Abstract
This study presents an intelligent soft robotic system capable of perceiving, describing, and sorting objects based on their physical properties. This work introduces a bimodal self‐powered ...flexible sensor (BSFS) based on the triboelectric nanogenerator and giant magnetoelastic effect. The BSFS features a simplified structure comprising a magnetoelastic conductive film and a packaged liquid metal coil. The BSFS can precisely detect and distinguish touchless and tactile models, with a response time of 10 ms. By seamlessly integrating the BSFSs into the soft fingers, this study realizes an anthropomorphic soft robotic hand with remarkable multimodal perception capabilities. The touchless signals provide valuable insights into object shape and material composition, while the tactile signals offer precise information regarding surface roughness. Utilizing a convolutional neural network (CNN), this study integrates all sensing information, resulting in an intelligent soft robotic system that accurately describes objects based on their physical properties, including materials, surface roughness, and shapes, with an accuracy rate of up to 97%. This study may lay a robotic foundation for the hardware of the general artificial intelligence with capacities to interpret and interact with the physical world, which also serves as an interface between artificial intelligence and soft robots.
Interfacing with the human body, wearable and implantable bioelectronics are a compelling platform technology for healthcare monitoring and medical therapeutics. However, clinical adoption of these ...devices is largely shadowed by their weakness in humidity resistance, stretchability, durability, and biocompatibility. In this work, we report a self-powered waterproof biomechanical sensor with stretchability up to 440% using the giant magnetoelastic effect in a soft polymer system. By manipulating the magnetic dipole alignment, the sensor achieved a particularly broad sensing range from 3.5 Pa to 2000 kPa, with a response time of ∼3 ms. To validate the excellent performance of the magnetoelastic sensor in biomonitoring, both ex vivo porcine heart testing and in vivo rat model testing were performed for cardiovascular monitoring and heart disease diagnosis. With the obtained sensing data, we have successfully detected ventricular arrhythmia and ventricular fibrillation in the Sprague–Dawley rat model. Holding a collection of compelling features, including minimal hysteresis, ultrawide sensing range, waterproofness, and biocompatibility, the magnetoelastic sensor represents a unique platform technology for self-powered biomonitoring in both wearable and implantable manners.
The magnetoelastic effect-the variation of the magnetic properties of a material under mechanical stress-is usually observed in rigid alloys, whose mechanical modulus is significantly different from ...that of human tissues, thus limiting their use in bioelectronics applications. Here, we observed a giant magnetoelastic effect in a soft system based on micromagnets dispersed in a silicone matrix, reaching a magnetomechanical coupling factor indicating up to four times more enhancement than in rigid counterparts. The results are interpreted using a wavy chain model, showing how mechanical stress changes the micromagnets' spacing and dipole alignment, thus altering the magnetic field generated by the composite. Combined with liquid-metal coils patterned on polydimethylsiloxane working as a magnetic induction layer, the soft magnetoelastic composite is used for stretchable and water-resistant magnetoelastic generators adhering conformably to human skin. Such devices can be used as wearable or implantable power generators and biomedical sensors, opening alternative avenues for human-body-centred applications.
Strain and temperature are important physiological parameters for health monitoring, providing access to the respiration state, movement of joints, and inflammation processes. The challenge for smart ...wearables is to unambiguously discriminate strain and temperature using a single sensor element assuring a high degree of sensor integration. Here, a dual‐mode sensor with two electrodes and tubular mechanically heterogeneous structure enabling simultaneous sensing of strain and temperature without cross‐talk is reported. The sensor structure consists of a thermocouple coiled around an elastic strain‐to‐magnetic induction conversion unit, revealing a giant magnetoelastic effect, and accommodating a magnetic amorphous wire. The thermocouple provides access to temperature and its coil structure allows to measure impedance changes caused by the applied strain. The dual‐mode sensor also exhibits interference‐free temperature sensing performance with high coefficient of 54.49 µV °C−1, low strain and temperature detection limits of 0.05% and 0.1 °C, respectively. The use of these sensors in smart textiles to monitor continuously breathing, body movement, body temperature, and ambient temperature is demonstrated. The developed multifunctional wearable sensor is needed for applications in early disease prevention, health monitoring, and interactive electronics as well as for smart prosthetics and intelligent soft robotics.
A dual‐mode elastic sensor consisting of a tubular mechanically heterogeneous structure and featuring a hybrid detection mechanism enables real‐time measurement of strain and temperature stimuli without interference. The sensor exhibits high detection accuracy of 0.05% strain and 0.1 °C. To highlight application potential, the sensor is integrated in textile to detect breathing/human‐movement and body temperature continuously and independently, as well as ambient temperature.
