Stiffness estimation of a tripod-based parallel kinematic machine

This paper presents a simple yet comprehensive approach that enables the stiffness of a tripod-based parallel kinematic machine to be quickly estimated. The approach can be implemented by two steps. In the first step, the machine structure is decomposed into two substructures associated with the machine frame and the parallel mechanism. The stiffness model of each substructure is formulated by assuming that the components in the other substructure are rigid. This is followed by the second step that enables the stiffness model of the machine structure to be achieved by linear superposition. A 3D representation of the stiffness distributions within the usable workspace are depicted with comparison to those obtained through the finite element analysis.