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-   -   Why was stacking so hard? (http://www.chiefdelphi.com/forums/showthread.php?t=19066)

Joe Ross 11-03-2003 21:10

There are many elements to being a good stacker. My team is still far from a good stacker (although we were closer then any other team at cleveland :p)

1) you must have bins to stack with, so either you or your partner must have a good autonomous mode.

2) you must have some way to get those bins upright, and quickly

3) you must have some way to pick up boxes that are not lined up perfectly with your robot (most internal stackers have this problem)

4) you must be able to accurately place the box on another (most arms have this problem)

5) you must be able to protect your stack for the majority of the match.

6) you must have the traction and driver skill to do all this while being harassed.

There are probably a lot more, too. Our robot is deficient in several of those. The best video that I have seen of our robot stacking in real competition conditions is qf1m2 from soap (10mb) http://www.soap108.com/2003/movies/oh/oh_qf1m2.asf also good to note that we lost that match. In fact we lost most of the matches where we stacked. So just because you can stack doesn't mean that you will do well or seed high.

I will be very interested to see how you guys do at competition.

Josh Hambright 11-03-2003 21:16

stacks dont have to be upright to stack
we stacked one on its side on one upright cuz we rule!!! woo robots

Joe Ross 11-03-2003 21:32

Quote:

Originally posted by oneangrydwarf
stacks dont have to be upright to stack
we stacked one on its side on one upright cuz we rule!!! woo robots

But you didn't stack another on top of the one on it's side (and if you did...I'd really really like to see how).

A stack of two doesn't make you a very good stacker. To make a good stack you must do each of the things I said above at least once.

ngreen 11-03-2003 22:17

if you can quickly make 2-3 stacks of 3-4 boxes you will be successful. This can be done in a little over a minute and can be protected as long as necessary.

You can stack other way than upright and nest.

Personally I prefer upside-down, It is easy enough to do, they nest better and they stay up better than upright stacks.

Josh Hambright 11-03-2003 22:33

well we did do all those things at some point or another...
maybe not protect but we had protecting arms that we can stick on that holds a stack of 4 firmly without any problem.

As far as stacking on top of a side one...i'm not sure but i think we threw one on top of one on its side with another next to it, this is till a stack.

PMGRACER 11-03-2003 22:39

GLR may prove stackers
 
Some of the teams going to the GLR are notoriously good at dealing with balls/floppies or whatever. GLR may prove that a good stacker may have what it takes to beat the KOTH 'Bots. I can't wait to see how the new HOTBOT deals with bins or how well 857 can grab and protect stacks. We will also have some pretty tough KOTH 'Bots, Truck Town as well as Wildstang. This regional will be exciting to say the least!! And those are only the teams I can think of off the top of my head. As was proven in Clevland, there are a lot of strong 1st, 2nd and 3rd year teams too!! Heck, we couldn't have won without 1126 and 541! What is neat about our alliance was the fact 1126 is in their rookie year, 541 in their 3rd and us, in our 7th year! Don't count out some of the new guys, they will suprise you!!

The Lucas 11-03-2003 22:54

Quote:

Originally posted by robohyo
if you can quickly make 2-3 stacks of 3-4 boxes you will be successful. This can be done in a little over a minute and can be protected as long as necessary.

Why plan to make more than one stack at once. Make one large stack and defend it. It is nearly impossible to defend multiple stacks.

Brian48216 11-03-2003 23:05

not enough time
 
FIRST did a good job designing the game and all but they didn't include enough time for stacking to be of any use at all. It's more a matter of getting boxes on your side, and king of the hill. Stacks are just a bonus.

ngreen 11-03-2003 23:16

As hard as it is to defend multiple stacks, it can be just as time consuming knocking down multiple stacks. By doing in double you keep a step ahead of the other robot. Anyway when you set up to try to defend your single precious stack, you are telling the other team to attack and knock it over. Keep quick and keep moving. It will pay off in the end. Anyway, they are just boxes whether they are scattered on the floor or if they are nicely stacked in columns. Not only will the field look prettier but the people preparing the next round will thank you for your generosity by giving them a several stacks to move onto the ramp instead of a scattered row of a failed attempt to build a monster stack. The boxes only stay stacked well when less than 4-5 and then they are a pushover. But that's just my opinion. I'll guess I'll learn in Houston.

kevinw 12-03-2003 09:31

Quote:

Originally posted by Joe Ross
There are many elements to being a good stacker. My team is still far from a good stacker (although we were closer then any other team at cleveland :p)

Actually, I saw 73 at Cleveland, and would have to say you are not far from a good stacker at all. In fact, stacking would have overcome the KOTH if you had one more bin count in the second quarterfinals match.

