Study on the Decoupling Control Strategy of the Airflow Temperature Control System

The airflow temperature control system adopts a dual-input single-output airflow temperature control structure and achieves accurate control of the airflow temperature signal through the direct mixing of cold and hot airflows. Based on the mathematical model of the system, four control strategies are proposed based on the system characteristics, such as fixing hot air flow rate/regulating cold air flow rate, fixing cold air flow rate/regulating hot air flow rate, linear proportional distributed regulation of cold and hot airflow, and nonlinear decoupling distributed regulation of cold and hot airflow. The simulation model is built based on MATLAB/Simulink, and the simulation results show that the system has the problems of slow response, large overshoot, and asymmetric temperature rise and fall process when only the cold air flow or hot air flow is adjusted. Both linear proportional and nonlinear decoupling control strategies can effectively improve the temperature dynamic response and reduce the asymmetry of the temperature rise and fall process to a certain extent, and the nonlinear decoupling control strategy of cold/hot airflow is better. This paper has implications for the control of similar dual-input single-output systems.