A Review on Design of Upper Limb Exoskeletons

Abstract

Exoskeleton robotics has ushered in a new era of modern neuromuscular rehabilitation engineering and assistive technology research. The technology promises to improve the upper-limb functionalities required for performing activities of daily living. The exoskeleton technology is evolving quickly but still needs interdisciplinary research to solve technical challenges, e.g., kinematic compatibility and development of effective human–robot interaction. In this paper, the recent development in upper-limb exoskeletons is reviewed. The key challenges involved in the development of assistive exoskeletons are highlighted by comparing available solutions. This paper provides a general classification, comparisons, and overview of the mechatronic designs of upper-limb exoskeletons. In addition, a brief overview of the control modalities for upper-limb exoskeletons is also presented in this paper. A discussion on the future directions of research is included.

An Exoneuromusculoskeleton for Self-Help Upper Limb Rehabilitation After Stroke

“…23 Hydraulic systems are powered by hydraulic pressure, and able to produce greater torque compared with the actuators in cable and pneumatic systems. 11,23,24 However, few hydraulic systems have been developed for upper limb, because they are relatively heavy and complex in the design, requiring additional space to accommodate the fluid and to prevent leakages under pressure. 11,16,23 In contrast, pneumatic systems (pneumatic muscles) are the most commonly adopted actuation for the upper limb.…”

“…11,23,24 However, few hydraulic systems have been developed for upper limb, because they are relatively heavy and complex in the design, requiring additional space to accommodate the fluid and to prevent leakages under pressure. 11,16,23 In contrast, pneumatic systems (pneumatic muscles) are the most commonly adopted actuation for the upper limb. 21,23 Pneumatic exoskeletons have high torque-to-weight ratios because of the low weight of the wearable part actuated by air.…”

“…11,16,23 In contrast, pneumatic systems (pneumatic muscles) are the most commonly adopted actuation for the upper limb. 21,23 Pneumatic exoskeletons have high torque-to-weight ratios because of the low weight of the wearable part actuated by air. 21,[25][26][27][28][29] However, pneumatic systems are usually bulky and slow in power transmission from pressure to torque during air inflation by compressors for needed air volume and pressure compared with electrical motor actuation in rigid exoskeleton to achieve equivalent mechanical outputs (e.g., joint torque).…”

“…21,[25][26][27][28][29] However, pneumatic systems are usually bulky and slow in power transmission from pressure to torque during air inflation by compressors for needed air volume and pressure compared with electrical motor actuation in rigid exoskeleton to achieve equivalent mechanical outputs (e.g., joint torque). 23,30 Large and high-power compressors connected to the pneumatic muscles constrain these devices for user-independent applications. 21 Thus, a novel lightweight mechanical design is required to achieve optimized body/device integration with fast power transmission, high torque-to-weight ratios, and low-power consumption for user-independent self-help rehabilitation.…”

State-of-the-Art Assistive Powered Upper Limb Exoskeletons for Elderly

“…Numerous review papers have been published on the topic of upper limb exoskeletons for rehabilitation and assistive purposes [14][15][16][17][18][19][20][21][22][23][24][25]. The difference between these published review papers and this paper is that the current paper concentrates mostly on robotic upper limb devices which can be used by old people to perform their ADL, enabling them improving their life quality.…”