Control Law Design for Improving UAV Performance Using Wind Turbulence

Birds and insects frequently use the energy present in the atmosphere to conserve energy. Energy in the form of thermal updrafts is routinely used successfully by pilots of full-scale and model sailplanes. The energy present in atmospheric turbulence, however, has not been utilized to its full potential. This paper deals with the design of simple control laws to extract energy from atmospheric turbulence. A point mass model is used to simulate glider ∞ights through realistic gusts based on the Dryden power spectral density function, and an optimization procedure to design control laws under a stochastic environment is presented. The results show that, for small UAVs, signiflcant energy savings are possible using active control laws. Factors afiecting energy extraction are outlined and issues arising in gust modeling, stochastic optimization, and realistic constraints are addressed.