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This work reports a low-cost and easy manufactured optical fiber bubble Fabry–Perot (FP) interferometer (FPI) sensor with optimized manufacturing parameters. The microbubble sensor is fabricated by welding a multimode fiber (MMF) to a single-mode fiber (SMF), followed by hydrofluoric acid (HF) corroded and discharge treatment at the end of the MMF. The manufacturing process is explored and optimized. The optical power of the interference light was increased and forming stability of the bubbles was improved by controlling the corrosion time, type of arc discharge, discharge intensity, discharge time, and number of discharges. To study the relationship between the optical power and the subjected pressure and temperature, a theoretical model of sensing principle is established, and finite element simulation is carried out to analyze the deformation of bubbles under the influence of the external environment. Experimental results show that the sensor has a pressure sensitivity of $- 1\times 10^{-{1}}$ dBm/MPa and a temperature sensitivity of $1.52\,\,{\times }\,\,10^{-{2}}$ dBm/°C. The study gives the influence of multiple preparation parameters on the quality of the sensor, which has good scientific value. The sensor has good prospects in pressure measurement.

The deformation characteristics of the flapping wings are crucial to the enhancement of flight robot performance. In measuring wing deformation with conventional stereo vision and structured light projection, issues such as occlusion and limited field of view exist. In this article, we propose an innovative “Kite-Lead” approach for measuring the dynamic deformation of flapping-wing robots based on fiber Bragg grating (FBG), which can realize outdoor flight monitoring under unconstrained conditions. Under the theoretical guidance of the surface reconstruction algorithm and the fluid-structure interaction (FSI) analysis, we develop a sensing strategy for wing deformation employing flexible sensor arrays with 28 FBGs. FBGs are directly encapsulated using silicone adhesive at specific locations on the wing surface. Outdoor continuous flight tests are conducted to investigate the strain distributions of all 28 sensing points during the release phase within 1 s and stabilization phase within 0.4 s. Through the wavelength outputs, the wings’ curvature and bending direction can be inverted, and then the wings’ 3-D shape is reconstructed to reveal the deformation characteristics of the flapping-wing robot. This article presents a system for measuring the dynamic deformation of flapping-wing robots without obstructing the line of sight or limiting the available flight space. The research results resolve the existing measurement issues and provide valuable test technology and scientific information for the flapping-wing flying robot.

As an important component of automated guided vehicle (AGV) active safety systems, the active rollover prevention (ARP) control has been widely studied. In this paper, a fixed-time adaptive sliding mode (FTASM) control strategy based on nested adaptive law (NAL) and improved super-twisting observer (ISTO) is developed for the AGV. Firstly, the lateral and roll motion dynamics of AGV are established, and the ARP problem is transformed into the yaw stability control with constraints. Subsequently, a faster fixed-time stable system-based FTASM composite controller is proposed to guarantee a fixed and faster convergence time of the yaw rate tracking error, such that the rollover stability will reach a region of permissible risk. The adoption of NAL enables the adaptive controller to automatically search the minimum switching gain satisfying the reaching condition of sliding mode, thus the conservative assumption constraint of the disturbance upper bound is released. In addition, an ISTO is developed to estimate the unknown disturbance to further improve the control robustness and attenuate the control chattering. The closed-loop stability analysis is rigorously given by Lyapunov theory. Finally, the performance of the proposed control strategy is validated by hardware-in-loop simulations with Adams and Matlab software and an actual steer-by-wire plant.

To assure safety and comfort for autonomous vehicles (AVs) in the mixed traffic environment, a longitudinal potential field-based car-following model considering the cut-in behavior from an adjacent vehicle is established in this study. The longitudinal potential field (LPF), which includes the cut-in potential field, the hazard potential field and the velocity potential field, is constructed to quantitatively characterize the influence of the surrounding environment on the AVs. The cut-in potential field is created to indicate the possibility of cut-in behavior from the adjacent vehicle, the hazard potential field is intended to depict the risk of colliding with the preceding vehicle, and the velocity potential field is created to show how velocity impacts the following behavior. The proposed model is obtained by calculating the field force in the LPF, and its parameters are calibrated using the genetic algorithm. Comparative simulations are executed to verify the remarkable performance of the proposed model, in terms of acceleration, velocity, and headway tracking as well as responding to the cut-in behavior under three different driving conditions.

Nanoscale microemulsions have been utilized as delivery carriers for nutraceuticals and active biological drugs. Herein, we designed and synthesized a novel oil in water (O/W) fluorescent microemulsion based on isoamyl acetate, polyoxyethylene castor oil EL (CrEL), and water. The microemulsion emitted bright blue fluorescence, thus exhibiting its potential for active drug detection with label-free strategy. The microemulsion exhibited excitation-dependent emission and distinct red shift with longer excitation wavelengths. Lifetime and quantum yield of fluorescent microemulsion were 2.831 ns and 5.0%, respectively. An excellent fluorescent stability of the microemulsion was confirmed by altering pH, ionic strength, temperature, and time. Moreover, we proposed a probable mechanism of fluorochromic phenomenon, in connection with the aromatic ring structure of polyoxyethylene ether substituent in CrEL. Based on our findings, we concluded that this new fluorescent microemulsion is a promising drug carrier that can facilitate active drug detection with a label-free strategy. Although further research is required to understand the exact mechanism behind its fluorescence property, this work provided valuable guidance to develop new biosensors based on fluorescent microemulsion.