Research On Horizontal Directional Drilling Guidance Technology Based On Ground Magnetic Beacon

Horizontal directional drilling technology is one of the fastest-growing engineering technologies in recent years,and it occupies an important position in the field of trenchless technology.In the long horizontal directional drilling construction,due to various influences,the actual trajectory often deviates from the preset trajectory.This problem requires real-time steering and positioning of the bottom hole position during drilling.The current mainstream guidance positioning methods include walking tracking wireless navigation systems and grid wire frame control systems.These methods have high requirements on the construction environment and are expensive.This paper proposes a position measurement algorithm based on ground magnetic beacon and an attitude measurement algorithm based on Kalman fusion for the horizontal directional drilling steering positioning technology.This method has low requirements for site construction and high positioning accuracy.This paper has carried out systematic research on this method,and carried out simulation and experimental verification,mainly carried out the following research work:(1)This paper has deeply investigated the domestic and foreign horizontal directional drilling steering positioning technology,summarized the relevant elements describing the steering positioning technology,and studied the spatial coordinate conversion method based on Euler’s theorem.(2)A positioning method for horizontal directional drilling based on ground magnetic beacon is proposed.The magnetic field gradient tensor of the ground magnetic beacon is calculated by the measurement array installed on the bottom hole,and the position coordinates of the bottom hole are obtained.A measurement method based on the third-order magnetic gradient tensor and a measurement method based on differential processing are proposed to eliminate the influence of the geomagnetic field in the actual measurement.(3)The third-order magnetic gradient tensor measurement algorithm is studied through numerical simulation.The simulation results show that the experimental error measured by this method meets the requirements;the third-order magnetic gradient tensor measurement algorithm and the differential processing measurement algorithm are verified through experiments.The effectiveness of the two improved methods,according to experiments,the error of the third-order magnetic gradient tensor measurement method is smaller.(4)This paper utilizes the gyroscope,accelerometer and magnetometer of the strapdown drill at the bottom to measure the attitude.The accelerometer and magnetometer are used to measure the initial attitude,and an azimuth correction method under the influence of the environmental magnetic field is proposed.Three sets of experiments are carried out to verify the effectiveness of the algorithm.After that the error compensation is performed on the data during continuous attitude measurement,the optimal attitude angle is obtained through Kalman fusion,and the proposed fusion algorithm is verified through 3 sets of experiments,and the expected effect is achieved.(5)This paper designs and manufacture ground magnetic beacons,and conduct position measurement experiments with multiple sets of data.The position coordinates are calculated through the positioning algorithm,which verifies the feasibility of the algorithm.The Wi Fi crawler robot is used to simulate continuous drilling,and the optimal estimated angle obtained after that Kalman fusion is close to the actual value,which further shows that the calculation accuracy of the inclination angle,tool face angle and azimuth angle have been improved.