Bison Robotics Ri3D 2020 - Robot Reveal

Hello Everyone,

I am from the Bison Robotics Ri3D team from North Dakota State University. We just finished editing our reveal video and a full walk through will be coming in the next few days. Feel free to ask any questions and we will get back to you asap. We had a lot of fun and hope you like the robot as much as we do.

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This is an awesome Ri3D build, very impressive! Will you have a CAD files available for parts of the robot? Also what was your accuracy like shooting from where the Trench Run would be?

We will not have CAD available. Our accuracy from the trench run in the 2pt hole was high as long as the shooter could get back up to speed. I do not know a specific number.

OK thank you

This robot demonstrates just how forgiving the outer goal is. A fixed hood flywheel can score from so many places! Was the initiation line the closest you could get at that angle?

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Yea the initiation line was the closest. We wanted to have an adjustable shooter hood but didn’t have time.

What are you using on the shooter? Is that a falcon 1:1 to the 4" wheels?

The shooter is a 775 pro with a 1.33:1 gear ratio. The wheels are 4-7/8 in colson performa wheels.

What compression are you running?

I don’t know the specific amount but it was around 2in of compression.

The indexing mechanism on your robot is the best I have seen. Did you have any trouble with balls slipping or sticking together? Also were you using sensors to index?

What wheels are you using for the middle of the intake?

Thanks. We had a lot of problems with ball sticking which led us to the indexing mechanism. The indexer was designed to use sensors to provide even spacing of the balls but we ran out of time to program that functionality. We could manually index if we could see the balls but on the other side of the field an automatic indexer would have been necessary.

The middle wheels are hubs wrapped with blue nitrile tread. The read was not an ideal solution but was what we had on hand. The middle most wheel was double wrapped because we needed a larger diameter but had no other larger diameter wheels.

What is the approx angle of the hood?

I don’t know for sure but probably about 30deg. I don’t think this is the ideal angle but we were hitting the ceiling any higher.

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Awesome job guys! do you have any videos on the intake moving the balls on the mecanums? The reveal video doesn’t really show it. Also I noticed that you’re missing some mecanum rollers on one of the wheels.

How long does it take for the flywheel to regain speed after a shot? And why use 775 motors over the NEOS that other teams seem to be using?

Thanks! There is some video of the intake from an earlier version but it acted the same in the final version https://youtu.be/FrQAf4ZvXmE?t=111. I don’t think we have any other good video of it unfortunately. The rollers were broken through some head on collisions with the wall but didn’t impact functionality all that much.

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The flywheel took about 3 seconds to get back up to speed. We used a 775 because of the higher RPM without gearing it up and because we had them available.