Robot Arm C

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Re: Robot Arm C

Post by Primate » January 30th, 2012, 4:55 pm

ichaelm wrote:I think the better question to ask here is WHY make it autonomous, not why not. A team that gets maximum score with an autonomous 4-motor robot will not beat one that gets maximum score with 4 motors that's manually controlled. Time is not scored. It will come down to the quality of technical documentation. So why put in all the extra effort with inverse kinematics and making is sturdy enough to be dead accurate with those nails, when it doesn't help your score at all? The only answer I can think of is because it would be fun, of course! But in terms of building a better bot, I can't justify it. If I were you, I'd put more time into making sure the physical bot itself is reliable, and of course some 3D modeling to win the all-important second tiebreaker!
Oh god, I'm staying far away from inverse kinematics. I'm positive that's not worth it, unless you can find a decent library. I'm just preprogramming servo positions in a sequence. If you've got five joints, the computer will be much faster at moving from point a to point b because it can move all five servos at the same time. Then you hop in before it picks up or drops the object to tweak the positioning.
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Re: Robot Arm C

Post by ichaelm » January 30th, 2012, 4:59 pm

Oh, that's pretty cool! But still, I see you point to speed as the advantage. My teammates haven't had a chance to practice with a real field compliant with the rules, but my my judgement, it shouldn't be a problem to make 3 minutes. I guess that depends on your controller, and practice.

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Re: Robot Arm C

Post by chalker7 » January 30th, 2012, 7:38 pm

ichaelm wrote:I think the better question to ask here is WHY make it autonomous, not why not. A team that gets maximum score with an autonomous 4-motor robot will not beat one that gets maximum score with 4 motors that's manually controlled. Time is not scored. It will come down to the quality of technical documentation. So why put in all the extra effort with inverse kinematics and making is sturdy enough to be dead accurate with those nails, when it doesn't help your score at all? The only answer I can think of is because it would be fun, of course! But in terms of building a better bot, I can't justify it. If I were you, I'd put more time into making sure the physical bot itself is reliable, and of course some 3D modeling to win the all-important second tiebreaker!
I have to agree here a bit. Of course it would be extremely fun and very interesting to build a fully autonomous robot, but unless you have accurate sensors telling the robot where to move, you could be thrown off very early in your run. While the rules have specific placement points and dimensions for every object in the playing field, supervisors are human and small variations could (almost certainly will) be present between different runs. It's probably safer to be able to directly control the robot in case you miss an object on the first attempt.
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Re: Robot Arm C

Post by Primate » January 30th, 2012, 8:48 pm

ichaelm wrote:Oh, that's pretty cool! But still, I see you point to speed as the advantage. My teammates haven't had a chance to practice with a real field compliant with the rules, but my my judgement, it shouldn't be a problem to make 3 minutes. I guess that depends on your controller, and practice.
Yeah, I'm (still) all theoretical here. I was watching teams at invitationals (which, granted, doesn't inspire people to prepare too hard), and of the two teams that had a capable arm, only one managed to get more than twenty points...

one week 'til regionals. shoot.
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Re: Robot Arm C

Post by NinjaChicken » January 31st, 2012, 6:52 am

Primate wrote: Yeah, I'm (still) all theoretical here. I was watching teams at invitationals (which, granted, doesn't inspire people to prepare too hard), and of the two teams that had a capable arm, only one managed to get more than twenty points...

one week 'til regionals. shoot.
Holy cats, one week? We're not even getting our shipment in for robot arm until Thursday, I'd be freaking out soo badly if our regionals were that soon... Ours aren't until March 17, and I'm still worried!
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Re: Robot Arm C

Post by nadroj » January 31st, 2012, 9:12 am

We are planning to operate the gripper part of our robot arm using pnumatics. To do this we made a small homemade air tank. Can anyone tell me if this will be problematic? Will this disqualify my becuase of safety concerns that I am not using a comerically made cannister? Perhaps someone can point me to where I can find specifics on the use of compressed air tanks/cannisters in Science Olympiad events. Thanks.

