Autonomous hanging tether management and experimentation for an unmanned air?surface vehicle team

The mission of an unmanned air vehicle (UAV) tethered to a small surface (USV) is considered. As opposed the majority existing UAV work, which assumes taut tether, this paper addresses challenge tether management for slack, hanging in dynamic ocean environment up sea state 4 on Douglas scale. A prototype smart reel system UAV–USV team was designed and experimentally validated controlled uncontrolled environments. reference model control based static catenary cable theory extended shown be valid through entire operational envelop. Kalman filter developed fuse slow (4 Hz) differential GPS (dGPS) relative position measurements with fast (100 inertial measurements, output 100 Hz estimate position, velocity, sensor bias. velocity-based gain-scheduled proportional-derivative (PD) controller developed, demonstrated robustness heave, pitch, roll motion USV. Experimental testing surrogate showed successful decoupling heave from altitude indoor environment. Taut control, contrast, exhibited 12 times more tension at compared proposed here. performance tuned feedback minimal deviation during experiments. Indoor flight essentially decoupled USV that UAV; measured deflections matched untethered flight. Outdoor flights effectiveness unknown environment, larger between USV, using dGPS solution measure position. Initial experimental results look promising continued on-water hanging-tether UAV/USV teams.