Study On The Measurement & Control System And Loading Device For EPS Of Automobile

With the development of high speed in automobile, the requirement of handiness and flexibility on manipulation is increasingly high. The traditionally hydraulic power steering system has limitation of complex structure, high cost, difficult services, and so on, so it has limited scope of application. And that the electric power steering (EPS) is widely spread in small automobile and saloon car, and can improve maneuverability and flexibility.Electric power Steering is high new techno-product integrated of environment protection, saving energy, security, comfortability, which has large difference and brings new effects on steering maneuverability, steering returnability, etc compared with hydraulic power steering. Therefore it is necessary to build a testing system to check and measure performance of every aspect in steering system. Because of the difference between true condition and test-bed, it is necessary to establish a simulated loading device in order to gain ideal steering performance. How to simulate the forces of road and apply it onto the steering system is the premise of doing experiment for performance of EPS of automobile in test-bed. Simplex hydraulic loading and spring loading have not satisfy the required performance, in order to satisfy simulating the requirement of steering resistance at various road condition and velocity, it is needing importantly dynamic loading system to realize it. Theory and experiment are studied on the hydraulic loading.The mathematical model is established firstly on the hydraulic loading in the paper, including electrohydraulic servo and proportional loading. The dynamic performance analysis to the system is also given, including time and frequency responses. The dynamic performances are improved through emendation in order to satisfying the performance of EPS system. Confirming electrohydraulic loading finally after comparing many methods of loading considering performance, price, etc according practical application. A kind of hydraulic loading system, with a proportional electrohydraulic pressure valve as its core component, is presented here.The paper develop a suit of measurement and control software of EPS. The computers carry out the tasks of friendly human-machine interface, easy data acquisition and stable measures of dealing troubles on Lab VIEW platform, and friendly HMI (Human-Machine Interface) measurement & controlling system. Including date acquirement, real time control, signal production, signal disposal module. Date acquirement can gain forces, torque, corner, etc signal of sensor;the realization of proportional pressure valve and electromagnetic direction valve by control module;simulating velocity and engine speed by signal production in order to the design of controller of EPS;signal disposal can analysis in relation to breadth, phase and filter. Based on priorities setting and execution systems selection, a multi-task scheduling based on Lab VIEW for a measurement and control system is presented. These advanced technologies are employed to enhance the performance of measurement and control system. Steady control performance, time, frequency, etc are done by utilizing loading system, measurement and control procedure can further do analyzing and graph drawing.The results of experiments show that hydraulic loading system can satisfy the performances of EPS of automobile. The results of experiments indicate the design of the hydraulic loading and the whole measurement and control system is feasible.