Cable configuration analysis to increase the rotational range of suspended 6-DOF cable driven parallel robots

A cable-driven parallel robot (CDPR) is a special type of parallel robot. In the past two decades, CDPRs have been attracted a lot of attention since they have various advantages such as large workspace, low energy consumption, heavy payload capability and easy re-configurability. Especially, the greatest strength is that workspace can be expandable easily. CDPRs have enough large workspace inside an installed frame when the end-effector (EE) moves only translationally. However when the rotational motion of end-effector is used, the workspace is reduced substantially. To increase the workspace in the case that EE needs to rotate, there are two methods. One is to introduce a new mechanism of EE to change configuration parameters. Another is to change the cable configuration. In this paper, a cable configuration to increase the rotational workspace is proposed and analyzed. Using Wire Center software, workspaces were analyzed according to methods of cable connection. It is shown that the rotational workspace of the suspended 6-DOF CDPR is improved. This result is expected to influence the application expansion of CDPRs.