ABSTRACT
CHAPTERS 2, 3, and 4 described various techniques for the control of systemswith vibratory modes. These techniques are model-based and are often sensitive to errors in model parameters. In Chapter 2, the sensitivity of the pole-zero cancelation constraints with respect to the uncertain model parameters was used to design filters/controllers. The resulting control profiles are robust around the nominal model of the system. Thus, for shaping the reference input to a system with modeling errors, it was shown that by cascading multiple instances of the time-delay filter designed to cancel the poles of the system, resulted in a filter that was insensitive to error in modeled natural frequency and damping ratio. The idea of locating multiple zeros of a time-delay filter at the estimated location of the poles of the system has been exploited to design robust time-optimal control [1,2], robust fuel/time optimal control [3], fuel constrained time-optimal control [4], and so forth, as shown in Chapter 4. The concept of using terminal state sensitivities with respect to the uncertain model parameters can be extended to nonlinear systems undergoing rest-to-rest maneuver, and has been shown to result in robust control by Liu and Singh [5].
