Towards the Development of Dynamic Hand Orthosis Without Conventional Joints.

Abstract

The human hand is an exceptionally complex anatomical structure with 31 degrees of freedom. In the development of dynamic wrist-hand orthoses, the wrist's multiaxial mobility is of particular interest. To accurately replicate these natural movements, a promising approach is the use of compliant tensegrity structures. Tensegrity structures allow pivot points and axes of rotation to align with anatomical positions, enabling unrestricted mobility in all directions without conventional joints. Additionally, they permit customized movement restrictions based on therapeutic needs. The orthosis's minimalist, lightweight design ensures both effective joint stabilization and free access to key injured regions. Customizing each orthosis to the patient's unique anatomy and functional needs is crucial to prevent unnecessary strain from improper positioning. The positioning of the orthosis is directly linked to the forces applied to the wrist while using. A precise understanding of the behavior of the orthosis and its influence on the wrist forces present is therefore essential. This work explores key aspects of tensegrity-based orthosis development, emphasizing accurate 3D scanning of hand anatomy, initial experimental measurements, and simulated calculations. The proposed methodology provides a solid foundation for the design of initial prototypes of tensegrity-based hand orthoses.