With the development of cyber-physical systems,system security faces more risks from cyber-attacks.In this work,we study the problem that an external attacker implements covert sensor and actuator attacks with resourc...With the development of cyber-physical systems,system security faces more risks from cyber-attacks.In this work,we study the problem that an external attacker implements covert sensor and actuator attacks with resource constraints(the total resource consumption of the attacks is not greater than a given initial resource of the attacker)to mislead a discrete event system under supervisory control to reach unsafe states.We consider that the attacker can implement two types of attacks:One by modifying the sensor readings observed by a supervisor and the other by enabling the actuator commands disabled by the supervisor.Each attack has its corresponding resource consumption and remains covert.To solve this problem,we first introduce a notion of combined-attackability to determine whether a closedloop system may reach an unsafe state after receiving attacks with resource constraints.We develop an algorithm to construct a corrupted supervisor under attacks,provide a verification method for combined-attackability in polynomial time based on a plant,a corrupted supervisor,and an attacker's initial resource,and propose a corresponding attack synthesis algorithm.The effectiveness of the proposed method is illustrated by an example.展开更多
In this paper, a hybrid neural-genetic fuzzy system is proposed to control the flow and height of water in the reservoirs of water transfer networks. These controls will avoid probable water wastes in the reservoirs a...In this paper, a hybrid neural-genetic fuzzy system is proposed to control the flow and height of water in the reservoirs of water transfer networks. These controls will avoid probable water wastes in the reservoirs and pressure drops in water distribution networks. The proposed approach combines the artificial neural network, genetic algorithm, and fuzzy inference system to improve the performance of the supervisory control and data acquisition stations through a new control philosophy for instruments and control valves in the reservoirs of the water transfer networks. First, a multi-core artificial neural network model, including a multi-layer perceptron and radial based function, is proposed to forecast the daily consumption of the water in a reservoir. A genetic algorithm is proposed to optimize the parameters of the artificial neural networks. Then, the online height of water in the reservoir and the output of artificial neural networks are used as inputs of a fuzzy inference system to estimate the flow rate of the reservoir inlet. Finally, the estimated inlet flow is translated into the input valve position using a transform control unit supported by a nonlinear autoregressive exogenous model. The proposed approach is applied in the Tehran water transfer network. The results of this study show that the usage of the proposed approach significantly reduces the deviation of the reservoir height from the desired levels.展开更多
This paper introduces a kind of Feeder Control Units (FCUs) which treat feeders or main transformers as its objects. Being carefully designed, the FCU can separately meet the requirements such as signals’ acquisition...This paper introduces a kind of Feeder Control Units (FCUs) which treat feeders or main transformers as its objects. Being carefully designed, the FCU can separately meet the requirements such as signals’ acquisition, local control, on-time switchgear interlocking, etc. Equipped with a sort of high-speed serial communicahon interface, the FCUs can be distributively arranged near or into the switchgear, therefore a kind of distributed substation supervisory system can be formed.展开更多
This paper describes a supervisory hierarchical fuzzy controller （SHFC） for regulating pressure in a real-time pilot pressure control system. The input scaling factor tuning of a direct expert controller is made usi...This paper describes a supervisory hierarchical fuzzy controller （SHFC） for regulating pressure in a real-time pilot pressure control system. The input scaling factor tuning of a direct expert controller is made using the error and process input parameters in a closed loop system in order to obtain better controller performance for set-point change and load disturbances. This on-line tuning method reduces operator involvement and enhances the controller performance to a wide operating range. The hierarchical control scheme consists of an intelligent upper level supervisory fuzzy controller and a lower level direct fuzzy controller. The upper level controller provides a mechanism to the main goal of the system and the lower level controller delivers the solutions to a particular situation. The control algorithm for the proposed scheme has been developed and tested using an ARM7 microcontroller-based embedded target board for a nonlinear pressure process having dead time. To demonstrate the effectiveness, the results of the proposed hierarchical controller, fuzzy controller and conventional proportional-integral （PI） controller are analyzed. The results prove that the SHFC performance is better in terms of stability and robustness than the conventional control methods.展开更多
This paper studied a supervisory control system for a hybrid off-highway electric vehicle under the chargesustaining(CS)condition.A new predictive double Q-learning with backup models(PDQL)scheme is proposed to optimi...This paper studied a supervisory control system for a hybrid off-highway electric vehicle under the chargesustaining(CS)condition.A new predictive double Q-learning with backup models(PDQL)scheme is proposed to optimize the engine fuel in real-world driving and improve energy efficiency with a faster and more robust learning process.Unlike the existing“model-free”methods,which solely follow on-policy and off-policy to update knowledge bases(Q-tables),the PDQL is developed with the capability to merge both on-policy and off-policy learning by introducing a backup model(Q-table).Experimental evaluations are conducted based on software-in-the-loop(SiL)and hardware-in-the-loop(HiL)test platforms based on real-time modelling of the studied vehicle.Compared to the standard double Q-learning(SDQL),the PDQL only needs half of the learning iterations to achieve better energy efficiency than the SDQL at the end learning process.In the SiL under 35 rounds of learning,the results show that the PDQL can improve the vehicle energy efficiency by 1.75%higher than SDQL.By implementing the PDQL in HiL under four predefined real-world conditions,the PDQL can robustly save more than 5.03%energy than the SDQL scheme.展开更多
