The Research On Automatic Merging Technique Of Hull Block Based On Adjustable Piers

The hull block merging, which not only has heavy workload and collaboration difficulty, but also requires high precision and difficult technology, plays a time-consuming and important role in the ship manufacture. Now, we still use two traditional methods to assemble the hull block, one is crane driver and assembly workers interwork to lift, locate the hull block, the other is using berth bogies to assemble the hull block. There are many shortcomings in the traditional assembly methods, such as low precision, low efficiency, complicated manual operation and low utilization rate in crane. Along with the rapid development of ship industry, the technology of slipway’s zero-allowance assembly builds up gradually, which significantly enhance the assembly efficiency and quality on the slipway. The emergence of hull block assembly equipments met the need of the technology of slipway’s zero-allowance assembly.In this thesis, the main research object is three-dimensional adjustable pier, which can realize the motion in the x-axis, y-axis and z-axis within a certant disatance. Four three-dimensional adjustable piers constitute a platform to support the hull block. The hull block could be merged apace by adjusting the four three-dimensional adjustable piers synchronously. The main content of this paper is as follows:(1) For a three-dimensional adjustable pier which is designed by Dalian University of Technology, a moving model for the automated hull block connection and location system is established, an optimization method of the motion trail of the hull block assembly which is based on movement time is put forward. How to improve motion stability of the hull block also is considered.(2) The geometric constraint equation between the position of each three-dimensional adjustable pier and the position and posture of the hull block is established. When the motion trail of the hull block is planned, we can get the motion trail of each three-dimensional adjustable pier by using the method of solving inverse kinematics. A measuring and computing method of the position and pose of the hull block is introduced.(3) A calculation program for the automatic joint of hull block is developed by using VB.NET, the program achieves a lot of functions, such as calculating the position and pose of the hull block, planning motion trajectory, solving inverse kinematics, outtputing trajectory curve and saving data. CATIA is using to simulate the hull block assembly, which has proven the calculation program’s feasibility.