I am flying my 3m 20kg quadplane VTOL (Long Endurance VTOL Drone | 23KG MTOW | 2.5Hours Endurance) in AUTO mode, and every single time when in AUTO mode the plane pitches down after the transition from VTOL to fixed-wing has been completed, dropping up to 80m in altitude (from 120m to 40m, which is the Q_ASSIST_ALT).
I tried changing Q_ASSIST_ALT to 70m, but then the pitch down and altitude drop happens anyway.
I am almost certain that this is not a ‘physical’ / hardware issue, because the transition works perfect when not in AUTO mode! For example, when I am hovering in QLOITER and then switch to Guided mode, or when I am hovering in QLOITER and switch to RTL mode, the transition from VTOL to fixed-wing works perfect,and there is barely any altitude loss or pitching down after the transition (max. 2m).
Secondly, I am almost sure this is something to do with AUTO mode. Firstly, because this issue only occurs in AUTO mode, but secondly this is because when I change the altitude of waypoint 2 to be above (100m) the VTOL_TAKEOFF altitude (85m) , the altitude drop does not happen between the VTOL_TAKEOFF and waypoint 2. Instead, it happens between waypoint 2 and waypoint 3 unfortunately. But again, this shows this is not a physical issue (e.g. the plane cannot maintain altitude) and that this is something to do with how the plane navigates in AUTO mode.
I am attaching my parameters here, along with the logs from the flights.
We are working on a medical drone project for healthcare, so any urgent help for debugging this would be much appreciated! Thank you!
We are looking for ArduPilot / ArduPlane experts! We are having some issues with tuning / parameters on a fixed-wing VTOL drone here in West Africa, and we need someone to help us with them! The drone is losing altitude and having pitch/altitude oscillations in fixed-wing flight modes. The drone we are using is a 3.2m wingspan fixed-wing VTOL quadplane with a Cube Orange autopilot and ArduPlane 4.1.1 firmware. Here are the logs of the details of the problem: Logs for Yangda.zip - Google Drive
Contact me directly here if you are interested in this opportunity and can help solve this problem:
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