Several lessons were identified here  from the entry of The Groundhog hexacopter in the MAAXX Europe competition earlier this year.

Current developments are around correcting the issues so that we get a UAV successfully lapping the oval track at a minimum average speed of 1m/s.

A number of changes in approach have been made from that previously blogged.  Recall the platform is based on a combination of Pixhawk/Raspberry Pi3/OpenCV/Dronekit.

Image analysis:

  1. The birds eye view image transformation in OpenCV was causing segmentation faults on the RPi.  Instead the position and bearing of the detected line is calculated using straight trigonometry.
  2. Improvements made to the ranging ROI bands to further speed-up the frame rate.  This is now at a reported 50fps (which is faster than the PiCam is supplying them).

Control algorithms:

  1. The use of quaternions has been temporarily suspended in favour of control by velocity vectors.

As in MAAXX Europe, it makes sense to initially test on a straight line.  Initial testing was conducted outdoors using red-seatbelt webbing for the line.  It was not possible to fly below about 2m as the propwash blew the line away (will sort that next time!).

Initial Testing (Links to YouTube Video).

Video – Groundhog UAV initial testing on straight line.