Jamming Enabled Variable Stiffness Wrist Exoskeleton for Tremor Suppression

Parkinson's disease is a chronic disorder that affects the central nervous system of patients. It affects millions of aging populations around the world every year. Approximately 80% of Parkinson's disease patients suffer from tremors which significantly reduce their life quality. In this study, we present a variable stiffness wrist exoskeleton (VSW-Exo) that is lightweight (less than 300 g on the wrist) and can effectively suppress wrist tremors in all three degrees of freedom. The functioning material of the variable stiffness unit is a novel chain mail-like structured fabric whose stiffness can be pneumatically controlled over a wide range under the jamming transition. Bending and Torsion tests are performed to characterize the VSW-Exo's damping force and torque. To evaluate the VSW-Exo's performance on human bodies, we devise vibration experiments to evaluate the prototype's performance on tremor suppression. The testing results show that our VSW-Exo's tremor suppression efficiency can reach up from 64.11 +/- 10.92% to 67.24 +/- 6.74%. Compared to other tremor suppression devices, our VSW-Exo can provide enough damping forces and torques to suppress tremors in all 3 directions with high efficiency and low weight on the wrist.

Automated summary

This study presents a lightweight variable stiffness wrist exoskeleton (VSW-Exo) that can effectively suppress wrist tremors in all three degrees of freedom for Parkinson's disease patients. By air controlling the stiffness of the material, the exoskeleton reduces tremors in the wrist. Experimental results show that the tremor suppression efficiency of the VSW-Exo can reach from 64.11% to 67.24%.