The supervisory control problem for discrete event system(DES) under control involves identifying the supervisor, if one exists, which, when synchronously composed with the DES,results in a system that conforms to the...The supervisory control problem for discrete event system(DES) under control involves identifying the supervisor, if one exists, which, when synchronously composed with the DES,results in a system that conforms to the control specification. In this context, we consider a non-deterministic DES under complete observation and control specification expressed in action-based propositional μ-calculus. The key to our solution is the process of quotienting the control specification against the plan resulting in a new μ-calculus formula such that a model for the formula is the supervisor. Thus the task of control synthesis is reduced a problem of μ-calculus satisfiability. In contrast to the existing μ-calculus quotienting-based techniques that are developed in deterministic setting, our quotienting rules can handle nondeterminism in the plant models. Another distinguishing feature of our technique is that while existing techniques use a separate μ-calculus formula to describe the controllability constraint(that uncontrollable events of plants are never disabled by a supervisor), we absorb this constraint as part of quotienting which allows us to directly capture more general state-dependent controllability constraints. Finally, we develop a tableau-based technique for verifying satisfiability of quotiented formula and model generation. The runtime for the technique is exponential in terms of the size of the plan and the control specification. A better complexity result that is polynomial to plant size and exponential to specification size is obtained when the controllability property is state-independent. A prototype implementation in a tabled logic programming language as well as some experimental results are presented.展开更多
Supervisory control is a very popular paradigm for computer-controlled systems.Knowledge and tracking the control effect of every control operation is crucial to the control tasks.In the paper,we present a message-arr...Supervisory control is a very popular paradigm for computer-controlled systems.Knowledge and tracking the control effect of every control operation is crucial to the control tasks.In the paper,we present a message-array-based mechanism to track control effects in supervisory control software.A novel data type,message array,is designed to efficiently support this tracking mechanism.The operation algorithms,adding algorithm(AA),removing algorithm(RA),and scheduler algorithm(SA)are proposed to operate the tracking messages in message array,which forms the special first input X output(FIXO)strategy of message array.Automatically tracking,recording,and rolling back are the characteristics of our tracking mechanism.We implement this messagearray-based mechanism on the famous human machine interface(HMI)software platform-proficy iFix,and construct experiments to evaluate the performance of the mechanism in various cases.The results show our mechanism can be well satisfied with supervisory control software.展开更多
Due to space availability limitations and high land costs,there is an increasing development of multi-floor manufacturing(MFM)systems in urban and industrial areas.The problem of coordination in a multi-floor manufact...Due to space availability limitations and high land costs,there is an increasing development of multi-floor manufacturing(MFM)systems in urban and industrial areas.The problem of coordination in a multi-floor manufacturing process,in the Ramadge Wonham framework,is introduced.The manufacturing chain of each floor and the elevator system are modeled in the form of finite deterministic automata.The models of the multi-floor manufacturing process are parametric with respect to the number of floors and the number of manufacturing machines on each floor.The coordination desired performance is formulated in the form of desired regular languages in analytic forms.The languages are realized by appropriate supervisors in the form of finite deterministic automata.The models of the supervisors are also parametric with respect to the number of floors and the number of manufacturing machines on each floor.The total control of the coordination of the multi-floor manufacturing process is accomplished via a modular supervisory control architecture.The complexity of the supervisors as well as the complexity of the total modular supervisory architecture are determined in analytic forms with respect to the number of floors and the number of manufacturing machines on each floor.The special case of a two floor manufacturing process is presented as an illustrative example.展开更多
In order to reduce chattering phenomenon of variable structure control, a fuzzy variable structure control method is adopted and applied in the photovoitaic maximum power point tracking （MPPT） control system. Firstl...In order to reduce chattering phenomenon of variable structure control, a fuzzy variable structure control method is adopted and applied in the photovoitaic maximum power point tracking （MPPT） control system. Firstly, the electric features of PV cells and a dynamic model of photovoitaic system with a DGDC buck converter are analysed. Then a hybrid fuzzy variable structure controller is designed. The controller is composed of a fuzzy variable structure control term and a supervisory control term. The former is the main part of the controller and the latter is used to ensure the stability of the system. Finally, the conventional variable structure control method and the fuzzy variable structure control method are applied respectively. The comparing of simulation results shows the superiority of the latter.展开更多
