In context
In early 2024, soft robotics was gaining traction in industrial and assistive applications, yet supernumerary robotic limbs (SRLs) remained largely rigid, limiting their safety and dexterity. This work from Nanjing University of Aeronautics and Astronautics and Hohai University addressed the need for flexible, controllable SRLs capable of complex 3D tasks.
What was reported
The team designed a soft SRL using fiber-reinforced actuators (FRAs) inspired by octopus tentacle muscle fibers. FRAs, made of silicone with embedded Kevlar fibers, can extend, expand, bend, and twist by varying fiber angles and applying air pressure. The SRL comprises parallel FRA modules connected in series, with optional end effectors like suction cups or grippers.
Analytical models were developed to predict deformation based on configuration parameters and input pressure, validated by finite element simulation. A trajectory optimization algorithm using a multi-objective function and trust region method was proposed to tune FRA parameters for task assistance.
Prototype tests showed improved wearing comfort and flexible 3D motion. The authors report that the FRA-driven SRL outperforms existing soft SRLs in comfort, motion variety, and control precision.
Why it mattered
This research advanced soft SRLs toward practical use in manufacturing and daily tasks, offering a safer, more adaptable alternative to rigid exoskeletons. The modeling and optimization approach could enable precise control of soft actuators, supporting broader adoption in human-robot collaboration.
"The research results demonstrate that the SRL driven by FRAs is superior to the state-of-the-art soft SRLs in terms of providing a comfortable wearing experience, enabling various motions, and ensuring precise control."
Source: 《机器人》期刊 (robot.sia.cn) · Published 2024-03-27 · “仿生柔性外肢体机器人的优化设计与实现”