Rookie team in need of scaling advice

Our rookie team has achieved most of our conservative goals for functionality and we would like to try to scale the tower. However, we have ZERO experience with scaling (or any of this for that matter) and the student & mentor ideas are all over the place. One kid even suggested we fire a grappling hook Batman style up to the bar.

From what I’ve seen on CD, everyone seems to be using a winch. One of our mentors wants to use a scissor lift with an actuator (we have a 12" Dart) but the vibe I’ve gotten from reading threads on here regarding scissor lifts is akin to the old lady in “Princess Bride” that yells “BOOOOOO” in the courtyard. Why is that? Do they fail often?

How do most teams do this? How exactly do we use a winch? Where should the winch be with regards to the center of mass on the robot? What are the most common failures when scaling?

Basically, we would love any advice, ideas, telescoping tubes, extending arms, scissor lifts, CAD for all of the above, or whatever else you think might help us achieve the (nearly) impossible considering we have a low-bar capable robot that only stands about 14.5" tall.

Thanks in advance not only for the advice, but all of the other epic threads we’ve been devouring as we laugh, argue, build, and clean metal shavings out of our hair each night.

Eloquent example by the way. Our team is in a similar position as you: we have a low bar robot that is attempting to scale. Now I don’t know what the rest of your robot looks like, but what our team is doing is using a simple arm to lift a hook attached to a tether up to the bar and using a motor to “reel” in the hook. As far as a winch/ratcheting system, we are using a good old ratchet strap to ensure that the robot does crash down on the floor after the end of the match.

Of course this is an idea, but my advice to you (us being only a third year team and the memory of rookie year fresh in my head) is really make sure all of your other systems work perfectly before trying to tackle a scaler. If anything, make the scaler your post-build season project and bring it in to your competition and attach it there. The important hig is to perfect what you already have in your robot and practice driving.

Just my advice :slight_smile:

We’re an experienced team, and we have no interest in scaling. I’m sure we’re missing out on a lot of fun, but we want to try to get the robot to play the game…then, maybe, we’ll have time to think about the fun of scaling.

That’s my advice.

Scissor lifts are difficult and prone to breakage is the problem. Whenever it is possible to use a different style of lifter, I would do so.

However, scissor lifts are pretty good under a certain set of circumstances- if you need to achieve a lot of extension, but retract to a very small height.

Now, the reason most teams are using winches is because once you lift your robot up- you need to stay up.
I would expect that if you were to lift yourself up with a DART, it would backdrive as soon as the match ended, and you’d end up below the climb level. I could be wrong, however, so don’t necessarily take my word as gospel.

Some ideas I would check out if I were you are the WCP 2016 MCC: http://www.wcproducts.net/mcc2016/

They use a telescoping arm and have quite a bit of documentation on how you can do the same.

Additionally, I don’t know whether or not your team has decided to go under the low bar, but if you didn’t, then climbing is pretty easy, as you can start at 54" tall and you need to reach up to 76" to climb.

If you have any questions or anything, feel free to PM me or ask more questions in this thread.

Take all the time and effort you would put into a climber, and put it into practice and improvements. Drive the heck out of your bot and break stuff. It’s easier to break and fix now than it will be at competition.

I like to think about it in terms of effort required per point. Climbing is hard and is only worth a net gain of 10 points. Practicing with your robot and getting as many hours as you can on it is much easier and has much more points potential.

I agree and disagree with everyone else on this thread. Yes I don’t think that for a rookie a climb is necessary or even that time efficient when you guys could be working on your shooter. On the other hand for the non rookie teams on this that think that a climb is not necessary to have a bot that people will want once you get to high level regionals and St. Louis…I completely disagree.

The WCP design is good to look at because it is one of the designs that deals with the most difficult part of scaling this year: Staying within your frame perimeter. If your robot tips it has to tip tail up toward the tower (and not too much) or you will quickly be out of your frame perimeter.

