ForceArm: A Wearable Pneumatic Gel Muscle (PGM)-Based Assistive Suit for the Upper Limb

Abstract

This paper discusses the effects of using a pneumatic gel muscle (PGM)-based assistive suit called ForceArm, to augment the arm of elderly patients with weak muscles. The ForceArm comprises of PGMs to support four degrees of freedom of the human arm. The suit was evaluated using surface electromyographical (sEMG) signals to identify the muscle unloading effects in the forearm of elderly subjects. Muscle unloading effects were also examined in healthy subjects while performing elbow and shoulder flexion with and without ForceArm. Additionally, the motor ability of the upper extremity of two elderly subjects was evaluated through palm position and velocity data over two months while they participated in a gaming task. One of the subjects performed the task with assistance throughout, while the other subject performed the task without assistance. The results of sEMG data show that, on average, muscle unloading was achieved for all motions (except shoulder flexion) in assisted condition as compared to non-assisted condition in at least one out of four associated muscles. For the gaming task, if we consider the average values of the rates of change of scores (except hand-path ratio score) used to study the trend of the data, the subject who was provided with ForceArm augmentation showed better improvement in performance over time.