A Feedrate Planning Method for the NURBS Curve in CNC Machining Based on the Critical Constraint Curve

The curvature of the NURBS curve varies along its trajectory, therefore, the commonly used feedrate-planning method, which based on the acceleration/deceleration (Acc/Dec) model, is difficult to be directly applied in CNC machining of a NURBS curve. To address this problem, a feedrate-planning metho...

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Bibliographic Details
Published inApplied sciences Vol. 11; no. 11; p. 4959
Main Authors Guo, Peng, Wu, Yijie, Yang, Guang, Shen, Zhebin, Zhang, Haorong, Zhang, Peng, Lou, Fei, Li, Hengbo
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.06.2021
Subjects
Acceleration
acceleration/deceleration
Computer applications
Curvature
Deceleration
Efficiency
feedrate planning
feedrate-constraint value
Kinematics
Machining
NURBS
Planning
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Summary:The curvature of the NURBS curve varies along its trajectory, therefore, the commonly used feedrate-planning method, which based on the acceleration/deceleration (Acc/Dec) model, is difficult to be directly applied in CNC machining of a NURBS curve. To address this problem, a feedrate-planning method based on the critical constraint curve of the feedrate (CCC) is proposed. Firstly, the problems of existing feedrate-planning methods and their causes are analyzed. Secondly, by considering both the curvature constraint and the kinematic constraint during the Acc/Dec process, the concept of CCC which represents the relationship between the critical feedrate-constraint value and the arc length is proposed. Then the CCC of a NURBS curve is constructed, and it has a concise expression conforming to the Acc/Dec model. Finally, a feedrate-planning method of a NURBS curve based on CCC and the Acc/Dec model is established. In the simulation, a comparison between the proposed method and the conventional feedrate-planning method is performed, and the results show that, the proposed method can reduce the Acc/Dec time by over 40%, while little computational burden being added. The machining experimental results validate the real-time performance and stability of the proposed method, and also the machining quality is verified. The proposed method offers an effective feedrate-planning strategy for a NURBS curve in CNC machining.
ISSN:2076-3417
2076-3417
DOI:10.3390/app11114959