Stabilization and passification of uncertain systems via static output feedback

Control of systems with time-varying dynamical characteristics impose either a conservative time-invariant control strategy that should hold for all time instants or to adopt some adaptive scheme. One of such, called simple adaptive control, is particularly appropriate for control applications such as flexible aircrafts or other fast varying processes. Indeed, it does not need any real-time estimation of time-varying parameters but adapts based on the unique sensors measurements. Yet, this control strategy, also called passivity-based adaptive control, needs to be applied for the system to be passifiable. Or at least it needs to exhibit a linear combination of the inputs and outputs such that this property holds. The paper is devoted to the search of such linear combinations with practical efficient algorithms. Results are discussed in detail for an uncertain time-varying aircraft control example.