This paper demonstrates fast, accurate, and stable force control in three axes simultaneously when a flat surface is pressed against the human fingerpad. The primary application of this force control is for the automated calibration of a fingernail imaging system, where video images of the human fingernail are used to predict the normal and shear forces that occur when the fingerpad is pressed against a flat surface. The system consists of a six degree-of-freedom magnetic levitation device (MLD), whose flotor has been modified to apply forces to the human fingerpad, which is resting in a passive restraint. The system is capable of taking simultaneous steps in normal force and two axes of shear forces with a settling time of less than 0.2 seconds, and achieves a steady-state error as small as 0.05 N in all three axes. The system is also capable of tracking error of less than 0.2 N when the shear force vector rotates with a frequency of 1 rad/s. This paper also demonstrates the successful tracking of a desired force trajectory in three dimensions for calibrating a fingernail imaging system.
展开▼
机译:本文展示了当将平坦表面压在人的指板上时,可以同时在三个轴上快速,准确和稳定地控制力。此力控制的主要应用是用于指甲成像系统的自动校准,其中人指甲的视频图像用于预测将指垫按在平坦表面上时发生的法向力和剪切力。该系统由一个六自由度的磁悬浮装置(MLD)组成,该磁悬浮装置经过改装,可以向处于被动约束状态的人指板施加力。该系统能够在法向力和两个剪力轴上同时采取步骤,建立时间少于0.2秒,并且在所有三个轴上的稳态误差均小至0.05N。当剪切力矢量以1 rad / s的频率旋转时,该系统还能够跟踪小于0.2 N的误差。本文还演示了在三个方向上成功跟踪所需力轨迹以校准指甲成像系统的过程。
展开▼