Resonance seeking control in an event-triggered discrete-time domain

Resonance tracking control of oscillatory plants whose natural frequency is unknown is investigated from a Lyapunov stability perspective. In particular, an event-triggered discrete-time system is investigated for this purpose. The proposed resonance tuner is time-synchronized with periodic sampling of the harmonic plant´s output to ensure that an analytical relationship exists between the period of the driving squarewave and the tracking error. This relation defines a class of discrete-time nonlinear systems whose origin, is shown to be asymptotically stable.