Sumo Bots C

StaticBridge
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Re: Sumo Bots C

Postby StaticBridge » April 17th, 2011, 1:30 pm

Yea i suppose vex is the easiest way to build a working robot but i think that a custom built has more potential if you have time to perfect it.

This is our third custom built this year but all of them have worked very well and we seem to be improving steadily. :D

On a different note what types of batteries are you guys using?
Our team used Lithium Polymer batteries. They are extremely light and tend to work well. The only problem is you have to make sure you charge them because when they get below 3 volts or so they become extremely difficult to charge.

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Primate
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Re: Sumo Bots C

Postby Primate » April 17th, 2011, 3:09 pm

Yea i suppose vex is the easiest way to build a working robot but i think that a custom built has more potential if you have time to perfect it.

This is our third custom built this year but all of them have worked very well and we seem to be improving steadily. :D

On a different note what types of batteries are you guys using?
Our team used Lithium Polymer batteries. They are extremely light and tend to work well. The only problem is you have to make sure you charge them because when they get below 3 volts or so they become extremely difficult to charge.
If you use an ESC with a low voltage cutoff, which most of the good ones have, you shouldn't have to worry about overdischarging a LiPo.
events 2012 gravity vehicle, robot arm, thermodynamics, tps

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Re: Sumo Bots C

Postby whadk » April 17th, 2011, 3:48 pm

I think Vex batteries can also work out as fine. Batteries like Li stuff are good but, they have memory system.
But when using the custom built, I think anything around 12v would be fine (since that's around the limit).
It's more of the structure of robot that decides the strength and speed.
Speaking of which, if your robot has extra room for weight, put some masses on wherever you think they should be. It helps a lot.
Usually near the wheels.
RWARRRR :)

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ichaelm
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Re: Sumo Bots C

Postby ichaelm » April 17th, 2011, 4:50 pm

As far as I know, lithium polymer batteries don't have a memory effect, as long as they don't get carelessly over-discharged.

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Re: Sumo Bots C

Postby hscmom » April 17th, 2011, 6:12 pm

Well good luck!

In the end it all comes down to who is the better driver. It doesn't matter how much you can push if you can't drive under the other bot...
Then again, we were "driven under" and managed to push the other team out while on top of them yesterday at States. Wish we were going to Nationals but our team is just not there (it's our second year and we're young -- nobody has a driver's license yet!!). The girls built the bot in four weeks (our team's sumobot dude quit right after Regionals so we had to start from scratch) and I hate that it's not an event next year. Oh well, my daughter's 14 so she's got a few more years for it to cycle back around again. That was fun.
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whadk
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Re: Sumo Bots C

Postby whadk » April 17th, 2011, 7:39 pm

Well good luck!

In the end it all comes down to who is the better driver. It doesn't matter how much you can push if you can't drive under the other bot...
Then again, we were "driven under" and managed to push the other team out while on top of them yesterday at States. Wish we were going to Nationals but our team is just not there (it's our second year and we're young -- nobody has a driver's license yet!!). The girls built the bot in four weeks (our team's sumobot dude quit right after Regionals so we had to start from scratch) and I hate that it's not an event next year. Oh well, my daughter's 14 so she's got a few more years for it to cycle back around again. That was fun.
Well by being driven under the bot, usually you will lose if the other robot was designed to make u go on top of it so that u'll completely lose control of your robot.
Mostly, plated robots that get under your bot are wide enough to disable your robot's wheels where you try to back up but the robots are pushing forward as well.
The thing about these robots, once you fall inside the trap, it's really really hard to get out.
RWARRRR :)

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sj
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Re: Sumo Bots C

Postby sj » April 21st, 2011, 8:20 am

Has anyone had any success with covering wheels with tape?
If so what type of tape did you use and how did you prevent it from just sticking to the floor and peeling off the wheel?
2011 Nationals Results : Sumo Bots 2nd, Helicopters 4rd, Mission Possible 4th, Towers, 9th
WWP SOUTH 3rd At NATS!!!!!

2012 Events: Robot Arm, Towers, Gravity Vehicle

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Re: Sumo Bots C

Postby Balsa Man » April 21st, 2011, 11:32 am

Has anyone had any success with covering wheels with tape?
If so what type of tape did you use and how did you prevent it from just sticking to the floor and peeling off the wheel?
Couple thoughts that might help you.
Double-sided tape is one option; either like double-sided scotch tape, or the double-sided (thin) foam tape is an option. Two problems-if it's sticky enough to really stick to your wheels- depending on what your wheels are made of, you may want to put/paint something around them that the tape sticks to well (maybe rubber cement?). Second problem is dirt pick-up/cleaning. We played with this some before going with moulding tires out of polyurethane rubber; good traction when fresh and clean. However, even on a reasonably cleaned floor, tape will quickly and very efficiently pick up dust/dirt, and the stickyness will go away fast. Cleaning (we used WD-40 to clean poly wheels) is a major problem with tape, because anything that's a good cleaner will pretty quickly remove the tape stickyness along with the dirt.
The bot that won State here used nice, wide black foam rubber (from an RC vehicle). Those provide decent traction, but not great. They'd put a number of wide rubber bands around those wheels; its a matter of finding the right size for your wheels. Rubber band rubber provides a very good coefficient of friction, and its cleanable between rounds. Definately worth checking out.
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sj
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Re: Sumo Bots C

Postby sj » April 21st, 2011, 11:37 am

We tried balloons and rubber-bands but short of anything sticky the rubber on our wheels is better. As for tape we were planning on making it replaceable between rounds.
2011 Nationals Results : Sumo Bots 2nd, Helicopters 4rd, Mission Possible 4th, Towers, 9th
WWP SOUTH 3rd At NATS!!!!!

2012 Events: Robot Arm, Towers, Gravity Vehicle

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sj
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Re: Sumo Bots C

Postby sj » April 26th, 2011, 3:18 pm

For the competition surface at nationals does anyone know if it is going to be for panels put together like last year or one solid piece of plywood?
2011 Nationals Results : Sumo Bots 2nd, Helicopters 4rd, Mission Possible 4th, Towers, 9th
WWP SOUTH 3rd At NATS!!!!!

2012 Events: Robot Arm, Towers, Gravity Vehicle


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