Optimization and implementation of a high-speed 3-DOFs translational cable-driven parallel robot

Abstract

Cable-driven parallel robots (CDPRs) inherit the high load capacity and outstanding dynamics of the parallel mechanism, as well as the low inertia and large workspace of the cable mechanism. Accordingly, CDPRs present excellent application prospects as high-speed pick-and-place robots. In this study, a non-redundant CDPR, named T-Bot, is designed and tested. The T-Bot is actuated by three pairs of parallel cables and tensioned by a passive spring. First, the configuration is illustrated. The kinematics are established, and the workspace is determined. Then, the performance evaluation and optimization design methods of CDPRs are proposed based on force transmission. The force transmission performance of CDPRs is defined as the force synthesis capability at the end effector, and divided into the actuation performance and the constraint performance. Two indices are further defined accordingly, and the kinematic optimization of the T-Bot is accomplished. The spring parameters are determined considering both the acceleration and cable force. Analysis results reveal that the proposed T-Bot has a large workspace with high acceleration capability. A prototype is fabricated, and the typical pick-and-place motion is realized after experimental verification of the large workspace and acceptable dynamic performance.