This paper investigates the path-guided distributed formation control of networked autonomous surface vehicles(ASVs) subject to model uncertainties and environmental disturbances. A safety-certified path-guided coordi...
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This paper investigates the path-guided distributed formation control of networked autonomous surface vehicles(ASVs) subject to model uncertainties and environmental disturbances. A safety-certified path-guided coordinated control method is proposed for multiple ASVs to achieve a distributed formation in obstacle environments. Specifically, a neural predictor with a high-order tuner is presented to approximate unknown nonlinearities with accelerated learning performance. Subsequently, control Lyapunov functions(CLFs) and control barrier functions(CBFs) are constructed for mapping stability constraints and safety constraints on states to control inputs. A quadratic optimization problem is constructed with the norm of control inputs as the objective function, CLFs and CBFs as constraints. Neurodynamic optimization is used to deal with the quadratic programming problem and generate the optimal kinetic control signals, thereby attaining the desired safe formation. Unlike the high-order CBF, a CBF backstepping method is proposed to establish safety constraints such that repeated time derivatives of system nonlinearities can be avoided. The multi-ASVs system is ensured to be input-to-state safe irrespective of high-order relative degree. Through the Lyapunov theory, the multi-ASVs system is proven to be input-to-state stable. Finally, simulation results are presented to validate the efficacy of the presented safety-certified distributed formation control for networked ASVs.
To safeguard the ocean ecosystem,fuel cells are excellent candidates as the primary energy supply for marine vessels due to their high efficiency,low noise,and ***,fuel cells in hybrid power systems are highly suscept...
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To safeguard the ocean ecosystem,fuel cells are excellent candidates as the primary energy supply for marine vessels due to their high efficiency,low noise,and ***,fuel cells in hybrid power systems are highly susceptible to load transients,which can severely damage fuel cells and shorten their ***,the formulation of energy management strategies accounting for power degradation is crucial and *** this study,an improved strategy for equivalent consumption minimization strategy(ECMS)considering power degradation is *** improved energy control strategy effectively controls the energy distribution of hydrogen fuel cells,lithium batteries,and supercapacitors in hybrid power *** proposed control strategy combines the ECMS with an adaptive *** main objective of the ECMS is to allocate power to the fuel cell systems and energy storage systems(ESS)to stabilize the power output of fuel cells,prolong their service life,and reduce the hydrogen consumption in fuel *** adaptive filteringmethod,by low-pass filtering of the energy in the energy storage system,is used to allocate power between lithium batteries and supercapacitors to minimize the effect of transient and peak energy output on the lifespan of lithium *** verify the superiority of the control strategy,a mathematical model for the hybrid power system is *** comparison to traditional ECMS and traditional ECMS considering degradation,the improved ECMS considering power degradation shows better performance in the overall economy,the durability of fuel cells and batteries,and system dynamic performance.
In recent decades, control performance monitoring(CPM) has experienced remarkable progress in research and industrial applications. While CPM research has been investigated using various benchmarks, the historical dat...
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In recent decades, control performance monitoring(CPM) has experienced remarkable progress in research and industrial applications. While CPM research has been investigated using various benchmarks, the historical data benchmark(HIS) has garnered the most attention due to its practicality and effectiveness. However, existing CPM reviews usually focus on the theoretical benchmark, and there is a lack of an in-depth review that thoroughly explores HIS-based methods. In this article, a comprehensive overview of HIS-based CPM is provided. First, we provide a novel static-dynamic perspective on data-level manifestations of control performance underlying typical controller capacities including regulation and servo: static and dynamic properties. The static property portrays time-independent variability in system output, and the dynamic property describes temporal behavior driven by closed-loop feedback. Accordingly,existing HIS-based CPM approaches and their intrinsic motivations are classified and analyzed from these two ***, two mainstream solutions for CPM methods are summarized, including static analysis and dynamic analysis,which match data-driven techniques with actual controlling behavior. Furthermore, this paper also points out various opportunities and challenges faced in CPM for modern industry and provides promising directions in the context of artificial intelligence for inspiring future research.