This paper proposes to adopt SCADA and PLC technology for the improvement of the performance of real time signaling&train control systems in metro railways.The main concern of this paper is to minimize the failure...This paper proposes to adopt SCADA and PLC technology for the improvement of the performance of real time signaling&train control systems in metro railways.The main concern of this paper is to minimize the failure in automated metro railways system operator and integrate the information coming from Operational Control Centre(OCC),traction SCADA system,traction power control,and power supply system.This work presents a simulated prototype of an automated metro train system operator that uses PLC and SCADA for the real time monitoring and control of the metro railway systems.Here,SCADA is used for the visualization of an automated process operation and then the whole opera-tion is regulated with the help of PLC.The PLC used in this process is OMRON(NX1P2-9024DT1)and OMRON’s Sysmac studio programming software is used for developing the ladder logic of PLC.The metro railways system has deployed infrastructure based on SCADA from the power supply system,and each station’s traction power control is connected to the OCC remotely which commands all of the stations and has the highest command priority.An alarm is triggered in the event of an emergency or system congestion.This proposed system overcomes the drawbacks of the current centralized automatic train control(CATC)system.This system provides prominent benefits like augmenting services which may enhance a network’s full load capacity and networkflexibility,which help in easy modification in the existing program at any time.展开更多
This paper presents the development of a classical and intelligent control approaches applied to a flexible single-link manipulator robot and compared in terms of input tracking and vibration suppression. Lagrange＇s ...This paper presents the development of a classical and intelligent control approaches applied to a flexible single-link manipulator robot and compared in terms of input tracking and vibration suppression. Lagrange＇s equations and finite elements method are combined to compute dynamic model of a flexible link manipulator with one rigid joint. Next, dynamics are itemized to explain flexible link behavior. Then a fuzzy supervisory controller is developed and introduced in the high level of the closed-loop of the flexible manipulator. A generalized predictive controller is then developed and introduced in the flexible system closed-loop to minimize end-point residual vibrations. Simulation results obtained are compared to a GPC （generalized predictive controller） in terms of end-point vibration suppression, input tracking and disturbance rejection. A conclusion encloses the paper.展开更多
As quantum computing continues to advance,traditional cryptographic methods are increasingly challenged,particularly when it comes to securing critical systems like Supervisory Control andData Acquisition(SCADA)system...As quantum computing continues to advance,traditional cryptographic methods are increasingly challenged,particularly when it comes to securing critical systems like Supervisory Control andData Acquisition(SCADA)systems.These systems are essential for monitoring and controlling industrial operations,making their security paramount.A key threat arises from Shor’s algorithm,a powerful quantum computing tool that can compromise current hash functions,leading to significant concerns about data integrity and confidentiality.To tackle these issues,this article introduces a novel Quantum-Resistant Hash Algorithm(QRHA)known as the Modular Hash Learning Algorithm(MHLA).This algorithm is meticulously crafted to withstand potential quantum attacks by incorporating advanced mathematical and algorithmic techniques,enhancing its overall security framework.Our research delves into the effectiveness ofMHLA in defending against both traditional and quantum-based threats,with a particular emphasis on its resilience to Shor’s algorithm.The findings from our study demonstrate that MHLA significantly enhances the security of SCADA systems in the context of quantum technology.By ensuring that sensitive data remains protected and confidential,MHLA not only fortifies individual systems but also contributes to the broader efforts of safeguarding industrial and infrastructure control systems against future quantumthreats.Our evaluation demonstrates that MHLA improves security by 38%against quantumattack simulations compared to traditional hash functionswhilemaintaining a computational efficiency ofO(m⋅n⋅k+v+n).The algorithm achieved a 98%success rate in detecting data tampering during integrity testing.These findings underline MHLA’s effectiveness in enhancing SCADA system security amidst evolving quantum technologies.This research represents a crucial step toward developing more secure cryptographic systems that can adapt to the rapidly changing technological landscape,ultimately ensuring the reliability and integrity of critical infrastructure in an era where quantum computing poses a growing risk.展开更多
In this paper,a deadlock prevention policy for robotic manufacturing cells with uncontrollable and unobservable events is proposed based on a Petri net formalism.First,a Petri net for the deadlock control of such syst...In this paper,a deadlock prevention policy for robotic manufacturing cells with uncontrollable and unobservable events is proposed based on a Petri net formalism.First,a Petri net for the deadlock control of such systems is defined.Its admissible markings and first-met inadmissible markings(FIMs)are introduced.Next,place invariants are designed via an integer linear program(ILP)to survive all admissible markings and prohibit all FIMs,keeping the underlying system from reaching deadlocks,livelocks,bad markings,and the markings that may evolve into them by firing uncontrollable transitions.ILP also ensures that the obtained deadlock-free supervisor does not observe any unobservable transition.In addition,the supervisor is guaranteed to be admissible and structurally minimal in terms of both control places and added arcs.The condition under which the supervisor is maximally permissive in behavior is given.Finally,experimental results with the proposed method and existing ones are given to show its effectiveness.展开更多
With the wide application of electronic hardware in aircraft such as air-to-ground communication,satellite communication,positioning system and so on,aircraft hardware is facing great secure pressure.Focusing on the s...With the wide application of electronic hardware in aircraft such as air-to-ground communication,satellite communication,positioning system and so on,aircraft hardware is facing great secure pressure.Focusing on the secure problem of aircraft hardware,this paper proposes a supervisory control architecture based on secure System-on-a-Chip(So C)system.The proposed architecture is attack-immune and trustworthy,which can support trusted escrow application and Dynamic Integrity Measurement(DIM)without interference.This architecture is characterized by a Trusted Monitoring System(TMS)hardware isolated from the Main Processor System(MPS),a secure access channel from TMS to the running memory of the MPS,and the channel is unidirectional.Based on this architecture,the DIM program running on TMS is used to measure and call the Lightweight Measurement Agent(LMA)program running on MPS.By this method,the Operating System(OS)kernel,key software and data of the MPS can be dynamically measured without disturbance,which makes it difficult for adversaries to attack through software.Besides,this architecture has been fully verified on FPGA prototype system.Compared with the existing systems,our architecture achieves higher security and is more efficient on DIM,which can fully supervise the running of application and aircraft hardware OS.展开更多
