With day four of the competition came the obstacle avoidance challenge. The Black Python first needed to sail back and forth inside a 150 m by 20 m rectangular area, after which three orange balloons would be towed in the course as obstacle. The challenge is to recognize and avoid those obstacles.
Our strategy in obstacle avoidance is very simple: a set of way points are set along the direction inside the rectangular area. If no obstacle is found, the Black Python will sail straight ahead to the next way point. When the obstacle is detected by the on board camera, our boat will try to sail towards an alternative way point perpendicular to the main course.
Preparation before the mission
The obstacle avoidance program reads images from the webcam continuously. It counts how many pixels in a image match the colour range of orange balloons – the obstacle. If the percentage of obstacle pixels is large enough it then regard as an detection of obstacle.
Sounds good? But the unexpectedly peaceful weather on Thursday brought the wind speed down a lot, and the changing wind direction made it very hard just to sail along the course. It took ages for the Black Python to even reach the start line. After the first trial, we changed sails from the smallest set to the middle one, but the wind completely died out as we were trying to get through the start line. Besides this, there was some compass issue that stopped us from making further trials today. But we could reliably detect those obstacles in tests on land, and due to a range of technical problems affecting other teams, we were the only team to make an attempt in this challenge.
After the final challenge, we celebrated with a glass of sparkling wine.
All teams are invited to the prizegiving banquet dinner at Sjømilitære Samfund, which was previously an officers club of the Norwegian Navy. During the dinner, we heard a bit about the history of the beautiful building, of the town of Horten, and how to the competition came to be there. We really appreciate the effort the organisers have put into the year’s competition.
The most exciting part of the dinner comes to prize giving: with three out of four challenges completed in top position, we successfully defended our title in the ‘Micro Sailboat’ class.
The trophy is a beautiful pewter model of a traditional Viking longship.
Southampton Sailing Robot Team would like to thank everyone who supported us in the competition and the preparation. See you next year!