Inspection path generation in haptic virtual CMM

Abstract

An inspection path generation methodology for virtual coordinate measuring machines (VCMM) based on haptic technologies is presented in this paper. Introducing a haptic device into CMM inspection path planning leads to the development of the proposed novel CMM off-line inspection path planning environment called haptic virtual CMM (HVCMM). HVCMM is an accurate model of a real CMM, which simulates a CMM’s operation and its measurement process in a virtual environment with haptic perception. Due to the force feed back in the operation, the inspection path planning process is more intuitive, efficient, and user-friendly. The inspection path generation procedure is carried out in several steps: first, the measuring points are selected by operators using “point-and-click” method; second, the measuring points are offset according to the surface geometry and the offset points are linked with line segments; third, the linked path is traced by the virtual CMM probe to perform collision detection; fourth, when a collision occurred, an auxiliary point method and a teach pendant method are developed to generate a collision-free path with the aid of haptic constraint plane. The aim of these algorithms is to minimize the computation of collision detection. Examples are given on a HVCMM prototype system to demonstrate the proposed methodology.