A novel path generation method of onsite 5-axis surface inspection using the dual-cubic NURBS representation

Abstract

Onsite surface inspection with a touch probe or a laser scanner is a promising technique for efficiently evaluating surface profile error. The existing work of 5-axis inspection path generation bears a serious drawback, however, as there is a drastic orientation change of the inspection axis. Such a sudden change may exceed the stringent physical limit on the speed and acceleration of the rotary motions of the machine tool. In this paper, we propose a novel path generation method for onsite 5-axis surface inspection. The accessibility cones are defined and used to generate alternative interference-free inspection directions. Then, the control points are optimally calculated to obtain the dual-cubic non-Uniform rational B-splines (NURBS) curves, which respectively determine the path points and the axis vectors in an inspection path. The generated inspection path is smooth and non-interference, which deals with the ‘mutation and shake’ problems and guarantees a stable speed and acceleration of machine tool rotary motions. Its feasibility and validity is verified by the onsite inspection experiments of impeller blade.

Surface form inspection with contact coordinate measurement: a review

“…Li et al [1] applied the dual-cubic NURBS curves to represent the path points and the probe orientation. By adjusting the number of control points of the dual-cubic NURBS curves, an inspection path is obtained, which simultaneously guarantees the global interference-free constraints and avoids the unfairness of the rotary axis motion.…”

“…Freeform surfaces are widely used in various fundamental industrial products, such as impeller blades [1], high-precision molds [2], aircraft skin [3], and so on. High-quality measurement of the freeform surface is crucial to the quality control of these products or guiding the further five-axis machining process.…”

A novel path generation method for robotic measurement with local pruning and collision-free adjustment

“…However, the global-based path-pruning methods need a lot of collision detection. After path pruning, it is necessary to interpolate or fit the paths using higher order curves, for example, five polynomial curves [25], Bézier curves [26], B-spline curves [27,28] or non-uniform rational B-splines [29]. It shows that the above shortcuts method does not consider the selection of pruning path points, which usually results in a large number of collision detections during the path pruning.…”