Identification and geometrical modelling of complex shape surfaces using coordinate measuring machine and CAD/CAM systems

Abstract

Two similar methods for the geometric identification of complex shape surfaces using the scanning measurement technique on a coordinate measuring machine (CMM) will be presented in this work. The first method employs the surfaces defined by the CAD system parametric technique based on the set of measurement points. The coordinates of points in space are determined by measurement in successive scanning planes with a given measuring step. The second method employs the surfaces defined by the analytically generated orthogonal curve meshes given by Newton's interpolation function. The interpolation points are the measurement points in the Cartesian space for a given measuring step. The generation technique of the interpolation function is then applied by using the interpolation method to define the arbitrary coordinate point set of the range of the measured net. Following this method of identification, some corrective procedure for measuring the results of surface coordinate points are proposed. These correction procedures result from use of the probe end in the coordinate technique. As a consequence of the presented corrective procedures, the authors propose useful software (numerical programmes) for the applied CMM during measuring of the complex shape surfaces. In the final part of the work, the sets of points obtained from these measurements are used to the develop 3D geometrical models of surfaces in the CAD system. The discussed techniques of identification and modelling are adopted in the design of a TV tube and the shape surface of the radial bone in bioengineering as practical examples.