基于相似材料模拟实验平台的坐标框架构建及精度分析

    Construction method of coordinate frame based on similar material simulation experiment platform and precision analysis

    • 摘要: 相似材料模拟实验中,科学、快速、准确地获取研究对象的位移场信息是实验的重要环节之一,而构建高精度的局部坐标系是获取目标点位空间信息的基础。基于此,提出了一种实用的高精度的相似材料模拟实验平台坐标框架的构建方法,建立了坐标框架误差模型,得出了坐标框架点位中误差计算公式,并通过设计的现场实验对模型进行了分析和验证。结果表明,量距误差分别随尺长改正值和温度改正值的增加而线性增加。在不同仪器测角精度下,坐标框架点位中误差随尺长改正值和温度的增加都呈现先减小后增大的趋势,都存在极小值,并且随着仪器精度的提高,点位中误差逐渐减小。计算得到坐标框架上两待定点点位中误差理论值分别为±0.633 mm、±0.558 mm,而通过现场实验和分析计算,对应两点的实际点位中误差分别为±0.409 mm、±280 mm,实测精度值优于理论计算值。

       

      Abstract: In similar material simulation experiment, it is an important process to obtain the displacement field of the subject investigated scientifically, fast and precisely, and the construction of local coordinate system with high precision is the foundation of obtaining spatial information of subject points.Based on this, this paper puts forward a practical construction method of coordinate frame in similar material simulation experimental platform, meanwhile establishes the coordinate frame error model, obtaines the calculation formula of the point mean square error in the coordinate frame, and analyzes and validates the model through the design of the field experiment.The results show that measuring error increases linearly with the increase of length correction and temperature, respectively.In different measuring precisions of angle, the point mean square error of the coordinate frame, along with the increase of length correction or temperature, has a trend of increase with decrease at first and has its minimum, and the point mean square error decreases with the improvement of instrument measuring precision.The calculated theoretical mean square errors of intending-set points in the coordinate frame are respectively ±0.633 mm and ±0.558 mm.Nevertheless, mean square errors of corresponding points of the field experiment are ±0.409 mm and ±280 mm, which are better than the theoretical calculated values.

       

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