An optimization procedure regarding shape of usable workspace and antagonistic stiffness is developed for a redundantly actuated parallel manipulator. The kinematic parameters such as configuration of the mechanism and length of linkages are optimized to maximize and equal out antagonistic stiffness of the redundantly actuated manipulator when the shape of usable workspace is given as a rectangle. The proposed procedure is verified by simulation and experiment with a 2-DOF planar manipulator. In the experiment, the principal axes of displacements of ellipses are measured when the corresponding external forces are imposed on the end-effector. The simulation and experimental results show that the proposed procedure is valid for designing the redundantly actuated parallel manipulator with maximum antagonistic stiffness.Index Terms-Antagonistic stiffness, mechanism design of manipulators, parallel robots, redundant robots.
In this paper, an experimental verification of antagonistic stiffness planning is presented for a 2-DOF parallel mechanism with four actuators. With 2-DOF force redundancy, the magnitude and direction of the stiffness enhancement can be controlled by the additional actuators, where the internal torques of the mechanism exist on the two-dimensional null space. In the experiments, the passive and active stiffness are measured, respectively, during endowing the external force at the end-effector. Two stiffness assignment methods for a given pathway are suggested and are verified by the experiments.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.