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

  • You'r so awesome Jose, keep up good work, big fan :)))
  • You have small mistake: 2000kv motor
  • Developer
    @Frank, yes you need to adjust the sonar scale factor.
    In ArduCopter.h you have this line
    #define SonarToCm(x) (x*0.22)
    You need to adjust to the new sonar model.
    http://factor.In/
  • @Jose. I found the problem they have send me a XL version of the sonar which the output voltage is different of yours. Is there a scale factor so that I can still use this one?.
    Yours: 5V yields ~3.8mV/cm.
    (my sonar) the XL: 5V yields ~4.9mV/cm

    //Frank ..
  • Developer
    @Mathew, it probably worth a test...
    @Fran, you could first make sure if you are geting good values from sonar. You can uncooment the line
    //Serial.println(Sonar_value);
    in Arducopter_indoor.pde and use the serial monitor of Arduino IDE to see the sonar values...
    In this sonar model, when you connect the battery there should be no objects near the sensor in order to initialize properly (see manufacturer datasheet).
    Hope this help
  • @Jose, If I enable the sonar in the code and arm the motors the green led will blink but if you throttle up the motors are not running.
    If you put stable mode ON the motors will run.
    If I switch Automatic mode ON (I don't have IR! only sonar) the quad will go wild!.
    Is there something I do wrong? (if I uncomment #define IsSonar, the everything is oke)

    //Frank ..
  • @jose_julio Thanks for that, outside this discussion, but i wonder if the increased efficiency of the DD props would outweigh the lost thrust due to the motor angle compensating for tourque. The DD props over the SF props are in the region of +20% on a 1300 kv motor on 3S ( SF prop drew 13 amps, the DD prop 10.5 amps, with more thrust than the SF)
  • I think you know what I mean ;)
    just keep it in the normal range (6-20V DC)

    I'm working on this Quad, too
  • "you can put in any voltage and it feeds 5V to the board (only on th +/- pins)"

    Can you put 220V Ac?? :))))))

    Any can be a lot!!!!!
  • Wow! that is amazeing now all it needs is "swarm" capibilety
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