Active vibration isolation of a simulated engine response

Abstract

Vibration isolation is prevalent in many industrial applications. In the automotive industry two factors arise amidst many others . cost and mass reduction. As these factors are implemented in the design of the modem automobile, vehicle vibration and noise performance suffer. This study presents a hybrid solution, involving active and passive isolation, to satisfy static and dynamic behavior of the vehicle engine response at idle conditions. An engine simulator was designed to produce a forced vibration response with two harmonics. The projected bandwidth will resemble idle conditions, since external perturbations such as road and wind noise will become prevalent at higher vehicle speeds. Feedforward and feedback control schemes are used to cancel the induced vibrations. An analytical model involving a three degrees of freedom kinematic model and a four degrees of freedom electromagnetic circuit was implemented into a computer code. The computer code involves an IMSL routine to solve for the natural frequencies and a numerical integration method to obtain the steady state response. Experimental results presented illustrate a significant reduction in the transmitted force for the feedforward and feedback cases.