A Study On The Key Techniques Of Intellegent Capacitance Micrometer System

As a method of non-contact micro-displacement measurement,the high accuracycapacitance micrometer has many advantages such as high temperature stability,widemeasuring range,high accuracy,high resolution,good dynamic response and simplestructure, etc. In recent years this kind of instrument is widely used by aerospace andindustry departments to measure micro displacements,micro sizes and vibrations andmany others.With the rapid development of science technology and industry,people requirehigher and higher resolution, accuracy and stability. As a means of noncontactmeasurement,JDC series of capacitance measuring technologies utilize early periodelectronic elements. These elements are not good enough in accuracy and reliability.The analog circuits are quite complicated and difficult to debug. There is a lot workneeded to make them intelligent, miniature and good in function. The research workin this thesis is focused at solving these problems.The development of capacitance micrometer technology is reviewed and itsworking principle and key techniques are extensively analyzed in the thesis. A newminiature and intelligent capacitance-micrometer scheme based on MCU-C8051F060is presented. Related technologies in the design of capacitance sensors are discussed.The main circuits including driving cable amplifier, precise rectifier and filter arestudied. The stability of the amplitude frequency characteristic is analyzed and thecircuit performance is optimized by using automatic control theory. A new design ofhighly accurate and steady sine-wave source based on Digital Synthesized Techniqueis put forward. The system can realize data acquisition, filtering, and parameter setupby keyboard, digital display, storage, print and communication with a PC via a serialport. The measurement uncertainty is analyzed theoretically and some experiments fortesting the performance of the measuring system have been carried out.