FORCE-MOMENT CAPABILITIES OF REVOLUTE-JOINTED PLANAR PARALLEL MANIPULATORS WITH ADDITIONAL ACTUATED BRANCHES

The force-moment capabilities of revolute-jointed planar parallel manipulators (PPMs) are presented. A previously developed analysis that determines explicitly the force-moment capabilities of parallel manipulators is considered and the formulation is improved. This analysis is based upon properly adjusting the actuator outputs to their maximum capabilities. The force-moment capabilities of two actuation layouts are investigated: the non-redundant 3-RRR PPM and the redundantly actuated 4-RRR PPM, where the underline indicates the actuated joint. Four studies of force-moment capabilities are presented: maximum force with a prescribed moment, maximum applicable force, maximum moment with a prescribed force, and maximum applicable moment. These studies are performed for constant payload orientation of the mobile platform throughout the manipulator’s workspace. It is concluded that the manipulator with the additional actuated branch shows an improvement of the force-moment capabilities at the expense of reduc...