Study on the stability of the steering torque feedback system considering the time delay and the system characteristics

The steering torque feedback system, as one of the most critical parts in a driving simulator or a steer-by-wire system, is used to generate an faithful or desired steering feel for drivers. This requires that the steering torque feedback system should stably simulate the steering feel for a sufficiently large range. There are many factors that can influence the stability region of the steering torque feedback system, such as the characteristics of the system, the time delay and other non-linear factors. In this paper, from the viewpoint of the system design, a stability criterion is derived using an energy-based approach. In particular, some influencing factors are quantitatively investigated and analysed in this paper, including the characteristics of the damping, friction and stiffness system, the time delay and other non-linear factors of the system. The stability criterion and the analysis results of these influencing factors can be used as guidelines for the design of a steering torque feedback system with the aim of achieving a better performance, such as appropriate parameters for the system damping, friction and stiffness, the maximum allowable time delay of the system and the design of the system control algorithms. As well as a finished steering torque feedback system, the stability region can also be calculated from the criterion using the system parameters. The derived stability criterion and analysis results of these influencing factors are all verified by both simulations and experiments.