Design and Sensor Based Evaluation of Custom-Fit Coupling Interfaces for Lower Limb Exoskeletons: A Pilot Study

Area of Science:

• Biomechanics
• Human-Robot Interaction
• Wearable Technology

Background:

• Wearable lower limb exoskeletons are increasingly popular for gait and posture assistance.
• Undesirable physical human-robot interactions (pHRI) at the coupling interface pose risks like skin and musculoskeletal injuries.
• Current research lacks standardized metrics and frameworks for analyzing interface interactions, hindering design guidelines.

Purpose of the Study:

• To compare custom-fit single-user interfaces with generic multi-user interfaces for lower limb exoskeletons.
• To evaluate established and novel pressure-related measures to differentiate interface designs.
• To establish custom-fit interfaces as a baseline for evaluating coupling interface pHRI.

Main Methods:

• Conducted 5-minute overground gait trials with pressure sensors at hip and thigh interfaces.
• Compared custom-fit and generic interfaces using pressure sensors.
• Analyzed pressure measures including average and peak pressure, contact area, and relative movement.

Main Results:

• Custom-fit interfaces demonstrated increased supporting contact area and reduced relative movement compared to generic interfaces.
• Custom thigh interfaces showed notable improvements in performance metrics.
• Pressure analysis metrics effectively differentiated between interface designs and evaluated their performance.

Conclusions:

• Custom-fit interfaces offer significant advantages for lower limb exoskeleton coupling interfaces, enhancing user safety and performance.
• Novel pressure analysis methods are valuable for assessing pHRI and linking improvements to specific interface design characteristics.
• Custom-fit interfaces provide a viable baseline for evaluating and optimizing coupling interface design in wearable robotics.