Robot Arm C

[windu34]

What is the best way to regulate the voltage? With a 12V battery regulated to 5V and 12V with a high output of like 3-5 Amps.

I'm not sure, but maybe a dc-dc converter.

[nadroj]

No where in the rules am I finding a line that prohibits the competitors putting energy directly into the arm. I remember last time this event was on, this issue was very clear. No arms could be designed and operated using hydraulics that were powered by syringes being pushed in and out by the operator. Or am I missing something? Wondering because our grabber is powered by a small pneumatic cylinder. All air gauges need to start at 0 psi. Is it allowed to pump the air tank up with a simple bicycle foot pump as soon as the timer starts?? What do you all think?

[iwonder]

What is the best way to regulate the voltage? With a 12V battery regulated to 5V and 12V with a high output of like 3-5 Amps.

I'm not sure, but maybe a dc-dc converter.

Yup, pololu makes some 12-5 buck converters that run up to 5 amps. Make sure the wire's a bit heavier gauge than normal.

[jander14indoor]

No where in the rules am I finding a line that prohibits the competitors putting energy directly into the arm. <SNIP>

Not official, one opinion, sometimes the committee gets it wrong and overrules me, etc...

I don't see anything that clearly makes it illegal (though I'm still thinking on that) so probably not a construction violation. But I'd say it immediately stops the time, para 6.g. "The run must stop...when... iv. The competitors impart energy directly into the arm, base, Goal Cartons, or Scoreable Items."

Based on that, I'd stop the time as soon as you start pumping. Increasing the pressure in a reservoir (increased potential energy) or moving the piston (increased kinetic energy) is clearly imparting energy directly into the system.

Jeff Anderson
Livonia, MI

[nadroj]

ok, but we could flip a switch to kick over a small battery powered aircompressor to do the job. This went over fine last time.

[windu34]

ok, but we could flip a switch to kick over a small battery powered aircompressor to do the job. This went over fine last time.

I feel like you would be fine and within the rules, but I would try to stay away from hydrqulics in general.

[RockinScott]

Hi:

I am assisting my daughter in this project for a class, although we are following the official rules. A few comments:

1. Being a lawyer I have noticed that if the dice are not scorable items (and they are not) and the competition stops if you impart energy directly to the scoreable items or goals or the arm, it says nothing about imparting energy directly to the dice which apparently are in an unknown category of things as they are also not "items." In other words, move them with your hands. Just saying.

2. our idea for turning all of the dice at once is to have a single purpose arm project out from the base over the dice. at the end of the arm is a servo with a paddle (passive effector) that goes left to right from the first dice to the last. On the bottom side of the paddle is two sided tape. The main arm pushes down on the paddle to affix the tape to all 4 dice at once. The arm is raised slightly by another servo to create a bit of room for rotation. Then the servo at the end rotates 180 degrees and now all dice are 6's up siting on the paddle. Extend the arm further into the north zone to get clearance from the legos. it is not clear to me if one could just leave the arm and dice like that or the paddle needs to be removed from that arm. If it must be removed from the arm and set on the comp surface, I have figured that out . . .but will leave that detail up to you.

3. I think that there will be many perfect scores. Because all of the items are very light, they can all be picked up in bulk or individually with two sided tape-based effectors.

[chalker]

1. Being a lawyer I have noticed that if the dice are not scorable items (and they are not) and the competition stops if you impart energy directly to the scoreable items or goals or the arm, it says nothing about imparting energy directly to the dice which apparently are in an unknown category of things as they are also not "items." In other words, move them with your hands. Just saying.

Interesting observation. We might have to issue a clarification on that. Note we can always rely on General Rule #1 and say it's a spirit of the competition violation.

.... it is not clear to me if one could just leave the arm and dice like that or the paddle needs to be removed from that arm. If it must be removed from the arm and set on the comp surface, I have figured that out . . .but will leave that detail up to you. ...

As usual, this isn't the place for official comments or clarifications. However 7.e. states 'sitting flat', which could be nitpicked by an event supervisor if you aren't making contact with the competition surface somehow

3. I think that there will be many perfect scores. Because all of the items are very light, they can all be picked up in bulk or individually with two sided tape-based effectors.

Based upon previous year's experience, we don't expect a lot of perfect scores. You'd be surprised how many teams assume this is going to be easy but end up not practicing enough and make basic mistakes.

[windu34]

3. I think that there will be many perfect scores. Because all of the items are very light, they can all be picked up in bulk or individually with two sided tape-based effectors.

Based upon previous year's experience, we don't expect a lot of perfect scores. You'd be surprised how many teams assume this is going to be easy but end up not practicing enough and make basic mistakes.

I agree with RockinScott on this one, I definetly would expect at least 5 perfect scores. I have gotten several perfect scores (about 3/20 practices so far) and have just started practicing. It only took about 10-12 practices to start getting all items moved within the 3 minutes. By nats, that ratio is going to go way up. The only thing that should stop most of the teams from getting a perfect score at the national level will be mistakes. The dice part is probably not going to be the most important tiebreaker either since most teams will come up with a surefire consistent way to flip them. I believe only time will separate the top 5 or so teams (seeing as how there were 5 or 6 perfect scores at nats in 2013 and nothing about the event really got harder).

[RockinScott]

I did submit a request for a clarification but never heard back.

If the dice can be even side up in a goal, they should not have to be on the surface since being in a goal is not being on the surface either.