美国麻省理工大学：Estimation and Control of Aerospace Systems（航空系统的估计与控制）：hO3

Handout 3: Gain and Phase Margins for unstable systems Eric Feron Feb 9, 2004 Gain and Phase Margins exist for all systems, including the 1 unstable ones Example1: H(s) = 1 ? s/1 Sketch the Bode plot (Gain and Phase) to the left of next page. Sketch root-locus to the right of the page, above the Nyquist plot. Phase margin for K = ?1.3 is 1 2 s 2 + 0.2s + 3 H(s) = 3(s ? 0.1)(s 2 + 0.2s + 1) Figure 1: 1 cm of space 3