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 have two questions and apologize in advance for their newbie nature:
1) Can someone tell me a little more about the block for the PWM connection to the ESCs?
From photo1 of the schematic, it looks like there are four connectors in a block. Is the block made or is it something purchased (if so where)? Reading left to right, it looks like the first pin is for the PWM signal, the middle pin is power (only one used), and the last pin is ground. Am I close?
2) How is the connection from the battery to the four ESC's made? Is there a harness that is made or purchased (if so where)?
Any pictures would be great.
Thanks in advance.
James
Yun, your video looks very nice!! Probably your problems with yaw are because of the different prop in the back motor (This is a strange thing...) I think your motor could be bad or maybe you need to adjust the Throttle range of your ESCs so all have the same range.
Dody, I have one of the fist PPM encoders (output only 6 channels) and I have no problems with it... if you use the last PPM encoder code (wich I think that output the 8 channels) remember to change the #define MAX_CHANNLES constant.
Earl, bacause your design is bigger than original "mini" version, your PID values probably would be different, so take this into account...
Thomas, what do you think this code don´t work with counter-rotating props? We don´t need to do any modifications for this, the code should work (I have tested it)
Jose.
If I do not arrive there it will set out again to see JORDI.
In wait I will try to recover signal PPM on the coder of a receiver FUTABA.
@ + dody
We think a batch was programmed wrong. I sent it to Jordi to get reprogrammed.
Looking forward to getting it back so I can move ahead with the DarkStar.
You checked values of Acc_offset_x,y,z through serial monitor.
to find Acc_offset_z you should rotate 90 deg of your board and that's your acc_offset_z value
If you tune PID, read Jose's comment here. he explained it before
My quad also not quite well response, I'll try it.
Yun
I have one of the DIY Drones PPM Encoders that I bought a while ago and I just checked it with a Spektrum DX7 and an AR6110. I attached female headers to the bottom of the Encoder so that the Encoder stacks very nicely on top of the AR6110 without having to bend any of the receiver servo pins. Pin one of the Encoder, which is on the left end with the processor showing on the top, mates with the throttle servo output of the receiver and the rest of the receiver servo pins line up and connect from left to right on the Encoder. I attached the Encoder to the AR6110 and turned my DX7 on. I then applied power to the battery input of the receiver where upon the Encoder board blue led turned on and then began to blink indicating that the Encoder was encoding the servo outputs of the receiver. So I guess that this confirms that the Encoder works with a DX7 and a six channel AR6110.
Regards,
TCIII
I do not get to tune the PID.
The value of Yaw keeps my ArduIMU vary. To prevent this from happening. I need to change # define acc_offset_z 510 / / 501. right?
In your video yaw changed. Truth?
And finally. How to tune the PID?
Greetings from Spain.
I was trouble with motors perfomance. 4 motors had different characteristic.
so I changed prop size differently.
When I installed same size prop(5030), My quad was going backward.
so back prop was changed into 6050(I think 6030 is more suitable) and others were 5030
I changed something in the code, but it's my setting of ArduIMU.
I think it's different one you have.
that's below only but I am needed to tune PID also. I don't know how to tune heading lock, right now
---------------------------------
#define acc_offset_x 508//508
#define acc_offset_y 503//504
#define acc_offset_z 510//501
---------------------------------------------------
Yun from south korea
First congratulations on your cuadropter.
I'm trying to create one but I can not get it.
You need something in the code combination to achieve stabilization?
Any help would be welcome.
Greetings from Spain.
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