A methodology was established to investigate the contact mechanics of the thumb and the index finger at the digit–object interface during precision pinch. Two force/torque transducers were incorporated into an apparatus designed to overcome the thickness of each transducer and provide a flexible pinch span for digit placement and force application. To demonstrate the utility of the device, five subjects completed a pinch task with the pulps of their thumb and index finger. Inter-digit force vector coordination was quantified by examining the (1) force vector component magnitudes, (2) resultant force vector magnitudes, (3) coordination angle: the angle formed by the resultant vectors of each digit, (4) direction angle: the angle formed by each vector and the coordinate axes, and (5) center of pressure locations. It was shown that the resultant force magnitude of the index finger exceeded that of the thumb by 0.8 ± 0.3 N and that the coordination angle between the digit resultant force vectors was 160.2 ± 4.6°. The experimental apparatus and analysis methods provide a valuable tool for the quantitative examination of biomechanics and motor control during dexterous manipulation.

中文翻译：

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量化精确捏合过程中的数字力矢量坐标

建立了一种方法来研究精确捏合过程中拇指和食指在数字-对象界面处的接触力学。两个力/扭矩传感器被整合到一个装置中，该装置旨在克服每个传感器的厚度，并为手指放置和施力提供灵活的捏跨度。为了演示该设备的实用性，五名受试者用拇指和食指的指腹完成了捏捏任务。通过检查（1）力矢量分量大小，（2）合力矢量大小，（3）协调角：由每个数字的合成矢量形成的角度，（4）方向角：每个向量和坐标轴形成的角度，以及 (5) 压力中心位置。结果表明，食指的合力大小超过拇指的 0.8 ± 0.3 N，数字合力矢量之间的协调角为 160.2 ± 4.6°。实验装置和分析方法为灵巧操作过程中生物力学和运动控制的定量检查提供了有价值的工具。