Research On The Positional Detection And Control In Automatic Wheelset Machine

With the rapid development of economic, railway speeding has become an inexorable trend. The wheelset assembly technology is top priority in locomotive bogie technology, which ensures the safety of operation. Automatic wheelset assembly machine has achieved assembly and disassembly automotive process and applied to a variety of rolling stocks include CRH, which integrated with mechanical, hydraulic, computer detection and control. In order to meet the requirement of wheelset assembly technological standard, we developed a position detection and control system of wheelset assembly machine. It can accurately control the distance between backs of wheel flange and the position difference of two wheels through the direct closed loop control of oil cylinder displacement and reference the control strategy and method of numerical control machine to ensure the quality of pressing. The main contributions of this paper are described as follow:(1) Design a position detecting system based on the construction of machine. It use high precision displacement sensor to detect position of every motive unit in real time, through establish three coordinate systems obtain positional relationship of wheel and axle. Furthermore, determine the measuring basis reasonably and calibrate reference regularly can greatly decrease the influence of machine deformation to measuring system.(2) Design the main motion unit’s position control system of wheelset assembly machine. Establish mathematical model of direct drive pump control cylinder system to analysis the influence of press fitting pressure and oil temperature to the operating stability and positioning accuracy. Design the reasonably placement controller to realize the direct position closed loop control, which is based on servo controller.(3) Design a speed controller. In order to eliminate external load fluctuations on the stability of the press-fit process, we design a fuzzy PID speed controller. For the speed controller, the inputs are speed deviation and its rate, and the outputs are three PID parameters. It has a good dynamic response in MATLAB simulation and achieves well control effect through press-fit test. (4) Software implementation of position detection and control system of wheelset assembly machine. In order to displacement and velocity data of hydro-cylinder and measuring system, we design a user interface of automatic wheelset assembly machine by modularized programming language, which is base on PLC and C++Builder.