Kinematic Performance Criteria

Abstract

This chapter presents the criteria of performance evaluation for parallel mechanisms with the focus of the kinematic aspects, i.e., workspace, dexterity, motion/force transmission and singularity. Workspace is one of the most important criteria in the design of parallel mechanism, wherein its quality that reflects the shape, size and presence of singularities is of primary importance. The Jacobian matrix based condition index is commonly used to measure the kinematic dexterity of a robotic manipulator. The motion/force transmission index is defined by the virtual power coefficient from the screw theory, which is related to the transmission/pressure angle. Singularity of the parallel mechanisms can be identified from either Jacobian matrix or motion/force transmissibility both graphically and numerically.