Event region detection is the important application for wireless sensor networks（WSNs）, where the existing faulty sensors would lead to drastic deterioration of network quality of service.Considering single-moment n...Event region detection is the important application for wireless sensor networks（WSNs）, where the existing faulty sensors would lead to drastic deterioration of network quality of service.Considering single-moment nodes fault-tolerance, a novel distributed fault-tolerant detection algorithm named distributed fault-tolerance based on weighted distance（DFWD） is proposed, which exploits the spatial correlation among sensor nodes and their redundant information.In sensor networks, neighborhood sensor nodes will be endowed with different relative weights respectively according to the distances between them and the central node.Having syncretized the weighted information of dual-neighborhood nodes appropriately, it is reasonable to decide the ultimate status of the central sensor node.Simultaneously, readings of faulty sensors would be corrected during this process.Simulation results demonstrate that the DFWD has a higher fault detection accuracy compared with other algorithms, and when the sensor fault probability is 10%, the DFWD can still correct more than 91% faulty sensor nodes, which significantly improves the performance of the whole sensor network.展开更多
Fault-tolerance is increasingly significant for large-scale storage systems in which Byzantine failure of storage nodes may happen. Traditional Byzantine Quorum systems that tolerate Byzantine failures by using replic...Fault-tolerance is increasingly significant for large-scale storage systems in which Byzantine failure of storage nodes may happen. Traditional Byzantine Quorum systems that tolerate Byzantine failures by using replication have two main limitations： low space-efficiency and static quorum variables. We propose an Erasure-code Byzantine Fault-tolerance Quorum that can provide high reliability with far lower storage overhead than replication by adopting erasure code as redundancy scheme. Through read/write operations of clients and diagnose operation of supervisor, our Quorum system can detect Byzantine nodes, and dynamically adjust system size and fault threshold. Simulation results show that our method improves performance for the Quorum with relatively small quorums.展开更多
Aiming to the reliable estimates of the ionosphere differential corrections for the satellite navigation system in the presence of the ionosphere anomaly, a fault-tolerance estimating method, which is based on the dis...Aiming to the reliable estimates of the ionosphere differential corrections for the satellite navigation system in the presence of the ionosphere anomaly, a fault-tolerance estimating method, which is based on the distributed Kalman filtering, is proposed. The method utilizes the parallel sub-filters for estimating the ionosphere differential corrections. Meanwhile, an infinite norm （IN） method is proposed for the detection of the ionosphere irregularity in the filter processing. Once the anomaly is detected, the sub-filter contaminated by the anomaly measurements will be excluded to ensure the reliability of the estimates. The simulation is conducted to validate the method and the results indicate that the anomaly can be found timely due to the novel fault detection method based on the infinite norm. Because of the parallel sub-filter architecture, the measurements are classified by the spatial distribution so that the ionosphere anomaly can be positioned and excluded more easily. Thus, the method can provide the robust and accurate ionosphere differential corrections.展开更多
The potential benefits of hybrid-electric or all-electric propulsion have led to a growing interest in this topic over the past decade.Preliminary design of propulsion systems and innovative configurations has been ex...The potential benefits of hybrid-electric or all-electric propulsion have led to a growing interest in this topic over the past decade.Preliminary design of propulsion systems and innovative configurations has been extensively discussed in literature,but steps towards higher levels of technological readiness,optimisation algorithms based on reliable weight estimation and simulationbased mission analysis are required.This paper focuses on the integration of a method for evaluating the lateral-directional controllability of an aircraft within a design chain that integrates aero-propulsive interactions,accurate modelling of the fuel system,and mid-fidelity estimation of the structural weight.Furthermore,the present work proposes a strategy for powerplant management in scenarios with an inoperative chain element.Benefits of hybrid-electric propulsion on the design of the vertical tail plane are evaluated involving the analysis of multiple failure scenarios and certification requirements.The proposed application concerns a commuter aircraft.展开更多
The prerequisite for the existing protocols' correctness is that protocols can be normally operated under the normal conditions, rather than dealing with abnormal conditions. In other words, protocols with the fau...The prerequisite for the existing protocols' correctness is that protocols can be normally operated under the normal conditions, rather than dealing with abnormal conditions. In other words, protocols with the fault-tolerance can not be provided when some fault occurs. This paper discusses the self fault-tolerance of protocols. It describes some concepts and methods for achieving self fault-tolerance of protocols. Meanwhile, it provides a case study, investigates a typical protocol that does not satisfy the self fault-tolerance, and gives a new redesign version of this existing protocol using the proposed approach.展开更多
Unexpected scenarios often occur during typhoon response,which is likely to cause the failure of evacuation vehicle dispatching and other preparedness plans.To solve this problem,a vehicle dispatching plan selecting m...Unexpected scenarios often occur during typhoon response,which is likely to cause the failure of evacuation vehicle dispatching and other preparedness plans.To solve this problem,a vehicle dispatching plan selecting method based on fault-tolerance analysis is proposed,which considers the bounded rationality of emergency decision-makers.The method improves the capability of responding to unexpected scenarios by increasing backup resources.First,under the expected scenarios,a bi-level programming model for arranging the quantities of each type of vehicle and their routes is established,with the goal of minimizing the expected total evacuation time.A corresponding solving algorithm is designed.Second,possible unexpected scenarios are preset by integrating local and non-local historical experiences,and the scenario influences on vehicle dispatching constraints are analyzed.Third,under unexpected scenarios,a fault-tolerance plan set is established considering the failure risk of vehicle dispatching and fault-tolerant cost.The optimal plan is selected by calculating and ranking fault-tolerant rates.Finally,a case study in Shenzhen,China is provided to verify the reasonability and effectiveness of the method.The results show that the proposed method can help discover and address the‘fault’of vehicle dispatching plans during emergency preparedness and thus improve evacuation capabilities in emergency response.The proposed method can be used to develop evacuation vehicle dispatching planning methods with comprehensive scenario adaptability and a precisely improved capability.展开更多
