Extendable Arm/Hanger Subsystem? What works best?

[Anthony Galea]

Originally Posted by TheSousaLife

If you are hoping to go to big big things, such as world, I'd imagine you would want to climb. An extra 35 points at the end of a match would be absolutely mandatory. Now, I looked into a folding telescoping lift bar, it layed flat so it could get under the low bar. you would need some pistons. You COULD go the pneumatic route if you wish. But Personally I'd stick with electrically telescoping!

It's not 35 points, in reality, when you take in to account challenging, its only worth 10 points. Scaling can definitely be ignored and still have your team make it to Champs. A great example is 2013. Challenging is like a 10 point hang then, and scaling is a 30 point climb. Unless you can do it very quickly, it's not worth it, especially considering that in that time, you could be getting more crossing and high goal points. In 2013, you could outscore a 30 point climb by doing 2 cycles and a 10 point hang. In 2016, I expect that the only way a scaler will be playing on Einstein is if they have a last second climber like 67 in 2010, or if they can very quickly do it in less than 3 seconds.

[Justin Montois]

Originally Posted by 3175student17

I expect that the only way a scaler will be playing on Einstein is if they have a last second climber like 67 in 2010, or if they can very quickly do it in less than 3 seconds.

I suspect 5/6 robots on Einstein will scale every match and do so as you said, in 3 seconds or less. You have to think that if 254 could climb the pyramid in 2013 in 6.4 seconds, a much more difficult challenge, then I have to believe that teams that plan to compete for a world championship will have sub 3 second climbs.

Further, If you're saying the team is already on the batter ready to climb. From the time that team triggers their climb to fully scaled I think you will see around 1 second.

[matthewdenny]

For those who were wondering, like me, (heres my back of an envelope calculations)

140 Lb robot = 622N
climbing ~1m in 1 sec = 622 watts.
1 CIM = 337 watts
You could climb in 1 sec with 2 CIMs, but it would be close and your extension to get the bar in the first place would have to be nearly instant.

[Kevin Leonard]

A few things to the OP first/;
A climber is not necessary to be good this year. There will be dozens of regionals won without a single climber on the winning alliance.
2) Both an offensive strategy up front shooting boulders and a strategy that revolves around being a good breacher that scores low goals and feeds balls can be successful at a regional level.

Now if you still want to climb, there are some references to look at in 2010 and 2013. Additionally, if you skip the low bar, the challenge of climbing becomes much, much easier.

The challenge of climbing is two things:
1) reaching the bar, and
2) pulling your robot up

Reaching the bar can be done in a bunch of ways, including arms and elevators, some of which can be spring-loaded upwards for simplicity's sake.

Pulling your robot up can be done in a few ways, but I think the simplest is to have a strap with a hook attached that you winch down to your robot.

Something to look up:
3467 2013 climbed the pyramid by having their arm automatically spring up with torsion springs, then winching it back down with a strap.

[pilum40]

Originally Posted by Kevin Leonard

A few things to the OP first/;
A climber is not necessary to be good this year. There will be dozens of regionals won without a single climber on the winning alliance.
2) Both an offensive strategy up front shooting boulders and a strategy that revolves around being a good breacher that scores low goals and feeds balls can be successful at a regional level.

Now if you still want to climb, there are some references to look at in 2010 and 2013. Additionally, if you skip the low bar, the challenge of climbing becomes much, much easier.

The challenge of climbing is two things:
1) reaching the bar, and
2) pulling your robot up

Reaching the bar can be done in a bunch of ways, including arms and elevators, some of which can be spring-loaded upwards for simplicity's sake.

Pulling your robot up can be done in a few ways, but I think the simplest is to have a strap with a hook attached that you winch down to your robot.

Something to look up:
3467 2013 climbed the pyramid by having their arm automatically spring up with torsion springs, then winching it back down with a strap.

ok...i'm having my team rtfm again. They told me they could not use springs since it was a source of stored energy. Haha...I'm a dullard aren't I? Thanks for the info so far.

[pfreivald]

Yeah, springs are totally allowed.

Consider the possibility that whatever pulls you up doesn't have to be whatever puts the hook(s) on the bar.

[GreyingJay]

Originally Posted by pilum40

ok...i'm having my team rtfm again. They told me they could not use springs since it was a source of stored energy. Haha...I'm a dullard aren't I? Thanks for the info so far.

Have a look at R35.

[JesseK]

Originally Posted by matthewdenny

For those who were wondering, like me, (heres my back of an envelope calculations)

140 Lb robot = 622N
climbing ~1m in 1 sec = 622 watts.
1 CIM = 337 watts
You could climb in 1 sec with 2 CIMs, but it would be close and your extension to get the bar in the first place would have to be nearly instant.

In the last 20 seconds you can drive around the opponent's courtyard fully extended, regardless of whether you're on the batter or not. So 17 second of extending while driving around still scoring, plus 3 seconds for the lift itself.

Supposing the 40A breakers can handle the over-current match-to-match attached is how it's potentially done in under 1 second. Of course, the 80% gearbox efficiency doesn't account for the winch and any associated pulley inefficiency. I also divide JVN's current draw per motor by the efficiency just as a rough estimate of how much extra current is pulled due to these inefficiencies.

This particular setup would also need anti-backdrive.