Towards development of a 2-DOF planar oparallel robot with optimal workspace use

Abstract

One of the main drawbacks of parallel robots is their relatively small workspace. Furthermore, this workspace is often segmented by singularities. The most direct approach to making better use of the robot's workspace is to devise control methods for crossing Type 2 singularities. However, near these singularities, the robot precision is very poor and thus the usable workspace remains segmented. In general, parallel robots with multiple working modes (inverse kinematic solutions) have different Type 2 singularity loci for each working mode. Thus, by crossing Type 1 singularities only, these robots can make optimal use of their workspace with simple control strategies. While this idea is not entirely new, this paper is the first to apply it to a 2-DOF planar parallel robot with revolute joints only, in the context of practical implementation.