The responses of vehicles to the changes in traffic situations inevitably have delays in observing an event and implementing a control command,which often causes fatal accidents.So far,the methods for handling delays ...The responses of vehicles to the changes in traffic situations inevitably have delays in observing an event and implementing a control command,which often causes fatal accidents.So far,the methods for handling delays are empirical and cannot be mathematically proven.To eliminate the accidents caused by such delays,in this paper,we develop mathematically provable methods to handle these delays.Specifically,we use networked discrete event systems to model the process of driving vehicles and present a supervisory controller for handling delay situations.The method developed in this paper could serve as a new start for modeling and controlling the responsive behaviors of self-driving vehicles in the future.展开更多
The measurement and control of the molten steel level are studied, which affect the quality of strip surface in strip casting. A system of molten steel measurement with a CCD (Charge Coupled Devices) sensor is designe...The measurement and control of the molten steel level are studied, which affect the quality of strip surface in strip casting. A system of molten steel measurement with a CCD (Charge Coupled Devices) sensor is designed, real-time measured data are given and its precision is analyzed. The level fluctuation model is derived, and an adaptive fuzzy-PID controller with supervisory control (AFPS) is proposed. The stability of the system is proved using Lyapunov theorem, and the simulation results are given when the model, the casting speed and the roll gap change. It is suggested that this kind of coupled nonlinear and time varying system is stable and robust using the designed AFPS controller.展开更多
This work developed the modeling and supervisory control for gas turbine. A CTPN （continuous timed Petri Net） model of a gas turbine, using a first linear order approximation for every state of the Brayton cycle is ...This work developed the modeling and supervisory control for gas turbine. A CTPN （continuous timed Petri Net） model of a gas turbine, using a first linear order approximation for every state of the Brayton cycle is obtained. The Brayton cycle rules the functioning of a gas turbine, and it is composed by four states： compression, combustion, expansion and cooling. The principle of the gas turbine is developed by the Brayton cycle, a thermodynamic process which intervenes in the gas turbine components. The steady-state behavior of the gas turbine has been widely investigated in engineering area. Moreover, the dynamic behavior has been studied using non-linear models of its components, leading to complicated mathematical representations. The methodology of the current work begins with a simplification of the dynamical relations in every state （excepting the cooling phase） of the Brayton cycle. Temperature and pressure are modeled as first order linear systems, therefore, every system is translated into a CTPN. Furthermore, to guarantee a safety operation, an SC （supervisory controller） is designed to ensure the combustion chamber temperature is lower than 1,000 ℃. Although the model presented is extremely simplified, it will be used as a starting point to develop more complex models.展开更多
Intelligent distribution automation system （IDAS） was developed based on distribution automation system that was installed in all distribution offices of Korea. IDAS was designed the combined system with the functio...Intelligent distribution automation system （IDAS） was developed based on distribution automation system that was installed in all distribution offices of Korea. IDAS was designed the combined system with the function of supervisory control and data acquisition （SCADA） and distribution automation system （DAS） for network operation from substation to high voltage customer, and it has been installed in Vietnam, China and Indonesia. This paper explains the project scope, system configuration, and the function of each sy stem.展开更多
Concurrency is a common feature in most industrial systems,where several components can execute different actions simultaneously.In this paper,we first introduce a new feasible nonblocking concurrent supervisory contr...Concurrency is a common feature in most industrial systems,where several components can execute different actions simultaneously.In this paper,we first introduce a new feasible nonblocking concurrent supervisory control map for a concurrent system,and subsequently,new concepts of concurrent controllability and concurrent observability.Then we present a sufficient and necessary condition for the existence of a feasible nonblocking concurrent supervisory controlmap to achieve a given concurrent language.After introducing a new concept of prefix-closed concurrent normality,we show that the supremal concurrently controllable and prefix-closed concurrently normal sublanguages exist and are computable.Our emphasis here is not to address the computational efficiency of solving concurrent supervisory control problems,which is still a technical challenge,but to show that the commonly used Ramadge–Wonham asynchronous control is simply a special case of our proposed concurrent control framework by providing an insightful treatment on compound events.展开更多
Cyber threats are serious concerns for power systems.For example,hackers may attack power control systems via interconnected enterprise networks.This paper proposes a risk assessment framework to enhance the resilienc...Cyber threats are serious concerns for power systems.For example,hackers may attack power control systems via interconnected enterprise networks.This paper proposes a risk assessment framework to enhance the resilience of power systems against cyber attacks.The duality element relative fuzzy evaluation method is employed to evaluate identified security vulnerabilities within cyber systems of power systems quantitatively.The attack graph is used to identify possible intrusion scenarios that exploit multiple vulnerabilities.An intrusion response system(IRS)is developed to monitor the impact of intrusion scenarios on power system dynamics in real time.IRS calculates the conditional Lyapunov exponents(CLEs)on line based on the phasor measurement unit data.Power system stability is predicted through the values of CLEs.Control actions based on CLEs will be suggested if power system instability is likely to happen.A generic wind farm control system is used for case study.The effectiveness of IRS is illustrated with the IEEE 39 bus system model.展开更多
