Development of 2DOF Manipulator using Geared Five-bar Modules with Multiple Operation Modes

A 2DOF (degrees of freedom) manipulator driven by two 1DOF geared five-bar modules is proposed. The geared five-bar module is realized by interlocking two joints of a five-bar linkage by means of gears, and can easily switch its motion trajectory by reconfiguring the gears. Consequently, the manipulator is expected to have multiple operation modes with different kinematic properties. The objective of this research is to develop working model of such a manipulator that can switch kinematic properties depending on the tasks. In this paper, the above functions are verified through kinematic analyses and basic motion experiments using prototype working models of the geared five-bar module and the 2DOF manipulator. The kinematic analyses include the solutions to the direct kinematics and the inverse kinematics problems, the movable range analysis, and the manipulability analysis based on the Jacobian matrix (The shapes of the manipulability polytopes change depending on the operation modes).