Research Of Micro Displacement Test System Based On Capacitive Grille

With the continuous development of weapons and equipment,cutting-edge equipment and machinery manufacturing in China,the intermal structure of precision machinery is becoming more and more complex,which puts forward higher requirements for the technical means of small displacement measurement.The small displacement of components needs to be quickly detected by detecting the operating state of equipment and controlling the precision docking process inside the precision equipment and complex structures.The detection of small displacement is of great significance in the fields of precision machinery,automatic control,weapon equipment,and many physical quantities such as acceleration,pressure,strain and so on can be measured indirectly by measuring small displacement.At present,many sensors can achieve high precision in measurement,but there are disadvantages of large volume and poor stability.The capacitive grille is thin in thickness,small in size,high in precision and strong in anti-jamming ability,so this paper puts forward a small displacement test system based on capacitive grille sensor for the test environment with very narrow test space(<lmm),complex test environment and electromagnetic interference.The test system can carry out the displacement test in two dimension,improve the integration of the sensor and reduce the complexity of the system.The design of the differential amplifier circuit not only solves the problem which the nonlinear variation of the capacitance of the capacitive grille leads to the small test range,but also eliminates the eommon-mode interferenee in the system and improves the test accuracy.The test system completes the detection,amplification,sampling and storage of the weak output signal of the capacitive grille,and the computer software processes,filters,calibrates and displays the measurement results of the test data.On the basis of the design of the test system,the following work has also been carried out:(1)Combining with the characteristics and working condition of the capacitive grille sensor,the structure design is carried out,the parameter optimization design is carried out based on the edge effect and finite element simulation of the capacitive grille,the edge effect elimination measures are put forward,and the feasibility of the those measures is verified by simulation.(2)Maxwell simulation of the working environnent of the capacitive grille is carried out,and the feasibility and system output characteristics of the two-dimensional displacement of the capacitive grille are analyzed,as well as the working characteristics of the capacitive grille in the cylindrical and spherical environment.(3)The test system is tested by the measured data,the test system is calibrated,the improvement measures are put forward according to the problems in the debugging proeess,and the anti-jamming measures are put forward for the interference factors in the test system.