A Brief Review on Robotic Exoskeletons for Upper Extremity Rehabilitation to Find the Gap between Research Porotype and Commercial Type

Abstract

The number of disabled individuals due to stroke is increasing day by day and is projected to continue increasing at an alarming rate in United States. But the current amount of health professionals in physical therapy is inadequate to provide rehabilitation to these large groups. From early 1990s, researchers have been trying to develop an easy and feasible solution to this problem and lot of assistive devices both end effector type or exoskeleton type have been developed till to date. However, only a few of them have been commercialized and are being used in rehabilitation of post-stroke patients. Making the use of exoskeletons and other devices to regain lost motor function is rare. Providing therapy to this large group is quite impossible without commercializing of exoskeleton. This has motivated the authors to make a literature review and figure the reasons out that need to be solved to bridge the gap between research prototype to commercial version. This paper covers the necessity of incorporating robotic devices in rehabilitation, a brief description of existing devices particularly upper limb exoskeletons, their hardware limitations, and control issues. Our review shows that there are significant flaws in hardware design and developing control algorithm of exoskeletons to be available in rehabilitation program.

A Review on Design of Upper Limb Exoskeletons

“…Hydraulic actuators are powered by hydraulic pressure. They can produce greater torque as compared to the electric and pneumatic actuators [11]. The system is relatively complex considering the maintenance of pressurized oil under pressure to prevent leakage.…”

“…In the last two decades, the upper-limb exoskeletons used for services and rehabilitation have attracted a lot of attention from the biomedical and engineering sectors. The technology is becoming important as a potential solution for physically weak or disabled people [11]. Systems have been developed to improve the performance and strength of the wearer, e.g., Ekos Vest [2] and FORTIS [12].…”

“…A study on the development of upper-limb hybrid exoskeletons in combination with the functional electrical stimulation (FES) was reported by Stewart et al [16], which mainly focused on post-stroke rehabilitation and patient monitoring. Islam et al [11] made a review to identify the technological gap between the commercially available robotic exoskeletons and research prototypes used for post-stroke rehabilitation. However, given the extensive studies on the upper-limb exoskeletons, very few articles have reported the exoskeleton's design addressing complex anatomical movements at the shoulder and wrist joints of the arm and hand as a whole (general hand opening and closing).…”

Introductory Chapter: Medical Robots in Surgery and Rehabilitation

“…Several upper extremity robotic rehabilitation devices have been designed since the 1990s. Some important points taken into account while designing robotic rehabilitation devices can be summarized as cheap, low mass, compactness, safe operation, easy wearing, portability, and home use [8]. Some recent upper extremity robotic rehabilitation devices can be described as follows: Mit-Manus [9], Reharob [10], Armin [11], Caden-7 [12], Medarm [13], Esa human arm exoskeleton [14], L-exos [15], Armor [16], and Sarcos Master Arm [17].…”

Upper-Limb Exoskeletons for Stroke Rehabilitation

“…Pneumatic and hydraulic, due to their nature, are inherently safe and compliant, thus suitable for applications involving human-robot interaction. These actuators have been widely tested in exoskeletons in the past years, however due to their power consumption, low efficiency and limited control bandwidth, they did not find great consensus [10]. On the other side, due to their ability to produce large amount of torque, their commercial availability and their intrinsic precision in controlling motion, current solutions mainly implement stiff joints actuated by electric motors.…”