Dear Subscribers,

Thank you for your numerous comments regarding our last technical report about
the 3-DOF 3-UPU translational parallel mechanism. We are glad to announce that
Prof. Manfred Husty has confirmed our beliefs that the SNU parallel mechanism
does not have an architecture singularity in the studied configurations (when
all legs are of equal length).

While we were working on the report on the singularity of the SNU robot we felt
the concept of constraint singularity must apply to other mechanisms with fewer
degrees of freedom than the maximum possible. This turned out to be correct,
and so, we bring you this new technical report on constraint singularities
( Our goal was to reveal the
general nature and the kinematic implications of this particular mobility

We also release the promised review on haptic devices based on parallel
mechanisms ( The review,
written by Lionel Birglen, illustrates the state of the art of this interesting
application of parallel mechanisms.

We hope you will enjoy both the report and the review and we would like to ask
you to address your correspondence regarding the report to all authors.

Yours sincerely,

Ilian Bonev

July 5, 2001

* Servotest, producer of servo-hydraulic test systems