Abstract: A damper with a controllable variable damping force, includes a piston and a cylinder provided with a magnetic viscous fluid and piston therein. An interior of the cylinder is divided by the piston into first and second fluid chambers which communicate with each other. A controller energizes a coil provided to the piston, wherein a viscosity of the magnetic viscous fluid in the fluid passage is changed when the coil is energized. When the controller fails to energize the coil, an electric current supply circuit supplies a predetermined constant electric current to the coil. Alternatively, when the controller detects an abnormality in energizing control of the coil, the controller supplies the predetermined constant electric current to the coil. Further, a sub-coil may be provided with the piston, wherein the controller supplies the sub-coil with a predetermined constant electric current whenever the coil is not operating properly.

Abstract: In a suspension control system, accelerations detected by acceleration sensors are differentiated by a differentiator to calculate acceleration derivative values. Based on these values, a target electrical current calculating section calculates a target electrical current that is supplied to an actuator which controls a damping force of a damper. Before a rolling or pitch angle occurs in the vehicle, the change of the rolling or pitch angle is predicted to control the damping force of the damper, thereby improving the response of rolling angle and pitch angle control to achieve, simultaneously, an accurate posture control and a satisfactory riding comfort. Because the target electrical current calculating section corrects the target electrical current of the actuator based on a damper speed obtained by differentiating a damper displacement, even when a large input is applied to the damper due to an unevenness of the road surface, a proper posture control is performed.

Abstract: In the present invention, when the controlling of the damping force of a damper by an actuator becomes impossible in a suspension apparatus for a vehicle, having an actuator for controlling the damping force of the damper for a suspension from which a wheel is suspended from a vehicle body, and a regulating device that regulates a vehicle height by extending and contracting the damper, the vehicle height regulation device extends and contracts the damper and thereby reduce the vehicle height. Therefore, even when the damper is fixed in a low damping force condition with the rolling rigidity and pitching rigidity of the vehicle in a lowered state, the stability of the vehicle can be secured by extending and contracting the damper by the actuator and thereby reducing the vehicle height and lowering the center of gravity of the vehicle.

Abstract: A damper with a controllable variable damping force, includes a piston and a cylinder provided with a magnetic viscous fluid and piston therein. An interior of the cylinder is divided by the piston into first and second fluid chambers which communicate with each other. A controller energizes a coil provided to the piston, wherein a viscosity of the magnetic viscous fluid in the fluid passage is changed when the coil is energized. When the controller fails to energize the coil, an electric current supply circuit supplies a predetermined constant electric current to the coil. Alternatively, when the controller detects an abnormality in energizing control of the coil, the controller supplies the predetermined constant electric current to the coil. Further, a sub-coil may be provided with the piston, wherein the controller supplies the sub-coil with a predetermined constant electric current whenever the coil is not operating properly.

Abstract: In a suspension control system, accelerations detected by acceleration sensors are differentiated by a differentiator to calculate acceleration derivative values. Based on these values, a target electrical current calculating section calculates a target electrical current that is supplied to an actuator which controls a damping force of a damper. Before a rolling or pitch angle occurs in the vehicle, the change of the rolling or pitch angle is predicted to control the damping force of the damper, thereby improving the response of rolling angle and pitch angle control to achieve, simultaneously, an accurate posture control and a satisfactory riding comfort. Because the target electrical current calculating section corrects the target electrical current of the actuator based on a damper speed obtained by differentiating a damper displacement, even when a large input is applied to the damper due to an unevenness of the road surface, a proper posture control is performed.

Abstract: In an active suspension system, an electromagnetic actuator is interposed between a tube connected to a vehicle body and a rod connected to a wheel. The electromagnetic actuator includes a motor vertically slidably accommodated within the tube and supported in a floating manner by motor supporting springs, and a ball screw driven by the motor. The displacement between the vehicle body and the wheel and the load are controlled by driving the ball screw by the motor. When a fierce load is applied from the wheel, the motor itself resiliently moves upwardly while compressing one of the motor supporting springs, thereby permitting the upward movement of the rod to prevent the locking of the active suspension system, leading to an enhanced riding comfort.