To solve the problem of in-flight actuator faults and parameter uncertainties for multiple Unmanned Aerial Vehicles(UAVs),and reduce the communication and computational resource consumption of multiple UAVs,a Fraction...To solve the problem of in-flight actuator faults and parameter uncertainties for multiple Unmanned Aerial Vehicles(UAVs),and reduce the communication and computational resource consumption of multiple UAVs,a Fraction-Order(FO)sliding-mode Fault-Tolerant Cooperative Control(FTCC)strategy is proposed for multiple UAVs based on Event-Triggered Communication Mechanism(ET-COM-M)and Event-Triggered Control Mechanism(ET-CON-M).First,by considering the limited communication bandwidth of multiple UAVs in formation,an ET-COM-M is designed to significantly reduce communication times.Then,a distributed observer is skillfully constructed to estimate the reference signals for follower UAVs.Moreover,the adaptive strategy is incorporated into the Radial Basis Function Neural Network(RBFNN)to learn the lumped unknown terms for handling bias actuator faults and parameter uncertainties.Besides,the Nussbaum method is used to deal with the loss-of-effectiveness faults.To further achieve the refined control performance against faults,FO calculus is artfully integrated into the sliding-mode control protocol with ET-CON-M.Finally,Zeno behavior is excluded by rigorous theoretical analysis and Lyapunov stability is proved to show the effectiveness of the designed FTCC strategy.Simulation results show that the designed FTCC strategy with Event-Triggered Mechanism(ETM)can guarantee the safety of multiple UAVs and simultaneously reduce the communication and control frequencies,making the developed control scheme applicable in engineering.展开更多
This paper is dedicated to solving the problem of adaptive fuzzy fault-tolerant tracking control for a class of time-varying high-order uncertain nonlinear systems.The motivation comes from how to construct a compact ...This paper is dedicated to solving the problem of adaptive fuzzy fault-tolerant tracking control for a class of time-varying high-order uncertain nonlinear systems.The motivation comes from how to construct a compact set large enough in which the approximation of any unknown continuous function by a fuzzy logic system(FLS)is effective while compensating sensor/actuator faults and external disturbances.The difficulty is to verify the boundedness of closed-loop signals on the constructed compact set and to reduce the number of the variables of the fuzzy membership functions as many as possible.By a new lemma,linear/nonlinear terms are introduced in adaptive laws to dominate unknown residual terms.With adding a power integrator method,a unified fault-tolerant controller is designed to drive the tracking error to converge to a small compact set of the origin within a fixed time,regardless of whether the system suffers from faults and disturbances.Superior to the existing results,in the presence of time-varying factors the scheme of this paper clarifies the logical relationship between the compactness of the approximation and the boundedness of the state variables.Finally,the application of control strategy is demonstrated by numerical/practical examples.展开更多
This paper is concerned with adaptive consensus tracking control of nonlinear multi-agent systems with actuator faults and unknown nonidentical control directions under double semi-Markovian switching topologies.Consi...This paper is concerned with adaptive consensus tracking control of nonlinear multi-agent systems with actuator faults and unknown nonidentical control directions under double semi-Markovian switching topologies.Considering the complex working environment and the stability differences in communication links between leaders and followers,a double semi-Markov process is first introduced to describe the random switching of communication topologies in the leader-follower structure.In order to address challenges from the unknown nonidentical control directions and partial loss of effectiveness actuator faults,a completely independent parameter is introduced into the Nussbaum function to overcome the inherent obstacle of mutual cancellation and avoid the rapid growth rate.Considering only the state information of agents is transmitted among the agents,an adaptive distributed fault-tolerant consensus tracking control is proposed based on the double semi-Markovian switching topologies using the designed Nussbaum function.Furthermore,the stability of the closed-loop nonlinear multi-agent systems is analyzed using contradiction argument and Lyapunov theorem,from which the asymptotic consensus tracking in mean square sense can be obtained.A numerical simulation example is provided to verify the effectiveness of the proposed algorithm.展开更多
To address the finite-time tracking control problem for fractional-order nonlinear systems(FONSs) with actuator faults and external disturbance,a novel strategy of the finite-time adaptive fuzzy fault-tolerant control...To address the finite-time tracking control problem for fractional-order nonlinear systems(FONSs) with actuator faults and external disturbance,a novel strategy of the finite-time adaptive fuzzy fault-tolerant controller is presented in this paper by utilizing the finite-time stability theory and fractional-order dynamic surface control scheme combined with backstepping method.A new lemma is developed for analyzing the finite-time stability of FONSs in terms of fractional differential inequality,which modifies some existing results.Fuzzy logic systems are adopted to identify unknown nonlinear characteristics in FONS.In order to compensate for the influence of unknown external disturbance and estimation error for fuzzy logic systems,an auxiliary function is employed to estimate the upper bound of parameters online.Furthermore,a global coordinate transformation is first introduced initially to decouple the fractional-order dynamic system of a specific class of underactuated single-link flexible manipulator systems,thereby transforming it into lower triangular systems.Simulation analyses and experimental results verify the feasibility and effectiveness of finite-time tracking control algorithm.展开更多
