Design of Adjustable Road Feeling Performance for Steering-by-Wire System

Since steering-by-wire (SBW) system decouples mechanical linkages between front tires and the steering wheel, the road feeling characteristics of SBW system can be designed flexibly to improve the driving experience. In this article, a road feeling system with adjustable performance is proposed based on integrating the elements of the steering wheel module and the steering actuator module of SBW system. In this system, the road feeling torque consists of a main toque and a tuning torque, which are deduced by parametric method. The main torque is to feed back the tire dynamics and road properties to the driver intuitively, and the tuning torque is designed as a compensation of the main torque to tune the road feeling performance. The parameters in the formula of road feeling torque are selected properly and the driver can get the preferred road feeling performance by tuning these parameters in the formula. Next, to obtain the desired road feeling characteristics for different drivers, the sensitivity of formula parameters is analyzed quantitatively according to objective evaluation indices for on-center handling. Then, in the light of moderate type drivers, a set of tuning rules is proposed to determine specific values of parameters. Finally, contrast tests are conducted on the test bench to compare the road feeling performance of SBW test vehicle and electric power steering (EPS) test vehicle to verify the effectiveness of the proposed road feeling system in this article.