A research team led by Prof. DONG Erbao from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS), collaborating with Prof. YU Xinge from the City University of Hong Kong, developed a novel tactile perception method based on the structural color of flexible grating structural color. The study was published in National Science Review.

Vision-based tactile sensors (VTSs) play a crucial role in facilitating robots to perform complex and precise operations. However, existing VTS primarily rely on geometric optics or marker tracking technology, which severely limits their resolution and accuracy in force-position recognition.

In this study, inspired by the structural color of Morpho butterfly wings, researchers utilized the structural color patterns formed by the flexible grating films under LED white light illumination to represent tactile information. To better estimate the single-point contacts from structural color images, they employed deep learning algorithms to enhance information decoding and optimize dataset configurations.

This novel VTS design, called IrisTact, achieved high spatial resolution and force accuracy at contact points, significantly improving the overall performance of tactile recognition. IrisTact fully exploits the rich tactile information contained in the structural color patterns, surpassing current VTSs in terms of spatial resolution for contact point localization and accuracy of force recognition.

The new method demonstrated broad applicability. Based on the modular design of core components, researchers developed sensor prototypes for three typical application scenarios: low-frequency vibration detection, whisker sensing, and three-dimensional (3D) contact perception. 

With an additional end-effector transmitting vibration to the film, the vibration sensor can measure subtle low-frequency vibration signals based on the elasticity of the film. The bionic whisker sensor, featuring a rigid-flexible coupling whisker, can detect pulse frequency and airflow disturbances. The flexible grating film can be independently used in endoscopic systems to enable circular 3D contact perception.

IrisTact provides a new way for intelligent sensing, and exhibits application potential in robotic perception, environment monitoring and medical devices.