The Research Of A New Type Capacitance Sensor Used In The Measurement Of Small Displacement

In this thesis a new type capacitance sensor was designed. Used it could detect the small displacement of some object. Compared with the traditional structure the new pattern had the two board of the detect capacitance installed the same side.And the same time had two board of the fix quantity capacitance installed the other side of the plane. It had simple structure, so it is very convenient installed online.Equiped with the high precision detective circuit and the microcontroller, this meter realized intelligentize, and it not only can realize many noncontact measurement in high definition and efficiency but also can be easy to fulfill some automatic demands like dynamic sampling real time processing on-line measuring. So it will be well used in the modern industry measurement and has a wide prospect in the future.In this paper firstly discussed the structure of the traditional capacitance sensor and on the base bring forward a new type structure of the capacitance sensor. Used the electromagnetism theory analyzed the principle of the measurement of the small displacement, and by experiment established the mathematical model about the change quantity of the small displacement and the change quantity of the capacitance sensor. Through decected the change of the capacitance acquired the change quantity of the small displacement. The emphasis in experiment was the study of stability of the circuit ,and ultimately make a breakthrough progress.The meter adopts AT89C51 microcontroller to fulfill intelligentized requirementand the theme had introduced the structure of system hardware and software, fashioned a prototype model. Used the model carried out many times measurement of the small displacement, analysed and discussed the data. The result of the instrument achieved the established requirement. The theme also give a presentation of the precision variety influenced by the different work condition.In a word, this paper has achieved the design requirement and made a newfashioned single-piece capacitance sensor and a small displacement measurement system both in theory and practice, and expectant target of design has been fulfilled.