Enhancing Voluntary Motion with Modular, Backdrivable, Powered Hip and Knee Orthoses

Area of Science:

• Rehabilitation Engineering
• Biomechanics
• Assistive Technology

Background:

• Mobility disabilities present diverse challenges, necessitating adaptable assistive devices.
• Modular, partial-assist lower-limb exoskeletons are crucial for supporting heterogeneous populations.

Purpose of the Study:

• Introduce the Modular Backdrivable Lower-limb Unloading Exoskeleton (M-BLUE).
• Evaluate M-BLUE's ability to reduce muscular effort in able-bodied individuals during a lifting task.

Main Methods:

• Developed M-BLUE with high torque, low impedance actuators on modified commercial orthoses.
• Performed benchtop system identification for actuator characterization.
• Conducted human subject experiments with unilateral M-BLUE configurations (hip, knee, hip-knee) and a gravity compensation controller.

Main Results:

• Verified backdrivable properties and achieved torque prediction within ±0.4 Nm.
• Demonstrated significant reductions in muscle EMG readings across primary squat musculature.
• Observed decreased mean muscular effort and peak muscle activation during lifting and lowering tasks.

Conclusions:

• M-BLUE shows potential in reducing muscular effort and fatigue during lifting tasks.
• Results support M-BLUE's application for individuals with mobility impairments.
• Future work includes bilateral configurations and ankle assistance expansion.