Research On Torsional Vibration Characteristics Of Drill Pipe And Active Vibration Absorption Control Of Directional Drilling Equipment In Coal Mine

As coal mining becomes more efficient and intelligent,directional drilling technology has been widely used in coal mine gas extraction,mine water hazard prevention,and exploration of hidden hazard-causing geological factors underground.In directional drilling construction,the drill rod itself is used as a slender Flexible rod,due to factors such as uneven material and intermittent crushing in the process of the drill bit crushing the coal seam,it is easy to cause the torsion and forced vibration of the drill rod and propagate backward,which will cause the wear and tear of the drill rod and serious downhole accidents.Therefore,this article has carried out research on the torsional vibration characteristics and mechanism of drill pipes in the wide frequency range of drill pipes,designed an active drill pipe vibration absorber based on moving magnetic torsional actuators,and controlled related active vibration absorption.The algorithm has been researched and analyzed,and the main research work is as follows:First of all,the torsional vibration characteristics of the drill pipe of coal mine directional drilling equipment are studied.Through the establishment of the finite element model of the drill pipe system in Ansys Workbench,the modal analysis of the drill pipe assembly of different lengths is carried out to explore the change law of the natural frequency and main vibration mode of the drill pipe system;the torsional vibration dynamic model of the drill pipe is established based on the continuum theory,And based on the modal analysis method and the mode truncation method to obtain the dual-point excitation and dual-point output state space model of the drill pipe system,and then numerically simulate the dynamic response of the drill pipe torsional vibration system in the Simulink platform.Secondly,an electromagnetic drill pipe torsion active vibration absorber is proposed and the dynamic characteristics are analyzed.Based on the principle of active vibration absorber combined with the working conditions of the drill pipe,the structural scheme design of the drill pipe torsion active vibration absorber is completed by Solidworks,the dynamic model of the drill pipe torsion active vibration absorber and the driving torque transfer function model are established,and the active vibration absorber is tested The time-frequency domain dynamic response characteristics;based on the moving magnetic actuator scheme,the structural scheme design of the torsion actuator is completed,combined with the main magnetic flux flow direction,the equivalent magnetic circuit method is used to obtain the magnetic common energy of the system,and then the virtual displacement The electromagnetic torque characteristics were obtained by the method,and the two-dimensional transient magnetic field finite element simulation was carried out using Ansys Electronics Desktop to optimize and determine the circumferential structure parameters,and at the same time verify the theoretical deduction results.Then,based on the analysis of the dynamic characteristics of the drill pipe active vibration absorber,a simulation study of the control strategy of the drill pipe active vibration absorber was carried out.Based on the least mean square(Fx LMS)algorithm,the design of the drill pipe adaptive feedforward active vibration absorption control system is completed.From the perspective of the Wiener optimal solution,the influencing factors and laws of the algorithm stability,convergence speed and steadystate error are analyzed;The dynamic mathematical model of the active vibration absorber is simulated in the Simulink platform to study the active vibration absorption effect of the drill pipe under different frequency harmonic torque excitation,and compare it with the passive vibration absorption scheme,and further identify and model the control channel.The above is compared with the theoretical calculation modeling scheme for the vibration reduction effect.Finally,a simple prototype was processed and trial-produced on the basis of the designed active vibration absorber and control scheme of the drill pipe,and a scaleddown experimental platform was built according to laboratory conditions to verify and evaluate the vibration reduction effect.Complete the component selection,hardware configuration and related interface circuit design work of the equivalent experimental platform,write the lower computer program of the control algorithm and the upper computer control interface;through the inertial driving torque test experiment of the active vibration absorber prototype,the driving torque amplitude and Excite the relationship between the frequency of the excitation current to verify the feasibility of the electromagnetic torsional active vibration absorption principle;identify the secondary channel of the equivalent experimental platform through the offline identification method,and substitute the active vibration absorption control system for the drill pipe active vibration absorption experiment.The experimental results are compared with the passive vibration absorption results without current control,and it is verified that the proposed torsional active vibration absorber for drill pipe has a better vibration reduction effect.The paper has 69 pictures,9 tables,and 84 references.