A robust three-layer integrated control strategy for path tracking of A-DDEVs: Addressing coupling, disturbances, and over-actuation

To solve the issues of dynamic coupling, parameterized modeling errors, external unknown disturbances, over-actuated characteristics in the path-tracking control of autonomous distributed drive electric vehicles (A-DDEVs), this paper proposes a new hierarchical integrated control strategy. Firstly, in the upper level, the expected vehicle state satisfying the control objectives is derived using the backstepping method, transforming the path-tracking control problem into an integrated motion control problem to reduce the system control dimension. Secondly, in the middle level, a new integral logarithmical sliding mode surface is proposed, and an integrated motion controller is designed based on adaptive sliding mode control and fuzzy logic system to determine the desired longitudinal driving force, front wheel steering angle, and additional yaw moment required to track the expected vehicle state. Then, in the lower level, a tire forces distribution controller is designed with the weighted sum of tire load ratio and motor energy loss as the optimization objective. Simultaneously, a wheel slip ratio controller is designed to adjust the distribution results, thereby obtaining the desired motor torque to achieve the overall control objectives. Finally, the simulation experiments are carried out using the Carsim-Simulink platform. The simulation results exhibit the effectiveness and robustness of the proposed control strategy.