Micro air vehicles

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Micro air vehicle : a seminar topic for mechanical/ electrical-electronics.

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Micro air vehicles

  1. 1. Umesh Kumar Meher
  2. 2.  Multi functional, militarily capable, small flight vehicles.  size should be less than15cms.  Reynold’s no < 10^5.  For a Primarily intended and developed for defence applications.
  3. 3.  Keeps security personnel out of harms by providing situational awareness right down to platoon level.  Direct connectivity  Can be individually controlled  Can be used for a wide range of new missions _ (even unthought before!)
  4. 4.  Reconnaissance  Surveillance  Defence applications  Weather forecast  Wildlife study &photography  Crowd control  Targetting  Border surveillance  Traffic monitoring  Tracking criminals & illegal activities  Biochemical sensing  Sesmic detection  inspection of pipes
  5. 5. 1. FLIGHT CONTROL 2. PROPULSION SYSTEM 3. COMMUNICATION SYSTEM 4. GUIDANCE&NAVIGATION
  6. 6.  Completely different aerodynamics due to low Reynold’s number  Reynold’s no:= inertia force/viscous force  Here viscous forces dominate while at high Reynold’s no:’s inertia forces dominate  Reynold’s no:=ρυc/µ  Low reynold’s no: flights may have lift to drag ratioof 5 to 10(conventional flights have these ratios 3 to 4 times higher)
  7. 7.  Due to small size it needs to have high surface to volume ratios to generate the required thrust  Aspect ratio=WS/chord length ,or WS²/total wing area  Exact ratio depends upon the total weight  The best aspect ratios usually lie between 1&2  Stability and control issues related to low weight ,small moment of inertia ,wind gusts also needs to be addressed
  8. 8.                                                                                                                                                        
  9. 9.  Angle of attack shoud be 5-12° for good endurance.  If angle of attack <5, low aerodynamic efficiency  Endurance=φ/powerequirement  For optimal endurance the mav shoud fly at7°  Hysterisis may occur (lift to drag ratio different from normalwhen angle of attack differs)
  10. 10.  Use strategies using MEMS to improve aero dynamic perfomance  Create &install tiny sensors to dynamically adjust camber(curvature)and shape depending on instantaneous conditions  miniature actuators can be used to move the control surfaces like rudders ailerons and flaps  Flow character over the wings could be controlled by sensor arrays that detect shear stresses or fluid vortices  Flexible mebranes or micro flaps to affect the flow as required
  11. 11.  Flow seperation an be mitigated by air sution or absorption as required,(requires micro valve or pump),wallheat transfer or electro magnetic force as required  Exhausted air is directed out of the trailing edge to prevent flow seperation,which also inreases lift  Micro motors piezoelectricdevices magneto elastic ribbons are all alternatives for performing the actuator function in a flight control system  Processing these control systems may require soft computational techniques like fuzzy logic,neutral networks,genetical algorithms or knowledge based systems
  12. 12.  Rotary wings, fixed wings, or alternate flapping& gliding wings could be employed  Wing shape could be circular, elliptical, rectangular, Zimmerman or inverse Zimmerman  Flapping &gliding and inverse Zimmerman proved to be most efficient  Wing type depends on requirement  Composite materials ,carbon fibre cloth strips, carbon fibre-balsawood sand witches are commonly used  Single or double layer of carbon fibre cloth wetted with epoxy resin  Balsa wood for frame and carbon fibre glass cloth for reinforcing critical areas like leading edges and wing tips is a super combination
  13. 13.  Distend (fill) with air or gas  Application in UAV, military  To stow the wings  Can be launched from gun or aircraft
  14. 14.  Can be packed to 1/10 of original size  Low mass  Low power requirements  High reusability  It can be steered, accelerated, and decelerated in level flight.  High stability and control  High lift and slow landing speed
  15. 15.  Experiment conducted using I 2000  It was launched from 800-1000 feet  Inflatable wings comes out in 13 sec  Successfully controlled the launch,flight and landing
  16. 16.  by using piezoelectricby using piezoelectric materialmaterial
  17. 17.  actuator can be quartz and substrate can be aluminum or steel  inflatable wings has smooth surface so low value of skin friction
  18. 18.  Propulsion system alone consumes 90% of total power  Lithium alkaline batteries  IC engines  Pulse jet engines  Micro jets  Reciprocating chemical muscle  Self consuming system  Lithium battery that recharges using solar energy and fuel cells are also future prospects
  19. 19.  A video/still camera, various sensors ,a micro processor, transducers& an omni directional antennae are the major components  Challenges are small antennae, restriction of power available  Based on the application either cellular communication or satellite communication could be employed.  CCD cameras and IR sensors, nuclear, biological or chemical agent sensors, acoustic sensors could be used.
