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MAteo9944 20-03-2007 21:39

Mecanum Defense
 
I was wondering if anyone has pondered the merits of holonomic drive in a defensive situation.
Most "defensive" robots utilize powerful drive trains to push their opponents around the field to keep them from scoring. This is obviously an effective method of defense but last week at the Peachtree regional I found another.

During one of our qualifying rounds our alliance partners asked us to defend against a very strong scoring robot. At first I protested because I didn't think our robot's mecanum drive was up to the challenge. As the match began I found that it was incredibly easy to stay between the other robot and the rack, making it very difficult for them to score. During the match they were only able to score one tube while I was tangled in the rack.

Our robot may not have been very powerful but it was able to keep the other team from scoring. This kind of defense is not effective for all game types but for Rack and Roll it works quite well.

KTorak 20-03-2007 21:42

Re: Mecanum Defence
 
This type worked well last year as well, because you could get between the robot shooting and the goal. In 2005, is it my poor memory or do I not remember much defense being played?

CraigHickman 20-03-2007 21:45

Re: Mecanum Defence
 
From the LA regional (I watched a highlight match video) the Harker bot on mechanums defended against the Poofs by knocking tubes out from in front of the repeatedly. Mechanums are great for maneuverable, strategic defense... But you still can't beat a brute force system that can politely escort any other robot across the field.

hillale 20-03-2007 21:45

Re: Mecanum Defence
 
That is how we, team 1625, played defense at our regionals. We were able to push/stop most robots in 1st gear, however, it turned out to be a much better idea to block access to the rack. Especially with the maneuverability of the swerve drive.

XaulZan11 20-03-2007 21:55

Re: Mecanum Defence
 
Quote:

Originally Posted by hillale (Post 602060)
That is how we, team 1625, played defense at our regionals. We were able to push/stop most robots in 1st gear, however, it turned out to be a much better idea to block access to the rack. Especially with the maneuverability of the swerve drive.

1625 was amazing at defending 71. They used thier swerve drive to stay infront of the Beast.

Against some teams, speed can be just as valuable than power. If you can't catch a team, you can't push them. But you can stay infront of a team and shield them from the rack, if you have speed and not power.

Dan Petrovic 20-03-2007 22:03

Re: Mecanum Defense
 
You are correct.

We managed to keep the Technokats (:ahh: ) from scoring for most of the match. We simply put ourselves between the rack and their robot.

Another thing we developed was a strategy where the defending team stays between the rack and the opposing robot (opposing robot very close to a position to score). The two robots push against eachother and the defending robot quickly moves out of the way. The opposing robot doesn't expect it and drives forward at full power, thus overshooting the goal. They now need to spend some more time re-aligning.

Frew 20-03-2007 22:23

Re: Mecanum Defense
 
well there is another way which i found very easy to do...im with team 1555 and you dont really need all that big of a transmission ...all we used was the banebots transmission you are given in the kit... well most robots this year are very easly pushed just by hitting there corners and turning them 180 degrees... this way you can take on more than 1 robot....which i was able to do many many times

geeknerd99 20-03-2007 22:50

Re: Mecanum Defense
 
From what I hear, we ended up as number one in defense on many team's scouting lists, just because of how manueverable we were. If you turn your ramp towards them and stay in between the other robot and the rack, it's almost like holding a poster and walking. Bonus points if you slap them-ahem-the tube with the ramp.

Rick-906 20-03-2007 23:42

Re: Mecanum Defense
 
our holonomic drive was actualy fairly good at getting us into the way of robots trying to score, though most of the time we were the ones scoring:D
it also makes it easy to drive circles around torqued up 6 wheelers trying to play rough D.

rachal 20-03-2007 23:47

Re: Mecanum Defence
 
Quote:

Originally Posted by 114ManualLabor (Post 602059)
From the LA regional (I watched a highlight match video) the Harker bot on mechanums defended against the Poofs by knocking tubes out from in front of the repeatedly. Mechanums are great for maneuverable, strategic defense... But you still can't beat a brute force system that can politely escort any other robot across the field.

We were able to get in Bellarmine's way a lot, but against bots with average or greater than average pushing power, the mecanums were only useful for knocking away tubes. We got frequently pushed into the rack and it was hard to prevent good top-scorers (i.e. Beachbots) from scoring over us.

Quote:

Originally Posted by KTorak (Post 602057)
This type worked well last year as well, because you could get between the robot shooting and the goal. In 2005, is it my poor memory or do I not remember much defense being played?

Yeah...I remember there being much stricter penalties for pushing/robot contact in 2005.

Jeremiah Johnson 21-03-2007 00:26

Re: Mecanum Defense
 
Quote:

Originally Posted by Rick-906 (Post 602165)
our holonomic drive was actualy fairly good at getting us into the way of robots trying to score, though most of the time we were the ones scoring:D
it also makes it easy to drive circles around torqued up 6 wheelers trying to play rough D.

I agree... with our (648) swerve drive we were able to outmaneuver most robots with good drivetrains at MWR. We could also push a lot of robots.

I saw that 858 had a good defensive robot in the qualifiers, but one they got into the elims they were very ineffective at defending teams. Same for 1000, our partner and the number 1 seed.

Edit: Both 858 and 1000 had tank drive.

Darkforces 21-03-2007 11:07

Re: Mecanum Defense
 
We holonomic drive this year and before we got our arm to function we played d. Since we could srafe back and forth we could gaurd almost half the rack by our self. Just as long as we dont get into any pushing matches

EricH 21-03-2007 14:57

Re: Mecanum Defense
 
Watch 1138's matches from L.A. to see how to use a mecanum to slow down two robots. You did not want to be against them if you were a tube robot.

SU 39 02-04-2007 21:29

Re: Mecanum Defense
 
At Lone Star Regional, team 118 (Robonauts) used a "v6 engine"
http://youtube.com/watch?v=h3l6Xqts4to
they basically put together 6 motors to create a monster v6 engine. Their arm was very quick and effective, allowing them to score a row of 8 by themselves. We *team 846* had saw that video before we arrived at the regional and were somewhat curious how we were going to defend them. When our match against them finally came, we just double teamed their robot, eventually blowing out their v6, forcing them to use their backup v6.
A double team can easily force a blown engine = great defense. :cool:

Justin Ridley 03-04-2007 00:13

Re: Mecanum Defense
 
Quote:

Originally Posted by SU 39 (Post 610125)
When our match against them finally came, we just double teamed their robot, eventually blowing out their v6, forcing them to use their backup v6.
A double team can easily force a blown engine = great defense. :cool:

Hmmm... not sure where you heard that.

During quarter final match 1 we took a hit that caused some electrical problems in the robot. Our frantic troubleshooting caused other problems and we were never fully functional the rest of the tournament. It was a struggle to get a robot out on the field after each tough match which followed. It seemed everything that could go wrong with the robot went wrong... except the V6. There was no "blown engine"... just one that came out of gear due to a hard hit in the last match.


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