Dear Editor,This letter addresses long duration coverage problem of multiple robotic surface vehicles(RSVs) subject to battery energy constraints,in addition to uncertainties and disturbances. An anti-disturbance ener...
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Dear Editor,This letter addresses long duration coverage problem of multiple robotic surface vehicles(RSVs) subject to battery energy constraints,in addition to uncertainties and disturbances. An anti-disturbance energy-aware control method is proposed for performing coverage task of RSVs. Firstly, a centroidal Voronoi tessellation(CVT) is used to optimize the partition of the given coverage area.
Magnetic absorbers with high permeability have significant advantages in lowfrequency and broadband electromagnetic wave (EMW) ***,the insufficient magnetic loss and inherent high conductivity of existing magnetic a...
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Magnetic absorbers with high permeability have significant advantages in lowfrequency and broadband electromagnetic wave (EMW) ***,the insufficient magnetic loss and inherent high conductivity of existing magnetic absorbers limit the further expansion of EMW absorption ***,the spinel (FeCoNiCrCu)3O4high-entropy oxides (HEO) are successfully constructed on the surface of FeCoNiCr0.4Cu0.2high-entropy alloys (HEA) through low-temperature oxygen bath *** the one hand,HEO and HEA have different magnetocrystalline anisotropies,which is conducive to achieving continuous natural resonance to improve magnetic *** the other hand,HEO with low conductivity can serve as an impedance matching layer,achieving magneto-electric *** the thickness is 5 mm,the minimum reflection loss (RL) value and absorption bandwidth (RL<-5 d B) of bi-phase high-entropy composites (BPHEC) can reach-12.8 d B and 633 MHz,*** RCS reduction value of multilayer sample with impedance gradient characteristic can reach 18.34 d B *** addition,the BPHEC also exhibits temperaturestable EMW absorption performance,high Curie temperature,and oxidation *** absorption bandwidth maintains between 593 and 691 MHz from-50 to 150℃.This work offers a new and tunable strategy toward modulating the electromagnetic genes for temperature-stable ultra-broadband megahertz EMW absorption.
This paper proposes a novel impulsive thrust strategy guided by optimal continuous thrust strategy to address two-player orbital pursuit-evasion game under impulsive thrust *** strategy seeks to enhance the interpreta...
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This paper proposes a novel impulsive thrust strategy guided by optimal continuous thrust strategy to address two-player orbital pursuit-evasion game under impulsive thrust *** strategy seeks to enhance the interpretability of impulsive thrust strategy by integrating it within the framework of differential game in traditional continuous ***,this paper introduces an impulse-like constraint,with periodical changes in thrust amplitude,to characterize the impulsive thrust ***,the game with the impulse-like constraint is converted into the two-point boundary value problem,which is solved by the combined shooting and deep learning method proposed in this *** learning and numerical optimization are employed to obtain the guesses for unknown terminal adjoint variables and the game terminal ***,the accurate values are solved by the shooting method to yield the optimal continuous thrust strategy with the impulse-like ***,the shooting method is iteratively employed at each impulse decision moment to derive the impulsive thrust strategy guided by the optimal continuous thrust *** examples demonstrate the convergence of the combined shooting and deep learning method,even if the strongly nonlinear impulse-like constraint is *** effect of the impulsive thrust strategy guided by the optimal continuous thrust strategy is also discussed.
The demand for energy-efficient and environmental-friendly power grid construction has made the exploitation of bio-based electrical epoxy resins with excellent properties increasingly *** work developed the bio-based...
