High-gain control without identification: a survey

Three related but distinct scenarios for tracking control of uncertain systems are reviewed: asymptotic tracking, approximate tracking with prescribed asymptotic error bound, tracking with prescribed transient behaviour. A variety of system classes are considered, ranging from finite‐dimensional linear minimum‐phase systems to nonlinear, infinite‐dimensional systems described by functional differential equations. These classes are determined only by structural assumptions, such as stable zero dynamics and known relative degree. The objective is a single (and simple) control structure which is effective for every member of the underlying system class: no attempt is made to identify the particular system being controlled. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)