<p>In current industrial practice, the transformation of Computer-Aided Geometric Design surfaces into Computer Numerical Control (CNC) machine tool axis commands is performed with the aid of Computer-Aided Manufacturing software and a closed CNC machine tool controller. The advent of new technologies such as Open Architecture Control has enabled the rethinking of motion command generation. This thesis describes a five-axis motion command generation architecture and algorithms in which a parameterized tool-path is interpolated off-line and the inverse kinematics mapping is performed in real-time, on the CNC controller. This architecture eliminates the need for time consuming repost-processing of the tool-path in the event of kinematic changes and additionally introduces the benefits of parametric splines with controlled feedrate. To deterministically attain a near constant feedrate tool-path, near arc-length parameterized splines are prepared off-line. The C2 position spline which is near arclength parameterized improves on the previously reported research. The orientation unit vectors are interpolated with a C 2 spherical Bézier spline. These two splines are then synchronized by means of a monotonic reparameterization spline. This results in reduced effective feedrate oscillation. The interpolated tool-path and axis commands are demonstrated to be smooth and C2 continuous. To cope with actuator saturation, a feedrate interpolation algorithm is developed which ensures C2 continuity but allows the feedrate to be adjusted as needed. The developed algorithms were simulated for two tool-paths and two five-axis machines tools. A test part was cut to demonstrate geometric correctness.</p> / Doctor of Philosophy (PhD)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/7186 |
| Date | 12 1900 |
| Creators | Fleisig, Robert V. |
| Contributors | Spence, Allan D., Mechanical Engineering |
| Source Sets | McMaster University |
| Detected Language | English |
| Type | thesis |
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