A flexible control allocation method for terminal understeer mitigation

Abstract

This paper addresses the problem of terminal understeer of a road vehicle. The scenario is considered when a vehicle enters a curve with excessive speed and the aim is to apply automatic chassis control to prevent the vehicle from drifting out of the lane. In a previous study, the optimization problem is formulated as the minimization of maximum path off-tracking and the optimal response of a particle model is in the form of a parabolic path recovery (PPR) where the acceleration vector is fixed in the global frame. A recently developed model based control method the Modified Hamiltonian Algorithm (MHA) uses this acceleration information as a reference for control allocation to each wheel. The controller is developed using a simplified 3DOF vehicle model in Matlab and Simulink environment. In this paper, we consider using a high fidelity model in CarMaker to verify the control performance. It is of particular interest to see how well the chassis control can deal with the inherent understeer and oversteer qualities of the vehicle. Hence in this paper we evaluate the ability of an active safety system to overcome the mechanical limitations of the vehicle.