A Helping Hand: Soft Orthosis with Integrated Optical Strain Sensors and EMG Control

Human fingers and hands are frequently injured because they are delicate, complex, and used constantly. More than 3 million people in the United States suffer from hand or forearm disabilities [1], and, worldwide, hand injuries account for one-third of all work injuries [2]. Due to the importance of hands and the prevalence of hand issues, there is an increasing effort toward developing hand orthotics. These efforts have resulted in active hand orthoses that have been used for rehabilitation training and restoring partial hand function [3]. To ensure safety and to reduce control complexity, some orthoses use mechanical compliances [4], [5] such as underactuated linkages [6] or low-stiffness materials and structures (e.g., rubbers and flexible wires) [7], [8]-[11]. The orthoses made of elastomeric materials tend to be more comfortable, perhaps because their low elastic modulus (10 kPa <; G' <; 1 MPa) [12] is similar to that of human skin (~100 kPa) [13].