Hyperelastic Membrane Actuators: Analysis of Toroidal and Helical Multifunctional Configurations

Area of Science:

• Biomedical Engineering
• Materials Science
• Regenerative Medicine

Background:

• Medical implants require mechanical assistance for tissue regeneration.
• Developing actuators with high axial extension, low pressure operation, modularity, multifunctionality, and load-bearing capacity is challenging.
• Existing actuators often lack shape maintenance, softness, or load resistance.

Purpose of the Study:

• To introduce novel modular actuators (M2H) for enhanced mechanical assistance in tissue regeneration.
• To design and validate actuators combining high axial extension, radial expansion, and load-bearing capabilities.
• To enable anatomically congruent stimulation for therapeutic needs.

Main Methods:

• Development of stacked Hyperelastic Ballooning Membrane Actuators (HBMAs) in helical and toroidal configurations.
• Integration of a semi-soft exoskeleton to control HBMA expansion and enable axial extension.
• Design, fabrication, numerical simulation, and experimental validation of the M2H-HBMAs.

Main Results:

• M2H-HBMAs achieved axial extensions of up to 41% (helical) and 32% (toroidal) at low pressures (26 and 24 kPa).
• The axial extension module alone demonstrated >170% extension capacity.
• Actuators supported >1 kg axial force without collapse and exhibited independent/simultaneous motion with minimal deformation.

Conclusions:

• M2H-HBMAs successfully overcome limitations of existing hyperexpanding actuators regarding load resistance.
• These novel actuators offer a promising platform for advanced mechanical assistance in tissue regeneration procedures.
• The modular and multifunctional design allows for tailored therapeutic applications.