Go to Post Fame is a funny thing, you can do nothing and get it, and do everything and get none. For me, it's not fame, but infamy that follows me. - Joe Matt [more]
Home
Go Back   Chief Delphi > Technical > Pneumatics
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Closed Thread
 
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 11-01-2005, 09:13
Fred Hord Fred Hord is offline
Registered User
no team
 
Join Date: Jan 2004
Location: Florida
Posts: 11
Fred Hord is on a distinguished road
Re: Pneumatic Confusion

Quote:
Originally Posted by Cyberguy34000
Pneumatics are something that I thought I had a pretty good idea of how they worked, but as I'm reading more and more of the posts on this form I'm questioning if I know them as well I think I do. I'm considering proposing an arm design at tonight's meeting that involves 3 pneumatic pistons. One for the base, another for the elbow, and the final one for the grabber. As I understood it, pneumatics work by controlling the releasing of pressurized air to manipulate movable pistons which when they become pressurized, expand.

But is the process controllable enough to be used on something that needs a great deal of prison and control, such as a joint in an arm? Can you acurately control the joint of the arm or would it only have one of two extremes? Please help.
Pneumatic cylinders are very controlable with the use of the flow controls in the kit. They control the velocity that the cylinders move at. I would not suggest trying to use them in a situation where you need three or more positions. The first is all the way retracted and the second is all the way extended. Fred Hord
  #2   Spotlight this post!  
Unread 11-01-2005, 12:28
Leo M Leo M is offline
Registered User
#0384 (Tucker Tigers)
 
Join Date: Jun 2001
Location: Richmond, VA
Posts: 70
Leo M is just really niceLeo M is just really niceLeo M is just really niceLeo M is just really niceLeo M is just really nice
Re: Pneumatic Confusion

Lots of options for 3-position, closed-center valves. The hardest part is finding them in 12 VDC. Try Grainger Stock # 2G449, an ARO A312SD-012-D valve, about $114 in my older catalog. Or # 4TR82, about $100.

I didn't see anything in McMaster-Carr, but just did a quick look.

You don't have to use SMC - if they are backordered, go to another vendor (this is just like real engineering life; things you need are always unobtainable).

These valves are great additions to the legal parts - energize one solenoid to extend, energize the other to retract, and de-energize both to hold position.
__________________
Leo M.
  #3   Spotlight this post!  
Unread 13-01-2005, 01:36
Cyberguy34000's Avatar
Cyberguy34000 Cyberguy34000 is offline
Scout-Master
AKA: Chris
FRC #0662 (Rocky Mountain Robotics)
Team Role: Scout
 
Join Date: Jan 2005
Rookie Year: 2004
Location: Colorado Springs
Posts: 410
Cyberguy34000 has a reputation beyond reputeCyberguy34000 has a reputation beyond reputeCyberguy34000 has a reputation beyond reputeCyberguy34000 has a reputation beyond reputeCyberguy34000 has a reputation beyond reputeCyberguy34000 has a reputation beyond reputeCyberguy34000 has a reputation beyond reputeCyberguy34000 has a reputation beyond reputeCyberguy34000 has a reputation beyond reputeCyberguy34000 has a reputation beyond reputeCyberguy34000 has a reputation beyond repute
Send a message via AIM to Cyberguy34000
Re: Pneumatic Confusion

Alrighty, thank you very much people for your help, I had what I needed to make the presentation. Thanx!
__________________

I love deadlines, I love the wooshing sound they make as they fly by. - Douglas Adams

They who would give up an essential liberty for temporary security, deserve neither liberty or security. - Benjamin Franklin

  #4   Spotlight this post!  
Unread 13-01-2005, 02:01
oreocookeee oreocookeee is offline
Critic Extraordinaire
AKA: orie
#0810 (Mechanical Bulls)
Team Role: Leadership
 
Join Date: Jan 2002
Rookie Year: 2001
Location: Smithtown, NY
Posts: 57
oreocookeee is on a distinguished road
Send a message via AIM to oreocookeee
Re: Pneumatic Confusion

cyberguy: i would recommend considering a lead screw for your design. the system would probably be heavier than a piston, but the functionality is very similar. the torque on the arm, or the force of the screw, would be close to if not more than that of a piston. it allows you have any position within its boundaries, and it can easily be encoded with a potentiometer. my team is planing to use one for the lower stage of our arm.

for those with experience with multi-position pistons: how firmly is the piston held at intermediate positions? the only way a normal piston stay rigid is by applying excessive force in one direction, mechanically locking it in place. if the piston is held midway between the extremes, wouldnt it act much like a pneumatic spring, or shock for that matter?
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

Similar Threads
Thread Thread Starter Forum Replies Last Post
pneumatics and joysticks Jared Stofflett Pneumatics 3 24-02-2004 23:56
pneumatics and joysticks Jared Stofflett Programming 1 24-02-2004 17:45
What are pneumatics? Aignam Pneumatics 23 16-10-2002 21:17
pneumatics archiver 2000 1 23-06-2002 22:42
pneumatics? archiver 2001 5 23-06-2002 22:18


All times are GMT -5. The time now is 22:39.

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