An Investigation Into Test System Of Electric Power Steering Performance

With the aggravation of the world’s energy and environmental crisis, electric vehicles, as a new clean energy vehicles, could deal with the energy crisis, reduce air pollution, reduce carbon emissions, and represent the direction of the automotive industry’s future. As the key device to change the direction of a moving car, the performance of a steering system will directly affect the stability and security of the car’s handling, which plays an important role in protecting the safety of the driving vehicle and improving the comfort of the driver’s steering. As EPS is gradually becoming popular in car assembly, the performance testing, especially online testing becomes an urgent need for automotive industries.Under this background, the project carried out an investigation into the car EPS performance test system based on the technical specifications and bench test method for EPS on vehicle. An EPS performance test system based on industrial control computer has been developed.This article first studies the structure and working principle of the EPS system, then builds the EPS system dynamics model, analyses the relative performances, and lays a theoretical foundation of the EPS performance test system for the following sections.After the analysis and identification of the basic function of the test system, the general scheme of the test system was determined. By comparing the advantages and disadvantages of three kinds of system control schemes,, the industrial control system was chosen as the system control scheme. The servo motors were applied for system torque loading taking into account the online testing needs and economic reasons. Then, the appropriate sensors, signal conditioning, data acquisition cards, servo motor and motion control cards were used to complete the set up of hardware platform.In modern test systems, hardware is the base, software is the soul. Considering the system functions, the software development cycle and other factors, Windows XP is selected as a software development environment, Visual Basic being selected as a development tool. The software system using modular programming, carries out system initialization, motion control, data acquisition card, data analysis and processing functions, thus completing the construction of the test system software.With the electric power steering performance test systems, the testing items can be conducted including the force characteristics test, input and output test, the sensor test, functional test and load test. Also the test methods and performance evaluation parameters of the system were discussed.