Published online by Cambridge University Press: 04 July 2016
This paper addresses the problem of limit-cycle taming,which is defined in this paper as the use ofnonlinear control laws to ensure that thelimit-cycle behaviour of the system beyond thestability boundary is of a benign rather than adestructive nature. Specifically, we consider aone-parameter (denoted by λ) autonomous dynamicsystem having algebraic nonlinearities. We assumethat the system has a stable solution, x = 0, for λ< λ0, and experiences a Hopfbifurcation at λ = λ0. Using a singularperturbation analysis about the stability boundary,it is shown that, using a simple nonlinear controllaw, limit-cycle taming is always possible in theneighbourhood of a Hopf bifurcation. The controlsystem proposed for limit-cycle taming is fullynonlinear, and therefore does not affect the linearbehaviour of the system (in particular its stabilitycharacteristics). Hence, limit-cycle taming may beused in conjunction with a standard linear activecontrol (e.g. use of linear active control toincrease the stability boundary). Applications ofthe theory to the problem of flutter arepresented.
Assistant Professor, Dipartimento Aerospaziale,via Eudossiana 16, 00184 Roma
Professor, Dipartimento di Meccanica eAutomatica, via C. Segre 60, 00146 Roma