Tactile sensors capable of quantifying mechanical stimuli through physical contact play a pivotal role in healthcare, prosthetics and humanoid robotics. To enable conformal contact with objects of different surface morphologies, tactile sensors with high mechanical flexibility have been extensively explored. Despite recent advances, most of the currently available flexible tactile sensors are based on electrical properties of functional materials, which often suffer from intrinsic limitations such as hysteresis, parasitic effects, signal crosstalk, and electromagnetic interference. In this work, we present a flexible optical tactile sensor by harnessing the unique optical properties of a soft and plasmonic optical fiber, which is made from composites of gold nanoparticles (GNPs) and elastomers. The tactile sensor is constructed by assembling the nanocomposite fiber in a sandwich structure, where sensitive and instantaneous sensing of contact force with high precision, low hysteresis, and tunable sensitivity is achieved by transducing mechanical stimuli into interpretable light signals. As demonstrations of its potential, the tactile sensor is utilized for real-time monitoring of blood pressure, respiration, as well as providing tactile mapping of hand motions such as tapping, shaking, and grasping. To further verify the feasibility of mimicking tactile perception of human skin, the proposed sensors integrated onto a robot hand are also demonstrated to perceive material hardness, surface roughness and shape of objects
Audience Take Away Notes :
- The optical tactile sensor was made in an all-elastomer sandwich structure assembled with a partially gold nanoparticle-doped PDMS optical fiber. Benefiting from the all-elastomer design, the proposed sensor was intrinsically flexible and stretchable that enabled conformal contact and tactile measurement on complex curved surfaces.
- Taking advantages of the intense localized surface plasmon resonance (LSPR) effect and low elastic modulus of the plasmonic fiber, the tactile sensors can detect contact force over a wide working range with tuned sensitivity.
- We demonstrated the broad applications of the proposed tactile sensor in real-time monitoring of subtle arterial blood pressure, respiration, as well as providing tactile mapping of hand gestures with simultaneous haptic force feedback