Adaptive control finger force to tangential torque at the finger-object interface during holding and lifting tasks with a precision grip.

本研究考察了扭矩切向作用于手指抓住的对象界面期间，使用精密握持和提升任务。力-扭矩传感器和快速跟踪角度/位置传感器安装在抓地力装置中。在第一个实验中，受试者（n = 6）持有仪器一段时间，并在指尖通过减小握力旋转仪器。握持力与扭矩呈线性相关。对于不同的握持面，旋转卡瓦的估计摩擦系数大约是线性卡瓦的7倍。在第二组实验中，手握器械时，用利多卡因阻断指尖。取消了抓地力对扭矩的调整。结果表明，握力对扭矩的调节是通过指尖的皮肤传入神经来实现的。在指尖麻醉下，给出旋转任务中物体运动（角度）变化的视觉信息，改进了握持力的调节。在第三个实验中，受试者（n = 11）将仪器从桌子上抬起来。抓地力装置有一个附加的和可移动的砝码附加在装置内部，通过该砝码创建不同的扭矩条件。抓地力的变化率适当地与扭矩成比例。在不通知被试的情况下改变扭矩时，初始握力的时间过程与前一次试验相同。实验结果表明，握力的前馈控制以扭矩为参数。在第四个实验中，通过让被试看到附着在握力装置上的额外重量，给出了有关重量分布的视觉信息的效果。研究发现，这种视觉信息实际上可以帮助调整对举起物体的握力的前馈控制。

This study examined the effects of torque tangentially acting at the finger-grasped object interface during holding and lifting tasks using a precision grip. A force-torque sensor and a Fast Trak angle/position sensor were installed in a grip apparatus. In the first experiment, the subjects(n = 6)held the apparatus for some period of time and rotated it at the fingertip by decreasing the grip force. The holding grip force was linearly related to torque. The estimated coefficient of friction for rotational slips was about 7 times larger than that for linear slips for varied grip surfaces. In the second experiment, the fingertip was blocked by the injection of Lidocaine during holding the apparatus. The grip force adjustment to torque was abolished. The findings indicated that the grip force adjustment to torque was made by cutaneous afferents at the fingertip. When visual information concerning the kinematic(angle)changes of the object during the rotation task was given under the fingertip anaestheria, the grip force adjustment was improved. In the third experiment, the subjects(n = 11)lilfted the apparatus from a table. The grip apparatus had an additional and movable weight attached inside the apparatus by which varied torque conditions were created. The rate change of grip force was appropriately scaled to torque. When torque was changed without informing the subjects, the time course of initial grip force followed that of the previous lifting trial. The findings suggested that torque was used as a parameter for feedforward control of the grip force, In the fourth experiment, the effect of visual information concerning the weight distribution was given by allowing the subjects to see the additional weight attached to the grip apparatus. It was found that such visual information can actually help in adjustment of feedforward control of the grip force for lifting of objects.