Study On Online Controlling And Measuring System Of Temperature And Carbon Potential Infiltrating-carbon Furnace Based On Fuzzy Algorithm

Heat treatment is one important process for metal material process technics. It not only can ensure and enhance the quality and service life of metal parts but also can exert potential characteristic of metal materials. It is also a powerful method for conservation of raw materials. Along with Chinese industrial technology development, higher requirements are put forward for the heat treatment industry. On the basis of fuzzy algorithm, deep studies were conducted on the carburizing furnace temperature and carbon potential on-line measurement and control system. The main research contents and the results are as follows:According to the characteristics of carburizing furnace, such as its nonlinearity, time-variance and lagging characteristic, a model was set up for the temperature control system and carbon potential control system of carburizing furnace. A simulation was achieved for the system by utilizing MATLAB toolbox and Simulink simulation component-package. The result indicates that the big overshoot and long adjusting time exists under the PID control system,the overshoot gets bigger as shorter adjusting time,whereas the adjusting time turns longer if reduce overshoot. It also shows that satisfactory dynamic feature can be achieved for the system by using the method of fuzzy control, but the quiet error could not be eliminated. However, the fuzzy self-adaptive PID control not only has the features such as small amount duration of response, non-overshoot and better stability for the system but also has the feature of strong capability to resist signal disturbance.A hardware circuit was designed with the core of DSPLF2407. A monobus transmission digital sensor DS18B20 was selected for temperature compensating circuit which could transfer data with DSPLF2407 directly and dramatically simplified the design of circuit. The furnace temperature and carbon potential was controlled by bi-directional triode thyristor and solid state relay in the output controlled circuit.The popular modular approach was applied to design the system software including the main program flow and the various sub-module processes. Some numerical programs for partial sub-module were also listed below.