Aiming at the time-varying, large hysteresis and non-linear characteristics of powder metallurgy vacuum sintering furnace, the PID control effect is not ideal, and the fuzzy control algorithm is selected. The PID control and fuzzy control simulation models are established and compared. The results show that after fuzzy control, the system response speed is very fast, the steady state time is only 3.2s, there is no overshoot, and the steady state error is 1.2°C. The steady-state accuracy is very high; the system simulation output is close to the given input waveform, the system adjustment time is short, and the steady state is quickly entered, and the oscillation is very small. Fuzzy control is superior to traditional PID control and can meet the control requirements of powder metallurgy vacuum sintering furnace temperature.
The powder metallurgy vacuum sintering furnace is a time-varying, large-lag, nonlinear heating system. Due to its physical and chemical complexity, there are many influencing factors, and it is difficult to obtain accurate mathematical models. When the parameter changes greatly and the control precision is high, the general PID control effect is difficult to be satisfactory. Fuzzy control does not require the system to give an accurate mathematical model, formulate control rules based on human experience, make control decision tables, and control the system according to the decision table, which is especially suitable for complex industrial production objects such as sintering furnaces. The main factors affecting the quality of the product during sintering are sintering temperature and sintering time. The temperature requirements are very harsh. The temperature difference is generally not allowed to exceed ±3 °C~5 °C of the given value, so it must be strictly controlled [1~3] .