Motor / Hydraulic Systems Combined Control Strategy for Four In-wheel Motor Driven Electric Vehicle.

With improving vehicle stability as objective, an in-wheel motors / hydraulic brake system combined-control strategy is designed for four-wheel motor driven vehicles. The controller adopts layered control structure : the upper layer applies sliding mode variable structure theory to obtain the generalized force, while the lower layer uses quadratic programming method to optimize torque distribution, with consideration of the position and speed constraints of actuators. A CARSIM / MATLAB co-simulation is conducted for algorithm verification. The results show that under critical conditions, vehicles without control or controlled only with in-wheel motors can not complete the simulated operation, while the vehicle with in-wheel motor / hydraulic brake system combined-control strategy can assure the handling stability of vehicle. [ABSTRACT FROM AUTHOR]