Joshua A Schultz, Rake Nathanael J
The University of Tulsa, Tulsa, Oklahoma, United States of America.
Bioinspir Biomim. 2021 May 10;16(4). doi: 10.1088/1748-3190/abc6b5.
This paper presents a tendon-driven robotic finger with its inspiration derived from the human extensor mechanism. The analytical model presented relates the contractions of the intrinsic muscles of the human hand to abduction-adduction and coordinated motion of proximal and distal interphalangeal joints. The design presented is simplified from the complex webs of fibers appearing in prior works, but preserves the dual role the interossei have of abducting/adducting the finger and flexing it at the metacarpal-phalangeal joint with the finger outstretched. The anatomical feature in our design is that the proximal interphalangeal joint passes through a set of lateral bands as the finger flexes. We discovered that by including a mechanical stop that causes the lateral bands to 'fold' at large enough flexion aids coordinated movements of the two interphalangeal joints as the finger flexes. Because it involves engineering running and sliding fits, this finger admits a concise kinematic model, which accurately predicts the tendon excursions from a known pose. In this work, however, we evaluate what happens when the model is used to search for a sequence of tendon excursions corresponding to a desired movement. We perform several such sequences of tendon excursions experimentally and present the poses that result using motion capture. We also demonstrate executing several types of grasps on an underactuated robotic hand that incorporates this finger design.
本文介绍了一种受人类伸肌机制启发的肌腱驱动机器人手指。所提出的分析模型将人类手部固有肌肉的收缩与手指的外展-内收以及近端和远端指间关节的协调运动联系起来。所展示的设计是从先前作品中出现的复杂纤维网简化而来的，但保留了骨间肌在手指伸展时使手指外展/内收以及在掌指关节处使其弯曲的双重作用。我们设计中的解剖学特征是，当手指弯曲时，近端指间关节穿过一组侧束。我们发现，通过设置一个机械止动装置，使侧束在足够大的弯曲度时“折叠”，有助于手指弯曲时两个指间关节的协调运动。由于它涉及工程中的运行和滑动配合，这个手指具有一个简洁的运动学模型，该模型能根据已知姿势准确预测肌腱的行程。然而，在这项工作中，我们评估当使用该模型搜索与期望运动相对应的一系列肌腱行程时会发生什么。我们通过实验执行了几个这样的肌腱行程序列，并使用动作捕捉展示了所得到的姿势。我们还展示了在一个采用这种手指设计的欠驱动机器人手上执行几种类型的抓握动作。
