This paper
presents a kinematic analysis and design characteristics of an in-parallel
manipulator developed for the probing task application that requires high
precision, active compliance, and high control bandwidth. The developed manipulator
is a class of six-degree-of-freedom in-parallel platforms with 3 PRPS
(prismatic-revolute-prismatic-spherical joints) chain geometry. The main advantages of this manipulator,
compared with the typical Stewart platform type, are the capability
of pure rotation generation and the easy prediction of the
moving platform motion. The purpose of this paper is to
develop an efficient kinematic model which can be used for
real-time control and to propose systematic methods to design the
manipulator considering workspace, manipulability, resistivity, singularity, and the existence conditions
of the forward kinematic solution. Particularly, we propose a new
method for checking the singularity of the parallel manipulator using
the translational and rotational resistivity measures. A series of simulation
are carried out to show kinematic characteristics and performance of
the manipulator mechanism. A prototype manipulator was built based on
the kinematic analysis results.