Dynamic coordinated control for over-actuated autonomous electric vehicles with nonholonomic constraints via nonsingular terminal sliding mode technique

Autonomous electric vehicles yields wide application prospects due to their inherent capacity of improving traffic safety, and reducing fuel consumption and environmental pollution. However, influenced by the over-actuated characteristic, uncertain nonlinearities and nonholonomic constraints, motion control is considered to be one of the toughest challenges in the exploitation of autonomous electric vehicles. In this study, a double-layer control framework is proposed to construct the coordinated lateral and longitudinal motion control for over-actuated autonomous electric vehicles, which are independently driven by four in-wheel motors. Firstly, a nonsingular terminal sliding mode controller is designed in the upper control layer to determine the desired resultant forces and moment, and the finite-time convergence is guaranteed by the Lyapunov theory. Then, in the lower control layer, a dynamic control allocation algorithm based on the sequential quadratic programming method is presented to optimally allocate the desired resultant forces and moment via coordinating and reconstructing the lateral and longitudinal tire forces. Finally, numerical simulation results show that the proposed control strategy possesses excellent tracking performance.