first aspect, when the damping force changing means changes the damping force of the actuator, the control amount when the feeding / discharging control means controls the feeding / discharging means is damped. It is corrected by the control amount correction means according to the magnitude of the force. Therefore, when the damping force is increased and the responsiveness of the actuator is increased, the control amount of the supply / discharge means is corrected to be decreased to suppress the supply of the working fluid to the actuator, and the responsiveness of the actuator and the generated force are suppressed. The excessive control due to the increase in On the other hand, when the damping force is decreased and the responsiveness of the actuator becomes low, the control amount of the supply / discharge means is corrected to be increased to promote the supply of the working fluid to the actuator.
The control delay due to the low response of the actuator is improved. That is, the responsiveness of the actuator and the generated force are adapted to the change of the damping force through the suppression and promotion of the supply of the working fluid.

In the suspension control device according to the second aspect, the working fluid supply monitoring means monitors the supply status of the working fluid from the working fluid supply source. Then, when a decrease in the supply of the working fluid is observed from the monitoring result, the damping force changing control unit controls the damping force changing unit according to the supply state of the working fluid to reduce the damping force generated by the actuator to the damping force. Increase to increase. Therefore, even if the responsiveness of the actuator and the generated force are reduced due to the decrease in the supply of the working fluid, it is possible to secure the control amount necessary for the behavior control of the sprung member by increasing the damping force. The decrease in the supply of the working fluid as referred to herein can be understood as a decrease in the supply amount of the working fluid and also as a decrease in the supply pressure.

In the suspension control device according to the third aspect of the present invention, the supply / discharge suitability determination means determines the effectiveness of the supply / discharge control of the working fluid to / from the actuator. Then, when the supply / discharge suitability determination means determines that the supply / discharge control is not effective, the damping force change control means controls the damping force changing means in accordance with the road surface input, and the damping force generated by the actuator is input to the road surface input. Correspondingly, it is increased to the side where the damping property against the sprung vibration appearing on the spring is increased. For this reason, even if the effect of supply / discharge control is unsuitable for some unexpected reason and the desired support load increase / decrease cannot be obtained by the actuator through supply / discharge of the working fluid, the damping force generated by the actuator increases. Through the change, the damping property against sprung vibration can be enhanced and the damping force against sprung vibration can be secured. Further, the change of the damping force and the responsiveness of the actuator and the generated force are correlated with each other, and the responsiveness of the actuator and the generated force also increase with the change of the increase of the damping force. Here, the control for increasing the damping performance for the sprung vibration caused by the road surface input is mainly for improving the riding comfort of the vehicle, and this control is performed for the supply / discharge control of the working fluid and the change control of the damping force. If both are performed, the riding comfort may be impaired due to the above-mentioned correlation. For this reason,
The control for increasing the vibration damping property by increasing the damping force is executed only when the supply / discharge control of the working fluid is not effective.

The term "effective / unsuitable control of the supply / discharge of the working fluid to / from the actuator" means not only the case where the supply / discharge control by the supply / discharge means is low in effect because the supply of the working fluid is significantly reduced. It can be understood including the case where any of the controls themselves involved in the supply and discharge of the working fluid is disturbed and its effectiveness cannot be obtained. In other words, not only when the control by the supply and discharge means is hindered and its effectiveness cannot be obtained, but also when the working fluid supply source is hindered and the effectiveness of the supply of working fluid cannot be obtained, and when the running state is detected. In addition to the case where the supply / discharge control of the working fluid according to the running state cannot be obtained due to the trouble of the means, and the case where the effect cannot be obtained due to the trouble of the control itself by the supply / discharge control means. ..

In the suspension control device according to the fourth aspect, the damping force changing state monitoring means monitors the changing state of the damping force by the damping force changing means. Further, the damping force change adequacy determining means determines whether or not the damping force change means effectively changes the damping force. When the damping force change suitability determination means determines that the damping force change is not effective, the control amount when the supply / discharge control means controls the supply / discharge means is the damping force monitored by the damping force change state monitoring means. It is corrected by the control amount correction means according to the change state. Therefore, even if the effect of changing the damping force is unsuitable for some unexpected reason and the desired damping force cannot be generated by the actuator, the control amount of the supply / discharge means is changed according to the changing state of the damping force at that time. The responsiveness of the actuator and the generated force can be increased / decreased by performing the increase / decrease correction. Therefore, it is possible to compensate for the decrease in the vibration damping property and the restraint force of the posture change caused by the inadequate change of the damping force by the control amount of the supply / discharge means. It should be noted that the term "ineffectiveness of changing the damping force" as used herein means not only that the damping force changing means has a low effectiveness in changing the damping force, but also that the damping force changing means has a problem in obtaining the effectiveness thereof. It can be understood including cases where it is not possible.

In the suspension control device according to the fifth aspect, the supply / discharge control means and the damping force changing means are selected based on the supply / discharge control state of the working fluid to the actuator and the changing state of the damping force by the damping force changing means. Control. At this time, the harmony means controls the supply / discharge control means and the damping force changing means so that the effectiveness of the supply / discharge control and the effectiveness of changing the damping force can be harmonized. Therefore, if the supply / discharge control of the working fluid is not effective and the supporting load increase / decrease by the actuator is excessive or insufficient, the effectiveness of the supply / discharge control can be improved by changing the damping force by increasing the effectiveness of changing the damping force. Compensates for the unsuitable amount. If the control of the damping force changing means is unsuitable and there is an excess or deficiency in the damping force, the effectiveness of the control of the damping force changing means is unsuitable due to the increase or decrease in the supporting load brought about by increasing the effectiveness of the supply / discharge control. You can make up for it. In this case, the effectiveness of the supply / discharge control of the working fluid can be grasped as the effectiveness of the supply / discharge of the supply / discharge means or the control of the supply / discharge means of the supply / discharge control means.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the suspension control device according to the present invention will be described with reference to the drawings. The suspension control device of the present embodiment is configured as the fluid pressure active suspension 10 using a fluid pressure cylinder as follows.

FIG. 1 is a schematic configuration diagram showing a fluid circuit of a fluid pressure type active suspension 10 of an embodiment. As shown, the fluid pressure type active suspension 10
Includes a reservoir 11 that stores oil as a working fluid, and one end of a connection passage 12 and one end of a working fluid discharge passage 14 are connected to the reservoir 11. The other end of the connection passage 12 is connected to the suction side of a pump 18 driven by the engine 16. The pump 18 is a variable displacement pump in the illustrated embodiment, and one end of a working fluid supply passage 20 is connected to the discharge side thereof. The other end of the working fluid supply passage 20 and the other end of the working fluid discharge passage 14 are pilot-operated type 3 constituting a pressure control valve 22.
The port 3 position switching type switching control valve 24 is connected to the P port and the R port, respectively. The pressure control valve 2 is provided in the middle of each working fluid discharge passage 14 rather than the communication connection portion 14a where the working fluid discharge passages for other wheels join.
A check valve 15 is provided on the 2 side. Therefore, in the working fluid discharge passage 14, due to the check valve 15,
Only the flow of the working fluid from the pressure control valve 22 to the reservoir 11 is allowed.

The pressure control valve 22 includes a switching control valve 24, a branch passage 26 branching from the working fluid supply passage 20 to reach the reservoir 11, and a fixed throttle 2 provided in the middle of the passage.
8 and a variable throttle 30 that changes the effective passage cross-sectional area of the branch passage 26 by a built-in solenoid. The variable throttle 30 of the pressure control valve 22 is connected to an electronic control unit 100 described later, and when the electronic control unit 100 controls the current to the solenoid, it cooperates with the fixed throttle 28 to change the fixed throttle 28. Branch passage 26 to the throttle 30
The internal pressure Pp is changed. A connection passage 32 leading to an actuator 36 that is interposed between the vehicle body and the wheels and suspends the vehicle body is connected to the A port of the switching control valve 24. The switching control valve 24 of the pressure control valve 22 is a spool valve that takes in the pressure Pp as a pilot pressure through the fixed throttle 28 and the variable throttle 30 and the pressure Pa in the connection passage 32 through the throttle 34 of the passage. Yes, pressure Pp and pressure P
The direction of the oil flow is switched according to the balance with a, and the oil is supplied to and discharged from the actuator 36.

The other end of the connection passage 32 is communicatively connected to a working fluid chamber 38 of an actuator 36 provided corresponding to the wheel. As shown in the figure, the actuator 36 is a kind of cylinder piston device and is arranged between the suspension member 35 supporting the wheels Wh and the vehicle body to suspend the vehicle body. The actuator 36 variably generates a force that increases or decreases the support load of the vehicle body (sprung sprung) with respect to the unsprung portion by supplying / discharging the working fluid to / from the working fluid chamber 38. Increase or decrease the vehicle height of as follows.

Generally, the variable diaphragm 30 is the electronic control unit 100.
The solenoid is controlled to change the effective passage area of the branch passage 26. If the pressure Pp in the branch passage 26 and the pressure Pa in the connection passage 32 are equal when the effective passage cross-sectional area of the branch passage 26 has a certain value, the switching control valve 2
4 has a switching position 24b that shuts off communication with all ports.

When the variable throttle 30 is controlled by the electronic control unit 100 so that the pressure Pp becomes low, the pressure P
Since a becomes higher than the pressure Pp, the switching control valve 24 switches to the switching position 24c that connects and connects the port R and the port A, and keeps this position until the pressure Pa and the pressure Pp become equal. Therefore, the working fluid chamber 3 of the actuator 36
Oil is discharged from No. 8, and the actuator 36 reduces the supporting load of the vehicle body. Along with this, the vehicle height is lowered by the actuator 36.

On the other hand, the variable throttle 3 is used to increase the pressure Pp.
When 0 is controlled, the pressure Pa becomes lower than the pressure Pp, so that the switching control valve 24 switches to the switching position 24a that connects and connects the port P and the port A, and the pressure Pa and the pressure Pp.
Take this position until are equal. Therefore, oil is supplied from the pump 18 to the working fluid chamber 38 of the actuator 36, and the actuator 36 increases the supporting load of the vehicle body. Along with this, the actuator 36 increases the vehicle height.

A gas-liquid spring device 42 is connected to the working fluid chamber 38 by a passage 40.
Is a gas spring utilizing the elasticity of the enclosed nitrogen gas. The gas-liquid spring device 42 not only acts as a suspension spring or an auxiliary suspension spring, but also cooperates with the actuator 36 to variably generate the damping force of the suspension. A variable throttle 44 is provided in the middle of the passage 40, and the variable throttle 44 changes its effective passage cross-sectional area by a variable throttle actuator 45 to change the flow rate of the hydraulic oil in the passage 40. On the other hand, the piston 62 in the working fluid chamber 38 is fixed to the suspension member 35 at the lower end of the rod, and the piston 62 has a small-diameter working oil flow that allows the working oil to flow in the upper and lower oil chambers. The hole 64 is opened.

Accordingly, the gas-liquid spring device 42 variably generates the damping force of the suspension characteristic together with the actuator 36, and the damping force is changed via the variable throttle 44 driven by the variable throttle actuator 45. The variable diaphragm actuator 45 is used in the electronic control unit 100 described later.
And is controlled by the electronic control unit 100. Further, the variable diaphragm actuator 45 includes
Potentiometer 74 for detecting the drive position
(See FIG. 2) is provided, and the signal of the drive position of the variable diaphragm actuator 45 is input to the electronic control unit 100. The drive position of the variable throttle actuator 45 represents the opening degree of the variable throttle 44, that is, the damping force generated by the gas-liquid spring device 42 and the actuator 36.

Around the actuator 36 described above,
As illustrated, a vehicle height sensor 118 that detects the vehicle height of the vehicle body is disposed between the suspension member 35 and the vehicle body.

