Linear sensitivity analysis applied to a two-loop system with feedback variations†

Abstract

Abstract The objective of this investigation is to determine correlation between engineering observations of system sensitivity compared to analytically computed sensitivity parameters. A two-loop system representative of an aircraft altitude control system, designed by the compensation parameter variation technique is presented as an example. Sensitivity observations are made of the behaviour of the system poles in the complex plane. For the inner loop reasonable correlation was found between the observed pole sensitivities and the computed Bode pole sensitivities. For the outer-loop system also the computed Bode pole sensitivities showed good correlation with the observed outer-loop pole sensitivities, but not with the observed output sensitivities.