  According to the topological design theory and method of parallel mechanism
(PM) based on position and orientation characteristic (POC) equations, this
paper design a novel 3-translation (3T) PM that has three advantages, i.e., 1)
it consists on three actuated prismatic joints, 2) the PM has analytical direct
position solutions, and 3) the PM is of partial motion decoupling property.
Firstly, the main topological characteristics such as the POC, degree of
freedom and coupling degree are calculated for kinematics modelling. Due to the
special constraint feature of the 3-translation, the analytical direct position
solutions of the PM can be directly obtained without needing to use
one-dimensional search method. Further, the conditions of the singular
configuration of the PM, as well as the singularity location inside the
workspace are analyzed according to the inverse kinematics.
