Quad Bounces in Alt Hold mode (Vibes good?)

ArduCopter Copter 4.4
1

Hello my fellow enthusiast

(Build)
FC Stack: SpeedyBee F405 V3 with SpeedyBee BLS 50A 4-in-1
Motors: Xing 2207 2450KV
Props:Gemfan 5552 3 blade
GPS: HGLRC m100

I’m a first time poster and having trouble with bouncing in alt hold mode but not in stabilize I don’t think it’s due to vibrations but I’m also not 100% sure on how to read the logs, as soon as I switch to alt hold mode the throttle input log seems to oscillate and I’m not sure why pictured below

THRin VS THRout
THRin VS THRout1299×731 13.2 KB

Here are Vibe logs they seem to be within normal levels which are below 15m/s/s according to https://ardupilot.org/copter/docs/common-measuring-vibration.html pictured below

vibe_logs
vibe_logs1299×731 16.8 KB

Here are my logs for comparing the attitude estimates (i.e. each AHRSs or EKFs) the pitch and roll seem to be within a few degrees of each other respectively which is good according to https://ardupilot.org/copter/docs/common-measuring-vibration.html pictured below (I dont have the greatest understanding of EKFs and AHRSs)

AHR2vsXKF1
AHR2vsXKF11299×731 14 KB

And here are my barometer and altitude logs

Alt and Barometer
Alt and Barometer1299×731 13.8 KB

Im not sure if I’m missing anything or if someone would like to see more information please let me know wind conditions were extremely calm by the way I can try to make a video of it flying later if anyone thinks that would help also any input helps thanks :saluting_face:

2

There’s a tune/setup issue. Post the .bin log of the flight and you can get more help. Videos are often little help, but a couple of pictures of the build might be useful.

3

@Allister Thanks for the reply first off and
here is the BIN. and quadcopter in all her glory excuse the wire management lol
https://drive.google.com/file/d/1-FNsmxp40rFJPRzy9r3lCIH1dTRmnscK/view?usp=drive_link

IMG_2853
IMG_28531536×2048 318 KB

IMG_2855
IMG_28551536×2048 259 KB

IMG_2856
IMG_28561536×2048 278 KB

Thanks for the input much appreciated

4

There’s a lock on the download link. Can’t download it.

But in the mean time, the cable management might be part of the issue. More specifically the cap and the VTX antenna will be giant spring boards bouncing off the back. Look into the Chris Rosser videos where he talks about the effects of how a VTX antenna freely mounted like that can show up in the IMU data. Secure the antenna and the cap. Make sure no wires are bouncing on the FC. The wires shouldn’t pull or be stressed, but they shouldn’t be flopping around.

1 Like
5

@Allister the link should be accessible now and I Secured the wires and added support to the Antenna to no avail it gets the exact same results

6

The outputs are oscillating badly. It’s one of the 1st things you check on 1st flight after setting the Initial Parameters:

RCout
RCout1920×570 147 KB

1st set these:
PSC_ACCZ_I,0.2
PSC_ACCZ_P,0.1
Then increase the Rate Pitch/Roll P&I values to something reasonable. Try .04
Set these and then do a short hover flight in AltHold to collect data to configure the Notch filter:
INS_LOG_BAT_MASK,1
INS_LOG_BAT_OPT,4
No ESC telemetry?

Edit: I had a typo on the PSC_ACCZ_I parameter I noticed and fixed it (was 0.02). That would have been a big problem!!

1 Like
7

@dkemxr thanks I really appreciate all the help I made those changes and the PID’s and did a short ALT Hold flight to collect some data that did get rid of the bouncing also now I have to do some research on the notch filters because I’ve never dealt with them before.
Yes the 4-in-1 does support esc telemetry
Ill post logs of flight a little later also

8

OK, RPM isn’t being logged and you will want that for the Notch Filter if available.