The World's Smallest 20-degree-of-freedom Dexterous Hand, Developed By Chinese Company Encos

The world's smallest 20-degree-of-freedom dexterous hand, developed by Chinese company Encos

A Nanjing-based company has achieved a perfect balance between size and degrees of freedom in its product, breaking through the "impossible triangle" of volume-degrees of freedom-performance. This dexterous hand, named EC-DexHand-5F, not only boasts 20 active degrees of freedom but also stands as the smallest model currently available on the market!

This product made its successful debut at the 2025 Humanoid Robotics and Embodied Intelligence Industry Conference held in Beijing on April 15.

The Smallest 20-Degree-of-Freedom Dexterous Hand:

Dexterous hand technology presents significant challenges, with many industry claims often exaggerated. According to Robot Lecture Hall, numerous manufacturers market their products as "20 degrees of freedom" or "16+ degrees of freedom," yet typically specify "12 active degrees of freedom." Such products generally struggle to gain recognition from overseas enterprises and university laboratories.

The reason lies in mechanical engineering, where degrees of freedom primarily refer to the number of independent motion parameters required for a mechanism to achieve a specific movement. Most so-called 20-DOF dexterous hands on the market fundamentally fail to meet this standard, with their true degrees of freedom limited to the specified active degrees. Consequently, when South Korean robotics company Tesollo launched its five-fingered humanoid gripper Delto Gripper-5 Finger (DG-5F) in February this year, it was touted as the world's smallest product with genuine 20 independent degrees of freedom.

Compared to Tesollo's DG-5F, Inks' newly launched EC-DexHand-5F not only features a smaller size-its volume is identical to that of an adult male hand-but also exhibits a freedom distribution more closely aligned with the human hand. This design facilitates remote operation of the dexterous hand for data collection by leveraging other devices to monitor the state of the human hand.

Technically speaking, robotic dexterous hands are far more complex than other robotic components, and achieving greater degrees of freedom within a smaller footprint is no easy feat. In hardware design, miniaturizing each joint's degrees of freedom requires balancing compactness with structural integrity. For instance, bionic fingers must accommodate drive units, transmission mechanisms, and sensors while maintaining equilibrium between output force and response speed. Material selection for the exterior must also balance lightweight construction with durability, adaptability, and rigidity.

Software algorithms face even greater challenges. Solving real-time equations for high-degree-of-freedom dexterous hands involves highly redundant mathematical optimization problems, necessitating rapid feasible solutions through methods like the pseudoinverse of the Jacobian matrix or neural networks. For instance, during multi-finger coordinated operations, dynamic planning of joint torques is required to avoid self-collision while adapting to varying object shapes and weights-demanding extremely high real-time computational resources. Furthermore, impedance control demands precise modeling of environmental stiffness and damping parameters, while maintaining stability under dynamic disturbances remains a significant challenge.

Inks' approach breaks from conventional structures by implementing an innovative miniaturized joint solution on the EC-DexHand-5F. Each active finger joint is designed as an independent modular unit, integrating a motor, reducer, and driver. This distributed drive-control design enables the dexterous hand to be assembled and disassembled with the flexibility of building blocks. It avoids the complex multi-joint transmission chains found in traditional designs, such as interlocking tendons or linked gears, thereby reducing overall mechanical complexity.

It is foreseeable that the EC-DexHand-5F will deliver superior performance in terms of lifespan and reliability, thanks to its modular joints and redundant cooling design. Inks revealed that the company has planned lifespan stress tests for typical industrial and medical scenarios, with a comprehensive reliability verification report scheduled for release in 2025. This report will provide users across different fields with quantifiable selection criteria. Although final service life data requires validation through real-world operational testing, based on accelerated aging laboratory tests and the historical performance of comparable modules, Inks' product is also expected to deliver impressive durability.