Upper Arm Exoskeletons-What specifications will meet users’ acceptability?
Authors: Dubey, V. and Manna, SK
Editors: Daniel G Fisher
Publisher: Nova Publishers, New York
There have been many upper arm exoskeletons developed in the last two decades however none of these have met the expectations of the real users. Most of these designs did not go beyond the laboratory environment and were mainly used either as a research tool or as experimental devices for a very specific application. The majority of these devices were platform-based that was one of the main inhibiting factors why users found such devices too cumbersome to use. Even some of the portable arm exoskeletons did not find much favourable acceptance amongst the user groups because they were too heavy or difficult to put on and operate. This opens up a question, what specifications of upper arm exoskeletons will meet users’ acceptability? This article presents a systematic review of upper arm exoskeletons to find out under what clinical conditions use of such devices may be beneficial, what could be the technical requirements and what user interface must be provided to enhance their acceptability. This paper looks into all major aspects of design related issues of upper arm exoskeleton that existed and the challenges ahead to overcome from technical as well as clinical application point of view. Whether arm exoskeletons can be used for stroke patients, Parkinson’s or patients with weak musculature in assistive mode or for rehabilitation training? Also for those patients who suffer from different neuromuscular disorders have stiff muscles resulting in arm spasticity that doesn’t allow free movement of the joint therefore the exoskeleton design should be adaptable to such clinical needs as well. The physiological parameter should be set as a standard for measuring patient status as the rehabilitation progresses and for bio-feedback. On the technological aspects the design should considers arm’s degrees of freedom, dependency of joints and control regime to justify the optimal design performance. It should be a portable system with active and passive joints with gravity compensation provision to have low energy consumption. The type of actuator selection is one of the important criteria for the acceptability of such devices. It must also consider reconfiguration of the exoskeleton for misalignment, singularity, redundancy in design and weight. There are a large number of sophisticated control algorithms existing but most of them are not adaptive to safety measures and for the ease of operation. In addition to the above, the design must also consider vitally important user interface particularly with the advent of inexpensive electronics gadgets such as Mayo Armband, Google glasses, Eye Tracking systems and Kinect for motivating user rehabilitation.