Research Of Laser Diode Temperature Control System Based On Smith Fuzzy Pid Optimized By Genetic Algorithm

LD is widely applied in all kinds of fields. For example, there are optical fiber communications, laser printers, high-resolution laser TV and others in industrial production and technology, laser surgery, laser treatment and life science research in medical treatment and life sciences and research on military applications such as laser fuse, laser guidance, laser diode. Temperature exerts powerful influence on LD' s threshold current, output power and the wavelength. Hence, when temperature is above 100 k, the threshold value grows at the rate of three cube along with T. It is necessary to design a set of LD temperature control system with high accuracy, good stability low price.The paper designs a set of LD temperature control system based on ARM micro-controller. Because of the complexity of the process of heating and cooling and heat conduction rate of temperature detection device structure, the controlled object is compelled to delay time and nonlinear. Thus, the paper has put forward a a fuzzy adaptive PID – Smith with the combination of genetic algorithm to utilize MATLAB simulation software and make a comparison between traditional PID algorithm and fuzzy adaptive PID algorithm. Through the simulation, the conclusion can be made that fuzzy adaptive PID – Smith is characterized with a small excess, adjusting the time, high control accuracy, which can adjust the controller parameters online with the estimation of Smith.The temperature control system consists of two parts, hardware circuit design and software design. Hardware is designed with Altium Designer software for schematic and PCB. It has a integrated analysis function before layout and after the layout, using the signal integrated analyzer to get the accurate the simulation results. Using ST' s STM32F103RCT6 as control core of circuit main and PT100 platinum as temperature sensing element, TEC software, thermoelectric refrigerating unit as hot electric refrigerator and Real View MDK5 as development platform downloads via a serial port and set aside a serial port line for update and improvement. By analyzing the whole control system's test and performance, the test result demonstrates that system's temperature control accuracy is 0.1 degrees and temperature control ranges from 10 degrees to 50 degrees.The LD temperature control system designed by the paper is not only featured with high accuracy and simple frame, low coupling between models and low cost and but also it is convenient for updating and maintenance and satisfies requirement of control.