The Design And Research On The Vibration Measurement System By The Refelective Intensity-Modulated Fiber

The fiber vibration measurement sensor combining optical fiber sensing technology and vibration measurement technology, has many benefits, which is superior to the traditional vibration measurement technology, such as simple structure, small size, light weight, transmission security, strong resistance to electromagnetic interference etc, is able to fulfill the non-contact vibration measurement with high precision and high sensitivity in adverse environment. In the fiber vibration measurement system, vibration information is transmitted into the computer through A/D, is done with and analyzed fully in the computer. The system fulfills the integration of the vibration measurement and analysis, and the vibration measurement technology integration, has great significance on the Commercialization process of the optical fiber sensing technology, is one of the development direction of the optical fiber sensor in the future.The vibration measurement system by the reflective intensity-modulated fiber is designed .In the paper, the illumination specialties of a couple of fibers by accurate Gaussian distribution theory, Pre-signal conditioning circuit, signal post-processing and experimentations to testing the sensor's capacities are analyzed and researched.Firstly, referring and summing up the achievement of optical fiber sensor, the purpose and meaning of the vibration measurement system by the reflective intensity-modulated fiber is expatiated in the paper.Secondly, the principle of the reflective intensity-modulated fiber sensor and the assumptions of optical fiber intensity distribution at launching fiber end is described, the mathematical model of light reception power by a couple of fibers is formed, the influence of fiber structure parameters on light reception power is analyzed by use of LABVIEW and VB software to build the simulation system; kinds of detectors' response characteristics is analyzed after the mathematical model of detectors is built.Followed, the reflective intensity-modulated fiber sensor to measuring vibration is designed, emphasizing the fiber structures, the principle of fiber transmission, fiber types and characteristics, source selection and drive, Photodetector selection and so on.In succession, the pre-signal conditioning circuit is designed. In the circuit, the gain, bandwidth, relative error and noise are analyzed, integrated operational amplifier and other components are determined.Later, signal post-processing in LABVIEW software is described. Programs design, including Waveform acquisition, digital filter, window function, curve fitting and FRF, are emphasized.Finally, the sensor's capacities are experimented to testing and quantitative analysis, the improvement program for the capacities of the sensor is put forward after the influencing factors are measured,...