Hello and welcome to our Robot’s (Kennedy) Update thread. We will be posting on facebook and this thread. Please like our page by searching “2880A Endeavour” on Facebook
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Our hanging design as of now.
Features a locking mechanism powered by rubber bands in a clip design.
https://vexforum.com/attachment.php?attachmentid=7545&stc=1&d=1373297861
Love the drawings!! Drawings this detailed are more impressive than cad software. But it’s always safe to use CAD to check your work
Thanks Draco. The funny part is that it was done all free hand by me!
Hanging Hook is almost finished. Adding fourth tier of Linear Lift, and painting the parts. Please Support Us by Liking our Facebook page at 2880A Endeavour.https://vexforum.com/attachment.php?attachmentid=7546&stc=1&d=1373495095
as this thing is developing, i have reminiscences of 1103
We gained knowledge of Mr. Wade’s robot by observing and documenting the steps where he left off. We are planning to move with a 6:1 Ratio for Speed on the wheels, hang in 3 seconds (Including shooting up to the bar), and be 2x as fast as Curahee. I like to say we are picking up where he left off.
I hope your not using 4" wheels :eek: I would love to see you be able to pull it off, sounds like you have something awesome planned out.
Since we will likely see you in New Orleans and Galveston don’t go over achieving 
We do indeed! Maybe well talk a little strategy later on with you being a scissor and all. But we are hoping to Overacheive a little, due to our reputation in Galveston and the jeapordy of our Team being shutdown. (Our school is more focused on Sports and sees hardly any future in Robotics) We hope to see you guys soon.
P.S. Don’t Run with scissors in your hand! 
6:1 on 4" wheels? You would need a 10 motor drivetrain to even come close to enough acceleration to make that feasible. A 4 motor drivetrain struggles with 3:1, to the point we decided to scale our initial goals down. While your robot may still move at higher gear ratios, its acceleration will be so little that it will be virtually useless. You will take so long reaching maximum speed, it’s not worth getting there. I don’t even know if there’s enough room on the field.
How heavy is your final build going to be? You end up using a LOT of metal, chain and gears for a linear lift. I would be amazed if you can hoist what I assume will be an 11-14 pound robot with less than four motors at 5:1. Ours at a presumed 8 pounds is still barely going up with 4 motors at 3:1.
Have you done the math for the physics behind this design yet?
I never said it would have Great Acceleration. And I understand there would be no point without good acceleration. I personally have had experience with low acceleration drivetrains and are fully aware of the physics behind it.
But lets be honest here, of it had enough room to accelerate to MAX speed, then it would fly over the bump, possibly lift the front part, and cause tipping. If my math is right, full speed is somewhere around the 11-15 mph range.
We are making it all mostly out of Aluminum, and expect it to be around the 7 lbs range
WE WILL ACHEIVE THIS!!! MWAHHAHAH
Interesting ideas, but I see many potential problems (Sorry to be the pessimist )
First off, a linear lift suffers ALOT of friction issues, especially with 4 stages. I would be very cautious of how you build and approach this. Also, linear lifts suffers from a lack of reach, which with only two goals, might be something you’d want to think about.
Another thing is that there is absolutely no reason to have or even try for a 6:1 drive (except for fun). If you know you won’t have good acceleration, your just stressing your motors WAY more then you have to. If your really want to go fast, try a 3:1 at most, which I think is to fast to actually control.
Lastly, since you seem to be in a “1103” mindset, I’m guessing your going with a claw. I’d warn you that a claw is probably the least efficient intake possible for toss up (for bucky balls atleast).
Also, why do you need a latch on the hanging?
Isn’t that sad 
We have not even been able to give robotics kits to a couple of local school districts (really). I bet they would love some football gear though. I suppose if we are going to devolve into a 3rd world country we better be tough. China has 5 times our population, and more than 10 times the STEM graduates. I grew up listening to my parents telling me to clean my plate because there were children starving in China, I wonder if they will be telling their grandchildren the same thing about the hungry kids in the U.S.?
