Abstract: A vehicle axle suspension system including wheel support members for rotatably supporting road wheels, a suspension member for supporting the road wheel support members for vertical swinging movement, and elastic suspension elements. The elastic suspension elements include a pair of front elastic suspension elements provided at different suspension points in front of the road wheel support members for elastically mounting the suspension member to the vehicle and a pair of rear elastic suspension elements provided at different suspension points behind the road wheel support members for elastically mounting the suspension member to the vehicle. The elastic suspension elements are positioned to provide an understeer characteristic when a lateral force acts on a suspension roll center determined by suspension geometry to rotate the suspension member around a virtual roll axis extending through an elastic center of the front elastic suspension elements and an elastic center of the rear elastic suspension elements.

Abstract: An active suspension system is provided which includes hydraulic cylinders for suppressing rolling motion of a vehicle body. The system is responsive to lateral acceleration acting on the vehicle body to provide a control signal for supplying hydraulic pressure to the cylinders for anti-rolling control. The control signal includes first and second pressure control signals. The first pressure control signal commands supply of hydraulic pressure for providing an anti-rolling moment, while the second pressure control signal commands supply of hydraulic pressure for supporting a portion of the static load of the vehicle body to maintain the vehicle body at a target height level.

Abstract: An actively controlled suspension system includes a vehicular rolling detecting component to adjust the suspension characteristics for suppressing the vehicular rolling. In addition, the actively controlled suspension control system may be provided for adjusting roll-stabilization load distribution between the front and rear suspension systems for adjusting vehicular driving stability by suppressing rolling and pitching of the vehicle body.

Abstract: An anti-rolling suspension control system generally derives anti-rolling control signals for controlling suspension characteristics of respective suspension systems in order to suppress vehicular rolling motion. The system is further provided means for monitoring road friction condition. The system derives distribution of rolling moment distribution ratio between front suspension systems and rear suspension systems based on the monitored road friction condition so that the derived distribution may be adapted to the road surface frictional condition.

Abstract: A suspension control system employs a first lateral acceleration sensor for monitoring a lateral acceleration at a first point on a vehicular body and a second lateral acceleration sensor for monitoring lateral acceleration at a second point on the vehicular body, which second point is provided at a longitudinally offset position from the first point. A controller derives a lateral shifting of vehicular load at the front suspension systems on the basis of a first lateral acceleration monitored by the first lateral acceleration sensor, and a lateral shifting of the vehicular load at a rear suspension system on the basis of a second lateral acceleration monitored by the second lateral acceleration sensor. Control for front and rear suspension systems is performed independently on the basis of the lateral load shifting at the front and rear suspension systems.

Abstract: An actively controlled suspension system employs a pressure control valve which is operable in response to a control signal and controls fluid pressure in the fluid chamber of a hydraulic cylinder as a replacement for the conventional hydraulic shock absorber. The pressure control valve is associated with a controller which detects bounding and rebounding acceleration and stroke speed in bounding and rebounding motion for deriving a control signal to operate the pressure control valve to absorb vibration energy to be transmitted between a vehicle body and a suspension member.

Abstract: An active suspension system for an automotive vehicle is provided which regulates relative displacement between a vehicle body and wheels. This suspension system includes first and second gain controllers associated with hydraulic cylinders for supressing vehicular rolling based on lateral acceleration acting on the vehicle body. The first and second gain controllers amplify the level of the lateral acceleration, monitored by a sensor, by first and second gains respectively to vary pressure of the hydraulic cylinders. The suspension system further includes a low-pass filter which restricts a frequency of a signal output from the acceleration sensor high than a preselected cutoff frequency to decrease the second gain relative to the first gain to reduce the degree of load shift for the rear wheels relative to that of the front wheels.

Abstract: An actively controlled suspension system employs a lateral acceleration sensor for monitoring lateral acceleration exerted on the vehicular body. The lateral acceleration is shifted frontwardly from a gravity center of the vehicle body at the neutral position or non-rolling condition. The magnitude of frontward offset of the lateral acceleration sensor is so selected as to cancel influence of phase delay when the lateral acceleration sensor is oriented at the position of the neutral gravity sensor.

Abstract: A pressure supply network for an active suspension system employs a strategy for predicting consumed fluid flow rate on the basis of bounding and rebounding stroke between a vehicular body and a suspension member rotatably supporting a vehicular wheel. A discharge rate of a fluid pump disposed in the pressure supply network is controlled on the basis of the predicted fluid flow rate.

Abstract: A fluid supply system is provided for an active vehicle suspension system, for supplying fluid pressure for a hollow working cylinder via a pressure control valve for adjusting suspension characteristics of the vehicle in order to suppress vehicular attitude changes and to absorb road shock vibration, the system having a pressurized fluid source unit for circulating a pressurized fluid through a fluid circuit extending via the pressure control valve and the working cylinder. A first sensor is provided for monitoring a relative displacement between the body of the vehicle and a suspension member rotatably supporting a road wheel thereof, for producing a relative displacement magnitude indicative signal. A second sensor is provided for monitoring a lateral acceleration exerted on the vehicle body. A predicted fluid flow amount through said fluid circuit is derived on the basis of the relative displacement indicative signal to produce a predicted fluid flow amount indicative signal.

