MM-Hand: A 21-DOF Multi-modal Modular Dexterous Robotic Hand with Remote Actuation

2026-04-19

AI Summary

This work addresses the limitations of high-degree-of-freedom dexterous hands—namely, bulky actuators, excessive distal mass, and severe heat generation—which hinder sensing capabilities and maintainability. The authors propose a remote tendon-driven design that relocates motors away from the hand, integrating modular 3D-printed structures with a multimodal sensing system encompassing joint angles, tactile feedback, motor current, and intra-palm stereo vision. This approach yields a lightweight, highly maintainable 21-degree-of-freedom hand with rich perceptual capabilities. Key innovations include spring-return tendon-driven fingers, rapid tendon connectors, and a systematic analysis of sheath length and friction losses to optimize transmission efficiency and control performance. The system achieves 25 N fingertip force under 1-meter remote actuation, demonstrating robust load capacity, sensing accuracy, and closed-loop control efficacy. All hardware and software are openly released.

Technology Category

• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Computer Vision: Multi-modal Vision
• Humans and AI: Brain-Sensing and Analysis

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems

Abstract

High-DOF dexterous hands require compact actuation, rich sensing, and reliable thermal behavior, but conventional designs often occupy valuable in-hand space, increase end-effector mass, and suffer from heat accumulation near the hand. Remote tendon-driven actuation offers an alternative by relocating motors to the robot base or an external motor hub, thereby freeing the fingers and palm for additional degrees of freedom, sensing modules, and maintainable mechanical structures. This paper presents MM-Hand, a 21-DOF Multimodal Modular dexterous hand based on remote tendon-driven actuation. The hand integrates spring-return tendon-driven fingers, modular 3D-printed finger and palm structures, quick tendon connectors for maintenance, and a multimodal sensing system including joint angle sensors, tactile sensors, motor-side feedback, and in-palm stereo vision. We further analyze tendon-sheath length variation and friction loss to guide the design of the routing, motor hub, and closed-loop joint control. Experiments validate the transmission, output force, sensing, and control capability of the system. The fingertip force reaches 25N under a 1m remote sheath transmission, demonstrating practical load capacity despite long-distance tendon routing. Closed-loop joint-level experiments further evaluate command tracking with a static arm and during arm motion. These results show that MM-Hand provides a lightweight, sensor-rich, and maintainable hardware platform for dexterous manipulation research. To support the community, all hardware designs and software frameworks are made fully open-source at https://mmlab.hk/research/MM-Hand.

Problem

• dexterous robotic hand
• remote actuation
• tendon-driven
• thermal management
• compact design

Innovation

• remote tendon-driven actuation
• multimodal sensing
• modular dexterous hand
• 21-DOF
• open-source robotic hand