A UTONOMOUS S YSTEMS L AB A UTONOMOUS S YSTEMS L AB Design of Solar Powered Airplanes for Continuous Flight André Noth Doctoral Exam – September 30, 2008 Autonomous Systems Lab ETH Zentrum http://www.sky-sailor.ethz.ch/ Tannenstrasse 3, CLA E-mail: andre.noth@a3.epfl.ch 8092 Zürich, Switzerland 1/30
Outline • Introduction • Design Methodology • Sky-Sailor Design • Sky-Sailor Prototype • Scaling • Conclusion André Noth Phd Defense Autonomous Systems Lab ETH Zürich, 24.09.08 1/30
Motivations & Objective • Project started with an ESA feasibility study Introduction Mars exploration � Motivations Satellites + extensive coverage, good resolution � History of Solar Flight � State of the Art - place of interest not freely selectable � Contributions ? Design Methodology Gap for systems with + high-resolution imagery Sky-Sailor Design + extensive & selectable coverage Sky-Sailor Prototype Scaling Rovers + excellent resolution, ground interaction Conclusion - reduced range, limited by terrain � Study the feasibility of solar powered flight on Mars � Develop and realize a fully functional prototype on Earth and demonstrate continuous flight André Noth Phd Defense Autonomous Systems Lab ETH Zürich, 24.09.08 2/30
History of Solar Flight • Started in 1974 • 90 solar powered airplanes listed from 1974 to 2008 Introduction � Motivations � History of Solar Flight Gossamer Penguin (1980) Sunseeker (1990) Solong (2005) Sunrise (1974) � State of the Art 1 st manned solar 1 st continuous flight, manned, crossed 1 st solar powered flight � Contributions powered flight the USA in 21 flight used thermals Design Methodology Sky-Sailor Design Sky-Sailor Prototype Scaling Conclusion 80’s 2000’s 70’s 90’s Solar Riser (1979) Solar Challenger (1981) Helios (1999) Zephyr (2005) manned, battery solar manned, channel umanned, flew at umanned, flew 83h André Noth charged for short flights crossing > 29’000 m Phd Defense Autonomous Systems Lab ETH Zürich, 24.09.08 3/30
State of the art Many solar airplanes in History � … but no clear design methodologies explained � anyway useful practical papers on case studies Introduction � Motivations [ BOUCHER79, MACCREADY83, COLELLA94 ] � History of Solar Flight � State of the Art [ULM96,BRUSS91] � Contributions Design Methodology Many design methodologies… Sky-Sailor Design � … but rarely validated with a prototype [REHMET97, WEIDER06] Sky-Sailor Prototype Scaling � very often nice design methods Conclusion [IRVING74, YOUNGBLOOD82, BAILEY92] but based on weak models for: • Weight prediction design method • Efficiencies � ends with irrealistic designs math. models [RIZZO08, ROMEO04] André Noth Phd Defense Autonomous Systems Lab ETH Zürich, 24.09.08 4/30
Contributions Design methodology • – Simplicity Introduction � Motivations – Large design space � History of Solar Flight � State of the Art – Concrete and experienced based � Contributions Design Methodology – Flexible and versatile Sky-Sailor Design Sky-Sailor Prototype Scaling • Theory validation with a prototype Conclusion – Achieve > 24h flight – Autonomous control Draw up a state of the art on solar aviation • – History André Noth – Publications Phd Defense Autonomous Systems Lab ETH Zürich, 24.09.08 5/30
Design Methodology Introduction Design Methodology � Required Energy � Solar Energy � Weight Models � Resolution Sky-Sailor Design Sky-Sailor Prototype Scaling Conclusion André Noth Phd Defense Autonomous Systems Lab ETH Zürich, 24.09.08 6/30
Design Methodology Energy balance Introduction Design Methodology � Required Energy � Solar Energy � Weight Models � Resolution Sky-Sailor Design Sky-Sailor Prototype Scaling Conclusion Weight balance Lift L Drag D Thrust T Weight mg André Noth Phd Defense Autonomous Systems Lab ETH Zürich, 24.09.08 6/30
Methodology • Sizing the airplane : hen & egg problem Introduction Airplane Parts Weight balance Design Methodology • Solar cells � Required Energy • Battery � Solar Energy ? • Airframe � Weight Models • Payload � Resolution Aerodynamics & flight conditions •… Sky-Sailor Design � Total weight � Level Flight Power Sky-Sailor Prototype Scaling Conclusion Energy balance • This loop can be solved: A A Iteratively (trying existing components, refining the design) B B Analytically (using mathematic models of the components) André Noth Phd Defense � Allows to establish some general design principles Autonomous Systems Lab ETH Zürich, 24.09.08 7/30
