Constrained and Unconstrained Localization for Automated Inspection of MarinePropellers

摘要

This work addresses the problem of optimal positioning of a set of measuredpoints with respect to an ideal design surface. Localization refers to the process of determining the rigid body translations and rotations which must be performed on the set of points to move those points into closest correspondence with the design surface. In unconstrained localization all points have equal effect on the determination of the rigid body transformation, while constrained localization allows a subset of the points to have stronger influence on the transformation. The measured points in the context of this work refer to physical points in space that are obtained by direct measurement of a manufactured marine propeller blade. The ideal design surface refers to a surface description of the propeller blade provided by the blade designer. Given that the measured blade is manufactured from the design surface description, it is the task of localization to determine an optimal positioning that will bring the measured points of the manufactured surface as close as possible to the design surface. If the manufactured blade is repositioned in space according to the prescription of the localization transformation, it will have the closest possible correspondence to the original design. Direct benefits to the manufacturer may result from less wasted material in initial castings and better ability to program postcasting work through optimal positioning of the workpiece.