Dumper Vs launcher

So, me and my team mate have been comparing the launcher to the dumper and it seems like the dumper is performing far better than the launcher because of the capacity and time it take to get them over the fence. We’ve also come across a new mechanism we call the claw. Now the claw functions about the same as dumper although it can’t carry as much as the dumper can.

So here are some videos of the dumper

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focus on the red alliance

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and here are some vids of the claw

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don’t forget to leave what you think about these Ideas


In my opinion, the dumper is the superior of the three. It’s scoring cycle time exceeds the catapult. Also with the latest designs, it seems that dumpers are getting close to scoring consistently in the Far Zone, beating the claw.

In second place for me is the catapult (What a shocker!!!). Even though the claw can probably score faster, the claw can’t really get stars into the Far Zone, while most catapults are going to be able to get a star into the Far Zone. Lets say that it takes the claw 4 seconds to score and 2 seconds to restart the cycle, while the catapult would take about 5-6 (I’ll use 5 for this.) seconds to score and 2 seconds as well to restart the cycle. In 2 minutes, the claw can score about 20 times (Not taking into account non-scoring autonomous or pushing) all in the near zone for 20 points, while the catapult can score about 13 times in the far zone for 26 points. In general, the catapult is better than the claw. The only thing the claw can do very easily, in my opinion, is a quick hang ( about 4-5 seconds), but as the season goes on, the robots will be able to do a lot more than just what their generic type of robot specializes in, so I see the claw becoming a lost idea after a month of school starting in the west.

Catapults are getting really close to the speed of dumpers…

While you definitely want stars in the far zone for skills, I think it makes very little difference in matches. In fact, scoring stars right next to the fence might actually be an advantage. Firstly, it obstructs the field for robots that need to drive right up to the fence to score. Secondly, most dumpers will need to do a complete 180 after scoring to pick up stars by the fence. Lastly, stars will pile up and get tangled, making it more difficult for other robots to handle.

Also, the claw has a clear advantage in terms of versatility. They can grab bunches of stars that passive intakes have difficulty with. Combined with the destructive tendencies of catapults, I think for now a claw is the better option.

Agreed, these claws have a big advantage over dumpers,of grabbing the staring from under the fence, where, it is hard for dumpers and catapults to reach.
For the first few scrimmages i had a dump-bot myself, i will be soon changing it to claw.

I definitely agree with what your seeing and as season progress there could possibly a hybrid of some sort that could out-weigh both of them but till then I stand with the dumper being the Ideal bot
thanks for the reply

The biggest problem i have had with dumpers is that they are too big to turn around on field, and hard to get into the tight corners, and it extremely hard to alin the bot while high hanging

I like to think of “claw” as more of “intake type” than a “scoring method type.” What I mean by this is that I imagine (and have seen at a competition) the claw being used as a replacement for a forklift, while the robot still scores in the reverse dumper configuration (ie, intake one way and dump over and behind the robot).

This seems to get the best of both worlds: as others have outlined above, a claw is definitely extremely versatile in its abilities to manipulate game objects; a claw dumper (or potentially even a claw catapult) is also still able to get the benefits of a faster scoring cycle time.

One other thing I would like to bring up is the fact that, IMO, a catapult will slowly become a more advantageous strategy, especially as the cycle times are getting closer and closer to that of a traditional dumper. Why? Primarily, because of the versatility. As robots become more advanced, I think (and have already seen, to some extent) blocking will be a good strategy to help prevent teams from scoring. I am not thinking full-scale wallbots, but rather just a normal 18" wide robot that can block a small section of the fence after driving up to score. When we tested with our dumpapult, however, we found that a simple maneuver could negate all attempts at a block: simply rotate the robot ~45-90 degrees as you release the launch. You could drive up to the fence aiming as if you were launching perfectly perpendicularly to the fence, and then make a last second adjustment that aims to one corner or the other during the ~1 second of launching. This would require the other robot to have a driver with a lightning fast reaction speed, an extremely fast strafing base to reach the new position, and a field cleared of anything that might get in the way of the blocking robot. We think this combination will be hard to attain consistently during matches, which makes the catapult effectively immune to blocking.

A second place the catapult seems more versatile is again based off of the ability to select a launching location. As we get more driver practice, I am hoping that we will be able to get a good enough communication between coach and driver that we would be able to spot and then score in the perfect places to throw “nuisance” stars (like near the Alliance Starting tile before driver load is in play, or hanging corner before an attempt to hang has been made). This kind of positional and range advantage of a catapult, I think, will be the deciding factor as all robots become more and more competitive.

The one issue i have with catapults is movement with objects… i feel if catapults were to truly dominate the game they would have to be able to move around with the objects in any direction… (Hint hint wink wink)…

That’s definitely an issue we experienced at our competition with our dumpapult robot, and in fact we ended up stalling our base a couple times because of all the friction/weight while driving. However, I hope that our ideas for avoiding this will work, which could theoretically eliminate this problem by keeping the objects slightly off of the ground while driving. Then, you would just need to worry a little bit about the weight distribution, but at least the major friction problem would be avoided.

