Study on Steering Torque Characteristic for Steer-by-wire Vehicles

Since the partial mechanical connections between the steering wheel and the front steering wheels cancelled, the steering resistance torque of the Steer-By-Wire vehicle can't be directly feedback to the driver. From the perspective of the driver's preferences steering wheel torque, and based on analyzing the influence factors of steering torque, a steering torque model of the steer-by-wire has been established by considering the friction torque, damping control moment, limit control torque and active return moment. And the parameters in the model are identified by the experimental data. The lemniscate test, on-center characteristics test and other tests are carried out through simulation analysis and hardware-in-the-loop validation. The results show that the steering wheel torque model can not only ensure steering portability at low speed and steering feel clear at high speed, but also describe steering wheel torque characteristics well at different driving conditions. It gives full play to the advantages that steering torque of steer-by-wire vehicle can be designed freedom according to the needs of drivers. © 2018 Journal of Mechanical Engineering.