The feedrate profile of non-uniform rational B-spline （NURBS） interpolation due to the contour errors is analyzed. A NURBS curve interpolator with adaptive acceleration-deceleration control is presented. In interpo-...The feedrate profile of non-uniform rational B-spline （NURBS） interpolation due to the contour errors is analyzed. A NURBS curve interpolator with adaptive acceleration-deceleration control is presented. In interpo- lation preprocessing, the sensitive zones of feedrate variations are processed with acceleration-deceleration control. By using the proposed algorithm, the machining accuracy is guaranteed and the feedrate is adaptively adjusted to he smoothed. The mechanical shock imposed in the servo system is avoided by the first and the second time derivatives of feedrates. A simulation of NURBS interpolation is given to demonstrate the validity and the effectiveness of the algorithm. The proposed interpolator can also be applied to the trajectory planning of the other parametric curves.展开更多
Variable feedrate interpolation algorithms for five-axis parametric toolpath are very promising but still rather limited currently.In this paper,an off-line feedrate scheduling method of dual NURBS curve is presented ...Variable feedrate interpolation algorithms for five-axis parametric toolpath are very promising but still rather limited currently.In this paper,an off-line feedrate scheduling method of dual NURBS curve is presented with geometric and kinematical constraints.For a given dual parametric curve,the feedrates of sampling points are first scheduled sequent with confined feedrate of cutter tip and machine pivot,chord error,normal acceleration and angular feedrate.Then,the feedrate profiles of angular feed acceleration sensitive regions of the path are adjusted using a bi-directional scanning algorithm.After that,a linear programming method is used to adjust the feedrate profiles of linear feed acceleration sensitive regions and control the linear feed acceleration of both cutter tip and machine pivot within preset values.Further,a NURBS curve is used to fit the feedrates of sampling points.Finally,illustrative examples are carried out to validate the feasibility of the proposed feedrate scheduling method.The results show that the proposed method has the ability of effectively controlling the angular feed characters of cutter axis as well as the chord error and linear feed characters of cutter tip and machine pivot,and it has potential to be used in high accuracy and high quality five-axis machining.展开更多
基金Supported by the Natural Science Foundation of Jiangsu Province(BK2003005)~~
文摘The feedrate profile of non-uniform rational B-spline （NURBS） interpolation due to the contour errors is analyzed. A NURBS curve interpolator with adaptive acceleration-deceleration control is presented. In interpo- lation preprocessing, the sensitive zones of feedrate variations are processed with acceleration-deceleration control. By using the proposed algorithm, the machining accuracy is guaranteed and the feedrate is adaptively adjusted to he smoothed. The mechanical shock imposed in the servo system is avoided by the first and the second time derivatives of feedrates. A simulation of NURBS interpolation is given to demonstrate the validity and the effectiveness of the algorithm. The proposed interpolator can also be applied to the trajectory planning of the other parametric curves.
基金supported by the National Natural Science Foundation of China under Grant Nos.51075054 and 11290143the National Basic Research Program of China under Grant No.2011CB716800
文摘Variable feedrate interpolation algorithms for five-axis parametric toolpath are very promising but still rather limited currently.In this paper,an off-line feedrate scheduling method of dual NURBS curve is presented with geometric and kinematical constraints.For a given dual parametric curve,the feedrates of sampling points are first scheduled sequent with confined feedrate of cutter tip and machine pivot,chord error,normal acceleration and angular feedrate.Then,the feedrate profiles of angular feed acceleration sensitive regions of the path are adjusted using a bi-directional scanning algorithm.After that,a linear programming method is used to adjust the feedrate profiles of linear feed acceleration sensitive regions and control the linear feed acceleration of both cutter tip and machine pivot within preset values.Further,a NURBS curve is used to fit the feedrates of sampling points.Finally,illustrative examples are carried out to validate the feasibility of the proposed feedrate scheduling method.The results show that the proposed method has the ability of effectively controlling the angular feed characters of cutter axis as well as the chord error and linear feed characters of cutter tip and machine pivot,and it has potential to be used in high accuracy and high quality five-axis machining.
