Fuzzy Control of Electric Vehicles for Understeer Prevention

In understeer manoeuver, lateral tire forces of front tires are saturated. Thus, the widely-used linear tire model in yaw stability control is no longer suitable for understeer prevention. Moreover, the longitudinal motion is neglected and only the lateral and yaw motions are taken into account in the dynamic model. To overcome these shortcomings, a new tire model and a control strategy are proposed in this paper. First, a piecewise affine (PWA) model is established. Next, a 3DoF dynamic model is obtained based on the new tire model. Finally, a fuzzy yaw stability controller is designed based on the T-S fuzzy model representing the above dynamic model. Simulation results show that the nonlinear lateral force can be approximated by the PWA tire model accurately, and the control strategy is efficient for understeer prevention. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.