A pilot operated shutoff valve 46 is provided in the middle of the connection passage 32.
A pilot pressure Pc controlled by a pilot pressure control device 48 described later is taken in. And the shutoff valve 46 is
The valve opens when the pilot pressure Pc exceeds a predetermined valve opening value, and closes when the pilot pressure falls below a predetermined valve closing value. A pilot pressure control device 48 is provided in a connection passage 50 that connects the working fluid supply passage 20 and the reservoir 11 to each other. The pilot pressure control device 48 includes a fixed throttle 52 provided in the middle of the passage. And a variable throttle 54 that changes the effective passage cross-sectional area of the connection passage 50 with a built-in solenoid. The variable throttle 54 is connected to an electronic control unit 100 described later, and when the electronic control unit 100 controls the current to the solenoid, the fixed throttle 52 is connected.
The pressure Pc in the connecting passage 50 between the fixed throttle 52 and the variable throttle 54 is changed in cooperation with the above. Therefore, the pilot pressure control device 48 controls the pilot pressure P by the variable throttle 54.
c is changed and supplied to the shutoff valve 46, and the shutoff valve 46 opens or shuts off the connection passage 32 according to the pilot pressure Pc.

Further, in the middle of the working fluid supply passage 20,
A check valve 58 is provided which allows only the flow of working fluid from the filter 56 and pump 18 towards the pressure control valve 22. Further, an accumulator 60 and a pressure sensor 70 for detecting the system pressure in the suspension system of the present embodiment described above are connected to the working fluid supply passage 20 downstream of the check valve 58.

The above-mentioned pressure control valve 22, connection passage 32,
Variable throttle 44, actuator 36, gas-liquid spring device 4
2. The variable diaphragm actuator 45 and the like are provided for each wheel. In addition, these constituent members of each wheel (right front wheel, left front wheel, right rear wheel, and left rear wheel) are respectively denoted by a symbol F.
R, FL, RR, and RL are added, and for example, the pressure control valve 22 includes 22FR, 22FL, 22RR, and 2
It will be referred to as 2RL.

Next, the electrical construction of the fluid pressure type active suspension 10 will be described. As shown in FIG. 2, the pilot pressure control device 48 and the pressure control valve 22FL are used.
~ 22RR and variable diaphragm actuator 45FL ~ 4
The 5RRs are each connected to the electronic control unit 100. The electronic control unit 100 drives and controls the pilot pressure control device 48 and the variable throttle 54, the variable throttle 30, and each variable throttle actuator 45 included in each pressure control valve. The electronic control unit 100 includes a microcomputer 102 mainly including a central processing unit (CPU) 104. This microcomputer 10
2 is a CPU 104, a read-on memory (ROM) 106, and a random access memory (RA).
M) 108, an input port device 110, and an output port device 112, which are bidirectional common buses 114.
Are connected to each other by.

The input port device 110 has various switches and sensors such as a pressure sensor 70 and an E / G rotation speed sensor 72 for detecting the rotation speed of an engine E / G (not shown).
An ignition switch (IGSW) 116, potentiometers 74FL to 74RR for each wheel, vehicle height sensors 118FL to 118RR, a vehicle speed sensor 120 for detecting a vehicle speed, and a front-rear G for detecting an acceleration in the longitudinal direction of the vehicle body.
The (acceleration) sensor 122, the lateral G sensor 124 that detects the lateral acceleration of the vehicle body, the steering angle sensor 126 that detects the steering angle of the steering wheel, and the vehicle height control mode is either the high mode or the low mode. A vehicle height setting switch 128 to be set, vertical G sensors 140, 142, 144 provided corresponding to the left front wheel, the left rear wheel, and the right rear wheel to detect vertical acceleration acting on these wheels, and the vehicle body. A yaw rate sensor 146 that detects the acting yaw rate and a brake sensor 148 that detects the state of the depression operation of the brake are connected.

Then, the electronic control unit 100 determines whether various signals from these switches and sensors, specifically, a signal indicating the system pressure in the suspension system, a signal indicating the engine speed, and whether the ignition switch is in the ON state. Signal indicating that the vehicle height Xi (i = i) of the part corresponding to each wheel (left front wheel, right front wheel, left rear wheel and right rear wheel)
1, 2, 3, 4), a driving position of the variable diaphragm actuators 45FL to 45RR corresponding to each wheel, that is, a signal indicating the magnitude of the damping force of each wheel, a signal indicating the vehicle speed V, and a longitudinal acceleration of the vehicle body. A signal indicating Gx, a signal indicating the lateral acceleration Gy of the vehicle body, a signal indicating the steering angle θf of the steering wheel, a signal indicating whether the vehicle height control mode is the high mode or the low mode, each wheel (front left wheel, left wheel) A signal indicating the vertical accelerations Gza, Gzb and Gzc corresponding to the rear wheel and the right rear wheel), a signal indicating the state of the depression operation of the brake, etc. are input.

The input port device 110 appropriately processes the above-mentioned input signal and outputs the processed signal to the CPU and the RAM 108 according to an instruction of the CPU 104 based on a program stored in the ROM 106. The ROM 106 stores maps corresponding to the graphs shown in FIGS. 4 to 6 in addition to the control flow shown in FIG. 3 and the like and the control flow not shown in the drawings. It is supposed to process.
Further, the output port device 112, in accordance with the instruction from the CPU 104, passes through the drive circuit 130 and the pilot pressure control device 4
8 to output a control signal to the variable aperture 54, and drive circuit 132
Through 138 to output a control signal to the variable throttle 30 of the pressure control valves 22FL to 22RR, and via the drive circuits 150 to 156, the variable throttle actuator 45FL of each variable throttle 44.
The control signal is output to ~ 45RR.

Next, regarding the suspension control performed by the fluid pressure type active suspension 10 of the present embodiment,
This will be described with reference to the flowchart of FIG. The suspension control shown in the figure is started when the ignition switch 116 is turned on, and is ended shortly after the ignition switch is turned off.

As shown in FIG. 3, the first step S
At 50, the RAM 108 is initialized, and initial values are set for various flags, gains, and the like, which will be described later, which are used in damping force control amount calculation, active calculation, and the like, which will be described later. Then, it progresses to step S100. This initial value has a value of 0 for the flag and a reference value of each gain for the active control gain.

In step S100, a control signal is output to the solenoid of the variable throttle 54 of the pilot pressure control device 48 to gradually reduce the effective passage sectional area of the variable throttle, thereby gradually increasing the pilot pressure Pp. In this process, the shutoff valve 46 is opened, the pressure of the working fluid in the working fluid supply passage 20 reaches a predetermined pressure, and the shutoff valve 46 is fully opened, that is, the actuator 3
In the state in which the oil can be supplied to and discharged from 6, the process proceeds to the next step S150.

In step S150, the ignition switch 116 and the vehicle height sensor 11 for each wheel are
8, potentiometer 74, pressure sensor 70, E
/ G rotation speed sensor 72, vehicle speed sensor 120, longitudinal G sensor 122, lateral G sensor 124, steering angle sensor 126, vehicle height setting switch 128 and vertical G sensors 140 to 144.
The yaw rate sensor 146, the brake sensor 148, etc. are scanned, the corresponding signals are read from the respective switches and sensors, and then the process proceeds to step S200. That is, in step S150, a signal indicating the system pressure PS in the suspension system, a signal indicating the engine speed N, a signal indicating whether or not the ignition switch 116 is in the on state, a signal indicating the vehicle height Xi of each wheel, A signal indicating the magnitude of the damping force (driving position of the variable diaphragm actuator 45) on each wheel, a signal indicating the vehicle speed V,
A signal indicating the longitudinal acceleration Gx of the vehicle body, a signal indicating the lateral acceleration Gy, a signal indicating the steering angle θf of the steering wheel, a signal indicating whether the set mode is the high mode or the low mode, each wheel (left front wheel, Various signals such as signals indicating vertical accelerations Gza, Gzb, and Gzc corresponding to the left rear wheel and the right rear wheel) and a signal indicating the state of the depression operation of the brake are read.

Step S2 following this step S150
In step S150, the target damping force control amount CSO (the drive control amount of each variable throttle actuator 45 when changing the damping force via each variable throttle 44) for the purpose of ensuring steering stability is set in step S150. The calculation is performed as follows based on the read various signals. First, it is determined whether the turning situation of the vehicle is slow or fast based on the detection signals θf and V from the steering angle sensor 126 and the vehicle speed sensor 120, and the damping force (anti-roll) required to suppress the posture change of the vehicle in the turning situation. Calculate the number of steps of. In calculating the damping force step number, as shown in FIG. 4, a map corresponding to a graph of the product value of the vehicle speed V and the steering angle θf and the damping force step number is used. As a result, the number of damping force steps calculated for the anti-roll is the vehicle speed V and the steering angle θf.
The number of steps increases as the roll value becomes larger as the multiplication value of exceeds the predetermined value α1. The calculation of the damping force step number for this anti-roll may be performed using the product value of the vehicle speed V and the steering angular velocity instead of the product value of the vehicle speed V and the steering angle θf.

Further, based on the detection signals from the vehicle speed sensor 120 and the brake sensor 148, it is determined whether the dive is slow or fast, which is the difference between the vehicle height and the vehicle height. Calculate the number of steps of force (anti-dive). Also in this case, as shown in FIG. 5, a map corresponding to the graph of the vehicle height front-back difference and the damping force step number is used. As a result, the damping force step number calculated for the anti-dive gradually increases as the vehicle height front-back difference exceeds the predetermined value α 2. In addition, the vehicle height sensor 118 for each wheel
It can also be obtained from the detection signals Xi of FL to 118RR. Also, instead of the vehicle height front-back difference, the vehicle longitudinal acceleration Gx
Can also be used.

Further, based on the detection signals from the vehicle speed sensor 120 and the throttle opening sensor (not shown), it is discriminated whether the vehicle squart is gradual or not, and the damping force necessary for suppressing the vehicle attitude change in the squat situation. Calculates the number of steps (anti-squat). Even in this calculation, as shown in FIG. 6, a map corresponding to the graph of the throttle opening speed and the damping force step number is used. As a result, the damping force step number calculated for the anti-squat gradually increases as the throttle opening speed exceeds the predetermined value α3. It is also possible to correct this throttle opening speed by the vehicle speed V from the vehicle speed sensor 120 and obtain the damping force step number from the corrected throttle opening speed. Further, the longitudinal acceleration Gx of the vehicle can be used instead of the throttle opening speed.

Next, the maximum one of these three damping force step numbers is adopted as the target damping force step number CSso for the purpose of ensuring steering stability. Then, the drive control amount of the variable diaphragm actuator 45 for exhibiting the target damping force step number CSso is set as the target damping force control amount CSO.

In step S250 following the calculation of the target damping force control amount CSO in step S200, the correction calculation of the target damping force control amount CSO is performed as follows, and then the process proceeds to step S270. This step S250
First, as shown in the flowchart of FIG. 7 showing the detailed processing, the lower limit damping force guard value CGARD / LOW of the target damping force control amount is selected (step S252). That is,
Based on the signals (system pressure PS, engine speed N) read in step S150 and the maps corresponding to the graphs shown in FIGS. 8 and 9, the lower limit damping force guard value CGARD
Select / LOW. This lower limit damping force guard value CGARD / LOW
8 is selected as a large value if the system pressure PS or the engine speed N is low, as shown in FIGS. When selecting the lower limit damping force guard value CGARD / LOW, one of the map corresponding to the graph shown in FIG. 8 and the map corresponding to the graph shown in FIG. 9 may be used.

