Modeling and simulation studies on differential drive assisted steering for EV with four-wheel-independent-drive

A novel power assisted steering system was proposed in this paper, due to the independent driving characteristics of electric vehicle (EV) with four-wheel-independent-drive. The basic theory of differential drive torque assisted steering is discussed at first. After that, vehicle dynamics model with steering system was built in SIMULINK, and the control strategy for minimizing the difference between the reference steering effort and the actual steering effort by controlling the drive torque distribution between the wheels of two sides of the vehicle body was constructed. The simulation results showed that, to four-wheel motored EV, the proposed differential drive torque assisted steering can reduce the steering efforts to a reasonable level obviously, and ensure the most possible road feel feedback to the driver. Moreover, it can improve return-to-center performance of the steering system.