Electric Power Steering System Simulation And Hardware In Loop Simulation Based On CarSim

Within the whole technical processing of vehicles, the advantages like energy conservation, environmental friendly, frequent adjustment availability and compacted structure had assisted electronic power steering system been recognized as a new direction of vehicle steering technology development. Therefore, the control strategies of EPS’s controller and the simulation platform for hardware in loop were cardinally investigated in accordance with design simulation method and hardware in loop of ECU’s V flow diagram.First of all, as a simulation target, a mini SUV was analysed about dynamic features, mainly aimed at the mechanical steering and power-assisting motor unit of its EPS system, the double layered control strategy was designated to EPS, then, the motor controlling procedure and straight type power-assisting plot design was conducted. To be more specific, for the power-assisting strategy, there were two algorithms designed, one of them based on traditional PID control, the other adopted sliding mode control. For alignment control strategy, the PID method also been used.Then, the MATLAB/Simulink EPS simulation models constructing of mechanical motor, power-assisting motor and controller were carried out, so did simulating, result comparison and analysis. In order to complete the simulation, a full vehicle model from CarSim, the vehicle dynamic modeling software, was adopted to cooperated simulate with Simulink. The collaborative simulation confirmed the effectiveness of the power-assisting and alignment control strategies the paper represented. The results shown:hand wheel torque dramatically declined with EPS installed, which means the designed EPS system would light the steering processing. And hand wheel returnability was performed rather faster in both high and low vehicle velocity conditions when put the alignment controller in. Besides, sliding mode control strategy has better current tracking performance compared with PID method, because of its condition adapted structure.Finally, the PXI equipment of NI Co. was adopted to conduct hardware in the loop investment, simulation also ran in accordance with the corresponding national standards. The constructed platform was based on co-simulation of CarSim and LabVIEW RT. The simulation result represented that the platform was able to carry out EPS performances researches. Within laboratory environment, the vehicle steering performance test could be done by using CarSim vehicle model, and it would result in obvious consequences. Meanwhile, the test result also clarified that the designed EPS controller was apt at effective improvement of steering portability and returnability performance.