Optimal design of a two degree of freedom manipulandum for human motor control studies

Perhaps the most common configuration for planar manipulandums used in motor control studies is the serial five-bar linkage, but this design suffers from strongly directional inertia and force production characteristics. An alternative parallel-link design whose properties are less direction-sensitive across the workspace has been used in wrist-motion studies, but has never been sealed up for full arm experiments. This paper describes how this design can be optimized for human arm movement studies based on three criteria: workspace size, workspace shape, and minimum force-to-torque ratio.