Combined plant and controller performance analysis and optimization for an energy-harvesting tethered wing

Abstract

This paper presents a combined plant and controller analysis and optimization for a tethered rigid wing with on-board rotors, flying in crosswind patterns. Specifically, we use a 3-D model of the tethered wing to assess the influence of critical design parameters on both quality of flight and energy generation performance, as quantified by the “Loyd Factor” [1], which compares energy generation performance to a theoretical upper bound established by Miles Loyd [2]. Recognizing that the optimal performance occurs when the system is on the verge of instability, we demonstrate how a combined optimization of the plant and controller can aid in further pushing the boundaries of the system. The results of this combined optimization show a critical trade-off between robustness and energy generation performance, wherein the attainment of peak performance not only requires operation on the verge of instability but also results in the shrinking of the set of parameters for which the system is stable.