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CONTENTS
INTRODUCTION.
FUNCTIONS.
TYPES AND WORKING.
ABOUT THE FLAPPING WINGS USING WEIS FOGH’S MODEL.
MECHANISM AND ITS FEATURES.
CONCLUSION.


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)


COMPARISON WITH OTHER AIR VEHICLES
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
FUNCTIONS
Reconnaissance applications.
FUNCTIONS
Operation in constraint environment.
FUNCTIONS
Bio chemical sensing.
TYPES
Which uses propellers.
Similar to that of normal aircrafts or
Which uses flapping wings.

CHARACTERISTICS OF THE FLAPPING WINGS
Lift is generated by the airflow created by the vehicle speed.

And also the wing flapping will support the weight of the vehicle.

Can be operated at very less vehicle speed.

WEIS FOGH’S 2D MODEL
IMPORTANCE OF THIS MODEL
Compared to ordinary flapping this model will be generating more lift, (Circulation).
Opening of the wings by rotational movement.
Separation of the wings by translation movement.
Flapping of the wings.
MECHANISM
MECHANISM
DESIGN PROCEDURE
To design the mechanism the three positions of the wings are utilized.

First of all, the flapping movement of the wings is designed assuming the positions of the fixed pivots, O1 and O2.

The position of points A and B are determined.

The criterion for a feasible solution is that the links should be in the range of 1cm 4cm.

The steps are repeated until all the conditions are satisfied.

Next the driving mechanism O3CAO2 is designed.

Trying many times, the movements of the wings are obtained as required, in specified dimension limits.
ANALYSIS
The dynamic and the resultant loads were analyzed assuming the linkages to be made of steel. (Width 5mm and thickness 1mm)

The maximum acceleration occurred at position of about 1200 of page link O1B.

Assuming the page link O2A is moving with average angular velocity of 100 Hz and zero angular acceleration.
ANALYSIS
The driving mechanism O3CAO2 has not included in this analysis.

This analysis is used to compute the forces on the pin joints and the links.

From the analysis, the maximum force is on joint O2 and is of magnitude 31.38 N.

When the mechanism is oscillating, there are unbalance forces acting on it.
ANALYSIS
In a flying mechanism the imbalances are damped due to viscous interactions in the low Reynolds number regime.

All horizontal forces will be cancelled by oppositely working mechanisms for the two wings.
ESTIMATED LIFT
The lift generated by the above mechanism is evaluated in terms of lift coefficient (CL).

CL = (1.38 ** c)/U where,

 is the angular velocity of the wings.

c is the chord length and U is the forward velocity.

The angular speed  = 60 rpm.

Chord length c = 15 cm.

This will give a lift coefficient of 1.38 when the forward speed of the vehicle is 1 m/s.

This is comparable with the lift coefficient of well-designed airfoil at an angle of attack of about 6-8o.
CONCLUSION
Micro Air Vehicles are new development of the technology by which a variety of operations are done.

Simple flapping of the wings does not generate sufficient lift.

So special mechanism is designed to get the required lift using Weis Fogh’s model.
FUTURE WORK
The future attempts will be for designing the mechanism for a forward movement.
And reducing the weight of the vehicle using lighter material.
Then to achieve high flight speeds, better stability in air.
And also to maximize the battery life.

REFERENCE
S. MUKHERJEE, S. SANGHI; “Design of a Six-Link Mechanism for a Micro Air Vehicle”, Defense Science Journal, Vol. 54, No. 3; July 2004.
JAMES M. MC-MICHAEL, COL. MICHAEL S. FRANCIS; “Micro Air Vehicles: Toward a New Dimension in Flight; darpa.mil
ON Aerodynamic modelling of an insect-like flapping wing in hover for micro vehicles.
Rafal Zbikowski
doi: 10.1098/rsta.2001.0930
Phil. Trans. R. Soc. Lond. A 2002 360, 273-290

DESIGN AND DEVELOPMENT OF A MICRO AIR VEHICLE (μAV)
CONCEPT: PROJECT BIDULE
Mr T. Spoerry1, Dr K.C. Wong
School of Aerospace, Mechanical and Mechatronic Engineering
University of Sydney
NSW 2006