Our team has been having a really hard time choosing a mechanism to angle an arm up and down, Yes i know its a silly request but its our second year in FRC and our first year not being a rookie team, our old mentor is gone and now its just us students. Our robot is a wooden frame with an arm at the top that retracts inside of itself,to simplify we are using the climber in a box, the issue is we don’t know how we should angle it up and down. we were thinking of using a motor with a string attached to the arm to lift it up and down, but this makes us violate the lifting and We really need some suggestions that we could do in a matter of 2 weeks. Thanks!
With a competition in 2 weeks and only a wooden frame (that most likely won’t hold up to the rigors of competition), you’ve certainly got your work cut out for you. It might be time to consider rescoping your robot.
Check out this thread about arm design for the basics of how to build something robust enough to not break.
It sounds like y’all could use a lot of help though. I would recommend sending some students into the main FRC discord to get rapid feedback on your design and constraints. Frankly, the odds that you field something remotely competitive (read: able to sufficiently score game pieces) at this point is pretty low, and I would recommend pivoting to a simpler architecture.
I’d take a look here for a quick and robust way to lift an arm.
We use Pneumatic cylinders to actuate up and down, without the actuation it’s pretty much impossible to place anything above the hybrid node. I have seen many teams use belts/chain drive, yet it is quite inefficient.
One of my favorite robots I’ve seen so far is 9180:
Drivetrain, roller, dreams. Finals at CanPac. Anyone can make this robot. First pick of alliance 2. OP, I highly recommend watching their match videos and replicating what they’re doing.
If you’re competing in two weeks, and you don’t have more progress than this I would highly recommend you re-think what your competition goals are.
In the CHS Blacksburg event last week, a historically very good team had their scoring mechanism break into pieces. They finished the event winning the last five matches in a row, with nothing but a robot that could push cones and cubes into the lower goal.
If you take a look at the first chesapeake video archive from last week, find 623 matches. They have a great driver and ended being an alliance captain without a scoring mechanism.
A very basic robot with a well-practiced driver is much more fun at the competition than a barely functioning more complicated robot that can’t really play the game. (In my opinion of course)
Forgive me if I’m missing something, but your team seems to be using an elevator (using a string) that pivots pneumatically. OP is using a telescoping arm, which is a different sort of mechanism entirely.
Correct, angling up and down on a pivot point is what the cylinders is for, our lift is chain driven up and down including a spring and strings. The pivot (angling up and down) is done by the cylinders
A telescoping arm could be mounted onto an elevator of some kind, or even pivoted using some similar method.
having seen this team in person, its very impressive. Not only is it incredibly simple to the point anyone could put it together but its extremely effective at what it does which is be fast and fill the low row with cubes (which in week 1 is more than enough to be good).