Research On Intelligent Temperature Control Method For Infrared Drying Box Of Grain Moisture Tester

As an important component of moisture analyzer based on mass loss on drying method,infrared drying oven has been a research hotspot in the field of instrument manufacturing at home and abroad because of its small size and complex space structure.In this thesis,HC103 moisture analyzer as the research object,through the particle swarm parameter identification method to establish the mathematical model of temperature control system,and finally put forward a variable universe fuzzy PID temperature control method,in order to achieve the purpose of drying heating temperature rise smoothly and have high temperature control accuracy when measuring the moisture content of samples.By analyzing the structure and working principle of infrared drying oven of HC103 moisture analyzer,the transfer function model of generalized temperature control system of infrared drying oven is established by theoretical analysis.According to the temperature test data of the infrared drying oven in the actual drying and heating process,the least square method and particle swarm optimization algorithm are used to identify the parameters of the generalized temperature control system model,and a more accurate mathematical model is obtained,which lays the foundation for the design of temperature control methods.On the basis of the introduction of the stretching factor α(x)and β(x)and the optimization mechanism of the variable domain which makes the fuzzy cybernetics domain adaptively adjust with the change of output temperature error,the structure of variable domain fuzzy PID temperature control system is designed,and the simulation model of infrared drying oven temperature control system is built in the MATLAB/Simulink simulation experimental platform,when the working temperature of the drying oven is set to 60℃,80℃,105℃ and 130℃,the overshoot is less than 5%,the maximum dynamic error is less than 5℃ and the steady-state error is less than 0.5℃.It is proved that the proposed variable domain fuzzy PID temperature control method has good control effect.Meanwhile,in order to verify the correctness and feasibility of variable theory domain fuzzy PID control in temperature control of infrared drying oven,a numerical simulation model of temperature field of infrared drying oven was built in ANSYS/FLUENT simulation platform.The numerical simulation results show that the drying and heating temperature of the infrared drying oven under the variable domain fuzzy PID control can rise rapidly and steadily and maintain uniform distribution after reaching the steady state,avoiding the phenomenon of scorch of the measured sample due to high temperature,and verifying the correctness and feasibility of the temperature control algorithm.