Owing to the multi-degree-of-freedom characteristics and inherent fault-tolerant capacity,six-phase motors have been widely adopted in high-power applications,such as electric vehicle propulsion and aerospace systems....Owing to the multi-degree-of-freedom characteristics and inherent fault-tolerant capacity,six-phase motors have been widely adopted in high-power applications,such as electric vehicle propulsion and aerospace systems.This paper presents the fault-tolerant control strategy of symmetrical six-phase permanent magnet synchronous motor(SSPMSM)under an isolated neutral point topology and proposes a fault diagnosis scheme based on joint diagnosis of multiple variables.First,two mathematical models of SSPMSM and their relationship are established.Subsequently,the current vectors in the torque subspace and harmonic subspace of the two winding sets under fault conditions are analyzed,and the cause of post-fault torque ripple is explained as resulting from controller conflict.In addition,a multivariate fault diagnosis scheme based on voltage threshold in the x-y subspace and current trajectory characteristics in theα-βsubspace is proposed to enhance the diagnostic accuracy.Finally,the feasibility and stability of the proposed control and diagnosis methods are verified by experiments.展开更多
The cooperation of different processes may be lost by mistake when a protocol is executed. The protocol cannot be normally operated under this condition. In this paper,the self fault-tolerance of protocols is discuss...The cooperation of different processes may be lost by mistake when a protocol is executed. The protocol cannot be normally operated under this condition. In this paper,the self fault-tolerance of protocols is discussed, and a semanticsbased approach for achieving self fault-tolerance of protocols is presented. Some main characteristics of self fault-tolerance of protocols concerning liveness, nontermination and infinity are also presented. Meanwhile, the sufficient and necessary conditions for achieving self fault-tolerance of protocols are given. Finally, a typical protocol that does not satisfy the self fault-tolerance is investigated, and a new redesign version of this existing protocol using the proposed approach is given.展开更多
The cross-domain capabilities of aerial-aquatic vehicles(AAVs)hold significant potential for future airsea integrated combat operations.However,the failure rate of AAVs is higher than that of unmanned systems operatin...The cross-domain capabilities of aerial-aquatic vehicles(AAVs)hold significant potential for future airsea integrated combat operations.However,the failure rate of AAVs is higher than that of unmanned systems operating in a single medium.To ensure the reliable and stable completion of tasks by AAVs,this paper proposes a tiltable quadcopter AAV to mitigate the potential issue of rotor failure,which can lead to high-speed spinning or damage during cross-media transitions.Experimental validation demonstrates that this tiltable quadcopter AAV can transform into a dual-rotor or triple-rotor configuration after losing one or two rotors,allowing it to perform cross-domain movements with enhanced stability and maintain task completion.This enhancement significantly improves its fault tolerance and task reliability.展开更多
Fault tolerance is essential for reliable and sustainable smart city infrastructure.Interconnected IoT systems must function under frequent faults,limited resources,and complex conditions.Existing research covers vari...Fault tolerance is essential for reliable and sustainable smart city infrastructure.Interconnected IoT systems must function under frequent faults,limited resources,and complex conditions.Existing research covers various fault-tolerant methods.However,current reviews often lack system-level critique and multidimensional analysis.This study provides a structured review of fault tolerance strategies across layered IoT architectures in smart cities.It evaluates fault detection,containment,and recovery techniques using specific metrics.These include fault visibility,propagation depth,containment score,and energy-resilience trade-offs.The analysis uses comparative tables,architecture-aware discussions,and conceptual plots.It investigates the impact of fault tolerance on decision-making in Supervisory Control And Data Acquisition(SCADA)systems,sensor networks,and real-time controllers.Simulation results and logic-based design support the relationships between evaluation metrics.Findings show a common reliance on redundancy and reactive methods.Many techniques fail to address cross-layer propagation,context-aware adaptation,and silent fault impact on user trust.The study combines these overlooked aspects into a system-level framework.This survey identifies performance bottlenecks and supports the design of adaptive,energy-efficient,and transparent IoT systems.The results contribute to bridging technical reliability with public trust,supporting scalable and responsible smart city development.展开更多
The field modulation effect has been proposed and investigated in various electric machine topologies.Among them,permanent magnet vernier machines(PMVMs)have attained intensive research due to the high torque density ...The field modulation effect has been proposed and investigated in various electric machine topologies.Among them,permanent magnet vernier machines(PMVMs)have attained intensive research due to the high torque density and simple structure.However,the performance of PMVMs in terms of fault tolerance is seldom mentioned.This article proposes a novel dual 3-phase fault-tolerant PMVM with segregated concentric windings.Benefiting from the field modulation effect,the PMVM can generate high torque with low PM flux.The low PM flux also implies small fault currents in the short-circuit case.Therefore,the PMVM exhibits inherent good fault-tolerant capability without sacrificing torque performance.Two independent 3-phase modular winding sets are adopted to improve redundancy.To realize the physical and electrical isolation,each winding set is controlled by a standard 3-phase inverter.The healthy performance and fault tolerance of the proposed machine are evaluated by finite element analysis and verified by experimental tests.The results infer its advantages in healthy conditions and various fault scenarios,including open-circuit,short-circuit,and interturn short-circuit conditions.展开更多
The operating environment of the diesel engine air path system is complex and may be affected by external random disturbances.Potentially leading to faults.This paper addresses the fault-tolerant control problem of th...The operating environment of the diesel engine air path system is complex and may be affected by external random disturbances.Potentially leading to faults.This paper addresses the fault-tolerant control problem of the diesel engine air path system,assuming that the system may simultaneously be affected by actuator faults and external random disturbances,a disturbance observer-based sliding mode controller is designed.Through the linear matrix inequality technique for solving observer and controller gains,optimal gain matrices can be obtained,eliminating the manual adjustment process of controller parameters and reducing the chattering phenomenon of the sliding mode surface.Finally,the effectiveness of the proposed method is verified through simulation analysis.展开更多
