When interacting with an object, we use kinesthetic and tactile information to create our perception of the object's properties and to prevent its slippage using grip force control. We previously showed that applying artificial skin-stretch together with, and in the same direction as, kinesthetic force increases the perceived stiffness. Here, we investigated the effect of the direction of the artificial stretch on stiffness perception and grip force control. We presented participants with kinesthetic force together with negative or positive artificial stretch, in the opposite or the same direction of the natural stretch due to the kinesthetic force, respectively. Our results showed that artificial skin-stretch in both directions augmented the perceived stiffness; however, the augmentation caused by the negative stretch was consistently lower than that caused by the positive stretch. Additionally, we proposed a computational model that predicts the perceptual effects based on the preferred directions of the stimulated mechanoreceptors. When examining the grip force, we found that participants applied higher grip forces during the interactions with positive skin-stretch in comparison to the negative skin-stretch, which is consistent with the perceptual results. These results may be useful in tactile technologies for wearable haptic devices, teleoperation, and robot-assisted surgery.

中文翻译：

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人造皮肤拉伸对刚度感知和握力控制的特定方向影响

当与物体交互时，我们使用动觉和触觉信息来创建对物体属性的感知，并使用握力控制来防止其滑动。我们之前表明，将人工皮肤拉伸与动觉力一起并沿相同方向应用会增加感知的硬度。在这里，我们研究了人工拉伸的方向对刚度感知和握力控制的影响。我们向参与者提供动觉力以及负或正的人工拉伸，分别在与动觉力引起的自然拉伸相反或相同的方向上。我们的结果表明，双向的人工皮肤拉伸增强了感知的硬度；然而，负拉伸引起的增强始终低于正拉伸引起的增强。此外，我们提出了一种计算模型，可以根据受刺激的机械感受器的首选方向来预测感知效果。在检查握力时，我们发现与负皮肤拉伸相比，参与者在与正皮肤拉伸的交互过程中施加了更高的握力，这与感知结果一致。这些结果可能对可穿戴触觉设备、远程操作和机器人辅助手术的触觉技术有用。