基金partially supported by the Science Technology Development Fund,Macao Special Administrative Region(0029/2023/RIA1)the National Research Foundation Singapore under its AI Singapore Programme(AISG2-GC-2023-007)
文摘With the development of cyber-physical systems,system security faces more risks from cyber-attacks.In this work,we study the problem that an external attacker implements covert sensor and actuator attacks with resource constraints(the total resource consumption of the attacks is not greater than a given initial resource of the attacker)to mislead a discrete event system under supervisory control to reach unsafe states.We consider that the attacker can implement two types of attacks:One by modifying the sensor readings observed by a supervisor and the other by enabling the actuator commands disabled by the supervisor.Each attack has its corresponding resource consumption and remains covert.To solve this problem,we first introduce a notion of combined-attackability to determine whether a closedloop system may reach an unsafe state after receiving attacks with resource constraints.We develop an algorithm to construct a corrupted supervisor under attacks,provide a verification method for combined-attackability in polynomial time based on a plant,a corrupted supervisor,and an attacker's initial resource,and propose a corresponding attack synthesis algorithm.The effectiveness of the proposed method is illustrated by an example.
文摘In this paper, a hybrid neural-genetic fuzzy system is proposed to control the flow and height of water in the reservoirs of water transfer networks. These controls will avoid probable water wastes in the reservoirs and pressure drops in water distribution networks. The proposed approach combines the artificial neural network, genetic algorithm, and fuzzy inference system to improve the performance of the supervisory control and data acquisition stations through a new control philosophy for instruments and control valves in the reservoirs of the water transfer networks. First, a multi-core artificial neural network model, including a multi-layer perceptron and radial based function, is proposed to forecast the daily consumption of the water in a reservoir. A genetic algorithm is proposed to optimize the parameters of the artificial neural networks. Then, the online height of water in the reservoir and the output of artificial neural networks are used as inputs of a fuzzy inference system to estimate the flow rate of the reservoir inlet. Finally, the estimated inlet flow is translated into the input valve position using a transform control unit supported by a nonlinear autoregressive exogenous model. The proposed approach is applied in the Tehran water transfer network. The results of this study show that the usage of the proposed approach significantly reduces the deviation of the reservoir height from the desired levels.
文摘This paper introduces a kind of Feeder Control Units (FCUs) which treat feeders or main transformers as its objects. Being carefully designed, the FCU can separately meet the requirements such as signals’ acquisition, local control, on-time switchgear interlocking, etc. Equipped with a sort of high-speed serial communicahon interface, the FCUs can be distributively arranged near or into the switchgear, therefore a kind of distributed substation supervisory system can be formed.
文摘This paper describes a supervisory hierarchical fuzzy controller （SHFC） for regulating pressure in a real-time pilot pressure control system. The input scaling factor tuning of a direct expert controller is made using the error and process input parameters in a closed loop system in order to obtain better controller performance for set-point change and load disturbances. This on-line tuning method reduces operator involvement and enhances the controller performance to a wide operating range. The hierarchical control scheme consists of an intelligent upper level supervisory fuzzy controller and a lower level direct fuzzy controller. The upper level controller provides a mechanism to the main goal of the system and the lower level controller delivers the solutions to a particular situation. The control algorithm for the proposed scheme has been developed and tested using an ARM7 microcontroller-based embedded target board for a nonlinear pressure process having dead time. To demonstrate the effectiveness, the results of the proposed hierarchical controller, fuzzy controller and conventional proportional-integral （PI） controller are analyzed. The results prove that the SHFC performance is better in terms of stability and robustness than the conventional control methods.
基金Project(KF2029)supported by the State Key Laboratory of Automotive Safety and Energy(Tsinghua University),ChinaProject(102253)supported partially by the Innovate UK。
文摘This paper studied a supervisory control system for a hybrid off-highway electric vehicle under the chargesustaining(CS)condition.A new predictive double Q-learning with backup models(PDQL)scheme is proposed to optimize the engine fuel in real-world driving and improve energy efficiency with a faster and more robust learning process.Unlike the existing“model-free”methods,which solely follow on-policy and off-policy to update knowledge bases(Q-tables),the PDQL is developed with the capability to merge both on-policy and off-policy learning by introducing a backup model(Q-table).Experimental evaluations are conducted based on software-in-the-loop(SiL)and hardware-in-the-loop(HiL)test platforms based on real-time modelling of the studied vehicle.Compared to the standard double Q-learning(SDQL),the PDQL only needs half of the learning iterations to achieve better energy efficiency than the SDQL at the end learning process.In the SiL under 35 rounds of learning,the results show that the PDQL can improve the vehicle energy efficiency by 1.75%higher than SDQL.By implementing the PDQL in HiL under four predefined real-world conditions,the PDQL can robustly save more than 5.03%energy than the SDQL scheme.
