Research On Comprehensive Performance Test-bed Of EPS System With Variable Load

Electric Power Steering(EPS)is a power steering system that uses the torque output from the motor to help the driver to turn the vehicle.Its performance determines the safety,maneuverability and stability of the vehicle.Therefore,it is essential to test the performance of the EPS system using the test bench.With the rapid development of the EPS system,the accuracy requirements of the development of the EPS system by various manufacturers are getting higher and higher,and the traditional EPS test bench can no longer meet the requirements of the market.The variable load EPS system comprehensive performance test bench studied in the thesis can not only effectively avoid the unsafeness of the actual vehicle test,but also reduce the test difficulty and cost of the EPS system and shorten the development cycle of the controller.The paper mainly develops the performance test of the steering shaft assisted EPS system.Defining the test items of the test bench,the overall structure and working principle of the EPS system are analyzed,the simulation model is established,and the two-degree-of-freedom vehicle model is co-simulated to establish the simulink simulation model of the variable load EPS test bench,which verifies the feasibility of the test bench and summarizes the overall design principles and requirements of the test bench,and the overall design of the test bench was determined.Designing the overall gantry structure of a variable load EPS test rig.The steering system and the road surface resistance system were simulated by the dual servo motor system.The acquisition and processing of analog signals from input and output dynamic torque sensors,current sensors,encoders and on-column torque sensors using a capture card.Using a programmable logic controller(PLC)to connect external buttons and output vehicle speed and speed pulse signals;using a CAN card to output vehicle speed and speed of EPS controller with CAN protocol;the hardware design is completed according to the module requirements of the variable load EPS test bench test function.Designing PLC control program to achieve different functions according to different trigger buttons.Using LabVIEW to develop the test software,designing a friendly human-computer interaction interface according to the requirements of use.and implementing the functions of the front panel in the block diagram.The main program uses the mode of the producer consumer cycle,and the program modules such as data acquisition,parameter setting,steering resistance torque loading,and CAN communication are packaged and called in the program block diagram of the main pro:gram.According to the detection procedure of the variable load EPS test bench,the function is debugged,the EPS system is detected,and the test results are analyzed in detail.By comparing with the actual working parameters of the EPS system and the test results of the standard test bench,the reliability of the EPS test bench with variable load and the eligibility of the EPS system were verified.