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: 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.