Research Of A Differential-Pressure And Cubage Compensation Leak Detection System Based On Fuzzy-PID Control

As a significant procedure in producing process of sealing parts, leak detection method has a direct impact on the indices of sealing property and even the performance of the whole system. The application of differential-pressure detection is widespread in micro-leak detection. Cubage compensation leak detection based on the differential-pressure is proposed, which offer important advantages including higher accuracy, shorter detection time and simpler calculation method of leak rate compared to ordinary differential-pressure method.The parameters of the system will be changed with various pressures, different tested parts and environment diversification in pressure balancing control based on cubage compensation. Nevertheless, the parameters of conventional PID control are usually adjusted in a particular case and can hardly adapt to various working conditions. Aiming to this, the paper researched and developed a differential-pressure and cubage compensation leak detection system based on optimized fuzzy-pid control, which can adapt to changs of the system parameters.This thesis elaborates the theory and design method the Fuzzy-PID control first, and designs the conventional Fuzzy-PID controller in detail, then introduces the adaptive set-point weighting to Fuzzy-PID control at the basis of simulation, and optimize the conventional Fuzzy-PID controller. The simulation results show that the optimized Fuzzy-PID controller is effective in inhibiting the process overshoot while maintaining other performance indices well. Subsequently, a method based on cubage compensation with differential-pressure is put forward, the process of detection system is explained in detail, and the hardware platform of differential-pressure leak detection system is implemented successfully. Then, Fuzzy-PID is utilized as control method for cubage compensation according to system requirements, the control software of detection system is designed. Finally, experiments are carried out with relevant equipments, the optimized algorithm based on Fuzzy-PID is authenticate to various pressures and tested parts. The optimized Fuzzy-PID control is validated to have better control performance in comparison with conventional PID control, and can still maintain a good quality with the changing of system parameters.