Trajectory Modulation for Impact Reducing of Lower-Limb Exoskeletons

Area of Science:

• Robotics
• Biomechanics
• Rehabilitation Engineering

Background:

• Lower-limb exoskeletons aid walking assistance and rehabilitation for paraplegic patients.
• Excessive foot-ground impacts during exoskeleton-assisted walking cause discomfort and potential injury.

Purpose of the Study:

• To propose and validate an optimized knee trajectory modulation (OKTM) method for reducing foot-ground impact forces.
• To introduce a complementary hip trajectory modulation (HTM) to address torso pitch deflections.

Main Methods:

• Developed an optimized knee trajectory modulation (OKTM) using a parameter-optimizing spring-damping system.
• Implemented a hip trajectory modulation (HTM) to counteract torso pitch.
• Validated the OKTM and HTM approach through simulations and experimental testing.

Main Results:

• The OKTM effectively reduced the peak ground reaction force (PGRF).
• The HTM successfully compensated for torso pitch deflections caused by OKTM.
• The proposed methods require no bulky mechanical structures and offer adaptive parameter adjustment.

Conclusions:

• The optimized knee trajectory modulation (OKTM) is an effective strategy for reducing foot-ground impacts in lower-limb exoskeletons.
• The adaptive, non-bulky nature of OKTM and HTM offers a significant advantage over traditional mechanical solutions.