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Quadrotor

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					                  SUMMER PROJECT(QUADROTOR)

INTRODUCTION


A Quadrotor is basically a multicopter which has four arms and a motor mounted
on each arm in to lift or propel it. It is also referred to as an UAV(Unmanned Air
Vehicle). We got the idea of taking up this project because the project had a lot of
scope and it was quite fascinating to build a multirotor.The project was a inter
club project with the electronics club.




MECHANISM


Each rotor produces both a thrust and torque about its center of rotation, as well
as a drag force opposite to the vehicle's direction of flight. If all rotors are
spinning at the same angular velocity, with one pair on the same arm rotating
clockwise and the other pair on the other arm rotating counterclockwise, the net
aerodynamic torque, and hence the angular acceleration about the yaw axis is
exactly zero, which implies that the yaw axis motion is stabilized . Yaw is induced
by mismatching the balance in aerodynamic torques (i.e., by offsetting the
cumulative thrust commands between the counter-rotating blade pairs).

Angular accelerations about the pitch and roll axes can be caused separately
without impacting the yaw axis. Each pair of blades rotating in the same direction
controls one axis, either roll or pitch, and increasing thrust for one rotor while
decreasing thrust for the other will maintain the torque balance needed for yaw
stability and induce a net torque about the roll or pitch axes. This way, fixed rotor
blades can be made to maneuver the quad rotor vehicle in all dimensions.
In order to control the Quadrotor we have used the ARDUINO Mega Board .Along
the ARDUINO board we have used an 9 DOF(Degree of Freedom) Razor
IMU(Inertial Mass Unit) in order to maintain the balance of the Quadrotor during
its flight.



INNOVATIVE APPLICATIONS


1.A Quadcopter can be used to be capture images by mounting a wireless camera
on it.

2. If a good control is made over the Quadrotor it can be made to shift loads or
perform maneuvers.


RESULTS


We had been given propeller blades of 10x6 (length x Pitch) but during the testing
two of the propellers broke down so we had to use 8 x 6 propellers and we were
just able to lift the Quadrotor from the ground at around 115 RPM.



DIFFICULTIES FACED


1. The choice of material and the motor mount was to be decided. For frame we
had the options of aluminium and balsa , but finally we went with balsa. For the
motor mount we used balsa coated with fibre.

2. Keeping the arms of the Quadrotor must be perpendicular to each other.

3. To maintain the centre of mass of the quadrotor at the meeting point of the
arms before and after mounting the control circuit.
4. The vibrations in the frame must not be induced to the control circuit or else
the IMU that we have used would start giving false readings.

5. The code for the ARDUINO board and IMU were a bit complex and PI settings
take a lot of time to get calliberated.



FUTURE WORK PLAN


We have planned that after we are successfully control the Quadrotor’s flight
with a wireless mechanism we will work on making the quadrotor autonomous by
mounting a wireless camera onto the Quadrotor which would send images which
will monitored on a computer.


REFERENCE AND USEFUL LINKS


http://www.youtube.com/results?search_query=basic+quadcopter+tutorial

http://www.rcgroups.com/forums/showthread.php?t=1284741

http://www.instructables.com/id/RC-Quadrotor-Helicopter/

http://wiki.openpilot.org/display/Doc/Basic+QuadCopter

				
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posted:10/3/2012
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