This paper investigates the issue of fault-tolerant control for swarm systems subject to switched graphs,actuator faults and obstacles.A geometric-based partial differential equation(PDE)framework is proposed to unify...This paper investigates the issue of fault-tolerant control for swarm systems subject to switched graphs,actuator faults and obstacles.A geometric-based partial differential equation(PDE)framework is proposed to unify collision-free trajectory generation and fault-tolerant control.To deal with the fault-induced force imbalances,the Riemannian metric is proposed to coordinate nominal controllers and the global one.Then,Riemannianbased trajectory length optimization is solved by gradient's dynamic model-heat flow PDE,under which a feasible trajectory satisfying motion constraints is achieved to guide the faulty system.Such virtual control force emerges autonomously through this metric adjustments.Further,the tracking error is rigorously proven to be exponential boundedness.Simulation results confirm the validity of these theoretical findings.展开更多
Hydraulic-electric systems are widely utilized in various applications.However,over time,these systems may encounter random faults such as loose cables,ambient environmental noise,or sensor aging,leading to inaccurate...Hydraulic-electric systems are widely utilized in various applications.However,over time,these systems may encounter random faults such as loose cables,ambient environmental noise,or sensor aging,leading to inaccurate sensor readings.These faults may result in system instability or compromise safety.In this paper,we propose a fault compensation control system to mitigate the effects of sensor faults and ensure system safety.Specifically,we utilize the pressure sensor within the system to implement the control process and evaluate performance based on the piston position.First,we develop a mathematical model to identify optimal parameters for the fault estimation model based on the Lyapunov stability principle.Next,we design an unknown input observer that estimates the state vector and detects pressure sensor faults using a linear matrix inequality optimization algorithm.The estimated pressure faults are incorporated into the fault compensation control system to counteract their effects via a fault residual coefficient.The discrepancy between the feedback state and the estimated state determines this coefficient.We assess the piston position’s performance through pressure control to evaluate the proposed model’s effectiveness.Finally,the system simulation results are analyzed to validate the efficiency of the proposed model.When a pressure sensor fault occurs,the proposed approach effectively minimizes position control errors,enhancing overall system stability.When a pressure sensor fault occurs,the proposed model compensates for the fault to mitigate the impact of pressure problem,thereby enhancing the position control quality of the EHA system.The fault compensation method ensures over 90%system performance,with its effectiveness becoming more evident under pressure sensor faults.展开更多
The problem of trajectory tracking for a class of differentially driven wheeled mobile robots(WMRs)under partial loss of the effectiveness of the actuated wheels is investigated in this paper.Such actuator faults may ...The problem of trajectory tracking for a class of differentially driven wheeled mobile robots(WMRs)under partial loss of the effectiveness of the actuated wheels is investigated in this paper.Such actuator faults may cause the loss of strong controllability of the WMR,such that the conventional fault-tolerant control strategies unworkable.In this paper,a new mixed-gain adaption scheme is devised,which is adopted to adapt the gain of a decoupling prescribed performance controller to adaptively compensate for the loss of the effectiveness of the actuators.Different from the existing gain adaption technique which depends on both the barrier functions and their partial derivatives,ours involves only the barrier functions.This yields a lower magnitude of the resulting control signals.Our controller accomplishes trajectory tracking of the WMR with the prescribed rate and accuracy even in the faulty case,and the control design relies on neither the information of the WMR dynamics and the actuator faults nor the tools for function approximation,parameter identification,and fault detection or estimation.The comparative simulation results justify the theoretical findings.展开更多
Permanent-magnet synchronous machines(PMSMs)are widely used in robotics,rail transportation,and electric vehicles owing to their high power density,high efficiency,and high power factor.However,PMSMs often operate in ...Permanent-magnet synchronous machines(PMSMs)are widely used in robotics,rail transportation,and electric vehicles owing to their high power density,high efficiency,and high power factor.However,PMSMs often operate in harsh environments,where critical components such as windings and permanent magnets(PMs)are susceptible to failures.These faults can lead to a significant degradation in performance,posing substantial challenges to the reliable operation of PMSMs.This paper presents a comprehensive review of common fault types in PMSMs,along with their corresponding fault diagnosis and fault-tolerant control strategies.The underlying mechanisms of typical faults are systematically analyzed,followed by a detailed comparison of various diagnostic and fault-tolerant control methods to evaluate their respective advantages and limitations.Finally,the review concludes by identifying key research gaps in PMSM fault diagnosis and fault-tolerant control,while proposing potential future directions for advancing this field.展开更多
基金supported by the National Science Foundation for Outstanding Young Scientists (60425310)the Science Foundation for Post-doctoral Scientists of Central South University (2008)
文摘Event region detection is the important application for wireless sensor networks（WSNs）, where the existing faulty sensors would lead to drastic deterioration of network quality of service.Considering single-moment nodes fault-tolerance, a novel distributed fault-tolerant detection algorithm named distributed fault-tolerance based on weighted distance（DFWD） is proposed, which exploits the spatial correlation among sensor nodes and their redundant information.In sensor networks, neighborhood sensor nodes will be endowed with different relative weights respectively according to the distances between them and the central node.Having syncretized the weighted information of dual-neighborhood nodes appropriately, it is reasonable to decide the ultimate status of the central sensor node.Simultaneously, readings of faulty sensors would be corrected during this process.Simulation results demonstrate that the DFWD has a higher fault detection accuracy compared with other algorithms, and when the sensor fault probability is 10%, the DFWD can still correct more than 91% faulty sensor nodes, which significantly improves the performance of the whole sensor network.
