美国麻省理工大学：Estimation and Control of Aerospace Systems（航空系统的估计与控制）：l22

Handout 15: Describing functions, Introduction Eric Feron March 31, 2004 General Philosophy General reponse of arbitrary nonlinear systems is somewhat complicated. We usually know the systems we work with. Work with ?nite families of ’most likely responses’. 1 Typical most likely responses: Sinusoidal Bias - almost ’constant’ signals 2 Typical most likely responses: Slow signals + fast oscillations 3 The ?ltering idea Basic principles for working with ’most likely responses ’Rayleigh-Ritz approximations’ 4