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Author Topic: Need to build a quadrocopter  (Read 15166 times)

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Offline praveen_khmTopic starter

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Need to build a quadrocopter
« on: January 28, 2010, 03:55:25 PM »
Hello friends.

Am planning to build a QuadroCopter. Till now, I have built the 50$ robot successfully and then stopped. Now, I am back to robotics after a year long gap.

But not sure what all do i need to use for the QC. To start with, i have the following:
1. Use Atmega8 for programming
2. 4 brushless motors
3. Wood or Carbon fibre body
4. H-bridge for motor control with PWM
5. 12v battery.
6. Tx and Rx for controlling.

I have only this. Do I need anything else? I have heard of gyro, accelerometer or all. but is it really required to just make the thing fly.. and just fly?

All and any your suggestions are welcome. This is a fair idea.
I have no ideal on what to build. If you can guide me to a good site or tutorial, it would be helpful.

Thanks,
Praveen
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Offline Razor Concepts

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Re: Need to build a quadrocopter
« Reply #1 on: January 28, 2010, 04:10:40 PM »
The very first step you need is to learn how to fly RC helicopters. You cannot just program a quadrocopter, press a button and it will work perfectly. Before one is autonomous, it has to be teleoperated to verify everything.

Gyros/accelerometers are absolutely necessary!!!! It's like trying to drive a car with a blindfold on!

Brushless motors cannot be driven from the h-bridge easily. Just buy an Electronic Speed Control. Making the motors work with the h-bridge is a huge task in itself.

Offline SmAsH

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Re: Need to build a quadrocopter
« Reply #2 on: January 28, 2010, 06:48:55 PM »
You WILL need a gryo/accelerometer to tell your quadrocopter what angle it is at.
Without one your copter would flip our straight after takeoff.
Howdy

Offline praveen_khmTopic starter

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Re: Need to build a quadrocopter
« Reply #3 on: January 29, 2010, 09:38:30 AM »
oh wow!! What a start  :-[

So, I definitely need a gyro/acc. Does anyone of you are aware of any good tutorials which can guide me on that?
I have made up my mind to do it. Sadly, if it fails, i need to keep trying. But if already tested and done, that would reduce the failure chances. Also, I tested the H-bridge with DC motors, they are working well. So, would that suffice to start with?

Can someone guide me?

Thanks for all the responses.
Robot building is all about sharing and learning
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www.robotplatform.com : Beginners guide to Electronics & Robotics

Offline Razor Concepts

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Re: Need to build a quadrocopter
« Reply #4 on: January 30, 2010, 08:10:12 PM »
Search for mikroquad, aeroquad, etc etc. There is a significant amount of information out there that will keep you occupied for quite a while  ;)

There really is no step-by-step guide on quadrocopters because they are just too complicated to have a single solution.

Additionally, the vast majority of quadrocopter information are on RC forums, like rcgroups.com. Hint hint, you will need to learn how to fly before making your own quad  ;)

Offline Hertz32

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Re: Need to build a quadrocopter
« Reply #5 on: February 01, 2010, 12:42:05 PM »
 i agree u will need to learn i bought a couple of those mini helis ::) then spent 30 on a 40cm 1 before i thought i was good enough .

Offline praveen_khmTopic starter

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Re: Need to build a quadrocopter
« Reply #6 on: February 03, 2010, 12:15:18 AM »
Thanks guys... have started looking for othe materials. Will post if I can succeed in any.
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Offline hemanth

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Re: Need to build a quadrocopter
« Reply #7 on: March 27, 2010, 08:03:16 AM »

Offline Comrade117

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Re: Need to build a quadrocopter
« Reply #8 on: April 07, 2010, 01:06:57 PM »
Is it possible to build helicopter like this?



Well, important are only rotors now, not body...

If upper and downer rotors are rotating in opposite direction, and of course, blades are much longer, will this machine be able to fly?
There is simple way to use only 2 motors for rotors, but I am not sure if it is good for balancing. There would be another 2 motors setting "wings" angle, to control speed and steer around.

So controls would be:

angle: + (speed up)
angle: - (slow down, fly back)

left angle: +, right angle: - (turn right)
right angle: +, left angle - (turn left)
left rotor: + speed (dive right)
right rotor: + speed (dive left)

rotor speed: - (decrease height)
rotor speed: + (increase height)

There is problem:
increasing angle will speed up machine, but lower altitude, so I would have to increase rotation speed.
And I need very light material, but hard enough to survive my bad driving :)
Oh, remote control can do all this? Well if I build this machine, I would have to carefully increase or decrease motor speed each time I want to steer, and I would probably brake it down after first 15 minutes lol


« Last Edit: April 07, 2010, 01:10:23 PM by Comrade117 »

Offline amando96

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Re: Need to build a quadrocopter
« Reply #9 on: April 11, 2010, 12:33:10 PM »
Hmm, i'm not sure if normal DC will work, most people use brushless motors and lipo batteries, much more powerfull and lighter..
this guys is making one:
http://lusorobotica.com/index.php?topic=1660.0

it's in portuguese, google will give you an acceptable translation though.
Rorcle, 60% complete
AATV, 5% complete

Offline Razor Concepts

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Re: Need to build a quadrocopter
« Reply #10 on: April 11, 2010, 03:26:53 PM »
The thing that won't work on something like that is the pitch angle. Just moving the rotors forward and backward won't angle the helicopter, as there is nothing keeping anything in balance.

Offline corrado33

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Re: Need to build a quadrocopter
« Reply #11 on: April 12, 2010, 04:54:31 PM »
Quote
There would be another 2 motors setting "wings" angle, to control speed and steer around.
  You'd probably be better off using servos instead of motors for a couple reasons.  1.) The wing's angle doesn't turn more than 90-180 degrees.  2.) Servos have built in position control.  For a motor you'd have to use an encoder or an expensive (stepper?) motor to know what angle's the wings are actually at.  With a servo you simply tell it to turn to a certain angle, and it goes there and stays there.  (Unless you hit something...)

Quote
And I need very light material, but hard enough to survive my bad driving

I'd say foam at first, you know the stuff that those mini RC copters are made of.  (The foam that when you break apart it turns into a million little balls of foam?)  It's hard enough, takes a lot of abuse, and is very light. And if you break it you can always make another body. 

Offline Comrade117

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Re: Need to build a quadrocopter
« Reply #12 on: April 14, 2010, 11:03:01 AM »
The thing that won't work on something like that is the pitch angle. Just moving the rotors forward and backward won't angle the helicopter, as there is nothing keeping anything in balance.
Yes, you are right.  :-\
So what now? Heavier hull?

Quote
There would be another 2 motors setting "wings" angle, to control speed and steer around.
  You'd probably be better off using servos instead of motors for a couple reasons.  1.) The wing's angle doesn't turn more than 90-180 degrees.  2.) Servos have built in position control.  For a motor you'd have to use an encoder or an expensive (stepper?) motor to know what angle's the wings are actually at.  With a servo you simply tell it to turn to a certain angle, and it goes there and stays there.  (Unless you hit something...)

lol
I never knew the difference between servos and motors... Now I know ;D
Let me guess: servos are much more expansive, but better.



Offline coptersky

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Re: Need to build a quadrocopter
« Reply #13 on: July 15, 2011, 03:02:30 PM »
You can find good quadrocopter or hexa frames http://www.coptersky.com/

 


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