Theoretical and Experimental Investigation of Electrohydraulic Vibration Isolation Systems

Abstract

This paper presents the results of an investigation of electrohydraulic vibration isolation systems that employ multiple electronic feedback signals to control the action of a hydraulic actuator in a closed-loop servocontrol system. The theoretical basis for the operation of the isolation system is discussed, including consideration of system stability. Experimental data are provided for unidirectional single-mass isolation system configurations that provide limited-band isolation, broad-band isolation, single-notch isolation, combined notch and broad-band isolation, multiple-notch isolation, and notch isolation with automatic frequency tracking. The results emphasize the unique performance characteristics of electrohydraulic isolation systems, including isolation of ultralow-frequency vibration, zero static and steady-state relative deflections, response substantially independent of the weight of the isolated body, and the ability to tailor the frequency-response characteristics to satisfy a wide range of specific requirements.