The paper addresses geometric aspects of a spatial three-degree-of-freedom
parallel module, which is the parallel module of a hybrid serial-parallel
5-axis machine tool. This parallel module consists of a moving platform that is
connected to a fixed base by three non-identical legs. Each leg is made up of
one prismatic and two pairs of spherical joint, which are connected in a way
that the combined effects of the three legs lead to an over-constrained
mechanism with complex motion. This motion is defined as a simultaneous
combination of rotation and translation. A method for computing the complete
workspace of the VERNE parallel module for various tool lengths is presented.
An algorithm describing this method is also introduced
