Problems with BMA020 and/or Nunchuck

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Problems with BMA020 and/or Nunchuck

Postby herzjung » Tue Jul 05, 2011 8:22 pm

Hello,

On my Quadrocopter I have to use suprisingly low PID settings (1,3 / 0,017 / 2).
With this settings my Quadrocopter is flying satisfactory.

When I connect an ACC being it BMA or Nunchuck I have almost no control when I a tivate them (stick movement does almost not effect the flying). When I turn them off via AUX everything is fine.

I think the reason is in my low PID parameters - what can I do?

Regards
Peter
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Re: Problems with BMA020 and/or Nunchuck

Postby captaingeek » Wed Jul 06, 2011 3:42 pm

How's it fly by the default settings? Maybe try go back to default, Lower I and increase P a bit.
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Re: Problems with BMA020 and/or Nunchuck

Postby herzjung » Fri Jul 08, 2011 7:55 am

When I use default values the Quattro flipps at any start attempt instantly. I can only fly it with P values lover than 1.4.

I have thaought about the reasons. It can't be the motors and props, I use the same on my Tri with default values. The reason my be in the ESCs I use Mystery 30A (yellow) and have not changed any parameter. The Frame is reatively small with 45cm.

Any suggestions?
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Re: Problems with BMA020 and/or Nunchuck

Postby Am0s » Fri Jul 08, 2011 3:44 pm

I also have the same issue with my tri setup. (P 1.4, I 0.005, D 1) anything higher (or default) ends is oscillation and flips. I am using Turnigy motors (800kv) and ESC's.

I think it is related to the gyro, i was running WMP clone (No ACC installed yet) but as of last night have connected directly to the ITG3205. Will test again this weekend and post back results.
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Re: Problems with BMA020 and/or Nunchuck

Postby Am0s » Sun Jul 10, 2011 7:06 pm

Have now direct connected the ITG3205 and also direct connected the NK (clone with KXSC4 accel) to A1-A3 using the ADCACC setup.

Just test test hovered stable at (3.2, 0.025, 4). some fine tuning still needed but a noticeable improvement on the PID values.

Hope this helps.
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Re: Problems with BMA020 and/or Nunchuck

Postby Am0s » Mon Jul 11, 2011 10:15 pm

False positive! had a chance to get some FF in today but was unable to maintain a hover at these settings (3.2, 0.025, 4). pitch/roll oscillation and the od unexpexted half flip :roll: (Wind was gusting a bit)

Re tuned PID down to about the original stable settings (P 1.4, I 0.005, D 1). No more unexpected pitch or roll but still retain a small rear motor oscillation in hover and slow FF?

Any idea on why the PID settings are so low? and why there is a small pitch oscillation. Sensor/code related or possibly vibration/batter CoG?
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Re: Problems with BMA020 and/or Nunchuck

Postby Rob » Tue Jul 12, 2011 10:42 pm

If PID settings are low I think the problem are the ESC´S.
(If frame is without vibrations)
what kind of ESC you use? (type and settings)
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Re: Problems with BMA020 and/or Nunchuck

Postby Am0s » Thu Jul 14, 2011 1:12 pm

Turnigy Plush 30A
Start Mode= Normal
Timing Mode=High
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Re: Problems with BMA020 and/or Nunchuck

Postby cob » Thu Jul 14, 2011 7:14 pm

I would first check for any vibrations chasing them out. Second point is true : I had 2 Nck clones offering... just nothing! As I bought by mistake a Wii remote instead of a Nck, opening it I found a nice ADXL335 inside. Those are the recent Wii remote where an ACC is included. Connecting directly the ACC to A1 A2 and A3 I got good results. For those who whant to connect an ADCACC on A1-2-3, check the datasheet or measure the ADC value coming out of the ACC. Change the ACC_1G accordingly in the IMU.pde . See my project in IDEA posts on how to read ACD data from an analog ACC, viewtopic.php?f=7&t=497
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