Event-triggered control is a resource-aware sampling strategy that updates the control value only when a certain condition is satisfied, which denotes event instants. Such a technique allows to reduce the control computational cost and communications. In this paper, a quaternion-based feedback is developed for event-triggered attitude stabilization of a quadrotor mini-helicopter. The feedback is derived from the universal formula for event-triggered stabilization of general nonlinear systems affine in the control. The proposed feedback ensures the asymptotic stability to the desired attitude. Real-time experiments are carried out in order to show the convergence of the quadrotor states to the desired attitude as well as the robustness with respect to external disturbances. Results show that the proposed control can reduce by 80 % the communications of the embedded system without sacrificing performance of the whole system. To the best of the authors' knowledge, this is the first time that a nonlinear event-triggered controller is experimentally applied to the attitude stabilization of an unmanned aircraft system.

The present paper investigates the consensus control of a Multi-Agent System (MAS) composed by Vertical Take-off and Landing (VTOL) rotorcrafts subject to aerodynamic disturbances. Initially, the attitude's VTOLs model based on quaternion formalism is detailed to subsequently derive the corresponding control law. Likewise, the MAS translational dynamics is extended to entail the airframe's aerodynamics. In order to achieve the consensus objective, a robust adaptive event-triggered sliding-mode control (SMC) is synthesized considering a leader-follower scheme guaranteeing Lyapunov's closed-loop stability and avoiding the Zeno behavior. Results from an extensive simulation stage witness the effectiveness of the proposed control scheme. The latter allows to fulfill the collective consensus and leader's trajectory tracking objectives in presence of unknown disturbances while keeping a reduced computational cost.

In the present work, an adaptive backstepping algorithm is developed in order to counteract the effects of disturbances. These disturbances are modeled as a constant force in the translational model part and as a constant torque in the orientation model part. We make the deduction of the mathematical expression for the proposed control algorithm and also we show its performance in simulation. Additionally, we include some experiments for validating the results obtained via simulation.