Robust semiactive control of a half-car vehicle suspension system with magnetorheological dampers: Quantitative feedback theory approach with dynamic decoupler

Abstract

Thisarticle presents the quantitative feedbacktheory(QFT)basedmultivariable controller for the vertical and the pitch angle motion of a half-car suspension system. A coupled half-car system with significant uncertainty, due to sprung massesvariation,posesachallengingcontrolproblem.Multi-inputmulti-output (MIMO) QFT method is used for this purpose which involves converting the actual MIMO system into an equivalent single-input single-output (SISO) sys tem so that the design problem is carried out using the SISO QFT principles. The proposed idea is centered on by converting the coupled MIMO system into a decoupled oneusingthedynamicdecouplerwhereincontrollers are designed independently based on the equivalent SISO system. The designed QFT-based controllers with the decoupler use the semiactive suspension strategy (real ized using the magnetorheological (MR) damper) to reduce the vibration of the half-car suspension system (in vertical/pitch angular motion) and hence to increase the ride comfort and the vehicle road holding. The feedback cost is less in the proposed design than the sequential QFT design. In this study, the MR damper dynamics is captured by the first-order model which is realistic, effi cient, andsimpleform.Extensivecomparativesimulationstudiesarecarriedout to illustrate the effectiveness of the proposed design over the existing methods such as passive and skyhook control under different road excitation.