Here, the graphs of FIGS. 8 and 9 will be briefly described. The engine speed N and the discharge capacity (discharge amount, discharge pressure) of the pump 18 are in a proportional relationship, and the lower the engine speed N, the lower the discharge capacity of the pump 18. Therefore, as shown in FIG. 8, if the engine speed N decreases, the amount of hydraulic oil that can be supplied to the actuator 36 also decreases. Therefore, when the engine rotation speed N is relatively low and drops below a certain rotation speed N0 and the supply amount of hydraulic oil to the actuator 36 is expected to decrease, the lower limit damping force guard value CGARD / LOW is set. Is a large value.

Regarding the system pressure PS, it is necessary to control the pressure control valve 22 according to the comparison with the pressure in the working fluid chamber 38 of the actuator 36. Therefore, as shown in FIG. 9, when the system pressure PS decreases at a relatively high system pressure PS0, the lower limit damping force guard value CGARD / LOW becomes a large value.

Following step S252, the target damping force control amount CSO calculated in step S200 is compared with the lower limit damping force guard value CGARD / LOW (step S).
254). If it is determined that the target damping force control amount CSO is equal to or more than the lower limit damping force guard value CGARD / LOW, the target damping force control amount CSO is set to the final target damping force control amount MCFINAL (step S256), and thereafter, Step S27
Move to 0. On the other hand, when it is determined in step S254 that the target damping force control amount CSO is below the lower limit damping force guard value CGARD / LOW, the lower limit damping force guard value CGARD / LOW is set to the final target damping force control amount MCFINAL (step S25
8) Then, the process proceeds to step S270.

Therefore, steps S252 to S252 shown in FIG.
By the processing up to 258, the damping force is limited as follows. That is, if the target damping force control amount CSO once determined from the viewpoint of steering stability falls below the lower limit damping force guard value CGARD / LOW determined by the engine speed N or the system pressure PS at that time as shown in FIG. 8 or FIG. , Target damping force control amount CSO
The lower limit damping force guard value CGARD / LOW is used instead.
Thus, the target damping force control amount CSO is the engine speed N
Alternatively, the damping force is set to a larger value because the lower limit is limited by being corrected according to the system pressure PS.

In step S270, which follows step S250 including the series of processes described above, it is determined whether or not the active suspension control for supplying / discharging hydraulic fluid to / from the actuator 36 via the pressure control valve 22 is hindered. Then, according to the determination result, step S300
Alternatively, the process proceeds to either step S400. In this case, the determination as to whether or not the active suspension control is disturbed is performed as follows. For example, the transition of the output signal (system pressure PS) from the pressure sensor 70 is monitored, and if the system pressure PS does not rise to the predetermined pressure even after a predetermined time has elapsed since the start of this routine, the active suspension control is performed. Judge that there is a problem. Alternatively, if this routine is being executed, it is determined that active suspension control is hindered when the system pressure PS suddenly drops or rises. When it is determined that the active suspension control is impaired in this way, a warning light to that effect is turned on, and the occupant is warned.

If it is determined in step S270 that the active suspension control is hindered, the shutoff valve 46 upstream of the actuator 36 is closed in step S300. Specifically, a control signal is output to the solenoid of the variable throttle 54 of the pilot pressure control device 48 to rapidly increase the effective passage cross-sectional area of the variable throttle, thereby reducing the pilot pressure Pp. In this process, the shutoff valve 46 is closed.

That is, in this step S300, the shut-off valve receives the determination (control is impaired) in the previous step S270, and thereafter it is not necessary to perform the active control calculation described later, that is, the active suspension control. 46 is closed. Even in this case,
Since the actuator 36 suspends the vehicle body independently at each wheel as a closed system, the actuator 36 exhibits the same function as a suspension as a vehicle without an active suspension. Further, the actuator 36 is
Since the gas-liquid spring device 42 is provided, it functions as a hydropneumatic suspension.

Subsequent to step S300, the target damping force control amount CNO for the purpose of ensuring the riding comfort is calculated in step S310, and the target damping force control amount is determined in step S320, and thereafter step S330. Proceed to. In this step S330, since it is determined in step S270 that there is a problem in the active suspension control, the active control amount calculated in this routine up to the previous time (control target pressure Puj in each actuator 36 controlled by each pressure control valve) Is initialized, and thereafter, the process proceeds to step S600, which will be described later, for outputting a control signal. It should be noted that the reason why the active control amount is initialized in step S330 is that it is not necessary to drive-control the pressure control valve 22 when the active suspension control is disturbed. However, even if step S330 is omitted and the pressure control valve 22 is driven by the active control amount up to that point in step S600, there is no effect because the shutoff valve 46 is shut off in step S300.

Here, the processing of these steps S310 and 320 (calculation of the target damping force control amount CNO and its determination)
Will be described with reference to the flowcharts of FIGS. 10 and 11 showing the detailed processing thereof. Prior to the detailed description thereof, the damping force calculation flag fNO in the processing of the flowchart will be described. This damping force calculation flag fNO
Indicates whether the transition of the damping force change for ensuring the riding comfort is at a stage of maintaining, increasing / holding or decreasing the damping force. Then, as shown in FIG. 12, the damping force calculation flag fNO indicates that the damping force is maintained in the first step if the value is 1, and the damping force is calculated if the value is 2. It shows that it is in the second stage of increasing / holding, and if the value is the value 3, it is in the third stage of gradually reducing the damping force. Further, the damping force calculation flag fNO is initially set to an initial value "zero" in step S50, and if the value is zero, it indicates that there is no stage. That is, if the damping force calculation flag fNO = 0, it means that the calculation of the target damping force control amount CNO is unnecessary.

In the calculation of the target damping force control amount CNO in step S310, first, as shown in FIG. 10, the vertical acceleration Gz (Gza, Gzb, Gzc) read from the vertical G sensors 140 to 144 in step S150 is low-passed. Filter processing is performed (step S332). This low-pass filter processing can be realized by the following mathematical formula,
By performing the processing, the sprung resonance of the vehicle body is extracted.

GzL = GzL + (Gz−GzL) · KLPF Equation (1)

GzL in the above equation is the vertical acceleration obtained by the filtering process, and KLPF is the constant of the filter.

After that, the sprung resonance GzL obtained by the filter processing is compared with a predetermined comparison value GzL0 (step S334). Is a medium (step S336). On the other hand, when a negative determination is made in step S334, the vertical acceleration Gz is set to be negligibly small, and the virtual target damping force mCNO is set to zero (step S338). in this case,
The virtual target damping force mCNO, which is defined when an affirmative determination is made in step S334, may be a multistage damping force according to the magnitude of the sprung resonance GzL.

After the virtual target damping force mCNO is thus defined, it is determined whether or not the virtual target damping force mCNO is larger than the reference virtual target damping force mCNO / base set in the present routine of the past (step S340). ). Here, if a negative determination is made, the process proceeds to step S348 described later, and if a positive determination is made, it is determined whether or not the value of the damping force calculation flag fNO is zero (step S342). This step S3
If the affirmative determination is made (fNO = 0) in 42, this routine of this time is the first determination in step S270 that there is a problem in the active suspension control. Therefore,
In this case, the damping force calculation flag fNO is set to the value 1 (step S344), and the virtual target damping force mCNO defined in any of steps S336 and 338 is set as the reference virtual target damping force mCNO / base (step S346). . On the other hand, if a negative determination is made in step S342, this routine of this time is during the change transition of the damping force, and therefore the process immediately proceeds to step S346.

That is, the above steps S340 to 346.
By the processing up to, the reference virtual target damping force mCNO / base
Is updated each time an affirmative determination is made in step S340, so the virtual target damping force m before this routine is executed.
It is the maximum value of CNO.

Following step S346 or following the negative determination (mCNO≤mCNO / base) in step S340, the value of the damping force calculation flag fNO is 2 or more, and the virtual target damping force mCNO is medium or more. It is determined whether or not it is a damping force (step S348). If a negative determination is made here, the process proceeds to step S352 described later, and if a positive determination is made, the damping force calculation flag fNO is set to the value 2 and the timer t is set to zero to initialize it (step S).
350). Note that after step S346 has been performed after fNO = 1 is set in step S344, step S348 is performed.
Since a negative determination is made, the value of the damping force calculation flag fNO remains 1.

After that, the value of the damping force calculation flag fNO is 1
Is determined (step S352), and if a negative determination is made, the process proceeds to step S360, which will be described later, shown in FIG. On the other hand, in this step S352, an affirmative judgment (fNO =
In the case of 1), the timer t is incremented (step S352), and it is determined whether or not the value of the timer t is equal to or longer than the predetermined delay time tdelay (step S356). If a negative determination is made here, the process proceeds to step S360 in FIG. 11, and if an affirmative determination is made, the damping force calculation flag fNO is set to value 2 and the timer t is set to zero to initialize it (step S358). Note that in steps S360 and S368 after step S358, if the value of the damping force calculation flag fNO is 1, a negative determination is made and the process proceeds to step S382.

Therefore, if the damping force calculation flag fNO is set to the value 1 in step S344 and remains unchanged, the value of the increment of the timer t is delayed by the negative determination in step S348 and the positive determination in step S352. It continues until tdelay is reached. When the delay time tdelay has elapsed, the damping force calculation flag fNO is changed from 1 to 2 (step S358). That is, the above-described processing from steps S342 to 358 is processing for maintaining the damping force calculation flag fNO set to the value 1 in step S344 as it is, and during that period, the target damping force control amount CNO is calculated. Absent. As a result, even if the active suspension control is hindered in step S270, the damping force is not changed over the initial delay time tdelay, and the system waits for the delay time tdelay.

Following step S358 or following the negative judgment in step S352, as shown in FIG. 11, it is judged whether or not the value of the damping force calculation flag fNO is 2 (step S360), and the negative judgment is made. If so, the process proceeds to step S368 described below. On the other hand, if an affirmative determination (fNO = 2) is made in step S360, the timer t is incremented and the target damping force control amount CNO is set to the reference virtual target damping force mCNO / bas defined in step S346.
e (step S362). In this case, since the reference virtual target damping force mCNO / base is the maximum value of the virtual target damping force mCNO obtained in steps S336 and 338, the target damping force control amount CNO is also the damping force of this value.

Subsequent to step S362, it is determined whether or not the value of the timer t is equal to or longer than a predetermined hold time thold (step S364). If a negative determination is made here, the process proceeds to step S368, which will be described later.
Is set to zero to initialize it (step S36).
6). It should be noted that step S3 after this step S366
At 68, if the value of the damping force calculation flag fNO is 1 or 2, a negative determination is made and the routine goes to step S382.

Therefore, if the damping force calculation flag fNO is changed from the value 1 to the value 2 in step S358 and remains as it is,
By the affirmative determination in step S360, the increment of the timer t is continued until the value reaches the hold time thold, during which the target damping force control amount CNO is calculated (step S362). Then, after the hold time has elapsed, the damping force calculation flag fNO is changed from 2 to 3. That is, the damping force calculation flag fNO set to 1 in step S344 is changed to the value 2 in the processes of steps S360 to 366, and the target damping force control amount C is set in the meantime.
Calculate NO. As a result, after delaying the active suspension control, the delay time tdelay
After the standby, the target damping force control amount CNO is calculated according to the vertical acceleration in order to increase and decrease the damping force for ensuring the riding comfort. Moreover, the calculated target damping force control amount CNO is held as the control amount (reference virtual target damping force mCNO / base) corresponding to the maximum value of the virtual target damping force mCNO.

Following step S366 or following the negative determination in step S360, the damping force calculation flag f
It is determined whether the value of NO is 3 (step S36).
8) If negative, the process proceeds to step S382. On the other hand, when an affirmative determination (fNO = 3) is made in step S368, the timer t is incremented (step S370). Next, it is determined whether the value of the timer t is equal to or longer than the predetermined down time tdown (step S37).
2). If a negative determination is made here, the process proceeds to step S378, which will be described later, and if a positive determination is made, the timer t is set to zero and initialized (step S374).

