Exodus One was the first robot produced by a Queensland team to enter the Australian Regionals for the FIRST Robotics Competition. The game this year was medieval themed and featured a tower at each end and obstacles in between. To score points, robots needed to pass through obstacles as well as shoot soccer sized balls (referred to as boulders) into goals in the opposing team's tower. Competing in this game was very difficult as the robot would mostly spend time on the side of the field furthest away from the driver which meant vision was very low adding greatly to the challenge.
The low goal was slightly elevated but had an incline that robots could climb if they wished to be level with the goal. The high goal, however, was over 2m in the air which was well above the legal height for a robot so a shooting mechanism must be used to score in this goal. Exodus incorporated a shooting mechanism which was based on a fly wheel which would spin at a very high velocity and have a ball fed into it. The feeder we used for this was rather unique, it consisted of a pronged arm that was actuated by scissor jack driven by a motor. We used our first ever 3D printed parts to make a coupling from the motor to the jack which can be seen in the picture below.
To collect the ball, the jack would be lowered so the ball could be collected in the prongs. The prongs were then raised to 'scoop up' the ball and store it while travelling. When the robot had lined up its shot, the wheel were spun at full speed (approx. 4000rpm) and the jack was raised until the ball was grabbed by the wheels and thrown out. Unfortunately, the wheel selected for the flywheel were not meant to spin as such high velocity and began to stretch during testing. By the time the robot had made it to the playing field, the rubber would stretch so much that it would affect the performance of the mechanism. Because of this, Exodus did not end up scoring any high goals at the competition.
The tower also features a steel bar just under the low goal that robots can latch on to and use to climb up the tower. If a robot could do this successfully, they would score a large amount of points. At the Australian regionals, no teams completed this challenge although some came very close.
During the competition, the obstacles are where we were able to score the most points. Although Exodus only used the base from the kit of parts, it proves to be quite effective at climbing over and navigating the obstacles due to its lightweight design. In each game there are 5 obstacles on each side of the field, 4 of these may change but the low bar was in every game. The table below shows which obstacles could be in certain positions. It was decided early on that Exodus would be designed to complete the low bar as this was in every game and would be an easy obstacle. As well as the low bar, Exodus completed most other obstacles consisting of: the ramparts, drawbridge, sally port, rock wall, moat and rough terrain. In order to get over some obstacles, a program was made that would make Exodus do a wheelie so it could mount and sometimes clear the obstacles using momentum built up before actually engaging with the obstacle.