Longitudinal Motion Control of Intelligent Vehicle Based on Two Hierarchies Optimal Method

For energy-saving and improving ride comfort, this paper presents a novel development of the longitudinal motion control of intelligent vehicles based on two hierarchies optimal methods. The upper method is the Radau pseudo spectral method (RPM), the lower method is the model predictive control (MPC). The RPM is used for energy consumption optimization algorithm. The MPC is used for the longitudinal motion control method. The longitudinal motion model and energy consumption model are developed. Based on the preceding models, the optimal control problem of energy consumption optimization is established, in combination with the boundary conditions and path constraints. Using the RPM to solve the problem, the optimal vehicle speed trajectory is obtainded as desired input. The longitudinal motion control is completed based on MPC. Simulation results show that, in the case of a pure electric vehicle and an actual planning path, automatic driving at optimal speed consumes less power energy than automatic running at constant speed, and verify the effectiveness of the strategy in the paper.