Comparative Analysis of a Redundant Pentapod Parallel Kinematic Machine

Parallel kinematic mechanisms (PKMs) provide high stiffness and compact structures that are suitable for a large number of applications, including 5-axis milling. This paper presents a new pentapod-based PKM with an additional redundant degree-of-freedom (DOF) capable of reaching platform tilt angles of at least 90 deg over a large workspace. The proposed new PKM has a 6DOF 4 × SPRR + 1 × PSPR architecture. It is compared herein to Metrom® Pentapod as well as to several other pertinent PKMs in terms of workspace and dynamic stiffness. It is shown that the proposed mechanism can yield a tangibly larger workspace volume, when compared to those PKMs, while maintaining its high stiffness characteristics.