Research On3D Measurement And Positioning Control Method For Hull Block Construction

With the development of science and shipbuilding technology, the shipbuilding mode is moving on the direction of gigantic block in order to improve the efficiency and quality of shipbuilding. Therefore it makes more demands of designing and manufacturing and other sectors. How to quickly and accurately measure the error between the theoretical model and real product in construction process, and how to increase positioning efficiency of docking in assembly process, have become the hotspot of academic research at home and abroad, so it has important theoretical significance and application value onstudying these issues.This article launched further research work on these issues on the basis of the current research archeivement made by experts at home and abroad. The main research contents include:(1) Study the deformation and the anti-deformation measures in the process of hull construction. In the process of hull construction, welding, placing on pier, lifting and shifting can cause deformation of hull block. This paper analyzes the cause of hull deformation, and propose corresponding measures against deformation according to different deformation type.(2) Study the hull block large-scale measurement methods usingtotal station. This paper analyzes the large scale three-dimensional measurement method of hull block in the process of construction and assembly, discusses the selection principle of theoretical point set, and the matching method between theoretical point set and measurement point set, proposes the improved three point alignment method of selecting the central point based on least square method after taking the characteristics of three-dimensional measurement of hull block and aiming at the shortage of point set matching in alignment method,. About the IPC method frequently used in the matching of non-correspondence point set, this paper proposes a new way of matching the point set by PCA in general and then matching the point set by ICP finely, which can improve the matching accuracy effectively.(3) Study the hull block assembly automation systems and control method. The existing assembly methods occupies long crane time and have security issues, this paper designes a three-dimensional adjustable platform used for hull block assembly. The system consists of several three degree of freedom adjustable pier, and using single pier can achieve a range of three-dimensional movement. When it turnsto group pier control mode, system can achieve multi degree of freedom of movement, and then realize a safe, efficient, high-accuracy technology of hull block assembly and positioning. (4) Study the hull block positioning control method based on the theory of multi-innovation. It is difficult to establish mathematical model for the hull block docking as it is a nonlinear system, this paper deeply studies the adjustable platform control method issues, theoretically proves the convergence of the model free control based on the multi-innovation theory, optimizes the control parameters online by using genetic algorithms, proposes a PID neural network control algorithm based on multi-innovation theory, and proves its convergence. Finally, this paper use multiple simulation instancesto verify these two improved algorithms, and the results show that the improved two control algorithms converges faster with strong robustness.(5) Oriented to the shipbuilding engineering practice, this paper makes a three degrees of freedom adjustable pier prototype, proposes adjustable pier control system frame structure based on the development of open control system specification., developes the hardware and software platform of adjustable the pier control system, and implement the proposed PIDNN control algorithm based on multi-innovation theory in platform control algorithm library, and the actual control results further validate the effectiveness of the proposed method. This paper also developes a hull block large-scale measurement error analysis system and an assembly simulation system, which achieved functions as error analysis and simulation analysis of hull block no-margin construction, margin measuring error analysis and assembly simulation. The results of this study have been applied to several shipbuilding projects in Guangxin Shipbuilding&Heavy Industry Co., Ltd., and acheives a good practical effect.