After that, the target damping force control amount CNO at that time
Is reduced by ΔC to obtain a new target damping force control amount C
It is set to NO (step S376), and it is determined whether or not the new target damping force control amount CNO is zero or less (step S378). If a negative determination is made here, the process proceeds to step S382, and if a positive determination is made, the reference virtual target damping force mCNO / b.
ase, target damping force control amount CNO, and damping force calculation flag f
Both NO are set to zero and these are initialized (step S380). After that, it transfers to step S382.

Therefore, if the damping force calculation flag fNO is changed from the value 2 to the value 3 in step S366 and remains unchanged,
By the affirmative determination in step S368, the increment of the timer t is repeatedly continued until the value reaches the down time tdown, and each time the down time tdown is reached,
The target damping force control amount CNO is gradually reduced by ΔC.
When the target damping force control amount CNO is calculated to be zero or less than this, the above initialization is performed in step S380. That is, in the above-described processing of steps S370 to 380, the damping force calculation flag fNO set to the value 2 in step S366 is changed to the value 3, and the target damping force control amount CNO is gradually reduced during that period. As a result, after the active suspension control is hindered and the damping force is temporarily increased and held, the target damping force control amount CNO is subtracted to stepwise reduce the damping force (step S376). ).

Therefore, when the active suspension control is hindered, the sprung resonance GzL is equal to the predetermined comparison value G.
When it becomes zL0 or more, instead of active suspension control, the damping force is increased and changed, and then held and reduced in order to exert damping performance against vertical vibration of the vehicle body. At this time, as shown in FIG. 12, the delay time t
After waiting for a delay, the target damping force control amount CNO is increased, and the value is held for the hold time thold. After that, the target damping force control amount CNO is subtracted. On the other hand, if the sprung mass resonance GzL is small enough to be ignored even if the active suspension control is disturbed, the virtual target damping force mCNO remains zero and the calculated target damping force control amount CNO is also zero.

After calculating the target damping force control amount CNO in this way, the process proceeds to step S382 which is a detailed process of step S320 in FIG. 3 to determine the target damping force control amount. That is, in steps S200 and S250, the target damping force control amount CSO for ensuring the steering stability is calculated regardless of whether or not there is any obstacle in the active suspension control. Therefore, either the target damping force control amount CSO or the target damping force control amount CNO for the purpose of ensuring the riding comfort is determined as the control amount when actually outputting.

Then, in step S382, which is the first process of step S320, the above-described step S of FIG.
Final target damping force control amount MCFI set by 256, 258
NAL (Target damping force control amount CSO or Lower limit damping force guard value CG
ARD / LOW) and the target damping force control amount CNO calculated above are compared. Here, the set final target damping force control amount MC
If it is determined that FINAL is greater than or equal to the target damping force control amount CNO, in step S384, the set final target damping force control amount MCFINAL is adopted as it is, and then the process proceeds to step S600. This is because the final target damping force control amount MCFINAL that has been set can be used to exhibit the damping property against vertical vibration of the vehicle body. On the other hand, step S382
If it is determined that the final target damping force control amount MCFINAL which has been set in step 3 is less than the target damping force control amount CNO, step S38.
At 6, the target damping force control amount CNO is set to the final target damping force control amount MCFINAL, and then the process proceeds to step S600 via step S330.

In step S600, the control signal corresponding to the target damping force control amount (final target damping force control amount MCFINAL) obtained as described above is supplied to the drive circuit 15 corresponding to each variable throttle actuator 45FL to 45RR.
0 to 156, and a control signal corresponding to the active control amount (control target pressure Puj in each actuator 36 controlled by each pressure control valve) obtained by the active control amount calculation described later is output to each pressure control valve. 22 FL ~ 2
It outputs to the drive circuits 132 to 138 corresponding to 2RR.
The pressure control valves 22FL to 22R are output via the output of this control signal.
The R and variable diaphragm actuators 45FL to 45RR are drive-controlled, and thereafter the process returns to step S150. However, as described above, in step S600 after the processing in steps S300 to 330 is performed following the positive determination in step S270, the active control amount (control target pressure Puj) is initialized in step S330. Therefore, the pressure control valves 22FL to 22RR are not driven.

Therefore, while the active suspension control is hindered, the shutoff valve 46 for each wheel is kept closed in step S300, and in that state, damping for ensuring steering stability is performed in step S200. The force calculation is performed in step S250, the correction is performed in step S310, the damping force calculation is performed in step S310 to secure the riding comfort, and the final damping force determination calculation is performed in step S320. And during this time, without active suspension control,
The damping force generated by the actuator 36 of each wheel and the gas-liquid spring device 42 is controlled to a damping force corresponding to the final target damping force control amount MCFINAL determined in step S320.

On the other hand, when it is determined in step S270 of FIG. 3 that the active suspension control is not hindered,
In step S400, various gains necessary for active control, which will be described later, are calculated, and then the process proceeds to step S500. Then, in step S500, active calculation is performed based on the various signals read in step S150 to perform active suspension control for vehicle body height maintenance control, attitude control, and vehicle ride comfort control, and the active control amount is controlled. (Control target pressure Puj) is calculated.

Regarding the active control gain calculation, referring to the flow charts of FIGS. 13 to 14 and the graphs of FIGS. It will be described in detail later with reference to the flowchart of FIG. 21 and the graphs of FIGS. In step S600 subsequent to steps S400 and 500, as described above, the control signal corresponding to the active control amount and the control signal corresponding to the target damping force control amount are output. Then, the pressure control valves 22FL to 22RR and the variable throttle actuators 45FL to 45RR are drive-controlled via the output of this control signal, and thereafter the process returns to step S150. In this case, since it is determined in step S270 that the active suspension control is not hindered, steps S200, 25
The final target damping force control amount MCFINAL (target damping force control amount CSO or lower limit damping force guard value CGARD / LOW) for ensuring steering stability obtained at 0 is output as it is, and the variable throttle actuators 45FL to 45RR are drive-controlled. It

Next, the active control gain calculation in step S400 will be described. Step S400
As shown in the flowchart of FIG. 13 showing the detailed processing of No. 1, first, it is determined whether the damping force control is disturbed (step S402). The determination as to whether or not the damping force control is hindered is performed as follows. For example, step S2
If the difference between the target damping force control amount CSO calculated at 00 and the output result of the potentiometer 74 of each variable throttle actuator 45 is outside the predetermined allowable range, the variable throttle actuator 45 is correctly driven with respect to the control amount. If not, it is determined that the damping force control is hindered. Alternatively,
When the output of the potentiometer 74 changes irregularly or in a peculiar form, it is determined that the damping force control is impaired. When it is determined that the damping force control is impaired in this way, a warning light indicating that fact is lit up, and the occupant is warned.

If a negative determination is made in step S402 and there is no hindrance to the damping force control, it is necessary to carry out damping force processing at the time of a later-described damping force control hindrance and special active control gain calculation according to the degree of the hindrance. do not do. Therefore, in this case, the process proceeds to step S442, which will be described later, shown in FIG. 14, and the gain calculation is promptly performed when the damping force control is not hindered. On the other hand, when an affirmative determination is made in step S402, it is determined which of the front and rear wheels has the damping force control failure. First, it is determined whether or not the wheel in which the damping force control is impaired is the left front wheel, and the detection signal of the potentiometer 74FL for this left front wheel and its target damping force control amount C.
The determination is made based on SO (step S404). here,
If an affirmative determination is made, the following "damping force process during trouble (step S410)" is performed.

First, it is judged whether or not the current damping force CT indicated by the detection signal of the potentiometer 74FL is within the range from the control lower limit damping force Cmin during failure to the control upper limit damping force Cmax during failure (step). S412). The lower limit or the upper limit damping force Cmin, Cmax is the damping force before reaching the lowest limit damping force (full soft) or the highest limit damping force (full hard) that can be generated by the actuator 36 and the gas-liquid spring device 42. Stipulated as. If an affirmative decision is made in step S412, the damping force CFR of the right front wheel that does not hinder the damping force control is set as the current damping force CT of the left front wheel that hinders the control (step S4).
414). On the other hand, following the negative judgment in step S412, it is judged whether or not the current damping force CT of the left front wheel exceeds the control upper limit damping force Cmax at the time of obstacle (step S416),
If an affirmative determination is made, the damping force of the front right wheel is set as the control upper limit damping force during failure Cmax (step S418). Furthermore, if a negative determination is made in step S416, the damping force of the right front wheel is set as the obstacle control lower limit damping force Cmin (step S420).

That is, in the damping force processing at the time of failure when the damping force control is impaired on the left front wheel, the damping force CFR for the right front wheel, which does not interfere with the damping force control, is changed to the current damping force C for the left front wheel.
Depending on T, the present damping force CT, the control upper limit damping force Cmax during failure or the control lower limit damping force Cmin during failure is set. On the other hand, the damping force of the left front wheel remains unchanged.

Subsequent to the damping force control at the time of failure, a value 1 is set to the front wheel failure flag fCF indicating that the failure of the damping force control has occurred on the front wheels (step S422).
The front wheel trouble flag fCF is set to an initial value 0 by the initialization in step S50.

On the other hand, following the negative determination in step S404 (the front left wheel has no problem), it is determined whether the right front wheel has a problem in damping force control (step S424). If an affirmative decision is made here, the above-described obstacle damping force processing (step S410) is carried out on the assumption that the right front wheel has an obstacle in damping force control. In other words, the damping force for the right front wheel that has an obstacle in damping force control is set as the current damping force CT, while the damping force CFL for the left front wheel that does not interfere with damping force control is set as the present damping force CT. Either the control upper limit damping force Cmax or the control lower limit damping force Cmin at the time of trouble is set. After that, the process proceeds to step S422, and the front wheel obstacle flag fCF
Set the value 1 to.

Following the negative determinations in steps S404 and 424 (the left and right front wheels are not impaired), it is determined whether the left rear wheel is impaired in damping force control (step S4).
26). If an affirmative determination is made here, the above-described obstacle damping force processing (step S410) is performed assuming that the left rear wheel has an obstacle in damping force control. That is, the damping force of the left rear wheel that has a problem in damping force control is the current damping force CT, while the damping force CRR of the right rear wheel that has no problem in damping force control is the current damping force CT, Either the control upper limit damping force during failure Cmax or the control lower limit damping force during failure Cmin is set. After that, a value 1 is set to the rear wheel trouble flag fCR indicating that the rear wheel has trouble in damping force control (step S428). In addition, this rear wheel obstacle flag fC
R is also initialized to 0 in step S50.

Further, steps S404, 424, 426.
If a negative determination is made (no problem in the left and right front wheels and the left rear wheel) in any of the steps, together with the positive determination (the damping force control is disturbed) in step S402,
This means that the right rear wheel has an obstacle in damping force control. Therefore,
In this case, the above-mentioned obstacle damping force processing (step S4)
10) is performed assuming that the damping force control is impeded on the right rear wheel. That is, the damping force for the right rear wheel that has a problem in damping force control is the current damping force CT, while the damping force CRL for the left rear wheel that does not interfere with the damping force control is the current damping force CT, Either the control upper limit damping force during failure Cmax or the control lower limit damping force during failure Cmin is set. After that,
In step S428, the rear wheel obstacle flag fCR is set to the value 1.

