Vibration Characteristic Research Of Optical Fiber Gyro Based On The Underground Pipeline Trajectory Measuring System

Inertial navigation measurement technology is the important foundation of trenchless technology. But influenced by the factors of geology, stratum condition, pipeline depth etc., the trajectory of most underground pipeline measurement is difficult to calibrate with little accuracy. In order to satisfy the engineering accuracy demands of No-Dig, it is urgent to optimize the existing technology. Fiber optic gyroscope(FOG), one of the most important carrier trajectory detection sensors, is the foundation of the whole hardware system of underground pipeline trajectory measurement system. The whole underground pipeline trajectory measurement system is introduced: the computer technology, sensor technology, modern digital signal processing technology and communication technology, which can realize the underground pipeline trajectory measurement. But restricted by the internal mechanical design, the actual vibration can largely influence on the precision of fiber optic gyroscope measurement. This paper was focused on the simulation test environment, which was used to study the effect of vibration on fiber optic gyro, and then found out the key factors that affect the precision of fiber optic gyroscope. Further, the wolf pack algorithm was used to reduce or eliminate the influence of vibration on measurement precision fiber optic gyroscope.Based on the important sensor fiber optic gyro, the underground pipeline working principle of trajectory measurement system was deeply analyzed. The whole trajectory measurement system can be divided into mechanical system, software system and control system. This paper discussed the trajectory measurement system that can accomplish the measurement of completion pipe with the proper diameter size, and complete line of 3D trajectory detection. Then simulation experiment was designed, and completed the vibration experiments in different directions. The specific work in this paper was as follows:(1) Basic parameters of fiber optic gyroscope were introduced, including its basic principle of work, as well as the basic characteristics of inertial navigation system. On this basis, the function of measurement system, and the precision of the possible error sources were given;(2) The hardware part of the trajectory measuring system was optimized, and the body of mechanical system design was completed. According to the requirements of the system test function, the overall scheme of mechanical system was designed. And three claws marching round structure was introduced, as well as the selection of the encoder and functions. After the completion of the hardware assembly design, integrated debugging has been done.(3) Based on the software function of measurement system to be completed, the software part of the system was finished. The basic steps in the process design were introduced according to the lower machine programming, including data acquisition module, data processing module, and image module based on the script file in Matlab. Finally, the whole trajectory measurement system has been undergone integrated debugging on the calibration platform, which can make the best use of fiber optic gyroscope.(4) Based on the theory of vibration, simulation experiment has been tested on the specific measurement environment within the pipeline. Use random vibration model to do vibration experiment on the X, Y, Z axis in three different directions, and analyze the effect of vibration on optical fiber error. Finally, use wolf pack algorithm to carry out the vibration error compensation, and get a good compensation effect.