View Full Version : Minibot Questions
Instead of making a new post for each question that was about the same mechanical component, I decided to make one post for all.
1) Can we use a clevis and control horn like the ones used in RC Airplanes to Open/Close the hinge mechanism to hold the minibot to the pole?
http://www.servocity.com/assets/images/GPMQ3900_Control_Horns_with_rod.jpg
2) Since coiled metal springs are not allowed on the minibot (http://forums.usfirst.org/showthread.php?t=16517), and our team was planning to use compression springs to keep the "jaws" open until the minibot reached the pole, what substitution with surgical tubing could we use to keep the "jaws" open until the minibot reaches the pole.
3)Could we use polycarbonate pulleys for our closing plunger mechanism. They won't be contributing to any vertical movement, only to guide cable so they can pull the "jaws" close.
http://www.servocity.com/assets/images/56314_1.5.jpg
big1boom
28-01-2011, 17:10
1) No, unless you make it yourself out of raw aluminum sheet. <R92-H>
2) You can make your own compression spring by taking a piece of polycarbonate, and simply bending it. <R92-F>
3) My first assumption is that polycarbonate pulleys are illegal, but I would suggest a Q&A on this one.
3) My first assumption is that polycarbonate pulleys are illegal, but I would suggest a Q&A on this one.
GDC isn't saying anything about form polycarb can take, other than a very broad "Polycarb is legal, and there are no restrictions on form" in http://forums.usfirst.org/showthread.php?t=16317
Henry Williams
28-01-2011, 17:24
I'm pretty sure for the poly pulleys you would have to make your own for it to be leagal, however I am not sure enough that you should give up, I agree with the suggestion to Q&A that.
Won't polycarbonate snap if it's bent so far?
Would a steel cable be considered legal?
Won't polycarbonate snap if it's bent so far?
Not if you do it right. Not being entirely certain of the method there, I'd say to find 1714 (or Chris is me) and ask them.
Steel cable: Not legal on the Minbot. You can use non-metallic rope or cord.
Henry, check the Q&A I linked to again.
Henry Williams
28-01-2011, 17:37
Oh,okay sorry about that then.
Another question that goes off topic from here.
Would it be illegal to use a jaw and cone clutch for our minibot mechanism? It would be connected to one of the motors the main drive OR just another motor we have running and propel the launching mechanism forward until a limit switch stops it.
Henry Williams
30-01-2011, 21:34
As far as bending polycarb goes, it helps if you heat it first. We have an electric heater for just that purpose but you can also get the job done with a Heat gun if you're careful. But as you bend it (especially past 90 degrees) the material gets thinner and slightly more brittle (because you are actually stretching it) so it does have its limits. We had to get pretty good at this for our minibot
PAR_WIG1350
30-01-2011, 23:21
Another question that goes off topic from here.
Would it be illegal to use a jaw and cone clutch for our minibot mechanism? It would be connected to one of the motors the main drive OR just another motor we have running and propel the launching mechanism forward until a limit switch stops it.
I don't think that would be legal, unless you could built it out of the allowed materials.
Al Skierkiewicz
30-01-2011, 23:24
Another question that goes off topic from here.
Would it be illegal to use a jaw and cone clutch for our minibot mechanism? It would be connected to one of the motors the main drive OR just another motor we have running and propel the launching mechanism forward until a limit switch stops it.
Only if you can construct one using the allowed materials in R92 and you have two or less Tetrix motors.
UnderAverageJoe
31-01-2011, 12:52
does anyone know what we can do to get the minbot down from the top of the pole? can we shake it? and we bring large extensions to get it down?
does anyone know what we can do to get the minbot down from the top of the pole? can we shake it? and we bring large extensions to get it down?
No specific prohibition against shaking the pole yet from GDC but Update #6 specifically prohibits use of any mechanism (stick, etc) from being used to retreive your minibot...
kbrowncny
31-01-2011, 13:08
How about threaded Aluminum rod. Is that permitted for use on the minibot?
