Feasibility and performance analyses for an active geometry control suspension system for over-actuated vehicles

Abstract

To build an over-actuated vehicle, the chosen equipment is composed of an active four-wheel drive and steering systems, a torque vectoring system, and an active braking system. In general, the goal of the over-actuated vehicle is to improve stability and handling performance for both conventional and autonomous vehicles. This paper presents an active geometry control suspension system (AGVS), based on a 3-DOF parallel mechanism, which is capable of acting simultaneously on the camber, the rear-wheel steering and the body roll angles. The aim of this study is to analyse the performance and feasibility of this active suspension mechanism when assembled in a C-class vehicle. These analyses were developed through a co-simulation scheme implemented in CarSim and Simulink software for three different manoeuvres: steady-state cornering, fishhook and double lane change. The performance analysis provides a comparison of the same C-class vehicle equipped with different systems, from the original to the fully actuated one. The conducted simulations reveal how superior a multi-purpose control system is when compared to the other single-actuated systems, and how it can manage the necessary trade-off among the selected metrics, namely, the roll gradient, the understeer gradient, the yaw rate, the body roll angle, and the lateral acceleration. In the feasibility analysis of AVGS the demanded actuator power and force in typical manoeuvres was assessed. In addition, the required ranges for the camber and rear-wheel steering actuations, as well as for the mechanism joints, were determined. The vehicle equipped with AGVS demonstrates improvements of dynamic behaviour in both steady-state and transient manoeuvres. © 2022, The Author(s), under exclusive licence to The Brazilian Society of Mechanical Sciences and Engineering.