Engineering Synthetic Soft Tissue for Accurate Human-Exoskeleton Interaction Testing.

Area of Science:

• Wearable robotics
• Biomechanics
• Materials science

Background:

• Assessing physical human-exoskeletons interaction (pHEI) is crucial for developing assistive wearable robots.
• Early-stage development faces safety and ethical challenges with human testing.
• Existing robotic leg models lack realistic soft-tissue simulation for pHEI.

Purpose of the Study:

• To identify synthetic soft tissue simulants that enhance the fidelity of robotic leg models.
• To develop a novel testing methodology for characterizing soft tissue mechanical properties under compressive and shear stresses.
• To benchmark the biomechanical behavior of a robotic leg with enhanced soft tissue simulation against human subjects.

Main Methods:

• Developed an active dummy leg, the Leg Replica, for pHEI assessment.
• Proposed a novel mechanical testing methodology for soft tissue characterization under compression and shear.
• Tested three silicone materials with varying properties on the Leg Replica and compared results with 10 human subjects.

Main Results:

• A 3 cm thick platinum-catalyzed silicone material demonstrated mechanical behavior comparable to human soft tissue under compressive and shear stresses.
• The proposed testing methodology provided objective data for comparing robotic and human tissue responses.
• The enhanced Leg Replica with the selected silicone simulant showed improved realism in mimicking human leg biomechanics.

Conclusions:

• Synthetic soft tissue simulants can significantly improve the realism of robotic leg models for pHEI.
• The developed testing methodology offers a reliable approach for evaluating soft tissue mechanical properties in wearable robotics.
• The enhanced Leg Replica provides a safer and more ethical platform for testing lower limb exoskeleton development.