Niu Xun, Latash Mark L, Zatsiorsky Vladimir M
Department of Kinesiology, The Pennsylvania State University, University Park, USA.
J Mot Behav. 2012;44(2):69-85. doi: 10.1080/00222895.2011.650735. Epub 2012 Feb 24.
The study examines whether the cost functions reconstructed from experimental recordings are reproducible over time. Participants repeated the trials on three days. By following Analytical Inverse Optimization procedures, the cost functions of finger forces were reconstructed for each day. The cost functions were found to be reproducible over time: application of a cost function C(i) to the data of Day j (i≠j) resulted in smaller deviations from the experimental observations than using other commonly used cost functions. Other findings are: (a) the 2nd order coefficients of the cost function showed negative linear relations with finger force magnitudes; (b) the finger forces were distributed on a 2-dimensional plane in the 4-dimensional finger force space for all subjects and all testing sessions; (c) the data agreed well with the principle of superposition, i.e. the action of object prehension can be decoupled into the control of rotational equilibrium and slipping prevention.
该研究考察了从实验记录中重建的成本函数是否随时间可重现。参与者在三天内重复了这些试验。通过遵循分析逆优化程序，每天都重建了手指力的成本函数。结果发现成本函数随时间是可重现的：将成本函数C(i)应用于第j天的数据（i≠j），与使用其他常用成本函数相比，与实验观测值的偏差更小。其他发现如下：（a）成本函数的二阶系数与手指力大小呈负线性关系；（b）在所有受试者和所有测试环节中，手指力在四维手指力空间的二维平面上分布；（c）数据与叠加原理吻合良好，即物体抓握动作可解耦为旋转平衡控制和防滑控制。
