Current Issue : July-September Volume : 2026 Issue Number : 3 Articles : 5 Articles
A sliding mode–based adaptive control law is proposed for a class of diffusion processes featuring a spatially-varying uncertain diffusivity and equipped with several point-wise actuators located at the two boundaries of the spatial domain as well as in its interior. The system is additionally perturbed by matched disturbances which are assumed to be uniformly bounded along with their time derivatives. The corresponding constant bounds are unknown, thus motivating the use of an adaptive control strategy. To achieve global asymptotic stability of the origin in the 𝐿2-sense, a control law consisting of a proportional and discontinuous term is proposed. The gain of the discontinuous term is continuously adjusted according to a gradient-based adaptation algorithm. The stability and convergence analysis is Lyapunov-based and it constructively yields simple tuning conditions for the controller gain parameters. Simulation results are finally discussed to support the theoretical findings....
This article presents a haptic feedback system combining a flexible electromagnetic actuator with off-the-shelf components and virtual/augmented reality (VR/AR) platform to interact with the skin. The system translates targeted VR signals into localized, real-time vibrations on the forearm. Existing actuator technologies struggle to balance flexibility, scalability, and control over displacement and resonance frequency ranges, limiting their suitability for wearable systems. Moreover, research-oriented devices are highly specialized and costly, making them difficult to reproduce at a large scale. To address these challenges, we propose an actuator design framework with a tunable model that enables control over displacement and resonance frequency. Using this model, we develop a scalable actuator (12 × 12 × 3.6mm3) in a 6 × 4 array, leveraging commercial coils, mounted on a wearable sleeve. The device delivers displacements up to 15.8 μm at a resonance frequency of 220 Hz, aligning with the sensitivity of Pacinian corpuscles for high-frequency vibrotactile feedback. To validate its performance, we implement a VR/AR case study using a Meta Quest 2 system to simulate a haptic laser pointer named “Haptix World”. Our key contributions include: (i) tractable actuator design model, (ii) high-displacement flexible electromagnetic actuator, and (iii) complete human–machine interface pipeline that bridges VR interactions with physical haptics....
We present a modular design strategy for the one-step fabrication of arrays of magnetically responsive microactuators connected to the substrate via compliant hinges. We use direct laser writing in the form of two-photon crosslinking within bilayer films to generate three-dimensional microstructures in which magnetic nanoparticles are embedded in the upper layer. This part of the generated structure drives the actuation, while the hydrogel bottom layer is used to form a mechanically compliant hinge structure. The chemical composition and geometrical features of the hinge control the actuation amplitude, the mechanical properties, and the environmental adaptability. Hydrogel hinges provide stability and strong actuation in an aqueous environment, while stimulusresponsive hinges allow for the dynamic reconfiguration of the actuation and bistable behavior without altering the magnetically driving component. This hinge-based approach establishes a new class of adaptive microactuators and provides a generalizable platform for programmable soft micromachines....
The development of autonomous mobile robots or automated guided vehicles is consistently challenged by energy-storage constraints, and while batteries are the standard solution for mobile robots, dynamic wireless power transfer is an alternative way to supply power without reliance on chemical energy storage. For efficient dynamic wireless power transfer, transmitting coils should be energized as required, necessitating real-time position tracking of the receiving coil. Current prevalent techniques require complex modifications to existing systems and additional position sensors, which increase total costs. This article proposes a novel receiving coil position detection method for wireless power transfer systems without using external receiving coil position detection sensors and describes the application of the sensorless coil position detection method and its advantages compared to other methods. The proposed method was implemented on an existing low-power, miniaturized test bench. The described method was successfully validated and correctly switched transmitting coils, ensuring continuous movement of an electric vehicle, therefore proving its viability as a potential new approach for sensorless receiving-coil detection. Experimental results demonstrate that the prototype achieved a maximum power transfer efficiency of 53.8% while maintaining continuous transmitting coil switching operation at vehicle speeds up to 77 cm/s....
Flexible magnetic sensors have become a hot research topic due to their non-contact human–machine interaction capabilities in areas such as motion recognition and posture detection of intelligent robots, virtual reality (VR) space reconstruction, and the Internet of Things. This study proposes a flexible, low-power three-dimensional (3D) magnetoimpedance (MI) sensor based on a planar FeSiB/PI/graphene microcoil/PI/FeSiB heterostructure. Through the magneto-impedance effect of soft magnetic materials and the magnetoresistance effect of graphene under the synergistic modulation of weak current excitation, this sensor can decouple the magnetic field components in the X, Y, and Z directions with a single measurement, thus guaranteeing the real-time detection capability of a 3D magnetic field. Experimental results show that the proposed 3D magnetic sensor possesses the obvious advantages, such as the low power consumption of 76 μW, high resolutions of 31, 36, and 6992 nT/Hz1/2 in the X, Y, and Z directions, respectively. Additionally, the magnetic sensor exhibits excellent anti-bending performance and can adapt to complex mechanical deformation environments. These characteristics endow it with great application potential in the field of intelligent wearable devices and provide new ideas for the future flexible electronics technology....
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