Design of spatial adaptive cable-driven parallel robots with an unlimited rotation axis using the cable wrapping phenomenon

Cable-driven parallel robots (CDPRs) are gaining increasing attention due to their low weight, low cost, and power consumption characteristics. However, cable-driven systems have limited rotational capabilities without additional actuator systems. In this paper, we propose a new type of spatial CDPR that provides an unlimited rotation axis without the need for an additional actuator system. This novel capability relies on the cable wrapping over end-effector, which was specifically designed for this purpose. Herein, the principle of the unlimited rotation is demonstrated. Then, the kinematics modelling and the static equilibrium of the spatial CDPRs are established, and the resulting workspace is analysed. The results of the experiment showed that this spatial CDPR exhibits an unlimited rotation axis without additional actuator systems, while the control of the robot remained identical to that of the traditional cable robot.