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)
Old post (first version) here
New ArduPilot Mega will be a perfect platform for Quad´s also, so stay tuned...
Jose.
Comments
I think you need to do fine tunning.
You are almost close to the goal.
Yun.
here is the quadcopter fly, it is not yet very stable.
that me council you so that quadcopter is less sensitive?
I put the exponential one on canal 1 and canal 2 but there remains unstable.
in a friendly way
DODY
what is wrong with that configuration ?
I've just finished building of my ArduIMU JJ quadcopter and start testing.
what's strange copter reacts properly for pitch and yaw but not roll.
is it normal in AP mode 2 (stabilization assist mode) ?
regards,
cholo
also mine valuses are a little bit changed not return to 0.
My first flight was the same like you.^^
I found that one motor was over power so I cut prob a little.
and then it's controlled but more trim needed. later I changes all motor like jose's 1811 kv2000
Dody! all motor has not a same characteristic.
In case of Mikrokopter or other Quadcopter They do well flight having different Props and similliar motors
but mini ArduIMU copter did not. so very careful.
you must clear below..
1. ESC manual calibration. what is pocket turnegy?
2. Left, right prop Tilted correctly or CW,CCW prop?
3. arduIMU copter is very senstively moving according to what's your motor, prop and vib, prob balance.
4. 1811 kv2000 motor is good. recommended
5. mag sensor attached?
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.
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?
@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
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
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