Multi-Objective Optimal Control Allocation for an Over-Actuated Electric Vehicle

The in-wheel-motor-driven electric vehicle is a typical over-actuated system. The actuation flexibility can be utilized to improve operational efficiency and enhance vehicle motion control performance by allocating different torques to four wheels. Various control objectives are emphasized for different working conditions. To trade off energy optimization and driving stability in actual complicated conditions, a unified control allocation law composed of two-step optimization is developed. A pre-allocation law is carried out for energy efficiency optimization with the assumption that no wheel is skidding or slipping, and a control reallocation law is performed using model predictive control to avoid the vehicle from unstability and to enhance the driving performance. Simulation tests are carried out via a professional vehicle dynamics simulating software veDYNA. The controller is verified to improve energy recovery in routine stable driving conditions and also to dynamically modify torques to ensure the vehicle stability on mu-split and low-adhesion road in extreme conditions.