Micro Air Vehicle Design-1vw11map01

MICRO AIR VEHICLE (MAV) DESIGN

Presented by

Deepak Raj P.Y

USN No: 1VW11MAP01

04/21/2023 VTU-Center for PG Studies, Bengaluru Region.

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MICRO AIR VEHICLE DESIGNContents….!! What is MAV? Main sub systems. Flight control & aerodynamics. Propulsion system System integration MAV design based on animal

flight. Biological inspiration to a

flapping vehicle.

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MICRO AIR VEHICLE DESIGN

What is a MAV?Multi functional, militarily

capable, small flight vehicles.

Size should be less than15cms.

To fly at Reynolds numbers of less than 10⁴.

Will weigh less than 90g.

VTU-Center for PG Studies, Bengaluru Region.


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MICRO AIR VEHICLE DESIGNWhy MAV’s? Why not something bigger?• Growing realization by military planners. • Real-time information and intelligence on

enemy strength, dispositions and tactics essential for battlefield success.

• MAVs represent a potentially inexpensive and expendable platform for surveillance and data collection in situations where larger vehicles are not practical.

• Direct connectivity• Can be individually controlled

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Applications….. Reconnaissance Surveillance Defence applications Weather forecast Wildlife study

&photography Crowd control

Targeting Border surveillance Traffic monitoring Tracking criminals &

illegal activities Biochemical sensing inspection of pipes



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MICRO AIR VEHICLE DESIGNDesign Flowchart


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Main sub systems… Flight Control. Propulsion System. Communication System. Guidance & Navigation.


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MICRO AIR VEHICLE DESIGNFlight Control & Aerodynamics• Completely different aerodynamics due to low

Reynold’s number.• Reynold’s no = inertia force/viscous force.• Flights may have lift to drag ratio of 5 to

10(conventional flights have these ratios 3 to 4 times higher).

• Due to small size it needs to have high surface to volume ratios to generate the required thrust.

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MICRO AIR VEHICLE DESIGN• Aspect ratio=WS/chord length ,or WS²/total wing

area. • 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.



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MICRO AIR VEHICLE DESIGNActive & Passive Control• Use strategies using MEMS to

improve aero dynamic performance.

• 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.

Piezo-electric material

Magnetic Actuator


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MICRO AIR VEHICLE DESIGN• Flow character over the wings could be

controlled by sensor arrays that detect shear stresses or fluid vortices.

• Flexible membranes or micro flaps to affect the flow as required.

• Exhausted air is directed out of the trailing edge to prevent flow seperation, which also increases lift.

• Micro motors piezoelectric devices 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 algorithms or knowledge based systems.

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MICRO AIR VEHICLE DESIGNWing Design & Fabrication• Rotary wings, fixed wings, or alternate flapping&

gliding wings could be employed


Examples of MAVs. (a) Flexible fixed wing; (b) Rotary wing; (c) Hybrid flapping-fixed wing, using fixed wing for thrust generation; and (d) Flapping wing.


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MICRO AIR VEHICLE DESIGN• 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.


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MICRO AIR VEHICLE DESIGNPropulsion System• Propulsion system alone consumes 90% of total

power.• Lithium alkaline batteries.• IC engines.• Pulse jet engines.

• Micro jets.

• Lithium battery that recharges using solar. energy and fuel cells are also future prospects.


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MICRO AIR VEHICLE DESIGNCommunication System• 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.


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MICRO AIR VEHICLE DESIGNGuidance & Navigation• 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


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MICRO AIR VEHICLE DESIGNSystem Integration


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MICRO AIR VEHICLE DESIGN MAV design based on Animal Flight

Aerodynamics of animal flight. Forces at each instant are modeled by the

assumption of inherently time – independent fluid dynamic mechanisms, then such a model is called ‘ quasi – steady’.

The fluid flow around an insect wing is described by the incompressible Navier – stokes equation, given by

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MICRO AIR VEHICLE DESIGNAerodynamics of animal flight. Measuring pressure field is difficult in the space

around the wing, therefore pressure term can be eliminated, resulting in the equation.

