Abstract: A vibration/noise active control system for automotive vehicles which generates a canceling signal for canceling vibrations and noises generated within the compartment of the vehicle, based on a reference signal related to the vibrations and noises by means of an adaptive filter. The canceling signal is converted into a canceling sound. The adaptive filter has a filter coefficient thereof changed based on the cancellation error between the canceling sound and the vibrations and noises within the compartment, detected by an error sensor, and the reference signal. A memory stores a plurality of filter coefficient values of the adaptive filter corresponding to a plurality of predetermined traveling conditions of the vehicle.

Abstract: A hydraulic servomechanism comprises a basic body having an axial hole formed therein, a stationary element provided on the outer peripheral surface of the basic body at a predetermined location, a sliding element fitted on the outer peripheral surface of the basic body and also fitted with the stationary element for axial sliding movement relative thereto. The sliding element cooperates with the basic body and the stationary element to define therebetween a hydraulic pressure chamber. A plurality of through bores are formed in the peripheral wall of the basic body and axially arranged at predetermined intervals for communicating between the axial hole of the basic body and the hydraulic pressure chamber. A communication hole is formed in the sliding element for communicating between the through bores and the hydraulic pressure chamber.