Hi all,
I have finished my second quadcopter with ArduIMU. This time is a "mini" version with only 28cm from rotor to rotor and has the new Jordi´s magnetometer integrated!.
This tiny machine is fantastic, with a great stability. Look at the hands-off part of the video inside house!!
Very funny :-) Video:


Specs:
Motors: 1811 2000Kv 10grams brushless motors
Props: standard 5x3
ESCs : Turnigy 6A
Batt : 2S610 Lipo
Weight (RTF) : 180grams
Again it´s a very cheap and easy setup. Because I use standard propellers I mounted left and right motors with some twist. I´d really love arduIMU flat hardware...


Look at the PPM output Rx, Is this a new 2.4Ghz receiver form DIYDrones?
No, it´s a "lighweight" (4.1grams) mix between Spektrum AR6110 Rx and Jordi´s PPM encoder. This is nice for DIY projects...


The code is improved from the old version. This one has the magnetometer integrated so now we don´t have drift
on yaw axis, better implementation for the D term on the PID controler (more responsive to user inputs), same safety improvements, fast ESCs update rate (166Hz), new PID tunning...

But this history had an interesting lesson for me... The prototype you see here are really the second one, the first one was a dissaster... (flys bad...)
Do you want to know the "small" difference between them? This:


For the first one, I use an U shaped aluminium arms to save some weight. Well this shape is very bad in torsion and generates a lot of vibrations. This vibrations saturate the gyros (our gyros are quite sensible on vibrations because the low internal resonant frecuency). You could see here a graph of the gyro output value vs Throttle and you can see clearly the effect...


I change the arms to the square shape (8x8mm) and problem gone!! Perfect stability... :-) Vibrations are our enemy (Lesson learned)

Here is the new source code: Quad1_mini_20.zip (see notes.txt inside)
Schematic (conections): Photo1 Photo2
Old post (first version) here

New ArduPilot Mega will be a perfect platform for Quad´s also, so stay tuned...

Jose.

Views: 33043

Tags: ArduIMU, IMU, arduino, magnetometer, quadcopter, quadrotor

Comment by Nawaf Sharaf on June 8, 2010 at 10:22am
Cool..thanks YUN..!
Comment by White Gollum on June 14, 2010 at 8:55am
Thanks for the tips Yun, after recovering all the inputs, I decided to start the project. I will be documenting all the steps.
Unfortunately the arduimu and the PPM encoder are currently out of stock, so I have to wait.

Nawaf, for me it is enough difficult to get the Quad part 2 flying, so when I get it, I will consider moving to the part 3.

Greets
Comment by DODY on July 7, 2010 at 10:34am
Hello,
@jose and @Yun,
here my first tests with the quadcopter, it is really unstable. (see video)
here the values which I obtain (see file).
Which corrections can I make?
DODY
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Comment by DODY on July 7, 2010 at 10:44am
Comment by Earl on July 7, 2010 at 11:03am
@DODY
What format is the document in ?
Tried to open in wordpad but is unreadable.
How about Adobe ?
Earl

Moderator
Comment by Morli on July 7, 2010 at 11:16am
Earl, it opens in MSword
Comment by Yun Youngjun on July 7, 2010 at 6:02pm
Hi! Dody
What's your motor?
ESC calibration manually?
Left, right motor tilted like upper picture? When You are using different motor and prop, tilted angle was slightly bigger.
I saw your serial monitoring values, you need to change offset value acc_offset_x &acc_offset_z
You should change acc_offset_x and acc_offset_z according to jose's comment.
output vlaues of first & second colum are close to 0, that's good

and tx trim adjust.

When I controlled my quad, she's very unstable so cut the prop and balancing thrust
I don't know why that happened.
If you use jose's spec I think that's ok.
of course on the ground it's unstable a little bit but she was in the air , she's very stable.


Yun
Comment by DODY on July 8, 2010 at 12:46am
Hello to all,
@Earl, my document opens with WORD.
@Yun, my engines are TURNIGY C1818-3500 and I calibrated the ESC with the pocket TURNIGY and they have the program by defaut.
I am going to resume the advice of José for the offset X and Z.
@+
DODY
Comment by Yun Youngjun on July 8, 2010 at 2:01am
Hi! dody
Your motor's kv is very big..it's double of mine. but you'll try
You should callibrate ESC manually with TX refter to jose's comment.
It help to adjust same throttle range of each ESC.
could you check rpm of each motor in same throttle?
Comment by DODY on July 10, 2010 at 5:17am
Hello Yun,
I put the same engines that you and I changed the offsets acc X and Y to have 0 there, but when I move arducopter, the 2 columns do not return to 0, when I carry out my tests arducopter want to turn in round and want to leave in diagonnal.


can be that I do not make well the reglage offset like José, can you explain me how you make step by step.
thank you
RV.

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