Method For Automatic Forming Inspection Of Ship HullPlate

In process of the hull construction,digitalization had been fulfilled on certain aspects such as design,lofting,marking and cutting,the same as mechanization and pipelining on assemble and jointing.However,on forming and inspection,handcraft is always on work.Nowadays,shipyards generally use triangle template and adjustable form-checking template.Building triangle template,not only waste too many materials,but is inefficiency and terrible working environment as well. Following appeared adjustable form-checking template which saved materials and improved efficiency to a certain degree,but virtually it's manual inspection,so difficulty always on improvement of efficiency and precision,and to be a choke point to improve producing efficiency.Technologists study the advanced computing laser non-contact measurement to take the place of the traditional measurement like using template and model case,to improve the forming efficiency and reliability of data, provide a better way for measurement and precision ship-production.Moreover,it saves plenty of materials for template,reforms working environment and ensures the fulfillment of numerical control.The paper provides a method for digital template inspection:on the base of inspection of adjustable form-checking template,using non-contact laser measure setting and displacement sensor,locating 3-d coordinates of a series of discrete points on the surface,having transform these coordinates,then contrasting with theoretic data of frame line,distinguishing landscape orientation,portrait twisting and cleanness of the hull shell plate.To establish the model of inspection,other terms such as equipment should be considered.This method basically on the choosing of way for measure,establishing reference frame,coordinate conversion,curve fitting, error analyses of forming,etc.The characters of this model contain:1)On the base of inspection of adjustable form-checking template,getting 3-d coordinates of a series of spots on certain frame through distance sensor,to make line by spots and the surface will be instead by the line,to set up a basic for digital forming inspection.2)Using non-contact method,the process to making templates will be saved up and only frame line be provided.On the other hand,inspecting equipment(e.g.laser sensor)will not influent the processing of the forming equipment,and benefit for auto-forming for materialswhen measuring.3)Using manipulator to locate the point(manipulators hold two sides of the plate, and is driven when processing and measuring).And then it becomes the basic of establishing the reference frame,coordinates conversion,curve fitting and error analysis.