Research On Automatic Generation Technology Of Measurement Point Based On CATIA

Automatic generation of measurement point is the primary link and key content ofComputer Aided Inspection Planning system (CAIP), is also the premise and foundation ofthe planning of measuring path, and it has important effect on the establishment of wholecomputer aided inspection planning system. Accordingly, the research on the technology ofautomatic generation of measurement point has great research value and significance.In view of the current development and research situation for technology of automaticgeneration of measurement point, this article analyzed and studied the technology ofautomatic generation of measurement point based on IGES, that which is theimplementation platform is secondary development of CATIA.Firstly, summarizes the technology of secondary development of CATIA based onCAA\C++, analyzes the Component Application Architecture (CAA) and Rapid ApplicationDevelopment Environment (RADE). Meanwhile, studies the file structure, element, and datarecord format of IGES, and based above, analyzes the feasibility of generating ofmeasurement point based IGES.Secondly, confirms and studies the sampling strategy of measurement point based onIGES, according to the representation and characteristic of surface in IGES file, put forwardthe sampling strategy that combines uniform sampling and inserting sampling pointsaccording to curvature variation, and designs specific sampling rules for three commonsurface type in IGES, besides, formulates the scheme that mapping surface boundary tonormalized2-D parameter space to delete those sampling points on cut surface part.Then, around the initial path planning of measurement，in order to reduce the influenceon measurement precision and efficiency from measurement direction and velocity, studiesand formulates the principle that making the direction of surface normal as the measuringdirection, and designs respectively corresponding calculation method of measuring direction for that three types of surfaces, meanwhile, the further studies the setting principle ofmeasuring anchor point and measuring search section, in addition, combining the analysis ofmeasurement sequence planning, plans the initial measurement path. To achieve globalmeasurement and guarantee measurement safety, studies and formulates the matching schemeand algorithm of surface boundary, thereby lay the foundation for subsequent collision checkand obstacle avoidance.Finally, combining with secondary development of CATIA based on CAA\C++,establishes the module of automatic generation of measurement point in CATIA, and realizesthose functions: generation of measuring point, calculation of measurement direction,certainty of measuring start point, generation of initial measurement path and matching ofboundary etc.