  The aim of this paper is to give a detailed examination of the input and
output singularities of a 3-RUU parallel manipulator in the translational
operation mode. This task is achieved by using algebraic constraint equations.
For this type of manipulator a complete workspace representation in Study
coordinates is presented after elimination of the input parameters. Both, input
and output singularities are mapped into a Study subspace as well as into the
joint space. Therewith a detailed singularity investigation of the
translational operation mode of a 3-RUU parallel manipulator is provided. This
paper is an extended version of a previous publication. The addendum comprises
the discovery of a possible transition between two operation modes as well as a
self motion and an examination of another component of the output singularity
surface, most of them for arbitrary design parameters.
