Development of a 15-Degree-of-Freedom Bionic Hand with Cable-Driven Transmission and Distributed Actuation

TL;DR

The paper tackles the challenge of achieving human-like dexterity with a compact actuator count by introducing a 15-DoF bionic hand with a distributed drive architecture: five forearm motors for grasping and ten palm motors for manipulation, connected via a novel 3-DoF parallel tendon transmission. It details the mechanical layout, the corresponding electronics and control framework, and derives a forward kinematic model with torque mappings to motor actuators. Experimental validation demonstrates a fingertip force of 11 N, a per-finger workspace around 99 cm³, and 33 grasp types per the Grasp Taxonomy, indicating strong dexterity and manipulation capabilities in a lightweight device (~1.4 kg). The results suggest that distributed drive designs can achieve high power density and versatile manipulation while maintaining human-scale dimensions, with future work targeting tactile sensing and wrist enhancements to further expand functionality.

Abstract

In robotic hand research, minimizing the number of actuators while maintaining human-hand-consistent dimensions and degrees of freedom constitutes a fundamental challenge. Drawing bio-inspiration from human hand kinematic configurations and muscle distribution strategies, this work proposes a novel 15-DoF dexterous robotic hand, with detailed analysis of its mechanical architecture, electrical system, and control system. The bionic hand employs a new tendon-driven mechanism, significantly reducing the number of motors required by traditional tendon-driven systems while enhancing motion performance and simplifying the mechanical structure. This design integrates five motors in the forearm to provide strong gripping force, while ten small motors are installed in the palm to support fine manipulation tasks. Additionally, a corresponding joint sensing and motor driving electrical system was developed to ensure efficient control and feedback. The entire system weighs only 1.4kg, combining lightweight and high-performance features. Through experiments, the bionic hand exhibited exceptional dexterity and robust grasping capabilities, demonstrating significant potential for robotic manipulation tasks.

Figures (13)

• Figure 1: The IRMV Hand
• Figure 2: (a) Structure of MCP joint incorporating spring pre-tensioning mechanisms to compensate tendon slack (springs mounted at tendon termini). Dashed lines denote extension tendons, solid lines indicate flexion tendons; (b) Axial projection of MCP transmission structure, where each pulley module outputs two antagonistic tendons; (c)(e) Simultaneous counterclockwise rotation of dual motors causes synchronous contraction of the left antagonistic tendon pair, generating rightward deflection moment at MCP joint; (d)(f) Antagonistic motor rotation increases tension in solid tendons while decreasing dashed tendon tension, producing adduction moment at MCP joint.
• Figure 3: CAD design of the IRMV Hand. (a) illustrates the kinematic structure of the IRMV Hand, which possesses 15 DOF, similar to the DOF of a human hand. The DIP joint's DOF can be configured as either fixed or active based on requirements. (b) shows the overall structure of the IRMV Hand, with dimensions of approximately 100mm × 100mm × 265mm and a finger width of 20mm, closely resembling the size of an adult human hand. The forearm section houses five motors for driving grasping functions, while the palm section incorporates ten motors for assisting operational tasks.
• Figure 4: (a) Kinematic actuation of the PIP joint is driven by motor units located in the forearm compartment, achieving low-friction tendon force transmission via PTFE-lined conduits; (b) Tendon routing configuration for finger flexion and extension motions, generating directed moments at the MCP2 and PIP joints respectively
• Figure 5: Hardware system of the IRMV Hand.