Wearable Hand Exoskeleton for Activities of Daily Living

Hand impairment due to damage in nerve endings and musculature fibers in patients with spinal cord injury and brachial plexus injury has brought upon many difficulties in performing activities of daily living (ADL). This paper presents the design of wearable hand exoskeleton to tackle the problems faced by these patients. The prototype is made of soft wearable glove that is comfortable and lightweight. It also uses Bowden cable and a cable driven mechanism to help the user to flex and extend his/her fingers. To minimize physical constraints, a 3D printed control unit, which houses the controller, DC motors, battery pack and the actuation unit, is designed to be worn around the user's waist. This unit weights approximately 500 g, thus can be suitable for daily use. A series of experiments was conducted to examine the viability of this design and its performance in grasping objects with different shapes and sizes. The results were satisfactory. The hand exoskeleton can produce an average force of 30 N at each fingertip, resulting in a force-to-weight ratio of 0.05 N/g. Moreover, with the use of four 800 mm Bowden cables, the prototype has a reachability of approximately 750 mm while in standing position. Grasping test conducted on various objects such as water bottle, cup, apple and pen further demonstrated the capability of the proposed design for daily use.