As described above, when the front wheels have a difficulty in controlling the damping force, the damping force for the rear wheels is not subjected to the failure-time damping force processing. Further, when the rear wheels have a difficulty in controlling the damping force, the damping force for the front wheels is not subjected to the failure-time damping force processing. It should be noted that since there is very little trouble in damping force control for both the front and rear wheels, a description of that case is omitted in this embodiment. However, in order to cope with this, it is possible to determine whether or not the rear wheels have an obstacle in damping force control, following the obstacle damping force processing for the front wheels and the setting of the flag in step S422. Good. Then, according to the determination result, the damping force processing at the time of trouble may be performed on the rear wheels.

Steps S422 and S4 in which the corresponding flag is set to the front wheel or the rear wheel as an obstacle to the damping force control
Following step 28, the active control gain is calculated as follows. First, as shown in FIG. 14, with respect to the wheel having an obstacle in damping force control, the damping force deviation between the final target damping force control amount MCFINAL and the current damping force CT in step S250 is calculated (step S430). Next, the damping force for each wheel that is determined to have any obstacle in damping force control (either the current damping force CT, the obstacle control upper limit damping force Cmax, or the obstacle control lower limit damping force Cmin)
Is the final target damping force control amount MCFI in step S250.
Final target damping force control amount MCFINA to be output instead of NAL
L (step S432).

Here, step S432 will be described by taking as an example the case where the damping force control is impeded by the left front wheel.
Final target damping force control amount MC for the left front wheel in this case
FINAL is the current damping force CT. If the present damping force CT is within the range of the control lower limit damping force Cmin during failure to the control upper limit damping force during failure Cmax, the final target damping force control amount MCFINAL for the right front wheel is determined in step S414.
It is assumed that the current damping force CT is the same as that of the left front wheel determined in. Also,
If the present damping force CT exceeds the control upper limit damping force Cmax at the time of obstacle, the final target damping force control amount M for the right front wheel is obtained.
C FINAL is the obstacle control upper limit damping force Cmax determined in step S418. Further, if the present damping force CT is below the obstacle control lower limit damping force Cmin, the final target damping force control amount MCFINAL for the right front wheel is determined in step S42.
The control lower limit damping force Cmin is set to 0. In these cases, if the damping force control is not impaired on any of the rear wheels, the final target damping force control amount MCFI for the left and right rear wheels is set.
NAL is the final target damping force control amount M in step S250.
It remains C FINAL.

If there is no problem in the damping force control for both the front and rear wheels (negative determination in step S402), the process is not performed because the process does not proceed to step S432. Therefore, the final target damping force control amount MCFINAL for the left and right wheels in this case remains the final target damping force control amount MCFINAL in step S250.

Subsequent to step S432, it is determined whether or not the value of the front wheel obstacle flag fCF is 1 (step S434), and it is determined whether the damping force control of the front wheel is disturbed. In the following explanation,
For the sake of convenience, the case where either the left or right front wheel has a problem in damping force control will be described first.

Here, the active control gain calculated according to the degree of the obstacle when the damping force control is disturbed will be described in advance. The main active control gains targeted by this calculation are as follows.

-Proportional term gains Kzpf, Kzpr of displacements corresponding to vehicle height values on the front and rear wheels (vehicle height corresponding displacements) -Differential term gains K of vehicle height value corresponding displacements on the front and rear wheels
zdf, Kzdr ・ Integral term gain K of displacement corresponding to vehicle height values on the front and rear wheels
zif, Kzir ・ Proportional term gains Kpgpf, Kpgrf, Kpgpr of horizontal accelerations on the front and rear wheels of the vehicle with respect to roll and pitch,
Kpgrr ・ Differential term gain Kdgpf, Kdgrf, Kdgpr of horizontal acceleration on the front wheel side and rear wheel side of the vehicle body with respect to roll and pitch,
Kdgrr-Roll stiffness distribution gain K1f, K1r, K2f, K2r between front and rear wheels for front and rear wheels

As described above, when the front wheels have a difficulty in controlling the damping force, the front wheel failure flag fCF = 1 is set in step S422 of FIG. Therefore, in this case, an affirmative determination is made in step S434, and thereafter, the above-described gain calculations are performed as follows (step S
436).

First, based on the damping force deviation (MCFINAL-CT) calculated in step S430 and the maps corresponding to the graphs shown in FIGS. 15 and 16, the correction coefficient for correcting each gain described above is obtained. Specifically, a correction coefficient Kifh (i = 1, 2) for correcting the roll rigidity distribution gains K1f, K2f for the front wheels is obtained from the damping force deviation and FIG. 15, and the other gains described above are corrected. The correction coefficient Kh is calculated from the damping force deviation and FIG. Then, the reference value (K1f
0, K2f0, Kzpf0, Kzpr0, Kzdf0, Kzdr0, Kzif0,
Kzir0, Kdgpf0, Kdgpr0, Kdgrf0, Kdgrr0) and the obtained correction coefficients are used to calculate the respective gains according to the following mathematical expressions.

K1f = K1f0 · K1fh (2) K2f = K2f0 · K2fh (3) K1r = 1−K1f (4) K2r = 1−K2f (5) Kzpf = Kzpf0 · Kh (Equation) (6) Kzpr = Kzpr0.Kh ... Equation (7) Kzdf = Kzdf0.Kh ... Equation (8) Kzdr = Kzdr0.Kh ... Equation (9) Kzif = Kzif0.Kh .. (11) Kdgpf = Kdgpf0.Kh ... Formula (12) Kdgpr = Kdgpr0.Kh ... Formula (13) Kdgrf = Kdgrf0.Kh ... Formula (14) Kdgrr = Kdgrr0.Kh ... Formula (15)

The proportional term gain Kpg of the horizontal direction acceleration
Although pf, Kpgrf, Kpgpr, and Kpgrr remain their reference values, they can be calculated with the correction coefficient Kh as in the above gain.

Subsequent to the gain calculation in step S436, it is determined whether or not the value of the rear wheel obstacle flag fCR is 1 (step S438). This is to determine whether the damping force control is hindered not only for the front wheels but also for the rear wheels. When only the front wheels have a problem in damping force control, a negative determination is made in step S438, and the process proceeds to step S442, which will be described later. If the damping force control is hindered in both the front and rear wheels, an affirmative decision is made in step S438, and a step S, which will be described later, is performed in order to perform a gain calculation when the rear wheel is hindering the damping force control.
Move to 440.

Next, the case where the damping force control is hindered only by the rear wheels will be described. In this case, the rear wheel obstacle flag fCR is set to 1 in step S428 of FIG. 13, and the front wheel obstacle flag fCF remains at 0. Therefore, in this case, a negative determination is made in step S434, and thereafter,
As in step S432, the damping force deviation and the deviations in FIG. 16 and FIG.
After obtaining the correction coefficient based on the map corresponding to the graph shown in FIG. 7, each gain is calculated according to the same mathematical expressions as the mathematical expressions (2) to (15) (step S44).
0). The graph of FIG. 17 used for this gain calculation is a graph for obtaining the correction coefficient Kifh when the rear wheel has a problem in damping force control. The slope has the opposite sign.

Further, when the affirmative judgment is made in step S438, the gain calculation in step S436, which is performed assuming that the front wheels have a difficulty in the damping force control, is followed by the above steps when the rear wheels have a difficulty in the damping force control. The process moves to S440. Then, if the front and rear wheels have a difficulty in controlling the damping force, the processing of steps S436 and 440 is performed.

Thus, steps S430 to S4
After performing the gain calculation according to the presence / absence of the damping force control failure in the processing up to 40, it is determined whether the front wheel failure flag fCF and the rear wheel failure flag fCR are both 1 (step S442). To do. This is to determine whether any of the front and rear wheels has a problem in damping force control.

When a negative determination is made in step S442, the process proceeds to step S500 in FIG. 3 without performing the processes of step S444 and thereafter. In other words, in this case, the active control gain in the processing from step S430 to step S440, which is performed because there is a problem in the damping force control in one of the front and rear wheels, is used for the active control amount calculation in step S500. Then, in the active control amount calculation, the active control gain calculated according to the presence / absence of the obstacle of the damping force control is used.

Following the affirmative judgment in step S442 (no problem in damping force control), the final target damping force control amount MCFINAL or the current damping force CT in step S250 and FIG.
Based on the map corresponding to the graph shown in FIG. 8, the target gain mK of each gain described above is calculated (step S44).
4). The graph of FIG. 18 shows the gain for each active control gain or the gain related to the vehicle height value corresponding displacement,
It is prepared for each gain related to horizontal acceleration and roll rigidity distribution.

Following step S444, the obtained target gain mK and the current gain KLI of each active control gain are calculated.
It is determined whether or not VE is equal (step S446), and if both gains are equal, it is determined that correction of the current gain is unnecessary and the process proceeds to step S500. On the other hand, if the gains are not equal, the target gain mK and the current gain KLIVE are compared in size (step S448), and the current gain KLIVE is increased or decreased according to the result. That is, if the target gain mK is large, the current gain KLIVE is increased by ΔK (step S450), and if the target gain mK is small, the current gain KLIVE is decreased by ΔK (step S452). When the active control gain is calculated in this way, the process proceeds to step S500.

Next, an example of the active control amount (control target pressure Puj) calculation performed in step S500 will be described with reference to FIGS. 19 to 21.

As shown in FIG. 19, in step S502 which is the first process of step S500, the heave target value Rxh based on the target attitude of the vehicle body is set to the vehicle speed V as shown in FIG.
Calculated based on the map corresponding to the graph shown in
After that, the process proceeds to step S504. 22. In FIG. 22, the pattern of the heave target value Rxh when the vehicle height control mode set by the vehicle height setting switch 128 is the normal mode is shown by a solid line, and the pattern when the vehicle is in the high mode is shown by a dotted line. .

In step S504, step S
Left front wheel, right front wheel, left rear wheel, read in 150,
Based on the vehicle heights X1 to X4 at the position corresponding to the right rear wheel, the displacement mode conversions for heave (Xxh), pitch (Xxp), roll (Xxr), and warp (Xxw) are calculated according to the following formulas. It proceeds to step S506.

Xxh = (X1 + X2) + (X3 + X4) Formula (16) Xxp =-(X1 + X2) + (X3 + X4) Formula (17) Xxr = (X1-X2) + (X3-X4) ... Formula (18) Xxw = (X1-X2)-(X3-X4) Formula (19)

In step S506, the deviation of the displacement mode is calculated according to the following equation, and then the process proceeds to step S508. In calculating the deviation in the displacement mode, the vehicle height control mode and the vehicle speed V are determined in step S502.
The heave target value Rxh calculated according to the above is used.

Exh = Rxh−Xxh Equation (20) Exp = Rxp−Xxp Equation (21) Exr = Rxr−Xxr Equation (22) Exw = Rxw−Xxw Equation (23)

In this case, the pitch target value Rxp and the roll target value Rxr may be zero. Also, the warp target value R
xw may also be 0, or may be Xxw calculated in step S504 immediately after the activation of the active suspension or an average value of Xxw calculated in the past several cycles. The absolute value of Exw (| Exw |) ≤
In the case of W1 (a positive constant), Exw = 0.

In step S508, the displacement mode gain is calculated according to the following equation, and then the process proceeds to step S510. In the displacement mode gain calculation, the displacement mode deviations calculated in step S506 are used.

EHS = Exh.SEGH ... Equation (24) EPS = Exp.SEGP ... Equation (25) ERS = Exr.SEGR ... Equation (26) EWS = Exw.SEGW ... Equation (27)

SEGH, SEGP, S in the above equations
EGR and SEGW represent heave mode gain, pitch mode gain, roll mode gain, and warp mode gain, and their values are fixed.

In step S510, based on the displacement mode gain obtained in step S508, the displacement mode inverse conversion is calculated for each wheel according to the following equation, and then the process proceeds to step S512 shown in FIG.

