Design And Application Of Low-latency And Anti-interference Temperature Controller For Medical Equipment And Home Appliances

In the fields of home appliances,biomedicine and other fields,precise temperature control of the system is required.This type of temperature control system has the characteristics of large lags and multiple interferences,and the products have strict requirements on performance indicators,and have strict standards for reliability and consistency of controllers.Therefore,the design of the controller brings great challenges.According to the different characteristics and performance index requirements of cell incubators and instant water heaters,in order to achieve high-precision temperature control,a fuzzy PID controller with compensation mechanism and an improved LADRC-Smith controller were designed respectively.The specific research content is as follows:(1)Establish mathematical models of cell incubators and instant water heaters.A mathematical model of the cell incubator was established based on theoretical analysis,system identification,and physical machine test data.An experimental model of the door incubation temperature of the cell incubator was designed based on the MATLAB simulation platform,and then the simulation data was compared with the field data to verify the validity of the model.After analyzing the energy flow direction of the instant water heater,according to the law of conservation of energy,the model was established by the mechanism method.For the calculation of unknown parameters in the model,a closed-water temperature rise experiment was designed,and the approximate step response curve was fitted.Partial parameters K,T,andτ were obtained by the mapping method.The heating efficiency and heat loss coefficient were obtained by the inverse model,and the final model was obtained.(2)Aiming at the large inertia and high delay characteristics of the cell incubator,a fuzzy PID controller with compensation mechanism was designed.Based on the characteristics of the temperature control platform of the cell culture incubator and the debugging experience,a fuzzy rule table for temperature control is established.After the experimental comparison,the triangle membership function is finally selected for fuzzy inference,and the gravity center method is used to defuzzify the cell incubator.Finally,precise temperature control of cell incubator is realized.The project realizes no overshoot and no condensation,stable uniformity of ± 0.3,fluctuation of ± 0.2,and door opening temperature lower than 4min.It has good dynamic characteristics and steady-state performance.(3)Aiming at the problem of poor immunity of instant water heaters,based on the active disturbance rejection controller with disturbance estimation and the Smith estimator with compensation capability,the characteristics of the sy stem time delay link can be compensated.The ADRC-Smith controller is adopted to solve the output deviation from the set value problem.In view of the deviation between the estimated value of the Smith estimator and the actual output value,which causes the output value to fluctuate,an error feedback compensation link was introduced to achieve stable output,and an improved LADRC-Smith controller was designed.Based on the closed-water temperature rise experimental model of instantaneous water heaters and MATLAB simulation platform for simulation verification,the simulation results show that the improved LADRC-Smith controller solves the problem that the output deviates from the set value at the time of stability.The temperature control system of instant water heater with large hysteresis and strong interference can achieve stable and stable control,which has good robustness and dynamic property.In the instant water heater temperature control project,the anti-interference performance of the improved ADRC-Smith controller was verified through multi-scenario experiments.