View Full Version : hand / finger joint torques and more

Jessica Banks
05-19-2003, 01:37 AM
I am working on my Ph.D.. at the Artificial Intelligence Lab and MIT.
My research involves building the hardware and software for a robotic
hand with general grasping dexterity (that is, I want the hand to be
able to pick up a very wide variety of things e.g., pencils, a can, a
sheet of paper, an egg, oddly shaped objects, a handful of rice, etc.).
This will all be done, initially without vision.

The first task of the robot will be to turn a door knob (the crank type,
not the round type). This will mostly be done by the wrist actuators
(the arm is being done by another colleague), but the fingers of the
robot hand must be able to secure a tight hold on the handle. I have
looked all over for references about the finger joint torques required
to this, but seem to be coming up short. (The handle turning torque is
about 13in-lb (5lb at 2.6in) but again that is mostly from the wrist).
I was wondering if any of you know good references for human grip
strengths. Such info will help me choose my actuators for the hand. I
realize this depends on coefficients of friction, finger configuration,
etc. but I am trying to get a rough estimate based on anthropometric data.
For instance, does anyone know the minimum grip strength required for a
secure prismatic grasp? Maybe data from studies of impaired hand
strength patients?

On another note, (and maybe more appropriate for this list) the software
I am working on involves computational/computer models of muscle
function (synergistic, antagonistic, mutlijoint), so I would also
welcome any references to such things. I have some, but would like to
cover all the possibilities very thoroughly.
I look forward to hearing any suggestions and references that you might

Thanks in advance,

jessica banks
massachusetts institute of technology
artificial intelligence laboratory
200 technology square, room 937 cambridge, MA 02139
o: 617.253.7471 f: 617.253.0039

To unsubscribe send SIGNOFF BIOMCH-L to LISTSERV@nic.surfnet.nl
For information and archives: http://isb.ri.ccf.org/biomch-l