A Study Of Micro Capacitive Pressure Measurement System Based On Optical Trigger

The pressure in bore contains the information of guns and ammunition. By efficient acquiring the chamber pressure information, researchers can improve weapons and ammunition, which make it more in line with the needs of modern national defense development. The last generation of pressure measurement has high precision, but the cost is high. For this purpose, a new generation of pressure measuring device based on the capacitance sensing of the shell is put forward through the theoretical demonstration. At present, the construction of the pressure field in gun bore is lack of the measured data of multi-point pressure. And carrying out multi- point test need trigger signal. The development of light triggered capacitive pressure measuring device uses special light window to receive the optical signal by the internal photoelectric device. At the same time, the optical window of capacitive pressure measuring device will bring the problem of electromagnetic shielding and protection.To this end, this paper has done the following work:(1) The factors affecting the operation and precision of the capacitive sensor are analyzed. The mechanism of the effect of edge effect on capacitance and the method to reduce the effect are also analyzed.(2) The study of light triggered pressure measuring device is carried out. The electromagnetic shielding is required after the optical trigger pressure measuring device is opened, thereby reducing the influence of the external electromagnetic field on the internal circuit of the pressure measuring device including the optical trigger circuit. A variety of electromagnetic shielding materials were analyzed, and the structure of light window with light transmission and electromagnetic shielding was designed,and introduces a pre-stage multiple light guide means. The wireless charging technology is explored and analyzed.(3) The structure of each module circuit is analyzed, and the advantages and disadvantages of three kinds of signal conditioning circuits are analyzed. In order to adapt to the design requirements of the pressure measuring device, the host computer software is redesigned.(4) The experiment prototype was developed, and the experiment data were obtained. The test data are analyzed, finding the existence of problems such as temperature drift, the test curve baseline drift, and proposes a preliminary solution.