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The Theory And Design For Resonant Sensor

Posted on:2005-09-01Degree:MasterType:Thesis
Country:ChinaCandidate:M ZhouFull Text:PDF
GTID:2168360152969059Subject:Detection Technology and Automation
Abstract/Summary:PDF Full Text Request
Resonant sensor system is a kind of quasi-digital measuring device utilizing the effect that the natural frequency of the resonator changes according to the measured frequency. Its major key technique is to constitute a high quality electromechanical close-loop resonant system with mechanical resonator using positive feedback principle. This thesis mainly discusses and studies the resonant characteristics of the mechanical resonance, modeling of the electromechanical resonant system and its close-loop stability in depth. Mechanical resonance is the core component of the resonant sensor system. Starting from resonant theory and based on electromechanical analogy, this thesis introduces the concepts of speed impedance and mobility as well as the electrical analyzing methods. It provides universal descriptions to the damping characteristics,dynamic characteristics, phase-amplitude relation and internal energy conversion of the resonator. Then by comparing and analyzing the phase-amplitude characteristics of the resonator in resonant state of displacement, velocity and acceleration, it shows that the close-loop resonant system with velocity signal feedback has the best resonant characteristics. In order to analyze the influence the excitation circuit and pick-up circuit exerting on the resonator, the equivalent circuit model for the resonant sensor system is established, then the electromechanical decoupling design principle of using the constant-current source and high input-impendence amplifier as collector is obtained through electromechanical analysis. Based on the prerequisite of system resonance, this thesis obtains the sufficient condition of system stability using quasi-linear theory and brings forward the criterions of the system stability. Finally, according to the conclusions drawn, a resonant sensor system is designed and its stability is evaluated.
Keywords/Search Tags:Resonant sensor, resonant characteristics, electromechanical analogy, stability
PDF Full Text Request
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