The Borg can balance

Today we had to make the Borg balance on two wheels like a segway. We used Brian Bagnall´s example as inspiration, but since our robot was constructed differently, we needed to modify the code so that it could balance as well. Since the Borg was taller it meant that we had to speed up more when it was losing balance. We tried our design on different surfaces, like paper, carpet, table etc, and we found that it couldn't quite balance it right, so we tried to change the speed values a bit, but we still couldn't quite make it work. Our design looked like this:






We couldn't get the values quite right, so we tried to change the design to that of Brian Bagnall. His design can be found in chapter 11 of a book called "Maximum Lego NXT: Building Robots with Java Brains".
After we changed the design we found that in order to make it balance, we had to tilt it backwards a little bit. The reason for this is because the we are using the rechargeable battery while Brian was using normal batteries. The rechargeable battery extends out one lego row more then when using normal batteries. This meant that the sensor had to be placed further out then in Brian´s design. It might also be that the rechargeable battery is heavier then normal batteries. We did not check that out.

After intensive tweaking we ended up with a borg that still could not hold its balance completely - although it could wobble for 5 seconds or so before going crazy. In the end it drove off the table and ended up comitting horrible suicide in this manner. It shattered into pieces and we decided to call it a day.