Go to Post The sign applause was definately one of the best moments I had ever witnessed at a FIRST event. Who knew silence could be so loud? - Koko Ed [more]
Home
Go Back   Chief Delphi > Technical > Technical Discussion
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Reply
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 02-11-2018, 08:42 PM
pKlopp pKlopp is offline
Registered User
FRC #0100 (The WildHats)
Team Role: Mechanical
 
Join Date: Apr 2017
Rookie Year: 2017
Location: Redwood City, CA
Posts: 59
pKlopp is on a distinguished road
Climbing with elevator

We are coming upon the last week of build season and our robot it CAD is drastically overweight. At this rate we will come out at least 10 lbs over, maybe much more than that. Right now we have a separate climber subsystem and elevator subsystem. The easiest way to come out underweight is completely scrap the climber. Any thoughts on the strategic viability of this? The original thoughts behind climbing with a separate subsystem to the elevator was that we didn't want to tweak our elevator and remove our ability to score on the scale, which is a major part of our strategy. At this point however, Iím skeptical that we are actually risking much of anything by climbing with the elevator. I can see where some of my team members are coming from, eliminating the climber, our most problematic subsystem would free up a bunch of time to finish up fabrication on other subsystems. Our options the way that I see it are, kill the climb, forget about the climber for now and hope we come out enough underweight to bring it to your first competition, or climb with the elevator. In a minute I will post a picture of our elevator bearing setup in CAD. The two side bearings, which take most of the load are mounted on ľ-20s. The other bearings are mounted on a 10-32. To me, this seems robust enough to withstand the forces of a climbing robot, but others on my team have expressed some concern. The elevator itself is made out of 2 x 1 1/16th wall aluminum extrusion.
Reply With Quote
  #2   Spotlight this post!  
Unread 02-11-2018, 09:10 PM
Ethan Pui's Avatar
Ethan Pui Ethan Pui is offline
Registered User
FRC #5663 (Ground Control)
Team Role: Leadership
 
Join Date: Dec 2016
Rookie Year: 2016
Location: Australia
Posts: 23
Ethan Pui is an unknown quantity at this point
Re: Climbing with elevator

The only concern that I would have in terms of having your elevator mech the same as your climber, is if you damaged your bot during climb your main mech will probably be affected resulting in your bot being useless, this can be thought as happening the other way also( if you damaged your elevator you can't climb.)
Reply With Quote
  #3   Spotlight this post!  
Unread 02-11-2018, 09:38 PM
Billfred's Avatar
Billfred Billfred is offline
Eat, Sleep, Break The Streak
AKA: Less Curt Hawkins, More a Paul Heyman Guy
FRC #1293 (Pandamaniacs); FTC #11444 (Garnet Squadron)
Team Role: Mentor
 
Join Date: Feb 2004
Rookie Year: 2004
Location: West Columbia, SC
Posts: 9,188
Billfred has a reputation beyond reputeBillfred has a reputation beyond reputeBillfred has a reputation beyond reputeBillfred has a reputation beyond reputeBillfred has a reputation beyond reputeBillfred has a reputation beyond reputeBillfred has a reputation beyond reputeBillfred has a reputation beyond reputeBillfred has a reputation beyond reputeBillfred has a reputation beyond reputeBillfred has a reputation beyond repute
Re: Climbing with elevator

I don't know the particulars of your design, but if you aren't sure why risk it if you don't have to? Letting the elevator secure a hook that detaches (think velcro) and then gets winched in lets the load go through your cable/rope/strap instead. And while that adds some weight compared to using the elevator, a DeCIMate-to-Toughbox-Micro setup on the winch* should still shave some weight off compared to a full separate climber system.

*Yes, there are alternatives I'm sure you can concoct. Yes, our winch was specced out by someone who used to work at AndyMark. But we didn't trust a dual-775-to-VersaPlanetary arrangement for something with loads this high, and AndyMark doesn't rate the 57 Sport for a DeCIMate. The TB Micro is bigger in two dimensions and heavier, but it's well-characterized and that counts for a lot.
__________________
William "Billfred" Leverette - Gamecock/Jessica Boucher victim/Owner/Director of Bricks 4 Kidz in Columbia, SC.

