Is a dump bot a good idea?

4043c · May 9, 2016, 6:04pm

Our team is thinking of a dump bot which picks up stars three at a time, then just dump it over the fence into the low zone(maybe few could bounce into the high zone)

Game object manipulator and the hanging hook is mounted on a six or eight bars lift

Out team is having a debate on “catapult or dumper” considering is there is quite a few strategies is aviable this season. Just want to hear the opinion of the vex forum.

novaabhi · May 9, 2016, 6:07pm

We are going with a catapult, but it seems as if dumper is the way to go, if you could fit a bunch of stars. Though dumpers might not go as far, the stars launched by a catapult are going to be pushed into the near zone anyways. Dumpers are a great way to overwhelm your opponent, but unfortunately are slow, and useless against wallbots.

Bobtheblob_5327B · May 9, 2016, 6:21pm

Why not a dumpapult? High capacity catapult that launches from anywhere on the field?

Until we get into the competition season and start seeing robots at various points along the launching capacity/frequency curve, I think it will take a lot of prototyping to see if you can cram another star on without significantly affecting shooting speed.

roboticblackbelt · May 10, 2016, 7:05am

I agree they are a great way to overwhelm your opponents, but I think that a dump bot could easily score as fast as a catapult if not faster, and if the lift is high enough it will be able to dump over wallbots.

7368W · May 10, 2016, 7:21am

Our team is mostly likely going to use a dumper. If your lift can reach about a foot over the fence, a good number of the stars will be able to bounce to the far zone, a tall enough lift or fast enough straffing should be able to overwhelm wallbots

n5vei · May 10, 2016, 7:35am

I believe you will see lots of dump-bots in the beginning as well as walls. BUT… I think that the wall-bots will be outdated quickly with clever lifts.

OverlyOptimisticProg · May 10, 2016, 8:12am

I doubt we will have to worry about wallbots… I also doubt that a dumping robot can keep up with a catapult robot… The good thing about a dumping not is dumping a large number of stars in the last couple of seconds so they’re pretty balanced…

4361T · May 10, 2016, 9:52am

Wallbots = forever dead in VEX

Team80_Giraffes · May 10, 2016, 12:00pm

And the rebirth as a volleyball net bot!!! (more like a badminton net bot as it is only 2 feet off the ground)

Expand and unroll a net to block the stars from coming over. In that way a lot more like volleyball. Replace the people and arms with robots…

http://volleyball.isport.com/userfiles/Guide/image/Volleyball/Volleyball-Block-Attempt.jpg

anon50541363 · May 10, 2016, 1:19pm

How do you plan on holding three stars?

7368W · May 10, 2016, 1:27pm

Two prongs like for a forklift that are 15 inches long will easily fit three stars between them. Much shorter and the third star could fall off too soon

Papa_Nol3510 · May 10, 2016, 1:59pm

How are you planning to pick up the stars into your forklift without the help of the fence or a wall? Also, once you get the stars onto the forklift, how would you make sure the stars wouldn’t fall of your forklift as you move them higher?

SamuelC_7842D · May 10, 2016, 2:14pm

To pick up the stars with a forklift, just push the prongs between the stars’ legs.
As for keeping them on, a mechanism that flips the platform behind would be useful.

4043c · May 10, 2016, 5:06pm

I’m planing to have three forks that deploys passively, when deployed should be somewhere around thirty inches.

4043c · May 10, 2016, 5:09pm

I’ll have the forks on a rotating wheel of some sort, once we grab a star, tilt the whole thing up, so nothing falls off.
When lifted over the fence, just tilt down and then let gravity do its work…

OverlyOptimisticProg · May 10, 2016, 5:19pm

Lego technic ftw!

Infinity Minus 1:

Let’s break down the catapult design first, and then we can look at the dump-bot design. OK, so the name of the game is cycle time. If you can collect and dump/shoot stars over the fence at higher rate than your opponent, you will win. It’s that simple. A catapult bot that can pull the catapult back in 1.5 seconds, collect a star in 1 second, and launch in a half a second will have a cycle time of 3 seconds and will score slightly greater than three, and sometimes closer to 4 (depending on the opponent’s ability to score into the catapult-bot’s far zone) points per shot. Actually they are descoring 1-2 of the opponent’s points and scoring 2 of their own, but you get the idea. At a bare minimum, they are scoring an average of 1 point per second.

Now let’s look at the cycle time of a dump-bot. The dump bot discussed here would be able to hold 3 cubes, so let’s say it takes 1 second to intake. Assuming 1 second to lift and another second to lower the lift after the previous dump, we are now up to 5 seconds. Then the robot has to drive from wherever they are on the field to the wall, which might take another second. That’s 7 seconds. However, bear in mind that they are scoring many fewer points per dump since they can only dump into the near zone. According to excessive testing I’ve done (I literally dropped the star from registration off of my roof 16 feet in the air), stars bounce no more than 14" when going at a high speed, and certainly no more than a few inches when going at the low speed they would likely be going when dumped from a dump-bot. This means the dump bot would be scoring a minimum of 6 points in 7 seconds, which is slightly less than the catapult bot.

Now let’s look at how each design fares against better or worse opponents. The fact is, the dump-bot scores better when the opponent is only depositing stars in the near zone, while the catapult-bot scores just fine when the opponents score in the far zone (again, assuming it can shoot from anywhere). In all likelihood, the finals of competitions will be between robots that can propel stars into the far zone. Thus, the catapult bot not only has a slightly higher cycle time, but fares better against stronger opponents, meaning IMO it is a better choice.

It’s no question that a dumping robot can’t keep up with a launcher robot mid or early game but the end game of the dumping robot is super strong… A popular strategy would probably be to try to keep up with the enemy catapult bot middle and early game and then overwhelming them late game with a last second dump… I personally think that that end game is what balances out the 2 strategies as the only points that matter are the points at the end. What I really want to do(and I’ll probably never get to do) is make robots with 1-8 star storage (8 different robots) and graph the points on the enemies side at the end of the match when facing one or two robots… Maybe one will be overwhelmingly stronger or a combination

novaabhi · May 10, 2016, 5:46pm

If you want to hold that extra weight of stars, (comparing one star to 4-6 stars), you are going to need a torque- geared drive. That is going to make navigating your side of the field to get to the stars, as well as getting to the wall slower. Not to mention, catapults are able to launch from any position on the field, so you don’t need to intake the stars, then travel to the wall, you can make your intake and launcher synonymous.

roboticblackbelt · May 10, 2016, 6:36pm

@novaabhi You don’t think an 8 motor drive will be fast enough? You can intake a lot of stars then dump them all at once at the end of the match to overwhelm catapult bots.

novaabhi · May 10, 2016, 6:50pm

Maybe, but compared to a, eight motor drive with a 2 motor catapult, launching only one star, it may not be as fast. To be honest, I agree that dumping bots may be more beneficial, but variance is good. If every team builds a dumpbot, it may not be a bad idea to go with a catapult.

SamuelC_7842D · May 10, 2016, 6:57pm

I think that it’s too early to know what strategy will come out on top, but I agree with @novaabhi that variance will be beneficial.