Novel Method for Setting Population-Specific Joint Torque Assistance Requirements with Applications to Exoskeleton...

Area of Science:

• Biomechanics
• Robotics
• Assistive Technology

Background:

• Wearable robotic devices require accurate assistance calculations for effectiveness.
• Existing methods often focus on task-specific kinematics and kinetics, not population-level capabilities.
• Older adults often experience physical deficits that necessitate tailored assistive solutions.

Purpose of the Study:

• To present a novel methodology for calculating assistance requirements in wearable robotic devices.
• To determine population-level physical capability deficits for designing assistive technology.
• To demonstrate the method's application to lower limb joints in older adults.

Main Methods:

• Utilizing Maximum Voluntary Contraction (MVC) measurements.
• Calculating population-level assistance needs by comparing a target population to a reference population.
• Identifying a torque deficit (20-25%) for setting assistive torque requirements, distinct from providing 100% of peak torque.

Main Results:

• The proposed method quantifies assistance requirements based on population physical capabilities, not just task specifics.
• A consistent torque deficit of 20-25% was identified for the studied population and joints.
• Torque deficit is presented as a function of joint velocity and angle, enabling tailored actuator design.

Conclusions:

• The novel MVC-based methodology provides a more accurate approach to calculating assistance for wearable robots.
• Addressing identified torque deficits is essential for effective design of assistive devices, particularly for older adults.
• The velocity and angle-dependent torque deficit allows for optimized design of actuators and transmissions in future assistive wearable devices.