ScholarWorks@숙명여자대학교

초록

Hand exoskeletons are widely studied as assistive devices for supporting finger motion in rehabilitation and functional tasks. In several existing systems, assistance levels are primarily regulated through motor inputs or control strategies, which can limit the intuitive adjustment of assistance characteristics and underutilize the role of mechanical structure. This study addresses this challenge by presenting a hand exoskeleton that modulates joint torque and angular velocity through a mechanically adjustable linkage, enabling assistance characteristics to be reconfigured without altering the motor input. By changing the length of a motor-driven proximal link, the effective moment arm is directly modified, allowing a predictable modulation of force and speed under identical actuator conditions. Kinematic and static analyses show that increasing the link length amplifies the transmitted fingertip force, whereas shortening it increases joint angular velocity, reflecting the inherent geometric force–velocity tradeoff of the mechanism. Experimental results confirmed that the fingertip force increased from 4.59 to 7.58 N (65% increase) across the tested link-length range, whereas the metacarpophalangeal joint angular velocity decreased from 0.96 to 0.63 rad/s (34% reduction). Electromyography measurements further indicated a 16% reduction in muscle activation during a 12 N grip task when approximately 6 N of mechanical assistance was provided. These findings demonstrate that geometry-driven assistance modulation offers a practical pathway toward adaptable, task-specific, and user-tailorable hand exoskeletons for rehabilitation and functional support.

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