| Popis: |
In flexible manufacturing systems, straight line motions are often required in part handling, assembly, cutting, sealing, or welding operations. Rather than using a high performance industrial robot to execute the path directly, employment of a less precise robot outfitted with an end-of-arm tool comprising an exact straight line mechanism could be more effective in both performance and in cost. Exact straight line mechanisms with pin connections are easy to manufacture and assemble, in comparison to those realized by translational joints where alignment of linear axes or surface could be problematic. Such an issue becomes even more difficult when relatively large stroke and/or high precision of straight line motion is required. In this paper, a study of the kinematic characteristics of a special class of exact straight line mechanisms, Hart’s Inversor Type III, with emphasis toward dimension synthesis, is presented. An analytical approach for sizing the link lengths with respect to a desirable straight line stroke constraint is developed and illustrated with examples. Also presented are stiffness and mechanical advantage characteristics for additional design considerations. |
