Dissertation > Excellent graduate degree dissertation topics show

Application of Vibration Demodulation System Based on Optical Fiber Sensing Technology

Author: JiangYueKe
Tutor: SuiQingMei
School: Shandong University
Course: Detection Technology and Automation
Keywords: fiber Bragg grating coupler vibration demodulation photoelectric conversion
CLC: TN763
Type: Master's thesis
Year: 2009
Downloads: 286
Quote: 6
Read: Download Dissertation

Abstract


Since the 20th century, vibration examination technique has gotten a huge development. It has experienced three stages: mechanical, electricial, and optical measurement technology. Currently, the electricial vibration seneor is widely used because of its mature technique and high senstivity, but it need insulating process and it is affected by electromagnetism interference easily, so that the purpose of producting safely is difficult to achieve. In a word, on account of these disadvantages of electricial vibration seneors, their application in high-voltage, large magnetic field such as power plant, has a lot of limitation. At the same time, the fiber-optic sensing technology which has many advantages such as high senstivity, small size, light weight, essential safety, anti-electromagnetism interference and corrosion resistance etc, represent the development direction of novel sensors. Therefore, in this paper optical fiber sensing technology and vibration detection technology is connected together, and vibration demodulation system based on optical fiber sensing technology is developed.In this paper, the following several topics are mainly studied:1) Fiber Bragg grating sensor working principle was analysized in detail based on coupled-mode theory, and fiber Bragg grating temperature and strain model was founded. At the same time, a new FBG vibration sensor was designed and vibration testing system was set up to verify the performance of fiber grating sensor. The experimental results as follows: the inherent frequency of the fiber grating vibration sensor is 250Hz; at low-frequency from 10Hz to 120Hz, the vibration sensor has a better response; the sensor can detect the smallest vibration intensity up to 2 micrometer. All the parameters satisfy the requirements of the Fan Vibration Detecting System.2) From analysis of optical coupling phenomenon based on local coupled-mode theory of slowly variable non-formal waveguide, Mathematical relationship of oupling outputs, coupling length and variation of refractivethe index was enduced. After analysis of the effect of vabriation to oupling outputs was achieved, coupling low frequency fiber-optic vibration sensor and high frequency fiber-optic vibration sensor were designed separately using single-mode optical fiber coupler. In Compare experiment of low-frequency coupling fiber-optic vibration sensor and FBG vibration sensor, low-frequency coupling fiber-optic vibration sensor respones more quick than FBG vibration sensor to striking signal, while the FBG sensor has bigger damping and decay faster, but they agree with ench other to periodic signal of 30Hz-50Hz. In Compare experiment of high-frequency coupling fiber-optic vibration sensor andpiezoelectricity vibration sensor, amplitude of the fiber-optic couplers is bigger than that of andpiezoelectricity vibration sensor, while they agree with ench other to vabriation signal of 2 KHz to 6 KHz.3) An integrated fiber-optic vibration demodulation system was designed, and hardware design and software design were introduced in detaile. Actual circuit schematic diagrams for the hardware circuit design, from the chioce of the photodiode, front-end current-voltage conversion circuit, amplifier, to the peripheral devices of LPC2148 were given out and the and the attention of the design process was pointed out. In the process of designing software, it was introduced that the port process of theμC/OS-II real-time embedded operating system on LPC2148, the interruption design of the vibration system demodulation system inμC/OS-II system, as well as the procedures for the design of the functions of the various tasks and their interrelationships. Finally, the implementation of USB Communications between PC and demodulation system was explained.4) According to the theoretical analysis and experimental results of the study, the fiber Bragg grating sensor was trialed in Fan vibration detection project at 500,000 KW generating units in a Generating Company, and it has achieved the desired results.

Related Dissertations

  1. Research on the Method of Electromagnetic Induction Data Tansmission in Downhole,TE928
  2. Study on Theory and Experiment of Wire Drawing with Composite Ultrasonic Vibration,TG663
  3. Research on the 6-Dof Fault Tolerant Control of the Vibration Isolation Platform with Eight Actuators,TB535.1
  4. The Study of Control Algorithm for Automotive Power Window Based on Lin Bus,U463.6
  5. The Equivalent Circuit Model of Radial Vibration Mode Piezoelectric Transformer and Its Application,TM406
  6. Study of Synchronization and Adaptive Frequency in Frequency-Hopping System,TN914.41
  7. The Research and Realization of Medium Wave Receiver Based on Software Defined Radio,TN851
  8. Investigation of Fabrication, Characterization and Property of Fuctional Titanium Dioxide Nanoporous Materials,TB383.1
  9. Research on Structural Vibration of Steam Piping System,TK284.1
  10. Research of DSP-based Real-time Demodulation Method of One-frequency Laser Interferometer,TN911.3
  11. Closed thin-walled beams composite modal damping prediction,TB33
  12. Axial fan blade vibration non-contact measurement,TD441.2
  13. Design and Study of Rectangular Wave Filter and Beam Splitters Based on Photonic Crystals,TN713
  14. Research on Dispersion Compensation Technology Using Fiber Bragg Grating,TN929.1
  15. Research on Dynamic Characteristics of Rolling Main Drive System by Taking into Account of the Gear Variable Stiffness,TH113
  16. Optical Hilbert Transform Based on Fiber Bragg Gratings,TN253
  17. The Development of a New Portable Internal Combustion Blast Tamping Machine,U216.631
  18. On Attitude Control and Vibration Suppression of Flexible Spacecraft,V448.2
  19. Experimental Study on Dense Packing of Monosized and Binary Spherical Particles Subjected to Vibrations,O347.7
  20. The Basic Study on Semi-active Control of Damping Controlled to Serial Robot,TB535.1
  21. The Study of Vibration Signal Analysis System Based on Wavelet Fractal Theory,TN911.6

CLC: > Industrial Technology > Radio electronics, telecommunications technology > Basic electronic circuits > Modulation technique and the modulator,demodulator and the demodulator > Demodulation technique and demodulator
© 2012 www.DissertationTopic.Net  Mobile