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 We'll defintely be working on both the balancing 2 wheel robot, the 6 legged robot, and the wood chassis 8 wheel drive robot ideas this fall. - MrForbes [more] |
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A 7.5" tall robot. It's so short that it's impossible for it not to be able to go under the low bar, unless you put the intake/shooter all the way up and flip the hook up as well.
Geared for 14fps, although that can be changed to up to 16fps by messing with the first stage CIM pulleys. Runs a 4-CIM drivetrain with 6" WCP pneumatic wheels.
Weight is 64lbs without bumpers or battery. It weighs 97lbs with bumpers and battery.
Shooter is powered by a single 775pro due to space concerns, and is at a 20:12 (not sure on that) reduction. The hood uses a REV smart servo and a gear rack to roll in and out up to a 20* change in shooting angle.
The intake and shooter move in and out via a two 775pro motors on a ~150:1 reduction with a VP and a small gear reduction. Hard stops are rubber and are integrated into the 4-bar linkage.
Not shown: a string that pulls the ball guide up so that the ball rests against it properly before the shot, rivets, encoders, a few screws here and there, and a couple mounting plates and wires for electronics. That being said, all the electronics are in there. I have space for the encoders but neglected to add them because I was so done with this project after the first few days.
CAD will be available on the 2015 offseason release, because I still haven't moved anything to a 2016 offseason folder. 
Things I would change/add:
-Encoders
-Climber (there's a design for one, but I haven't the heart to finish it)
-Extra shooter motor
-Better bumper supports (a welded sheet metal plate in the front and back would have done wonders)
and:
-CDF/Portcullis attachment.
Surprisingly, this was harder to do than a climber, at least in the packaging I wanted. I could tack it onto the intake with everything else, but as I said before I got really tired of this. Working inside the tiny envelope was fun, but definitely not something I would want to do in-season. That being said, I would be reasonably confident building this robot IRL.
I forgot to mention, the colors are blue and gold to match the colors of a new rookie team coming up next year!
Discussion
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10-08-2016 09:28
Kevin Leonard
Re: pic: 7.5" tall robot, ready to shoot
So would this theoretical robot be able to cross under the low bar while holding a ball? It seems like in order to do anything useful it needs to be in the taller position.
10-08-2016 10:02
SenorZ
Re: pic: 7.5" tall robot, ready to shoot
I like it.
I brought up a "collapsing" shooter idea after build season, as a side project.
My team all shook their heads. 
10-08-2016 10:40
Chris is me
Re: pic: 7.5" tall robot, ready to shoot
Is there anything locking the shooter in position when it is in the firing position? It seems at least plausible that the ball being forced into the shooter could cause the shooter to give a little bit while firing, and generally you want all the rigidity you can get with such a system for consistency reasons.
I like the intake and shooter articulating together as it probably adds a lot of consistency to the ball loading.
Just curious - how are you avoiding this mechanism tangling with the battery cable when it folds up?
10-08-2016 13:48
asid61
Re: pic: 7.5" tall robot, ready to shoot
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Originally Posted by Kevin Leonard
So would this theoretical robot be able to cross under the low bar while holding a ball? It seems like in order to do anything useful it needs to be in the taller position.
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Originally Posted by SenorZ
I like it.
I brought up a "collapsing" shooter idea after build season, as a side project. My team all shook their heads. |
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Originally Posted by Chris is me
Is there anything locking the shooter in position when it is in the firing position? It seems at least plausible that the ball being forced into the shooter could cause the shooter to give a little bit while firing, and generally you want all the rigidity you can get with such a system for consistency reasons.
I like the intake and shooter articulating together as it probably adds a lot of consistency to the ball loading. Just curious - how are you avoiding this mechanism tangling with the battery cable when it folds up? |
Battery cable- whats that? I see no cables...
Realistically though, the battery wires can easily just go down the sides of the battery without hitting anything or risking a nasty break.
10-08-2016 14:37
edesirim
Re: pic: 7.5" tall robot, ready to shoot
According to the rules, the ball has a diameter of 10". I just wanted to know if the intake folds up or something and the robot chassis itself? Just a clarifying question. 
10-08-2016 14:58
asid61
Re: pic: 7.5" tall robot, ready to shoot
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Originally Posted by edesirim
According to the rules, the ball has a diameter of 10". I just wanted to know if the intake folds up or something and the robot chassis itself? Just a clarifying question.
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10-08-2016 15:06
ThaddeusMaximus
Re: pic: 7.5" tall robot, ready to shoot
Love the battery packaging.
10-08-2016 15:07
Jeremy Germita
Re: pic: 7.5" tall robot, ready to shoot
I don't see any clearance for a tube fitting on your hood cylinders(picture). As it stands, you'll only be able to supply air to the retract side of the cylinder. It looks like you might have enough room to just space your shooter bearing plates a little more to clear a fitting, but I haven't looked at the CAD closely enough to see if this is possible.
