RAPID Hand Prototype: Design of an Affordable, Fully-Actuated Biomimetic Hand for Dexterous Teleoperation

TL;DR

The paper tackles the limited accessibility of dexterous robotic hands by introducing RAPID Hand, a low-cost, fully actuated $20$-DoF five-finger hand with palm-mounted motors and four-phalanx fingers. It couples a novel universal phalangeal transmission for non-thumb fingers with an omnidirectional thumb actuation mechanism to mimic human hand dexterity, and pairs this hardware with a high-DoA teleoperation interface and a one-shot retargeting method based on SLSQP optimization. Quantitative metrics (thumb opposability and manipulability) and qualitative retargeting assessments demonstrate improved dexterity over comparable low-cost hands, while real-world tests in retrieval, ladle use, and piano-like playing illustrate practical viability. The work emphasizes affordability, maintainability, and extensibility, including open-source release to accelerate research in dexterous teleoperation and data collection for embodied AI. Overall, RAPID Hand presents a compelling, scalable path toward high-DoA dexterous teleoperation suited for Learning from Demonstrations and real-robot data collection.

Abstract

This paper addresses the scarcity of affordable, fully-actuated five-fingered hands for dexterous teleoperation, which is crucial for collecting large-scale real-robot data within the "Learning from Demonstrations" paradigm. We introduce the prototype version of the RAPID Hand, the first low-cost, 20-degree-of-actuation (DoA) dexterous hand that integrates a novel anthropomorphic actuation and transmission scheme with an optimized motor layout and structural design to enhance dexterity. Specifically, the RAPID Hand features a universal phalangeal transmission scheme for the non-thumb fingers and an omnidirectional thumb actuation mechanism. Prioritizing affordability, the hand employs 3D-printed parts combined with custom gears for easier replacement and repair. We assess the RAPID Hand's performance through quantitative metrics and qualitative testing in a dexterous teleoperation system, which is evaluated on three challenging tasks: multi-finger retrieval, ladle handling, and human-like piano playing. The results indicate that the RAPID Hand's fully actuated 20-DoF design holds significant promise for dexterous teleoperation.

Figures (10)

• Figure 1: (a) RAPID Hand Prototype: a low-cost, fully-actuated, five-fingered hand, each with four phalanges. (b) Dexterous teleoperation using an intuitive teleoperation interface to perform three challenging tasks: multi-finger retrieval, ladle use, and human-like piano playing.
• Figure 2: (a) Multi-view of the index finger with universal phalangeal transmission scheme. Red indicates MCP-1 transmission, purple for MCP-2, blue for PIP, and green for DIP. (b) Effect of Joint Motion on Gear Transmission. As the PIP motor rotates the PIP by $\theta$ and DIP motor remains stationary, gear G1 stays fixed, while G2 rotates, causing the DIP joint to rotate by $\theta'$ relative to the IP.
• Figure 3: Simplified human hand kinematics.cerulo2017teleoperation
• Figure 4: Mechanical design of the thumb finger. The red and orange sections represent the TM joint transmission gear set, the blue section represents the MCP transmission gear set, and the green section represents the IP transmission gear set.
• Figure 5: Thumb TM joint actuation. When SBM1 and SBM2 rotate at equal speeds in the same direction, the TM joint rotates around the TM-1 axis. When SBM1 and SBM2 rotate at equal speeds in opposite directions, the TM joint rotates around the TM-2 axis.