Local Bézier Transition Method along Continuous Short-line Toolpath

doi:10.3901/JME.2018.19.111

Abstract

Abstract: Linear toolpath, which is in forms of G01 codes, is most popular in practical computer numerical control (CNC) machining area. However, unavoidable velocity and acceleration fluctuations are caused by the linear toolpath discontinuity at corners, leading to machining vibration and poor surface texture. A cubic Bézier curve with four control points is adopted to blend sharp corners. With constrained chord error, the curvature extreme is proves to occur at the middle of transition curves and can be calculated analytically. In addition, optimal curvature extreme is searched to enhance machining efficiency. In motion planning process, a look-ahead methodology is utilized to determine the reachable feedrate at curvature extreme points. Afterwards, a jerk-continuous feedrate scheduling scheme is developed. Finally, tracking and machining experiments are conducted to demonstrate the efficiency, contour performance and machining quality of the proposed method compared to previous methods.

Key words: Bézier curve, feedrate scheduling, jerk-continuous, local transition methods

CLC Number:

TG156

ZHANG Yong, YE Peiqing, XIAO Jianxin, ZHANG Hui. Local Bézier Transition Method along Continuous Short-line Toolpath[J]. Journal of Mechanical Engineering, 2018, 54(19): 111-120.

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