Thread: Quadrocopter project

  1. #1
    Registered User
    Join Date
    Dec 2006
    Location
    Canada
    Posts
    3,229

    Quadrocopter project

    I decided to start documenting the project I am working on - an autonomous quadrocopter (helicopter with 4 propellers) in the form of a log/tutorial.

    Feel free to stop by if you are into these kind of things!
    http://cyberfish.wecheer.com/quadrocopter

    I haven't really gotten to the programming part, though. Most of it is still electrical/mechanical stuff. But there will be a lot of programming later on.

  2. #2
    Registered User
    Join Date
    Aug 2003
    Posts
    1,218
    Looks like a fun project.
    Last edited by Shakti; 08-05-2010 at 03:30 PM. Reason: i am stupid and cant read

  3. #3
    Registered User
    Join Date
    Dec 2006
    Location
    Canada
    Posts
    3,229
    I was going to use a Cortex-M3 (STM32), but later decided to go with a gumstix (single board computer with a Cortex-A8) because I needed more memory (among other things).

  4. #4
    Registered User
    Join Date
    Aug 2003
    Posts
    1,218
    Yah edited my post, apparently its too late for me to read atm....

    Thought about using a mobile phone to send text-messages with commands to the copter? IE go to gps-coordinate, stay at altitude, take pictures every x seconds and mms them back to the phone and stuff like that? Would be cool so you dont have to rely on the radio or wifi. I realize this is very much in the future but could be a nice addition if you succeed with the radio and wifi.
    Last edited by Shakti; 08-05-2010 at 03:41 PM.

  5. #5
    Registered User
    Join Date
    Sep 2008
    Location
    Toronto, Canada
    Posts
    1,834
    It's an interesting problem: orientation in space. I wouldn't worry about accelerometer chips not being perfectly perpendicular. You can apply a matrix transform correction in software.
    How about some sort of compass and a sun angle detector? I realize a solid state fluxgate compass may be problematic in a noisy environment like a copter platform. But I've seen sun angle detector modules... just an idea that may be neater than gyros.
    Perhaps some level digitizers on 2 axes, plus the sun angle data. As long as the platform is guaranteed horizontal, the sun's angle should be all that is required to get orientation. Now for altitude, there may be accurate barometric gauges.

    Be advised that the type of parts you're getting are getting into scary territory that may set off alerts from homeland security. That's just my opinion. Maybe I'm overreacting.

    Anyway, sounds like a nice project. I wish I was there to help. If I had any time for hobbies any more.
    Last edited by nonoob; 08-05-2010 at 04:07 PM.

  6. #6
    Registered User
    Join Date
    Dec 2006
    Location
    Canada
    Posts
    3,229
    Thought about using a mobile phone to send text-messages with commands to the copter? IE go to gps-coordinate, stay at altitude, take pictures every x seconds and mms them back to the phone and stuff like that? Would be cool so you dont have to rely on the radio or wifi. I realize this is very much in the future but could be a nice addition if you succeed with the radio and wifi.
    I actually thought about that. Using cellular network for internet connection. Speed should be adequate. The problem is, I couldn't find a cellular chip that will connect to 3G, and is available to hobbyists. GPRS/2G speed is too slow for video streaming.

    Otherwise it would be a really cool idea!

    It's an interesting problem: orientation in space. I wouldn't worry about accelerometer chips not being perfectly perpendicular. You can apply a matrix transform correction in software.
    How about some sort of compass and a sun angle detector? I realize a solid state fluxgate compass may be problematic in a noisy environment like a copter platform. But I've seen sun angle detector modules... just an idea that may be neater than gyros.
    Yeah the perpendicular thing is not really a big problem. We can probably just live with the tiny error, too.

    A 3D compass can possibly work, assuming they exist, but I'm not sure if it will give me enough precision and update rate (at least 20Hz minimum to make it stable).

  7. #7
    Unregistered User Yarin's Avatar
    Join Date
    Jul 2007
    Posts
    2,158
    Very cool.

    I'm especially fascinated by the Gumstix (after looking it up :P).

    I'll be following your progress.

  8. #8
    Registered User
    Join Date
    Dec 2006
    Location
    Canada
    Posts
    3,229
    It's amazing how much they can cram into a computer that small. It looked even smaller in reality. About the size of an AA battery.

    The speed is like that of a PC from 7-8 years ago (Pentium 3 era).

    Only draws about 2W, too (with wifi off).

  9. #9
    Registered User
    Join Date
    Dec 2006
    Location
    Canada
    Posts
    3,229
    Update: mechanical design done.

  10. #10
    Registered User
    Join Date
    May 2006
    Posts
    169
    You should check out rcgroups if you haven't already. They had some very interesting designs, plus videos of how theirs got destroyed.

  11. #11
    Unregistered User Yarin's Avatar
    Join Date
    Jul 2007
    Posts
    2,158
    Maybe there's more to your plan than I know about, but your frame design looks terrible.
    -> You have a lot of mass there that doesn't need to be. You should streamline you design such that there isn't a bunch of mass around the outside, it doesn't help. Oh and just make the bottom layer a little thicker and forget the top one.
    -> It's flat. You should locate the blades at the top, and keep the 'platform' under the blades, not in the middle, this will help a lot with stability.

  12. #12
    Registered User
    Join Date
    Dec 2006
    Location
    Canada
    Posts
    3,229
    -> You have a lot of mass there that doesn't need to be. You should streamline you design such that there isn't a bunch of mass around the outside, it doesn't help. Oh and just make the bottom layer a little thicker and forget the top one.
    I was hoping to go for high strength (crash resistance), hence the relatively thick (~2cm) and complete outer rim. I don't think it will add considerable mass.

    -> It's flat. You should locate the blades at the top, and keep the 'platform' under the blades, not in the middle, this will help a lot with stability.
    My rationale for having the blades in the middle is to give them some protection (if it ascends or descends into something), but you are right, I haven't really thought about aerodynamics. I will remove the top platform if it significantly impacts stability.

  13. #13
    Officially An Architect brewbuck's Avatar
    Join Date
    Mar 2007
    Location
    Portland, OR
    Posts
    7,396
    Where is the gun turret?
    Code:
    //try
    //{
    	if (a) do { f( b); } while(1);
    	else   do { f(!b); } while(1);
    //}

  14. #14
    Unregistered User Yarin's Avatar
    Join Date
    Jul 2007
    Posts
    2,158
    Ah, I didn't think about think about the durability. Makes sense now.

  15. #15
    Registered User
    Join Date
    Dec 2006
    Location
    Canada
    Posts
    3,229
    Where is the gun turret?
    It's hidden. You need to type the cheat code "WEAPONS HOT".

Popular pages Recent additions subscribe to a feed

Similar Threads

  1. Problem Displaying a Struct
    By rockstarpirate in forum C++ Programming
    Replies: 16
    Last Post: 05-05-2008, 09:05 AM
  2. added start menu crashes game
    By avgprogamerjoe in forum Game Programming
    Replies: 6
    Last Post: 08-29-2007, 01:30 PM
  3. Dynamic Binding
    By gpr1me in forum C++ Programming
    Replies: 1
    Last Post: 03-24-2006, 09:01 AM
  4. Game Independent Anti-cheat Project Needs Programmers
    By GIA Project Lea in forum Projects and Job Recruitment
    Replies: 3
    Last Post: 09-15-2005, 07:41 PM