I don’t see the 6:1 ratio working well unless maybe you go with the 2.75" omni wheels, even just a lightweight base would stress the motors too much. The thought of a pushing match would not be pretty either, your robot would be pretty defenseless there without a braking mechanism. But then again knowing how intelligent you both are I expect you will have something that works well by the time the season starts.
Dang…
Like everyone said, that’s a very high ratio. Not to mention, the need for combination gearing will reduce power efficiency and increase friction. Unlike round up, toss up is quite crowded, so I would recommend strafing away (pun was totally intended XD) from ratios past 2:1 on 4 inches. Especially if you don’t exploit autonomous
Plus going up in 3 seconds seems pretty difficult. Unless of course, your only planning to go above the field perimeter and lock at that height. Were u planning on using pneumatic and elastic assists?
As for the claw, I’m quite curious of it’s efficiency. It would be cool if you had a claw that teamed with the linear lift to accumulate 3 balls. Comine that with (I’m assuming) de-scoring and you have a very powerful system. Of course you can take the scoop approach, but that version may be harder to control when de-scoing
Your math is correct, you will be just a touch over 11mph or 16’8" per second which is approximately 120mph scaled speed. If you were able to achieve this you would have to be able to go from 0 to 11mph in 0.716 seconds which is muscle car acceleration, and at that point you would have hit the wall. This might be a great idea for a project robot, but not for a robot playing on a 12’ field.
Well thanks for ruining my dreams guys gosh.
Nah, I’m just kidding, we redesigned and thought about our drivetrain, and decided to go with a more 3:1 ratio.
And we are not building a Claw; for the buckyballs at least. Well be posting our intakes on this page and on facebook.
We also have done the math on our 3 second hang time. It will be supported by elastics and be triggered by a single acting piston.
Thanks for the input,
3:1 is pushing it, but not impossible. That would travel the 12’ field in just under 1-1/2 seconds (on paper) more like 2-1/2 seconds with acceleration considered which is scary fast. I would think a very light robot and 6-8 motor base would be needed to do it dependably.
We actually tested a bunch of gear ratios earlier. I can save you (and everyone else) the trouble.
1:1.6 (High Speed Internal) is very stable. But everyone knows that.
2:1 is good with 4 motors. We’re running a Mech base with each wheel geared separately, and it’s working well. This is most likely what we will end up using all season.
2.4:1 is iffy with 4 motors. One of our subteams achieved this with 1.6 internal, 18:12 toothed sprockets. The acceleration goes down every time you increase the gear ratio, as I’m sure you know, so if you’re doing a lot of short movements (common during autonomous), you’re may end up going slower than someone who has a slower top speed, but a higher acceleration. We built it on one of our test bases, and they are currently looking into it. I don’t believe they have tested it on the bump, but the 12" sprocket which is physically attached to the axle with the wheel on it doesn’t touch the ground. The problem that you’re going to have is the 18 tooth sprocket. When you build your sprockets to connect on a 2x2x35 Aluminum Angle, it appears as though it would hit the bump. I don’t have the field at home, so I can’t actually confirm or deny my assumption. Just giving you fair warning.
3:1 takes at least 6 motors. With 4 motors, it accelerates super slow, and eventually craps out after driving 2/3 of the way across the field. You can’t even turn. Don’t waste your time. As far as I know, you can’t use a 6 motor drive with Mecanum or X-Drive, either, so you loose out on strafing if you decide to go that fast. It’s the reason we opted not to do it.
All of these were tested with an 18" wheel base, an aluminum frame made with 4 Angles and 2 C-Channels. 4" wheels, one battery, an LCD screen and a gyroscope. Adding on extra mechanisms will obviously increase the mass and weight of the robot, decreasing acceleration further.
We plan on it!
Lets try and be a little bit more optimistic about some of our ideas by the way. Although some of them may seem impossible, were up to the challenge. And now that I look at it, 6:1 is EXTREMELY unreliable.
We are aware of all of our risks, so try to ENcourage us, not DIScourage us.
Afterall, well probably all be at worlds, and I don’t like the awkwardness of tension!
Hey, man. Knock yourself out. I’m just telling you what we already did. No sense in withholding information when it can help people.