Modeling and Simulation of a Lower Extremity Powered Exoskeleton

Area of Science:

• Biomechanics
• Robotics
• Rehabilitation Engineering

Background:

• Lower extremity powered exoskeletons (LEPEs) enable individuals with spinal cord injury (SCI) to stand and walk.
• Current LEPEs often have slow walking speeds and can cause user fatigue, indicating a need for design improvements.

Purpose of the Study:

• To develop and validate virtual models for simulating walking with the ARKE exoskeleton.
• To utilize virtual prototyping for cost-effective enhancement of LEPE design.

Main Methods:

• Developed two musculoskeletal models simulating walking with the ARKE exoskeleton.
• Model 1: Driven by kinematic data from 30 able-bodied participants (0.2-0.8 m/s).
• Model 2: Incorporated upper limb crutches and used 3-D marker data from 5 SCI participants.

Main Results:

• Both models accurately predicted ground reaction forces (GRF) across various walking speeds.
• Strong correlations (>0.90) observed for vertical GRF.
• Weakest correlations (<0.35) for root-mean-square error (RMSE) and mediolateral center of pressure trajectory.

Conclusions:

• Validated musculoskeletal models support the optimization of LEPE joint mechanics.
• The findings facilitate improved design of lower extremity powered exoskeletons for enhanced user mobility and reduced fatigue.