A method and apparatus are provided for estimating and/or precluding
stick-slip, or other oscillatory or resonant behavior, through use of a
virtual transducer, which precludes the need for having sensors located
adjacent to a driven element of the system, or adjacent contact surfaces
at which the stick-slip relative motion may occur. Parameters measurable
at a drive mechanism are utilized for controlling a system in a manner
which precludes stick-slip, or other oscillatory or resonant behavior, of
the driven element. Relative motion between contacting surfaces in the
driven element, prone to stick-slip behavior, is controlled such that,
after sufficient force is applied by the drive element to overcome static
friction forces between the contacting surfaces and break them free from
one another, relative motion between the surfaces is maintained at a high
enough relative speed that the surfaces are precluded from statically
contacting one another, so that stick-slip behavior is precluded.