Vorticity: if ŵ = 0 irrotational flow -> Potential theory

To calculate aerodynamic forces, small vorticity elements are integrated over the surface area around an airfoil

The quantity on the left hand side is circulation



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MICRO AIR VEHICLE DESIGNAerodynamics of animal flight Kutta condition and Circulation

Physical modeling of animal flight Dynamic scaling should be done. Results in several unsteady mechanisms– Wagner Effect– Clap and Fling– Delayed stall– Rotational lift– Wing – wake interactions


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MICRO AIR VEHICLE DESIGNAerodynamics of animal flightWAGNER EFFECT• When an inclined wing starts

impulsively from rest, the circulation around it does not immediately attain its steady – state value. Instead it raises slowly.

• This delay is a result of combination of two phenomena.

– Inherent latency in the viscous action on the stagnation point and thus a finite time before the establishment of Kutta condition

– Vorticity is generated and shed at the trailing edge


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MICRO AIR VEHICLE DESIGN Aerodynamics of animal flight

CLAP AND FLING• Explains high lift generation • Combination of two separate

aerodynamics mechanisms, treated independently– Clap – Wings touch the

dorsally before they pronate to start the down stroke the leading edges of the wings touch each other before the trailing edges.

– Fling – Wings pronate by leaving the trailing edges stationary as the leading edges fling apart


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MICRO AIR VEHICLE DESIGN Aerodynamics of animal

flightDELAYED STALL• Separation of fluid flow over the

wing as the angle of attack increases

• The flow reattaches before it reaches the trailing edge.

• The wing translates at a higher angle of attack, a greater downward moment is imparted to the fluid substantial enhancement of lift.

• Polhamus accounted for enhancement of lift Leading edge suction at low angles of attack

POLHAMUS LEADING EDGE SUCTION TECHNOLOGY


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MICRO AIR VEHICLE DESIGNBiological inspiration to a Flapping wing vehicle


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• Structural concept for flexible wings• The MAV design, though it employs a fixed wing and

propeller arrangement, it also incorporates a very light flexible wing structure that is to provide improved stall margins and flying qualities.

• The wing layouts were developed from the photographs of humming birds with their wings extended that were scaled to have a wing length of 75mm.


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A humming bird in hovering flight illustrates the reversible camber exhibited by its flexible wing structure


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How did we get the MAV weight?


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MICRO AIR VEHICLE DESIGNMAV flight regime compared with existing flight

vehicles


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Current MAV Problems• Short flight times

– Low battery life

• Control Issues– Unpredictable forces and

moments – Wind gusting

• Limited space– Controls

– Power source


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MICRO AIR VEHICLE DESIGNConclusion• This work studies an emerging body of multidisciplinary

knowledge in the area of biologically inspired micro-scale flight.

• Understanding force generation on a flapping wing, though a difficult feat, is only a beginning of our understanding of flapping flight in nature as a whole.

• The study of unsteady aerodynamics of a biological flight is performed and various theories explaining unsteady mechanisms are discussed.

• The research activity, still in its infancy seeks to gain and apply an understanding of natural fliers in the size range of the micro air vehicle class


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MICRO AIR VEHICLE DESIGNReferences• Z. Jane Wang , “Dissecting Insect Flight” - Annual. Rev. Fluid Mech. 2005.

37:183–210• Gordon J. Berman And Z. Jane Wang , “Energy-Minimizing Kinematics In

Hovering Insect Flight” - J. Fluid Mech. (2007), vol. 582, 153–168.• Sanjay P. Sane, “The Aerodynamics of Insect Flight” - The Journal of

Experimental Biology 206, 4191-4208.• 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://defencedata.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.

http://defencedata.com/f2000/




http://defence-data.com/f2000/pagefa1006.htm



http://www.au.af.mil/au/2025/index2.htm

http://www.au.af.mil/au/2025/index2.htm


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THANK YOU

Micro Air Vehicle Design-1vw11map01

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