Steer-by-Wire Front Wheel System Control Strategy Research Based On HILS

Steering-by-wire System(SBW),cancels mechanical linkage between the steering wheel and front wheel,so it gets out of the restriction of traditional steering system and we can design the steering characteristic freely.It is a great innovation of steering system.So there is no conflict between the desirable angular ratio and hand wheel torque. But as it is not so dependable as normal steering system and other power steering system,the hardware-in-the-loop test bench is quite important during these searches.In this paper,we use LabVIEW software and CompactRIO hardware to build a SBW Hardware-in-the-loop test bench. It is a foundation of developing SBW hardware and control arithmetic in the future.SBW hardware-in-loop system contains two core algorithms,vehicle dynamic model and control algorithms.Around these algorithms,we have done the following work:(1) We built a two degree vehicle model to research the steering system.We also designed ideal vehicle transmission ratio in order to improve the vehicle steady-state response.(2) We designed and simulated the SBW upper control strategy to get steering reactive torque and determination of front wheel angle.In this paper,a control model of hand wheel force feedback system was provided,which was used to calculate hand wheel force feedback with wheel speed and velocity.The results of simulation show the modal can meet the demand of "steering feeling".We used yaw rate feedback and full state feedback control strategy to control the target front wheel angle. The results of simulation show that the yaw rate feedback control strategy could improve the vehicle yaw rate response,but could not control lateral side angle and full-state feedback could both improve the vehicle yaw rate and lateral side angle response.(3) We applied V-model to develop the SBW front wheel system. First of all,we set up the mathematical model of front wheel system using LabVIEW System Identification Toolkit.Then the PID control system and the least sample time none-wave adaptive system were designed. Offline simulation and HILS experiment results showed:The PID control arithmetic was simple and reliable;Furthermore,the least shoot follow-up System had greater control result.