In this paper we arrange the faults ordinarily occured in multi-variable control systems under two cate-gories:(1)invalidity of ith sensor,(2)invalidity of jth actuating mechanism.

• 本文把多变量控制系统常出现的故障分为两类:1)第 i 个回路中传感器失效; 2)第 j 个回路中执行机构失效。