Design and Optimal Control of an Underactuated Cable-Driven Micro-Macro Robot

In this paper, a planar underactuated cable-driven micro-macro robot is presented. The system consists of two-link passive serial manipulator attached to a cable-suspended parallel robot. The system is conceived for applications requiring point-to-point motions inside large workspaces in the presence of obstacles: The serial arm allows us to reach points close to the obstacles that would not be reachable by the cable robot alone due to cable-obstacle interference. The kinematic and dynamic models are presented and the differential flatness framework is applied to make the system controllable for point-to-point movements. In addition, a multiobjective optimization framework is presented, which allows us to choose the design parameters that minimize two conflicting objective functions (movement time and control effort) for a given movement task. This novel approach allows designers to infer useful information about the influence of the design parameters on the dynamic performance of the system.