Development and Control of a lower limb power assist exoskeleton robot [abstract]

Abstract

The aim of the project was to develop functional lower limb exoskeletons to enhance human power for providing motion assistance/rehabilitation for physically challenged individuals and/or power assistance for abled-bodied workers. These objectives were achieved by developing three different exoskeletons named Anthro-X, C-JAE, and PPKE. Anthro-X is multi-degrees of freedom (DoF) modular power-assist LEE robot with compatible joint axes to enhance kinematic compliance. It can support all three DoF at the hip joint using a novel articulated mechanism. The polycentric motion of the knee joint is also facilitated using a unique mechanism based on four-bar linkage system. The hip and knee joints are powered by external power supply and others are passively supported. Anthro-X rely on electromyography signals from thigh muscles to generate hip and knee movements. The prototype of Anthro-X was fitted on a male subject to verify the kinematic conformity of mechanisms. Results show that the proposed design can provide both motion and power assistance. C-JAE is a three DoF robotic ankle exoskeleton with compatible joint axes. The device consists of three separate units to achieve triplanar motions. The plantarflexion-dorsiflexion and inversion-eversion are externally powered, whereas internal-external rotation is passively supported. All drive units are located anterior to shank and foot segments to carry out robotic rehabilitation or locomotion assistance for humans having mobility disorders. The results verified that C-JAE can generate desired movement patterns while providing power-assistance. PPKE is a knee exoskeleton with a passive-powering mechanism to provide power assistance during squat lifting. It is designed to capture and store 20% of biomechanical energy dissipated at knee joint during decent phase and return harnessed energy in ascent phase. The proposed system reduced the peak root-mean-square averages of electromyography signals of knee extensor muscles by 40%. Thus, PPKE is energetically autonomous and a suitable device for industrial use.