Dynamics Analysis Of Automatic Grabbing Crane Of Offshore Drilling Rig

With the escalation of the water depth of the drilling platform operation in sea, thenumber of drill pipes for drilling operation increases relatively, and so do the time andexpenses for the operation. Namely labor strength and risks go up for rig workers. Automaticgrabbing crane of offshore drilling rig enables workers to keep off poor working conditionsand dangerous areas, improving the security of the whole operation. Manual work replaced bymachineries to complete actions, the automation of operation process can be achieved. Laborstrength for workers get lessened, in the meanwhile, work efficiency can be improved, workhours can be shortened, and operation cost is to be lowered.Automatic grabbing crane of offshore drilling rig is taken as a robot of6-DOF accordingto the thesis, creating the coordinate system of each connecting rod with the method of RobotD-H, using coordinate transform matrix to describe the relative positions and directions of thecoordinate system of connecting rods, furthermore, and the kinematical equation of theautomatic grabbing crane needs working out. The position and posture of the end-effectorbeing known, inverse transform technique is used to solve inverse of kinematics, and thenfigure out each joint angle. Use robotics toolbox in MATLAB to conduct the simulation thekinematics model of automatic grabbing crane. Simplify the mechanical model of6-DOF,utilize the simplified model of rigid multi-body dynamics to conduct kinetic analysis,deducing the dynamics equations of1stto5thlinks based on Lagrange principle. Based on thevirtual prototyping simulation of ADAMS platform and considering gravity, moment of inertia,blowing force of wind and waves load, a series of valuable parameters of automatic grabbingcrane can be obtained.As has been mentioned above, the research confirm the measurement of the arms insideand outside of automatic grabbing crane of offshore drilling rig; it also confirms that the modeof motion of the train of mechanism is uniform acceleration-uniform speed-uniformdeceleration; the end of the holder, the speed of arms inside and outside, acceleration speed,angular speed and acceleration curve are worked out while the automatic grabbing crane isbeing operated; based on the virtual prototyping simulation of ADAMS, the condition of eachjoint’s stress and moment of force can be seen.The dynamics analysis of automatic grabbing crane is significant for its track programming, kinematics simulation and dynamics simulation. It is also instructive for theapplication on the spot of automatic grabbing crane. The situation changes of kinematics anddynamics can be known by stimulation, thus, the basis for further research can be provided.These play an important role in studying automatic grabbing crane from the aspects of themechanics analysis and are instructive for practical designing, research and development, andoperation.