Part II: Control of a One-Degree-of-Freedom Active Hydraulic Mount

Abstract

In the first part of this investigation, a model of an active hydraulic mount was developed using the method of conic sector bounding to capture plant nonlinearities. The purpose of the mount is to make a mass that is driven by an external force and a hydraulic actuator behave as if it were a prescribed mechanical impedance driven solely by the external force. A two-degree-of-freedom control system, that consists of a feedback controller and a prefilter, is proposed as a solution. A position-velocity-acceleration (PVA) feedback controller using classical root locus methods and an H2-optimal feedback controller are designed using the plant model. A prefilter is then used to prescribe the mechanical impedance of the mount. The performance of these control systems is investigated in the frequency domain using Robust Control Theory. Finally, numerical simulations of a high-fidelity nonlinear model are used to assess the performance of each controller in the time domain.