基金supported in part by the National Sci-ence Foundation (NSF-ECCS-1509420, NSF-CSSI-2004766)。
文摘The supervisory control problem for discrete event system(DES) under control involves identifying the supervisor, if one exists, which, when synchronously composed with the DES,results in a system that conforms to the control specification. In this context, we consider a non-deterministic DES under complete observation and control specification expressed in action-based propositional μ-calculus. The key to our solution is the process of quotienting the control specification against the plan resulting in a new μ-calculus formula such that a model for the formula is the supervisor. Thus the task of control synthesis is reduced a problem of μ-calculus satisfiability. In contrast to the existing μ-calculus quotienting-based techniques that are developed in deterministic setting, our quotienting rules can handle nondeterminism in the plant models. Another distinguishing feature of our technique is that while existing techniques use a separate μ-calculus formula to describe the controllability constraint(that uncontrollable events of plants are never disabled by a supervisor), we absorb this constraint as part of quotienting which allows us to directly capture more general state-dependent controllability constraints. Finally, we develop a tableau-based technique for verifying satisfiability of quotiented formula and model generation. The runtime for the technique is exponential in terms of the size of the plan and the control specification. A better complexity result that is polynomial to plant size and exponential to specification size is obtained when the controllability property is state-independent. A prototype implementation in a tabled logic programming language as well as some experimental results are presented.
文摘Supervisory control is a very popular paradigm for computer-controlled systems.Knowledge and tracking the control effect of every control operation is crucial to the control tasks.In the paper,we present a message-array-based mechanism to track control effects in supervisory control software.A novel data type,message array,is designed to efficiently support this tracking mechanism.The operation algorithms,adding algorithm(AA),removing algorithm(RA),and scheduler algorithm(SA)are proposed to operate the tracking messages in message array,which forms the special first input X output(FIXO)strategy of message array.Automatically tracking,recording,and rolling back are the characteristics of our tracking mechanism.We implement this messagearray-based mechanism on the famous human machine interface(HMI)software platform-proficy iFix,and construct experiments to evaluate the performance of the mechanism in various cases.The results show our mechanism can be well satisfied with supervisory control software.
基金Open access funding provided by HEAL-Link Greece.
文摘Due to space availability limitations and high land costs,there is an increasing development of multi-floor manufacturing(MFM)systems in urban and industrial areas.The problem of coordination in a multi-floor manufacturing process,in the Ramadge Wonham framework,is introduced.The manufacturing chain of each floor and the elevator system are modeled in the form of finite deterministic automata.The models of the multi-floor manufacturing process are parametric with respect to the number of floors and the number of manufacturing machines on each floor.The coordination desired performance is formulated in the form of desired regular languages in analytic forms.The languages are realized by appropriate supervisors in the form of finite deterministic automata.The models of the supervisors are also parametric with respect to the number of floors and the number of manufacturing machines on each floor.The total control of the coordination of the multi-floor manufacturing process is accomplished via a modular supervisory control architecture.The complexity of the supervisors as well as the complexity of the total modular supervisory architecture are determined in analytic forms with respect to the number of floors and the number of manufacturing machines on each floor.The special case of a two floor manufacturing process is presented as an illustrative example.
基金Supported by"863"National Hi-tech Project of China(No.2003AA517020)
文摘In order to reduce chattering phenomenon of variable structure control, a fuzzy variable structure control method is adopted and applied in the photovoitaic maximum power point tracking （MPPT） control system. Firstly, the electric features of PV cells and a dynamic model of photovoitaic system with a DGDC buck converter are analysed. Then a hybrid fuzzy variable structure controller is designed. The controller is composed of a fuzzy variable structure control term and a supervisory control term. The former is the main part of the controller and the latter is used to ensure the stability of the system. Finally, the conventional variable structure control method and the fuzzy variable structure control method are applied respectively. The comparing of simulation results shows the superiority of the latter.
文摘This paper proposes to adopt SCADA and PLC technology for the improvement of the performance of real time signaling&train control systems in metro railways.The main concern of this paper is to minimize the failure in automated metro railways system operator and integrate the information coming from Operational Control Centre(OCC),traction SCADA system,traction power control,and power supply system.This work presents a simulated prototype of an automated metro train system operator that uses PLC and SCADA for the real time monitoring and control of the metro railway systems.Here,SCADA is used for the visualization of an automated process operation and then the whole opera-tion is regulated with the help of PLC.The PLC used in this process is OMRON(NX1P2-9024DT1)and OMRON’s Sysmac studio programming software is used for developing the ladder logic of PLC.The metro railways system has deployed infrastructure based on SCADA from the power supply system,and each station’s traction power control is connected to the OCC remotely which commands all of the stations and has the highest command priority.An alarm is triggered in the event of an emergency or system congestion.This proposed system overcomes the drawbacks of the current centralized automatic train control(CATC)system.This system provides prominent benefits like augmenting services which may enhance a network’s full load capacity and networkflexibility,which help in easy modification in the existing program at any time.
