Nonlinear Interactions between Signals and Parameters in Robust Adaptive Control

Little is known about the bursting phenomenon, present in underexited adaptive control systems. The bulk of the reported analysis of bursting relies on a time-scale decomposition of the adaptive controller closed loop state-space. Much of the bursting cycle (i.e. drift, burst and recovery) occurs beyond the region of the state-space where the decomposition applies. This paper studies the non-linear interactions between the regressor generation and the adaptive algorithm. It brings insight into the tunning of leakage and dead-zones. We profit from the departure from the traditional approach in gaining qualitative insight into this instability mechanism.