Robust lateral motion control of four-wheel independently actuated electric vehicles with tire force saturation consideration

The paper presents a vehicle lateral-plane motion stability control approach for four-wheel independently actuated (FWIA) electric ground vehicles considering the tire force saturations. In order to deal with the possible modeling inaccuracies and parametric uncertainties, a linear parameter-varying (LPV) based robust H∞ controller is designed to yield the desired external yaw moment. The lower-level controller operates the four in-wheel (or hub) motors such as the required control efforts can be satisfied. An analytical method without using the numerical-optimization based control allocation algorithms is given to distribute the higher-level control efforts. The tire force constraints are also explicitly considered in the control allocation design. Simulation results based on a high-fidelity, CarSim, full-vehicle model show the effectiveness of the control approach.