We have had some very successful climbing bots (in particular in 2004 and 2010) in the past, but put scaling at the bottom of our priority list this year because of its relative difficulty and relatively low point value. That said, if you have achieved most of your other goals there is no reason not to try to build a scaling device. It does not have to interfere with practice and other development. In 2010 we got an inexpensive manual winch from Lowes and took off the ratchet and sprocket. We welded the sprocket onto our winch spool (but you could use the spool from a winch and bolt on a hub) and attached the ratchet with a spring. Simple and effective.

We’re thinking along these lines. The GDC probably should have put more points on the line (like it should have in 2013 with the pyramid climb) if they wanted it to be more central. It is MUCH more important that you develop a reliable means of challenging the castle at the end–and that’s more difficult than you might think!

Kind of offtopic, but we recently had an argument about exactly that with my team. I argued that the gain was 10 points1, but my teammate argued that it was 15 points2.

1: The game reveal clearly suggests that the 5 point bonus from challenging a tower is removed when you scale it, and the whole sum becomes 15 points(5 is crossed out and 15 takes its place). However:
2: As far as I can see the game manual only has a table(page 3 of the manual) which says that challenging is worth 5 points, and scaling is worth 15. It says nothing about the scaling bonus negating the challenging bonus.

Which one is correct? Can you provide sources?

Here’s the part of the video that shows 5 getting replaced by 15.
http://i.imgur.com/ra6FFJ1.png

3.1.4 THE TOWER

A ROBOT has CHALLENGED the TOWER if, at the conclusion of the MATCH, the ROBOT is fully
supported by the TOWER, but hasn’t met the criteria for SCALING the TOWER.

Glossary:

CHALLENGE an act performed by a ROBOT, such that at the conclusion of the MATCH, the ROBOT
is fully supported by the TOWER, but hasn’t met the criteria for SCALING the TOWER

Once you’ve scaled, you’re no longer challenging. Thus, you can’t get points for both.

You get 5 points for challenging, and 15 points for climbing. The main debate earlier on CD was about whether or not you get TWENTY points for climbing, adding the two scores (which was easily proven false).

The 10pt thing comes in when you subtract the 5 you could get for challenging.

To be fair, many of the 3rd picks at competitions may want to scale for the extra points (the first 2 robots will be scoring the most anyway), and if you’ve already finished your main goals, why not start prototyping now? There are plenty of ways to start on a climber while the drivers get practice, and you can always add it at your competition (providing you stay under the withholding allowance).

For our team at least, if it came down to a 3rd robot breaker and a 3rd robot that breaks a little slower but climbs, I would take the second option. Because the first 2 robots may be making cycles to shoot, they will naturally break several of the defenses anyway, leaving only one or two tricky defenses like the drawbridge to deal with. A 3rd bot can break those quickly before moving to play defense (or just play defense until the endgame).

Ultimately it depends on what you think others’ strategies will be.

Thank you for the responses.

We are slowing our roll with regards to climbing right now due to just how hard all of this is, but haven’t ruled out a “moonshot” attempt to get something together under 30lbs. after the bag date that we can add on later.

Speaking of difficult, my goodness are the Dart actuators difficult to get working properly. Missing magnets for the Hall sensors, no instructions for the Hall effect, weak collars, bad fit for the leads/shaft, weird software interactions, and one of the adult mentors taking apart the best one we’d already assembled to see how it worked so he could build another (not easy) have all led to a cornucopia of frustration with the Darts.

It is truly a shame that the Firgelli actuators (assembled, half the price, much lighter & smaller, just as much strength) are illegal.

Firgellis aren’t illegal. However, their MOTORS are. So if you can retrofit an FRC-legal motor to one, go for it.

Sorry. Meant to say Firgelli motors (and limit switches.)

We are going to try to stay in our lane, practice shooting & defenses, and try to do a few things as well as we can. Much respect to all of you grizzled vets out there. This is hard.

Not enough time left for us to take apart a beautifully made actuator, maybe put a Bag motor on it that works, maybe not lose any shaft keys, collars, etc. and maybe have it actuate properly.