The use of wearable exoskeletons for assisting patients with impaired motor function is nothing new. However, a new device may change how hand exoskeletons work forever.
Created in the Evolution Innovation Laboratory (http://bioeng.nus.edu.sg/eilab/) at the National University of Singapore by Dr Raye Yeow and Mr Yap Hongkai, the wearable robotic device called ExoGlove is an exoskeleton device, but with a twist. it does not rely on a hard body like most exoskeletons do. Instead, it makes use of a material that is soft, and depends on customizable pneumatic actuators to get its job done.
The biggest advantage of ExoGlove over other similar exoskeletons used for hand rehabilitation is that it uses variable stiffness. Most actuators used in exoskeleton devices, like Fiber-Reinforced actuator and PneuNets actuator, exhibit configuration that is circular, and are not able to conform to the motions of the human hand accurately. ExoGlove, on the other hand, features actuator which can make adjustments based on the dimensions of the fingers.
Owing to its ability to nicely conform to the bending movements of human fingers, ExoGlove can be used to facilitate activities of daily living (ADL), as well as to take rehabilitation to the next level. In its ADL mode it can perform gestures like pinching and grasping, while in its rehabilitation mode it can fuel repetitive movements to attain continuous exercises of passive motion. With its actuator being able to bend at the joining, instead of at segments, the exoskeleton encourages hand movements that are natural. It even allows for stiffness variation based on the type of exercise performed, ranging from straight fist to table top.
While this glove – featuring Velcro straps – certainly has huge potential to contribute positively in the medical field during the coming years, it has its own challenges to tackle before it can be tested on patients. The first challenge is finding a material which is more reliable than its current hyper elastic material. As hyper elastic material is prone to facing hysteresis, gradual decline in performance, budging in the long run, and eventual failure can be expected. Other than that, user safety is also at stake, as the present prototype has no feature to detect a system failure and stop the operation of the glove. Equipping the system with different feedback systems and making a single actuator capable of assisting more than one exercise are two other big roadblocks that exist.
The challenges are real, but once they are tackled, ExoGlove will not only be able to provide better weight-to-power ratio, but also ensure safer robot-human interaction.