# Design, Modeling, and Experimental Verification of a Fully Decoupled Tendon-Driven Humanoid Arm

## TL;DR

A new tendon-driven humanoid arm is designed and tested, mimicking human movement with mechanical decoupling and high precision.

## Contribution

The paper introduces a fully decoupled tendon-driven humanoid arm with mechanical-level joint space decoupling and biomimetic passive stiffness.

## Key findings

- The prototype achieved a mean positioning error of 0.40 mm and a maximum end effector velocity of 3.62 m/s.
- Passive joint stiffness matched the order of magnitude of human upper limbs.
- The design enables rapid whole-arm motion and mechanical joint space decoupling without complex compensation.

## Abstract

Human upper-limb movement is produced through the antagonistic action of tendons and is controlled in a joint space-oriented manner. Inspired by this functionality, a fully decoupled tendon-driven humanoid arm (FDTDH-Arm) is proposed, in which joint space decoupling is achieved at the mechanical level via humanoid antagonistic actuation and joint regulation rather than complex modeling-based compensation. To characterize the motion behavior introduced by rolling constraints, joint-level and whole-arm kinematic models are established. A prototype of the proposed arm is developed and experimentally validated. The results demonstrate effective mechanical joint space decoupling, passive joint stiffness of the same order of magnitude as that reported for the human upper limb, a mean positioning error of 0.40 mm, and rapid whole-arm motion with a maximum end effector velocity of 3.62 m/s. The proposed design provides a mechanical implementation and biomimetic solution for humanoid manipulation in human-interactive environments.