2004-2006: FRC 1293 (D5 Robotics) - Student, Mentor, Coach
2007-2009: FRC 1618 (Capital Robotics) - Mentor, Coach
2009-2013: FRC 2815 (Los Pollos Locos) - Mentor, Coach - Palmetto '09, Peachtree '11, Palmetto '11, Palmetto '12
2010: FRC 1398 (Keenan Robo-Raiders) - Mentor - Palmetto '10
2014-2016: FRC 4901 (Garnet Squadron) - Co-Founder and Head Bot Coach - Orlando '14, SCRIW '16
2017: FRC 5402 (Iron Kings) - Mentor, Coach
2018-: FRC 1293 (Pandamaniacs) - Mentor

108 events (more than will fit in a ChiefDelphi signature), 15 seasons, over 71,000 miles, and still on a mission from Bob.
Rule #1: Do not die. Rule #2: Be respectful. Rule #3: Be safe. Rule #4: Follow the handbook.
Reply With Quote
  #4   Spotlight this post!  
Unread 02-11-2018, 09:53 PM
mrnoble's Avatar
mrnoble mrnoble is online now
teacher/coach
FRC #1339 (Angelbotics)
Team Role: Coach
 
Join Date: Dec 2008
Rookie Year: 2004
Location: denver, co
Posts: 1,390
mrnoble has a reputation beyond reputemrnoble has a reputation beyond reputemrnoble has a reputation beyond reputemrnoble has a reputation beyond reputemrnoble has a reputation beyond reputemrnoble has a reputation beyond reputemrnoble has a reputation beyond reputemrnoble has a reputation beyond reputemrnoble has a reputation beyond reputemrnoble has a reputation beyond reputemrnoble has a reputation beyond repute
Re: Climbing with elevator

Quote:
Originally Posted by Billfred View Post
I don't know the particulars of your design, but if you aren't sure why risk it if you don't have to? Letting the elevator secure a hook that detaches (think velcro) and then gets winched in lets the load go through your cable/rope/strap instead. And while that adds some weight compared to using the elevator, a DeCIMate-to-Toughbox-Micro setup on the winch* should still shave some weight off compared to a full separate climber system.


*Yes, there are alternatives I'm sure you can concoct. Yes, our winch was specced out by someone who used to work at AndyMark. But we didn't trust a dual-775-to-VersaPlanetary arrangement for something with loads this high, and AndyMark doesn't rate the 57 Sport for a DeCIMate. The TB Micro is bigger in two dimensions and heavier, but it's well-characterized and that counts for a lot.
Billfred, the main issue my team ended up with for the velcroed carabineer idea was keeping the slack cable out of the way before engaging in the climbing winch. We ended up (for now) attaching our climbing hook to our carriage and intake, knowing that the connection point is robust and that loads will travel nearly straight down. We will see if any grand ideas come to light after our week one event, and maybe implement them for week four. I don't know the OP's design at all, but sometimes this idea is the simplest solution.
__________________
http://www.angelbotics.com

Remember why you're doing this.
Reply With Quote
  #5   Spotlight this post!  
Unread 02-11-2018, 10:18 PM
EricH's Avatar
EricH EricH is online now
New year, new team
FRC #1197 (Torbots)
Team Role: Engineer
 
Join Date: Jan 2005
Rookie Year: 2003
Location: SoCal
Posts: 21,398
EricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond repute
Re: Climbing with elevator

A word of caution on the use of Velcro to secure the hook to the elevator:

Yes, it's been used before.

Yes, I've seen some successful implementations.

Yes, I have seen the hook detach from the robot frame and drag all over the field on other implementations. See also: G05 and/or other possible rules violations.


Your setup sounds similar to an old robot I worked on... or one before that that I don't have a photo of. (Thicker aluminum on the pictured bot--1/8" thick channels instead of 1/16".) I would think that you could get by with a large hook bolted to the top of the lift--exact design up to you.
__________________
Past teams:
2003-2007: FRC0330 BeachBots; 2008: FRC1135 Shmoebotics; 2012: FRC4046 Schroedinger's Dragons

"Rockets are tricky..."--Elon Musk


Reply With Quote
  #6   Spotlight this post!  
Unread 02-11-2018, 10:45 PM
pKlopp pKlopp is offline
Registered User
FRC #0100 (The WildHats)
Team Role: Mechanical
 
Join Date: Apr 2017
Rookie Year: 2017
Location: Redwood City, CA
Posts: 59
pKlopp is on a distinguished road
We looked at attaching hooks to the elevator, but we ran into the rope slack issues as mentioned above. Right now what we have is an arm that swings up of the back of our elevator to deliver a velcroed hook to the rung. It’s a robust concept but we need to lose weight and fast.


