Research On Fuzzy Control Of Large-Stroke Micro-Feed Mechanism

With the development of ultra-precision machining technology, micro feed mechanism is widely used in the field of ultra-precision machining. It can achieve precision micro displacement, and can also compensate error in the process of cutting in order to guarantee the precision and surface quality. So micro feed mechanism and its precision control have been became an important part in the field of ultra-precision machining. The study in this paper is very important for improving machining precision and the quality of work-piece surface.Combining with large stroke, high-resolution stepper feed mechanism based on piezoelectric actuator,the common micro-feed mechanism based on the piezoelectric actuator has been introduced. Piezoelectric actuator and the main characteristics and control methods of piezoelectric actuator at home and abroad has been analyzed.First, the micro-feed composition and the working principle are analyzed. The mechanism is driven by the piezoelectric actuator, ball screw drive, aerostatic guide supported by micro-institutions. Then the equivalent model of the part of transfer mechanism is established and the transfer function is given. Finally, preparing for simulation analysis, the transfer function of the entire experimental system is built.Second, according to the characteristics of a test table, fuzzy control system is designed. The system uses two-dimensional input, and uneven division in selecting the fuzzy membership function variables. In order to enhance gradual stability of system, low resolution fuzzy sets are adopted in the zone of larger error and higher-resolution fuzzy sets in the zone of smaller error. Simulation analysis found only conventional fuzzy controller can not get the desired results, after analysis, eventually an integrated fuzzy controller is adopted to be good simulation results and an experiment to provide guidance control system is designed.Finally, the integral-fuzzy control model of the experimental system is established. The experimental system architecture, algorithms and composition are introduced in detail. The experimental study of the feed mechanism is made. Comparing the experimental and simulation results shows better consistency, which provides the basis for micro-feed institutions application.