Attitude tracking control of an airborne wind energy system

Abstract

We consider attitude tracking control for an airborne wind energy system, which generates electricity through a turbine mounted on a tethered glider flying at higher altitude than conventional wind turbines. The airborne wind energy system, which efficiently harnesses energy due to high-speed crosswind motion, consists of a rigid glider (also referred as a rigid kite) and constant length tether connected to the ground. Full aircraft dynamics are modeled including a rotational equation of motion. The resulting dynamical system is an under-actuated mechanical system with only rotational control inputs. We first propose an attitude tracking theorem that provides desired tracking signals for rotational motion. A feedback linearization controller and a real time differentiator are designed and implemented on the full glider dynamics to try to achieve the desired angle of attack and sideslip angle. A comparison study is conducted between a Lyapunov-based and attitude tracking control for the same baseline conditions for the airborne wind energy system.