Control strategy for front wheel angle of steer-by-wire based on variable steering ratio

In order to improve the performance and stability of the steer-by-wire system, this paper presents a hybrid-intelligent based variable steering ratio front wheel control algorithm. The factors that could impact the performance and stability of the steer-by-wire system are analyzed at first, according to the requirements, the fuzzy neural network based steering ratio controller is designed to control the steering performance of the vehicle as a key point, and the linear fitting based steering ratio controller is designed to control the steering stability as another key point, and then the vehicle state is judged by the vehicle stability indices, the fuzzy soft-switch approach is utilized to switch the two controllers according to the vehicle state, eventually, the proper steering ratio that meets the performance and stability is obtained. The proper steering ratio is utilized to control the front wheel angel directly, and the control strategy is brought into the model for simulation experiment, simulation results show that the proposed control strategy is effective and feasible.