Development of a vibration isolation system using an air suspension with automatic damping adjustment mechanism

Abstract

In this study, we develop a vibration isolation system using an air suspension with a variable length slit restriction, clarify its dynamic characteristics, and build a system that automatically adjusts the damping coefficients and equilibrium position of a supported object. The proposed air suspension can provide the optimum equivalent damping coefficient by automatic damping adjustment mechanism. The optimum equivalent damping coefficient, which provides the minimum resonance amplitude, increases as mass of supported object increases. The damping coefficient can be varied by varying slit length of restriction. In order to vary slit length, the damping adjustment mechanism consists of a fixed plate, which has a partially circular groove, and a rotating flat plate faced to grooved plate. The variable length partially circular slit is foamed by two plates. The damping coefficient is almost proportional to an adjustment angle of the rotating flat plate in the adjustment mechanism. The adjustment angle which provides the minimum resonance amplitude can be obtained by equation of the supported mass. The proposed system consists of the air suspension, two pressure gauges measuring atmospheric pressure and static pressure in the cylinder, the damping coefficient tuning mechanism, a servo motor rotating the flat plate to tune the adjustment angle and a micro-computer calculating the optimum adjustment angle using signals of the pressure gauges. Even if the mass increases up to the half as much again and decreases down to the half of it of the nominal value, the minimum resonance amplitude is archived using adjustment mechanism.