The Development And Realization Of Vibration Detecting System Based On FBG Sensor

Vibration test is playing more and more important role in modern engineering field.At present,the main method of vibration measurement with mechanical measurement,electrical measurement,optical measurement,the electrical sensor because of mature technology,the advantages of high sensitivity and is widely used,but this kind of sensor needs to be insulated,and susceptible to electromagnetic interference,which seriously restrict the development of vibration test technology.Fiber grating sensor has the advantages of small volume,light texture,transmission distance,dynamic measurement range,and strong magnetic interference,strong power,high temperature and other harsh environment,so the vibration testing technology and optical fiber sensing technology,design and development of a vibration sensor detection system based on FBG.The system takes vibration signal measurement as the starting point,and designs FBG vibration sensor,vibration demodulation system and host computer software.The main research contents and results are as follows:Firstly,the FBG sensing theory is deeply analyzed,and the FBG vibration sensor based on flexure hinge structure is designed.The sensor is composed of pedestal,mass block,flexible hinge and fiber Prague grating(FBG),and the structure is integrated.The fiber Prague grating with a certain prestress is pasted between the mass block and the base.As the sensing probe of the vibration system,the magnitude of the vibration signal is detected through the variation of the central wavelength.In the process of making sensors,the optimum structure parameters are designed,and the natural frequencies of the sensors are simulated and analyzed by SolidWorks.Then,through the analysis and comparison of the volume phase grating wavelength demodulation method of transmission based on the fiber grating demodulation module FBGA with high sensitivity and high precision BaySpec production company,designed and assembled the high-speed demodulation system.In the relatively complex and harsh environment detected due to change of the physical quantity to be measured by the light changes,realize the measurement of fiber grating sensor wavelength precisely and quickly,meet the vibration detection field in the sampling precision,size and other aspects of the demand,sampling rate.Then,according to the system functional and non functional requirements and performance indicators,the overall design scheme of software system matching with FBGA demodulation equipment,realize the system modeling through UML case diagram and use case specification.The visualization program development tool Visual Studio 2010,MFC multi document based programming,using C++programming language,USB communication and multi thread and dynamic link library technology to realize vibration signal acquisition,processing,display and storage function.Among them,the two core modules of data acquisition and data processing increase the fault-tolerant mechanism of the system,and optimize the system performance.It is embodied in the judgment of the number of peaks and the rationality of data,the method of mean filtering,and the processing of burr data.In addition,the modeling and implementation of the database SQL,Server are emphasized,and the parameter configuration tables,sensor information tables and data tables in the database are introduced in detail.Finally,an experimental system to test the performance of the vibration detection system,through the FBGA demodulation equipment and computer software to realize data acquisition,display and storage work of vibration sensor based on flexure hinges,analyze and deal with the experimental data,verify the PC software and the performance of demodulation system at the same time,also verified the performance of the sensor.The experimental results show that the vibration detection system can be used for real-time detection of the vibration signal,timely and accurate grasp of the situation of engineering structure,against vibration mitigation,ensure the engineering safety system has the important meaning and value.