A Simulation Study Of EPS Performance Based On LabVIEW

Automobile steering system plays a vital role for vehicle maneuverability and stability. Ithas developed from traditional machinery system, hydraulic power assisted system,electronically controlled hydraulic power assisted system to electronic power steering systemand will have a further development in the future. Electronic Power Steering System(EPS) is apopular power steering system which depends on electromotor directly providing the steeringtorque and its advantage is that the electromotor can provide the corresponding assistanceaccording to the torque imposed by the driver and the speed signal with the help of computerto guarantee a quick and exact steering return and make sure that the automobile steeringhandily in low speed, running steadily and reliably in high speed. Moreover, EPS is aninnovative and high technology which stick to the theme of modern automobile developmentwith the advantages of saving fuel and being favor of environmental protection and it is theinevitable trend in the development of Automobile steering system.The thesis gives an introduction of the development of EPS, its operating principles,structural composition, main types and advantages as well as the key technology and controldifficulties and elaborates the research status home and abroad concerning the controlstrategies of EPS.In this paper, the PID control strategy and the three basic control modes of EPS whichinclude power control mode, back control mode, and damping control mode are addressed.Based on the detailed analysis of components of EPS system, two degrees of freedommechanical model, steering resistance torque mechanical model and EPS mechanical modelare built to study the steering performance of the electromotor under the proportional controland proportional plus derivative control. On the basis of the current researches, this thesisgives the evaluation methods of vehicle maneuverability and stability. The thesis develops thesimulation system taking advantage of LabVIEW and programs to get the transient responseand the frequency response of steering sensitivity and the road sense and makes a comparative analysis of the influence of control parameters on evaluation indicator under the proportionalcontrol and proportional plus derivative control and makes a comprehensive analysis of theinfluence of other parameters on the steering performance. Finally, the thesis gives anevaluation and conclusion.