The Study Of Micro Miniature Capacitive Pressure Test Device

Nowadays, each country increases their input into military affairs, and the technology ofartillery of various calibers has rapid growth. China is also actively developing all kinds ofnew-type artilleries. However, chamber pressure measurement technology corresponding tothe artillery technology lags behind. The existing problems of Pressure-tested Device,including big volume and high costs, restrain the progressive development of China’s artillerytechnology. On the basis of the developed internal electronic Bore Pressure-tested Device bythis research group, capacitive sensor technology is applied to pressure test. The principle ofcapacitive sensor is used to put forward capacitive electronic Pressure-tested Device based onthe integration of sensing and shell. Characteristics of the shell of the Pressure-tested Deviceare directly utilized to design one cylindrical capacitive pressure sensor, reducing the cost ofsensor, decreasing the volume of Pressure-tested Device, symbolizing a new exploration andtrail on chamber pressure measurement technology.The principle and characteristics, static and dynamic characteristics of the capacitive sensorare introduced in this thesis. Firstly, I analyzed the structure design of the shell and ANSYSmechanical simulation results. Secondly, capacitance value of the coaxial cylindrical capacitoris calculated. Thirdly, influencing factors of capacitance measurement were analyzed. At last,feasibility study was carried out on these bases. At the same time, I designed the detection oftransient small capacitance with high sampling frequency, two constant current sources areused to charge and discharge the capacitors, then conversion amplification got shell from thepressure. The circuit, designed by differential direct charge method, used for detecting theshell capacitance completes detection and extraction the micro-capacitance signal, hasimplemented the function of pressure measurement. The inverter can reduce the nonlinearityerror with small volume, low power consumption, feature of high resolution and highsampling rate characteristics. Complete the measurement of pressure through the experiment, verify the feasibility oftesting instruments, it has extensive application value in small volume, low powerconsumption and low cost.