Kinematic Study of a Novel Active Knee Exoskeleton for Alleviating Crouch Gait in Individuals with Cerebral Palsy

Abstract

This paper introduces an innovative active knee exoskeleton designed to alleviate crouch gait in individuals with cerebral palsy (CP). Addressing the common manifestation of excessive knee flexion in CP patients, the proposed lower limb exoskeleton (LLE) employs four degrees of freedom for natural movement, featuring a passive hip joint and an active knee joint for both legs. The study delves into forward and inverse kinematics, utilizing Denavit-Hartenberg parameters and transformation matrices, and explores the equations of motion governing human and exoskeleton dynamics. Trajectory planning for the exoskeleton is informed by gait analysis data from a healthy pilot subject obtained through a motion capture system. The research presents a quintic polynomial trajectory equation for seamless motion planning, incorporating knee joint parameters. Validation with motion capture data demonstrates consistent functions in knee position, velocity, and acceleration, aligning with physiological norms. This work contributes to the advancement of assistive technology for CP individuals, laying a foundation for future interventions. © 2024 IEEE.