Development and Adaptive Fuzzy Control of a Walking Robotic Exoskeleton for Passive Body Weigh Support

This paper describes a novel development of a lower limber exoskeleton for physical assistance. The developed exoskeleton is a motorized leg device having a total of 6 DOFs with hip, knee and ankle actuated in the sagittal plane. The exoskeleton applies forces and learns the impedance parameters of both robot and human. An adaptive control scheme by incorporated fuzzy control approaches into exoskeleton system is developed to help the leg movement on a desired periodic trajectory and handle periodic uncertainties with known periods. The proposed control approach does not require a muscle model and can be proven to yield asymptotic stability for a nonlinear muscle model and an exoskeleton model in the presence of bounded nonlinear disturbances. The performance of the controller is demonstrated through closed-loop experiments on human subjects.