Parametric design and application of steering characteristic curve in control for electric power steering

Electric power steering (EPS) is considered as the future of power assisted steering technology for passenger cars. In this paper the authors study the process of how to design the steering characteristic curve, analyze the steering characteristic curve using the driver’s steering feel, and proposes a power sinusoidal steering curve, which is parametric and can be altered easily in the prototype tests. Furthermore the authors study the detecting process of steering torque sensor in EPS control systems, and distinguish between actual steering torque and an ideal one. Using this way the authors deduce a formula to calculate the reference torque, which is based on the variation of the system loads. Finally, experimental results on certain vehicles have indicated the feasibility of the adjustable parameters and the effectiveness of the deduced formula.