Published online by Cambridge University Press: 02 April 2013
In this paper, we present the static and dynamic structural characterisation of alow-mobility parallel kinematic manipulator, involving analysis of its stiffness andvibrational dynamic behaviour. The study starts by building numerical models of thebehaviour of the manipulator to be compared to experimental measurements from a prototype.For the case study, we consider a four-degree-of-freedom(x, y, z, θz) manipulatorwith prismatic actuators designed by the COMPMECH research group at the University of theBasque Country. The characterisation allows the behaviour of the static and dynamicstiffness, as well as the natural frequencies of the manipulator, to be mapped in themanipulator workspace. These maps together with kinematic, static and dynamic constraintslead to the definition of operational, static, dynamic and structural workspaces,respectively. Further, we analyse the modes of the manipulator to determine dynamicdisplacements, these being key in the performance in the machining tasks for which therobot was designed.