Arc length parameter curve processing track generation method of free curved surface

Abstract

The invention relates to an arc length parameter curve processing track generation method of a free curved surface. The method comprises following steps of smooth and continuous characteristic curve processing track extraction, given precision parameter curve processing track generation and processing track arc length parameterization. In the step (1), processing tracks generated by computer aidedmanufacturing software (CAM) are classified according to arc length characteristics; and discrete free curve processing tracks with smooth and continuous characteristics are extracted; in the step (2), fitting is performed on the extracted discrete free curve processing tracks under the given precision, so parameter curve processing tracks meeting a geometric representation precision requirementare obtained; and in the step (3), by use of the method of continuous iteration arc length re-parameterization, arc length re-parameterization is performed on the parameter curves obtained in the step(2), and finally, the arc length parameter curve free curved face processing track is obtained. According to the invention, the difficulty level in real-time interpolation and speed planning in freecurved face processing is reduced; and smoothness and processing precision in the processing process are improved.

Description

Technical field [0001] The invention belongs to the technical field of numerical control processing, and specifically relates to a method for generating a free-form surface arc length parameter trajectory. Background technique [0002] Traditional free-form surface machining mainly uses a large number of discrete small line-segment trajectories generated by computer-aided manufacturing software (CAM), and then realizes it through online smoothing and speed planning. However, with the development of aerospace, automobile, ship and other fields, the processing requirements for free-form parts such as blades and molds are getting higher and higher. However, due to the strict control of the amount of online real-time calculation, the traditional free-form surface processing method cannot achieve good high-speed and high-precision free-form surface processing, it is difficult to ensure the contour accuracy and surface quality of the processed surface, and the processing efficiency is ...

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Problems solved by technology

Literature (Lin K Y, Ueng W D, Lai J Y. CNC codes conversion from linear and circular paths to NURBS curves [J]. International Journal of Advanced Manufacturing Technology, 2008, 39 (7-8): 760-773.) studied the small The CNC machine tool (CNC) machining trajectory composed of line segments and arcs is converted into a non-uniform rational B-spline (NURBS) method, but due to the complexity of non-uniform rational B-spline (NURBS) interpolation and speed planning, the generated non-uniform rational B-spline (NURBS) Uniform Rational B-spline (NURBS) curves are still difficult to apply to production practice

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