Smart Active Suspension to Counteract Dynamic Load Changes during Critical Maneuvers.

Abstract

This paper presents an adaptive control approach to a general multi-degrees-offreedom suspension model. A half car model, which involves bounce and pitch degrees of freedom for sprung mass and bounce degree of freedom for the unsprung mass is considered. The control concept diverts from the widely applied optimal control to adaptive control. The basic idea involves obtaining optimal performance of any nonlinear time varying suspension model by adaptively following a predefined reference model. The controller is designed for the first time to compensate for Squat and Nose-diving in the pitch mode of the vehicle during acceleration and deceleration maneuvers respectively. Discrete Model reference Adaptive Control (DMRAC) with parameter estimation is used to derive adaptation laws for the controller. The proposed control scheme is found to be computationally fast and does not require a priori knowledge of complex and nonlinear dynamic model and time varying parameters of the model. Simulation results for half-car model with all nonlinear suspension components subjected to deterministic input are presented. The results indicate good performance of adaptive controller even for large parametric variations in the model due to critical acceleration and deceleration maneuvers.