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Re: Robot Arm C

Post by chalker » January 31st, 2012, 10:20 am

nadroj wrote:We are planning to operate the gripper part of our robot arm using pnumatics. To do this we made a small homemade air tank. Can anyone tell me if this will be problematic? Will this disqualify my becuase of safety concerns that I am not using a comerically made cannister? Perhaps someone can point me to where I can find specifics on the use of compressed air tanks/cannisters in Science Olympiad events. Thanks.

I don't think we have explicit guidelines regarding compressed air, although you can look at the bottle rocket event for the types of precautions typically taken. Regardless, why use a home-made tank? Compressed air has a surprising amount of energy stored in it, and in all likely-hood your home-made tank won't hold anywhere near the pressure a store bought on would.

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Re: Robot Arm C

Post by jander14indoor » February 1st, 2012, 12:54 pm

As usual, not the place for clarifications, etc.
nadroj wrote:We are planning to operate the gripper part of our robot arm using pnumatics. To do this we made a small homemade air tank. Can anyone tell me if this will be problematic? Will this disqualify my becuase of safety concerns that I am not using a comerically made cannister? Perhaps someone can point me to where I can find specifics on the use of compressed air tanks/cannisters in Science Olympiad events. Thanks.
Hmm, the only place we mention pnuematics is para 7.j.i which certainly implies pnuematics are allowed. The only way I'd see it as problematic would be a safety call by the event supervisor.
As a starting point I'd think the pressures and containers (there is a reason the rules require use of a bottle meant for carbonated beverages!) of bottle rocket would be arguably safe.
Alternatively a purchased pressure vessel with labled certified capacity operated well within that capacity should be OK.
Completely home-made would make me nervous as an event supervisor. Has it been pressure tested, how? What is the test level vs operating level? What is the failure mode (doe the material shatter & scatter shrapnel or expand, split a seam and release pressure safely)? Even if all that testing and evaluation has been done and data is available, am I qualified to judge it?

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Re: Robot Arm C

Post by Flavorflav » February 4th, 2012, 2:28 am

Chalkers, and any other individuals reading this who have the ability to provide input into next year's rules, would you consider lightening the paperwork requirements? My lead robot guy spent five hours yesterday doing the documentation in preparation for our regional today. That's a lot of time for something that isn't even being graded except as "complete" or "incomplete," and which by its nature has to be done at the end, so doesn't really reflect the design process. It also doesn't prevent Daddy-builts, either, as far as I can tell, which makes it seem like hoop-jumping. Yes, I know it is something that real engineers probably do, but we don't require it in tower where it would be easier and arguably more useful.

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Re: Robot Arm C

Post by chalker » February 4th, 2012, 8:05 am

Flavorflav wrote:Chalkers, and any other individuals reading this who have the ability to provide input into next year's rules, would you consider lightening the paperwork requirements? My lead robot guy spent five hours yesterday doing the documentation in preparation for our regional today. That's a lot of time for something that isn't even being graded except as "complete" or "incomplete," and which by its nature has to be done at the end, so doesn't really reflect the design process. It also doesn't prevent Daddy-builts, either, as far as I can tell, which makes it seem like hoop-jumping. Yes, I know it is something that real engineers probably do, but we don't require it in tower where it would be easier and arguably more useful.
5 hours doesn't seem that unreasonable to me.. particularly compared to how much time many students put into various studying events learning various topics, many of which they end up not being tested on at all. In addition, the grading isn't truly 'pass' / 'fail'. If you look at the scoring formula you can have anywhere from a 0% to 30% (in 5% increments) impact on the scores (thus instead of a 2 value grading rubric we essentially have a 7 value rubric).

That said, we are always open to suggestions. We don't want this event to be a pure 'robot building' event, so we need to have some sort of additional component to it. Any ideas what else that could be?

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