Throttle and Alt-Hold PIDs

So I've been unhappy with how aggressive the throttle is on 2.8.1, plus my quad sinks, and climbs, and sinks and climbs, over and over. And I feel like I'm often giving it waaaay to much throttle just to hold altitude. 

So in the new Arducopter Pids screen I cranked up both Altitude Error P and Thrust Rate P, from 300 to 330.

I was greeted today by really nice throttle response when the quad leapt into the air with wild abandon.

I switched to ALT-Hold from stabilize mode. 

As I floundered about fighting the stupid wind gusts (shouldn't have flown really, to gusty), suddenly the quad stopped obeying me and gyrated violently, I switched back to stabilized, hit disarm and dropped the quad so it wouldn't flop itself into the lake. It was only a meter or two in the air.

So I have a couple questions. 

Is Throttle rate P the correct thing I need to adjust so I get better throttle response?

Is Altitude Error P what caused my Death Wobble?

3690972303?profile=original

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  • Hi I am a very new quad flyer with a 3dr Aruducopter kit straight from the box. I apologise if this is the wrong place to post but I have been following the “damping “thread with interest

    . My machine appears to be fine in hover, stabilise, rtl etc but very twitchy in Alt hold. No tuning done yet so default 2.91 values.

    I have attached a log file and wondered if someone could have a look analyse and come back with a few pointers?

    As I said very new and on a big learning curve on flying, log analysis, tuning and everything else!

    Thanks in advance

    Tony

    2013-03-07 12-47 1.log

    https://storage.ning.com/topology/rest/1.0/file/get/3692644090?profile=original
  • Much better. I think jacking up the Alt-Hold IMAX really helped. Lowered the Throttle Rate P a big chunk too. Now it does terrain following about a foot off the ground. 

    When the ground descends, the copter takes it's time to drop down and follow the topography, but as the ground climbs (flying up a hill), the copter climbs right up maintaining a foot or two height. It's a beautiful thing to watch. 

    Gave up on worrying about the data spikes in Sonar. Just copied Randy's install, used a cable with 3 separately shielded wires (A/V cable), and mounted it between the rear motors. Seems to work well enough. 

    3692543608?profile=original

  • I should check the wiki before posting sometimes. Sorry. 

    http://code.google.com/p/arducopter/wiki/AC2_alt_hold_PID

    Still wondering about the throttle response question though. 

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