EbonySeraphim 12-03-2003 09:49

Why was stacking so hard? Like most people have been saying, there is not enough time to do it. Even team 435 who did stack boxes successfully and defended it, took a considerable amount of time doing so. Though they defended it, I'm sure if they were up against a fast and agile robot(or a good driver), that stack could have easily been destroyed. Stacks do matter, there is no question about that. The problem is making them in the frenzy of a match. Some one else also said that other robots in that time could be doing anything. By taking time out to make a stack, you are leaving your alliance partner out there against two other robots. To blow that situation out of scale - that's like trying to make a tower of cards while 25 toddlers(little kids) run around you in a small room.

I will also say that our team did well (623 - Ohm Boyz - Oakton High School - VCU Regionals) did well without being able to stack anything for crap. We got as far as we did with a great human player, and a controllable robot that could push other robots around and knock over stacks.

In my opinion, making a stacker robot is sort of like trying to get up a hill, but if you dont make it, you will fall off completely and be further away from the top than those who never tried to make it in the first place. I think it would take an incredible amount of engineering experience/creativity/design and planning to make a stacker robot overcome all of the challenges of stacking during a live match.

CaptMatt15 12-03-2003 13:39

I know that our team took lots of time to stack the boxes (we being 435), but what else are you going to do with the time? just run around and then the go for the hill? instead of running around we stacked, and in our last round we had a small, agile robot pushing us and still managed to make a 3 stack from nothing, and we still had time to fight for the ramp (props go out to grundy for that little fight there and for winning the chairman's award!). with a good robot stacking works - you just have to be willing to commit to it.

Mr. Van 12-03-2003 15:34

This game points out a fundamental truth: It is far easier to destroy something than it is to create it.

Stack attackers are working with the second law of thermodynamics on their side while stackers aren't.

One of the problems is that with three rather powerful pairs of motors in the kit (CIM, drill & FP), robots have too much power available for a drive system. Many robots can get from one side of the field to the other in about 5-7 seconds (under the bar - add a couple of seconds to go over the ramp).

In Sacramento our driver left the top of the ramp to go into the opponent's scoring zone, knock over a stack and return to the top of the hill. Total time: less than 10 seconds. (And our robot doesn't shift.)

I'd like to see more stacking, but the speed of attackers simply doesn't make it very practical. My suggestion to FIRST for next year: drop some of the more powerful motors, double the amount of pneumatics.

-Mr. Van
Coach, 599
RoboDox

The Lucas 12-03-2003 17:53

Quote:

Originally posted by robohyo
As hard as it is to defend multiple stacks, it can be just as time consuming knocking down multiple stacks. By doing in double you keep a step ahead of the other robot. Anyway when you set up to try to defend your single precious stack, you are telling the other team to attack and knock it over.
I figure most bots could knock down every undefended stack in scoring zone in less than 10 sec. A bot would have to be incredibly good at stacking to make one stack of 3 in 10 sec.

Internal stackers like 73 have the best chance to defend a stack (#5 on Joe's List) because the stack is supported by their bot while they are stacking, so only one stack needs to be made. They can wait for a safe moment near the end of the match to place the stack.

External stackers will probably have difficulty defending stacks, so maybe constantly making small stacks is the best strategy for them (depends on stacking speed). Since external stackers usally have to leave the stack undefended to find another box, a new stack of 2 might be all that is left at the end of the match.

Overall I think only about 30 bots (mostly internal stackers, sorry external guys) will become consistent stacker by nationals. By consistently stack i mean stack and defend a stack of 3 or more in over half of thier matches. A select few great stackers (maybe not that good at first regional) will be the top seeds b/c thier qp potential is so high. Imagine just letting ur opponent have the 50pts on the hill b/c u have 70pts on the floor. In the elims these stackers will have superior ability to come back in the 2nd round or run away with match in the 1st b/c they can score more points than their opponents ever can.

ngreen 13-03-2003 00:17

Stacking takes commitment
 
If you are an internal stacking planning on protecting a stack and set it down at the last minute while others are fighting for the KOH, you will need to stack at least five boxes to consistently win without KOH points. While my external stack can make several stacks of multiple boxes, not defend them and get the 25 points on top. If we lose all the stacks we still will win.

As mentioned above time is everything. Some choose to stack and move boxes into scoring areas during time, raising the game score. While some choose to attack the other teams boxes lowering the score.

With expecting to leave stacks undefended you make the other team make a choice. With 10 seconds left do they attack the stack of 5 or do they jet to the ramp. Either they gain points at the ramp and possibly win, if they can get past us, or they attack the stack and knock it down. But they still lose, we have 25 points they didn't get. And they didn't get a chance to finish off the stack of two we had. Stacker wins.

I know stacking will be difficult, we practiced for nearly two weeks with all of the bins. It can be done effectively if you can commit to it. I know I am but I still have to convince some of my less faithful team members.


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