Case Study and Preliminary Validation of a Parametric, Three-Dimensional Printable Tendon-Driven Biomimetic Hand Exoskeleton

Abstract Portable hand exoskeletons are reaching homes, providing daily assistance to people with hand impairments and enhancing their quality of life. Their design, however, is rarely based on the biomimetics of human finger kinematics, missing the benefits of anatomical tendon pulley-based actuation, such as natural and comfortable movement with efficient force transmission. We present a case study of a portable biomimetic hand exoskeleton system for assistance in grasping and rehabilitation. Components of the exoskeleton are parameterized via computer-aided design (CAD) using human hand dimensions measured at selective locations facilitating easy customization. Easy-to-use voice and manual button input strategies control the exoskeleton. A biomimetic flexor system with passive extension is used. A stiffness adjuster mechanism is provided at a metacarpophalangeal (MCP) joint to make suitable adjustments to the extension force. We evaluate the system with a hemiparetic subject with low grip strength poststroke that occurred a decade ago, showing promising results of high contact forces when grasping a variety of objects. This lightweight exoskeleton could be helpful for people finding difficulties in grasping related activities of daily living due to neurological conditions and/or aging.