Platkiewicz Jonathan, Lipson Hod, Hayward Vincent
The City College of New York, The City University of New York, Department of Mathematics, New York, NY 10031, USA.
Columbia University, Department of Mechanical Engineering, New York, NY 10027, USA.
Sci Rep. 2016 Mar 24;6:23551. doi: 10.1038/srep23551.
Most tactile sensors are based on the assumption that touch depends on measuring pressure. However, the pressure distribution at the surface of a tactile sensor cannot be acquired directly and must be inferred from the deformation field induced by the touched object in the sensor medium. Currently, there is no consensus as to which components of strain are most informative for tactile sensing. Here, we propose that shape-related tactile information is more suitably recovered from shear strain than normal strain. Based on a contact mechanics analysis, we demonstrate that the elastic behavior of a haptic probe provides a robust edge detection mechanism when shear strain is sensed. We used a jamming-based robot gripper as a tactile sensor to empirically validate that shear strain processing gives accurate edge information that is invariant to changes in pressure, as predicted by the contact mechanics study. This result has implications for the design of effective tactile sensors as well as for the understanding of the early somatosensory processing in mammals.
触觉取决于压力测量。然而，触觉传感器表面的压力分布无法直接获取，必须从被触摸物体在传感器介质中引起的变形场推断出来。目前，关于应变的哪些分量对触觉传感最具信息性尚无共识。在此，我们提出与形状相关的触觉信息从剪切应变中恢复比从法向应变中更合适。基于接触力学分析，我们证明当感测到剪切应变时，触觉探针的弹性行为提供了一种强大的边缘检测机制。我们使用基于堵塞的机器人夹具作为触觉传感器，通过实验验证了如接触力学研究所预测的那样，剪切应变处理能给出对压力变化不变的准确边缘信息。这一结果对有效触觉传感器的设计以及对哺乳动物早期体感处理的理解具有启示意义。
