So how many of you actually have a working minibot/deployment?

[davidthefat]

Originally Posted by squirrel

With a system like that, you have to balance the center wheel drop, with the wheel tread traction, and you probably want to run two CIMs per side. With sticky treads and not enough drop, and only one motor per side, it would be likely to not turn on carpet.

Oh, just great. That system worked fantastically last year. It is also true that we were actually very light too. My mentor says that the code is fantastic, the best handling in history, but that was on the concrete without an arm or minibot to weigh it down during week 2.

Oh and thank you, that is what I suspected. I have been pushing 2 motors since week one, but I guess the drive people thought the extra weight was not worth it.

[Koko Ed]

Originally Posted by pfreivald

I think there were two (2) successful MINIBOT deployments at the RaChaCha Rally (a big thanks to 1511 for hosting!)

We did it once, and then tried something different where we thought that perhaps our MINIBOT might fall out... and it did... After that we didn't load it onto the robot again, happy that what we have works the way we want it to work.

Other than that and one team I didn't get a chance to see, quite a few attempts but nothing successful.

191 managed to put up two complete logos, though, with an autonomous ubertube scored -- very impressive!

We finally got video of that match.

[Saber Robotics]

Again, I still cannot figure out this website so I am posting my question here. Many teams have stated that modifying the tetrix gearbox is the way to go, but no one has said exactly what they did to make their own gears, or where they found their own.

So my question is, what exactly do we need to do to make our minibot climb faster? I understand removing weight, adding a gear ratio outside, or modifying the gearbox inside the motor are all viable solutions, but how should we go about doing this?

[Brandon Holley]

Originally Posted by Saber Robotics

Again, I still cannot figure out this website so I am posting my question here. Many teams have stated that modifying the tetrix gearbox is the way to go, but no one has said exactly what they did to make their own gears, or where they found their own.

So my question is, what exactly do we need to do to make our minibot climb faster? I understand removing weight, adding a gear ratio outside, or modifying the gearbox inside the motor are all viable solutions, but how should we go about doing this?

I'm confused to what you are asking. The ideas you listed are all viable options to increase minibot speed so why are you asking how to do it? FIRST provides an engineering challenge for us to solve, and it seems as you have some ideas as to solve the minibot challenge, so go out and do it.

Sure, someone here could hand you the exact answer your looking for and you will probably make a faster minibot. What are you learning from that? What's your team learning from that? Use the ideas you have and THINK about how to solve the problem. If you have specific questions about how to do something, myself or someone else would gladly help you out, but the impression I'm getting is you want the answer handed to you.

Best of luck, and if you have any specific questions I will gladly help you out!

-Brando

[maverickfan138]

573's minibot was complete three weeks ago and it climbed a pole even before then. Our minibot team has done an excellent job this year and they have enjoyed working on their part of the robot.

Our deployment structure is done. We were not able to test it because we are still waiting for a 4/1 banebots gearbox. We believe that it will be a solid deployment mechanism when we add the motor and gearbox though.

[Saber Robotics]

I apologize for seeming like we just want answers. Truth is we are down right scared to start digging around in the motors, this close to competition. We fear that our minibot is decent, at around 4.5 seconds not including deployment, and we were wondering what a good way to go about it is.

Sometimes we need to figure stuff out on our own and other times we dont have the knowledge to know what to do. So here is my updated question, what are some different ways that teams have modified the gearboxes on their tetrix motors. Are there available gears for purchase or is there a way to manufacture your own?

Again sorry that I misspoke and thanks for the help.

Originally Posted by Saber Robotics

I apologize for seeming like we just want answers. Truth is we are down right scared to start digging around in the motors, this close to competition. We fear that our minibot is decent, at around 4.5 seconds not including deployment, and we were wondering what a good way to go about it is.

Sometimes we need to figure stuff out on our own and other times we dont have the knowledge to know what to do. So here is my updated question, what are some different ways that teams have modified the gearboxes on their tetrix motors. Are there available gears for purchase or is there a way to manufacture your own?

Again sorry that I misspoke and thanks for the help.

I was on another forum pagem and someone said this one quote, "Some teams are still working on their robots, some refuse to improve. Improve or perish". We are working on our minibot and the deployment system, and will continue to work on it until March 31st (competition day). You can see our robot in this video: http://wghsrobotics.webs.com/apps/vi...4-rampage-2011 I made the video, and the website, all by myself! . Our minibot is at the very end. It goes up in less than 4.3 seconds, but we're still working on deployment and the speed of the minibot.

[boomergeek]

Buy more TETRIX motors.

We ordered two before we got the FIRST choice package.

I'm going to lobby to buy more.

If you have one working minibot in hand, I would advise you leave it alone until you have a second better working minbot in hand- Only after you reached that point should you consider cannibalizing the first minbot.

Yes, it's $40-60 for the motors depending on your school discount- but it is a huge stress reliever to have that working bot locked up safely while you experiment (especially if you are considering destructively ripping into the gearboxes)

[JosephC]

We got our Minibot up the pole in 3.14 seconds(not including deployment). We're also working on another minibot that's about half way done that should double our speed (to like 1.7 seconds). Our delivery system should be done tomorrow and "should" take 1 seconds to deploy but we'll see

[DonRotolo]

Originally Posted by Saber Robotics

Truth is we are down right scared to start digging around in the motors, this close to competition.

Get more motors. Break them instead of your 4 second minibot. You can't learn anything without breaking some stuff.

Inside you'll find four gears. Most of them match up with the others easily - that is, they (almost) all have the same "pitch". So, no need to buy more gears.

Play around with them for a while, figure out the output gear ratios for different combinations that can work, and write them down. (Note that the 'height' of the gears might not be right, sometimes you need to make spacers for the gears to get them the right height. The gear on the output shaft might need to be pressed off and you'll have to figure out how to hold it on at a different spot)

Then do the same for the tetrix gears and wheel combinations, then calculate the 'motor to wheel' gear ratios.

Pick a bunch of them - one at each end, a couple in the middle - to try out, see which works best. Keep careful notes of everything you do. Once you have the 'best', try more ratios that are closer to the 'best', and find the 'new best'. repeat until you have the best of the best, and build your minibot.

Does this process make sense to you? Of course, you need to do perhaps ten of these 'experiments' a day. Try to keep the weight of the frame of the minibot the same, make a switch system to start and stop it automatically, use a fresh battery every 4-5 runs, all to eliminate any variables that could fool you.

Good Luck.

[Nelson]

Our team has a working minibot, although It will probably change a lot between now and the Utah Regionals.

Originally Posted by Nelson

Our team has a working minibot, although It will probably change a lot between now and the Utah Regionals.

I believe EVERYONE'S minibots will change between now and their regionals!

[Nelson]

It gives a lot of work to keep us busy, which is what we all need.

Originally Posted by Nelson

It gives a lot of work to keep us busy, which is what we all need.

Exactly!

[KnexTechGuy]

We have a working minibot that can go up the pole in less than 10 seconds. It's got strong magnets to hold it, and a single drive wheel.