Development Of Thermal Conductivity Measuring Instrument Based On A Parameter Self-tuning Fuzzy PID Controller

Thermal conductivity is a very important parameter of the material. It is very common situation that the heat conducts from one body to the other. So it is very important to accurately measure the thermal conductivity of a material. Generically, there are two experimental methods to measure the thermal conductivity: the static method and the dynamic method. In static method, the thermal conductivity is measured when a thermal balance is reached, while in the dynamic method, the thermal balance is not required. The double-guarded-plate measurement method, which is used in our instrument, belongs to the static method. The thermal line measurement method, the thermal probe measurement method and the laser pulse measurement method belong to the dynamic method.In this paper, based on Fourier thermal conduction theory and a pre-developed thermal conductivity measuring instrument is optimized and tested. The mechanical part of the instrument is a double-guarded-plate structure, while its electronic part, including control module, data collection module, result display and print-out, is based on ARM(Advanced RISC Machines) microprocessor. The instrument has many advantages, such as high degree of automation, a user friendly interface, short measuring time, high precision and small volume.The main work of the thesis includes the following five aspects:1. Description and analysis of the Fourier one-dimensional steady-state thermal conduction theory;2. To analyze the theory of PID controller and the drawbacks of the old PID controller; Develop the parameter self—tuning fuzzy PID controller in order to solve the problem of the old PID controller.3. debug the system and design software. The work includes the time program, AD program, DA program, LCD and keyboard program, the parameter self-tuning fuzzy PID controller program.4. according to the experimentation of the old PID controller, analyze the problem of the instrument , find the main factor who affects the result and develop the new way to solve it.5. use the result of the new controller to compare the old result. Develop the measure precision.