Posts: 9 Threads: 3 Likes Received: 2 in 2 posts Likes Given: 1 Joined: Apr 2017 Reputation: 0 15-Jun-2017, 07:10 PM (This post was last modified: 16-Jun-2017, 09:08 AM by Frosty.) Hi gals/gents,
I've encountered a problem when attempting my first actual flight. When adding throttle, or switching into air mode, the motors start twitching strangely. During troubleshooting I noticed Betaflight shows the gyroscope detecting strange twitching, so I think that's the culprite. Initial tests showed the drone working fine, but I'm afraid that I may have fried the gyro or FC during a minor accident. Adjusting throttle in Betaflight doesn't result in any twitching, so Im leaning toward the FC being broken, or being mis-configured.
Is there anyway to diagnose if the gyro is faulty, other than swapping the FC? Do you have any other ideas what can be the the reason of these motor twitches?
I made sure that the motor screws aren't too long, the ECS are calibrated as is the FC. All soilders look fine.
My setup is: Emax2205, DYS XS 20A, REVO STM32F405 with Airbot F4 firmware, I also tried with Revo FW, same problem.
Here are some videos showing what's going on:
Start-up:
Static drone, view in Betaflight:
Here is the throttle controlled via my Taranis, up to 0:17 it armed, after that its airmode:
And here is a test I did some time before I had a small crash:
![[-]](https://intofpv.com/images/collapse.png) • Posts: 1,149 Threads: 50 Likes Received: 704 in 450 posts Likes Given: 1,189 Joined: Sep 2016 Reputation: 30 You say there's no twitching when "adjusting throttle in betaflight". When only using motor tab (not armed by tx), then there is no PID activity.
So it sounds like it's just excess noise messing with the PIDs. Adjusting filters will not help much, best bet it to softmount the fc or/and motors i guess.
Could also be electrical noise messing with the gyro. Low-ESR caps between escs and PDB can help in that case. Posts: 12,099 Threads: 125 Likes Received: 3,739 in 2,836 posts Likes Given: 99 Joined: Feb 2017 Reputation: 388 What is your min_command and min_throttle setting? • Posts: 9 Threads: 3 Likes Received: 2 in 2 posts Likes Given: 1 Joined: Apr 2017 Reputation: 0 16-Jun-2017, 01:25 PM (This post was last modified: 16-Jun-2017, 01:27 PM by Frosty.) (15-Jun-2017, 08:23 PM)fftunes Wrote: You say there's no twitching when "adjusting throttle in betaflight". When only using motor tab (not armed by tx), then there is no PID activity.
So it sounds like it's just excess noise messing with the PIDs. Adjusting filters will not help much, best bet it to softmount the fc or/and motors i guess.
Could also be electrical noise messing with the gyro. Low-ESR caps between escs and PDB can help in that case. I unplugged every lead from the FC, and the only connected cable is the USB one I'm using to connect to Betaflight. I'm still getting twitches on the gyro... (15-Jun-2017, 11:31 PM)voodoo614 Wrote: What is your min_command and min_throttle setting? min_throttle is set at 1020, min_command is at 1000 • Posts: 1,149 Threads: 50 Likes Received: 704 in 450 posts Likes Given: 1,189 Joined: Sep 2016 Reputation: 30 16-Jun-2017, 07:36 PM (This post was last modified: 16-Jun-2017, 07:36 PM by fftunes.) You are right, that looks bad. Unless you have a real noisy desktop...  jk. Just unlucky i guess... glad my revo FCs work all fine so far. • Posts: 1,773 Threads: 30 Likes Received: 1,199 in 755 posts Likes Given: 714 Joined: Oct 2016 Reputation: 45 OK, this sounds crazy but guys have posted this and apparently it works. Take your flight controller out and whack it on your workbench a few times as it's possible your gyro's stuck. It must be true and it must work, because I read it on the internet. Posts: 2,416 Threads: 51 Likes Received: 1,861 in 1,175 posts Likes Given: 3,315 Joined: Mar 2016 Reputation: 74 (16-Jun-2017, 08:41 PM)RENOV8R Wrote: OK, this sounds crazy but guys have posted this and apparently it works. Take your flight controller out and whack it on your workbench a few times as it's possible your gyro's stuck. It must be true and it must work, because I read it on the internet.  And if that doesn't work, spit on the back of it and kick it (at least the kicking part worked for my dad on our old B&W TV..)  (Of course don't really do this until you've exhausted all other possibilities....) • Posts: 9 Threads: 3 Likes Received: 2 in 2 posts Likes Given: 1 Joined: Apr 2017 Reputation: 0 Thanks guys  I'll try the whack thing. With frustration building up over this, it was bound to happen anyway Will let you know if it helps! Posts: 1,773 Threads: 30 Likes Received: 1,199 in 755 posts Likes Given: 714 Joined: Oct 2016 Reputation: 45 And if it does work, Sloscotty owes me an apology bwahahaha • Posts: 2,416 Threads: 51 Likes Received: 1,861 in 1,175 posts Likes Given: 3,315 Joined: Mar 2016 Reputation: 74 Yeah, but if kicking it works...... • Posts: 1,149 Threads: 50 Likes Received: 704 in 450 posts Likes Given: 1,189 Joined: Sep 2016 Reputation: 30 17-Jun-2017, 08:28 PM (This post was last modified: 17-Jun-2017, 08:31 PM by fftunes.) Hm i just read about some rx code errors again, did you check if there is any twitching visible in the receiver tab? • Posts: 2,286 Threads: 38 Likes Received: 1,527 in 995 posts Likes Given: 1,881 Joined: Apr 2016 Reputation: 72 (16-Jun-2017, 08:41 PM)RENOV8R Wrote: OK, this sounds crazy but guys have posted this and apparently it works. Take your flight controller out and whack it on your workbench a few times as it's possible your gyro's stuck. It must be true and it must work, because I read it on the internet. The only thing that's likely to do is destroy the gyro once and for all. IMU chips have a maximum shock rating of 10,000g for 0.2ms when not powered. Whacking your flight controller on the bench is likely to exceed that. • |
