Is Power Grasping Contact Continuous or Discrete?
Is Power Grasping Contact Continuous or Discrete?
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DOI：
10.1123/jab.29.5.554
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发表时间：
2013-10-01
影响因子：
1.4
通讯作者：
Zatsiorsky, Vladimir M.
中科院分区：
文献类型：
--
作者：
Pataky, Todd C.;Slota, Greg P.;Zatsiorsky, Vladimir M.
在抓力过程中，局部力最大值的数量反映了中枢神经系统对特定手部区域的优先使用，或解剖限制，或两者兼而有之。以前，双峰和三峰力的最大已经假设的力量把握圆柱形手柄。在这里，我们测量了局部力最大值的数量，分辨率为4.8度，当在垂直于圆柱体长轴的平面上进行推拉时。12名参与者对8个目标产生了外力。接触次数定义为局部最大值超过背景方差的次数。在所有受试者中，在远端指骨和掌骨头处观察到至少4次和最多5次离散接触。因此，我们拒绝先前的双峰或三峰力控制圆柱形抓力的假设。由于我们目前只观察到4-5次接触，考虑到手在屈曲平面上的运动灵活性，这是相当低的，我们也拒绝连续接触的假设，这是当前抓取分类所固有的。提出了一种改进现有抓取分类的方法，其中功率抓取包含连续接触和离散接触的单独分支，并且仅通过抓取可操作性来区分功率抓取和精度抓取。
During power grasp, the number of local force maxima reflects either the central nervous system's preferential use of particular hand regions, or anatomical constraints, or both. Previously, both bimodal and trimodal force maxima have been hypothesized for power grasp of a cylindrical handle. Here we measure the number of local force maxima, with a resolution of 4.8 degrees, when performing pushing and pulling efforts in the plane perpendicular to the cylinder's long axis. Twelve participants produced external forces to eight targets. The number of contacts was defined as the number of local maxima exceeding background variance. A minimum of four and a maximum of five discrete contacts were observed in all subjects at the distal phalanges and metacarpal heads. We thus reject previous hypotheses of bimodal or trimodal force control for cylindrical power grasping. Since we presently observed only 4-5 contacts, which is rather low considering the hand's kinematic flexibility in the flexion plane, we also reject hypotheses of continuous contact, which are inherent to current grasping taxonomy. A modification to current grasping taxonomy is proposed wherein power grasp contains separate branches for continuous and discrete contacts, and where power and precision grasps are distinguished only by grasp manipulability.