基于奈奎斯特稳定性分析的分散PI控制器设计 其中包括：列主对角占优定理、盖尔圆环定理、 对角优势系统的稳定性仅仅取决于其传递函数的主对角元素等等

-Nyquist stability analysis based on the decentralized PI controller design, including: the column diagonal dominance theorem, Gail circle theorem, diagonal dominant system, the stability of the transfer function only depends on its main diagonal elements, etc. etc.