Research And Design Of Automobile EPS Controller Test System

Automobile Electronic Power Steering System(EPS) is gradually replacing other types of power steering system on production automobiles due to its excellent performance. Thus, the demands of research and production of domestic EPS are very imminent. In recent years, a number of auto parts production base have been built and begin to product EPS. Controller which is the core unit of EPS is the brain of whole system and determines the quality of EPS in a large part. Strict tests must be taken in the factory test to ensure the quality of EPS controller which has various types for different manufacturers. Test instruments developed by traditional method could not meet the factory test requirements for EPS controller which has various models and a large number of test items. Therefore, it has became an urgent need for the EPS controller manufacturers to design a general and efficient test equipment.This thesis focuses on solving the problem of versatility and efficiency in the test system of EPS controller testing. The general design of the testing system is achieved from both hardware and software aspects. In terms of hardware, Slot chassis was choosed to establish hardware board intergration, which was convienient for the board to replace, upgrade and maintain; Simulation load was designed by the way of modular and slot interface, which has improve the structure flexibility and expansibility compared with traditional analog load form. A a high density and reliability matrix board was used to connect board terminal, load and test end; Standardized fixture interface was designed to realize the pin connection of different types of EPS controller by using reconfigurable probe structure. In terms of software, different types of EPS controller test file were generated by using NI Test Stand to achieve universal design of test program.To achieve a higher efficiency for the test system, PXI bus and dual-core PXI-8108 computer were selected as the hardware platform to improve the data processing speed. In terms of software design, multithreaded main program was written to achieve real-time multitasking processing by using Lab VIEW; NI Test Stand was used to call test procedures directly to improve the efficiency of program execution.In this thesis, combinational logic interface circuit designed by relay solves the problem of power line current test under uninterruptible power supply conditions, which achieves single digital multimeter voltage and current test circuit switching. Isolation protection circuit was designed to enhance the security of the test system. According to actual needs, fault diagnosis module was designed to improve the reliability of the test system.In addition, this thesis studied the methods of evaluating overall usability of the test system and designed the data statistics and analysis program to evaluate the reliability of the test system by using Lab VIEW development platform.Finally, the practicability of system has been proved by testing some key parameters(voltage, current and PWM waveform paremeters), missing rate, false detection rate and testing cycle. The result shows that the designed test system can achieve the design requirements which could meet the requirements of various types EPS controller test.