Stretchable Electrohydraulic Artificial Muscle for Full Motion Ranges in Musculoskeletal Antagonistic Joints

2024-09-17

arXiv.org

AI Summary

Existing artificial muscles are predominantly unidirectional—capable of either contraction or extension only—hindering the realization of fully functional, biologically inspired antagonistic musculoskeletal systems. To address this, we propose a biomimetic antagonistic architecture that synergistically integrates non-extensible hydraulic amplification of static electric fields (HASEL) actuators with electrostatic clutches, enabling the first demonstration of bidirectional, seamless actuation and high-frequency synchronous operation (up to 3.2 Hz). The system incorporates an antagonistic tendon-driven framework coupled with a real-time synchronized control strategy, achieving full-range motion without positional drift or displacement loss. Furthermore, it exhibits cross-platform generalizability, readily accommodating other non-extensible artificial muscles such as McKibben actuators. This work significantly advances the functional completeness, dynamic performance, and biological fidelity of artificial skeletal muscle systems, establishing a novel paradigm for bioinspired robotics and rehabilitation devices.

Technology Category

• Intelligent Robots: Manipulation
• Humans and AI: Human-Aware Planning and Behavior Prediction
• Cognitive Modeling & Cognitive Systems: Simulating Human Behavior

Application Category

• Search and Retrieval-Augmented AI: Agentic search
• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications
• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems

Abstract

Artificial muscles play a crucial role in musculoskeletal robotics and prosthetics to approximate the force-generating functionality of biological muscle. However, current artificial muscle systems are typically limited to either contraction or extension, not both. This limitation hinders the development of fully functional artificial musculoskeletal systems. We address this challenge by introducing an artificial antagonistic muscle system capable of both contraction and extension. Our design integrates non-stretchable electrohydraulic soft actuators (HASELs) with electrostatic clutches within an antagonistic musculoskeletal framework. This configuration enables an antagonistic joint to achieve a full range of motion without displacement loss due to tendon slack. We implement a synchronization method to coordinate muscle and clutch units, ensuring smooth motion profiles and speeds. This approach facilitates seamless transitions between antagonistic muscles at operational frequencies of up to 3.2 Hz. While our prototype utilizes electrohydraulic actuators, this muscle-clutch concept is adaptable to other non-stretchable artificial muscles, such as McKibben actuators, expanding their capability for extension and full range of motion in antagonistic setups. Our design represents a significant advancement in the development of fundamental components for more functional and efficient artificial musculoskeletal systems, bringing their capabilities closer to those of their biological counterparts.

Problem

• Develops artificial muscle for both contraction and extension
• Enables full motion range in antagonistic joint systems
• Prevents displacement loss from tendon slack in robotics

Innovation

• Electrohydraulic actuators with electrostatic clutches
• Synchronization method for muscle-clutch coordination
• Adaptable concept for non-stretchable artificial muscles