OCCRA
Go to Post I wanted to make an epoxy/carbon fiber/fiberglass arm for our 'bot, but I was outvoted by conservative teenagers. Oh well... - Rick TYler [more]
Home
Go Back   Chief Delphi > ChiefDelphi.com Website > Extra 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 09-10-2017, 07:27 PM
samthesnake's Avatar
samthesnake samthesnake is offline
SamD4256
AKA: Sam Dare
FRC #4256 (Cyborg Cats)
Team Role: Leadership
 
Join Date: Apr 2015
Rookie Year: 2015
Location: St. Louis, Mo
Posts: 100
samthesnake will become famous soon enoughsamthesnake will become famous soon enough
pic: Cyborg Swerve 9.0

Reply With Quote
  #2   Spotlight this post!  
Unread 09-10-2017, 07:33 PM
Chak Chak is offline
Registered User
AKA: Thomas
FRC #4159 (Cardinalbotics)
Team Role: Alumni
 
Join Date: May 2015
Rookie Year: 2014
Location: Evanston, Illinois
Posts: 342
Chak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond repute
Re: pic: Cyborg Swerve 9.0

  • Why belts?
  • Are you sure you have sufficient belt wrap on the pulley between the 775pros, if you're using a single belt for the whole thing?
  • What are you planning for the encoders?
  • Do you plan to 3D print the rotating part? (the one with the wheel inside, I call it the "caster") I'm guessing based on the fillets on the part. If you are, it seems like there are several ways to print it stronger.
  • Why stick with hex shaft for dead axle? Seems like you can save a marginal amount of weight by using circular shaft.
  • Can you post a better picture of the bearing setup?

Thanks for sharing your design!
__________________
Reply With Quote
  #3   Spotlight this post!  
Unread 09-10-2017, 10:02 PM
samthesnake's Avatar
samthesnake samthesnake is offline
SamD4256
AKA: Sam Dare
FRC #4256 (Cyborg Cats)
Team Role: Leadership
 
Join Date: Apr 2015
Rookie Year: 2015
Location: St. Louis, Mo
Posts: 100
samthesnake will become famous soon enoughsamthesnake will become famous soon enough
Re: pic: Cyborg Swerve 9.0

Quote:
Originally Posted by Chak View Post
  • Why belts?
  • Are you sure you have sufficient belt wrap on the pulley between the 775pros, if you're using a single belt for the whole thing?
  • What are you planning for the encoders?
  • Do you plan to 3D print the rotating part? (the one with the wheel inside, I call it the "caster") I'm guessing based on the fillets on the part. If you are, it seems like there are several ways to print it stronger.
  • Why stick with hex shaft for dead axle? Seems like you can save a marginal amount of weight by using circular shaft.
  • Can you post a better picture of the bearing setup?

Thanks for sharing your design!
1. The module was wanted to be longer and not a square in order to potentially fit a larger intake or similar mech. Gears needed would have been overly bulky and awkward
2. Not sure your meaning. There is space between the two pulleys both on top and on bottom, if that is what you mean
3. Versaplanetary integrated encoder on a 1:1 pulley ratio a la Stryke Force. Also a backup hall effect sensor I do not have modeled
4. We may end up making it three pieces bolted together like we did last year. I have not consulted my 3D printing expert yet, nor have we decided what printer we are going to purchase
5. We have a bunch of hex stock and hex bearings, but I guess I could have slimmed the wheel down a bit more and used a smaller shaft, you are right
6. Like this except smaller. It surprisingly worked super well last year for us.

Thanks for the questions. Like I said it will look better once I mount it to a frame and bellypan.
__________________
"Perfection is not attainable, but if we chase perfection we can catch excellence." - Vince Lombardi

2015 - ? FRC Team 4256, Cyborg Cats

CAD and Strategy lead, drive coach
Reply With Quote
  #4   Spotlight this post!  
Unread 09-10-2017, 10:19 PM
Chak Chak is offline
Registered User
AKA: Thomas
FRC #4159 (Cardinalbotics)
Team Role: Alumni
 
Join Date: May 2015
Rookie Year: 2014
Location: Evanston, Illinois
Posts: 342
Chak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond reputeChak has a reputation beyond repute
Re: pic: Cyborg Swerve 9.0

Quote:
Originally Posted by samthesnake View Post
2. Not sure your meaning. There is space between the two pulleys both on top and on bottom, if that is what you mean
I meant for the pulleys that make up the first stage from the 775pros.
__________________
Reply With Quote
  #5   Spotlight this post!  
Unread 09-10-2017, 11:30 PM
samthesnake's Avatar
samthesnake samthesnake is offline
SamD4256
AKA: Sam Dare
FRC #4256 (Cyborg Cats)
Team Role: Leadership
 
Join Date: Apr 2015
Rookie Year: 2015
Location: St. Louis, Mo
Posts: 100
samthesnake will become famous soon enoughsamthesnake will become famous soon enough
Re: pic: Cyborg Swerve 9.0

Yes I am sure
__________________
"Perfection is not attainable, but if we chase perfection we can catch excellence." - Vince Lombardi

2015 - ? FRC Team 4256, Cyborg Cats

CAD and Strategy lead, drive coach
Reply With Quote
  #6   Spotlight this post!  
Unread 09-11-2017, 12:37 AM
marcusbernstein's Avatar
marcusbernstein marcusbernstein is online now
Baseball hat kid
AKA: Marcus Bernstein
FRC #1836 (Milkenknights)
Team Role: Team Spirit / Cheering
 
