Research On Computer Aided Inspection Planning System

Nowadays, it is indispensable to research on Computer-Aided Inspection Planning System (CAIP) system. CAIP plays one important role in insuring product quality. Supported by Sino-Germany cooperation project - ProSens, this dissertation presents the analysis of the characteristics of CAIP and proposes the prototype system of ProSens. Grounded on measuring knowledge, ProSens is designed to be capable of making inspection plans for various inspection features according to their accuracy requirements respectively. Multiple sensors integration is one outstanding character of ProSens. DMIS is used to transfer the output plans to NC codes for specific Coordinate Measuring Machine (CMM).Firstly, the analysis of CAIP is made. The concept of knowledge-based multiple sensor integration inspection planning system is brought forward. ProSens system consists of several modules: inspection recognition, measurement equipments selection, measurement planning, fixture planning and expert systems. Function structure diagrams are designed for every subsystem. IDEF0 method is utilized to describe the relationship among all subsystems and to illustrate the mechanism of subsystems.One uniform product information model is designed on STEP, using object-oriented methodology. CAD/CMM/CAIP operations are encapsulated in class. The class integrates tolerance information and inspection features information. This model provides interface between CAD and CAIP with the integration of geometric information, tolerance information, measuring elements and surface features.Some critical technologies in CAIP have been investigated. Automated measuring equipments selection method is analyzed. This paper presents a flowchart of measurement equipments selection. Hamersley measurement points distribution algorithm is improved to extend its application scope. A new algorithm of obstacle-avoiding method is given, and this method can reduce the inspection path length effectively, and raise the inspection efficiency.The inspection feature recognition subsystem is developed with UG/Open API. In UG environment, the inspection features are extracted from CAD model. The features are the information source of ProSens. The prototype of measurement points planning subsystem has been devised and developed. The number of measurement points is determined by the analysis of selected surface geometric information based on rules. Even distribution principle is used for measurement points distribution.