A Low-Cost Orthosis Using a Compliant Spring Mechanism for Post-Stroke Hand Rehabilitation

Restoration of basic hand functions (grasping and object manipulation) is one of the goals of post-stroke rehabilitation therapy. In this study, an exoskeleton device that facilitates repetitive active training of fingers involving flexion and extension is proposed. The proposed rehabilitation device features a Remote Centre of Motion (RCM) achieved by fitting the mechanical axis of rotation to the joints through adequately-positioned compliant elements. The device also uses an underactuated mechanism where the compliant elements are to perform three rotational motions of the finger joints to achieve complete finger flexion, extension and slight rotation with the use of a single actuator. The use of a single actuator, and the monolithic structure of the compliant elements enables the device to be compact, light-weight and very portable in nature. Due to its lightweight and portability, the device can hypothetically be used both in the hospitals and also at home to support Activities of Daily Living (ADL). In this paper, the mechanical structure of the device is introduced, a fabricated prototype presented and the advantages of the device over similar and other state of the art rehabilitation devices are discussed.