FxLMS algorithm with preview for vibration control of a half-car model with magnetorheological dampers

The paper presents a novel approach to the vehicle vibration control using magnetorheological (MR) dampers. Simulation experiments were carried out based on a half-car suspension model including the Bouc-Wen model of the MR damper. It is also assumed that information about the road excitation is available in advance as a preview signal. The tanh-based model of the MR damper was identified according to the Bouc-Wen model response and used to obtain the inverse model that is necessary in the control scheme. The adaptive feedforward LMS (Least Mean Squares) algorithm with a filtered preview signal was modified in order to control the semi-active elements. Because the MR damper can only dissipate energy, it was proposed to decompose the velocity-force characteristics of the damper into a nonlinear passive damper curve and a symmetrical control range of a pseudo active suspension actuator. Such assumption assures that the algorithm can converge to appropriate parameters of the adaptive filter. Deviation of an error signal assumed as kinematic energy of the vehicle body heave vibrations is minimized by the algorithm. Control force generated by the MR dampers and expected by the algorithm is achieved indirectly by the inverse model of the damper. The suspension model was subjected to the road-induced stimulation in the form of series of bumps within the frequency range 0.5-15 Hz. Simulation results obtained for the FxLMS (Filtered-x LMS) and Skyhook algorithms demonstrate an advantage of the modified FxLMS due to its ability to adapt to changing conditions.