Al Skierkiewicz
31-01-2011, 13:13
Modified by TU #6
<G59> TEAMS must retrieve MINIBOTS from the TOWER quickly and safely without special equipment and while standing on the floor after each MATCH. Violation: The FIELD crew will retrieve the MINIBOT. A second violation may result in a YELLOW CARD.
It is expected that a MINIBOT will be able to be retrieved from the TOWER in less than 1 minute. If the FIELD crew has to retrieve the MINIBOT, they are not responsible for incurred damage to the MINIBOT. If a MINIBOT is deemed dangerous (i.e. in its design, or in the way the TEAM retrievese it from the TOWER), the Referee may issue a YELLOW CARD to the TEAM associated with the MINIBOT.
As to threaded rod, only if you can make it from...
H. Raw aluminum sheet, 90° angle, u-channel, tube, bar, that is not sold in pre-perforated or pre-punched form.
As to threaded rod, only if you can make it from...
H. Raw aluminum sheet, 90° angle, u-channel, tube, bar, that is not sold in pre-perforated or pre-punched form.
I would suspect that you could get round Al bar and thread it. Whether you can get it to fit into the Minibot volume and still come down enough to get the Minibot easily is a little trickier.
I would suspect that you could get round Al bar and thread it. Whether you can get it to fit into the Minibot volume and still come down enough to get the Minibot easily is a little trickier.
I suggest teams put a hook or ring on their robot that gives an obvious place for the Field Personnel to grab the minibot. You should do this even if you are planning to have the robot bring itself down because things don't always go according to plan.
ChrisH
Vikesrock
01-02-2011, 00:15
As to threaded rod, only if you can make it from...
H. Raw aluminum sheet, 90° angle, u-channel, tube, bar, that is not sold in pre-perforated or pre-punched form.
GDC decided it's a fastener:
http://forums.usfirst.org/showthread.php?t=16667
Hello Everyone! Does anyone have any ideas whatsoever abut the deployment of the Mini-bot? any advice or ideas from any team would be treated with the utmost appreciation!! Thank You! :)
Team 2389
Hello Everyone! Does anyone have any ideas whatsoever abut the deployment of the Mini-bot? any advice or ideas from any team would be treated with the utmost appreciation!! Thank You! :)
Team 2389
Go to Youtube, type in FRC minibot and observe closely;)
PAR_WIG1350
01-02-2011, 14:15
Couldn't threaded rod be considered a mechanical fastener?
Couldn't threaded rod be considered a mechanical fastener?
At the time I made that post, it was unclear. Someone asked Q&A, and it is considered a fastener by the GDC. Therefore, it is a fastener for FRC purposes (whether or not is is actually a fastener).
does annyone know if there are any spefications on the aluminum sheet. ex. thickness, limited amount. and does anyone know if we can use pvc sheet or does it have to be tubing
Mike Wittman
01-02-2011, 18:55
Not if you do it right. Not being entirely certain of the method there, I'd say to find 1714 (or Chris is me) and ask them.
Steel cable: Not legal on the Minbot. You can use non-metallic rope or cord.
Henry, check the Q&A I linked to again.
Polycarbonate can be cold bent, and in most cases it will not break. It can be bent in an apron break or a press break. If you are going to bend it over onto itself you will need to stress release the material with heat. Many hobbyists do it with a heat gun.
If you are looking for a spring tension, you could stack layers of different thickness to create a leaf spring. This will allow you to play with different tensions. It is very unlikely that you will break Polycarbonate using it this way.
Al Skierkiewicz
01-02-2011, 19:37
does annyone know if there are any spefications on the aluminum sheet. ex. thickness, limited amount. and does anyone know if we can use pvc sheet or does it have to be tubing
The GDC answered that anything marketed as sheet is sheet. The rule in other words reads PVC pipe or fittings CPVC pipe or fittings. Sheet PVC is not part of the rule.