基金Supported by the National Natural Science Foun-dation of China (60373088)
文摘Fault-tolerance is increasingly significant for large-scale storage systems in which Byzantine failure of storage nodes may happen. Traditional Byzantine Quorum systems that tolerate Byzantine failures by using replication have two main limitations： low space-efficiency and static quorum variables. We propose an Erasure-code Byzantine Fault-tolerance Quorum that can provide high reliability with far lower storage overhead than replication by adopting erasure code as redundancy scheme. Through read/write operations of clients and diagnose operation of supervisor, our Quorum system can detect Byzantine nodes, and dynamically adjust system size and fault threshold. Simulation results show that our method improves performance for the Quorum with relatively small quorums.
基金National Basic Research Program of China (2010CB731800)
文摘Aiming to the reliable estimates of the ionosphere differential corrections for the satellite navigation system in the presence of the ionosphere anomaly, a fault-tolerance estimating method, which is based on the distributed Kalman filtering, is proposed. The method utilizes the parallel sub-filters for estimating the ionosphere differential corrections. Meanwhile, an infinite norm （IN） method is proposed for the detection of the ionosphere irregularity in the filter processing. Once the anomaly is detected, the sub-filter contaminated by the anomaly measurements will be excluded to ensure the reliability of the estimates. The simulation is conducted to validate the method and the results indicate that the anomaly can be found timely due to the novel fault detection method based on the infinite norm. Because of the parallel sub-filter architecture, the measurements are classified by the spatial distribution so that the ionosphere anomaly can be positioned and excluded more easily. Thus, the method can provide the robust and accurate ionosphere differential corrections.
基金The ELICA project leading to this application has received funding from the Clean Sky 2 Joint Undertaking(JU)(No.864551)The JU receives support from the European Union’s Horizon 2020 research and innovation programme。
文摘The potential benefits of hybrid-electric or all-electric propulsion have led to a growing interest in this topic over the past decade.Preliminary design of propulsion systems and innovative configurations has been extensively discussed in literature,but steps towards higher levels of technological readiness,optimisation algorithms based on reliable weight estimation and simulationbased mission analysis are required.This paper focuses on the integration of a method for evaluating the lateral-directional controllability of an aircraft within a design chain that integrates aero-propulsive interactions,accurate modelling of the fuel system,and mid-fidelity estimation of the structural weight.Furthermore,the present work proposes a strategy for powerplant management in scenarios with an inoperative chain element.Benefits of hybrid-electric propulsion on the design of the vertical tail plane are evaluated involving the analysis of multiple failure scenarios and certification requirements.The proposed application concerns a commuter aircraft.
基金This project was supported by the National Natural Science Foundation of China and the Natural Science Foundation of Hubei Prov
文摘The prerequisite for the existing protocols' correctness is that protocols can be normally operated under the normal conditions, rather than dealing with abnormal conditions. In other words, protocols with the fault-tolerance can not be provided when some fault occurs. This paper discusses the self fault-tolerance of protocols. It describes some concepts and methods for achieving self fault-tolerance of protocols. Meanwhile, it provides a case study, investigates a typical protocol that does not satisfy the self fault-tolerance, and gives a new redesign version of this existing protocol using the proposed approach.
基金supported by the Young Scientists Fund of the National Natural Science Foundation of China(No.72404232)the Major Research Project of National Natural Science Foundation of China named“Big data Driven Management and Decision-making Research”(No.91746207)Fujian Provincial Natural Science Foundation(No.2023J05011).
文摘Unexpected scenarios often occur during typhoon response,which is likely to cause the failure of evacuation vehicle dispatching and other preparedness plans.To solve this problem,a vehicle dispatching plan selecting method based on fault-tolerance analysis is proposed,which considers the bounded rationality of emergency decision-makers.The method improves the capability of responding to unexpected scenarios by increasing backup resources.First,under the expected scenarios,a bi-level programming model for arranging the quantities of each type of vehicle and their routes is established,with the goal of minimizing the expected total evacuation time.A corresponding solving algorithm is designed.Second,possible unexpected scenarios are preset by integrating local and non-local historical experiences,and the scenario influences on vehicle dispatching constraints are analyzed.Third,under unexpected scenarios,a fault-tolerance plan set is established considering the failure risk of vehicle dispatching and fault-tolerant cost.The optimal plan is selected by calculating and ranking fault-tolerant rates.Finally,a case study in Shenzhen,China is provided to verify the reasonability and effectiveness of the method.The results show that the proposed method can help discover and address the‘fault’of vehicle dispatching plans during emergency preparedness and thus improve evacuation capabilities in emergency response.The proposed method can be used to develop evacuation vehicle dispatching planning methods with comprehensive scenario adaptability and a precisely improved capability.
