Elastic Shooter

I’ve been searching for a robot that can shoot balls using elastic force (such as that of a spring) and have found very little results. Does anyone have any resources/examples of robots that use a spring to launch balls?

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Check out robots from 2014 or 2016. 2014 saw a lot of teams winch a spring back then release it to shoot the yoga ball. In 2016 since there was a one ball limit some teams used a pneumatic catapult to shoot the boulder.


You should check out 330’s 2016 robot (although i think that was a pneumatic punch)

Pneumatic punch confirmed.

Generally speaking, most teams don’t use springs to launch balls. 2010 and 2014 tend to be the primary examples for when teams did. Key takeaways: Surgical tubing isn’t reliable enough without regular maintenance/replacement, get something better.


And 08, but there’s not much from that cuz apparently it was a ‘long time ago’ and ‘ok boomer’ :frowning:


Thanks for the suggestion! I was able to find way more resources for inspiration.

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Hey! A specific example could actually be team 1519 from 2016. We used a combination of constant force springs and surgical tubing inside of a linear track on our arm. It worked! It added a lot of complexity to the design, but we loved the consistency of the shot.

Some images and links to 2016 videos below. :slight_smile: Happy trails.


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There’s cit in half surgical tubing in there for the retract (“exhaust” ports were left without fittings) but linear pneumatic launching. Might be a decent candidate for low goal this year.

Love this! Do you think elastic force like this would be enough power to get this year’s cargo all the way to the top port since it’s a larger ball?

The short answer is yes, the long answer is I’d be careful! It was pretty difficult to maintain the shooter with the constant force springs and surgical tubing and we designed it for the amount of force that was being put through the arm. You could foresee a shooter with basically more elastic tubing for more force or more constant force springs (we also used constant force springs on our 2014 robot) that could launch the balls further, but a lot of the questions about how to actually launch something like this year’s ball the proper distance would have to be answered through your own prototyping. That said, In 2016 there was only one ball, while this year’s game you can hold two at once, and the linear shooter wasn’t the kind of shooter we could preload multiple times in quick succession. Just some things to consider!

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3946 had an elastic (about 18 steel springs) catapult style shooter for STRONGHOLD. It was drawn back and locked in place with pneumatics; it was pretty simple. We used Versaframe or similar holes to mount the springs. We used rather small springs so we could tune the shooter by adding or removing a couple of springs. If I recall correctly, the springs were about 1/3 stretched at the launch end and very nearly at the rating length when cocked.

118 from frc stronghold

1678 from 2014

118 from 2014

That was a pretty sophisticated catapult using two pneumatic cylinders. They had a way of adjusting the strength of the shot to account for the distance.

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