ON THE CONTINUITY PROPERTIES OF THE H
H∞最优性能指标的连续性问题

The discontinuity of γopt as presented by Gahinet is analysed in this paper. It is pointed out that this phenomenon is caused by the different existing conditions for H∞ controllers and/or the possibility of pole/zero cancellation in the design. It is also pointed out that the computing method itself can not change the essential difficulties in design. For singular H∞ problem, a dedicated approach is still needed.