Design And Verification Of EPS Control Strategy And Test Bench Based On DSPACE

With the development of electronic industry,Electric power steering system which with the advantages of low cost,low energy consumption and high performance has been occupied a large share of steering system market of the passenger car.Our country’s EPS supply chain with independent intellectual property rights has become mature.However,there is no commercial application in EPS test bench in our country,which is far from that of foreign countries.EPS test bench plays a important role for the development of EPS.In the laboratory,it can realize the EPS preliminary practical verification,online modification and debugging in a short time and limited space,to short the development cycle,and reduce the cost of human and material resources.Primarily,according to the vehicle parameters of the research object,the Vehicle dynamics co-simulation model is established by MATLAB/Simulink and Car Sim.Based on the analysis of steering resistance torque,the model of steering resistance torque under different working conditions is established,which realize the real time calculation and output of vehicle steering resistance torque.Secondly,through the force analysis of C-EPS,the dynamic model of C-EPS is constructed.Based on steering resistance torque model,linear assist characteristic curve with conic transition is designed.The conventional PID controller is used to control the steering assist and steering wheel return,and the genetic algorithm is used to optimize the parameters of PID controller.The C-EPS control strategy is designed.Jointing steering resistance torque model,C-EPS model and control strategy for simulation.The results show that good control results are obtained in the simulation of steering portability,assistance step response and steering wheel return performance.Thirdly,C-EPS hardware-in-the-loop test bench is developed by dSPACE.In terms of hardware,the mechanical structure of the test bench,the steering torque loading mechanism and the transmission mechanism are designed,the sensor and assisted motor driver are selected.In terms of software,the code generation of control strategy is completed,and the man-machine interface of test management is established by using controldesk.Hardware-in-the-loop simulation results show that the C-EPS control strategy has good performance,and the test bench achieves the expected design goal.Finally,to further improve C-EPS safety,an unknown input observer insensitive to the disturbance input of C-EPS is designed for the failure of C-EPS sensor.It can estimate and decouple the sensor fault.The active fault-tolerant control of C-EPS is established.The active fault-tolerant control simulation experiment is carried out for torque sensor and current sensor.The simulation results show that the active fault-tolerant control can estimate the sensor fault value in real time,and realize the recovery of C-EPS assist performance under torque and current signal fault respectively.