IEEE Trans Haptics. 2017 Jul-Sep;10(3):418-430. doi: 10.1109/TOH.2017.2672969. Epub 2017 Feb 22.
Virtual reality systems would benefit from a compelling force sensory substitute when workspace or stability limitations prevent the use of kinesthetic force feedback systems. We present a wearable fingertip haptic device with the ability to make and break contact in addition to rendering both shear and normal skin deformation to the fingerpad. A delta mechanism with novel bias spring and tether actuator relocation method enables the use of high-end motors and encoders, allowing precise device control: 10 Hz bandwidth and 0.255 mm RMS tracking error were achieved during testing. In the first of two experiments, participants determined the orientation of a stiff region in a surrounding compliant virtual surface with an average angular error of 7.6 degree, similar to that found in previous studies using traditional force feedback. In the second experiment, we evaluated participants' ability to interpret differences in friction. The Just Noticeable Difference (JND) of surface friction coefficient discrimination using our skin deformation device was 0.20, corresponding with a reference friction coefficient of 0.5. While higher than that found using kinesthetic feedback, this demonstrates that users can perceive differences in surface friction without world-grounded kinesthetic forces. These experiments show that three DoF skin deformation enables both stiffness and friction discrimination capability in the absence of kinesthetic force feedback.
虚拟现实系统在工作空间或稳定性限制阻止使用运动力反馈系统时，将受益于引人入胜的力觉替代。我们提出了一种可穿戴指尖触觉设备，除了向指垫呈现剪切和法向皮肤变形之外，还具有接触和断开接触的能力。带有新型偏置弹簧的Delta 机构和系绳致动器重新定位方法可使用高端电机和编码器，从而实现设备的精确控制：在测试过程中达到了 10 Hz 的带宽和 0.255 mm RMS 跟踪误差。在两个实验中的第一个实验中，参与者使用周围柔顺虚拟表面中的刚性区域确定了刚性区域的方向，平均角度误差为 7.6 度，与使用传统力反馈的先前研究中的结果相似。在第二个实验中，我们评估了参与者解释摩擦差异的能力。使用我们的皮肤变形设备的表面摩擦系数可区分性的Just Noticeable Difference（JND）为 0.20，对应的参考摩擦系数为 0.5。虽然高于使用运动力反馈的结果，但这表明用户可以感知到表面摩擦的差异，而无需基于世界的运动力反馈。这些实验表明，在没有运动力反馈的情况下，三个自由度的皮肤变形可以实现刚度和摩擦的辨别能力。
