CLF based design for attitude control of VTOL-UAVs: An inverse optimal control approach

This paper presents the development of a quaternion-based nonlinear control for the attitude stabilization of VTOL-UAVs. Firstly, it is proved the existence of a Control Lyapunov Function (CLF). Unlike some previously proposed schemes, the aim of this paper is to propose an optimal control using the relationship between Sontag's Formula and optimal control problem. The control law ensures the asymptotic stability of the closed-loop system to the desired attitude. The approach is validated in real-time using a quadrotor mini-helicopter.