On the prediction of limit cycle bifurcations in feedback systems

The paper studies the bifurcations of limit cycles for a class of feedback systems depending on a parameter. The use of harmonic balance methods in a suitable frequency band of the system leads to conditions in terms of simple equations which give a complete picture of every kind of generic bifurcation. Examples of application concerning the prediction of cyclic fold and Neimark-Sacker bifurcations are reported.