Andrés-Esperanza Javier, Iserte-Vilar José L, Roda-Casanova Víctor
Department of Mechanical Engineering and Construction, Universitat Jaume I, 12071 Castellón, Spain.
Biomimetics (Basel). 2024 Oct 11;9(10):616. doi: 10.3390/biomimetics9100616.
Stroke often causes neuromotor disabilities, impacting index finger function in daily activities. Due to the role of repetitive, even passive, finger movements in neuromuscular re-education and spasticity control, this study aims to design a rehabilitation exoskeleton based on the pulp pinch movement. The exoskeleton uses an underactuated RML topology with a single degree of mobility, customized from 3D scans of the patient's hand. It consists of eight links, incorporating two consecutive four-bar mechanisms and the third inversion of a crank-slider. A two-stage genetic optimization was applied, first to the location of the intermediate joint between the two four-bar mechanisms and later to the remaining dimensions. A targeted genetic optimization process monitored two quality metrics: average mechanical advantage from extension to flexion, and its variability. By analyzing the relationship between these metrics and key parameters at different synthesis stages, the population evaluated is reduced by up to 96.2%, compared to previous studies for the same problem. This custom-fit exoskeleton uses a small linear actuator to deliver a stable 12.45 N force to the fingertip with near-constant mechanical advantage during flexion. It enables repetitive pulp pinch movements in a flaccid finger, improving rehabilitation consistency and facilitating home-based therapy.
中风常导致神经运动功能障碍，影响食指在日常活动中的功能。由于重复性甚至被动性手指运动在神经肌肉再训练和痉挛控制中的作用，本研究旨在设计一种基于指腹捏取动作的康复外骨骼。该外骨骼采用具有单一运动自由度的欠驱动RML拓扑结构，根据患者手部的3D扫描定制。它由八个连杆组成，包含两个连续的四杆机构和一个曲柄滑块的第三种倒置形式。应用了两阶段遗传优化，首先针对两个四杆机构之间中间关节的位置，然后针对其余尺寸。有针对性的遗传优化过程监测两个质量指标：从伸展到屈曲的平均机械优势及其变异性。通过分析这些指标与不同合成阶段关键参数之间的关系，与之前针对同一问题的研究相比，评估的种群数量最多可减少96.2%。这种定制的外骨骼使用一个小型线性致动器，在屈曲过程中以近乎恒定的机械优势向指尖提供稳定的12.45 N力。它能够在松弛手指中实现重复性指腹捏取动作，提高康复的一致性并便于居家治疗。