基金supported in part by National Natural Science Foundation of China(Nos.62373188,62003162)the Natural Science Foundation of Jiangsu Province of China(Nos.BK20240182,BK20222012)+2 种基金the Industry-University Research Innovation Foundation for the Chinese Ministry of Education(No.2021ZYA02005)the Aeronautical Science Foundation of China(Nos.20220007052003,20200007018001)the Fundamental Research Funds for the Central Universities,China(Nos.NE2024004,NI2024001)。
文摘To solve the problem of in-flight actuator faults and parameter uncertainties for multiple Unmanned Aerial Vehicles(UAVs),and reduce the communication and computational resource consumption of multiple UAVs,a Fraction-Order(FO)sliding-mode Fault-Tolerant Cooperative Control(FTCC)strategy is proposed for multiple UAVs based on Event-Triggered Communication Mechanism(ET-COM-M)and Event-Triggered Control Mechanism(ET-CON-M).First,by considering the limited communication bandwidth of multiple UAVs in formation,an ET-COM-M is designed to significantly reduce communication times.Then,a distributed observer is skillfully constructed to estimate the reference signals for follower UAVs.Moreover,the adaptive strategy is incorporated into the Radial Basis Function Neural Network(RBFNN)to learn the lumped unknown terms for handling bias actuator faults and parameter uncertainties.Besides,the Nussbaum method is used to deal with the loss-of-effectiveness faults.To further achieve the refined control performance against faults,FO calculus is artfully integrated into the sliding-mode control protocol with ET-CON-M.Finally,Zeno behavior is excluded by rigorous theoretical analysis and Lyapunov stability is proved to show the effectiveness of the designed FTCC strategy.Simulation results show that the designed FTCC strategy with Event-Triggered Mechanism(ETM)can guarantee the safety of multiple UAVs and simultaneously reduce the communication and control frequencies,making the developed control scheme applicable in engineering.
基金supported by National Natural Science Foundation of China[grant number 62173208]Taishan Scholar Project of Shandong Province of China[grant number tsqn202103061]。
文摘This paper is dedicated to solving the problem of adaptive fuzzy fault-tolerant tracking control for a class of time-varying high-order uncertain nonlinear systems.The motivation comes from how to construct a compact set large enough in which the approximation of any unknown continuous function by a fuzzy logic system(FLS)is effective while compensating sensor/actuator faults and external disturbances.The difficulty is to verify the boundedness of closed-loop signals on the constructed compact set and to reduce the number of the variables of the fuzzy membership functions as many as possible.By a new lemma,linear/nonlinear terms are introduced in adaptive laws to dominate unknown residual terms.With adding a power integrator method,a unified fault-tolerant controller is designed to drive the tracking error to converge to a small compact set of the origin within a fixed time,regardless of whether the system suffers from faults and disturbances.Superior to the existing results,in the presence of time-varying factors the scheme of this paper clarifies the logical relationship between the compactness of the approximation and the boundedness of the state variables.Finally,the application of control strategy is demonstrated by numerical/practical examples.
基金supported by the National Natural Science Foundation of China(62333011,62020106003)the Natural Science Foundation of Jiangsu Province of China(BK20222012)+1 种基金the Fundamental Research Funds for the Central Universities(NE2024005)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX24_0594)。
文摘This paper is concerned with adaptive consensus tracking control of nonlinear multi-agent systems with actuator faults and unknown nonidentical control directions under double semi-Markovian switching topologies.Considering the complex working environment and the stability differences in communication links between leaders and followers,a double semi-Markov process is first introduced to describe the random switching of communication topologies in the leader-follower structure.In order to address challenges from the unknown nonidentical control directions and partial loss of effectiveness actuator faults,a completely independent parameter is introduced into the Nussbaum function to overcome the inherent obstacle of mutual cancellation and avoid the rapid growth rate.Considering only the state information of agents is transmitted among the agents,an adaptive distributed fault-tolerant consensus tracking control is proposed based on the double semi-Markovian switching topologies using the designed Nussbaum function.Furthermore,the stability of the closed-loop nonlinear multi-agent systems is analyzed using contradiction argument and Lyapunov theorem,from which the asymptotic consensus tracking in mean square sense can be obtained.A numerical simulation example is provided to verify the effectiveness of the proposed algorithm.
基金supported by the National Natural Science Foundation of China(62403340,62303339)Sichuan Science and Technology Program(2026NSFSC1518)+2 种基金China Postdoctoral Science Foundation(CPSF)(2025T180940,2024M762208)Postdoctoral Fellowship Program of CPSF(GZC20231783)Guangxi Key Laboratory of Brain-Inspired Computing and Intelligent Chips(BCIC-24-K2)。
文摘To address the finite-time tracking control problem for fractional-order nonlinear systems(FONSs) with actuator faults and external disturbance,a novel strategy of the finite-time adaptive fuzzy fault-tolerant controller is presented in this paper by utilizing the finite-time stability theory and fractional-order dynamic surface control scheme combined with backstepping method.A new lemma is developed for analyzing the finite-time stability of FONSs in terms of fractional differential inequality,which modifies some existing results.Fuzzy logic systems are adopted to identify unknown nonlinear characteristics in FONS.In order to compensate for the influence of unknown external disturbance and estimation error for fuzzy logic systems,an auxiliary function is employed to estimate the upper bound of parameters online.Furthermore,a global coordinate transformation is first introduced initially to decouple the fractional-order dynamic system of a specific class of underactuated single-link flexible manipulator systems,thereby transforming it into lower triangular systems.Simulation analyses and experimental results verify the feasibility and effectiveness of finite-time tracking control algorithm.
