＠陈庄金￥福州大学机械系１引言一个系统的稳定性品质有许多判断方法，近年来由于鲁棒性研究的深入，奈魁斯特曲线又引起人们的兴趣［１］。一个有实用意义的系统不仅要求开环系统的奈魁斯特曲线Ｌ不包含（－１，０）点，且要求以Ｌ上的点为圆心，以不确定因素ρ为半径画出的奈... @ Chen Zhuang Jin Fuzhou University Department of Mechanical 1 Introduction A system of stability, quality, there are many ways to judge, in recent years due to the study of robustness, Nyquist curve has aroused people’s interest [1]. A practical system not only requires that the Nyquist curve L of the open-loop system does not contain a (-1,0) point, but also requires a point drawn on the point L as the center of the circle and the uncertainty ρ as the radius. ..