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In lugnet.technic, Chris Shepherd wrote:
> I have built a realistic grasping end effecter that can feel
> when something in is its grasp (without touch sensors).
Nice. And I agree, nice-looking. I once Bricklinked some of those same "rubber
skirt" pieces for this, but never did get them in an effecter that I liked (I
was trying smaller at the time). Now I use the flexible 1x2 studless beams that
first showed up in some of the old hockey sets:
http://www.peeron.com/inv/parts/45590
These seem to make ideal, compliant "fingers" to pick things up.
> there are two rotation sensors, one with a
> rigid spur gear and one with a slip clutch
> gear.
I must be missing something - why use two rotation sensors? Just monitor the one
on the clutch gear - if it stops advancing and the program is still commanding
the motor to turn, you know that the jaws have stalled and the fingers are on
something. If you're careful about how you use the rotation readings, you can
even tell the rough size of whatever the gripper is holding. I've used this on
the NXT on several occasions (although not for a gripper), with the nice feature
that there it requires *no* sensor ports (the rotation sensor is built into the
motor).
Here's an example of a way to "DetectStall" on the NXT:
http://www.brickshelf.com/cgi-bin/gallery.cgi?i=2036021
--
Brian Davis
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Message has 1 Reply:
 | | Re: End effector that can "feel"
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| (...) I was comparing sensor reading to sensor reading and your point compares sensor reading to motor on/off condition, which is even better. I have never considered your idea of motor stall. That is probably because I am notorious for high gear (...) (16 years ago, 19-Jan-08, to lugnet.technic, lugnet.robotics)
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Message is in Reply To:
| | End effector that can "feel"
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| Hey everyone. I have built a realistic grasping end effecter that can feel when something in is its grasp (without touch sensors). I have attached a deconstructed version that I use. (URL) principle is pretty simple. As the end effecter closes and (...) (16 years ago, 18-Jan-08, to lugnet.technic, lugnet.robotics)
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