Fallout and Repulsion (Antweights)

 Because the Robodojo events have an antweight competition along with the beetleweights, we decided to make a couple of ants to take to the next event. These follow the same theme and colours as Exposure, but are a little less competitive and more of a chance to try new things and make robots that are fun to fight. 

However, I still wanted to make a spinner. So I thought for a long time about how I could make a spinner that would be entertaining, but not too serious, and I eventually settled on a 4WD large undercutter design. The plan was to make the chassis as small as possible but make the weapon as LARGE as possible. The actual chassis footprint is only about 80 x 65mm! This was printed in PLA+ with 2 walls and 30% infill, which feels nice and strong. It also runs on 3S LiPo because why not, and uses a 2700KV 1806 motor to power the weapon. This gives a theoretical tip speed of 319mph, or 34,000 rpm with the largest weapon. Also, due to the battery voltage, we couldn't use the typical BBB 6V N10/N20 motors, instead we purchased 2000rpm 12V N20s from China, and in testing they seem to be quite good! They give a nice bit of speed but are still kind of controllable. One of the biggest issues with this robot were the wheels. I just couldn't figure out how to make wheels that were really light but still had decent grip. This problem was solved by gear- shaped TPU wheels, with the rear wheels running on an M3 bolt and the front wheel connected directly to the motor shaft. This robot was intended to be 4WD using pulleys, however the O-rings kept breaking and we decided it drove well enough with 2WD. The front wheels are 2mm larger in diameter than the back, this was done so the robot can drive upside down but hopefully still be able to attack. The first event for both of the ants will be Robodojo on 27th July.

My Dad wanted to make an antweight robot using a servo. We quickly decided a lifter would be an ideal robot type, so we went shopping online at BBB for a servo and a pair of N10 motors for drive. We had heard from others that the Malenki has the option to reverse driving control when the robot is upside down, so we bought one. It also makes the wiring much easier as we wouldn't need a separate receiver, BEC and drive ESC's. The chassis is black PLA+ with 2 walls and 30% infill with green TPU forks, wheels and covers, finished off with a pair of googly eyes! With a pair of green TPU wheels from my ant, the robot is really quick to turn and will hopefully be able to pin of lift its opponent. The lifting mechanism was the most complicated part - it needed enough strength and movement to lift (or throw!) its opponent, while being strong and reliable. The main forks are made from hardox with some flexible TPU arms above to help it grab another robot. We were really pleased that the lifter arms mean the robot can turn itself back over if it gets flipped.

Testing videos:

RoboDojo 30/07/24

Fallout

Fallout was a little disappointing to be honest. The wheels, which had performed completely fine in our test box, had no grip with the weapon active, meaning I got pitted instantly in the first three fights. In the final fight, we added some double-sided tape to the front wheels, which helped a lot. 

The first fight was against Flik. I don't have a video of this, but I spun up too quickly and bounced around and was lightly pushed into the pit.

The second fight was against Megaflip. This was almost the same as the first fight.

The third fight was against Ash No.1. Same again.

And the final fight was against Olympus, a really cool three part cluster bot. I managed to slam one of them into the wall and then into the pit, but slipped down the pit myself when I took out the second one.

Overall there are lots of improvements needed, but considering we're taking a break from events until September, there's plenty of time to make those changes.

Repulsion

The first ever competitive fight for Repulsion. After an initial flip and recovery, Dad managed to flip Megaflip a few times but it was able to recover with ease. The fight ended with Megaflip accidentally driving into the pit. 

This didn't go so well. The first engagement damaged Repulsion's weapon on one side. Dad tried to line up correctly to flip Relativity but it got some good hits and broke Repulsion's forks pretty quickly.  Dad tapped out and took Repulsion back to the bench for some much needed repairs. Fortunately we brought spares! 

Beat Ya! didn't make it to the arena for Dad's third fight. Fortunately the repairs after the last fight worked and Repulsion was able to show mobility. 

By the forth fight Dad was beginning to drive Repulsion better. He managed to chase Piece De Resistance around the arena and flip it a few times, including a winning flip into the pit.

Then my dad got a place in the 6th place rumble. His strategy was to stay away from others during the initial charge, but he quickly ended up on the receiving end of Dissector's overhead saw. He managed to free Replusion without too much damage then tried to go on the attack. After a failed attempt to flip, he was quickly pushed into the pit by Expandabot who went on to win the rumble and finish in 6th place overall.