This robot has to hang from a cable and, using a reaction wheel, actuate towards an infra-red target. The robot must fire a laser for 2 seconds at the target, which is comprised of 3 different accuracies/points. The robot has 2 minutes to score as many points possible and a grade awarded accordingly. This was my 1st robotics project at the University of Queensland last semster.

This is the ’tube link to our robot in action and a montage of the night before submission:

http://www.youtube.com/watch?v=Ns6xdK3QVoI

Ours is the one at 0:29, 0:34, 1:00 – 1:37. I haven’t got any photos of it, we had to hand them in to get dismantled and thrown out. But I have included the final cad design image, top side view of the reaction wheel. We named the satellite Daedalus after the Ancient Greek artificer who built the labyrinth to contain the minotaur.

The wheel ended up weighing about 1.2 kg, which had the same moment of inertia as the satellite. The motor had a gearing ratio of about 45 as well. I designed the satellite to be simple mechanically, we had buckets of space left over. Every one was given the same ‘can’ for the case and the same motors. We had trouble with torque in the cable, so we put a skateboard wheel type device under the bracket and strung the satellite up with that. It worked ok, but we still had trouble with the cable winding up. The satellite ran on 8 AAA batteries and we managed to fit the reaction wheel, platform (which held everything in place except the pcb) and batteries to fit in about 4 inches. The pcb attached to the bottom lid as did the laser.

We did ok, we came 4th out of 11 with a score of 53, which we were quite happy with as the groups were ordered by grade point average. If only I had more time on PID tuning!