A Nonlinear Strategy to Control Unstable Underactuated Mechanical Systems with Underactuation > 1 . Applications to Control Augmentations †

The essence of the complex dynamics originated by the interaction between the pilot–&–aircraft can be captured on labs, by means of unstable–underactuated mechanical systems. Thus, the unactuated links describe the autonomous aircraft dynamics (flight control system) and the actuated the manual one (pilot). It is well–known that, in some flight conditions, the pilot–&–aircraft interaction can render the system unstable. Thus, a standard solution of designing a decoupled dynamics between the flight control system and the pilot, either becomes useless or restrict the maneuverability unnecessarily. The nonlinear and compact strategy proposed here can pave the way to a less conservative (or even safety) solution in aircraft implementation. Successful experiments on the Furuta’s pendulum are reported and to the best of authors’ knowledge it has the largest attraction basin experimentally tested so far.