A wearable tremor-suppression orthosis

The Viscous Beam is a wearable tremor-suppression orthosis that applies vis cous resistance to motion of the wrist in flexion and extension, The orthos is reduces tremor amplitude and is small enough to be worn under the sleeve of a shirt. Hand and forearm cuffs couple the damper to the user. The cuff s permit full thumb and finger motion, wrist flexion and extension, and for earm pronation and supination. Damping is provided by a constrained-layer-damping (CLD) system, distinct i n that it can damp large rotary deflections through a small bending radius. A bending-plate transmission linearly converts wrist extension/flexion to rectilinear translation within the damper. Bending deformation of two plate s held a fixed distance apart within the transmission results in relative d isplacement along the lengths of the plates. A viscous fluid incorporated b etween the plates provides shear damping. Silicone fluids with viscosities as high as 10 million centistokes (cS) and shear layers as thin as 0.76 mm have been tested. With these parameter values, damping constants as high as 2.0x10(-3) N-m/(degrees/s) have been measured. This testing was conducted with strain rates as high as 4,580 degrees/s. The elastic stiffness of this beam was measured to be 4.1x10(-2) N-m/degrees.