Research On Control Strategy Of Electric Power Steering System Based On DSPACE

Steering system is the main device to change the vehicle direction,the electric power steering system(EPS)is better than the traditional hydraulic power steering system in energy conservation,environmental conservation and assisting with the speed of the vehicle,it has become the mainstream of today's social steering system.The control strategy is the key technology of EPS and it will affect the safety and comfort,and the good control strategy can directly improve these performance.The development of EPS controller is a long and lengthy process,how to improve the EPS stability and shorten controller development cycle is the key to the whole EPS system research,and the premise and necessary condition of EPS industrialization.In this paper,we can achieve real-time verification and modification of the control strategy by using the EPS rapid control prototype simulation platform,which greatly shortens development cycle and reduces research costs of the EPS.The main research contents are as follows:A linear power characteristics curve is designed according to the structure and operating principle of the EPS.Aiming at the design of the current controller of the power motor,the power control strategy of PID control and Sliding mode control is proposed,and a return-to-center control strategy based on PID algorithm is also proposed directing at the phenomenon that the steering wheel is not enough in the process of EPS return-to-middle.The paper carried on the dynamic simulation model analysis of EPS by combing the vehicle manipulation dynamics model,and establishing the EPS nonlinear simulation model by using the MATLAB/Simulink software.Through the off-line simulation analysis for PID and sliding mode control and return control strategy.The results show that the sliding mode takes more advantage than PID control strategy,and the EPS that return control scheme is added can return faster and eliminate residual angle basically.In order to further improve the simulation results,this paper analyzes the joint simulation of MATLAB and CarSim.Combined with the simulation curve demonstratedthat the EPS system designed in this paper can provide the appropriate steering for drivers,improve the steering portability of the car.Finally,this paper uses dSPACE to build a rapid control prototype simulation platform of EPS system,the semi physical real-time simulation test of power control algorithm and return performance.The test results further validate the design of the power control strategy and return control strategy is correct and feasible,for development and testing in the automotive electronic control system to lay the foundation.