H_∞设计:两块还是三块问题

H_∞ control: 2-block or 3-block problems

讨论了Ｈ∞混合灵敏度问题，指出两块的 Ｓ／Ｔ问题可满足一般的鲁棒设计要求，但往往不能满足标准Ｈ∞控制问题的秩的条件，而且所得到的控制器的高频段具有较高的增益，所以建议采用三块问题来进行设计，指出虽有第三块的介入，但在主要频段上仍要雏持按两块问题来设计的特点。文中给出了磁悬浮系统Ｈ∞控制器设计的例子。

The H∞ mixed sensitivity problem is discussed in this paper. It is pointed out that the 2-block mixed SIT problem is suitable for robust design. But, in general, the S/T design can not meet the rank conditions of the standard H∞control problem. In addition, the controller obtained often has high gain in the high frequency range. So, it is recommended to use S/KS/T in design. The introduction of the third block must preserve the 2-block design character over the main bandwidth. An example of H∞ controller design for a MagLev system is illustrated.