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The demand for energy-efficient and environmental-friendly power grid construction has made the exploitation of bio-based electrical epoxy resins with excellent properties increasingly *** work developed the bio-based electrotechnical epoxy resins based on ***-performance epoxy resin(DGEMT)with a double crosslinked points and its composites(Al_(2)O_(3)/DGEMT)were obtained taking advantages of the two bifunctional groups(allyl and phenolic hydroxyl groups)of *** from the distinctive structure of DGEMT,the Al_(2)O_(3)/DGEMT composites exhibited the advantages of intrinsically high thermal conductivity,high insulation,and low dielectric *** AC breakdown strength and thermal conductivity of Al_(2)O_(3)/DGEMT composites were 35.5 kV/mm and 1.19 W·m-1·K-1,respectively,which were 15.6%and 52.6%higher than those of petroleum-based composites(Al_(2)O_(3)/DGEBA).And its dielectric loss tanδ=0.0046 was 20.7%lower than that of Al_(2)O_(3)/***,the mechanical,thermal and processing properties of Al_(2)O_(3)/DGEMT are fully comparable to those of Al_(2)O_(3)/*** work confirms the feasibility of manufacturing environmentally friendly power equipment using bio-based epoxy resins,which has excellent engineering applications.
Deep sea,with rich oil,gas,and mineral resources,plays an increasingly crucial role in scientific and in-dustrial ***,the highly corrosive feature of deep sea hinders further exploration and devel-opment,which require...
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Deep sea,with rich oil,gas,and mineral resources,plays an increasingly crucial role in scientific and in-dustrial ***,the highly corrosive feature of deep sea hinders further exploration and devel-opment,which requires metal materials with robust corrosion *** review covers an in-depth and all-around overview of the up-to-date advances in corrosion and protection of metals in deep-sea ***,the unique characteristics of deep-sea environment are summarized in ***-sequently,the corrosion performances of metals in both in situ and simulated deep-sea environments are illustrated ***,corrosion prevent strategies of metals,including sacrificial anode protection,organic coatings,as well as coatings achieved by physical vapor deposition(PVD coatings),are ***,we outline current challenges and development trends of corrosion and protection of metals in deep-sea environment in the *** purpose of this review is not only to summarize the recent progress on metal corrosion and protection in deep sea,but also to aid us in understanding them more comprehensively and deeply in a short time,so as to boost their fast development.
All extant cellular organisms derive from a common ancestor, which can be illustrated by the universality of many pivotal metabolic traits, including the utilization of ATP as an energy currency and multiple mechanism...
All extant cellular organisms derive from a common ancestor, which can be illustrated by the universality of many pivotal metabolic traits, including the utilization of ATP as an energy currency and multiple mechanisms processing the genetic information flow as demonstrated by the Central Dogma of biology (Theobald, 2010; Hug et al., 2016).
The Pacific oyster Crassostrea gigas,one of the most exploited molluscs in the world,has suffered from massive mortality in recent decades,and the occurrence mechanisms have not been well *** this study,to reveal the ...
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The Pacific oyster Crassostrea gigas,one of the most exploited molluscs in the world,has suffered from massive mortality in recent decades,and the occurrence mechanisms have not been well *** this study,to reveal the relationship of associated microbiota to the fitness of oysters,temporal dynamics of microbiota in the gill,hemolymph,and hepatopancreas of *** during April 2018-January 2019 were investigated by 16 S rRNA gene *** microbiota in *** exhibited tissue heterogeneity,of which Spirochaetaceae was dominant in the gill and hemolymph while Mycoplasmataceae enriched in the ***-occurrence network demonstrated that the gill microbiota exhibited higher inter-taxon connectivity while the hemolymph microbiota had more *** richness(Chao 1 index)and diversity(Shannon index)of microbial community in each tissue showed no significant seasonal variations,except for the hepatopancreas having a higher richness in the ***,beta diversity analysis indicated a relatively stable microbiota in each tissue during the sampling period,showing relative abundance of the dominant taxa exhibiting temporal *** indicate that the microbial community in *** showed a tissue-specific stability with temporal dynamics in the composition,which might be essential for the tissue functioning and environmental adaption in *** work provides a baseline microbiota in *** and is helpful for the understanding of host-microbiota interaction in oysters.
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