Statics Analysis of Clemen’s Linkage for Robotic Applications

Robotic manipulators can be categorized as either parallel, serial, or in some cases a combination of the two. Among others, a notable drawback of serial manipulators in dynamic applications is the large inertia created by typically heavy electromechanical actuators at the distal end of the manipulator. In addition, compact packaging of multiple actuators in a multi-degree of freedom (DOF) joint, as is often necessary with serial manipulators, can be difficult. These difficulties can be alleviated should a means be found to relocate actuators across one or more degrees of freedom. In this paper, we investigate a constant velocity (CV) linkage, the Clemen’s linkage, that may be used to relocate an actuator across a one DOF revolute joint to an adjacent link while maintaining a serially actuated architecture. This can be very advantageous in some applications such as a humanoid robot ankle. The linkage is analyzed for both its range of motion and torque capacity for such applications given limitations of currently available bearing hardware.