Real time forward looking whole-process acceleration and deceleration controlled NURBS curve self-adapting subsection interpolation method

Abstract

The invention discloses a method for self-adaptive subsection interpolation of NURBS curve under the real-time look-ahead whole-process accelerated and decelerated control. The NURBS curve is presented by a matrix form and is pre-processed; the self-adaptive speed adjusting arithmetic is adopted for the NURBS curve, thus obtaining the parameters meeting the interpolation precision requirement such as feeding speed and the like; the curve is segmented at all maximum curvatures of the curve; speed planning is carried out on all the segmented curves by an S-curve accelerated and decelerated control method, thus obtaining the changing time of the speed curve at all accelerated and decelerated stage; according to the interpolation period and the changing time of all accelerated and decelerated stage, the feeding speed of all interpolation periods and coordinates of corresponding interpolation points are obtained; and according to the coordinates of the interpolation points and the feeding speed, the control signal given value is generated. The invention can realize the look-ahead processing of the NURBS curve during the whole interpolation process, leads the real-time interpolation process to be quick and effective, leads the whole interpolation movement process to be smooth and stable, has wide applicable range and has important significance to the development of the high-speed high-precision numerical control system.

Description

Technical field [0001] The invention relates to the field of numerical control systems, in particular to an adaptive segmented NURBS curve interpolation method with forward-looking function and real-time full-process acceleration and deceleration control in the motion control technology of numerical control machine tools or articulated robots. Background technique [0002] Non-Uniform Rational B-Spline (Non-Uniform Rational B-Spline, referred to as NURBS curve) has become an industry standard for computer geometric information expression, design and data exchange due to its flexible design and stable algorithm. It is used in CAD / CAM systems. It is widely used, and a large number of free-form surfaces in aerospace, aerospace, automobile, mold and other industries are represented by NURBS curves. The advantages of NURBS curve interpolation in high-speed processing are mainly reflected in: complete curve information, greatly simplified program code, higher processing accuracy, faste...

AI Technical Summary

Problems solved by technology

Taking the machine constant (maximum acceleration, maximum jerk) and the allowable maximum chord height error as constraints, the S-curve acceleration and deceleration control method is used to plan the full interpolation feed rate of the NURBS curve, so that the entire interpolation motion process is smooth and stable, and It meets the requirements of interpolation accuracy and solves the problem of difficult prediction of deceleration points at the same time. It is a numerical control interpolation control method with a wide range of applications.

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