Control system of single-crystal growth with an invariable diameter based on parameter self-adjusting fuzzy control

Automatic diameter control (ADC) is an important procedure in the Czochralski pulling. Crystal growth control system with an invariable diameter lacks a precise mathematical model, and has nonlinear and time-varying characteristics. For tacking above problems, fuzzy control strategy has been proposed in this paper. To enhance control accuracy and disturbance resisting ability, fuzzy-PI controller for the parameter self-adjusting has been adopted in this system. The results of experiment show that this controller can make the warp unwinding tension be automatically-controlled efficiently, and has higher control accuracy, better disturbance-resisting ability, less sensitive to parameter changes, and better robustness.