Design Optimization of Three-Dimensional Wire Arrangement Considering Wire Crossings for Tendon-driven Robots
This addresses the challenge of empirical and oversimplified wire arrangement design for tendon-driven robots, which are used in applications like robot hands and wrists, though it appears incremental by extending prior work to 3D with crossings.
The study tackled the problem of designing wire arrangements for tendon-driven robots by proposing a three-dimensional optimization method that accounts for wire crossings, demonstrating its effectiveness on a 3D link structure with sufficient joint torque along a target trajectory.
Tendon-driven mechanisms are useful from the perspectives of variable stiffness, redundant actuation, and lightweight design, and they are widely used, particularly in hands, wrists, and waists of robots. The design of these wire arrangements has traditionally been done empirically, but it becomes extremely challenging when dealing with complex structures. Various studies have attempted to optimize wire arrangement, but many of them have oversimplified the problem by imposing conditions such as restricting movements to a 2D plane, keeping the moment arm constant, or neglecting wire crossings. Therefore, this study proposes a three-dimensional wire arrangement optimization that takes wire crossings into account. We explore wire arrangements through a multi-objective black-box optimization method that ensures wires do not cross while providing sufficient joint torque along a defined target trajectory. For a 3D link structure, we optimize the wire arrangement under various conditions, demonstrate its effectiveness, and discuss the obtained design solutions.