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

这项研究考察了在使用精确握力的握持和举起任务中，扭矩在手指握持的物体界面上的作用效果。力-扭矩传感器和Fast Trak角度/位置传感器被安装在握持装置中。在第一个实验中，受试者(n=6)握住仪器一段时间，通过减少握力来旋转指尖。握力与扭矩呈线性关系。对于不同的抓地面，旋转滑块的摩擦系数约为直线滑块摩擦系数的7倍。在第二个实验中，在握住仪器的过程中，注射利多卡因来阻断指尖。取消了对扭矩的握力调整。结果表明，握力对扭矩的调节是通过指尖的皮肤传入进行的。当在指尖麻醉下给出物体在旋转任务中的运动学(角度)变化的视觉信息时，握力调节得到改善。在第三个实验中，受试者(n=11)从桌子上取下仪器。握持装置有一个附加的和可移动的重量附着在装置内，通过它产生不同的扭矩条件。握力的变化率被适当地调整为扭矩。在没有通知受试者的情况下改变扭矩时，初始握力的时间进程与之前的举重试验相同。结果表明，扭矩可以作为前馈控制握力的参数。在第四个实验中，通过让受试者看到握力装置上的附加重量，给出了关于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举起物体的抓地力的前馈控制。

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.