Research On Measurement And Tracking Method To Trajectory For Horizontal Drilling Machine In Mine

The dissertation is supported by Coal Based Low Carbon Joint Fund Project of Shanxi(U1510112)and Jinmei Group Scientific and Technological Breakthrough Project in 2014.This article mainly concerns the aspect that the real borehole trajectory of horizontal directional drilling can’t track the designed trajectory quickly and accurately.In the recent years,with the rapid development of coal bed gas industry in china,the application of horizontal directional drilling rig is becoming more and more extensive,the accuracy and rapidity of trajectory measurement and tracking directly impact the efficiency and safety of production.For many years,the horizontal directional drilling machine for mine has been relying on import,which seriously restricts the decelopment of coal bed gas industry due to the technical blockade,long spare parts and not timely service.Although many coal machinery enterprises in China have made great progress in developing horizontal drilling rig,the gap to the advanced foreign technology is still large in the aspect of measurment while drilling technology and trajectory tracking technology.Therefore,it is of great practical significance and great economic value to study the drilling trajectory measuring system and tracking technology of horizontal directional drilling rig with independent intellectual property rights and advanced international level.In this paper,the mining horizontal drilling rig(including horizontal kilometer directional drilling machine and general slewing drilling rig)is studied,and after the extensive research on the trajectory measurement technology and tracking technology at home and abroad,a self-developed measurement while drilling system is achieved for general mining slewing drilling rig.Then,the measurement technology,calibration strategy and anti-magnetic interferenc method,as well as trajectory tracking technology of horizontal kilometer directional drilling machine,have been further studied.The details are as follows:(1)The measurement while drilling system is an important part of horizontal drilling rig in coal mine,which is mainly used for measuring and plotting the borehole trajectory.In this paper,a method namely off-line data synchronization method is presented based on the function and technical requirements of mining general slewing drilling rig as well as the operation rules of coal mine site and drilling process.On the basis of this method,off-line measurement while drilling system is developed,which contains bottom attitude measurement unit(probe),orifice data synchronization unit(synchronizer)and trajectory analysis software.The system enables mining general slewing drilling rig to have the function of measuring and drawing borehole trajectory without changing the structure and drilling process.(2)Calibration of the attitude measurement unit is an important part for accurate trajectory mapping of measurement while drilling system.In this paper,the error source of sensor model(tri-axial accelerometer-tri-axial magnetometer-the carrier coordinate system)for measurement while drilling system is researched in depth as well as the existing basic calibration methods,especially the low cost calibration method without external reference,for the problem that the existing calibration methods are backward and high-cost,even exist defect points,and a combined calibration strategy for multi-vector sensors is proposed.This strategy achieve the goal of calibrating all the linear time invariant errors via combining the basic calibration mehtods,on the basis of solving the misalignment error between the sensor coordiante system and the carrier coordinate systmem and considering the data acquisiton method.By studying the relationship between the misalignment error angle angle and the attitude angle,this strategy also simplifies the calibration process,improves the robustness and makes the result more true and accurate.(3)It is very important to exclude the influence of random magnetic interference on the measurement while drilling system for drawing borehole trajectory accurately.In this paper,a hardware method and a software method are proposed according to the drilling process of horizontal kilometer directional drilling machine and general slewing drilling rig,to solve the problem that the current magnetic-based measurement while drilling system is easily interfered by random unstable magnetic field.The hardware anti-magnetic interference method introduces the tri-axial gyroscope in the original sensor model,and uses the data fusion method to compensate the disturbed measurement points at the attitude angle aspect.The software anti-magnetic interference method acquire trajectory model by using support vector regression machine to train the undisturbed measurement point in the trajectory,and forecast the azimuth of the disturbed points.Then the magnetic interference is ruled out.(4)The horizontal trajectory tracking the design trajectory accurately is an important factor to achieve hitting the target.In this paper,in order to improve the present situation that the tracking and guidance of borehole trajector all depend on the workers’ experience,a tracking algorithm for the automatic guidence is proposed to Horizontal Directional Drilling machine on the basis of the optimal tracking theory and the principle of shortest distance,through the way of researching the mechanical model of single bend screw drilling tool at hole bottom and the drilling speed equation for Horizontal Directional Drilling machine.This algorithm is used to calculate the optimal tool-face angle of next drilling stem based on the trajectory prediction model,to achieve actual borehole trajectory tracking designed locus,which is of great significance to the practical application of Horizontal Directional Drilling machine in coal mine.