Abstract: The reachable workspace of 2-DOF 2R serial manipulator is studied and classified. Based on these results, the principle of the theoretical workspace of the spherical 2-DOF 5R manipulator being formed is discussed. According to the conditions of the theoretical workspace existing, design space of this manipulator is established, and all link lengths of the manipulator are contained in the design space. Furthermore, the critical dimensional conditions on which the theoretical work-space will change form one shape to another shape is found out, and design space is divided into several sub-regions by these dimensional conditions. The workspace shapes in different sub-region are different from each other, so all the workspace shapes are classified in design space in detail. The relationship between the link lengths and the workspace area performance index of this manipulator is investigated too, and the area per-formance atlases are plotted in design space. The workspace shape and the value of area are very important for designing the mechanism of manipulator.

Key words: 2-DOF, Design space, Performance atlas, Spherical manipulator, Workspace, Spherical five bar linkage, Metamorphic mechanism, Parallel Mechanism, Reconfigurable mechanism, Screw theory, Type synthesis