Kelvin H.L. Heung, Zhiqiang Tang, Leo Ho, Macro Tung
Stroke is the leading cause of disability. Hand rehabilitation devices containing mechanical structures have been introduced to stroke communities for hand function recovery. However, drawbacks exist in their bulkiness that can hinder upper-limb movement and performance of activities of daily life (ADL). Soft robotic hand for rehabilitation have been proposed for aiding in the performance of activities of daily living (ADL). Although existing soft robotic hands can assist with finger flexion, few have addressed finger extension, which is a challenging task for stroke patients due to poststroke spasticity.
We describe the design of a composite actuator, the soft-elastic composite actuator (SECA), to facilitate both finger flexion and extension. A 3D printed double-segmented SECA comprising two serially connected fiber-reinforced actuators with two bottom torque compensating layers is 3D printed. The SECA bends and extends actively by pneumatic actuation, and the torque compensating layers offer an assistive bending moment to configure the bending moment inside the SECA for facilitating extension.
Compared with conventional robotic devices, our 3D-print soft robotic hand can assist patients in performing more hand function tasks for aiding ADL, for example, wringing a towel and gripping a pen. These tasks are difficult to be completed when patients are using the conventional metallic robotic devices because of their bulkiness. The system is controlled by user intention (e.g. muscle activities [EMG]]) to facilitate neuro-rehabilitation. A new task-oriented rehabilitation training program with our design can therefore be potentially introduced to day-care rehabilitation centers for better hand function recovery.