A passive T/V-beam absorber architecture for single-axis experimental hand tremor attenuation

Hand tremor is a debilitating motor symptom associated with neurological disorders such as Parkinson's disease and essential tremor (ET). This study presents the design, parameter tuning, and experimental evaluation of a passive mechanical absorber for tremor attenuation based on T- and V-beam configurations. The proposed device is described as an multi-degree-of-freedom-capable architecture because its geometry can accommodate absorber branches oriented in more than one direction; however, the present experimental validation was conducted using a single-axis, 1-DOF mannequin-based tremor simulator. Therefore, the reported data validate single-axis attenuation only and should not be interpreted as full multidirectional wrist validation. The system operates without external power and is intended as a simple passive alternative to active tremor-suppression devices. Experimental validation demonstrated a reduction of up to 85% in steady-state peak-to-peak displacement relative to the uncontrolled condition. The investigated frequency range was 3.0-6.5 Hz, selected because it overlaps the 4-6 Hz range often reported for Parkinsonian rest tremor and extends into the lower-to-mid range commonly observed in ET during postural or kinetic tasks. Key design parameters, including absorber mass, equivalent stiffness, beam-position geometry, and actuator configuration, were selected using a constrained parametric tuning procedure rather than an unconstrained global optimization. Frequency-domain metrics, including power spectral density and transmissibility, are defined to complement the time-domain amplitude-reduction metric and to verify attenuation at the dominant excitation frequency. The results suggest that the double V-beam configuration provides stronger single-axis attenuation than the single-actuator configuration and supports further development toward wearable tremor-management applications.