In order to reasonably and accurately evaluate the health status of the switch machine, a health stage division method of switch machine combining BrayCurtis distance and Fisher optimal segmentation is proposed. First...
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In order to reasonably and accurately evaluate the health status of the switch machine, a health stage division method of switch machine combining BrayCurtis distance and Fisher optimal segmentation is proposed. First, the power curve of switch machine is divided into five sections, and eight time-domain characteristic parameters of each section are extracted. Second, the characteristic parameters with the largest correlation between fifteen dimensions and state of the switch machine are selected by using the Holder coefficient method as the input of Bray-Curtis distance algorithm, using Bray-Curtis distance to calculate health index(HI), which represents health state of switch machine. Finally, HI curve is divided by Fisher optimal segmentation method,and the optimal number of health stages of switch machine is determined to be three, and HI interval and threshold of each health stage are obtained. The effectiveness of this method is verified by 4382 sets of on-site switch machine data experiments. The experimental results show that the health index curve calculated by BrayCurtis distance can accurately represent the health status of the switch machine. Compared with Frechet distance and European distance, this method has better performance in tendency, robustness, and runtime. Combining with Fisher optimal segmentation method, it can reasonably and effectively divide the health stage of the switch machine, providing some support for the on-site judgment of the health status of the switch machine.
Time based maintenance(TBM)and condition based maintenance(CBM)are widely applied in many large wind farms to optimize the maintenance issues of wind turbine gearboxes,however,these maintenance strategies do not take ...
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Time based maintenance(TBM)and condition based maintenance(CBM)are widely applied in many large wind farms to optimize the maintenance issues of wind turbine gearboxes,however,these maintenance strategies do not take into account environmental benefits during full life cycle such as carbon emissions ***,this article proposes a carbon emissions computing model for preventive maintenance activities of wind turbine gearboxes to solve the *** on the change of the gearbox state during operation and the influence of external random factors on the gearbox state,a stochastic differential equation model(SDE)and corresponding carbon emission model are established,wherein SDE is applied to model the evolution of the device state,whereas carbon emission is used to implement carbon emissions *** simulation results indicate that the proposed preventive maintenance cannot ensure reliable operation of wind turbine gearboxes but reduce carbon emissions during their *** with TBM,CBM minimizes unit carbon emissions without influencing reliable operation,making it an effective maintenance method.
Gesture recognition has diverse application prospects in the field of human-computer ***,gesture recognition devices based on strain sensors have achieved remarkable results,among which liquid metal materials have con...
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Gesture recognition has diverse application prospects in the field of human-computer ***,gesture recognition devices based on strain sensors have achieved remarkable results,among which liquid metal materials have considerable advantages due to their high tensile strength and *** improve the detection sensitivity of liquid metal strain sensors,a sawtooth-enhanced bending sensor is proposed in this *** with the results from previous studies,the bending sensor shows enhanced resistance *** addition,combined with machine learning algorithms,a gesture recognition glove based on the sawtooth-enhanced bending sensor is also fabricated in this study,and various gestures are accurately *** the fields of human-computer interaction,wearable sensing,and medical health,the sawtooth-enhanced bending sensor shows great potential and can have wide application prospects.
Flapping-wing flying robots(FWFRs),especially large-scale robots,have unique advantages in flight efficiency,load capacity,and bionic ***,they have significant potential in environmental detection,disaster rescue,and ...
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Flapping-wing flying robots(FWFRs),especially large-scale robots,have unique advantages in flight efficiency,load capacity,and bionic ***,they have significant potential in environmental detection,disaster rescue,and anti-terrorism explosion ***,at present,most FWFRs are operated *** have a certain autonomous ability limited to the cruise stage but not the complete flight *** factors make an FWFR unable to give full play to the advantages of flapping-wing flight to perform autonomous flight *** paper proposed an autonomous flight control method for FWFRs covering the complete process,including the takeoff,cruise,and landing ***,the flight characteristics of the mechanical structure of the robot are ***,dedicated control strategies are designed following the different control requirements of the defined ***,a hybrid control law is presented by combining different control strategies and ***,the proposed method and system are validated through outdoor flight experiments of the HIT-Hawk with a wingspan of 2.3 m,in which the control algorithm is integrated with an onboard embedded *** experimental results show that this robot can fly autonomously during the complete flight *** mean value and root mean square(RMS)of the control error are less than 0.8409 and 3.054 m,respectively,when it flies around a circle in an annular area with a radius of 25 m and a width of 10 m.
