Development Of C-EPS Controller For PMBLDC Motor Based On CAN Bus

Electric power steering(EPS) system is growing its popularity these days among auto parts manufactures, universities, and research institutions, since more and more vehicles are equipped with this burgeoning power-assisted steering technology. Most of EPS developed in China apply brush motors as the source of assist force and lack functions of communication with vehicular network, which is mainly sold in low-end market. This article researches an EPS controller for permanent magnetic dc brushless(PMBLDC) motor with CAN bus comm--unication function.The main work are shown as follows:(1) The function and operating principle of EPS system, especially the drive principle of PMBLDC motor is analyzed, based on which the main framework of controller is determined and the concept design is accomplished.(2) The hardware electric circuits design theory is studied. Electric circuits of ea--ch functional modules are designed using Altium Designer software and the PCB pro--totype are made. Finally, the circuit layout and electronic component models are dete--rmined after debug process. The main function of hardware is archived.(3) C code for Freescale MC9S12XS128 is programmed in Code Warrior development environment. Functional registers are configured referring to the date sheet. Flowcharts of software are designed according to which the program is written. Debugging work is carried out using background debug mode method. Software function, such as signal capture, motor control, etc., is achieved.(4) CAN bus communication mechanisms and message protocol is studied. The inde--pendent CAN protocol is established on CANoe development platform. Communication between EPS ECU, panel ECU and engine ECU is achieved in simulation. The validation of protocol and software & hardware of CAN module is verified through HIL test.(5) PMBLDC motors are customized and manufactured, and installed in C-EPS assembly, replacing the original brush motor. Bench test that measures torque of steering wheel input and column output is carried out, which proves the effectiveness of EPS controllerThe EPS controller he main functions of which are PMBLDC motor control and CAN bus communi- cationis developed according to typical vehicle E/E system development process, t. It can be concluded from the development process that torque ripple elimination and fault detection are technical challenges to future research.