Mid-season Catapulteering

Hi Forum,

Just a quick question, how many of you guys are still with a catapult design? I am, but obviously it seems like claw-boteering is much more prevelant at this time. Also, I like making up words so I hope y’all don’t mind the thread title :smiley:

We’ve been screwing around with our catapult for probably more time than was wise. We’ve basically decided to leave it once we’ve finished the final touches and go clawboteering instead.

We had a slipgear and recently redesigned into a claw. It was certainly the most fun robot to watch and could launch a cube from mid field to far zone but sadly not nearly as effective as a well made clawbot. It was also rather unreliable and the stored energy needed to launch objects was rather dangerous.

We use a double choo-choo to set back and release our arm. It works amazingly well in normal conditions, but whenever we change things a little bit, it suddenly decides it doesn’t want to stay in one piece and breaks something (we just twisted and snapped our fourth axle).

All of the catapulting robots in BC have moved away from them because their rate of scoring is just too low.
They were successful at the beginning of the season because no one had perfected far zone scoring claws.
Now, they just can’t score the volume of object that other methods can.

My team went Claw-boteering and is was definitely a good idea.

Very few teams in the Indiana area have been using catapults. We tested a few designs at the beginning of the season but we decided that out backwards facing claw was a better idea for ease of driving and skills.

It was our first choice but twisted axles and the powerful shake, rattle and roll of the stored energy release quickly moved us past it in September.

with our bot we started to do the catapult but our problem was when we scooped it up we always overshot it and so we decided to go with a claw bot which made it alot easier but at the same time was making the autonomous a little harder. And also with our new clawbot we can score (if we try) in the far zone with a cube.

Ok, TBH these is exactly the responses I was expecting. Now the other question that I have is don’t you think that having the same design as literally everybody else make you worried? How are you supposed to be better than them?

:\ I’d love to have a better design than everyone else, but then it would get copied and then we’d end up with the same problem of everyone having the same design again.
Everyone wants to win.
That’s just the way that design convergence works.

Of the two teams where I am the primary mentor, one has gone with a pretty standard clawbot and the other a complex and unique catapult. Both are very happy with their choices so far, as it meets their goals.

The clawbot does not stand out at competitions and requires strong driving skills to make it perform competitively. That team is focused on winning tournaments as their primary objective.

The catapult is unlike anything else we have seen so far. It has adjustable tension, adjustable release angle, and can reload in < 3 seconds. Since it can fire far zone to far zone with cubes or 4 or less stars, it takes a lot less driver skill to maneuver (you don’t have to race back and forth to the fence for every shot). In addition to trying to do well in competition and skills, the team always has a goal of excellence or design awards, so the sophisticated design helps with this. This same team qualified for worlds last year with a unique turret design which won the design award at the state level, and went on to win the Innovate and Create (Arts division) at Worlds, so they are sticking with that strategy.

This is a long way to say that I think catapults can be very competitive (for scoring and judged awards), and are more interesting than most claws, but they take a lot more work.

I’m just thinking that there HAS to be something better than claws, and I really really want it to be a catapult.

That’s great! I’d love to see it!

I understand if you don’t want to give out more information, but I was wondering, does your team’s catapult has claws for pushing scoring objects onto the platform? By platform I mean the thing that accelerates them and causes them to fly through the air.

@Brian_9605A I am happy to answer any questions, and will post pictures in the next week or so when I get a chance. Over the last year and half since we got started with Vex, we have gotten so much value and learned so much from everyone here on the forum, I think it is important to give back.

As for the catapult, yes it has “claws” to help collect objects. While there are a couple ways I have seen teams intaking onto launch platforms and then move with the items into a firing position (side rollers, partial lift, etc.), arms seemed like the best fit for our situation. They are primarily designed to pull items away from the fence or dig out of corners, rather than pushing them around or collecting more broadly.

Other general highlights:
4 motor x-drive
4 motor tensioner (~20 rubber bands)
1 motor winch (used for arm pull back and stop angle setting)
1 motor claws
pneumatics for catapult release, ratchet release (x2), and initial unfold

Thanks for the info. I’m excited to see pictures.

Our original design was a choo choo launcher for the stars with a fork for loading. It didn’t work too well so we just took out the launcher and upgraded our lifts to 3 motors per tower. So now we have a dumpbot that used to have a choo choo launcher.

Ok, this is a little late coming but here are a few photos of the catapult. The team had it finally working reasonably this past weekend, but still has a lot of tuning to do.

Folded up

Ready to Fire

After firing

Looks kinda similar to 5327c’s robot.

5327c had a great looking catapult, but I think they have moved away from it. This one has some similarities in that it also has claws and rope to set the stop angle, but the implementation is a bit different.

Here is a quick clip of it firing a star corner to corner