Motion Error Analysis and Modeling Technology of CNC Camshaft Grinder
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摘要: 为了对某数控凸轮轴磨床的运动误差进行分析和建模,分析研究了各运动部件间运动形式和误差类型,运用相邻体坐标系间的运动变化来表达2相邻体之间的运动情况,建立了相邻体之间的理想运动方程和有误差情况下的实际运动方程. 将相邻体间的实际运动方程进一步推广到任意低序体阵列分析当中,为研究多分支数控凸轮轴磨床误差建模提供理论基础. 将复杂的多分支链数控凸轮轴磨床抽象为简单的多体系统,对各运动部件建立相应的体坐标系和运动参考坐标系,求出相邻体间对应的变换矩阵. 最后,将机床运动部件划分为“工件-床身”和“砂轮-床身”2条运动链,提出了有误差影响情况下实现精密加工约束条件方程为Pw=Pt,且对该方程进行了求解,为数控凸轮轴磨床误差补偿的研究提供了必要条件. 结果表明:误差补偿后的机床加工精度显著提高.Abstract: Taking certain CNC camshaft grinder as the subject, its motion error analysis and modeling were studied. The movement forms and types of errors between the moving parts were analyzed, the movement between coordinate systems of the adjacent bodies was used to express the movement between the two adjacent bodies, and the ideal motion equation and actual motion equation in case of errors between the adjacent bodies were set up. Actual motion equation between adjacent bodies was made and further extended to analyze arbitrary low-order body arrays, which provides a theoretical basis for studying the multi-branch CNC camshaft grinding machine error modeling. Complex multi-branch chain CNC camshaft grinder simplified was made as a simple multibody system, and corresponding body coordinate systems and motion reference coordinate systems for moving parts were established to calculate the corresponding transformation matrix between adjacent bodies. Moving parts of the machine were divided into “workpieces-bed” and “wheel-bed” two kinematic chains. The precision constraint equation of the machine is Pw=Pt in case of using errors influence, and the constraint equation was solved. It provides necessary conditions for study of CNC camshaft grinder error compensation. Results show that the machine precision is significantly improved after error compensation.
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Key words:
- CNC camshaft grinder /
- error analysis /
- multibody system /
- motion relationship /
- error modeling
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表 1 数控凸轮轴磨床几何误差参数
Table 1. Geometric parameters of CNC camshaft grinder
误差性质 线位移误差 角位移误差 误差方向 沿x、沿y、沿z 绕x、绕y、绕z 沿x平移 δx(x)、δy(x)、δz(x) εx(x)、εy(x) 、z(x) 沿z平移 δx(z)、δy(z)、δz(z) εx(z)、εy(z)、εz(z) 绕c转动 δx(c)、δy(c)、δz(c) εx(c)、εy(c)、εz(c) 交叉 εxz、εxc、εzc 表 2 数控凸轮轴磨床拓扑结构的低序体阵列
Table 2. Number array of low-order body for CNC camshaft grinder
L0(k) 1 2 3 4 5 6 7 8 L1(k) 0 1 2 3 4 1 6 7 L2(k) 0 0 1 2 3 0 1 6 L3(k) 0 0 0 1 2 0 0 1 L4(k) 0 0 0 0 1 0 0 0 L5(k) 0 0 0 0 0 0 0 0 -
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