The best intake I’ve seen so far has definitely been the claw. Getting the stars by the fence is a big advantage over catapult/dumper trays. That’s the main advantage against dumpers, because I think there are way to get both to the far zone.

Catapults are another story. I don’t about the rest of you, but we had problems with our catapults and slip gear shooters last year. The amount of force required put crazy stress on the whole system, and these objects are much heavier this year. I think catapults will require to much maintenance. I also think 3-4 stars from near zone to far zone is better than 1-2 stars from far zone to far zone. At first I believed catapults were the only way to go, that all other designs were useless, but now I think the costs outweigh the benefits.

I, respectfully, disagree. Your description of catapults is solely of what they are now, at this point in the season. You need to take in to account what they can be. I believe that catapults are able to get 3 stars from far zone to far zone. Its difficult to fit more than 3 stars on an intake and have it reliably fire. After that, its all about how efficiently you can reset the catapult. I also believe that its possible to have an “instant” reset of the catapult, something that would otherwise be impossible with a dumper. Dumpers take too long to drive to the fence and raise and dump. Not to mention the fact that, as we saw from the SingVex finals videos, there will be many instances of the other team blocking out a dumper, while on the other hand, a good enough catapult can’t be blocked. As to the issue of manipulating game objects around the field (moving around stars and cubes), we’ve actually designed our catapult with “1 way prongs” at the ends of the prongs of the intake so that it keeps the objects on the platform once they’re on. The issue with them is that when you launch, they sort of hook the objects and fire them downwards. It depends on what prongs you use though, and I believe that they can be perfected so the hooking motion doesn’t happen. I don’t know, the idea might be really useful for a dumper bot, though. So conceptually, a catapult will be much better than a dumper once they are developed enough.

As for the structural feasibility of a catapult, sure, a dumper is much easier to build than a catapult, but a catapult isn’t impossible. Your adventures with a catapult last year may have been unfortunate for you, but a simple redesign can sometimes be all it needs. :smiley: A catapult last year didn’t need much force to launch a ball really, but this year, I agree, they take A LOT of rubber bands.

I don’t really like the idea of a hybrid bot. I’m sorry @meng. I just kinda think its an inefficient use of motors and space.

I think that the claw is a waste of time… it is easily blocked and can almost never get an object to the far zone… it may be fast but it will get beat out by the developed dumpers and catapults.

I am now imagining the 2017 Worlds finals, where the winning shot from a catapult gets caught by a raising dumper by accident and adds to the robot’s dump. My point is that nothing is impossible. If catapults are going to be made in such a way that they can’t be blocked, then people will just build a way to block them.

Thank you for the response. Let me clarify. Last year my old team went with a slip gear shooter as our final design and it worked very well. (We qualified for worlds. We didn’t go, but we qualified.) The biggest problem with it was it would put a lot of stress on the robot and we would have to fix it over and over. That’s mostly what I’m scared of. I afraid that so much time will be spent on fixing catapults and not enough time on innovation.

As far as catapult efficiency, by all means, prove me wrong. I’d love to see a three star catapult. I just don’t right now. Maybe catapults are the way of the future, maybe not. It’s to early to tell now.


As i have seen, even if the stars do go in the far zone, the bots will push them user the fence, and they will get clumped together near the fence.

i think that i claw would be really good for this season, if you modify it a bit, and some kind of “pusher”, that push the stars at the same time when the claw releases the stars, you could use three pistons, with pneumatics, two on each side of the claw, and one below it.

as for blocking, make a eight bar instead of 6 , there re not many dumpers that can reach that height.

What about the popular last second Far-Zone score strategy? With the claw, you can’t gain as many points as you would’ve if you were a claw. You could add pneumatics to the claw, but you would make it harder for yourself if you wanted to hang, due to weight (However, if you don’t care about hanging, then go on ahead).

yeah but this robot wont perform as fast or perform so well under competition pressure in theory. Although I could be wrong I stand to my opinion till I see them under the competition pressure

I noticed some previous posters referred to a 3-star far zone to far zone catapult as if it were mythical… It’s not. Our robot from our last competition was able to launch 3 stars this distance, such that at least 2 of the stars landed really close to the field perimeter on the opposite side of the field (the other kinda falls wherever, usually far zone but sometimes near). This also makes it difficult for the opponents to push them forward, because they don’t have the space to “get behind” the objects.

As for the claw: Maybe there’s a misunderstanding of what kind of “claw” we’re talking about, but 7700R Rolling Robots had an extremely successful clawbot capable of dumping 4 stars into the far zone, and they ended up winning the whole competition, too.

Finally, I agree that “instant” reset is possible, but it depends on exactly how “instant” we’re talking about :stuck_out_tongue: Our dumpapult never has to wait for the catapult to wind up prior to a launch, because we are able to wind up with the intake still in position to grab stars and cubes. Additionally, one of our goals is to conduct extensive testing of various configurations of motor gearing, rubber band attachment point (think levers), and sheer number of rubber bands to find the “sweet spot” that balances speed and power. I can’t think of a mechanism that is truly “instant” and able to launch and reset completely in, say, < 1 second, but I am eagerly waiting for anybody whose robot can!