Cable-Driven Redundant Manipulator with Variable Stiffness Mechanisms

With the potential advantages of slender structures and vast degrees of freedom, redundant manipulators have attracted the attention of numerous researchers. However, existing redundant manipulators normally depend their dexterity on a large number of motors. In this paper, the size of the drive system of the redundant manipulator has the potential of miniaturization with the participation of variable stiffness mechanisms and the matched driving strategy. By activating the variable stiffness mechanisms on different elements, any element on the manipulator can be directly controlled with a few motors. The matched driving strategy is described in detail while the kinematic and static analyses of the cable-driven redundant manipulator is carried out. As verification, a prototype of a planar redundant manipulator is constructed, which equips variable stiffness mechanisms utilizing the principle of force amplification near the dead point position of the crank slider mechanism. This work provides a novel potential approach to miniaturize redundant manipulators.