Go to Post It's cool when good things happen to good people. :) - Rich Kressly [more]
Home
Go Back   Chief Delphi > Technical > Motors
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Closed Thread
Thread Tools Rating: Thread Rating: 3 votes, 5.00 average. Display Modes
  #16   Spotlight this post!  
Unread 19-09-2014, 07:10
Gdeaver Gdeaver is online now
Registered User
FRC #1640
Team Role: Mentor
 
Join Date: Mar 2004
Rookie Year: 2001
Location: West Chester, Pa.
Posts: 1,370
Gdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond repute
Re: Gearing Mini CIMs

This is a link to our web site page with a write up on our surgical tubing shooter with a winch pull back. Some pictures to show what we did. Our shooter is an example of what happens allot in first. It was week 5 with no pull back solution and the pneumatic approach was going no where. Dead end. We took an AM shifter that had been used in a previous year and rigged it up. It's not perfect but the whole system - Roller intake, shooter, swerve worked very well. Looking back, if we had to design this again and had the time, I would have gone with a ball lock release mechanism.
http://wiki.team1640.com/index.php?t...BOT_X_Shooting
  #17   Spotlight this post!  
Unread 19-09-2014, 14:10
Nathan Streeter's Avatar
Nathan Streeter Nathan Streeter is offline
FIRST Fan(atic)
FRC #1519 (Mechanical MAYHEM)
Team Role: Mentor
 
Join Date: Feb 2008
Rookie Year: 2006
Location: Merrimack, NH
Posts: 676
Nathan Streeter has a reputation beyond reputeNathan Streeter has a reputation beyond reputeNathan Streeter has a reputation beyond reputeNathan Streeter has a reputation beyond reputeNathan Streeter has a reputation beyond reputeNathan Streeter has a reputation beyond reputeNathan Streeter has a reputation beyond reputeNathan Streeter has a reputation beyond reputeNathan Streeter has a reputation beyond reputeNathan Streeter has a reputation beyond reputeNathan Streeter has a reputation beyond repute
Re: Gearing Mini CIMs

Perhaps some folks can share their ideas more... but we really liked our launching mechanism...

We used ~100lbf of constant-force springs to provide the power, and used a miniCIM in a modified BallShifter to pull it back, hold, and release. We used a unique gear ratio (somewhere around 10:1, which had good torque but was on the non-optimal side since it was only initially designed for 2/3 the spring force), added a 3/8" ratcheting wrench to provide the stop, packaged it into a basic two-plate with standoffs frame, and put a 1" spool of Spectra cord on the output shaft. This all worked great!

I'm about to leave on vacation for the weekend, but there were some important design constraints in doing the above... for one, the dog shifting mechanism won't be able to retract under that amount of load... we tried... don't bother (unless you have a sense of adventure, like MacGyvering things, and/or have some extra cash to spend). :-)
__________________
"If you want to build a ship, don't drum up men to gather wood, divide the work, or give orders. Instead, teach them to yearn for the vast and endless sea." - Antoine de Saint-Exupery
"The fight is won or lost far away from witnesses - behind the lines, in the gym, and out there on the road, long before I dance under those lights." - Muhammad Ali
"Simplicity is the ultimate sophistication." - Leonardo da Vinci


Student: 2006-2010 (#1519)
Mentor: 2011-Present (#1519)


  #18   Spotlight this post!  
Unread 19-09-2014, 14:16
AdamHeard's Avatar
AdamHeard AdamHeard is offline
Lead Mentor
FRC #0973 (Greybots)
Team Role: Mentor
 
Join Date: Oct 2004
Rookie Year: 2004
Location: Atascadero
Posts: 5,526
AdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond repute
Send a message via AIM to AdamHeard
Re: Gearing Mini CIMs

Quote:
Originally Posted by Gdeaver View Post
Actually you can use the motor to hold the surgical tubing pulled back. That's what we did this year. We used a cim but could have used a mini cim. Used the parts from a Andy Mark shifter and added one more reduction stage. Used a force sensor to measure the pull back force and a PI to hold at about 120 LBS of tension. The holding current was surprisingly low and the motor only gets slightly warm even after extended run times. Only problem is the Andymark dog design has very little contact and the dog and gear wear. They have to be replaced periodically. Benefit of the design is that we can just kill power and the ball is just released with out shooting. At the end of the match the shooter is not in a cocked state. good for safety.
Curious, what force sensor did you use?
  #19   Spotlight this post!  
Unread 19-09-2014, 16:49
Gdeaver Gdeaver is online now
Registered User
FRC #1640
Team Role: Mentor
 
Join Date: Mar 2004
Rookie Year: 2001
Location: West Chester, Pa.
Posts: 1,370
Gdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond reputeGdeaver has a reputation beyond repute
Re: Gearing Mini CIMs

You can search all over but there are not many choices for a amplified and conditioned 5 volt force sensor.
http://www.digikey.com/product-detai...6951-ND/809397

Yes, this was one of the build seasons major crisis. We had both a 3 stage andy mark and a vex pro ball shifter. Looked at both. Choose the andy mark because it could be modified the fastest. Was tested after 1 night's work and we went for it. Looking back the ball shifter is what we should have done but there was no time to devote to it. Make your choices and live with them. Yes, it does take a 1.5 inch pancake at 40 psi to rip the dog out. We replace the dog gear before each competition. I like balls. We also used a ball clutch on our intake roller to prevent RS motor burn out.
  #20   Spotlight this post!  
Unread 19-09-2014, 17:24
Ether's Avatar
Ether Ether is offline
systems engineer (retired)
no team
 
Join Date: Nov 2009
Rookie Year: 1969
Location: US
Posts: 8,125
Ether has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond repute
Re: Gearing Mini CIMs

Quote:
Originally Posted by Gdeaver View Post
it does take a 1.5 inch pancake at 40 psi to rip the dog out. We replace the dog gear before each competition.
Do you cut motor power before disengaging the dog clutch?


  #21   Spotlight this post!  
Unread 20-09-2014, 18:00
wireties's Avatar
wireties wireties is offline
Principal Engineer
AKA: Keith Buchanan
FRC #1296 (Full Metal Jackets)
Team Role: Mentor
 
Join Date: Jan 2006
Rookie Year: 2004
Location: Rockwall, TX
Posts: 1,171
wireties has a reputation beyond reputewireties has a reputation beyond reputewireties has a reputation beyond reputewireties has a reputation beyond reputewireties has a reputation beyond reputewireties has a reputation beyond reputewireties has a reputation beyond reputewireties has a reputation beyond reputewireties has a reputation beyond reputewireties has a reputation beyond reputewireties has a reputation beyond repute
Send a message via AIM to wireties
Re: Gearing Mini CIMs

Quote:
Originally Posted by Gdeaver View Post
Actually you can use the motor to hold the surgical tubing pulled back.
True, of course, but you are wasting power driving around with the motor holding the surgical tubing back. You can gear it so things are easier on the motor but that is a compromise also - it would take longer to pull the tubing back.
__________________
Fast, cheap or working - pick any two!
Closed Thread


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 15:29.

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