Discrete-time stabilization of a PVTOL without roll angle and velocities measurement

This paper studies the discrete-time stabilization of a planar vertical take off and landing aircraft (PVTOL). A Luenberger-type observer is proposed and a sufficient condition on the sampling period is obtained such that the error observer convergence rate becomes exponential. The observer requires measurements of the horizontal and vertical coordinates only and estimates the roll angle and the velocities of the PVTOL. A local stabilizer which makes use of the actual state variables is designed. It is shown that the observer and the stabilizer satisfy a separation principle, in the sense that local stability of the closed loop system is preserved when the actual states are replaced by their estimates. Numerical simulations show that the proposed control strategy is robust in the face of measurements corrupted by noise