Cobots: Robots for Collaboration with Human Operators
3
J. Edward Colgate
Witaya Wannasuphoprasit
Michael A. Peshkin
Proceedings of the International Mechanical Engineering Congress and Exhibition, Atlanta, GA, DSC-Vol. 58, pp. 433-39
1996 ASME
http://haptic.mech.northwestern.edu/library/colgateje/imece96/imece96.ps
A "cobot" is a robotic device which manipulates objects in
collaboration with a human operator.  A cobot provides assistance to
the human operator by setting up virtual surfaces which can be used to
constrain and guide motion.  While conventional servo-actuated haptic
displays may be used in this way also, an important distinction is
that, while haptic displays are active devices which can supply energy
to the human operator, cobots are intrinsically passive.  This is
because cobots do not use servos to implement constraint, but instead
employ "steerable" nonholonomic joints.  As a consequence of their
passivity, cobots are potentially well-suited to safety-critical tasks
(e.g. surgery) or those which involve large interaction forces
(e.g. automobile assembly).  This paper focuses on the simplest
possible cobot, which has only a single joint (a steerable wheel).
Two control modes of this "unicycle cobot", termed "virtual caster"
and "virtual wall" control, are developed in detail.  Experimental
results are also presented.