Design and Optimization of Integrated Controller for Vacuum Sintering Furnace

Integrated control of temperature and vacuum are demanded in cemented carbide vacuum sintering process. Because the dynamic characteristic of the vacuum sintering furnace temperature control object model has the specialties of non-linear, variable time delay and asymmetry, the conventional control methods can not achieve approving control results. The control core of the integrated controller is the microcontroller C8051F020. Fuzzy-PID temperature control based on control-action compensation methods is used. Aiming at parameter design of the fuzzy controller, the adjusting factors are used in every temperature error grade, the fuzzy control rules with the adjusting factors is formed. The scale factor decrease with increase of the furnace temperature. Particle swarm optimization (PSO) algorithm is used to tuning the adjusting factors, the quantization factors and the scale factor; automatically accomplish the fuzzy rules extraction. After the technical reform, the maximum overshoot of the temperature control from 60°C down to 20°C, the maximum track error down to 25°C.