中文说明： pca是很常见的多元统计方法，利用pca的两个统计量进行故障诊断是一种很常见的诊断方法，该代码利用了多个置信度设置了不同的控制限，同时对其中的一个故障点进行了贡献图分析其故障原因。
English Description：
PCA is a very common multivariate statistical method, and it is a very common diagnostic method to use two statistics of PCA for fault diagnosis. The code uses multiple confidence to set different control limits, and at the same time, it makes contribution graph for one of the fault points to analyze the fault reason.