  20. 20.  Completely autonomous navigation system needs to have the ability to use sensory data for on board processing thus avoiding obstacles. (complete dependence on remote is undesirable)  A combination of GPS+inertial sensing is ideal  Geographical information system to provide a map terrain for infrastructure would be great  Pressure sensors acting as altimeters, accelerometers, low drift gyroscopes and also systems capable of locating the mav ’s position with respect to the launch point form a part of the inertial navigation system
  21. 21.  Micro Air Vehicles are a class of UAVs whose time has just about come. A confluence of key events is about to occur that will enable these versatile aircraft to have military effects disproportionate to their diminutive size. The supporting technologies are progressing rapidly to the point that first simple, short-duration missions will be possible, then with time, more varied and enduring applications. At the same time, the need for weapons that help achieve the Joint Chief of Staff vision for dominant maneuvering precision engagement, full dimensional protection, and focused logistics will be more pressing than ever. The military utility of MAVs in this context can only grow as they come closer to realizing their potential. At the start, microairvehicles could find application by providing localized imaging reconnaissance. Then as other key technologies mature, uses may expand to electronic warfare, nuclear, biological, and chemical agent warning, and battle damage assessment. Later still, we could see MAVs autonomously flying through air shafts reconnoitering deeply buried bunkers and reporting back to enable proper configuration of penetrating weapons. MAVs might then proliferate throughout the force structure becoming as much an — arrow in the quiver“ of the foot soldier as another round on the hardpoint of a fighter‘s wing.
  22. 22.  Research paper “Death by a thousand cuts”micro air vehicles in the service of air force missions- by ARTHUR F HUBER,II LT COL USAF  http://mil.ufl.edu/~nechyba  2. Davis, W.R., "Micro UAV," Presentation to 23rd Annual AUVSI Symposium, 15-19 July, 1996.  Research paper by James M. McMichael Program Manager Defense Advanced Research Projects Agency  and  Col. Michael S. Francis, USAF (Ret.) formerly of Defense Airborne Reconnaissance Office  MICRO AERIAL VEHICLE DEVELOPMENT: DESIGN, COMPONENTS, FABRICATION, AND FLIGHT-TESTING Research paper by Gabriel Torres and Thomas J. Mueller  117 Hessert Center, University of Notre Dame  Notre Dame, IN 46556  DESIGN AND DEVELOPMENT OF A MICRO AIR VEHICLE  CONCEPT: PROJECT BIDULE  Mr T. Spoerry1, Dr K.C. Wong  School of Aerospace, Mechanical and Mechatronic Engineering  University of Sydney  NSW 2006
  23. 23.  Aerodynamics for engineers:-John J. Bertin  Mechanics of flight :-A.C Kermode  Inflatable wing on aircraft article :-new scientist june 2001  www. nasa explores. COMaerodynamicsinflatable wing  Miller, Jay,, The X-Planes, Aero fax, Arlington, Texas, 1988  morphing of inflatable wing for UAV David Cardigan* and Tim Smith†  ILC Dover, Frederica, DE 19946  Innovative Wing Design Could Soar in Martian Skies by benianntova  Inflatable wing for high lift john H gleen research centre Ohio  www.nastech.com/mechtech  www.spaceref.com/newtech  www.nasa.gov/aerodynamics  www.nasa.gov/multimeadia
  24. 24.  Mueller, T. J., "Low Reynolds Number Vehicles", AGARDograph No. 288, 1985  Lissaman, P. B. S., "Low-Reynolds-Number Airfoils", Annual Review of Fluid Mechanics, Vol. 15, 1983, pp. 223-239  Burgart, M., Miller, J., and Murphy, L., "Design of a Micro Air Vehicle for the 2000 MAV Competition", internal progress report, University of Notre Dame, 2000  ernet, 14 December 2000, available from http://defence-data.com/f2000/  pagefa1006.htm.  Air Force 2—A New Thrust in DERA Micro Air Vehicle Development,“ 24 July 2000, n.p.: On-line.  Int 025, August 1996, n.p.; On-line. Internet, 18 December 2000, available from  http://www.au.af.mil/au/2025/index2.htm.  Air Force Doctrine Document (AFDD) 1, Air Force Basic Doctrine, September 1997.  Air Force Scientific Advisory Board, New World Vistas Air and Space Power for the 21st  Century Summary Volume, 1995, n.p.; On-line. Internet, 4 December 2000, available  from http://www.sab.hq.af.mil/Archives/1995/NWV/vistas.htm.  Ashley, Steven, —Palm-size Spy Plane,“ Mechanical Engineering, February 1998, n.p.;  On-line. Internet, 16 November 2000, available at http://www.memagazine.org/  backissues/february98/features/palmsize/palmsize.html.  Ashley, Steven, —Turbines on a Dime,“ Mechanical Engineering, October 1997, n.p.; On-  line. Internet, 16 November 2000, available at http://www.memagazine.org/  backissues/october97/features/turbdime/ turbdime.html.  Barrows, Geoffrey L., —Optic Flow Sensors for MAV Navigation,“ Proceedings of the  Conference on Fixed, Flapping and Rotary Vehicles at Very Low Reynolds Numbers,  5-7 June 2000, University of Notre Dame, ed. Thomas J. Mueller, 13 pages.  Brendley, Keith W. and Randall Steeb, Military Applications of Microelectromechanical  Systems, RAND Report MR-175-OSD/AF/A. Santa Monica, CA: RAND, 1993.  Carroll, Bruce, —MEMS for Micro Air Vehicles,“ Project Summaries, n.p.; On-line.  Internet, 24 August 2000, available from http://www.darpa.mil/MTO/MEMS/  Projects/individual_66.html.  Carroll, S., —US Navy, DARPA Develop IMINT/EW Payloads for Mini-UAVs,“ Journal  of Electronic Defense 21, no. 9 (September 1998): 30-32.  Chandler, Jerome Greer, —Micro Planes,“ Popular Science 252, no. 1 (January 1998): 54-  59.

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