Gain-Scheduled Control for Active Suspension using Estimated Uncertain Parameters

Abstract

This paper proposes a method to improve ride comfort for a vehicle concerning an active suspension. The purpose of active suspension is to suppress the vibration of the vehicle body. The variation of two parameters; sprung mass and tire stiffness, deteriorate ride comfort because the vibration of the vehicle body depends on them. It is necessary to design a controller corresponding to the variations of these parameters. We apply a gain scheduled control for the sprung mass. The control is scheduled by the measurements of some parameters. We estimate the sprung mass using Square Root Unscented Kalman Filter to apply the gain scheduled control. On the other hand, robust control is applied for the tire stiffness. Then, we formulate the active suspension with uncertain parameters as a finite of linear matrix inequalities by using polytopic representation. The uncertainties are put into one matrix using descriptor representation to simply design the controller. We illustrate the effectiveness of the proposed method by simulation and evaluation based on International Organization of Standardization 2631–1.