Other than that, I really like the usage of the four-bar. I love seeing neat linkages on robots.
10-08-2016 15:35
asid61
Re: pic: 7.5" tall robot, ready to shoot
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Originally Posted by ThaddeusMaximus
Love the battery packaging.
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Originally Posted by Jeremy Germita
I don't see any clearance for a tube fitting on your hood cylinders(picture). As it stands, you'll only be able to supply air to the retract side of the cylinder. It looks like you might have enough room to just space your shooter bearing plates a little more to clear a fitting, but I haven't looked at the CAD closely enough to see if this is possible.
Other than that, I really like the usage of the four-bar. I love seeing neat linkages on robots. |
I think I can push the mounting plates out by another 3/8" at least, or add a hole to allow the fitting in.
Thank you!
10-08-2016 16:48
Greg Woelki
Re: pic: 7.5" tall robot, ready to shoot
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Originally Posted by asid61
Nooooo does this mean I have to re-render!?
I think I can push the mounting plates out by another 3/8" at least, or add a hole to allow the fitting in. |
10-08-2016 17:25
asid61
Re: pic: 7.5" tall robot, ready to shoot
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Originally Posted by Greg Woelki
A simpler option might be to use the 90 degree rotated ports version of the cylinder (Bimba offers this for their rear pivot cylinders, I'd imagine other manufacturers do as well).
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10-08-2016 17:32
Chris is me
Re: pic: 7.5" tall robot, ready to shoot
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Originally Posted by asid61
Given that it's already a custom 3.6" stroke cylinder, this is a great option actually.
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10-08-2016 17:38
asid61
Re: pic: 7.5" tall robot, ready to shoot
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Originally Posted by Chris is me
Is it really not possible to go to a standard size here? It can't be that hard to add .1" to the length of your ball joint or something.
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10-08-2016 21:44
frcguy
Re: pic: 7.5" tall robot, ready to shoot
How well would those little read Mecanum wheels on the side of the intake work for directing balls closer to the intake? Do they make a noticeable improvement for ball collection?
10-08-2016 21:48
asid61
Re: pic: 7.5" tall robot, ready to shoot
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Originally Posted by frcguy
How well would those little read Mecanum wheels on the side of the intake work for directing balls closer to the intake? Do they make a noticeable improvement for ball collection?
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10-08-2016 22:05
Golfer4646
Re: pic: 7.5" tall robot, ready to shoot
With this robot, what would your starting configuration be? (Aka, are you able to hold a boulder, while still being within frame perimeter?)
10-08-2016 22:14
asid61
Re: pic: 7.5" tall robot, ready to shoot
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Originally Posted by Golfer4646
With this robot, what would your starting configuration be? (Aka, are you able to hold a boulder, while still being within frame perimeter?)
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10-08-2016 22:40
AdamHeard
Re: pic: 7.5" tall robot, ready to shoot
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Originally Posted by asid61
Because of the tiny packaging and cramped spacers, especially near the shooter/hood, I couldn't make it 3.5" or 4". 3.75" is a custom size anyway, or I would have to use metric. I did try to use a standard size, but the layouts just didn't work out.
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You can definitely make this work with a longer or shorter cylinder, don't forget you don't have to actually use the full travel of a cylinder (and can externally set the travel).
You'd want some mechanical adjustment of shooter position anyway so that you're not remaking parts to tune shots (separate from what you can achieve with software).
10-08-2016 22:50
asid61
Re: pic: 7.5" tall robot, ready to shoot
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Originally Posted by AdamHeard
The custom sizes have poor lead times.
You can definitely make this work with a longer or shorter cylinder, don't forget you don't have to actually use the full travel of a cylinder (and can externally set the travel). |
All of my trials I did with a layout sketch like you did in your RAMP video (great series BTW). I tried with 3.5" but found that I would be unable to flip the hood to the two positions I wanted, and 4" would make it impossible to mount. If I have changed the place where it attached to the hood, it may have been possible to use a shorter cylinder, only moving the cylinder forward caused an interference with something else while folded.
If I had used a custom cylinder extension rod I would have gone a lot farther, but I figured it would be easier to just order the customs.
I wasn't thinking about the turnaround while I was making this. If I had, I probably would have opted to move the hood-side cylinder mount closer to the hood pivot, even though it would have taken extra layout work.
10-08-2016 23:18
Sperkowsky
Re: pic: 7.5" tall robot, ready to shoot
Are there any tensioners on the shooter belt that runs through the tube? If so could I get a look at it?
10-08-2016 23:34
asid61
Re: pic: 7.5" tall robot, ready to shoot
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Originally Posted by Sperkowsky
Are there any tensioners on the shooter belt that runs through the tube? If so could I get a look at it?
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