一种基于最小二乘圆动态特征分析的圆度误差稳健评估方法

摘要

针对现有圆形工件圆度误差测量与评估方法大多仅从整圆全局的角度出发,而对局部圆度动态误差特性关注不足的问题,设计了一种基于局部最小二乘圆参数动态特征的工件圆度高稳健评估方法.首先,通过随机选取均匀分布的固定数目原始点进行初始圆参数拟合,在初始圆参数约束下对原始数据点进行划分;接下来,对每一个划分结合随机采样一致性(RANSAC)技术实现局部圆度参数的动态计算;最终在局部圆参数统计特征的支持下实现了局部和全局圆度误差的评估.实验结果表明:所提方法能够稳定有效地实现工件圆度的评估.%Considering the fact that existing circular workpieces'' roundness error measurement and evaluation mostly starts with a global manner for the measured circle and pay less attention to the dynamic error characteristics of local roundness, a robust roundness evaluation method for circular workpieces based on local least square circle fitting was proposed, in which, having equally-distributed initial points of fixed number selected randomly for parameter fitting and then having all data points divided into several local sections by employing initial entire circle parameters;and then for each local section, having random sampling and consensus (RANSAC) technology adopted to estimate dynamic local circle parameters and finally, having local and entire circle errors evaluated under the support of statistical feature of local circle parameters.Experiential results illustrate that the proposed method can stably perform robust roundness evaluation efficiently of the circular workpiece.