Self-reconfigurable planar parallel robot in the horizontal plane

Abstract

This paper proposes a self-reconfigurable planar parallel robot which is capable of reconfiguring itself to various types of planar parallel robots in the horizontal plane. The robot can change its workspaces by coupling and decoupling of a platform and two or more 2R open kinematic chains with second joints unactuated (limb). The platform should be light and therefore no additional actuators are used for reconfigurations. We have already shown that uncertainty singular configurations are appropriate for coupling of two limbs. This paper describes positive and negative aspects of the uncertainty singularity for coupling and decoupling. In addtion, decoupling needs to be carried out with more care than coupling. It must be considered to assure the safety of a decoupled limb and to prevent unexpected decoupling of other limbs. We propose feasible coupling and decoupling configurations for the proposed self-reconfigurable planar parallel robot. We also introduce our real robot and show its coupling mechanism, which is designed to be easy to couple and hard to decouple. Experiments are carried out to verify reconfigurations to change workspaces.