| Electric power steering system is the most widely used power steering system at present.The importance of its main dynamic performance is self-evident,and the vibration mode is also an important performance that can not be ignored.The various performance indicators of electric power steering system are interrelated and interacted with each other,and belong to different disciplines.At present,it is difficult to guarantee the performance of vibration modes by only optimizing the dynamic performance.Therefore,taking the electric power steering system as the research object,considering the influence of vibration model,multi-disciplinary optimization design method is adopted to optimize its parameters and performance.The main contents of this paper are as follows:Firstly,the dynamic model of the electric power steering system and the vehicle is established.The steering system model includes the steering wheel input axle model,the output axle model,the gear rack model and the power motor model.The finite element model of the electric power steering system is established,which lays the foundation for the modal analysis and optimization design of this paper.Secondly,the steering road feel,steering sensitivity and steering stability are proposed as the performance indicators of steering system,and the quantitative functions of each indicator are established.Considering the influence of vibration modes on steering system performance,the Latin hypercube experimental design was used to obtain design variables,and the response surface approximation model of modal performance index was constructed.Finally,the idea of multi-objective optimization is introduced into the traditional collaborative optimization algorithm,which takes the comprehensive performance of steering system as the main system,and takes road feel,steering sensitivity,steering mode and steering lightweight as the subsystems.A collaborative optimization model of electric power steering based on dynamic constraints at system level is constructed,so that the single-objective collaborative optimization of the traditional main system can be transformed into multi-objective collaborative optimization of the main system.Collaborative optimization and particle swarm optimization are used to optimize the design of electric power steering system.The results of this study can provide a theoretical basis for the design and development of electric power steering system. |
