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-   -   How Fast Can you Safely Climb? (http://www.chiefdelphi.com/forums/showthread.php?t=153871)

gegozi 18-01-2017 23:09

Re: How Fast Can you Safely Climb?
 
Quote:

Originally Posted by Lireal (Post 1633139)
The issue would be if a team only had a motor keeping the robot up, it would crash to the ground immediately.

It doesn't matter if the robot falls after the timer stops.
The rules say that as long as the button is pressed through time 0 and it is pressed for over 1 second, it will count. I'd therefore recommend that you run your winch a little more than the minimum requirement to make sure that even if it does begin to slip or unravel, the button will still be pressed enough to credit the points.

If you're referring to the robot damage, that could be a serious issue.
I talked about this with my sister and she said to use an airbag-type system to prevent robot damage. I would LOVE to see someone build an airbag-type system that is FRC legal.

Either way, I hope this helps.

matthewdenny 19-01-2017 05:49

Re: How Fast Can you Safely Climb?
 
My back of the envelope calculations tell me a 2.5 second 1-CIM climber at motor max power point is very doable. Half that for 2 CIMs.

Koko Ed 19-01-2017 06:45

Re: How Fast Can you Safely Climb?
 
Quote:

Originally Posted by Richard Wallace (Post 1633119)
^ QFT.

The first time your robot does this, your team will have violated G15-H. Penalties: FOUL; if extended or repeated, then YELLOW CARD; if Head Ref deems that further damage is likely, DISABLED. There had better not be a second time, because if so your team will have violated T03, and will fail most egregiously.*
------------

*See "Bill and Ted's Excellent Adventure."

Team 1815 at GTCR learned this the hard way, last year, when they impacted the wall hard three matches in a row. The head ref told them to fix it after the second time it happened and when it happened a third time he gave them a red card.

JesseK 19-01-2017 09:10

Re: How Fast Can you Safely Climb?
 
Quote:

Originally Posted by Eric Scheuing (Post 1633122)
The answer is yes, but you want to do this as a backup, not as a primary stop feature. I say this as a team that used this method last year, and was having anxiety attacks all season about burning out that motor.

Different anecdote:

The only sensors 1538 added to their bot for the 2015 season were encoders. They used current sensing for limits. Even with all of its complexity, this is what their wiring looked like.

It takes time to develop current-based limits. They don't work if a team decides to try them out for the first time on the robot in week 6.

dirtbikerxz 19-01-2017 09:33

Re: How Fast Can you Safely Climb?
 
Just have the drivers stop pushing the "climb" button, when the bot slams into the touchpad. Since climbers this year (most likely) will only have to be turning in one direction, a simple solution to avoiding having to stall the motors to stay up is just sticking a ratcheting socket wrench on the end of the climber shaft. That should keep the bot from coming back down without having to stall the motors.

MrForbes 19-01-2017 09:40

Re: How Fast Can you Safely Climb?
 
When I read the rules, it appeared that if your robot contacts the touchpad, but then goes back down the rope enough that the touchpad is no longer activated, then you can't get the climbing bonus.

It might be that you want to spend a little time on the control system for your climbing mechanism?

Chris is me 19-01-2017 09:58

Re: How Fast Can you Safely Climb?
 
Quote:

Originally Posted by MrForbes (Post 1633400)
When I read the rules, it appeared that if your robot contacts the touchpad, but then goes back down the rope enough that the touchpad is no longer activated, then you can't get the climbing bonus.

It might be that you want to spend a little time on the control system for your climbing mechanism?

This isn't a universally true statement. You just need to satisfy the two criteria:
  1. Touch the pad for at least 1 continuous second
  2. Touch the pad during the 0.0 second mark on the clock.

I actually can't find anything in the rules that suggests that these two operations have to be done in the same instance of touching the button; I could have missed that though. Point being, if you touch the button at zero seconds, and you've already touched it for 1 second or more beforehand, you don't need to stay up there.

Any number of really simple control system things can ensure you don't immediately fall back down once you touch the button - it could be as simple as a feed-forward gain.

Basel A 19-01-2017 10:09

Re: How Fast Can you Safely Climb?
 
Quote:

Originally Posted by Chris is me (Post 1633411)
This isn't a universally true statement. You just need to satisfy the two criteria:
  1. Touch the pad for at least 1 continuous second
  2. Touch the pad during the 0.0 second mark on the clock.

I actually can't find anything in the rules that suggests that these two operations have to be done in the same instance of touching the button; I could have missed that though. Point being, if you touch the button at zero seconds, and you've already touched it for 1 second or more beforehand, you don't need to stay up there.

Any number of really simple control system things can ensure you don't immediately fall back down once you touch the button - it could be as simple as a feed-forward gain.

That would be a good question for the Q&A. I would anticipate that it does have to be the same instance but as you say, that's not specified.

As for control, the easiest way is to (a) press the touchpad using something springy like a bumper and (b) have something mechanical like a ratchet keeping you from moving downward. This combination means you can stop all power but will still be exerting some small amount of force on the touchpad.

Chris is me 19-01-2017 10:18

Re: How Fast Can you Safely Climb?
 
Quote:

Originally Posted by Basel A (Post 1633416)
That would be a good question for the Q&A. I would anticipate that it does have to be the same instance but as you say, that's not specified.

As for control, the easiest way is to (a) press the touchpad using something springy like a bumper and (b) have something mechanical like a ratchet keeping you from moving downward. This combination means you can stop all power but will still be exerting some small amount of force on the touchpad.

After reading section 3.9 again, it specifies the three criteria to score are evaluated "at the end of the MATCH", which seems to imply that you have to satisfy the T=0 requirement at the same time you satisfy the >1 second requirement.

Eric Scheuing 19-01-2017 10:24

Re: How Fast Can you Safely Climb?
 
Quote:

Originally Posted by Basel A (Post 1633416)
That would be a good question for the Q&A. I would anticipate that it does have to be the same instance but as you say, that's not specified.

I would think so as well, but all I was able to find in the rules was this:

"If a ROBOT causes a dome to illuminate, but disengages from the
TOUCHPAD, the dome turns off and the associated points are removed from the real-time score."

Let's see what the Q&A has to say about this!


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