用直接线性变换算法测量门式起重机主梁挠度

Measurement of main girder deflection of gantry crane by direct linear transformation algorithm

门式起重机的主梁挠度测量是关键的结构监测任务,其重要性不可忽视。现有主梁挠度测量方法需停机测量,存在繁琐操作、对离群点极为敏感等问题,致使测量不准确。文中提出一种基于直接线性变换的主梁挠度测量新方法。在传统的直接线性变换算法基础上引入最小化异常值L1范数的目标函数,通过考虑残差和后验方差,采用Soft-IPOD方法求解目标函数,提高对离群点识别和剔除的鲁棒性,有效避免了因离群点导致的挠度测量不准确问题。仿真和现场实验表明,该算法能够准确识别和剔除异常值,挠度测量的精度明显优于传统方法,平均误差小于1.5 mm,相对误差小于5%。该方法在计算速度方面表现出色,速度较基于RANSAC的直接线性变换算法提高近20倍。在工程实验中,该方法展现出了优异的性能,为门式起重机主梁挠度的快速、准确测量提供了一种可行的解决方案。

The deflection measurement of main girder of gantry crane is a key structural monitoring project.The existing deflection measurement methods of main girder need to be measured after shutdown,which have some problems such as cumbersome operation and extremely sensitive to outliers,resulting in inaccurate measurement.In this paper,a new method for measuring the deflection of main girder based on direct linear transformation is proposed.Based on the traditional direct linear transformation algorithm,the objective function of minimizing the L1 norm of outliers is introduced.By considering the residual and posterior variance,the objective function is solved by using the Soft-IPOD method,which improves the robustness of outlier identification and elimination and effectively avoids the inaccuracy of deflection measurement caused by outliers.Results of simulation and field experiments show that the algorithm can accurately identify and reject outliers,and the accuracy of deflection measurement is obviously better than that of traditional methods,with an average error of less than 1.5 mm and a relative error of less than 5%.This method has excellent performance in computing speed,which is nearly 20 times faster than the direct linear transformation algorithm based on RANSAC.In the engineering experiment,this method shows excellent performance and provides a feasible solution for the rapid and accurate measurement of the deflection of the main beam of the gantry crane.