文摘This paper presents the development of a classical and intelligent control approaches applied to a flexible single-link manipulator robot and compared in terms of input tracking and vibration suppression. Lagrange＇s equations and finite elements method are combined to compute dynamic model of a flexible link manipulator with one rigid joint. Next, dynamics are itemized to explain flexible link behavior. Then a fuzzy supervisory controller is developed and introduced in the high level of the closed-loop of the flexible manipulator. A generalized predictive controller is then developed and introduced in the flexible system closed-loop to minimize end-point residual vibrations. Simulation results obtained are compared to a GPC （generalized predictive controller） in terms of end-point vibration suppression, input tracking and disturbance rejection. A conclusion encloses the paper.
基金Princess Nourah bint Abdulrahman University Researchers Supporting Project number(PNURSP2025R343),Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabiathe Deanship of Scientific Research at Northern Border University,Arar,Saudi Arabia for funding this research work through the project number NBU-FFR-2025-1092-10.
文摘As quantum computing continues to advance,traditional cryptographic methods are increasingly challenged,particularly when it comes to securing critical systems like Supervisory Control andData Acquisition(SCADA)systems.These systems are essential for monitoring and controlling industrial operations,making their security paramount.A key threat arises from Shor’s algorithm,a powerful quantum computing tool that can compromise current hash functions,leading to significant concerns about data integrity and confidentiality.To tackle these issues,this article introduces a novel Quantum-Resistant Hash Algorithm(QRHA)known as the Modular Hash Learning Algorithm(MHLA).This algorithm is meticulously crafted to withstand potential quantum attacks by incorporating advanced mathematical and algorithmic techniques,enhancing its overall security framework.Our research delves into the effectiveness ofMHLA in defending against both traditional and quantum-based threats,with a particular emphasis on its resilience to Shor’s algorithm.The findings from our study demonstrate that MHLA significantly enhances the security of SCADA systems in the context of quantum technology.By ensuring that sensitive data remains protected and confidential,MHLA not only fortifies individual systems but also contributes to the broader efforts of safeguarding industrial and infrastructure control systems against future quantumthreats.Our evaluation demonstrates that MHLA improves security by 38%against quantumattack simulations compared to traditional hash functionswhilemaintaining a computational efficiency ofO(m⋅n⋅k+v+n).The algorithm achieved a 98%success rate in detecting data tampering during integrity testing.These findings underline MHLA’s effectiveness in enhancing SCADA system security amidst evolving quantum technologies.This research represents a crucial step toward developing more secure cryptographic systems that can adapt to the rapidly changing technological landscape,ultimately ensuring the reliability and integrity of critical infrastructure in an era where quantum computing poses a growing risk.
基金supported by the National Natural Science Foundation of China(61773206)the Natural Science Foundation of Jiangsu Province of China(BK20170131)+1 种基金Jiangsu Overseas Visiting Scholar Program for University Prominent Young&Middle-aged Teachers and Presidents(2019-19)the Deanship of Scientific Research(DSR)at King Abdulaziz University(RG-20-135-38)。
文摘In this paper,a deadlock prevention policy for robotic manufacturing cells with uncontrollable and unobservable events is proposed based on a Petri net formalism.First,a Petri net for the deadlock control of such systems is defined.Its admissible markings and first-met inadmissible markings(FIMs)are introduced.Next,place invariants are designed via an integer linear program(ILP)to survive all admissible markings and prohibit all FIMs,keeping the underlying system from reaching deadlocks,livelocks,bad markings,and the markings that may evolve into them by firing uncontrollable transitions.ILP also ensures that the obtained deadlock-free supervisor does not observe any unobservable transition.In addition,the supervisor is guaranteed to be admissible and structurally minimal in terms of both control places and added arcs.The condition under which the supervisor is maximally permissive in behavior is given.Finally,experimental results with the proposed method and existing ones are given to show its effectiveness.
基金supported by the National Key Research and Development Program of China(No.2017YFB0802502)by the Aeronautical Science Foundation(No.2017ZC51038)+4 种基金by the National Natural Science Foundation of China(Nos.62002006,61702028,61672083,61370190,61772538,61532021,61472429,and 61402029)by the Foundation of Science and Technology on Information Assurance Laboratory(No.1421120305162112006)by the National Cryptography Development Fund(No.MMJJ20170106)by the Defense Industrial Technology Development Program(No.JCKY2016204A102)by the Liaoning Collaboration Innovation Center For CSLE,China。
文摘With the wide application of electronic hardware in aircraft such as air-to-ground communication,satellite communication,positioning system and so on,aircraft hardware is facing great secure pressure.Focusing on the secure problem of aircraft hardware,this paper proposes a supervisory control architecture based on secure System-on-a-Chip(So C)system.The proposed architecture is attack-immune and trustworthy,which can support trusted escrow application and Dynamic Integrity Measurement(DIM)without interference.This architecture is characterized by a Trusted Monitoring System(TMS)hardware isolated from the Main Processor System(MPS),a secure access channel from TMS to the running memory of the MPS,and the channel is unidirectional.Based on this architecture,the DIM program running on TMS is used to measure and call the Lightweight Measurement Agent(LMA)program running on MPS.By this method,the Operating System(OS)kernel,key software and data of the MPS can be dynamically measured without disturbance,which makes it difficult for adversaries to attack through software.Besides,this architecture has been fully verified on FPGA prototype system.Compared with the existing systems,our architecture achieves higher security and is more efficient on DIM,which can fully supervise the running of application and aircraft hardware OS.
