Research On Parameter Optimization And Robust Control Reduction Of Steering-by-Wire System

Steering-by-wire system cancels the mechanical connection between the steering wheel of the automobile and the steering gear so that the steering system force and angle characteristics can be freely and flexibly designed,so as to improve vehicle safety,comfort and operation stability,is the future development trend of automobile steering system.In order to improve the safety and steering stability of the vehicle,this paper studies the system modeling,parameter optimization,robust control system design and reduced order of the steering-by-wire system under the framework of multidisciplinary design optimization method.The main contents as follows:Firstly,by analyzing the structure and principle of the steering-by-wire system,the dynamics model of the steering-by-wire system and the two-degree-of-freedom model of the vehicle are established.Secondly,put forward the new vehicle steering performance evaluation index and deduced its mathematical expression.Based on the dynamics model of the steering-by-wire system and vehicle model,simulate and analyse the steering feel and sensitivity optimization model by use of Isight of multidisciplinary design optimization software and Maltab toolboxes and obtain the optimal values of the parameters of the steering system.The stability analysis of each parameter and important parameters are studied by Matlab software.Then,based on the steering-by-wire system model and parameter optimization,the H∞ robust controllers of the steering-by-wire system are designed and implemented.Finally,in order to reduce the order of the H∞ robust controllers,the reduced-order control design and system performance analysis of the control system are carried out.