Join Date: Dec 2014
Rookie Year: 2013
Location: Los Angeles
Posts: 289
marcusbernstein has a reputation beyond reputemarcusbernstein has a reputation beyond reputemarcusbernstein has a reputation beyond reputemarcusbernstein has a reputation beyond reputemarcusbernstein has a reputation beyond reputemarcusbernstein has a reputation beyond reputemarcusbernstein has a reputation beyond reputemarcusbernstein has a reputation beyond reputemarcusbernstein has a reputation beyond reputemarcusbernstein has a reputation beyond reputemarcusbernstein has a reputation beyond repute
Re: pic: Cyborg Swerve 9.0

Chak is talking specifically about the belt's wrap around the pulleys. To make sure the belt doesn't skip (among other things above my paygrade), it's important to make sure the belt has sufficient wrap around pulleys, especially those as small as 12t like the one you've used. If you want to understand wrap, think about how many pulley teeth the belt is contacting at once. The more teeth the belt is contacting, the better spread the load is and the better engaged the belt is, making the mechanism much less prone to skipping.
__________________
Here are some quotes that drive me and my team to be successful: (some are mine, some are borrowed, and the list will continue to grow)

"Once you've concluded that it isn't a code problem, it isn't an electrical problem, and it isn't a mechanical problem, after all that blaming you now have a culture problem."
"Precedence is no excuse for being wrong."
"Aesthetics are great, but not at the expense of functionality."
"An entire team rallied around a potentially wrong decision is better than half a team rallied around the right one. And if that potentially wrong decision ends up being the right one, that unified team will be successful."

My views do not necessarily represent the views of my team or any other groups I am affiliated with.
Reply With Quote
  #7   Spotlight this post!  
Unread 09-11-2017, 01:17 AM
samthesnake's Avatar
samthesnake samthesnake is offline
SamD4256
AKA: Sam Dare
FRC #4256 (Cyborg Cats)
Team Role: Leadership
 
Join Date: Apr 2015
Rookie Year: 2015
Location: St. Louis, Mo
Posts: 100
samthesnake will become famous soon enoughsamthesnake will become famous soon enough
Re: pic: Cyborg Swerve 9.0

Quote:
Originally Posted by marcusbernstein View Post
Chak is talking specifically about the belt's wrap around the pulleys. To make sure the belt doesn't skip (among other things above my paygrade), it's important to make sure the belt has sufficient wrap around pulleys, especially those as small as 12t like the one you've used. If you want to understand wrap, think about how many pulley teeth the belt is contacting at once. The more teeth the belt is contacting, the better spread the load is and the better engaged the belt is, making the mechanism much less prone to skipping.
I did think about this. There is a 3/8 hex shaft pressed onto the 775 and an 18 tooth pulley instead of the 12 tooth pinion pulley. The pinion pulley is out of stock constantly, so I went with a larger pulley for that and to get more teeth in contact with the belt.
__________________
"Perfection is not attainable, but if we chase perfection we can catch excellence." - Vince Lombardi

2015 - ? FRC Team 4256, Cyborg Cats

CAD and Strategy lead, drive coach
Reply With Quote
  #8   Spotlight this post!  
Unread 09-11-2017, 02:02 AM
asid61's Avatar
asid61 asid61 is online now
Design Simple
AKA: Anand Rajamani
FRC #1072 (Harker Robotics)
Team Role: Mentor
 
Join Date: Jan 2014
Rookie Year: 2013
Location: Cupertino, CA
Posts: 2,600
asid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond reputeasid61 has a reputation beyond repute
Re: pic: Cyborg Swerve 9.0

Quote:
Originally Posted by samthesnake View Post
4. We may end up making it three pieces bolted together like we did last year. I have not consulted my 3D printing expert yet, nor have we decided what printer we are going to purchase
If you have yet to even purchase a printer, don't rely on 3D printed parts coming out correctly unless it's medium-high end like an Ultimaker or Markforged.

What free speed are you geared for? With a single 775 you're looking at more risk.

Lazy susans are liable to blow up spectacularly. The one you linked seems more robust than most though so you may be ok.
__________________
Team 1072 2017-present
Team 299 2017
Team 115 2013-2016



Reply With Quote
  #9   Spotlight this post!  
Unread 09-11-2017, 01:11 PM
samthesnake's Avatar
samthesnake samthesnake is offline
SamD4256
AKA: Sam Dare
FRC #4256 (Cyborg Cats)
Team Role: Leadership
 
Join Date: Apr 2015
Rookie Year: 2015
Location: St. Louis, Mo
Posts: 100
samthesnake will become famous soon enoughsamthesnake will become famous soon enough
Re: pic: Cyborg Swerve 9.0

Quote:
Originally Posted by asid61 View Post
If you have yet to even purchase a printer, don't rely on 3D printed parts coming out correctly unless it's medium-high end like an Ultimaker or Markforged.

What free speed are you geared for? With a single 775 you're looking at more risk.

Lazy susans are liable to blow up spectacularly. The one you linked seems more robust than most though so you may be ok.
We are just deciding between an Ultimaker and a Markforged.

14.5ish free speed - we may end up making this slower but this is about the fastest it will be.

We had no problems with that lazy susan last year. We did have problems with a poorly made McMaster one with a different design.
__________________
"Perfection is not attainable, but if we chase perfection we can catch excellence." - Vince Lombardi

2015 - ? FRC Team 4256, Cyborg Cats

CAD and Strategy lead, drive coach
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 10:44 PM.

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


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi