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Subject: 
Re: an idea, can someone tell me if this is possible/been donebefore/etc?
Newsgroups: 
lugnet.robotics
Date: 
Tue, 2 Dec 2003 21:49:09 GMT
Viewed: 
1072 times
  
In lugnet.robotics, "Rob Limbaugh" <RLimbaugh@greenfieldgroup.com> wrote:



<SNIP>

With regard to obstacle detection for legs, I was playing
around with various ways of measuring the increased torque a
motor puts out in a stalled condition. I was thinking of a
spring (ie rubber band) loaded co-axial ratchet/cam that
would hit a switch to tell the robot the leg was blocked and
it needed to be put down now. That way it would work
irrespective of the direction of translation (things can
block the leg both ways).

Look up Tri-Star Wheel.  Instead of driving wheels, drive gears that
move legs (or pneumatic pumps).

Doug Carlson has working examples:

http://www.visi.com/~dc/


Remember that a Tri-Star Wheel uses a differential.  When the input
shaft is turned, it spins the body of the differential which turns the
individual wheels in the Tri-Star configuration.  When a wheel hits an
obstacle, it stops the differential body from rotating so the output
shaft begins to rotate which spins the entire Tri-Star wheel.

If the differential body was connected to the drive train that swings
the leg forward/backward and the output shaft was connected to the
lift/lower drive train, then when the leg stalls (forward/backward) the
system would engage the lift/lower drive train.

Hopefully that made sense...

I understand it.


- Rob

Kevin



Message is in Reply To:
  RE: an idea, can someone tell me if this is possible/been donebefore/etc?
 
<SNIP> (...) Look up Tri-Star Wheel. Instead of driving wheels, drive gears that move legs (or pneumatic pumps). Remember that a Tri-Star Wheel uses a differential. When the input shaft is turned, it spins the body of the differential which turns (...) (21 years ago, 2-Dec-03, to lugnet.robotics)

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