CAD-Based Measurement Path Planning for Free-Form Shapes Using Contact Probes

Dimensional inspection of engineering components comprising free-form surfaces demands accurate measurement of a large number of discrete points, such that the actual shape may be fully characterised. This paper presents a methodology for CAD-based measurement of such components using a coordinate measuring machine equipped with a touch-trigger probe. The main shortcomings of the conventional methodology have been identified to be in relation to registration and probe radius compensation. The proposed measurement process involves the following main steps: registration, definition of measurement points, probe path generation, path optimisation and verification, measurement and probe radius compensation. By employing the CAD model at every step, the implemented methodology maximises the measurement accuracy and this is verified through a detailed simulation study. In addition, the implemented tools for CMM programming achieve accurate control of the overall measurement process and provide a high level of confidence when dealing with complex component geometry.

[1]  Weiyin Ma,et al.  Parameterization of randomly measured points for least squares fitting of B-spline curves and surfaces , 1995, Comput. Aided Des..

[2]  Jim Hall,et al.  A Unified, Object‐Oriented Graphics System and Software Architecture for Visualising CAD/CAM Presentations , 1996, Comput. Graph. Forum.

[3]  Saïd Zeghloul,et al.  SMAR: A Robot Modeling and Simulation System , 1997, Robotica.

[4]  Christian H. Fedrowitz.  Fast intersection detection algorithm for PC-based robot off-line programming , 1994, Other Conferences.

[5]  Jun Ni,et al.  An Algorithm for the Generation of an Optimum CMM Inspection Path , 1994 .

[6]  B. Barsky,et al.  An Introduction to Splines for Use in Computer Graphics and Geometric Modeling , 1987 .

[7]  N. Mort,et al.  Manufacturing systems simulation with enhanced visualisation using virtual reality techniques , 1995 .

[8]  Hong-Tzong Yau,et al.  Path planning for automated dimensional inspection using coordinate measuring machines , 1991, Proceedings. 1991 IEEE International Conference on Robotics and Automation.

[9]  C. Menq,et al.  Curve and surface approximation from CMM measurement data , 1996 .

[10]  Bijan Shirinzadeh.  Task planning and offline programming , 1996 .

[11]  Mihailo Ristic,et al.  Efficient registration of NURBS geometry , 1997, Image Vis. Comput..

[12]  Chia-Ju Wu.  On the representation and collision detection of robots , 1996, J. Intell. Robotic Syst..

[13]  Mooyoung Jung,et al.  Integrated precision inspection system for manufacturing of moulds having CAD defined features , 1995 .

[14]  D. Badouel.  An efficient ray-polygon intersection , 1990 .

[15]  C. P. Lim,et al.  CMM feature accessibility and path generation , 1994 .

[16]  Chia-Hsiang Menq,et al.  Localization of 3-D Objects Having Complex Sculptured Surfaces Using Tactile Sensing and Surface Description , 1991 .

[17]  D. Brujic,et al.  Analysis of free form surface registration , 1996, Proceedings of 3rd IEEE International Conference on Image Processing.

[18]  Les A. Piegl,et al.  The NURBS book (2nd ed.) , 1997 .

[19]  Hong-Tzong Yau,et al.  Automated CMM path planning for dimensional inspection of dies and molds having complex surfaces , 1995 .