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What laptop are you using with Mission Planner?

Started by DG. Last reply by Emin Bu 1 hour ago. 11 Replies

My laptop is dead; i5 HP 17". The family is tired of me borrowing theirs. After using Tower for the last several weeks and discovering "issues", I decided to go back to lugging around a laptop or…Continue

Test Stand Setup?

Started by Robert Giordano. Last reply by Darius Jack 11 hours ago. 44 Replies

I've put together a test stand for my 450 class quadcopter running APM 2.6/Arducopter 3.2. After a recent crash where my quad suddenly fell out of the sky, I want to run some tests on the stand,…Continue

APM negative altitude

Started by Antti Latva. Last reply by Antti Latva on Monday. 3 Replies

Like the title says i am getting negative altitudes trying to fly my APM 2.5 hexa. I admit it has taken a few hits in the past but the problem appeared suddenly after successfully flying it the day…Continue

Hexacopter does not fly like before a crash

Started by Bernardo. Last reply by Bernardo on Sunday. 18 Replies

Hi,after a crash (beginner) I fixed a few broken things.I also flash the APM 2.5 new because I changed too much parameters.All mandatory things and settings and calibration done.Now, during my first…Continue

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Comment by Andrew McKinstry on December 17, 2012 at 10:10am

Hello.. Shiny new hexa with all the toys about to leave bench (I hope).. however prop clearance issue! Or am I missing something.. 880 motors 11x4.7 props

thanks

Comment by avionics on December 9, 2012 at 9:45am

2012-12-09%2020-01-10.tlog

 

Hi Guys

I was in the middle of tuning for my Loiter and suddenly the quad started coming down out of control and crashed. Luckily no damage but it went out of control. this is the log i appreciate if any one can help and see what went wrong. thanks

 

2012-12-09%2020-01-10.tlog

 

Comment by avionics on December 7, 2012 at 8:16am

OK I got the Loiter going almost good. I had problem with my CH_6 knob on TX. fed the info directly from the ground station. all good for now. Thanks.

 

Comment by avionics on December 6, 2012 at 10:26pm

@Randy

Randy thank you for the response. Frankly I dont really know what to look for in the log. any idea what i should expect in the log? sorry I have never done this before.

Comment by Randy Brazeau on December 6, 2012 at 11:38am

@Avionics

Have you reviewed the logs? That would be a good starting point to see what is happening.

Randy

Comment by avionics on December 6, 2012 at 11:04am
I have a H.A.L quad by hobby king with 1200kv motors and freshly assembled. It flies beautiful in stablise and alt Hold and when i try to loiter it doesnt hold its position. The GPS both LEDs are locked and steady before i start. It drifts and loses altitute very slowly. Tried playing with PIDs but no luck. I ran out of ideas appreciate if anyone can throw some light. Does the WP loiter config PIDs have any effect whilst on loiter or it is only for when on Auto mode? Thanks for the help in advance.
Comment by Chris Gough on November 29, 2012 at 1:36am

@Shayam, if you want to experiment with quaternions, DCM, euler angles, etc. you might want to check out the various pluggable AHRS subsystems in paparazzi.

http://paparazzi.enac.fr/wiki/Subsystem/ahrs

Comment by Shyam Balasubramanian on November 29, 2012 at 1:24am

@Randy, Thanks for that nice explanation on accelerometer with quads! Now, my understanding gets better.

I would want to try out Quaternions once myself, it seems different people are having different opinion. My friend, who works purely on Quad uses quaternion. He mentioned to be that it was 'much' faster than DCM. But, since truth is one but scenarios differ, I will ask him if he can lend me some benchmarking ;)


Developer
Comment by Randy on November 29, 2012 at 1:15am

@Shyam re Quaternions,

     There's a thread by Bill Premerlani re DCM vs Quaternions.  My understanding is that they're equivalent.  II think perhaps DCM is faster but maybe not, i'm not sure.  I don't think it's as simple as one has 4 elements so it's faster than the other that has 9.

     When the copter/plane accelerates in any direction, the accelerometers sees this.  The problem is that we generally use the accelerometers to tell us which way is down.  So any acceleration of the copter/plane has the potential to throw off our attitude estimate.  Normally the accelerations are short-lived so they don't cause much problem but if they're long lived (for example you're constantly travelling in a circle) it can be a real problem.

-Randy

Comment by Shyam Balasubramanian on November 28, 2012 at 3:51pm

@Randy,

Thank you for your thoughts on implementing quaternions. I have a question, quaternions are supposed to be faster as they use 4 elements unlike DCM which uses 9, and does not suffer gimbal locks (even DCM does not, but one should know how to avoid it there though), it must result in faster computation right?

And what does "the centrifugal (centripetal) force which can throw off the accelerometers" means?

Thanks!

 
 
 

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