Without finger function, people with C5-7 spinal cord injury (SCI) regularly utilize wrist extension to passively close the fingers and thumb together for grasping. Wearable assistive grasping devices often focus on this familiar wrist-driven technique to provide additional support and amplify grasp force. Despite recent research advances in modernizing these tools, people with SCI often abandon such wearable assistive devices in the long term. We suspect that the wrist constraints imposed by such devices generate undesirable reach and grasp kinematics. Here we show that using continuous robotic motor assistance to give users more adaptability in their wrist posture prior to wrist-driven grasping reduces task difficulty and perceived exertion. Our results demonstrate that more free wrist mobility allows users to select comfortable and natural postures depending on task needs, which improves the versatility of the assistive grasping device for easier use across different hand poses in the arm's workspace. This behavior holds the potential to improve ease of use and desirability of future device designs through new modes of combining both body-power and robotic automation.

翻译：对于C5-7脊髓损伤（SCI）患者而言，由于手指功能丧失，他们通常利用腕部伸展来被动闭合手指与拇指以实现抓握。可穿戴辅助抓握装置常聚焦于这种熟悉的腕驱动技术，以提供额外支持并增强抓握力。尽管近期研究在现代化这些工具方面取得了进展，但SCI患者长期来看常会弃用此类可穿戴辅助设备。我们推测，这类设备施加的腕部约束会产生不良的伸展与抓握运动学。本文研究表明，通过连续机器人电机辅助使用户在腕驱动抓握前获得更灵活的腕部姿态适应性，可降低任务难度与感知用力。我们的结果表明，更自由的腕部活动度使用户能根据任务需求选择舒适自然的姿态，从而提升辅助抓握装置在手臂工作空间内适应不同手部姿势的通用性，使跨任务操作更为简便。这一行为模式有望通过结合人体动力与机器人自动化的新模式，提升未来设备设计的易用性与吸引力。