Research on hierarchical control of efficiency and stability for in-wheel motor drive electric vehicles

To address the problem that the motor drive efficiency of in-wheel motor driven (IWMD) electric vehicle is affected by frequent changes in driving conditions, and that increasing the vehicle’s own weight of the in-wheel motor (IWM) increases the vehicle’s unsprung mass, thereby affecting stability. To enhance both the driving efficiency and handling stability of IWMD electric vehicles, this paper investigates a hierarchical torque distribution control strategy, constructing a multi-layer controller comprising decision-making, allocation, and execution layers. The decision-making layer employs a fuzzy controller to determine the torque distribution control strategy for the allocation layer. The allocation layer utilizes sequential quadratic programing to solve the motor efficiency optimization objective function based on an efficiency-map torque distribution strategy, while implementing driving torque and slip rate control via a sliding mode control algorithm for the torque distribution strategy. The execution layer provides real-time vehicle state feedback to the decision-making layer, forming a closed-loop control system. Finally, co-simulation experiments using CarSim and Matlab/Simulink, along with hardware-in-the-loop (HIL) testing, demonstrate that the proposed hierarchical torque distribution control strategy effectively improves IWM driving efficiency and vehicle handling stability.