NUSENSE: SHEAR BASED ROBUST OPTICAL TACTILE SENSOR

Abstract

In this study, a new optical tactile sensing method that focuses on detecting shear strain rather than just pressure, which is traditionally used in most tactile sensors is presented. Drawing from principles in continuum mechanics, the importance of shear strain as a key parameter in tactile perception is highlighted. This work approach involves a layer of silicone rubber dyed with colored ink to visualize and measure the magnitude of shear deformation. To validate the concept, the NUSense optical tactile sensor was created, which integrates a wide-angle camera to observe the deformation of the soft layer when subjected to external forces. The deformation—mainly elongation due to the Poisson effect—is captured optically, offering insights into the shear behavior of the material. Since the accuracy of the sensor depends heavily on the long-term stability of the silicone’s mechanical and optical properties, repeated loading tests using a robotic arm to evaluate durability and consistency were performed. How this sensing method could be applied to tasks such as force estimation and determining contact positions was explored, potentially expanding its use in robotic manipulation and soft interaction interfaces.