Sent from my iPhone using Tapatalk
Reply With Quote
  #7   Spotlight this post!  
Unread 02-12-2018, 12:11 AM
EricH's Avatar
EricH EricH is online now
New year, new team
FRC #1197 (Torbots)
Team Role: Engineer
 
Join Date: Jan 2005
Rookie Year: 2003
Location: SoCal
Posts: 21,398
EricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond repute
Re: Climbing with elevator

Quote:
Originally Posted by pKlopp View Post
We looked at attaching hooks to the elevator, but we ran into the rope slack issues as mentioned above. Right now what we have is an arm that swings up of the back of our elevator to deliver a velcroed hook to the rung. It's a robust concept but we need to lose weight and fast.
What about using the elevator itself to climb? Don't release the hook, build it into the elevator.
__________________
Past teams:
2003-2007: FRC0330 BeachBots; 2008: FRC1135 Shmoebotics; 2012: FRC4046 Schroedinger's Dragons

"Rockets are tricky..."--Elon Musk


Reply With Quote
  #8   Spotlight this post!  
Unread 02-12-2018, 07:53 AM
edm918 edm918 is offline
Registered User
FRC #5945 (Absolute Control)
Team Role: Mechanical
 
Join Date: Jan 2017
Rookie Year: 2014
Location: Maryland
Posts: 12
edm918 is an unknown quantity at this point
Re: Climbing with elevator

How heavy is your climber?
Reply With Quote
  #9   Spotlight this post!  
Unread 02-12-2018, 09:43 AM
OwenD's Avatar
OwenD OwenD is offline
Registered User
AKA: Owen Dray
FRC #2067 (Apple Pi)
Team Role: CAD
 
Join Date: Jan 2016
Rookie Year: 2016
Location: Guilford, CT
Posts: 28
OwenD is on a distinguished road
Re: Climbing with elevator

Unless you want a pretty slow lift, you will probably want a two speed gearbox. I do think it is a good idea to reduce weight.
Reply With Quote
  #10   Spotlight this post!  
Unread 02-12-2018, 09:56 AM
Daniel_LaFleur's Avatar
Daniel_LaFleur Daniel_LaFleur is offline
Mad Scientist
AKA: Me
FRC #2040 (DERT)
Team Role: Engineer
 
Join Date: Apr 2005
Rookie Year: 2003
Location: Peoria, IL
Posts: 2,242
Daniel_LaFleur has a reputation beyond reputeDaniel_LaFleur has a reputation beyond reputeDaniel_LaFleur has a reputation beyond reputeDaniel_LaFleur has a reputation beyond reputeDaniel_LaFleur has a reputation beyond reputeDaniel_LaFleur has a reputation beyond reputeDaniel_LaFleur has a reputation beyond reputeDaniel_LaFleur has a reputation beyond reputeDaniel_LaFleur has a reputation beyond reputeDaniel_LaFleur has a reputation beyond reputeDaniel_LaFleur has a reputation beyond repute
Send a message via MSN to Daniel_LaFleur
Re: Climbing with elevator

Quote:
Originally Posted by OwenD View Post
Unless you want a pretty slow lift, you will probably want a two speed gearbox. I do think it is a good idea to reduce weight.
Why a 2 speed gearbox?

You can get a good sub-5 second start-to-finish climb with a single speed gearbox.
__________________
"We are not now that strength which in old days moved earth and heaven; that which we are, we are;
One equal temper of heroic hearts, Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield. "
- Tennyson, Ulysses
Reply With Quote
  #11   Spotlight this post!  
Unread 02-12-2018, 10:00 AM
OwenD's Avatar
OwenD OwenD is offline
Registered User
AKA: Owen Dray
FRC #2067 (Apple Pi)
Team Role: CAD
 
Join Date: Jan 2016
Rookie Year: 2016
Location: Guilford, CT
Posts: 28
OwenD is on a distinguished road
Re: Climbing with elevator

Quote:
Originally Posted by Daniel_LaFleur View Post
Why a 2 speed gearbox?

You can get a good sub-5 second start-to-finish climb with a single speed gearbox.
You can lift the cubes with a much lower ratio compared to climbing, so in order to not limit yourself to only the higher ratio that climbing requires, you would want a two speed. If you are fine with lifting the cubes slower then you can get away with a single speed.
Reply With Quote
  #12   Spotlight this post!  
Unread 02-12-2018, 02:29 PM
s-neff's Avatar
s-neff s-neff is offline
Registered User
AKA: Sam
FRC #0841 (Biomechs)
Team Role: Mentor
 
Join Date: Apr 2016
Rookie Year: 2009
Location: California
Posts: 153
s-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond repute
Re: Climbing with elevator

You can keep independent gearboxes and still mount the hook on the elevator.

