The Study Of Fuzzy Control System About Soft Abrasive Flow Machining

In the process of the soft abrasive flow without tool precision machining, the temperature increases as the processing carried out gradually, leading to the change of the fluid viscosity of the abrasive flow, the change in viscosity leads to the unevenness of the surface of the workpiece machining of soft abrasive flow. To solve this problem, a method is proposed to adjust the flow rate through designing a set of fuzzy control system for soft abrasive flow machining, to compensate for the adverse effects caused by temperature changes, and to improve the processing uniformity of the workpiece surface. The main work of the subject is as follows:(1) Mathematical models of soft abrasive flow machining are built, which based on the theory of k-εturbulence model and mechanics of viscous fluid. The turbulent kinetic energy and dynamic pressure of the near-wall region of the workpiece surface are analyzed, based on the FLUENT software which simulates the flow of soft abrasive flow in DC Road. By the simulation comparison of different temperatures in the same flow rate, the impact of temperature changes on the turbulent kinetic energy and dynamic pressure distribution of the workpiece surface is analyzed, by simulation comparative of different flow rates through the same temperature, the impact of the flow rate on the turbulent kinetic energy and dynamic pressure distribution. Based on the comprehensive analysis of the previous simulation, making temperature-optimal speed curve, fitting the temperature-the optimum speed formula, which provide a theoretical basis for the the later flow rate regulation.(2)According to the characteristics of the soft abrasive flow machining, designing a fuzzy controller in the fuzzy control system for soft abrasive flow machining, which mainly include:the design of the structure of fuzzy controller, the choice of the input and output, the determination of the fuzzy theory domain, the selection of the fuzzy language variable, the designs of membership function and fuzzy control rules. Using MATLAB to simulate the fuzzy controller and fuzzy control system, and modifying and improving the design of fuzzy control based on the simulation results.(3) Designing the hardware and software for soft abrasive flow machining in the fuzzy control system, and building control platform and experimental platform. Experimental research of the soft abrasive flow velocity regulatory processing and the test of the control performance and the validation of processing effect were performed. Experimental results show that:by rate regulation, the uniformity of the workpiece to be machined greatly improved, which proves that the design of this article is effective and feasible.