Muscle as a tunable material: implications for achieving muscle-like function in robotic prosthetic devices

Area of Science:

• Biomedical Engineering
• Biomechanics
• Robotics

Background:

• Prosthetic devices aim to replicate biological limb function, but current designs fall short of ideal performance.
• Lower extremity prostheses, both passive and active, attempt to mimic the ankle joint's dynamic function crucial for locomotion.
• Existing prostheses lack adaptive control, failing to adjust to varying gait conditions like speed changes or inclines.

Purpose of the Study:

• To investigate the limitations of current prosthetic control systems.
• To explore a new paradigm of 'muscle as a tunable material' for prosthetic design.
• To inspire the development of more adaptive and versatile prosthetic limbs.

Main Methods:

• Review of current prosthetic technology and control algorithms.
• Analysis of biological muscle function, focusing on neural activation's role in tuning stiffness and damping.
• Conceptual exploration of applying biological muscle principles to prosthetic engineering.

Main Results:

• Passive prostheses do not normalize energetics due to a lack of variable ankle impedance.
• Robotic prostheses show potential but face challenges in adaptive and versatile control.
• Current control algorithms cannot adapt to diverse gait requirements.

Conclusions:

• A deeper understanding of muscle adaptability, viewing it as a tunable material, can inform better prosthetic design.
• Collaboration between biologists and engineers is crucial for advancing prosthetic capabilities.
• Future prostheses could potentially surpass biological limb function across various conditions by emulating muscle's adaptive properties.