基金supported in part by the National Natural Science Foundation of China under Grant 52177051in part by the Postgraduate Research and Practice Innovation Program of Jiangsu Province under Grant SJCX25_2046in part by the Key Research Project of Basic Science(Natural Science)in Jiangsu Province under Grant 24KJA470005.
文摘Owing to the multi-degree-of-freedom characteristics and inherent fault-tolerant capacity,six-phase motors have been widely adopted in high-power applications,such as electric vehicle propulsion and aerospace systems.This paper presents the fault-tolerant control strategy of symmetrical six-phase permanent magnet synchronous motor(SSPMSM)under an isolated neutral point topology and proposes a fault diagnosis scheme based on joint diagnosis of multiple variables.First,two mathematical models of SSPMSM and their relationship are established.Subsequently,the current vectors in the torque subspace and harmonic subspace of the two winding sets under fault conditions are analyzed,and the cause of post-fault torque ripple is explained as resulting from controller conflict.In addition,a multivariate fault diagnosis scheme based on voltage threshold in the x-y subspace and current trajectory characteristics in theα-βsubspace is proposed to enhance the diagnostic accuracy.Finally,the feasibility and stability of the proposed control and diagnosis methods are verified by experiments.
基金the National Natural Science Foundation of China NSF of Hubei Province.
文摘The cooperation of different processes may be lost by mistake when a protocol is executed. The protocol cannot be normally operated under this condition. In this paper,the self fault-tolerance of protocols is discussed, and a semanticsbased approach for achieving self fault-tolerance of protocols is presented. Some main characteristics of self fault-tolerance of protocols concerning liveness, nontermination and infinity are also presented. Meanwhile, the sufficient and necessary conditions for achieving self fault-tolerance of protocols are given. Finally, a typical protocol that does not satisfy the self fault-tolerance is investigated, and a new redesign version of this existing protocol using the proposed approach is given.
基金supported by Southern Marine Science and Engineering Guangdong Laboratory Grant No.SML2023SP229。
文摘The cross-domain capabilities of aerial-aquatic vehicles(AAVs)hold significant potential for future airsea integrated combat operations.However,the failure rate of AAVs is higher than that of unmanned systems operating in a single medium.To ensure the reliable and stable completion of tasks by AAVs,this paper proposes a tiltable quadcopter AAV to mitigate the potential issue of rotor failure,which can lead to high-speed spinning or damage during cross-media transitions.Experimental validation demonstrates that this tiltable quadcopter AAV can transform into a dual-rotor or triple-rotor configuration after losing one or two rotors,allowing it to perform cross-domain movements with enhanced stability and maintain task completion.This enhancement significantly improves its fault tolerance and task reliability.
文摘Fault tolerance is essential for reliable and sustainable smart city infrastructure.Interconnected IoT systems must function under frequent faults,limited resources,and complex conditions.Existing research covers various fault-tolerant methods.However,current reviews often lack system-level critique and multidimensional analysis.This study provides a structured review of fault tolerance strategies across layered IoT architectures in smart cities.It evaluates fault detection,containment,and recovery techniques using specific metrics.These include fault visibility,propagation depth,containment score,and energy-resilience trade-offs.The analysis uses comparative tables,architecture-aware discussions,and conceptual plots.It investigates the impact of fault tolerance on decision-making in Supervisory Control And Data Acquisition(SCADA)systems,sensor networks,and real-time controllers.Simulation results and logic-based design support the relationships between evaluation metrics.Findings show a common reliance on redundancy and reactive methods.Many techniques fail to address cross-layer propagation,context-aware adaptation,and silent fault impact on user trust.The study combines these overlooked aspects into a system-level framework.This survey identifies performance bottlenecks and supports the design of adaptive,energy-efficient,and transparent IoT systems.The results contribute to bridging technical reliability with public trust,supporting scalable and responsible smart city development.
基金supported by the National Natural Science Foundation of China(Grant Nos.51991382 and 52277035)the Fundamental Research Funds for the Central Universities(Grant No.2242024K40032).
文摘The field modulation effect has been proposed and investigated in various electric machine topologies.Among them,permanent magnet vernier machines(PMVMs)have attained intensive research due to the high torque density and simple structure.However,the performance of PMVMs in terms of fault tolerance is seldom mentioned.This article proposes a novel dual 3-phase fault-tolerant PMVM with segregated concentric windings.Benefiting from the field modulation effect,the PMVM can generate high torque with low PM flux.The low PM flux also implies small fault currents in the short-circuit case.Therefore,the PMVM exhibits inherent good fault-tolerant capability without sacrificing torque performance.Two independent 3-phase modular winding sets are adopted to improve redundancy.To realize the physical and electrical isolation,each winding set is controlled by a standard 3-phase inverter.The healthy performance and fault tolerance of the proposed machine are evaluated by finite element analysis and verified by experimental tests.The results infer its advantages in healthy conditions and various fault scenarios,including open-circuit,short-circuit,and interturn short-circuit conditions.
基金Supported by the National Key R&D Program of China(2021YFB2011300)the National Natural Science Foundation of China(52275044,52205299)+1 种基金the Zhejiang Provincial Natural Science Foundation of China(Z23E050032)the China Postdoctoral Science Foundation(2022M710304).