To improve system flexibility and reliability, mobile energy storage (MES) is treated as a unified dispatching resource of the active distribution network (ADN) to participate in operation optimization and power suppl...
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Identifying workers’construction activities or behaviors can enable managers to better monitor labor efficiency and construction ***,current activity analysis methods for construction workers rely solely on manual ob...
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Identifying workers’construction activities or behaviors can enable managers to better monitor labor efficiency and construction ***,current activity analysis methods for construction workers rely solely on manual observations and recordings,which consumes considerable time and has high labor *** have focused on monitoring on-site construction activities of ***,when multiple workers are working together,current research cannot accu rately and automatically identify the construction *** research proposes a deep learning framework for the automated analysis of the construction activities of multiple *** this framework,multiple deep neural network models are designed and used to complete worker key point extraction,worker tracking,and worker construction activity *** designed framework was tested at an actual construction site,and activity recognition for multiple workers was performed,indicating the feasibility of the framework for the automated monitoring of work efficiency.
This paper studies the dynamic event-triggered leader-follower consensus of nonlinear multi-agent systems(MASs)under directed weighted graph containing a directed spanning tree,and also considers the effects of distur...
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This paper studies the dynamic event-triggered leader-follower consensus of nonlinear multi-agent systems(MASs)under directed weighted graph containing a directed spanning tree,and also considers the effects of disturbances and leader of non-zero control inputs in the ***,a novel distributed control protocol is designed for uncertain disturbances and leader of non-zero control inputs in ***,a novel dynamic event-triggered control(DETC)strategy is proposed,which eliminates the need for continuous communication between agents and reduces communication resources between *** introducing dynamic thresholds,the complexity of excluding Zeno behavior within the system is ***,the effectiveness of the proposed theory is validated through numerical simulation.
This paper is concerned with the finite-time dissipative synchronization control problem of semi-Markov switched cyber-physical systems in the presence of packet losses, which is constructed by the Takagi–Sugeno fuzz...
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This paper is concerned with the finite-time dissipative synchronization control problem of semi-Markov switched cyber-physical systems in the presence of packet losses, which is constructed by the Takagi–Sugeno fuzzy model. To save the network communication burden, a distributed dynamic event-triggered mechanism is developed to restrain the information update. Besides, random packet dropouts following the Bernoulli distribution are assumed to occur in sensor to controller channels, where the triggered control input is analyzed via an equivalent method containing a new stochastic variable. By establishing the mode-dependent Lyapunov–Krasovskii functional with augmented terms, the finite-time boundness of the error system limited to strict dissipativity is studied. As a result of the help of an extended reciprocally convex matrix inequality technique, less conservative criteria in terms of linear matrix inequalities are deduced to calculate the desired control gains. Finally, two examples in regard to practical systems are provided to display the effectiveness of the proposed theory.
Hydrogen energy plays an important role in achieving carbon neutralization,and plasma induced hydrogen is an effective production *** challenge is how to guarantee high efficiency operation with wide power output rang...
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Hydrogen energy plays an important role in achieving carbon neutralization,and plasma induced hydrogen is an effective production *** challenge is how to guarantee high efficiency operation with wide power output range of the RF inverter system used to generate the *** this paper,a multi-module parallel topology of a high-frequency inverter is analyzed,in which the power combining network can maintain the soft switching characteristics of the inverter modules.A control method of"ON/OFF+phase shift"is adopted to broaden the output power range of the *** equivalent impedances of different modules are analyzed in detail.A four-module 13.56 MHz high-frequency inverter prototype is built and *** results show that the inverter can operate at high efficiency and wide output power range with efficiency improved by at least 5%compared with the traditional parameter design method without considering the effect of paralleled modules.
The m-phase LLC resonant converter serves as an effective solution for reducing current stress and enabling highpower DC-DC conversion applications. However, variations in component parameters within the resonant tank...
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