Workspace enlargement for parallel kinematic machines

This paper presents an approach that allows parallel kinematic machines to move through singular poses typically connected with them. Using this the usable workspace of parallel kinematic machines can be significantly increased. This compensates the main disadvantage of parallel kinematic machines, i.e. the sometimes poor ratio of workspace to machine size. Their main advantage, the higher structural stiffness, is maintained. To efficiently apply this to the kinematic design of production machines, different types of workspaces are defined. Finally a robot is presented that passes through singular poses and shows the possibilities in increasing machine performance by applying the presented method.