Methods of Robotics and the Pseudoinverse to Obtain the Least-Squares Fit of Measured Points on Line-Profiles

摘要

Tolerances on line profiles are used to control cross-sectional shapes of parts, such as turbine blades. A full life cycle for many mechanical devices depends (i) on a wise assignment of tolerances during design and (ii) on careful quality control of the manufacturing process to ensure adherence to the specified tolerances. This paper describes a new method to improve the quality control of a manufacturing process by converting measured points on a part to a geometric entity that can be compared directly with tolerance specifications. The focus of this paper is the development of a new computational method for obtaining the least-squares fit of a set of points that have been measured with a coordinate measurement machine along a line-profile. The pseudo-inverse of a rectangular matrix is used to convert the measured points to the least-squares fit of the profile. A numerical example is included for a convex line-profile that is formed from line- and circular arc-segments.