| Parallel manipulators are increasingly being used nowadays due to the advantages over their serial counterparts such as higher load carrying capacity. From a design perspective, it is important to find the maximum load which can be applied or sustained by a particular parallel manipulator. Force-moment capability analysis is used for this purpose. Actuation redundancy, which translates into more actuation options than required to perform a particular task, allows the force-moment capabilities of a manipulator to he optimized. Two methods, namely a scaling factor method and an explicit analytical method, have been proposed for determining the force moment capabilities of redundant planar parallel manipulators. In this research, both met hods are extended to spatial parallel manipulators using the 6-DOF (degrees-of-freedom) 3-RRRS manipulator as an example. Both methods are then compared. The explicit analytical method is further used for finding the force-moment workspaces, which are representations of the workspace regions where the manipulator can at least apply/sustain a particular desired value of force or moment in any direction. This method can be used in the design phase for the analysis of force-moment capabilities of parallel manipulators before using them in industrial or space applications. |