Is it possible that we can have anotehr FRC team with a water jet cutter to cut our minibot sheet metal on a CAD file?
Al Skierkiewicz
04-02-2011, 18:22
Yes,
There is no restriction in the minibot rules that prevents you taking advantage of someone's watergenerosity.
Anyone generous out there? :)
Brian Ha
04-02-2011, 20:25
Umm, we have our wheels basically drop their power or however you would actually word it, and then drop. We plan on putting some foam underneath it, both the minibot and the deployment system because the first time we did it, some things fell out, then we did it again without fixing it, and some more things came off. So you might want to have it free drop, but have some sort of thing to either cushion its fall or prevent it from hitting the ground intensly hard.
We plan on putting some foam underneath it, both the minibot and the deployment system because the first time we did it, some things fell out, then we did it again without fixing it, and some more things came off. Umm... Can someone tell me where to find "foam" of some form in <R92>?
Deployment system, go for it. Minibot, start thinking creatively. Hmmm... stretch surgical tubing on the bottom of the Minibot, maybe?
Al Skierkiewicz
05-02-2011, 08:53
Brian,
Is the foam going on the minibot or on the robot deployment device?
phoebe.patwell
05-02-2011, 10:12
Does anyone have specifications on the non-slip pad? It seems quite vague and open to interpretation, but I don't know what would qualify as non-slip pad and would appreciate it if anyone else has investigated it could tell me some options.
Vikesrock
05-02-2011, 10:17
Does anyone have specifications on the non-slip pad? It seems quite vague and open to interpretation, but I don't know what would qualify as non-slip pad and would appreciate it if anyone else has investigated it could tell me some options.
Q&A clarifies a little bit here:
http://forums.usfirst.org/showthread.php?t=16456
To Eric, Team 330 and Al Team 111.
1. Can your minibot change shape as its going up the pole? We have are battery swing down outside the 12x12x12 dementions. Gravity takes over. Cocking the wheels on the pole. We want most of are weight on the bottom.
2. I have one local Lead Inspector say. Here is a 12x12x12 box. Set your minibot inside. Close the lid. Your good to go. Meaning to me, that while the robot is inside. It can rest on the sides of the box. I said, I don't think so.
You can not touch the sides. At a recent FTC event. The students were told.
Set your robot on the table right here. Down comes the inspectors arm. With a 18x18x18 inch box. Over top the robot. It better not touch anything. I feel, I will be inspecting the minibot that way. Which way is it Al and Eric?
P.S. Eric, I look forward to inspecting Team 330 some day. To see if the students have read the manual.
Robot Inspector
Thomas (just give me a crabcake) McCubbin
Mt. Airy, MD. Team 686
God Bless both of you!
Vikesrock
05-02-2011, 11:01
To Eric, Team 330 and Al Team 111.
1. Can your minibot change shape as its going up the pole? We have are battery swing down outside the 12x12x12 dementions. Gravity takes over. Cocking the wheels on the pole. We want most of are weight on the bottom.
I'm not Al or Eric, but the GDC has answered this one in the Q&A. The minibot must remain in the 12x12x12 dimensions during the whole match.
http://forums.usfirst.org/showthread.php?t=16288
Al Skierkiewicz
06-02-2011, 10:14
Your minibot can change shape but it may not exceed the 12 inch cube. EVER!
As stated there will be a box to set your mini inside. A robot inspector will check all configurations. The minibot can touch the sides but it cannot be constrained by the box. In other words if it larger than the box but can be forced to fit, it will not pass.
Mac,
I removed your phone info. There are a lot of people that are not robot people who get on to this board. I didn't want you flooded with calls.
Brian Ha
11-02-2011, 09:42
Brian,
Is the foam going on the minibot or on the robot deployment device?
At the moment I'm not sure seeing as I'm not a part of their group. But from last night it seems to come down a little (enough to grab it) and then stop. From what was talk was going on earlier on the deployment system if i remember correctly
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