Effects of Air Gaps on the Output Force Density in COMSOL Simulations of Biomimetic Artificial Muscles

Abstract

This paper presents a novel approach to enhancing the performance of artificial muscle fibers by incorporating air gaps within the bulk dielectric material. Building on previous models, the COMSOL simulation was developed to investigate the effects of varying the inner ligament width (‘w3’) and air gap width (‘w2’) on force production. Results indicated that an air gap width of 50 µm is optimal, balancing improved force output with manufacturability constraints. A longitudinal array sweep was conducted to determine force density saturation in long fiber arrays, comparing the gap model with a traditional non-gap model. The gap model demonstrated superior performance, achieving higher force densities and better energy efficiency. The inclusion of air gaps reduced overall weight, enhanced flexibility, and improved the force-to-weight ratio, making the design particularly suitable for applications in prosthetics, exoskeletons, and soft robotics. These findings suggest that the air gap design represents a significant advancement in artificial muscle technology, offering a practical and efficient solution for various biomedical and robotic applications.

Keywords

• actuator
• muscle
• fiber
• biomimetic
• electrostatic
• force