Application of an Optimal Control Algorithm on ABS for an Electric Vehicle

Promotion of pure electric vehicle (EV) has become a trend, of which the braking performance is very important. In this paper, by using a family of curves of the relationship between adhesion coefficient and sliding rate of an electric vehicle on different roads, to elect the sliding rate corresponding to the peak value of adhesion coefficient, and then the mathematical models of EV braking process are established and the dynamics differential equation is obtained. According to the optimal control theory, appropriate state vector and control vector based on the dynamic mathematical model of vehicle-road system are selected, and a quadratic performance index of the minimum error between actual output and expected output with the minimum energy consumption of the hydraulic braking system in time domain are proposed as well. Typical working condition parameters are selected as the initial condition to calculate series of control parameters of the optimal control model by Riccati matrix algebra equation. In MATLAB/simulink vehicle anti-lock braking system model is established, and by simulation graphs of wheel velocity response show that, the wheel velocity can satisfy the slide requirements well by using optimal feedback control algorithm for EV with more advanced ECU system.