The ROBO-ONE organizing committee always likes to raise the bar just a bit with each succeeding competition. It challenges the builders to keep honing and improving their skills and the performance of their robots. And, at the same time, it keeps the number of competitors that make it into the finals down to a manageable number.
For ROBO-ONE 13, the committee decided to make the pre-screening tests slightly more difficult with the addition of a small slope. To pass the pre-screening tests for previous ROBO-ONE events, the robot typically had to be able to walk for a minimum number of paces, turn around, and show that it could get up by itself from a prone or supine position. Roughly 30% of the entries would fail to pass the pre-screening.
This time around, the robot had to walk straight forward across a surface that had a small slope (think "speed bump") right in the middle. As it turned out, the challenge may have been much more difficult than the committee originally expected.
The pre-screening slope specifications were published on the ROBO-ONE website well in advance of the competition. And, when some of the builders of large robots pointed out that the slope might impact them more than the smaller robots, the committee responded by allowing the large robot builders to use a slope with slightly different, and fairer, dimensions.
Nevertheless, some builders seemed to have a real problem getting their robots to walk across the slope. It was really binary. Those that could handle the slope did it extremely well - to the point that it looked like they weren't bothered by it at all. Others couldn't traverse the slope to save their lives.
Of course maintaining balance was a significant issue. Another problem was that some of the robots tended to turn off to one side or the other as they crossed the crown of the slope. A good example was Metallic Fighter. It was able to successfully cross the slope, but turned so much in the process that it walked off the side edge of the table just a fraction of a second before it crossed the finish line (see photos above and below).
Unfortunately rules are rules, and Metallic Fighter just barely missed qualifying. There was some discussion/debate with the referee, but to no avail. If they had bent the rules to let Metallic Fighter pass, then they would have been forced to do the same thing for several other competitors.
The net result was that fewer robots made it pass the pre-screening test and were able to stage their prepared demonstrations. Although we understand, and support, the reasoning behind holding the line on the pre-screening, it is really a shame that more of the demonstrations will never be publicly seen. Frankly, we usually enjoy the demonstration phase of the competition more than the battles in the ring. It would have been great if the committee had arranged for the non-qualifying demonstrations to be shown during breaks in the action - like during the long break for lunch.
Here's a video showing some of the attempts to pass the pre-screening slope test: