Research On Pivotal Techniques For Intelligent Machining Equipment For Complex Ship Hull Plates

Shipbuilding,as a comprehensive and strategic industry for water transport,marine resource exploitation and national defense,is a powerful underpinner for China to realize its grand strategy of becoming a maritime powerhouse.However,China’s shipbuilding industry still lags behind its counterparts in Japan and Korea in terms of automated equipment and technology.To change this situation,China launched its "Made in China 2025”initiative in 2016,designating marine engineering equipment and hi-tech vessels as among the ten key priority areas of development,in a hope of achieving transformation and upgrade in sectors of high-end equipment and technology and shipbuilding.Ship hull plates are the key part for realizing water tightness,withstanding external water pressure and resisting waves,whose processing time accounts for 20%～3 0%of the whole hull building time,which directly influences the building cycle and vessel quality.However,the bend-forming processing in most of Chinese shipyards are carried out manually,an approach troubled by low processing efficiency,high reject rat and vast energy consumption.Therefore,this project seeks to look at key technologies concerning smart molding equipment of ship hull plates,in hope of transforming the traditional manual approaches.And the specific research contents are as follows:1.3D measurement and mesh reconstruction method of ship hull plates.In order to solve the problem of precise positioning of the ship hull plates,the following research works were mainly carried out in this project.Firstly,the 3D laser scanning technology was studied to obtain the point clouds of the ship hull plates.Secondly,the technologies of preprocessing and clustering extraction of point clouds were studied.And the point clouds of the ship hull plates were extracted from the measurement data by the technologies.Then,the freeform curve reconstruction method of ship hull plates was studied to transform the large and scattered point clouds into regularly arranged grid points.Finally,in order to realize the positioning of the ship hull plates,the 3D coordinate transformation technology of the measurement coordinate system to the robot movement coordinate system was studied.2.Expert rules reasoning technology for processing parameters.In order to solve the problem of automatic reasoning of the processing parameters of the plates,the following research works were mainly carried out in this project.First of all,the forming process of the ship hull plate was studied,and the architectural of the process rule database of the plate was designed.Then,the classification rules and the inference rules of flame path and the inference rules of heating parameters of the plate were studied.And then all the rules were described by the computer language.Lastly,the rules inference mechanisms of processing parameters of the plates were studied.And the rules would be transformed the into control texts,which could be executed by the robot and guided the robot to carry out the actual processing,by the rules inference mechanisms.3.Programming method for the secondary processing parameter.In order to realize the automatic programming of the secondary processing parameters of the plates,and ensure that the robot does not enter the dead-end processing state,the following research works were mainly carried in this paper.Firstly,the evaluation method for ship hull plates’ process molding was studied,and the current forming state of the outer shell was comprehensively analyzed.Secondly,the programming method for the secondary processing parameter was studied,which were based on the flame path programming method based on angular deformation and the angular deformation calculation method and the evaluation method,to realize the programming of the secondary processing parameters of the ship hull plates.Finally,the basis for judging the convergence of the ship hull plates processing was studied to ensure the convergence of the forming process.At last,the methods studied in this subject would be integrated into the longmen type line heating robot,which was developed by Guangzhou Guangchuan International Co.,LTD and Guangdong University of Technology.And the methods would provide the 3D information of the plates for the robot,as well as the flame path and the processing parameters.Finally,the methods will realize the intelligent processing of the ship hull plates,and change the situation of the manual processing of the ship hull plates.