Here's one method:

Last year... Did you see how 254 & others took up slack in their climbing ropes?

There would be a ~10-12" section of flat climbing webbing, sewed to a 6"-8" section of flat elastic. When slack, the loop would be pulled together. When taut, the climbing rope would stretch out to full length before taking load.

You could put a hook on your elevator, and run an elastic + climbing webbing system like that to keep your slack out of the way during ordinary operations. Once you're ready to climb, place the hook, deactivate your regular elevator motor & winch up on your climbing gearbox.
You'll still want a thin lexan shield or something to keep it from flapping into your elevator, but it all still sounds a lot lighter than an entire second arm...

If you want to disconnect the hook from the elevator during climbing... consider an active (pneumatically driven) release...

(841 is currently running a 2-speed elevator gearbox with the hope of climbing on our elevator without losing 1-second cube placement. We'll see how it goes.)
__________________
[size="1"]Mentor - Team 841 (2015 - ? )
Mentor - Team 4 (2013 - 2014)
Student - Team 192 (2009 - 2010)
"Remember why you're doing this." -mrnoble/SIZE]
Reply With Quote
  #13   Spotlight this post!  
Unread 02-12-2018, 02:34 PM
JesseK's Avatar
JesseK JesseK is online now
Expert Flybot Crasher
FRC #1885 (ILITE)
Team Role: Mentor
 
Join Date: Mar 2007
Rookie Year: 2005
Location: Reston, VA
Posts: 4,173
JesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond repute
Re: Climbing with elevator

Quote:
Originally Posted by Daniel_LaFleur View Post
Why a 2 speed gearbox?

You can get a good sub-5 second start-to-finish climb with a single speed gearbox.
In high gear we can go bottom-to-top with a cube in (theory) about a second.

In low gear we can hold the robot indefinitely, stalling the 775's at somewhere between 1.5V and 2V.

That is why we chose a 2-speed (2x775's through a decimate to a AM SS) for ours.
__________________
Reply With Quote
  #14   Spotlight this post!  
Unread 02-12-2018, 02:51 PM
s-neff's Avatar
s-neff s-neff is offline
Registered User
AKA: Sam
FRC #0841 (Biomechs)
Team Role: Mentor
 
Join Date: Apr 2016
Rookie Year: 2009
Location: California
Posts: 153
s-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond reputes-neff has a reputation beyond repute
Re: Climbing with elevator

Quote:
Originally Posted by JesseK View Post
In low gear we can hold the robot indefinitely, stalling the 775's at somewhere between 1.5V and 2V.
That'll work great until the robots are disabled at the end of the match... are you putting a mechanical lock somewhere on it too?
__________________
[size="1"]Mentor - Team 841 (2015 - ? )
Mentor - Team 4 (2013 - 2014)
Student - Team 192 (2009 - 2010)
"Remember why you're doing this." -mrnoble/SIZE]
Reply With Quote
  #15   Spotlight this post!  
Unread 02-12-2018, 02:54 PM
JohnFogarty's Avatar
JohnFogarty JohnFogarty is offline
FRC South Region Recap Host on FUN
FRC #1102 (M'Aiken Magic & Team FUN)
Team Role: Mentor
 
Join Date: Aug 2009
Rookie Year: 2006
Location: Augusta, GA
Posts: 1,728
JohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond reputeJohnFogarty has a reputation beyond repute
Re: Climbing with elevator

Quote:
Originally Posted by s-neff View Post
That'll work great until the robots are disabled at the end of the match... are you putting a mechanical lock somewhere on it too?
You don't have to stay above the line after T-0.
__________________
John Fogarty - 12 Years in FIRST
FLL 1102 -> FTC 3864/1102 | FRC 1102 -> FRC 1772 -> FRC 4901 -> FRC 5632 | FTC 11444 -> FRC 1102 | VRC 5817
Head Coach - FRC Team 1102 M'Aiken Magic
"By teaching students the power of STEM, we're M'Aiken Magic happen!"
2010 FTC World Championship Winner - FTC Team 3864 Driver/Captain
Reply With Quote
Reply


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 06:49 PM.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi