Design of a real-time adaptive NURBS interpolator with axis acceleration limit

With recent advances in high-speed and high-accuracy machining, the NURBS interpolator has shown significant effect on dealing with the free-form curves and surfaces. The existing study aims at developing the adaptive interpolator which confines the chord error, the tangent acceleration, and jerk. However, the excessive axis acceleration is still unavoidable at the sharp corners and will deteriorate the contour accuracy. In this paper, a real-time adaptive NURBS interpolator considering the acc/dec capacity for each individual axis is developed to confine both the chord error and the axis acceleration. The maximum feasible feed and tangent acceleration range are deduced, respecting the given axis acc/dec limit. A two-stage feed determination scheme is applied to calculate the adaptive feed rate for each sampling period. A look-ahead window is utilized to improve the calculation performance for real-time application. Simulations and experiments are performed to verify the resulting feed rate, acc/dec profiles, and the real-time performance of the proposed interpolator.

[1]  Rida T. Farouki,et al.  Algorithms for time-optimal control of CNC machines along curved tool paths , 2005 .

[2]  Le Xie,et al.  Adaptive parametric interpolation scheme with limited acceleration and jerk values for NC machining , 2008 .

[3]  Seung-Han Yang,et al.  Design of jerk bounded feedrate with ripple effect for adaptive nurbs interpolator , 2008 .

[4]  Daniel C. H. Yang,et al.  Parametric interpolator versus linear interpolator for precision CNC machining , 1994, Comput. Aided Des..

[5]  Mi-Ching Tsai,et al.  A real-time predictor-corrector interpolator for CNC machining , 2003 .

[6]  Les A. Piegl,et al.  The NURBS Book , 1995, Monographs in Visual Communication.

[7]  Syh-Shiuh Yeh,et al.  Adaptive-feedrate interpolation for parametric curves with a confined chord error , 2002, Comput. Aided Des..

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

[9]  Congxin Li,et al.  Design of a real-time adaptive interpolator with parameter compensation , 2007 .

[10]  Min-Yang Yang,et al.  Development of a real-time trajectory generator for NURBS interpolation based on the two-stage interpolation method , 2005 .

[11]  Moshe Shpitalni,et al.  Realtime curve interpolators , 1994, Comput. Aided Des..

[12]  Mi-Ching Tsai,et al.  Real-time NURBS command generators for CNC servo controllers , 2002 .

[13]  Jingyan Dong,et al.  A Generalized Time-Optimal Bidirectional Scan Algorithm for Constrained Feed-Rate Optimization , 2006 .

[14]  Elizabeth A. Croft,et al.  Feed optimization for five-axis CNC machine tools with drive constraints , 2008 .

[15]  Syh-Shiuh Yeh,et al.  The speed-controlled interpolator for machining parametric curves , 1999, Comput. Aided Des..

[16]  Tae Jo Ko,et al.  NURBS interpolator for constant material removal rate in open NC machine tools , 2004 .

[17]  I. Ali,et al.  Advanced Interpolation Techniques for N.C. Machines , 1993 .

[18]  Jingyan Dong,et al.  Optimal Feed-Rate Scheduling for High-Speed Contouring , 2007 .

[19]  Sung Ho Park,et al.  Machineability in NURBS interpolator considering constant material removal rate , 2005 .

[20]  Daoshan Du,et al.  An accurate adaptive parametric curve interpolator for NURBS curve interpolation , 2007 .

[21]  Jiing-Yih Lai,et al.  On the development of a parametric interpolator with confined chord error, feedrate, acceleration and jerk , 2008 .

[22]  Ranga Narayanaswami,et al.  A parametric interpolator with confined chord errors, acceleration and deceleration for NC machining , 2003, Comput. Aided Des..

[23]  X. Zhiming,et al.  Performance Evaluation of a Real-Time Interpolation Algorithm for NURBS Curves , 2002 .