Magnetoelastic effect characterizes the change of materials' magnetic properties under mechanical deformation, which is conventionally observed in some rigid metals or metal alloys. Here we show ...magnetoelastic effect can also exist in 1D soft fibers with stronger magnetomechanical coupling than that in traditional rigid counterparts. This effect is explained by a wavy chain model based on the magnetic dipole-dipole interaction and demagnetizing factor. To facilitate practical applications, we further invented a textile magnetoelastic generator (MEG), weaving the 1D soft fibers with conductive yarns to couple the observed magnetoelastic effect with magnetic induction, which paves a new way for biomechanical-to-electrical energy conversion with short-circuit current density of 0.63 mA cm
, internal impedance of 180 Ω, and intrinsic waterproofness. Textile MEG was demonstrated to convert the arterial pulse into electrical signals with a low detection limit of 0.05 kPa, even with heavy perspiration or in underwater situations without encapsulations.
Symmetric anisotropic interaction can be ferromagnetic and antiferromagnetic at the same time but for different crystallographic axes. We show that the competition of anisotropic interactions of ...orthogonal irreducible representations can be a general route to obtain new exotic magnetic states. We demonstrate it here by observing the emergence of a continuously tunable 12-layer spatial spin modulation when distorting the square-lattice planes in the quasi-two-dimensional antiferromagnetic Sr2IrO4 under in situ shear strain. This translation-symmetry-breaking phase is a result of an unusual strain-activated anisotropic interaction which is at the fourth order and competing with the inherent quadratic anisotropic interaction. Such a mechanism of competing anisotropy is distinct from that among the ferromagnetic, antiferromagnetic, and/or the Dzyaloshinskii-Moriya interactions, and it could be widely applicable and highly controllable in low-dimensional magnets.
This Letter demonstrates spin wave resonance (SWR) owing to the gyromagnetic effect by propagating a Rayleigh-type surface acoustic wave (R-SAW) through ferromagnetic thin films. The SWR amplitude in ...a NiFe film shows a higher-order frequency variation than in a magnetoelastic Ni film. This frequency dependence is well understood in terms of the presence of a gyromagnetic field attributable to the local lattice rotation in the R-SAW. From the frequency dependence of the SWR amplitude, the gyromagnetic SWR could be separated from another SWR caused by a magnetoelastic effect of the ferromagnet.
In this study, we present the observation of the giant magnetoelastic effect that occurs in soft elastomer systems without the need of external magnetic fields and possesses a magnetomechanical ...coupling factor that is four times larger than that of traditional rigid metal-based ferromagnetic materials. To investigate the fundamental scientific principles at play, we built a linear model by using COMSOL Multiphysics, which was consistent with the experimental observations. Next, by combining the giant magnetoelastic effect with electromagnetic induction, we developed a magnetoelastic generator (MEG) for biomechanical energy conversion. The wearable MEG demonstrates an ultrahigh output current of 97.17 mA, a low internal impedance of around ∼40 Ω, and an intrinsic waterproof property. We further leveraged the wearable MEG as an ultrahigh current power source to drive a Joule-heating textile for personalized thermoregulation, which increased the temperature of the fiber-shaped resistor by 0.2 °C. The development of the wearable MEG will act as an alternative and compelling approach for on-body electricity generation and arouse a wide range of possibilities in the renewable energy community.
The current energy crises and imminent danger of global warming severely limit the ability to scale societal development sustainably. As such, there is a pressing need for utilizing renewable, green ...energy sources, such as wind energy, which is ubiquitously available on Earth. In this work, a fundamentally new wind‐energy‐harvesting technology is reported, which is based on the giant magnetoelastic effect in a soft composite system, namely, magnetoelastic generators. Its working principle is based on wind‐induced mechanical deformation, which alters the magnetic field in a soft system converting the wind energy into electricity via electromagnetic induction from arbitrary directions. The wind‐energy‐harvesting system features a low internal impedance of 68 Ω, a high current density of 1.17 mA cm–2, and a power density of 0.82 mW cm–2 under ambient natural wind. The system is capable of sustainably driving small electronics and electrolytically splitting water. The system can generate hydrogen at a rate of 7.5 × 10–2 mL h–1 with a wind speed of 20 m s−1. Additionally, since magnetic fields can penetrate water molecules, the magnetoelastic generators are intrinsically waterproof and work stably in harsh environments. This work paves a new way for wind‐energy harvesting with compelling features, which can contribute largely to the hydrogen economy and the sustainability of human civilization.
A fundamentally new wind‐energy‐harvesting technology based on the giant magnetoelastic effect in a soft composite system is reported. Wind‐induced mechanical deformation alters the magnetic field in the soft system, which is able to convert the wind energy into electricity via electromagnetic induction from arbitrary directions. It features a high current density of 1.17 mA cm–2 and intrinsic waterproofness.
We propose the idea of a spin-lattice liquid, in which spin and lattice degrees of freedom are strongly coupled and remain disordered and fluctuating down to low temperatures. We show that such a ...state arises naturally from a microscopic analysis of a class of molybdate pyrochlore compounds, and is driven by a giant magnetoelastic effect. Finally, we argue that this could explain some of the experimental features of Y_{2}Mo_{2}O_{7}.
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