BUILD A QUADROTOR

RC Hovercraft .

2011-09-10T19:39:00.003+05:30

We have made a hovercraft for for Shaastra (Technical festival of IIT Madras) . Here are some pics and Video of our hovercraft.One brushless motor is used for thrust required to lift the hovercraft ,second motor is used to propel the machine .Servo is used for turning the hovercraft by thrust vectoring of the propelling motor .

Items used:
1)2X 2200Kv Brushless motors/25ams controller
2)6ch Radio
3)Standard servo
Thermocol (30cmX30cmX5 cm),glue

1st prize(navygator TATHVA) winning RC Boat.... build

2010-10-23T17:20:00.002+05:30

we made a RC Boat for TATHVA( http://bit.ly/aIWjaK ) and won 1st prize.here i am posting some pics and videos of boat.

Description of components:
1)Brushless outrunner CF2812(maximum power @80 % efficiency 120w )
2)ESC 18A (inbuilt BEC)
3)6ch tx& rx(72mhz)
4)aquaprop ,propeller
5)Servo motor ,rudder
6)some plywood thermocol and a LOT of super glue ;)

our runtime was 10 seconds......with no obstacles hit....

work continues on making the controller ... components arrived

2010-09-12T20:26:00.000+05:30

we will be using atmel micro controller for processing data from receiver and gyro ....

more updates to come....

Got my gyros(as a project contribution from SUJJU sir)

2010-04-19T15:44:00.000+05:30

first we will try mixing approach then we can remove the sensors and try the uC approach..

solar powered vehicle (update)

2010-04-14T16:54:00.000+05:30

some more videos and pics...

i will be getting my gyros tomorrow and then only i can continue working on my quad ...videos and pics of quad to be updated soon....
enjoy

http://www.youtube.com/watch?v=2p7lX0Ibpyg

DIY Solar Powered Vehicle

2010-03-30T18:42:00.001+05:30

Meanwhile we have made a solar powered vehicle for our college project, based on IC555 as time trigger,

Solar cars may be propelled using a pulley/ rubber band method or some types of interlocking gears.
WHAT DO WE NEED
Solar Cell 16V ,5W
DC motor 12V,75 rpm
Front Wheels 7cm diameter
direct drive
Wood Sheet
Motor Mount (With straps if needed)
saw
super glue
rear wheels
THE SOLAR ENGINE(IC555,16v 4700uf capcitor,IN4148,NPN transistor Ic=2amps,68k R)

SELECTING THE GYRO

2010-03-03T16:30:00.000+05:30

the basic controls are
1)throttle
2)rudder
3)elevator
4)aileron

so we need atleast 4 channels to control.for gyro selection ,any gyro will do having sensitivity more than 50deg/s and gain we can adjust later according to our configuration.
working of gyro:when gyro is not getting any signal(to varry speed)from rx it will uppose the movement (on a paticular axis) by providing +ve or -ve signal to ESC and thus controlling the motor.
But when a signal comes from the rx it let pass that signal to esc.so we can varry the speeds manually

For microcotroller approach,i m going to post later, we need only sensor of gyro ,ie. VCC,GND,OUT pins are needed.
there must be atleast three gyros,one for each axis (X,Y,Z).
piezo gyros are very commonly available and cheap gyros,if you want the heading hold feature you should buy a HH(heading hold) gyro.

selection of MOTOR,PROP and ESC

2010-02-16T07:47:00.000+05:30

selection of motor entirely depends on the weight of the quadrotor,
here i have given some commonly available motors with respective weight of quadrotor,
one should always take a margin so that he can add extra features later (like real time videography or fpv),
thrust can be multiplied by 4 to give the total thrust so here i am giving thrust of one motor at normal running conditions and recommended propeller.
model voltage current thrust esc prop model wt.
cf2812 11.1v 11 a 460g 18a 8*4.8 1kg
cf2812 7.4v 10a 320g 18a 7*5 800g
cf2822 11.1v 12.3a 720g 18a 8*4.8 1.5kg
cf2822 7.4v 9.3a 430g 18a 7*5 1kg

slow flyer props are preffered in quadrotor.

HOW MIXERS WORK

2010-02-13T06:30:00.000+05:30

I am sure you are familiar with radios and receivers and such, so i will move to the v-tail mixers.
A v-tail mixer(or simply mixer) takes two signals, one through a master input and one through a slave input.
There are two wires that come out. One of them will be the master input + the slave input, and one will be the master input - the slave input.
So if you had a master of (a random number) 6, and you had a slave of 3, one output would be 9 and one would be 3. When you average the two values you get 6, the master input value. This is the case for any set of values that comes through.
So if you hooked the master up to a throttle channel , and the slave to an aileron channel and place the motors you are controlling with them on opposite ends of the model. When you increased the throttle, both motors would speed up. When you slave input, one motor will speed up and the other one will slow down. This will cause your model to tilt, but your average throttle will remain same.

If you wanted to control both aileron and elevator, you have to split up the throttle chanel, one going to the master of each veetail and elevator to the spare slave channel on your new mixer, and you have control of both aileron and elevator.
for a quality control system mixer resolution must be in the range of 200-500 steps per second.

the mixing approach

2010-01-31T05:27:00.001+05:30

i have got an idea on rcindia of making it using V-Tail mixer (mixer is a device which mixes 2 input signals to give 2 output signals) the diagram of mixing is given .

got my components

2010-01-11T01:36:00.000+05:30

i have got the components used in mixer approach

1)FUTABA R136F 72mhz full range reciever
(1kilometer range)

2)FUTABA T4YF 72mhz 4 channel
transmitter (channel 3 needs to be reversed)

3)ESC (electronic speed controller) 18amps
, to run brushless motor.

4)CF 2812 BLDC motor
12 pole,11.1v,7.4v
SPECIFICATIONS OF MOTOR

Model Cells KV Prop RPM Current Thrust

CF2812 3S 1534 7X6 11000 15.5A 730g

CONTROL SYSTEM OF QUADROTOR

2009-05-01T05:59:00.000+05:30

For control system you will need to interface brushless controllers(ESC). so find some mixer that support such a high update rate (>200 steps/s). and see how it works.

also, find i way to interface with a rc-receiver,and the gyros, gyro sensitivity can vary from as low as 50 degrees/s to as high as 450 degrees/s we dont actually need very high sensitivity ,so no need to throw your money
once you have all that running, build a frame and buy the rest of the esc and motors. the actual stabilisation is (relatively) very easy.

i will be posting the interfacing diagram later

Planning to get Brushless motor

2009-02-23T03:12:00.000+05:30

we are planning to get brushless motor to continue the project as brushed motors dont have required thrust,i.e. power to weight ratio is less ,
for any flying object power to weight raio must be in the range of 1.1 to 1.8
we are planning to get Emax cf2812 brushless motor.

brushed motors are useless

2008-12-13T04:13:00.000+05:30

have tried every possible way to take all the juice brushed motors have got but was unable to lift my quadrotor,just because weight to thrust ratio is high

quadcopter build

2008-10-01T04:44:00.000+05:30

work started to build a quadcopter using brushed dc motors and DIY props.

looks like the brushed dc motor is not having enough torque
to give the required thrust.
the weight of model is 250 grams ,and is decreased to 147 drams after full speed of motors.