The relationships between the shapes of the workspaces and the link lengths of 3-DOF symmetrical planar parallel manipulators

The workspace for robotic manipulators is a very important issue for optimum design of robots, especially for parallel manipulators. The relationship between the shapes of workspaces and the link lengths of manipulators is very close. In this paper, 3-DOF planar parallel manipulators (3-DOF PPMs) are classified; various of shapes of the workspaces are presented; the relationships between the shapes of the workspaces and the link lengths of each of the classifications are presented. The results of this paper are useful for the designers not only to understand the distribution of characteristics of the workspaces for various link lengths of 3-DOF PPMs, but also to optimize the manipulators.