SB1 = EHS-EPS + ERS + EWS Formula (28) SB2 = EHS-EPS-ERS-EWS Formula (29) SB3 = EHS + EPS + ERS-EWS Formula (30) SB4 = EHS + EPS-ERS + EWS Formula (31)

In step S512 of FIG. 20, the proportional term gain of the displacement corresponding to the vehicle height value for the front and rear wheels is used to calculate the displacement proportional term for each of the front and rear wheels, and then the process proceeds to step S514.

CSP1 = SB1.Kzpf ... Equation (32) CSP2 = SB2.Kzpf ... Equation (33) CSP3 = SB3.Kzpr ... Equation (34) CSP4 = SB4.Kzpr ... Equation (35)

The proportional term gain Kzpf in each of the above equations,
Kzpr is the gain calculated in steps S436 and 440 when the damping force control is impaired in step S402 of FIG. 13, and is calculated in steps S450 and 452 when the control is not impaired. It is a gain.
That is, in the calculation of the displacement proportional term according to each of the above formulas, the proportional term gains Kzpf and Kzpr calculated according to whether or not the damping force control is disturbed are used properly.

In step S514, the displacement differential term for each of the front and rear wheels is calculated according to the following equation from the variation of the displacement mode inverse conversion calculation value and the differential term gain of the displacement corresponding to the vehicle height value for the front and rear wheels. After that, the process proceeds to step S516.

CSD1 = {SB1 (n) -SB1 (n-n1)} Kzdf ... Equation (36) CSD2 = {SB2 (n) -SB2 (n-n1)} Kzdf ... Equation (37) CSD3 = { SB3 (n) -SB3 (n-n1)} Kzdr ... Equation (38) CSD4 = {SB4 (n) -SB4 (n-n1)} Kzdr ... Equation (39)

Differential term gain Kzdf in each of the above equations,
Even in the case of Kzdr, as in the case of the proportional term gains Kzpf and Kzpr, the proper use is made depending on whether or not the damping force control is disturbed.
Note that SBi (n) in the above equations is the displacement mode inverse conversion calculation value calculated in step S510 in the present routine, and SBi (n-n1) is the displacement before n1 cycles (for example, one cycle before). It is a mode inverse conversion calculation value.

In step S516, the displacement integral term for each of the front and rear wheels is calculated according to the following mathematical expression, and then the process proceeds to step S518.

CSI1 = CSI1 + SB1.Kzif ... Equation (40) CSI2 = CSI2 + SB2.Kzif ... Equation (41) CSI3 = CSI3 + SB3.Kzir ... Equation (42) CSI4 = CSI4 + SB4.Kzir ... Equation (43)

Integral term gain Kzif in each of the above equations,
Even in the case of Kzir, as in the case of the proportional term gain and the differential term gain described above, the Kzir is properly used depending on whether or not the damping force control is disturbed.

In step S518, the displacement term total control amount for each of the front and rear wheels is calculated from the respective calculated values calculated in steps S512, 514, and 516, and then the process proceeds to step S520.

PX1 = CSP1 + CSD1 + CSI1 Equation (44) PX2 = CSP2 + CSD2 + CSI2 Equation (45) PX3 = CSP3 + CSD3 + CSI3 Equation (46) PX4 = CSP4 + CSD4 + CSI4 Equation

In the following step S520, the target pressures Pgx and Pgy are calculated based on the maps corresponding to the graphs shown in FIGS. 23 and 24 for the front-rear direction and the lateral direction of the vehicle, respectively, and then to step S522. move on.

In step S522, the PD compensation calculation of the horizontal G feedforward control is performed for the pitches (Cgpf, Cgpr) and rolls (Cgrf, Cgrr) relating to the front and rear wheels according to the following equations, and then, as shown in FIG.
1 proceeds to step S524 shown in FIG.

Cgpf = Kpgpf.Pgx + Kdgpf. {Pgx (n) -Pgx (n-n1)} Equation (48) Cgpr = Kpgpr.Pgx + Kdgpr. {Pgx (n) -Pgx (n-n1)} Equation (49) ) Cgrf = Kpgrf.Pgy + Kdgrf. {Pgy (n) -Pgy (n-n1)} Equation (50) Cgrr = Kpgrr.Pgy + Kdgrr. {Pgy (n) -Pgy (n-n1)} Equation (51)

Kpgpf, Kpgrf in the above equations
Is the proportional term gain of the horizontal acceleration of the front wheels with respect to roll and pitch, as described above, and Kpgpr,
Kpgrr is also a proportional term gain of horizontal acceleration for the rear wheel. Kdgpf and Kdgrf are horizontal acceleration differential term gains for the front wheel with respect to roll and pitch, and Kdgpr and Kdgrr are horizontal acceleration differential term gains for the rear wheel. Then, each of these gains is selectively used according to whether or not there is a hindrance to the damping force control, like the proportional term gain, differential term gain and integral term gain of the vehicle height value corresponding displacement. In the above equations, Pgx (n)
And Pgy (n) are the current Pgx and Pgy, respectively, and Pgx (n-n1) and Pgy (n-n1) are the Pgx and Pgy before n1 cycles, respectively.

In step S524 shown in FIG. 21, the inverse G-mode inverse transform is calculated according to the following equation, and then the process proceeds to step S526.

Pg1 = Kg1 / 4 · (−Cgpf + K2f · Cgrf + K1f · Gypr) Equation (52) Pg2 = Kg2 / 4 · (−Cgpf−K2f · Cgrf−K1f · Gypr) Equation (53) Pg3 = Kg3 /4.(Cgpr+K2r.Cgrr+K1r.Gypr) Equation (54) Pg4 = Kg4 / 4. (Cgpr-K2r.Cgrr-K1r.Gypr) Equation (55)

Kg1, Kg2, Kg3 in each of the above equations,
Kg4 is a proportional constant, K1f and K1r, K2f
And K2r are roll rigidity distribution gains between the front and rear wheels, as described above. Then, this roll rigidity distribution gain K
1f, K1r, K2f, and K2r are used properly depending on whether or not there is a problem in damping force control, like the above-described various gains for vehicle height value-related displacement and horizontal acceleration. Note that Gypr in each of the above equations is a change rate of the estimated lateral acceleration calculated from the steering angular velocity calculated as the time differential value of the steering angle θf and the vehicle speed V, and the steering angular velocity and the vehicle speed V correspond to this estimated lateral acceleration. It is calculated from the attached map.

In step S526, the vertical accelerations Gza and G detected by the vertical G sensors 140 to 144 are detected.
Based on zb and Gzc, the vertical accelerations Gz1 to Gz4 of the parts corresponding to the respective wheels are calculated according to the following formulas, and then the process proceeds to step S528.

Gz1 = Gza Equation (56) Gz2 = Gza-Gzb + Gzc Equation (57) Gz3 = Gzb Equation (58) Gz4 = Gzc Equation (59)

In step S528, the vertical accelerations Gz1 to Gz4 are integrated to calculate integrated values Iz1 to Iz4.
In subsequent step S530, the proportional term gains Kzpf and Kzpr of the displacements corresponding to the vehicle height values of the front and rear wheels are obtained.
, The proportional term of vertical acceleration Czp1 ~
Czp4 is calculated, and then the process proceeds to step S532.

Czp1 = Kzpf * Gz1 ... Equation (60) Czp2 = Kzpf * Gz2 ... Equation (61) Czp3 = Kzpr * Gz3 ... Equation (62) Czp4 = Kzpr * Gz4 ... Equation (63)

The proportional term gain Kzp in each of the above equations
Even f and Kzpr are used properly depending on whether or not there is a problem in damping force control.

In step S532, step S
Each integrated value Iz1 to I of the vertical acceleration of the vehicle body calculated in 528
Based on z4 and the integral term gains Kzif and Kzir on the front and rear wheels, the integral term of vertical acceleration, that is, the sprung speed terms Czi1 to Czi4, is calculated according to the following mathematical formula. Then, step S
Proceed to 534.

Czi1 = Kzif · Iz1 Equation (64) Czi2 = Kzif · Iz2 Equation (65) Czi3 = Kzir · Iz3 Equation (66) Czi4 = Kzir · Iz4 Equation (67)

The integral term gain Kzi in each of the above equations
Even for f and Kzir, it can be used properly depending on whether or not there is a problem in damping force control.

In step S534, step S
Based on the proportional term Czpj (j = 1, 2, 3, 4) calculated in 530 and the integral term Czij calculated in step S532, the feedback control amount Pzj based on the vertical acceleration is calculated according to the following mathematical formula. Then, step S536
Go to.

Pzj = Czpj + Czij Equation (68) (j = 1, 2, 3, 4)

In step S536, the ROM
The displacement feedback control amount based on the standard pressure Pbj in the working fluid chamber of each actuator (the pressure in the working fluid chamber when the vehicle in the standard loading state is stopped) and the posture change calculated in step S518 stored in Pxj
And a feedforward control amount Pgj based on the horizontal acceleration and the lateral acceleration calculated in step S524,
Based on the feedback control amount Pzj based on the vertical acceleration calculated in step S534, the control target pressure Puj of each pressure control valve is calculated according to the following mathematical formula, and then the process proceeds to step S600 in FIG.

Puj = Pbj + Pxj + Pgj + Pzj Equation (69) (j = 1, 2, 3, 4)

Then, in step S600, the control signal corresponding to the control target pressure Puj is changed to the pressure control valve 22F.
It is output to the drive circuits 132 to 138 corresponding to L to 22RR. Also, FIG. 7, FIG. 10, FIG. 11 or FIG.
3, the control signal corresponding to the damping force control amount (final target damping force control amount MCFINAL) calculated in FIG. 14 is also output to the drive circuits 150 to 156 corresponding to the variable aperture actuators 45FL to 45RR.

The fluid pressure type active suspension 10 of this embodiment described above has the following advantages.

(1) In the fluid pressure type active suspension 10 of the present embodiment, when the damping force control for the front and rear wheels is not hindered (step S442), the vehicle speed V and the steering angle θ are set.
Steps S200, 2 based on the driving operation of the passenger such as f
Various active control gains are increased / decreased and corrected according to the final target damping force control amount MCFINAL or the current damping force CT for securing the steering stability obtained in step 50 (step S444).
~ 452). Therefore, the final target damping force control amount MCFINA
When the target damping force or the current damping force CT of the actuator 36 due to L is increased to increase the responsiveness of the actuator 36 and the generated force, the control target pressure Puj of the pressure control valve 22 is adjusted by reducing the active control gain. Reduce. Therefore, in this case, the actuator 36
The oil supply to the control valve via the pressure control valve 22 is suppressed, and excessive control due to the increased responsiveness and generated force of the actuator 36 is mitigated. On the other hand, when the target damping force or the current damping force CT of the actuator 36 decreases and the responsiveness of the actuator 36 and the generated force decrease, the control target pressure of the pressure control valve 22 is increased through the correction of increasing the active control gain. Increase Puj. Therefore, the oil supply to the actuator 36 via the pressure control valve 22 is promoted, and the control delay due to the decrease in the responsiveness of the actuator 36 and the generated force is improved.

That is, in the fluid pressure type active suspension 10 of the embodiment, when the responsiveness of the actuator 36 and the generated force change with the change of the damping force,
In anticipation of the change, the control target pressure Puj of the pressure control valve 22
To increase or decrease. Therefore, according to the fluid pressure type active suspension 10 of the embodiment, the control characteristic of the sprung mass behavior is improved by alleviating or improving the excessive control or the control delay caused by the change in the response of the actuator 36 and the generated force. It is possible to alleviate the discomfort of the passengers.

