Research On The Control System Of Pneumatic Loading Of Double-Sided Polishing Maching

The precise double-sided polishing process is one of the main methods to get the ultra-smooth surface of semiconductor material wafer,for the demand of the rapid development ofthe microelectronic and information technology. It is the research tendency t o get the smooth andnon-traumatic surface of the silicon wafer with high efficiency in the field of the ultra-precisionpolishing technology. In double-sided polishing machine,pneumatic loading system is require dto be able to precisely control the load superimposed on the workpiece,while the polishing isbeing undertaken.Pneumatic loading system is the very crucial part of the double-sided polishingmachine,the polishing machine's performances are directly determined by the loadingprecision. In this paper,the pneumatic loading system was modeled and simulated by AMESi mto research the loading characters,and the proper PID parameter was given.For realizing therequirement of hi gh precision and responsibility,the fuzzy self-tuning PID controller wasdesign by fuzzy box in MATLAB. T he fuzzy PID control algorithm was used in control system,and the PID parameter fuzzy look-up table was given. The fuzzy PID joint simulation of theAMESim and Simul i nk was r ealize d,and the simulation results were compared.For the whole requirements of the double-sided loading system,the overall functionand the overall program of control system were designed,which mainly consist of the controlsystem of double-sided pneumatic loading was developed; the selection of mainly parts,thedesign of hardware and software and the explanation of the important programs; the design ofhuman-machine interface.Finally,the experiments were carried out by the measuring the precise loading on th e workpiece and the quality of the surface finish. With the optimization of the PID parameters andresearch of loading characters,the precision polishing with ultra-smooth and non-traumaticsurface of wafer was achieved.