Toward human-like touch sense via a bioinspired soft finger with self-decoupled bending and force sensing

Highlights•A bioinspired soft finger with proprioception and tactile sensing•A self-decoupled bimodal sensor with high performance and mechanical durability•Human-finger-like softness detection by monitoring the bending and exerted force•Demonstration of the soft finger for lump searching and pulse-taking like a "robodoctor"SummaryThe sense of touch means not only detecting force passively but also effortfully moving our fingers to touch and "feel" the world. Existing soft robotic hands can produce hand-like movements but are still far behind in terms of their sensing capabilities. Here, we propose a bioinspired soft finger (BSF) with self-decoupled bending and force sensing via a seamlessly integrated conductive fiber coil. By measuring the inductance and resistance, bending angle and force at the fingertip can be obtained with high resolutions of 0.02° and 0.4 mN, respectively. Both the sensing and actuation of the BSF have a response time (50 ms) comparable to that of human fingers and are mechanically durable for practical applications. The BSF can achieve a human-like touch sense of object stiffness and identify lumps underneath "normal tissues" by simply pressing it. Moreover, it can automatically locate the artery at a participant's wrist and take the pulse.Graphical abstract