ABSTRACT
In this chapter, which is based on Szidarovszky and Bahill (1998), we discuss stability. We start by discussing
interior stability, where the stability of the state trajectory or equilibrium state is examined, and then we
discuss exterior stability, in which we guarantee that a bounded input always evokes a bounded output. We
present four techniques for examining interior stability: (1) Lyapunov functions, (2) checking the
boundedness or limit of the fundamental matrix, (3) finding the location of the eigenvalues for state-space
notation, and (4) finding the location of the poles in the complex frequency plane of the closed-loop transfer
function. We present two techniques for examining exterior (or bounded-input/bounded-output [BIBO])
stability (1) use of the weighting pattern of the system and (2) finding the location of the eigenvalues for state-
space notation.
