Servo - November 2016

SERVO 11.2016 23

once it started spinning up.

As with all the prior upgrades, the next weak spot made an appearance. This time, it made its way back to the weapon shaft. While it was reasonably well supported and a decently tough material, eventually a big hit or several would either bend the shaft, explode the 3 mm bearing, or cause the shaft to work its way out of position.

This lead to the final design revision: an overhaul of the motor-in-weapon setup after Algos managed a 20-5 record in the V2 arrangement.

Algos Version

2. 5

The two things that had to happen to the weapon were that the shaft had to be actively retained and it had to be strong enough to resist bending even after the nastiest hits. After looking at a few options, I settled on removing the bearings from the stator (the part of the brushless motor with the copper windings) and drilling it out to accommodate a 1/4” shoulder bolt. This also meant that I’d have to move the bearings into the drumette itself.

After finding suitable bearings and taking measurments to determine the correct offset between the new bearings and the old stator, I got all the critical parts ordered including a small pile of steel shims that would allow me to precisely set the spacing and had a fresh drumette machined.

For this arrangement, the stator was mostly left as delivered outside of the removal of the bearings and the enlarged bore. For the rotor, however,

the only part left was the magnets and the metal ring that retains them. This was pressed and glued into the drumette, effectively turning the drumette into the new rotor. At this point, Algos was in its final state. The drive was fast, the weapon was durable and destructive, and the chassis could handle just about anything thrown at it. The final revision of Algos lived up to its potential, winning Motorama 2015, the Freeside Robot Street Fight, Clash of the Bots 2015, and Dragon Con Robot Micro Battles 2015 — all with essentially no maintenance, no issues, and a total of two losses. By this point, the first drumette was looking a bit worn out, so Algos was taken apart for a cleaning and drumette replacement. During the cleaning, it was clear just how hard the current setup is on the stator. However, it also was clear that even with the stator feeling some of the shock, the weapon as a whole was holding together well. With a fresh disk on and Algos reassembled, it was ready for its final run. Algos went undefeated at Robot Battles 57, Robot Battles 58, and Motorama 2016, having a combined 13-0 run across those competitions. With the win at Robot Battles 58, it had also managed to win every event it attended for a full year, and finished with seven straight event wins and an overall record of 32-2. While Algos could fight again as it sits or be fixed up a bit and look as good as new, it’s done everything I wanted it to do and I’ve learned a lot in the process. It’s had an amazing run, and there’s nothing I want to change on it. I think that means it’s time for something new. SV Here’s the magnet ring and drumette prior to being pressed and bonded together along with the shoulder bolt used as the weapon shaft. Algos V2.5 freshly assembled and ready for Motorama 2015.