Oscillations after Take-Off then Rapid Descent to Ground

Flight Testing & Log Analysis v1.14
1

First post,

I built a Tarot 960 hexacopter and I have flown it without issue when flying the frame and battery (even though the battery makes the frame unbalanced); however when I mount a payload (balanced), I get weird oscillations in Position mode after Take-Off and causes the drone to descend rapidly. In the flight log below, I manually increased the thrust to 100% during the descent but it did not appear to change anything. Can anyone provide any insight to identify what might be causing this? I greatly appreciate any and all help.

I managed to find another post that mentions MPC_THR_HOVER and PID tuning. My MPC_THR_HOVER is set to 50%. I have not yet run Autotune due to not being confident in Position mode.

My setup is as follows:

  • Frame: Tarot 960mm Hexacopter
  • Motor: T-motor U7v2 280kv w/ T-motor 18.2x5.9 Props
  • ESC: RDQ 32bit 30A (DShot)
  • FC: CubePilot Orange+
  • Radio/Telemetry: RFD 900x
  • GPS: ARK RTK GPS
  • Battery: 6s 22000mah
  • Gimbal: Gremsy T3V3 w/ Sony A7Riv

Flight Log: PX4.io flight log

2

Hi
Kindly do the autotune in Altitude mode and not in position mode and then post results here

3

Your vibration metrics are off the charts. How is your cube mounted? Are there loose parts or landing gear?