基于继电辨识法的医用恒温箱温度自适应控制

Thermostat Temperature Adaptive Control Based on Relay Feedback Identification

医用恒温箱的温度调节具有大时间常数、大惯性及时变特性,实际应用中难以用阶跃辨识法快速辨识其模型以及使用常规控制器进行有效控制。继电反馈辨识法不需要过程达到稳态即可快速辨识过程模型,自适应控制可以针对以上模型进行有效控制。提出了一种使用继电反馈辨识法进行恒温箱温度调节过程的辨识模型方法,并且利用该辨识模型设计了自适应控制器的控制器参数初值及控制律的方法;以瑞萨公司的C2B8SNFA为主控器,开发了恒温箱温度自适应调节器。实验结果验证了本文方法的可行性和有效性。

Thermostat has been widely applied to drugs, textiles, food processing and other fields. However, because there is a relatively large time lag of the temperature measurement and coupled with a time-varying and large time constant for temperature control in thermostat, the temperature precise regulation in thermostat is a challenge problem. Regular control methods such as IMC-PID can not perform very well. Till now, most of the modern control strategies are model-based and system identification methods are widely applied to get the plant model. However, in view of the time delay and large time constant features of thermostat regulation, the stability time of the step response is too long to carry out the step response identification. Because of the limits of safe operation, it is also difficult to apply the identification methods based on the pseudo random signal to the real operation. To identify the process model rapidly and satisfy the limits of safe operation, the relay feedback identification method is applied in this work. By applying the adaptive control, large inertia and time-variant can be overcome. The initial value of the adaptive controller parameter affects the overall control effect. It is necessary to design the initial value of the adaptive control parameter. In this work, a model identification method for temperature control of the thermostat with relay feedback identification is proposed. Based on the identified model, an adaptive controller is designed and the initial parameter of adaptive controller is optimized via solving linear martix inequality （LMI） with robust control method. The proposed method is applied to develop a temperature regulator based on C2B8SNFA MCU （Micro Controller Unit） for thermostat. The real application results verify the feasibility and effectiveness of the proposed method and the developed temperature regulator for the thermostat.