Passenger-Oriented Intelligent Suspension with a Biodynamic Model and Skyhook Control

Abstract

Intelligent suspension systems assist in decreasing the impact of road disturbances on passenger comfort, and its design requires a mathematical analysis that includes the elements of the suspension and the passenger's vertical dynamics. The contribution of this research is to merge a 4 degrees-of-freedom (DOF) Boileau-Rakheja biodynamic passenger model with a 3-DOF suspension model to generate more accurate representations of the displacements and accelerations of the main passenger's masses. Moreover, the contribution is complemented with a Skyhook controller in a semi-active 7-DOF one-quarter vehicle suspension to improve passenger comfort, and a case study presents tests in frequency and time domains. The analysis was conducted by establishing a regulatory closed-loop feedback control for a state-space system, simulating its behavior using MATLAB/Simulink, and comparing the results against specific performance criteria. The active suspension's frequency response showed a 40% reduction in the displacement transmissibility of the suspended masses at low frequencies (0-4 Hz), but exhibited a 2-10% increase in the rms acceleration at high frequencies (4-15 Hz). The herein results could be the base for further studies in the passenger comfort and road holding for one quarter, but also for half and full vehicle.