[comp.robotics] Unimation joint angle alter mode

dms@ai.mit.edu (David M. Siegel) (08/23/90)

Does anyone know if there is a version of VAL for Unimation controllers
that supports alter mode in joint angles, rather than in world coordinates.

Thanks,

-Dave

loucks@intvax.UUCP (Cliff Loucks) (08/25/90)

From article <10286@life.ai.mit.edu>, by dms@ai.mit.edu (David M. Siegel):
> Does anyone know if there is a version of VAL for Unimation controllers
> that supports alter mode in joint angles, rather than in world coordinates.

Isn't that what they call their "Slave" package?  I'll check with a
person here who is working in telerobotics.  He has a PUMA 560 that
he has used to implement a system which prevents the operator from
manually driving the robot into known objects in it's workspace.
He's disconnected the teach pendant from the Unimation controller
and put his "KRITIC" controller between the pendant and VAL.  As the
operator manually guides the robot with the pendant, the command
signals are intercepted and checked to see if the robot would either
collide with anything or if a joint limit is approaching.  He uses
a repulsive field algorithm to guide the tool around objects or to
ramp the speed down when approaching a boundary like a table top.
As I recall, his hook to the Unimation controller is through
their slave interface.  

Cliff
-- 
A society is not civilized until it domesticates the icecube.

Cliff Loucks  <=>  loucks@intvax.UUCP
Sandia National Labs, Albuquerque, New Mexico