(2) In the fluid pressure type active suspension 10 of this embodiment, the oil supply status from the pump 18 is detected by the E / G speed sensor 72 and the pressure sensor 70 (engine speed N, system pressure PS). ) Is monitored (step S150), and if a decrease in the oil supply is seen from this detection signal, the final target damping force control amount MCFINA
The lower limit damping force guard value CGARD / LOW for obtaining L is increased (step S252, FIG. 8, FIG. 9). If the target damping force control amount CSO once determined from the viewpoint of steering stability in step S200 based on the vehicle speed V, the steering angle θf, and other driving operations of the occupant is below the lower limit damping force guard value CGARD / LOW, this target The lower limit damping force guard value CGARD / LOW is used as the final target damping force control amount MCFINAL instead of the damping force control amount CSO (step S258).

That is, when a decrease in oil supply is observed, the fluid pressure type active suspension 10 limits the lower limit of the target damping force control amount CSO to set the final target damping force control amount MC.
FINAL is determined, and the damping force generated by the actuator 36 is set to a large value according to the situation of oil supply drop. Therefore, even if the supporting load that increases or decreases the actuator 36 is insufficient due to the decrease in the supply of oil from the pump 18, it is possible to secure the suppressing force against the posture change of the vehicle body caused by the driving operation of the occupant by increasing the damping force. . As a result,
According to the fluid pressure type active suspension 10, it is possible to reduce the occupant's discomfort by improving the control characteristics of sprung mass behavior.

Further, although the range of increase / decrease of the supporting load by the actuator 36 is limited under the condition of the decrease of the oil supply, the responsiveness of the actuator 36 is improved by increasing the damping force. Therefore, according to the fluid pressure type active suspension 10, it is possible to suppress the posture change with a relatively small increase in the supporting load even in the situation where the oil supply is reduced.

(3) In the fluid pressure type active suspension 10 of this embodiment, it is determined from the pressure sensor 70 whether or not the active suspension control for supplying / discharging the hydraulic oil to / from the actuator 36 via the pressure control valve 22 is hindered. The determination is made based on the transition of the detection signal (system pressure PS) (step S270). If the control is hindered, the shutoff valve 46 upstream of the actuator 36 is closed, and the active control is not performed thereafter. Moreover, the active control is not simply stopped, but steps S310 and S3 are performed.
Step S332 to Step S, which is the detailed processing of 20.
As indicated by 384, the target damping force control amount CNO is calculated according to the vertical acceleration due to the input from the road surface, and the damping force generated by the actuator 36 is damped to suppress the vertical vibration of the vehicle body and ensure the riding comfort. Increase to change to force.

As a result, according to the fluid pressure type active suspension 10, it is possible to enhance the damping property for the vertical vibration of the vehicle body by increasing the damping force generated by the actuator 36 and to secure the damping force for this vibration. Therefore, it is possible to reduce the occupant's discomfort by improving the control characteristics of sprung mass behavior.

(4) In the fluid pressure type active suspension 10 of this embodiment, the actuator 3 is constructed by adjusting the throttle opening of the variable throttle 44 via the variable throttle actuator 45.
It is determined from the output result of the potentiometer 74 whether or not there is a problem in the damping force changing control of 6 (step S40).
2). Then, if there is a problem in the control, step S4
As shown in 04 to step S440, depending on the degree of the obstacle, specifically, the damping force deviation between the final target damping force control amount MCFINAL in step S250 and the current damping force CT at the time of the control obstacle. Various active control gains are increased / decreased and corrected (steps S436 and 440).

Therefore, if the damping force of the actuator 36 cannot be changed to a desired damping force and the current damping force CT remains large (damping force deviation <0), the pressure control valve 22 is corrected through the correction correction of the active control gain. The control target pressure Puj is reduced. Therefore, in this case, the oil supply to the actuator 36 via the pressure control valve 22 is suppressed and the responsiveness of the actuator 36 is generated in the situation where the damping force CT is large and the responsiveness of the actuator 36 is enhanced. Power is reserved. On the other hand, if the damping force of the actuator 36 cannot be changed to the desired damping force and the current damping force CT remains small (damping force deviation> 0), the control target pressure of the pressure control valve 22 is increased through the correction of increasing the active control gain. Increase Puj. Therefore, in this case, when the current damping force CT is small and the responsiveness of the actuator 36 is low, the responsiveness of the actuator 36 and the generated force are enhanced by promoting the oil supply.

As a result, according to the fluid pressure type active suspension 10, when an excess or deficiency of the damping force occurs as a mode in which the damping force is not effectively changed, the damping force and the posture change suppressing force due to the excess or deficiency are generated. It is possible to make up for the decrease in the load by increasing or decreasing the supporting load, so that the occupant's discomfort can be alleviated by improving the control characteristics of the sprung mass behavior.

The fluid pressure type active suspension 10 of this embodiment has the following advantages.

In the fluid pressure type active suspension 10, if the damping force changing control of the actuator 36 is hindered, in addition to the increase / decrease control of the active control amount (control target pressure Puj) through the above-mentioned increase / decrease correction of the active control gain. The damping force is also changed and controlled as follows. In other words, when the damping force change control is impaired only on one of the front wheels or one of the rear wheels, the damping force of the other wheel that does not interfere with the control is hampered by the control of the other wheel. Match or approximate the damping force of the wheel. For this reason, since the damping forces in the left and right wheels of the front wheels and the rear wheels are not imbalanced, the occupant does not feel uncomfortable.

Although one embodiment of the present invention has been described above, the present invention is not limited to such an embodiment and can be implemented in various modes without departing from the gist of the present invention. Of course.

For example, in the fluid pressure type active suspension 10 in the above-described embodiment, a series of corrections for increasing / decreasing the active control amount of the actuator 36 according to the damping force for ensuring the steering stability determined based on the driving operation of the occupant. The process, a series of processes for increasing and correcting the damping force because the active control by the actuator 36 becomes insufficient when the decrease in the supply of oil is observed, and the damping force generated by the actuator 36 when the active suspension control is hindered. If the damping force change control of the actuator 36 is impaired, the active control amount is increased / decreased according to the degree of the obstruction when the damping force change control of the actuator 36 is impaired by suppressing the vertical vibration of the vehicle body and increasing the damping force. Although a configuration in which a series of processes for correction is used together is adopted, the present invention is not limited to this. That is, a fluid pressure type active suspension of a configuration that performs each of the above series of processing independently,
It is also possible to provide a fluid pressure type active suspension having a configuration in which the series of processes described above are performed in an arbitrary combination.

Furthermore, the active calculation, that is, the calculation of the control target pressure Puj in the working fluid chamber 38 of each actuator 36 is performed in a specific manner based on the detection results of various sensors and various gains. The mode of calculation of the target pressure Puj is to control the target pressure in the working fluid chamber 38 of each actuator 36 according to the running state of the vehicle, thereby favorably controlling the vehicle height of the vehicle body, its posture, and the riding comfort of the vehicle. Any mode can be adopted as long as the calculation is possible.

Further, in the present embodiment, the control valve is constructed as the pressure control valve 22 which directly introduces the pressure in the connection passage 32 and the branch passage 26 to perform switching, but this control valve is provided in the working fluid chamber 38. Needless to say, it may be configured as a flow rate control valve in which the pressure is detected by a pressure sensor and is electrically switched by a solenoid or the like based on the detected value.

Further, in this embodiment, when a decrease in the oil supply is observed, the active control by the actuator 36 becomes insufficient, and a series of processes for increasing and correcting the damping force are limited to the lower limit of the target damping force control amount CSO. However, it can be configured as follows. That is, the target damping force control amount CSO for securing the steering stability based on the driving operation of the occupant such as the vehicle speed V and the steering angle θf is directly calculated in accordance with the decrease in the oil supply in the calculation process. You can also More specifically, step S20
The predetermined values α 1 and α in FIGS. 4 to 6 used for the calculation at 0
As shown in FIG. 25, 2 and α3 are reduced if the engine speed is low, and the inclination in FIGS. 4 to 6, that is, the rate of change (increasing rate) of the damping force is as shown in FIG. If the engine speed is low, increase it. With this configuration, when the engine speed is low and the oil supply is low, the target damping force control amount CSO is directly calculated by increasing the damping force control amount.

Further, the actuator 3 is responsive to the damping force for ensuring the steering stability determined based on the driving operation of the occupant.
In performing a series of processing for increasing / decreasing the active control amount of 6, the gain is increased / decreased by ΔK while comparing the target gain mK corresponding to the damping force or the control amount with the current gain KLIVE of each active control gain. Configured,
It can also be configured as follows. That is, it is also possible to directly calculate by map interpolation from the map corresponding to the graph shown in FIG. 27 and the damping force or its control amount. Further, instead of the increase / decrease correction of the active control gain, the following configuration can be adopted. That is, step S536
Subsequent to, a process for processing the control target pressure Puj to the low-pass filter process is added, and the cutoff frequency at that time is
As shown in FIG. 28, it may be configured to be variable according to the damping force or the damping force control amount. This low-pass filter process can be realized by, for example, the following mathematical expression, and by performing the process, the control target pressure Puj is increased or decreased according to the damping force.

LPuj = LPuj + (Puj−LPuj) · KLPF / P Equation (70) (j = 1, 2, 3, 4)

LPuj in the above equation is the control target pressure obtained by the filter processing, and KLPF / P
Is the filter constant.

[0174]

As described above in detail, in the suspension control device according to the first aspect, if the damping force is changed, the responsiveness of the actuator and the generated force change in level, but in consideration of the change in level. The control amount of the feeding / discharging means is increased and corrected. Therefore, according to the suspension control device of the first aspect, the control characteristic of the sprung mass behavior is improved by alleviating or improving the excessive control or the control delay caused by the change in the response of the actuator and the generated force. Therefore, the occupant's discomfort can be reduced.

In the suspension control device according to the second aspect, when a decrease in the supply of the working fluid is observed and a decrease in the responsiveness of the actuator and a decrease in the generated force are expected, the damping force generated by the actuator is adjusted to the decrease in the supply. Increase to increase depending on the situation. As a result, claim 2
According to the suspension control device described above, it is possible to secure a suppression force against a posture change by increasing the damping force, improve the control characteristics of sprung mass behavior, and reduce the occupant's discomfort. Further, according to the suspension control device of the present invention, the range of increase and decrease of the force generated by the actuator is limited under the condition of the supply of the working fluid being reduced, but the responsiveness of the actuator is increased by increasing the damping force. Therefore, the sprung mass can be controlled with a relatively small increase in the generated force.

In the suspension control device according to the third aspect of the present invention, when the effect of controlling the supply / discharge of the working fluid to / from the actuator becomes inadequate and the desired support load increase / decrease by the actuator cannot be obtained, the damping force generated by the actuator is reduced. It is increased to the side where the damping property against sprung vibration appearing on the spring in response to the input is increased. As a result, according to the suspension control device of the third aspect, it is possible to improve the damping property against the sprung vibration by increasing the damping force generated by the actuator and secure the damping force against the sprung vibration. Therefore, the occupant's discomfort can be alleviated by improving the control characteristics of sprung mass behavior. Also,
According to the suspension control device of the third aspect, the control for enhancing the vibration damping property by changing the increase of the damping force is executed for the first time when the supply / discharge control of the working fluid is not effective. Can be performed without being adversely affected by the supply / discharge control of the working fluid, and its effectiveness can be enhanced.

According to the suspension control device of the fourth aspect, even if the damping force generated by the actuator is not changed effectively and the desired damping force cannot be obtained, the suspension control device changes according to the changing state of the damping force at that time. Through the supply / discharge control of the working fluid, the responsiveness of the actuator and the generated force are increased / decreased. As a result, according to the suspension control device of the fourth aspect, it is possible to supplement the damping force and the restraint force of the posture change due to the inappropriate change of the damping force by the supply / discharge control of the working fluid. The occupant's discomfort can be alleviated by improving the control characteristics of sprung mass behavior.

