A Wearable Finger Tremor-Suppression Orthosis Using the PVC Gel Linear Actuator

Tremor is a prevalent neurological disorder that affects individuals of almost all ages and can significantly impede their quality of life and occupational functioning. Wearable medical devices for suppressing tremors, typically low-frequency vibrations ranging between 3 and 12 Hz, are gaining popularity since active vibration absorbers integrated into such devices have demonstrated immediate efficacy and noninvasive nature. How- ever, there are challenges in miniaturizing active absorbers for wearable applications with traditional actuators. To address this problem, here we present a light wearable active finger tremor- suppressing orthosis (AFTO) that consists of a stacked polyvinyl chloride (PVC) gel actuator-based absorber, an inertial measure- ment unit (IMU), and a force sensor. The integrated sensors allow the device to detect tremors and trigger the absorber to suppress vibrations, regardless of whether the fingertip is vibrating in the air or applying tremor force while in contact with an object. A 3D-printed compliant Sarrus-mechanism exoskeleton was used to house the PVC gel stacked actuator, thus minimizing the linear actuator’s swaying while maximizing the effective actuation area. This innovative wearable finger tremor absorption system has the potential for various applications in daily life and occupational contexts, such as stabilizing the finger during grasping, typing, operating surgical instruments, drawing, and other tasks.