Nonlinear Predictive Control of Tethered UAVs

This work addresses the problem of setpoint tracking for tethered unmanned aerial vehicle (UAV) systems. Previous works have either used simplified models for the complex tension constraint to ensure a taut cable or proposed non-optimal strategies applicable to limited setpoints. The approach proposed here is based on the nonlinear model predictive control (nMPC), where the subtleties of implementing such a strategy for this nonlinear dynamic system with nonlinear constraints are addressed. Proposed control scheme is also complemented by a pre-stabilizing nonlinear control law to achieve a design that handles constraints and stabilizes the closed-loop system. We compare the results of the augmented pre-stabilized MPC scheme with results from the literature, as well as with the nominal nMPC case.