Research And Design On Dynamic Characteristics Monitoring System Of High-Speed CNC Lathe

High-speed Computer numerical control(CNC) machine tool is a kind of modern sophisticated manufacturing equipment, and its technical level and manufacturing capacity are important symbols of national comprehensive strength. In our country, poorer dynamic characteristics and difficulty of monitoring are important factors which restrict the development of high-speed CNC equipment. With complex system feature of wholeness, nonlinear, non-balance, time-varying and chaos, high-speed CNC manufacturing processing is a nonlinear dynamics system constituted by the connection and effect of multiple resources. So complex system theory should be adopted in the design of monitoring system. The contributions of this dissertation may be summarized as follows:(1) By analyzing the dynamic characteristics, the source of monitoring complexity and features, and researching the applicability of cellular automata of(for) high-speed CNC lathe dynamic characteristics, two-dimensional probability type CA model of spindle dynamic characteristics was developed based on the research of vibration which was the source of the evolution of dynamic characteristics. The simulation showed evolution rules such as variability of vibration strength, variability of sensitive position, variability of boundary vibration.(2) ANSYS Workbench was used to analyze the dynamic characteristics of digital prototype of high-speed CNC lathe. It’s proved that the CA model is proper by comparison of the analyze result with the evolution rules get by simulation.(3) Overall design of high-speed CNC lathe dynamic performance monitoring system was put forward to choose monitoring sensitive position according to simulation result of CA. The core of the system was researched. Firstly, the sensors and installation location was selected according to monitoring sensitive position, the range of measured parameters, correlation of built-in sensors with measured parameter, etc. Secondly, several signal processing methods such as eliminating polynomial trend, smoothing signal, statistical analysis, time-domain analysis and frequency domain analysis was applied to making noise lower and getting dynamic characteristics. Finally, the factors affecting the vibration of the sensitive spot were gained by comparing the output of the BP neural network with the actual monitoring results, which would provide the basis for control decisions.(4) The software of high-speed CNC lathe monitoring system was achieved by the uniting of MATLAB & VC++. By measuring the vibration parameters of the spindle under the conditions of idling and cutting, the natural frequency and dynamic severity were acquired, which showed the practicability of the design.The research and development of dynamic characteristics monitoring system includes complex system modeling analysis, digital simulation test, the actual system design and prototype test. It is good for improving ability of the system, optimizing the monitoring process, perfecting performance of high-speed CNC lathe and it provides a new way of thinking for the performance monitoring and health maintenance of complex equipment.