Research On Automatic Door Control System Of Urban Rail Vehicles

With the continuous development of the new urbanization in China, the weak transport power of urban appears. Urban rail transit, as a safe, fast and green mode of transportation, can greatly improve the weak transport power of urban. Automatic door, which is related to the safety of passengers, is one of the frequently used equipments in the operation of urban rail vehicles. Train delays caused by automatic door failure and casualty accidents are not uncommon. With the development of science and technology, the electric control door as a new type of automatic door system gradually replaces the traditional pneumatic control door. The electric control door system based on brushless DC motor has great advantages in terms of reliability, stability and service life. Therefore, the research on the automatic door control system of urban rail vehicles based on brushless DC motor is of great significance. On the basis of analyzing the structure and functional requirements of the automatic door, the three aspects of automatic door system that control performance, commutation torque ripple and anti-extrusion function of automatic door are studied in depth and several methods are proposed to solve these problems of automatic door system. Then the software and hardware of automatic door control system are designed by combing with the TMS320F2812 DSP control chip of TI company.Firstly, a variable-sampling discrete sliding mode controller is adopted to improve the control performance of brushless DC motor with low resolution position sensor on the basis of the traditional discrete sliding mode controller. The stability of the movement of the automatic door is improved and the vibration and noise of automatic door are reduced by using mode of PWM_ON, which can restrain commutation torque ripple of brushless DC motor. The accuracy and safety of anti-extrusion function for automatic door are improved by using the method of multi-segment activation and current protection in view of train delays caused by error of anti-extrusion function. In addition, the feasibility of the proposed methods are proved by experiments.Secondly, the hardware of automatic door control system of urban rail vehicles is designed according to the composition and functional requirements of the automatic door. DSP control circuit, brushless DC motor drive circuit, detection circuit including current, position and speed, and protective isolation circuit are included.Finally, the software of the automatic door control system of urban rail vehicles and the interface of the upper computer are designed based on the hardware and Visual C++ 6.0. In addition, the working condition and control methods of brushless DC motor are proved. The control software of automatic door control system of urban rail vehicles includes the self learning program of gate-width parameter, the speed curve program of automatic door, the ant-extrusion function program of automatic door and the control program of the brushless DC motor driver, and so on.