基于马氏距离的最终执行元件功能安全失效表征

Functional safety failure characterization of a final actuator based on Mahalanobis distance

针对现有最终执行元件功能安全失效分析方法未能切实考虑实际工况的不足,提出了一种基于马氏距离的最终执行元件功能安全失效表征方法。预先获取各状态下最终执行元件的工况参数,构建样本空间,计算其中各样本的马氏距离;其次对马氏距离进行Box-Cox变换,使其满足正态分布后,由3σ准则确定各状态的阈值,构建最终执行元件的失效表征模型;最后利用所设计的检测系统检测工况参数,构建样本向量,通过所构建的失效表征模型实现最终执行元件功能安全失效表征。仿真实验和现场实验结果表明,本文方法能够准确识别出最终执行元件的功能安全失效,为其失效分析提供了一种新的方法。

In view of the shortcomings of the existing functional safety failure analysis methods for a final actuator which fail to consider its actual working conditions, this paper proposes a method to characterize the functional safety failure of a final actuator based on Mahalanobis distance. The working condition parameters of the final actuator in each state are obtained in advance, and the sample space is constructed to calculate the Mahalanobis distance for each sample. The Mahalanobis distance is subsequently transformed by Box-Cox to meet the normal distribution, the threshold value of each state is determined by the 3σ-criterion, and a failure characterization model of the final actuator is constructed. Finally, the working condition parameters are obtained by the detection system, and the sample vector is constructed. Based on the model of failure representation, the functional safety failure representation of the final actuator is realized. The results of simulation and field experiments show that this process can identify functional safety failure of a final actuator, and it thus provides a new method for the functional safety failure analysis of a final actuator.