Go to Post just remember, with power comes responsibility. - Mike Ciance [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

 
View Poll Results: pneumatic motors or other for your arm?
motors 64 85.33%
pneumatics 35 46.67%
other 4 5.33%
Multiple Choice Poll. Voters: 75. You may not vote on this poll

Closed Thread
Thread Tools Rate Thread Display Modes
  #31   Spotlight this post!  
Unread 27-01-2005, 01:14
ngreen ngreen is offline
Registered User
AKA: Nelson Green
FRC #1108 (Panther Robotics)
Team Role: Mentor
 
Join Date: Jan 2003
Rookie Year: 2002
Location: Paola, KS
Posts: 821
ngreen has a brilliant futurengreen has a brilliant futurengreen has a brilliant futurengreen has a brilliant futurengreen has a brilliant futurengreen has a brilliant futurengreen has a brilliant futurengreen has a brilliant futurengreen has a brilliant futurengreen has a brilliant futurengreen has a brilliant future
Re: arm design

Quote:
Originally Posted by Andrew Schuetze
To be able to use the metered exhaust will likely require a human touch that an auto program cannot handle consistantly.
I agree with you generally. But it also depends greatly on a the complexity of your movements. In most cases using pneumatics that stop midstroke are similiar to dead reckoning programming. With adjustments and fine tuning you can get good results for simple, broad movements. But for complex, precise movement you are generally out of luck.

An example of this was my teams 2003 robot. We had two cyclinder lifting our stacker. As part of our autonomous we would lift our stacker part way up. It came to the same position almost everytime. But it wouldn't work well it if had to be precise.

This is where some design comes in. IF you design a robot that is able to pick up tetras with broad movements, you would likely be able to tune a program to do it in automounous (thinking about things like air pressure, piston speed, what the tetra weight will do). If it must be precise in it's movements (move two inches, then one inche, and so on) it will likely be hard for autonomous and equally so for the driver's and any programming in user mode.
  #32   Spotlight this post!  
Unread 27-01-2005, 02:22
Zippiot Zippiot is offline
punching bag
no team
 
Join Date: Jan 2005
Location: cali
Posts: 61
Zippiot can only hope to improve
Send a message via AIM to Zippiot
Re: arm design

an interesting thing that i designed and tested was a joystick controlled regulator with psi relief valve. the more forward i moved the joystick the more pressure was allowed in, and if i back out the joystick pressure would be relieved. this made it so that with a load on the piston you can precisely position it where you wish, but it takes some practise.
  #33   Spotlight this post!  
Unread 27-01-2005, 02:56
Sachiel7's Avatar
Sachiel7 Sachiel7 is offline
<Yes I managed to flip it
AKA: Shayne Helms
FRC #1132 (RAPTAR Robotics)
 
Join Date: Sep 2002
Rookie Year: 2002
Location: Richmond, VA
Posts: 541
Sachiel7 is just really niceSachiel7 is just really niceSachiel7 is just really niceSachiel7 is just really niceSachiel7 is just really nice
Send a message via AIM to Sachiel7
Re: arm design

Ok, Here's My $0.02:
Alright, First off, Our Team is Using Pneumatics All the way. ONE Piston for our uber-cool arm.
To give you an idea of the range we can accomplish:
-The Arm Fits within starting size (duh)
-The Arm will utilize Mid-Stroke Positioning (This is "Stopping the piston in between fully out and in") The Mid-Stroke Positioning allows us to stop our arm at any point between retracted and extended. We developed a system in 2003 which also allowed us to do this with our staged forklift, and for those who shun mid-stroke positioning to be "inaccurate", I will try to have some pics or video for you to see how "inaccurate" it is
But anyway, for those interested, the "basic" way to stop the piston mid-way is to block the Exhaust output from the solenoid controlling your piston.
Do a search and you'll quickly find more info on the subject.
Back to our Arm!
-It's capable of "grabbing" a tetra on the ground and capping it onto the center goal, up to 2-3 tetras on Center
-It stacks one at a time (Which I know many of you out there are stacking before hand )
-It can stack 5-6 Tetras on the "Standard" goals
-Our arm will weigh approx. < 20lbs, Including the Four ~4.5 - 5' Counter-Support beams spreading across the chassis.
-The "grabber" section of the arm extends from 8" to 10'4" from ground level.

Now, to be fair, here are a few issues we may see developing with our arm:
-Lack of Air (I'm not too Worried about this one, by the looks of our Pneumatics Board, but always something to look out for! Especially with our Pistons...)
-Tipping (Once again, we've put alot of work into maintaining our CG in our Design, plus its simple and small (surprisingly, yes), so I'm not at worried about this yet either. We also do not extend our arm out very far outside of our robots x,z axis size (38x28)

I hope to have more Info up soon, but for those interested, here's a GIF of a (much) older model of the arm in motion:
http://www.raptar.net/ArmAnim.gif
(This was made a while back, much changes since then )

Hope the info helps!
__________________
-=Sachiel7=-

There's no such thing as being too simple!
Look for Team #1132, RAPTAR Robotics at the VCU Regional this year!
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
Arm Design Input -- Four Bar Linkages Sachiel7 Technical Discussion 4 18-01-2005 01:29
pic: arm design Stephen P Extra Discussion 17 17-01-2005 13:53
Telescopic Arm and grabber design help M. Hicken Technical Discussion 13 17-01-2005 12:56
Arm design - rotation mechanism? n0cturnalxb Technical Discussion 6 16-01-2005 18:28
Reflected Inertia? archiver 2001 9 24-06-2002 03:50


All times are GMT -5. The time now is 07:25.

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