Abstract: An active suspension system utilizes an acceleration exerted on a vehicle body and a stroke magnitude in relative displacement between the vehicle body and a suspension member as parameters for controlling discharge rate of pressure medium fluid from a pressure source unit. The pressure source unit is normally driven at limited discharge rate for minimizing driving power consumption. The pressure source unit is responsive to the vertical acceleration greater than a predetermined acceleration criterion and to vertical stroke magnitude greater than a predetermined stroke criterion to increase discharge rate for compensating pressure medium fluid amount to be consumed for suspension control.

Abstract: An actively controlled suspension system has two hydraulic systems for generating damping force against the vibration to be transmitted between a vehicle body and a suspension member. One of the hydraulic systems is designed for absorbing relatively high frequency vibration generally input from the suspension member for preventing vibration from the suspension member from being transmitted to the vehicle body. The other hydraulic system is active on relatively low frequency of vibration generally input from the vehicle body upon change of attitude of the vehicle body. The other hydraulic system generates a fluid pressure suppressing the attitude change. A pressure control valve and a fluid pressure source may be incorporated in the second hydraulic system so that they may not be active when aforementioned one of the hydraulic system is active.

Abstract: A vehicular height regulation system performs attitude change suppressive suspension control for equalized magnitude at respective of front and rear wheels. For performing equalized magnitude not only for the front suspension systems, the vehicular height control system includes a pair of actuator means associated with respective of rear-left and rear-right wheels, which actuator means are operable independently of each of other.

Abstract: A slip angle monitoring system directly compares an absolute value of lateral acceleration with an experimentarily derived given value which serves as a slip criterion to determine slip angle of a vehicle. Slip angle is set at zero while the absolute value of the lateral acceleration is smaller than or equal to the given value. On the other hand, when the absolute value is greater than the given value, the slip angle is derived by dividing the lateral acceleration by the longitudinal acceleration or by taking the minus one power of the tangent of the quotient obtained by dividing the lateral acceleration by the longitudinal acceleration, that is, the cotangent of the quotient.

Abstract: An active suspension control system employs a strategy minimum fluid pressure in the working chamber of an inside suspension system is reached at greater lateral acceleration than that via which at which the maximum fluid pressure in the working chamber of an outside suspension system is reached. The system also takes a strategy for adjusting the fluid pressure in the working chambers of the inside and outside suspension system inversely proportional to each other while the lateral acceleration is maintained smaller than a predetermined pressure at which the maximum fluid pressure in the working chamber of the outside suspension system is reached. This assures driving stability and riding comfort by permitting vehicular rolling in response to a lateral acceleration greater that a given lateral acceleration criterion.

Abstract: An an actively controlled suspension system includes a fail-safe system which is associated with a pressure control valve and detective of failure of a control circuit to perform fail-safe operation. The fail-safe system operates the pressure control valve in response to failure of the control circuit, to fix the valve position corresponding to a working fluid pressure in a working chamber defined in a suspension cylinder disposed between a vehicular body and a suspension member rotatably supporting a vehicular wheel, at a pressure value at or in the vicinity of a predetermined initial or neutral pressure.

Abstract: A hydraulic circuit for an active suspension system employs a pressure accumulator connected to a drain line at an orientation upstream of a pilot operated operational one-way check valve. The pressure accumulator absorbs back pressure generated in the drain line due to flow resistance in the drain line.

Abstract: An actively controlled suspension system introduces two-way mode operation in controlling suspension. A suspension control system operates in a normal mode for controlling fluid pressure in a hydraulic cylinder disposed between a vehicle body and a suspension member is adjusted depending upon the vehicle driving conditions in order to suppress vehicular attitude change, and a power OFF transition mode for controlling the fluid pressure toward a preset neutral pressure. The hydraulic circuit is constructed to maintain the pressure in the working chamber of the hydraulic cylinder at the neutral pressure while power is not supplied to control system.

Abstract: An active suspension control system performs anti-rolling control in response to vehicular rolling by inducing counter rolling in a direction opposite to the vehicular body rolling direction. Magnitude of counter rolling is differentiated between front and rear suspension systems for providing desired steering characteristics. The steering characteristics is adjusted depending on the demand on stability factor in cornering.

Abstract: An actively controlled suspension system which can perform precise control of suspension characteristics with satisfactory compensation of phase delay caused in a control system. The actively controlled suspension system which can successfully avoid influence of the shifting of the gravity center of a vehicle body caused by a variation of load on the vehicle. The actively controlled suspension system employs more than one lateral acceleration sensor which are oriented at axially or longitudinally shifted positions to each other. Based on the outputs of respective lateral acceleration sensors, anti-rolling suspension control signals are produced for controlling suspension characteristics of the left- and right-sides of a suspension system.