Drone Oscillation Issues in Loiter and PosHold Modes with F9P GPS

Hi everyone,

I’m experiencing some stability issues with my drone and would appreciate some guidance. Here are the details of my setup and the problem:

log fileSetup:

Flight Controller**: Custom-built with STM32F427 Cortex M4 core
GPS Module**: F9P Rover Lite
IMU Sensors**: ST Micro L3GD20H gyroscope, ST Micro X4HBA 303H accelerometer/magnetometer, Invensense MPU 6000 accelerometer/gyroscope, MEAS MS5607 barometer
Additional Hardware**: Gripper on the front side, shifting the center of gravity 10 cm forward


In Altitude Mode, the drone flies stable with no oscillations.
When switching to Loiter*or PosHold modes, the drone starts oscillating and becomes unstable Troubleshooting Steps Taken:

  1. GPS Accuracy: Checked HDOP values and satellite count. HDOP is consistently below 1.5 with more than 8 satellites tracked.
  2. Magnetometer Calibration: Performed multiple compass calibrations to ensure accurate heading information.
  3. PID Tuning: Adjusted the PID gains for loiter and position hold modes, but the oscillations persist.
  4. Vibration Check: Ensured all propellers and motors are balanced, and the flight controller is isolated from vibrations.

Despite these efforts, the oscillations in loiter and position hold modes remain. I’m seeking advice on further troubleshooting steps or adjustments I might have overlooked.

Any insights or suggestions would be greatly appreciated!

Thanks in advance for your help.

It’s to be expected on default parameters. Go here and get to work: The Configurator

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