A Sensorless, Inherently Compliant Anthropomorphic Musculoskeletal Hand Driven by Electrohydraulic Actuators

2026-03-25

AI Summary

This work proposes a humanoid tendon-driven robotic hand powered by remotely located Peano-HASEL electrohydraulic soft actuators to achieve safe and dexterous manipulation in unstructured environments. By relocating the actuators to the forearm, electrical components are isolated from the hand, enhancing safety, while a 1:2 pulley mechanism amplifies tendon displacement for improved range of motion. Leveraging the intrinsic force-limiting behavior of HASEL actuators and real-time actuator current signals, the system enables self-sensing grasp control without external force or position sensors, facilitating contact detection and closed-loop manipulation. The platform successfully executes diverse grasping tasks, including damage-free handling of extremely fragile objects such as paper balloons, demonstrating high dexterity and inherent safety.

Technology Category

• Intelligent Robots: Manipulation
• Humans and AI: Human-Aware Planning and Behavior Prediction
• Natural Language Processing: Safety and Robustness

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Economics, Online Markets and Human Computation: The sharing economy

Abstract

Robotic manipulation in unstructured environments requires end-effectors that combine high kinematic dexterity with physical compliance. While traditional rigid hands rely on complex external sensors for safe interaction, electrohydraulic actuators offer a promising alternative. This paper presents the design, control, and evaluation of a novel musculoskeletal robotic hand architecture powered entirely by remote Peano-HASEL actuators, specifically optimized for safe manipulation. By relocating the actuators to the forearm, we functionally isolate the grasping interface from electrical hazards while maintaining a slim, human-like profile. To address the inherently limited linear contraction of these soft actuators, we integrate a 1:2 pulley routing mechanism that mechanically amplifies tendon displacement. The resulting system prioritizes compliant interaction over high payload capacity, leveraging the intrinsic force-limiting characteristics of the actuators to provide a high level of inherent safety. Furthermore, this physical safety is augmented by the self-sensing nature of the HASEL actuators. By simply monitoring the operating current, we achieve real-time grasp detection and closed-loop contact-aware control without relying on external force transducers or encoders. Experimental results validate the system's dexterity and inherent safety, demonstrating the successful execution of various grasp taxonomies and the non-destructive grasping of highly fragile objects, such as a paper balloon. These findings highlight a significant step toward simplified, inherently compliant soft robotic manipulation.

Problem

• robotic manipulation
• inherent compliance
• sensorless control
• soft actuators
• unstructured environments

Innovation

• electrohydraulic actuators
• inherent compliance
• self-sensing
• musculoskeletal hand
• sensorless control