Bio-inspired Flexible Sensing Technology for Next-Generation HMI: Ultrasensitive Crack-based Strain Sensors

The current stage of the development of the Human-Machine Interaction (HMI) systems, as rigid motion control systems, is replaced by an anthropomorphic sense of touch, forcing robot manipulators to have skin-like sensory abilities. But nowadays, flexible electronics are facing a fundamental dilemma of sensitivity versus stretchability. The paper will review the process of the ultrasensitive strain sensor design involving a bio-inspired micro-crack structure. It investigates the mechanotransduction of biological systems, first, to derive the theoretical basis of structural gating. Second, the paper investigates the application of modulus mismatch to stress concentration in arthropod-inspired designs. Third, the research explains the Disconnect-Connect model and the effects of quantum tunneling that make gating crack-based sensors so much higher than conventional limits to sensors. Lastly, the paper compares this technology with surface electromyography and finds that it has a better signal-to-noise ratio and latency in closed-loop control. The review states that structural bio-mimicry is an imperative pathway to pursuing the aim of high-fidelity HMI.