The time-delay coupling nonlinear effect in sky-hook control of vibration isolation systems using Magneto-Rheological Fluid dampers

Abstract

The effect of the nonlinearity and time delay in the Magneto-Rheological fluid (MRF) damper on an isolator system is studied in this study. The mechanical model of the control force of the MRF damper in the skyhook control is introduced as nonlinear piecewise function. The displacement transmissibility of the isolation system is solved by employing the Averaging method. The isolation effectiveness for different values of control coefficients is demonstrated by the displacement transmissibility. The increasing of damping control force of MRF damper reduces the displacement transmissibility to a low level while time delay has different functions in different frequency bands. Moreover, by the analysis of eigenvalues in the manifold given by Averaging method, the unstable and stable region of the steady state can be decided on the parameter plane, which provides the bifurcation criterion induced by nonlinearity and time delay. The main results from theoretical analysis and experimental prototype give an insight into the analysis and design of semi-active control with time delay in control loop and signal processing for isolator system by exploiting nonlinear benefits in vibration suppression effectiveness.