Integrated accessibility analysis and measurement operations sequencing for CMMs

Effective integration of the different tasks involved in CMM inspection planning is a key issue in the development of an automated and robust inspection planner. This problem has not yet been well addressed due to the lack of a formalized and integrated approach for accessibility analysis, measurement operations sequencing, and resource allocation. This paper presents a novel methodology that integrates robust analysis of the accessibility of geometric features by the CMM probe with optimum sequencing and resource allocation. The accessibility analysis is based on ray-tracing algorithms and takes into account the actual size and position of the probe. A new notion of principal clusters, which represent all possible maximum clusters of measurement points accessible with the same set of probe orientations, is introduced. Each of these clusters is associated with a specific set of probe orientations represented as a Tool/Operation matrix. The accessibility analysis is followed by establishing the optimum sequence of measurement points and optimally selecting the probes and their orientations. This methodology is believed to provide useful contributions to the development of an automated CMM inspection planner.