Developer

Indoor fun with a tiny ArduCopter quadcopter



Do you have an Ardupilot Mega and shield and want some fun for little money? check this tiny quad... my last drone in family...



Some specs:
- Size : 26.5cm (10.4 inches) from motor to motor
- Motors : 18-11 200kv 10 gram motors
- Props : 4x2.5 (standard CCW props)
- ESCs : Turnigy 6A
- Battery : 3S610 (or 3S800)
- Sonar : Maxbotics LV-EZ0 [optional]


The nice part about this frame is that it use standard kite parts, so it´s very easy to construct and it´s perfect for some radical tests.
Itried to find a bit different design that also make the quad less simmetrical (it´s very easy to loss the orientation with a quad) and I wanted to do as small as posible to flight indoors...
At this size and weight it´s very safe and robust also. The props use prop savers and this help a lot in crashes...
I am not very good writing... so I took a lot of photos during the build phase and I created a build log:
https://docs.google.com/document/d/1fIZL-Ca2fx2RPhBQLzoOdqdCuikXRKePwKbxDlJWiss/edit?hl=es

This code supports a sonar for altitude hold and also has a battery alarm (2 alarms).
Thisquad works with ArduCopter code, but because how main board is mounted, actual code doesn´t work. This is the code that I used with this quad :
http://code.google.com/p/arducopter/source/browse/#svn/branches/Arducopter_indoor
(as zip format:
Arducopter_indoor.zip )
note that this will be integrated on main Arducopter code. Now is temporarily in a branch.
ThePID gains are different than in standard ArduCopter, so you need to Initialize EEPROM on Configurator or put this ones manually:
-Stable mode: P : 4.8 ; I : 0.12 ; P_rate (D in configurator) : 0.4 ; Yaw : (4.5 ,0.15 ,2.8 )
-Acrobatic mode : P : 0.75 ; I : 0.1 ; D : 0 ; Yaw : (2.4 ,0.2 ,0 )

OK, but was all so perfect like in the video? I don´t believe that...
Yes, you are right, but fortunately this design is very crash resistance... and this part is also fun...


After all this battles I only needed a few drops of ciano in the crash with the lamppost :-)

What´s the real size?


On center, standard arducopter frame, on left, old ArduIMU quadcopter part III, on right-top this project.

And what about the automatic aerobatics on video?
I am starting to test a new function to do automatic aerobatics (Automatic Aerobatic Procedure). The idea is that you enable this function with a switch in the Tx to make an automatic predefined aerobatic and then automatically recover to a stable mode.
Thisis actually a proof of concept but works very nice. One limit here is the maximun rate of the gyros, in our case 500deg/s. If we exceed this, the IMU get confused...
An interesting point to note is that the IMU doesn´t loose the orientation in this hard movements...
Thestory is that I have never feel too much confidence doing flips manually with quads. Then I start thinking that with an automatic code we can get a precise timing and controled movement so maybe this could help to do better aerobatics. I started testing this function outdoor, on an open field but I was improving the code and got more tightly maneuvers, so tight, that I ended up doing flips with a quad inside my room!!!


Here is the code I was testing : (AAP function:
AAP.txt )
I implemented this functionality as a state machine where there are three kind of states:
- fixed commands for a limited period of time. (example : Apply a throttle command)
- fixed commands until we reach some IMU state (example : roll until we reach a certain angle)
- And a mix between this categories and a control (example : Throttle command + stable mode on roll, pitch, yaw)
There are many things to test and improve here but the basic concept works very nice...

If I can get a bit of help from a friend, I will probably made a carbon fuselage for this prototype...

Enjoy this “Science & Fun” mix...

Jose Julio.
Arducopter Team
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Comments

  • I also built one of the ones like in the original post here but found it too flimsy and wanted something I could add more to like a very light FPV cam and tx or go pro. Your build with cf and spacers is exactly what I was planning. I ordered some motors (haven't arrived yet) and will match it with 8x4.3 props. Motor is Turnigy Park300 Brushless Outrunner 1080kv. I know the quad will be a little bigger but that is ok. I might also try it with the original kit frame from jani and just remove the legs, motor mounts and cut the arms shorter and take off the electronics protection and other non essentials. I did that with the 1811 motors and it would hover but only fly a few minutes because it was too heavy.

  • @Robert - In my experience, the little 18-11 2000kv motors just can't spin the little 4x2.5 props fast enough on 2s.  I can hover and fly, but it's near full throttle.  They are limited by the kv, not power.  Going to a 6x3, you can get enough thrust with 2s rpm levels.

    I like the 4x2.5's on 3s best.

  • Judging from the datasheet of the Turnigy 2211-2300 motors and from putting the numbers into the ecalc.ch calculator, this motor is not designed to turn a 6x3 prop on 3S. Motor temperature will be too high and the motor windings might be damaged. Also, I wanted to limit the current draw so that the Turnigy Plush 6A ESCs can still handle it.

    It flies nice with the 6x3 props on 2S and has good endurance with the 2100mAh battery I'm using, but on a 3S battery it accelerates much faster and is just more dynamic. It simply depends on what kind of flying the user prefers.

  • Jan:  Very cool. I have also built a little carbon fiber mini quad, but it's not flying stable yet. Please tell me a little bit more about why you use 6x3 props with the 2s battery and 5x3 props with the 3s battery. --Robert

  • Guys, check out my newest iteration of the miniquad idea! It is slightly scaled up in strength, but motor-motor distance is still 260mm, so about 10.25 inches. Made from 1mm and 1.5mm carbon sheets, aluminum screws, plastic spacers and standoffs. Motors are now Turnigy 2211-2300 turning either 6x3 props on 2S or 5x3 props on 3S. Overall weight with either a 1350mAh 3S or a 2100mAh 2S battery is 375 grams.

    3692288985?profile=original3692289340?profile=original

  • Everyone, I don't know if this is appropriate to post here, but I completed my new mini quad frame and now I'm thinking about selling my previous version. Just the frame with motor mounts, none of the electronics. I also have a bunch of extra motors. Email me if you're interested!

    3692283483?profile=original

     

  • By the way, what we call "motor mounts," the kite world calls "Stand Off Connectors."
  • @Dane,

    None that I could find and I looked, emailed and called probably 30 stores across the country, basically any kite store I could find.  Seems like the US has only those motor mounts and this pic explains the problem (sorry for the quality):

    apa-motor-mounts.jpg

    Here is the link to Jan's motor mounts - again I thank you Jan for the files :)

     

    Bob

  • There are kite parts available in the U.S. that you can use for mounts that approximate the original build. I've used them on my mini quad, which is shown here http://www.diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A.... If you look through the comments on that post (a few pages into the comments), there is a place where we are discussing the kite parts I tried. This may help you find the right parts you need.
  • gotcha well thanks for the response Jan!

     

    would you mind sending them to daign2002 at gmail dot com?

     

    I'll try and find someone willing to make mounts.

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