In the suspension control device according to the fifth aspect, the supply / discharge control of the working fluid to / from the actuator and the change control of the damping force generated by the actuator are harmonized to the side where the effectiveness of both the controls can be harmonized. Let it be related. That is, the excess or deficiency of the support load increase or decrease of the actuator or the excess or deficiency of the damping force, which occurs due to the ineffectiveness of the control of either of these controls, is compensated by increasing the effectiveness of the other control. As a result, according to the suspension control device of the fifth aspect, the supply / discharge control of the working fluid and the change control for changing the damping force can be complemented in terms of their effectiveness, so that the control characteristic of the sprung behavior is improved. It is possible to reduce the discomfort of the passengers by improving

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a fluid pressure type active suspension 10 which is one embodiment of a suspension control device according to the present invention.

2 is a block diagram showing an electronic controller for controlling the pilot pressure controller and the pressure control valve shown in FIG. 1. FIG.

FIG. 3 is a general flow chart showing a suspension control flow achieved by the electronic control device shown in FIG.

FIG. 4 is step S2 of the flowchart shown in FIG.
10 is a graph for explaining the content of the processing for calculating the target damping force control amount performed at 00, where the vehicle speed V and the steering angle θ are
6 is a graph showing the relationship between the multiplication value of f and the number of damping force steps.

FIG. 5 is a graph for explaining the content of the target damping force control amount calculation processing similarly performed in step S200, and is a graph showing the relationship between the vehicle height front-back difference and the damping force step number.

FIG. 6 is a graph for explaining the details of the processing of the target damping force control amount CSO calculation that is similarly performed in step S200, and is a graph showing the relationship between the throttle opening speed and the number of damping force steps.

7 is a step S2 of the flowchart shown in FIG.
5 is a flowchart showing detailed processing of a target damping force control amount correction calculation performed in 50.

FIG. 8 is a step S2 of the flowchart shown in FIG.
It is a graph for demonstrating the content of the process of 52, and is a graph which shows the relationship between engine speed N and lower limit damping force guard value CGARD / LOW.

FIG. 9 is a step S2 of the flowchart shown in FIG.
It is a graph for demonstrating the content of the process of 52, and is a graph which shows the relationship between system pressure PS and lower limit damping force guard value CGARD / LOW.

10 is a step S of the flowchart shown in FIG.
It is a flow chart which shows the first half part of detailed processings, such as calculation of target damping force control quantity CNO performed in 310 to step S330.

FIG. 11 is a flowchart showing the latter half of the process.

FIG. 12 is a target damping force control amount CNO shown in FIGS.
It is explanatory drawing explaining the relationship between damping force calculation flag fNO in calculation, and target damping force control amount CNO.

FIG. 13 is a step S of the flowchart shown in FIG.
6 is a flowchart showing a first half portion of detailed processing of active control gain calculation performed in 400.

FIG. 14 is a flowchart showing the latter half of the process.

FIG. 15 is a step S4 of the flowchart shown in FIG.
36 is a graph for explaining the content of the gain calculation process performed in 36, where the damping force deviation and the correction coefficient Kihh
It is a graph which shows the relationship with.

FIG. 16 is a graph for explaining the details of the gain calculation process performed in step S436, showing the relationship between the damping force deviation and the correction coefficient Kh.

FIG. 17 is a step S4 of the flowchart shown in FIG.
6 is a graph for explaining the content of the gain calculation process performed in 40, in which the damping force deviation and the correction coefficient Kifh are shown.
It is a graph which shows the relationship with.

FIG. 18 is a step S4 of the flowchart shown in FIG.
4 is a graph for explaining the contents of the gain calculation process performed in 44, and is a graph showing the relationship between the damping force or the damping force control amount and the target gain mK.

FIG. 19 is a step S of the flowchart shown in FIG.
6 is a flowchart showing a first half portion of an active calculation routine performed in 500.

FIG. 20 is a flowchart showing the middle part of this active calculation routine.

FIG. 21 is a flowchart showing the remaining part of the active calculation routine.

FIG. 22 is a step S5 of the flowchart shown in FIG. 19;
2 is a graph for explaining the content of the target displacement value Rxh calculation processing performed in 02, and is a graph showing the relationship between the vehicle speed V and the target displacement value Rxh.

FIG. 23 is a step S5 of the flowchart shown in FIG. 20;
20 is a graph for explaining the content of the process of calculating the target pressure Pgx performed in 20, and is a graph showing the relationship between the longitudinal acceleration Gx and the target pressure Pgx.

FIG. 24 is a graph for explaining the details of the target pressure Pgy calculation process, and is a graph showing the relationship between the lateral acceleration Gy and the target pressure Pgy.

FIG. 25 is a graph showing a relationship between predetermined values α1, α2, α3 used for calculation of the target damping force control amount CSO and the engine speed N in the modified example.

[Fig. 26] Fig. 4 to Fig. 4 used to calculate a target damping force control amount CSO
7 is a graph showing the relationship between the inclination of FIG. 6 and the engine speed N.

FIG. 27 is a graph used when calculating an active control gain by map interpolation in a modified example, and is a graph showing a relationship between various gains and a damping force or a damping force control amount.

FIG. 28 is a cut-off frequency KLPF / P when the control target pressure Puj is processed by a low-pass filter in the modification.
It is a graph which shows the relationship between damping force or damping force control amount.

[Explanation of symbols]

 10 ... Fluid pressure type active suspension 11 ... Reservoir 12 ... Connection passage 14 ... Working fluid discharge passage 14a ... Communication connection portion 15 ... Check valve 16 ... Engine 18 ... Pump 20 ... Working fluid supply passage 22 ... Pressure control valve 24 ... Switching control Valve 26 ... Branch passage 28 ... Fixed throttle 30 ... Variable throttle 32 ... Connection passage 35 ... Suspension member 36 ... Actuator 38 ... Working fluid chamber 40 ... Passage 42 ... Gas-liquid spring device 44 ... Variable throttle 45 ... Variable throttle actuator 46 ... Shut off Valve 48 ... Pilot pressure control device 50 ... Connection passage 52 ... Fixed throttle 54 ... Variable throttle 60 ... Accumulator 62 ... Piston 64 ... Hydraulic oil flow hole 70 ... Pressure sensor 72 ... E / G rotation speed sensor 74 ... Potentiometer 100 ... Electronic control Device 102 ... Microcomputer 116 ... Ig Option switch 118 ... vehicle height sensor 120 ... vehicle speed sensor 122 ... longitudinal G sensor 124 ... lateral G sensor 126 ... steering angle sensor 128 ... vehicle height setting switch 140, 142, 144 ... vertical G sensor 146 ... yaw rate sensor 148 ... brake sensor Wh ... Wheel mCNO ... Virtual target damping force mK ... Target gain

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiaki Hamada 2-1, Asahi-machi, Kariya city, Aichi Aisin Seiki Co., Ltd. (72) Shinichi Tagawa 2-chome, Asahi-cho, Kariya city, Aichi Aisin Seiki Incorporated (72) Inventor Hideyuki Kobayashi 2-1-1 Asahi-cho, Kariya City, Aichi Prefecture Aisin Seiki Co., Ltd. (72) Inventor Kenji Hayashi 2--1 Asahi-cho, Kariya City, Aichi Prefecture Aisin Seiki Co., Ltd.

Claims (5)

[Claims] 1. An actuator interposed between a sprung member and an unsprung member of a vehicle for increasing or decreasing a supporting load of a corresponding unsprung member by supplying and discharging a working fluid, and a working fluid from a working fluid supply source. A supply / discharge means for supplying / discharging a working fluid to / from the actuator, a damping force changing means for changing a damping force generated by the actuator; a running state detecting means for detecting a running state of the vehicle; A supply / discharge control means for controlling the supply / discharge means with a control amount according to the detected traveling state, and performing a sprung mass behavior control according to the traveling state of the vehicle via the actuator, and the supply / discharge control means for controlling the supply / discharge. A suspension control device comprising: a control amount correcting unit that corrects the control amount when controlling the ejecting unit according to the magnitude of the damping force by the damping force changing unit. 2. An actuator, which is interposed between a sprung member and an unsprung member of a vehicle, for increasing / decreasing a supporting load of a corresponding unsprung member by supplying / discharging working fluid, and a working fluid supply source A supply / discharge means for supplying / discharging a working fluid to / from the actuator, a damping force changing means for changing a damping force generated by the actuator; a running state detecting means for detecting a running state of the vehicle; A supply / discharge control means for controlling the supply / discharge means by a control amount according to the detected traveling state, and performing sprung mass behavior control according to the traveling state of the vehicle through the actuator, and an operation from the working fluid supply source. A working fluid supply monitoring means for monitoring the supply status of the fluid, and a decrease in the supply of the working fluid is observed from the monitored supply status of the working fluid, the damping force increases if the supply of the working fluid decreases. The suspension control device further comprises a damping force change control means for controlling the damping force change means according to a supply state of the working fluid. 3. An actuator, which is interposed between a sprung member and an unsprung member of a vehicle, for increasing / decreasing a supporting load of the corresponding unsprung member by supplying / discharging the working fluid, and a working fluid from a working fluid supply source. A supply / discharge means for supplying / discharging a working fluid to / from the actuator, a damping force changing means for changing a damping force generated by the actuator; a running state detecting means for detecting a running state of the vehicle; A supply / discharge control means for controlling the supply / discharge means by a control amount according to the detected traveling state and performing sprung mass behavior control according to the traveling state of the vehicle through the actuator, and a supply of a working fluid to the actuator. A supply / discharge suitability determining means for determining the effective suitability of the discharge control, and a spring developed on the spring according to the road surface input when the supply / discharge suitability determining means determines the effective suitability of the supply / discharge control of the working fluid. A suspension control device comprising: a damping force change control unit that controls the damping force change unit according to the road surface input, on the side where the damping property against upper vibration is increased. 4. An actuator, which is interposed between a sprung member and an unsprung member of a vehicle, for increasing / decreasing a supporting load of a corresponding unsprung member by supplying / discharging a working fluid, and a working fluid supply source A supply / discharge means for supplying / discharging a working fluid to / from the actuator, a damping force changing means for changing a damping force generated by the actuator; a running state detecting means for detecting a running state of the vehicle; A supply / discharge control means for controlling the supply / discharge means by a control amount according to the detected traveling state and performing sprung mass behavior control according to the traveling state of the vehicle through the actuator, and a damping force by the damping force changing means. Damping force change state monitoring means for monitoring the changing state of the damping force, damping force change appropriateness determination means for determining whether the damping force change means effectively changes the damping force, and damping force change appropriateness determination means When it is determined that the damping force change is not effective, the control amount when the supply / discharge control unit controls the supply / discharge unit is corrected according to the damping force change state monitored by the damping force change state monitoring unit. And a control amount correcting means for controlling the suspension amount. 5. An actuator which is interposed between an unsprung member and an unsprung member of a vehicle and which increases or decreases the supporting load of the corresponding unsprung member by supplying and discharging the working fluid, and a working fluid supply source A supply / discharge means for supplying / discharging a working fluid to / from the actuator, a damping force changing means for changing a damping force generated by the actuator; a running state detecting means for detecting a running state of the vehicle; Supply / discharge control means for controlling the supply / discharge means in accordance with the detected running state and for controlling the sprung mass behavior according to the running state of the vehicle via the actuator; and supply / discharge control status of working fluid to the actuator Based on the changing situation of the damping force by the damping force changing means,
A harmony means for harmonically controlling the supply / discharge control means and the damping force changing means is provided on the side where the effectiveness of the supply / discharge control and the effectiveness of changing the damping force can be harmonized. Suspension control device.