: Premature Motor Cut at 1.5m and Severe Roll Oscillation During Landing

PX4 Autopilot
1

Hi everyone,

I am experiencing a critical landing issue with a fixed-wing UAV. Here is our setup and the exact sequence of events.

Setup:

  • Flight Controller: Pixhawk 2.4.8 with M8N GPS

  • Firmware: PX4 (Latest Version)

  • GCS: QGroundControl (QGC)

Sequence of Events:

  1. The aircraft was flying autonomously.

  2. We experienced an RC signal loss mid-flight, and the drone correctly switched to Hold mode.

  3. Via QGC, we reloaded the landing route and commanded the drone to continue.

  4. The aircraft successfully entered the landing pattern.

  5. During the final approach, the aircraft suddenly started rolling aggressively left and right (severe oscillation).

  6. At exactly 1.5 meters above the ground, it completely cut power to the motors before actual touchdown.

In a previous flight with this exact same airframe and without changing any parameters, it landed perfectly and cut the motors only upon actual ground contact.

Has anyone experienced this premature motor cut and roll oscillation, especially after recovering from an RC loss? Could this be a sensor/EKF issue tricking the land detector?

  1. :red_circle: Failed Flight Log (Premature cut & oscillation): [Flight Review]
  2. :green_circle: Successful Flight Log (Exact same setup & parameters): [Flight Review]

Thanks for your help!