文摘The operating environment of the diesel engine air path system is complex and may be affected by external random disturbances.Potentially leading to faults.This paper addresses the fault-tolerant control problem of the diesel engine air path system,assuming that the system may simultaneously be affected by actuator faults and external random disturbances,a disturbance observer-based sliding mode controller is designed.Through the linear matrix inequality technique for solving observer and controller gains,optimal gain matrices can be obtained,eliminating the manual adjustment process of controller parameters and reducing the chattering phenomenon of the sliding mode surface.Finally,the effectiveness of the proposed method is verified through simulation analysis.
基金supported in part by the National Natural Science Foundation of China under Grant 62303144,62020106003,U22A2044in part by the Zhejiang Provincial Natural Science Foundation of China under Grant LQ23F030013.
文摘This paper investigates the issue of fault-tolerant control for swarm systems subject to switched graphs,actuator faults and obstacles.A geometric-based partial differential equation(PDE)framework is proposed to unify collision-free trajectory generation and fault-tolerant control.To deal with the fault-induced force imbalances,the Riemannian metric is proposed to coordinate nominal controllers and the global one.Then,Riemannianbased trajectory length optimization is solved by gradient's dynamic model-heat flow PDE,under which a feasible trajectory satisfying motion constraints is achieved to guide the faulty system.Such virtual control force emerges autonomously through this metric adjustments.Further,the tracking error is rigorously proven to be exponential boundedness.Simulation results confirm the validity of these theoretical findings.
基金supported by Nguyen Tat Thanh University,Ho Chi Minh City,Vietnam,provided with the facilities required to carry out this work.
文摘Hydraulic-electric systems are widely utilized in various applications.However,over time,these systems may encounter random faults such as loose cables,ambient environmental noise,or sensor aging,leading to inaccurate sensor readings.These faults may result in system instability or compromise safety.In this paper,we propose a fault compensation control system to mitigate the effects of sensor faults and ensure system safety.Specifically,we utilize the pressure sensor within the system to implement the control process and evaluate performance based on the piston position.First,we develop a mathematical model to identify optimal parameters for the fault estimation model based on the Lyapunov stability principle.Next,we design an unknown input observer that estimates the state vector and detects pressure sensor faults using a linear matrix inequality optimization algorithm.The estimated pressure faults are incorporated into the fault compensation control system to counteract their effects via a fault residual coefficient.The discrepancy between the feedback state and the estimated state determines this coefficient.We assess the piston position’s performance through pressure control to evaluate the proposed model’s effectiveness.Finally,the system simulation results are analyzed to validate the efficiency of the proposed model.When a pressure sensor fault occurs,the proposed approach effectively minimizes position control errors,enhancing overall system stability.When a pressure sensor fault occurs,the proposed model compensates for the fault to mitigate the impact of pressure problem,thereby enhancing the position control quality of the EHA system.The fault compensation method ensures over 90%system performance,with its effectiveness becoming more evident under pressure sensor faults.
基金supported in part by the National Natural Science Foundation of China under Grants 61991404,62103093 and 62473089the Research Program of the Liaoning Liaohe Laboratory,China under Grant LLL23ZZ-05-01+5 种基金the Key Research and Development Program of Liaoning Province of China under Grant 2023JH26/10200011the 111 Project 2.0 of China under Grant B08015,the National Key Research and Development Program of China under Grant 2022YFB3305905the Xingliao Talent Program of Liaoning Province of China under Grant XLYC2203130the Natural Science Foundation of Liaoning Province of China under Grants 2024JH3/10200012 and 2023-MS-087the Open Research Project of the State Key Laboratory of Industrial Control Technology of China under Grant ICT2024B12the Fundamental Research Funds for the Central Universities of China under Grants N2108003 and N2424004.
文摘The problem of trajectory tracking for a class of differentially driven wheeled mobile robots(WMRs)under partial loss of the effectiveness of the actuated wheels is investigated in this paper.Such actuator faults may cause the loss of strong controllability of the WMR,such that the conventional fault-tolerant control strategies unworkable.In this paper,a new mixed-gain adaption scheme is devised,which is adopted to adapt the gain of a decoupling prescribed performance controller to adaptively compensate for the loss of the effectiveness of the actuators.Different from the existing gain adaption technique which depends on both the barrier functions and their partial derivatives,ours involves only the barrier functions.This yields a lower magnitude of the resulting control signals.Our controller accomplishes trajectory tracking of the WMR with the prescribed rate and accuracy even in the faulty case,and the control design relies on neither the information of the WMR dynamics and the actuator faults nor the tools for function approximation,parameter identification,and fault detection or estimation.The comparative simulation results justify the theoretical findings.
基金supported by National Natural Science Foundation of China under Project 52437003 and 52421004in part by the National Key R&D Program of China under Project 2023YFB3406000in part by Heilongjiang Provincial Natural Science Foundation under Project YQ2022E029.
文摘Permanent-magnet synchronous machines(PMSMs)are widely used in robotics,rail transportation,and electric vehicles owing to their high power density,high efficiency,and high power factor.However,PMSMs often operate in harsh environments,where critical components such as windings and permanent magnets(PMs)are susceptible to failures.These faults can lead to a significant degradation in performance,posing substantial challenges to the reliable operation of PMSMs.This paper presents a comprehensive review of common fault types in PMSMs,along with their corresponding fault diagnosis and fault-tolerant control strategies.The underlying mechanisms of typical faults are systematically analyzed,followed by a detailed comparison of various diagnostic and fault-tolerant control methods to evaluate their respective advantages and limitations.Finally,the review concludes by identifying key research gaps in PMSM fault diagnosis and fault-tolerant control,while proposing potential future directions for advancing this field.