文摘The responses of vehicles to the changes in traffic situations inevitably have delays in observing an event and implementing a control command,which often causes fatal accidents.So far,the methods for handling delays are empirical and cannot be mathematically proven.To eliminate the accidents caused by such delays,in this paper,we develop mathematically provable methods to handle these delays.Specifically,we use networked discrete event systems to model the process of driving vehicles and present a supervisory controller for handling delay situations.The method developed in this paper could serve as a new start for modeling and controlling the responsive behaviors of self-driving vehicles in the future.
文摘The measurement and control of the molten steel level are studied, which affect the quality of strip surface in strip casting. A system of molten steel measurement with a CCD (Charge Coupled Devices) sensor is designed, real-time measured data are given and its precision is analyzed. The level fluctuation model is derived, and an adaptive fuzzy-PID controller with supervisory control (AFPS) is proposed. The stability of the system is proved using Lyapunov theorem, and the simulation results are given when the model, the casting speed and the roll gap change. It is suggested that this kind of coupled nonlinear and time varying system is stable and robust using the designed AFPS controller.
文摘This work developed the modeling and supervisory control for gas turbine. A CTPN （continuous timed Petri Net） model of a gas turbine, using a first linear order approximation for every state of the Brayton cycle is obtained. The Brayton cycle rules the functioning of a gas turbine, and it is composed by four states： compression, combustion, expansion and cooling. The principle of the gas turbine is developed by the Brayton cycle, a thermodynamic process which intervenes in the gas turbine components. The steady-state behavior of the gas turbine has been widely investigated in engineering area. Moreover, the dynamic behavior has been studied using non-linear models of its components, leading to complicated mathematical representations. The methodology of the current work begins with a simplification of the dynamical relations in every state （excepting the cooling phase） of the Brayton cycle. Temperature and pressure are modeled as first order linear systems, therefore, every system is translated into a CTPN. Furthermore, to guarantee a safety operation, an SC （supervisory controller） is designed to ensure the combustion chamber temperature is lower than 1,000 ℃. Although the model presented is extremely simplified, it will be used as a starting point to develop more complex models.
文摘Intelligent distribution automation system （IDAS） was developed based on distribution automation system that was installed in all distribution offices of Korea. IDAS was designed the combined system with the function of supervisory control and data acquisition （SCADA） and distribution automation system （DAS） for network operation from substation to high voltage customer, and it has been installed in Vietnam, China and Indonesia. This paper explains the project scope, system configuration, and the function of each sy stem.
基金The support from Singapore Ministry of Education Tier 1 Academic Research[grant number M4011221.040 RG84/13]is gratefully acknowledged.
文摘Concurrency is a common feature in most industrial systems,where several components can execute different actions simultaneously.In this paper,we first introduce a new feasible nonblocking concurrent supervisory control map for a concurrent system,and subsequently,new concepts of concurrent controllability and concurrent observability.Then we present a sufficient and necessary condition for the existence of a feasible nonblocking concurrent supervisory controlmap to achieve a given concurrent language.After introducing a new concept of prefix-closed concurrent normality,we show that the supremal concurrently controllable and prefix-closed concurrently normal sublanguages exist and are computable.Our emphasis here is not to address the computational efficiency of solving concurrent supervisory control problems,which is still a technical challenge,but to show that the commonly used Ramadge–Wonham asynchronous control is simply a special case of our proposed concurrent control framework by providing an insightful treatment on compound events.
文摘Cyber threats are serious concerns for power systems.For example,hackers may attack power control systems via interconnected enterprise networks.This paper proposes a risk assessment framework to enhance the resilience of power systems against cyber attacks.The duality element relative fuzzy evaluation method is employed to evaluate identified security vulnerabilities within cyber systems of power systems quantitatively.The attack graph is used to identify possible intrusion scenarios that exploit multiple vulnerabilities.An intrusion response system(IRS)is developed to monitor the impact of intrusion scenarios on power system dynamics in real time.IRS calculates the conditional Lyapunov exponents(CLEs)on line based on the phasor measurement unit data.Power system stability is predicted through the values of CLEs.Control actions based on CLEs will be suggested if power system instability is likely to happen.A generic wind farm control system is used for case study.The effectiveness of IRS is illustrated with the IEEE 39 bus system model.
