Comparative analysis of a new 3×PPRS parallel kinematic mechanism

• A new six degree-of-freedom (dof) Parallel Kinematic Mechanism (PKM) architecture based on a 3×PPRS topology is presented and analyzed.
• The stiffness (static stiffness using matrix structural analysis and dynamic stiffness using FEA) of the proposed PKM is compared with similar three known 6-dof architectures.
• It is shown that the proposed PKM can achieve high (platform) tilt angles and that it exhibits higher stiffness relative to the three similar known PKMs.
• A prototype Reconfigurable meso-Milling Machine Tool (RmMT), which is based on the proposed PKM that was designed and built, is presented.

Parallel Kinematic Mechanisms (PKMs) are well suited for high-accuracy applications. However, constraints such as end-effector rotation (i.e., platform tilt angle) and configuration-dependent stiffness often limit their usage. A new six degree-of-freedom (dof) PKM architecture based on a 3×PPRS topology that addresses these concerns is presented in this paper – specifically, the proposed PKM can achieve high (end-effector) tilt angles with enhanced stiffness. The mechanism is also compared with similar three known 6-dof architectures, through which it is shown that the proposed PKM indeed exhibits higher stiffness relative to these three reference PKMs. The static stiffness is derived using matrix structural analysis, and the dynamic stiffness is obtained via finite-element analysis. A prototype of the proposed PKM that was designed and built is presented.