| Networked control system(NCS) has the advantages of low cost etc, promoting its development. Meanwhile, it has the characteristics of the network induced delay etc, influencing the performance of the NCS, even affecting the stability of the system sometimes. The studies of NCS meet some challenges.Firstly, networked thermostat temperature control system is built. By analysing the working principle of the peltier effect, the semiconductor refrigeration device with heat dissipation has been designed, improving the refrigerating capacity of the plant. And the signal conditioning board is designed to meet the hardware requirements. Based on the provided C drive library files, Java Native Interface(JNI) library files are designed. At the same time, according to the HORB network communication platform, the software platform of networked control system is designed.Then by analyzing the principle of semiconductor refrigeration and thermostat structure based on the theory of thermodynamics equation, peltier’s model and thermostat’s model are established respectively. According to the network induced delay of experimental platform, establish the determine time delay network model between the PWM duty ratio input and the temperature output. At the same time, the model output following controller based on command generator tracker(CGT) is designed for networked thermostat temperature control system. The simulation and experimental results show that the controller is not suitable for the system with time-varying parameters.Finally, adaptive model output following control based on CGT is proposed. Utilizing the fading memory least-squares method to identificate of system parameters online and adjusting CGT tracking controller, the sytem keeps good tracking performance. For big inertia system such as temperature system, when the system parameters change, the controller can guarantee the system stability and tracking performance. Experimental results show the effectiveness of the controller. |
