Hello, I am tuning a larger 4 arm octocopter. It flies well in manual flight mode, and I can not see anything drastically off with the PIDS, https://review.px4.io/plot_app?plots=pid_analysis&log=d9cc7634-8c02-4f0e-81c0-56526c2d7d0c but once I move to position flight mode I am seeing strong oscill…

We got this working. Here are the 3 things that we did Ensured that there was no glass in front of optical flow sensor (there can be glass, but ours was smudged a bit so we just took it off) Hard Mounted: we have the flight controller on some heavy vibration dampeners. The theory is that this scre…

I take a look at the velocity setpoints and response, and I can see they are very far apart [image] but i have never seemed to tune the velocity controller before, so I am hesitant to point towards it

It looks like pixel flow is minimal, might not be but the logging rate is low. The the gyro oscillations are dominating the velocity calculation. [image]

We have a piece of glass that is over the optical flow sensor. we are going to try and remove that to see if it is causing any unintended reflections.

Looks like it might have been the glass Before: [image] After: [image]

Solution: The glass had a smudge on it. After removing the glass entirely our pixel flow rate went up, and the drone is now stable in flight @AlexKlimaj Thank you for your assistance!

This solution seemed to work to get rid of large oscillations, but we seem to still have a problem with position hold and smaller oscillations. Alex indicated that we should NOT be dampening the arkflow. So we are going to hard mount it to the airframe to see if this resolves our issue. Alex was ab…

Wanted to show here what a healthy optical flow chart looks like [image]

Optical Flow Oscillations

PX4 Autopilot

AWilkins_Ascend January 24, 2024, 5:13pm 5

Looks like it might have been the glass
Before:

After:

Large velocity divergences with optical flow - velocity estimates and setpoints oppose each other causing crashes

Topic		Replies	Views
Large velocity divergences with optical flow - velocity estimates and setpoints oppose each other causing crashes PX4 Autopilot	9	126	December 16, 2025
Slow oscillation on position hold PX4 Autopilot	5	1042	August 29, 2023
Optical Flow oscillating position v1.14	13	1773	October 13, 2023
Quadrotor indoor position hold with optical flow and mocap PX4 Autopilot	5	2355	June 6, 2017
Ark optical flow with px4 1.13 position hold PX4 Autopilot	0	414	February 4, 2023

Optical Flow Oscillations

Related topics