Dual-Bézier path smoothing and interpolation for five-axis linear tool path in workpiece coordinate system
Dual-Bézier path smoothing and interpolation for five-axis linear tool path in workpiece coordinate system
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DOI：
10.1177/1687814015595211
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发表时间：
2015-07
影响因子：
2.1
通讯作者：
Yongqiao Jin;Q. Bi;Yuhan Wang
中科院分区：
文献类型：
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作者：
Yongqiao Jin;Q. Bi;Yuhan Wang
由连续的短线段（G01块）组成的刀具轨迹仍然是五轴加工中广泛采用的刀具轨迹表示形式。直线刀轨的固有缺点是刀轨转角处的一阶不连续，这是实现高速高精度加工的瓶颈。提出了一种工件坐标系下五轴直线刀具轨迹的双bsamizier路径平滑算法。我们的方法包括三个步骤。首先，引入角点误差分布模型，将给定公差分配给平滑逼近误差约束和弦点误差约束，保证插值轨迹误差在给定公差范围内；其次，采用双G2连续三次bsamizier曲线对工件坐标系下直线刀具轨迹的分段结点进行光滑处理。一个三次bsamzier曲线用于刀尖点路径的圆角，另一个bsamzier曲线用于刀轴点路径的圆角。该算法考虑了逼近误差约束、参数化同步约束和连续曲率约束等条件。因此，在新路径上切线和曲率的连续性都得到了保证。第三，引入自适应馈电调度方法对新路径进行插值。通过仿真和实验验证了该方法在五轴刀具轨迹平滑、速度平滑和轨迹精度控制方面的有效性。
The tool path composed of consecutive short linear segments (G01 blocks) is still the widespread tool path representation form in five-axis machining. The inherent shortcoming of linear tool path is first-order discontinuity at the corner, which is the bottleneck to achieve high-speed and high-accuracy machining. In this article, a dual-Bézier path smoothing algorithm for five-axis linear tool path in workpiece coordinate system is proposed. There are three steps involved in our method. First, the corner error distribution model is introduced to assign the given tolerance to the smoothing approximation error constraint and the chord error constraint to ensure the interpolation trajectory error within the given tolerance. Second, segment junctions of the linear tool path in workpiece coordinate system are smoothed by double G2 continuous cubic Bézier curves. One cubic Bézier curve is used to round the corner of the tool tip point path, and the other Bézier curve is used to round the corner of the tool axis point path. This algorithm takes the conditions of approximation error constraint, the parameterized synchronization constraint, and continuous curvature constraint into consideration. Hence, the tangency and curvature continuities are both guaranteed in the new path. Third, an adaptive feedrate scheduling method is introduced to interpolate the new path. Simulation and experiment are performed to verify the effectiveness of the proposed method in five-axis tool path smoothing, speed smoothing, and trajectory accuracy controlling.