Surpassing Nature: How Fiber-Type Artificial Muscles Outperform the Biological

The quest to replicate the capabilities of biological muscles has long fascinated engineers and scientists. These natural actuators exhibit remarkable flexibility and force, making them ideal models for artificial muscle development. A recent review published in Nature delves into the advancements of fiber-type artificial muscles, which not only mimic but now also outperform biological muscles in several aspects.

The Evolution of Fiber-Type Artificial Muscles

Historically, artificial muscles have been created using various materials and methods, like pneumatics, electroactive polymers, and shape memory alloys. However, these approaches often faced challenges in terms of complexity, bulkiness, or limited versatility. Enter fiber-type artificial muscles—higher in flexibility and adaptability, and capable of functioning across multiple actuation modes: tensile, bending, torsional, and isometric. These muscles borrow their structural inspiration from natural muscle fibers, achieving life-like movement through small-scale internal changes that scale up to substantial actuation.

Enhanced Performance Metrics

Notable for surpassing biological muscles in several performance metrics, these fiber-type muscles leverage unique actuation forms. For instance, they achieve impressive torsional speeds up to 11,500 revolutions per minute via heat-powered composites, while demonstrating significant tensile strain rates of up to 8,600% in certain configurations. Moreover, isometric models can achieve contraction stresses over 100 times that of mammalian muscles, showcasing a staggering capability to exert force despite reduced size.

Versatile Applications and Future Prospects

The potential applications for these advanced artificial muscles are vast, spanning from biomedical devices aiding rehabilitation to soft robotics designed for environments where traditional robotics may falter. Smart textiles reacting to environmental changes are also on the horizon. Despite these promising advances, challenges remain in terms of production complexity and material costs. Researchers are actively exploring solutions like self-healing materials and sustainable manufacturing approaches using natural fibers.

Key Takeaways

Fiber-type artificial muscles have marked a revolutionary step in achieving and exceeding the functions of biological muscles, with potential applications across varied industries. As technologies advance, the integration of these muscles in everyday technologies appears imminent. With ongoing research addressing current limitations, we are poised to witness a transformative impact on robotics, human augmentation, and beyond.

More Information:

Ji Hwan Moon et al, Fiber-type artificial muscles for robotic actuation, npj Robotics (2025). DOI: 10.1038/s44182-025-00059-8