Fig. 3: Mechanical sensors.
From: Advances and perspectives in fiber-based electronic devices for next-generation soft systems
a Schematic illustration of a fiber-based pressure sensor and a cross-sectional SEM image of the conductive fibers. The sensing mechanism is based on measuring the change in capacitance formed at the intersection of two stacked conductive fibers. Reprinted with permission122. Copyright 2015, WILEY-VCH Verlag GmbH & Co. KgaA, Weinheim. b Schematic diagram of a resistive-capacitive hybrid fiber pressure sensor and corresponding cross-sectional SEM image showing the distinct layers of the fiber electrode. Reprinted with permission123. Copyright 2023, American Chemical Society. c Schematic of scalable braiding technology and SEM images of the top and cross-sectional morphology of the smart yarn. (UBSY Ultrahigh-strength ultra-high-molecular-weight polyethylene Braided Smart Yarn, UHMWPE Ultra-high-molecular-weight Polyethylene, PA Polyamide) d Photographs of the weft-knitted wearable sensor (WTS). e Voltage output of the smart elbow guard corresponding to various arm bending angles. c–e Reprinted with permission124. Copyright 2024, Springer Nature. f Gesture-based information transmission using a core–shell nanostructured smart fiber. Reprinted with permission125. Copyright 2024, WILEY-VCH Verlag GmbH & Co. KgaA, Weinheim. g Wirelessly received sensing signals from the ionic hydrogel fiber strain sensor corresponding to different motion states of a robotic bird. Various motions include static wings at different positions, and high-speed wings flapping at different frequencies. Reprinted with permission126. Copyright 2022, Springer Nature. h Images showing the posture and movement of the user, along with a tactile frame capable of monitoring them. Reprinted with permission118. Copyright 2021, Springer Nature. i Controlling a robotic hand using a smart glove underwater. j t-distributed stochastic neighbor embedding (t-SNE) visualization of 3,000 strain data points (150 samples for each of the 20 gestures). Each point in the figure represents the strain information of one hand gesture projected from 5 dimensions into 2 dimensions. i, j Reprinted with permission130. Copyright 2022, Elsevier Inc. k Photograph of the artificial muscles. l Schematic illustration of the artificial muscle architecture (i, ii, and iii correspond to the liquid metal-based sensing and electrothermal core, the cured liquid crystal elastomer actuation layer, and the adhesive outer sheath). m Schematic of illustration of artificial muscle feedback sensing and actuation by external pressure. k–m Reprinted with permission131. Copyright 2025, Elsevier Inc.
