Abstract: An apparatus for controlling a damping force of a shock absorber provided between a wheel of a vehicle and a body thereof includes a road surface condition detecting unit for detecting a roughness of a road surface on which the vehicle is traveling, and a damping force characteristic alteration unit for altering the setting of the damping force of the shock absorber on the basis of the roughness of the road surface detected by the road surface condition detecting unit. The apparatus also includes a damping force detecting unit, for detecting a magnitude of the damping force of the shock absorber, and an alteration speed control unit for controlling, on the basis of the magnitude of the damping force detected by the damping force detecting unit, an alteration speed at which the setting of the damping force is altered so that the alteration speed decreases as the magnitude of the damping force increases.

Abstract: A suspension control system controls suspensions provided for wheels of a vehicle includes a driving condition detecting part for detecting a driving condition of the vehicle, and a determination part for determining whether or not the driving condition detected by the driving condition detecting part coincides with a predetermined driving condition. The suspensions are grouped into a plurality of groups. Also the system includes a control part for separately controlling the suspensions on the basis of the driving condition when the determination part determines that the driving condition does not coincide with the predetermined driving condition and for controlling the suspensions for each of the groups so that the suspensions in an identical group are set to an identical condition when the determination part determines that the driving condition coincides with the predetermined driving condition.

Abstract: A drive system of a piezo-type actuator for use in a motor vehicle, which piezo-type actuator is constructed with a piezoelectric device which is expandable and contractible in accordance with application of a voltage thereto. The drive system includes a voltage-increasing section for increasing an output voltage of a power source mounted on the motor vehicle so as to develop a drive voltage for the piezo-type actuator and a voltage-application section for applying to the piezoelectric device of the piezo-type actuator the drive voltage. Also included in the drive system is an abnormality detection section which is arranged so as to an abnormality of the drive voltage developed by the voltage-increasing section.