Objective: To establish the mathematical model of human skin temperature changes under the infrared physiotherapy apparatus. To design the fuzzy PID controller based on the mathematical model.
Method: The skin of the back was irradiated by an infrared physiotherapy apparatus. The skin temperature data from an initial steady state to a new steady state was measured, recorded and analyzed. With the MATLAB software’s help, mathematical models of human skin temperature changes under infrared irradiation were established using the curve fitting method. Fuzzy PID controller was designed with METLAB Fuzzy Logic and Simulink toolbox based on the mathematical model.
Result and Conclusion: The mathematical model of human body irradiated by infrared physiotherapy apparatus is second-order plants with time delay. Under the control of fuzzy PID controller, the system is more stable and more secure.