Required Energy • Equilibrium at steady level flight ρ = = 2 L mg C Sv 3 C ( mg ) 2 L = = 2 Introduction D P Dv ρ level 3/2 ρ C S Design Methodology L = = 2 D T C Sv � Required Energy D 2 � Solar Energy � Weight Models � Resolution • Power required Sky-Sailor Design η η η η Sky-Sailor Prototype ctrl mot grb plr 1 = P P Scaling P η η η η electot level level Conclusion ctrl mot grb plr P electot 1 ( + + + P P P P ) av pld η av pld η bec bec • Daily energy required ⎛ ⎞ T = + ⎜ ⎟ night E P T André Noth ⎜ ⎟ η η elec tot elec tot day ⎝ ⎠ Phd Defense chrg dchrg Autonomous Systems Lab ETH Zürich, 24.09.08 8/30
Required Energy Introduction Design Methodology � Required Energy � Solar Energy � Weight Models � Resolution Sky-Sailor Design Sky-Sailor Prototype Scaling Conclusion André Noth Phd Defense Autonomous Systems Lab ETH Zürich, 24.09.08 8/30
Solar Energy • Daily average solar irradiance – Irradiance ~ cosine I T Introduction = η max day E π Design Methodology day density wthr / 2 � Required Energy – I max T day = f(date, location, weather) � Solar Energy � Weight Models � Resolution Sky-Sailor Design • Daily energy obtained Sky-Sailor Prototype = A η η η Scaling E E A E E electot day density sc sc cbr mppt Conclusion sc electot day density η η η sc cbr mppt • Daily energy required = Daily energy obtained � We compute A sc André Noth Phd Defense Autonomous Systems Lab ETH Zürich, 24.09.08 9/30
Required Energy Introduction Design Methodology � Required Energy � Solar Energy � Weight Models � Resolution Sky-Sailor Design Sky-Sailor Prototype Scaling Conclusion André Noth Phd Defense Autonomous Systems Lab ETH Zürich, 24.09.08 9/30
Weight Prediction Models • Fixed Masses • Payload m pld Introduction • Avionic System (Autopilot) Design Methodology m av � Required Energy � Solar Energy • Airplane Structure � Weight Models � Resolution – In the literature Sky-Sailor Design Sky-Sailor Prototype = ⋅ • [BRANDT95, GUGLIERI96,…] consider W k S Scaling af Conclusion � valid locally • [HALL68] calculated all airframe elements separately � complex, only valid for 1000-3000 lbs airplanes = • [STENDER69] proposed 0.311 0.778 0.467 W 8.763 n S AR af � very widely adopted = � adapted by [RIZZO04] to UAV 0.656 0.651 W 15.19 S AR af André Noth Phd Defense Autonomous Systems Lab ETH Zürich, 24.09.08 10/30
Weight Prediction Models • Verification of these models – Database of 415 sailplane Introduction – Structure Weight vs Area Design Methodology � Models don’t fit well � Required Energy � Solar Energy � Weight Models � Resolution optimistic Sky-Sailor Design Sky-Sailor Prototype • New model proposed Scaling pessimistic – Same equation, new coef. Conclusion – Least square method fit – Data set divided in two – 5 iterations = 5 qualities – Best 5% model: Keywords: Wing weight to area , wing area as a function AR − = ⋅ 3.10 0.25 W 0.44 b of structural weight, great flight diagram, Tennekes, wing af mass to area, mass to surface, area to mass, surface to André Noth mass. Phd Defense Autonomous Systems Lab ETH Zürich, 24.09.08 11/30
Weight Prediction Models Overview Biologists already studied flying in nature to extract tendencies Introduction [TENNEKES92] presented the Design Methodology « Great Flight Diagram » � Required Energy Clear cubic tendancy � Solar Energy � Weight Models � Resolution Our model is // to Tennekes curve Sky-Sailor Design Sky-Sailor Prototype [STENDER69,RIZZO04] seem Scaling incoherent Conclusion Keywords: Wing weight to area , wing area as a function of structural weight, great flight diagram, Tennekes, wing mass to area, mass to surface, area to mass, surface to mass. André Noth Phd Defense Autonomous Systems Lab ETH Zürich, 24.09.08
Required Energy Introduction Design Methodology � Required Energy � Solar Energy � Weight Models � Resolution Sky-Sailor Design Sky-Sailor Prototype Scaling Conclusion André Noth Phd Defense Autonomous Systems Lab ETH Zürich, 24.09.08 12/30
Recommend
More recommend
