Passivity based controller for underactuated PVTOL system

This paper proposes a control law for Planar Vertical Take Off and Landing (PVTOL) system based on feedback passivation method. The PVTOL system is a benchmark control system problem which embodies in itself many control theoretic challenges due to its nonlinear and underactuaed dynamics. Trajectory tracking of PVTOL system with its roll angle control is investigated in the paper. Stability of the PVTOL roll angle is ensured by the property that the equilibrium point of a passive system always remains stable. The equivalence of PVTOL dynamics with the pendulum dynamics is exploited to design a simple passivity based feedback controller. The proposed framework interprets PVTOL dynamics as pendulum dynamics and integrator systems whose interconnection can be made passive under the action of the designed control law. The forces exerted by the actuators can be synthesized from the control law.