针对一种简易链长测量法的误差分析及改进方案

Error analysis and optimization for a simplified chain length measurement method

目前在链磨损试验中用于检验延伸率的一种简易链长测量方法在其计算过程中存在较大理论误差,面对日益多样化的测试任务不具有普遍有效性,有必要对其改进.将基于中心距测量的测量系统拆分成与中心距对应的绷直链部分和与测量设备接触的弯折链部分,对测量系统进行数学建模,同时考虑具体的测量时刻对测量误差的影响,对误差展开较为全面的分析,结果发现误差主要来源于用弧长代替折线的近似手段.随后提出的一种基于理论节距的改进算法经过理论分析和对照测试标准的计算证明,在整体误差上比原算法小1个数量级,能显著地提高简易测量法的精度以满足工程要求,拓展了其有效应用领域.此外,结合设备的误差分析还以提高精度为目标对测试工具的设计提出了建议.

Simplified chain length measurement method currently used in chain wear test for elon- gation calculation has relatively large theoretical error which cannot guarantee the effectiveness considering increased types of measurement requirement. The measurement system based on axial distance was divided into two parts, where the part of chain was straight-tight or bended. Then mathematical models were created for the system considering the influence of measurement timing on error. Based on error analysis, the approximation of polylines with arc was proved to be the main cause of the measurement error. A new calculation method with smaller error by an order of magnitude was suggested, which made the simplified measurement method meet the general requirement on accuracy. It was also proved to be correct by validation with test standards. The improvement on calculation alone is meaningful in specific application areas, and the accuracy can be further increased by applying error analysis on equipment design.