Steering Torque Estimation for Distributive Steering System in Electric Vehicle Steer by Wire System

The introduction of vehicle steer by wire (SBW) system technology permits customization dynamics of vehicle behavior by ability to tune the steering system response. This improves the vehicle performance, maneuver, and stability. However, the challenging issues in SBW system, is how to generate the steering torque. The important of steering torque is for a driver steering feel. With this sense of feel, driver has more confidence level during maneuver. Moreover, this torque used as function steering wheel returnability is whereby, when driver releases their handoff from the steering wheel, a steering return back to its initial position. In conventional steering system, this torque is created from the contact between tire and road surface. This torque then follows through column shaft and directly to the driver. However, in SBW system, this column shaft is eliminated and replaced with sensors and actuator. Therefore, in SBW system, this torque has to be artificially generate and control. This paper proposes a method of generate steering torque for SBW type of distributive steering system. The torque of front wheel motor left and right is taken into account to generate steering torque. The compensation torque is applied to improve the driver steering feel and classical controller used to control the torque. The mathematical numerical analysis is conduct to show the effectiveness of proposed control algorithm and compare with EPS steering system as a benchmark. Based on finding results, the proposed control algorithm able to generate steering torque in parallel provides driver steering feel during maneuver.