micro air vehicles. what are mavs( av’s)? multi functional, militarily capable, small flight...
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MICRO AIR VEHICLES
WHAT ARE MAVS(AV’S)? Multi functional, militarily capable, small flight
vehicles. size should be less than15cms. Reynolds's no < 10^5. For a Primarily intended and developed for
defence applications.
WHY MAV’S? WHY NOT SOMETHING BIGGER?
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-of before)
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
OVER THE HILL RECONNAISSANCE
MOTHER BIRD APPROACH
Tracking of chemicals
MAIN SUB SYSTEMS
1. FLIGHT CONTROL
2. PROPULSION SYSTEM
3. COMMUNICATION SYSTEM
4. GUIDANCE&NAVIGATION
MAV flight regime compared with existing flight vehicles
FLIGHT CONTROL&AERODYNAMICS
Reynolds's no:= inertia force/viscous force Low Reynolds's no: flights may have lift to drag ratio of 5
to 10. The best aspect ratios usually lie between 1&2 Angle of attack should be 5-12° for good endurance. If angle of attack <5, low aerodynamic efficiency Endurance=/power requirement For optimal endurance the mav should fly at7°
ACTIVE OR PASSIVE CONTROL
Use strategies using MEMS Create &install tiny sensors miniature actuators Flow character controlled by sensor arrays Flexible membranes or micro flaps to affect
the flow as required Micro motors piezoelectric devices magneto
elastic ribbons
WING DESIGN AND FABRICATION
Types of wings
wing shapes
Composite materials,
Carbon fibres
carbon fibre-balsawood sand witches are commonly used
Inflatable wing
Distend (fill) with air or gas
Application in UAV, military
To stow the wings
Can be launched from gun or aircraft
Advantages of aircrafts with inflatable wings
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
Experiment on inflatable wing
Experiment conducted using I 2000
It was launched from 800-1000 feet
Inflatable wings comes out in 1\3 sec
Successfully controlled the launch,flight and landing
Controlling of wing
by using piezoelectric by using piezoelectric materialmaterial
actuator can be quartz and substrate can be aluminum or steel
inflatable wings has smooth surface so low value of skin friction
I-2000 & X-24A
Both have inflatable wing
I-2000 is UAV X-24A is manned
Disadvantages
They are not self powered
Cannot launch from ground
There are chances of air bag buckling
PROPULSION SYSTEM
Propulsion system alone consumes 90% of total power
Lithium alkaline batteries IC engines Reciprocating chemical muscle Lithium battery that recharges using solar
energy and fuel cells are also future prospects Self consuming systems
COMMUNICATION SYSTEM
A video/still camera, various sensors, micro processors, Transducers & an omni directional antennae
GUIDANCE AND NAVIGATION
A combination of GPS+inertial sensing is ideal
Geographical information system to provide a map terrain for infrastructure would be great
Pressure sensors
MAV SYSTEM INTEGRATION