Research On Key CNC Technique Of The Magnetorheological Finishing Machine Tool

Magnetorheological Finishing (MRF) is a newly developed optical machining method, which can achieve fine-finished optical apparatus efficiently. Combining with electro-magnetics, hydrodynamics and chemistry, MRF has been applied in optical machining. Plane surface, sphere and asphere made of different optical materials can be machined. Optics material such as optical glass, optical crystal and glass ceramic can be machined with MRF. The MRF machine tool is the fundamental equipment to fulfill advanced techniques of manufactory .As a part of the key project,"Research on nano-scaled ultra-smooth surface magnetorheological finishing technique", the MRF machine CNC system was developed and some key techniques such as surface control ,contour control ,servo control and interpolate algorithm are deeply studied in this dissertation.In this dissertation, the general development situation of the MRF machine tool and CNC system are reviewed firstly, and the development and current research work of CNC and ultra-precision machine tool control strategy are summed up. Then according to the MRF machine's structure and motion mode, the function and assignment of MRF machine CNC system are analyzed. The design and implementation of CNC system are researched, and a set of PC-based open architecture CNC system is developed. A trace interpolated algorithm of MRF machine CNC system is advanced according to the characteristic of MRF .The symmetry axis curve surface, such as aspheric surface ,which is fit for optics general equation can be machined with MRF machine by using this interpolated algorithm.The MRF machine servo system decides the machining accuracy, surface quality of the work-piece and productivity. In this paper, the model of servo system transfer function is established by analyzing the structure of servo system and the system model parameter is obtained by using frequency-domain model. According to comproming the tracing error, servo rigidity and disturbance suppression of the servo system, a PID position controller is designed. To improve the system's tracking...