Research Of Modeling Theory And Experiments On Carrying Strings Mechanical Arm In The Oilfield

Carrying strings mechanical arm is one of essential equipments in workover and drilling,it has very high working frequency and need to implement the mechanical automation.This kind of equipments'characteristics are a large scope of work and the poor working environment.And its motion precision,response speed and control lability are demanded higher and higher.Therefore,research of modeling theory and experiments on carrying strings manipulator has great significance to improve the design level and working performance of such equipments.In this paper,based on full investigation and analysis of the progress of oilfield operation and domestic and aboard removing strings mechanical automation technology,a kind of strings transmission equipment with lifting mechanical arm and the research idea in coupled dynamics model are put forward.In this scheme,mechanical arm is as a flexible body.The coupled system model is established and such problems as the simulation and modeling theory and experiment are studied and analysised in depth.Carrying strings system mainly consists of mechanical arm,rotating mechanism and mechanical hands.The paper introduces overall structure of system and the function,working principle and technological process of main components.Then,the 3D model of the system is created in SolidWorks software.With ADAMS multi-body modeling theory,the paper firstly simplifies all parts of the system to a plane.Then the rigid model of arm,rotating mechanism and hands are established.Through studing the single flexible mechanical arm with mass block at the end,the orthogonality conditions of inherent vibration of arm is reduced,the coupled numerical calculation model of carrying strings mechanical arm are established based on the lagrange equation.It provides the theoretical basis for describing the dynamic behavior of the flexible mechanical arm.Combining with ADAMS and ANSYS software,we conduct the finite element analysis and establish the coupled model of mechanical arm.Dynamics simulation of the coupled system and analysis of the dynamic characteristics in lifting process of mechanical arm and rotating and opening-closing process of hands are made.Then the numerical simulation of rigid-flexible coupling mechanical arm is performed to inspect the influence of liftting speed,arm structure and end quality,driving mode,strings with different dimensions.The establishing condition of rigid-soft model in multi-body system and the primary and secondary factors influencing the vibration characteristics of flexible arm are refined.It is concluded that:Target position location and stability problem of arm can be completely solved.The simulation of the flexible components is closer to reality.The coupled analysis idea can reveals the essence of the system when a mechanical system is designed.Then we analysis the contact collision model.Contact collision phenomenon with different parameters are simulated and compared in the collision process in ADAMS software.The collision force curve is get,the influence rules of stiffness damping coefficient of the damper and weight of strings is studied.It is concluded that the weight of strings has little influence on the vibration characteristics.On the basis of the above theoretical study,experiment study of mechanical arm for work characteristics is carried.Contrast of test results and simulation results is made and the error causes between the test data and the simulated data are analyzed.It is verified that theoretical models of the system is right and simulation techniques are feasible to study system dynamic characteristics.The simulation results are helpful to understand the working characteristics of the system thoroughly and comprehensively.To sum up,through the numerical simulation and experiment,with the theory of ADAMS multi-body model,the rigid-flexible coupling numerical model is set up and the vibration characteristics of flexible arm of system is found and the influence of structural parameters and operational parameters on the system are obtained.The results can provide theoretical method for the design of similar institutions in various fields.At the same time,it also can be used as a basic research for characteristics in similar coupled mechanism and has important practical significance.