Stiffness Modulation of a Cable-Driven Serial-Chain Manipulator Via Cable Routing Alteration

Cable-driven serial-chain manipulators, CDSMs, are widely used from industries to human-robot interaction applications demanding diverse performance requirements. The CDSMs inherent characteristic of flexibility in altering system parameters facilitates the possibility of varying its performance as per the desired application and thus has been explored in the literature. Among the various performance measures, stiffness plays a vital role in manipulators interaction with unknown environments. Works in the literature reported varying CDSMs system parameters to tune the stiffness characteristics and highlighted the tensionable workspace's sensitivity to the changes in the system parameters. The current work demonstrates the potential of co-shared cable routing in CDSMs along with a set of design conditions to provide a broader range of stiffness characteristics for a constant tensionable workspace. The results are presented using a planar two degrees-of-freedom (DOFs) CDSM, and the stiffness changes are validated experimentally. This outcome shows that CDSM with co-shared cable routing can render a wide range of stiffness behavior.