This paper investigates the visual servoing robust stabilization of nonholonomic mobile robots. The calibration of visual parameters is not only complicated, but also needs great consumption of calculated time so that...This paper investigates the visual servoing robust stabilization of nonholonomic mobile robots. The calibration of visual parameters is not only complicated, but also needs great consumption of calculated time so that the accurate calibration is impossible in some situations for high requirement of real timing. Hence, it is interesting and important to consider the design of stabilizing controllers for nonholonomic kinematic systems with uncalibrated visual parameters. A novel uncertain model of these nonholonomic kinematic systems is proposed. Based on this model, a stabilizing controller is discussed by using dynamic feedback and two-step techniques. The proposed robust controller makes the mobile robot image pose and the orientation converge to the desired configuration despite the lack of depth information and the lack of precise visual parameters. The stability of the closed loop system is rigorously proved. The simulation is given to show the effectiveness of the presented controllers.展开更多
Objective:To investigate the impact of precise nursing care based on dynamic nursing quality feedback model on the postoperative recovery of elderly patients undergoing radical resection for colon cancer,with a partic...Objective:To investigate the impact of precise nursing care based on dynamic nursing quality feedback model on the postoperative recovery of elderly patients undergoing radical resection for colon cancer,with a particular focus on its effects on psychological flexibility.Methods:Medical records of 124 elderly patients undergoing radical resection for colon cancer at The First Affiliated Hospital of Baotou Medical College between January 2021 and May 2024 were retrospectively analyzed in this study.Based on the received nursing interventions,the patients were divided into a control group(standard nursing care)and an observation group(precise nursing care based on a dynamic nursing quality feedback model).Results:The observation group exhibited significantly higher levels of hemoglobin,prealbumin,and albumin compared to the control group.Additionally,the observation group had lower scores in somatization,interpersonal sensitivity,depression,anxiety,obsessions-compulsions,hostility,phobic anxiety,psychoticism,and paranoid ideation.The observation group also demonstrated higher scores in active coping,self-efficacy,and the management of emotions,life,and symptoms.Improvements were also observed in nursing quality,perioperative intervention,satisfaction with rehabilitation guidance,and awareness of regular reexaminations,diet intervention,and complication prevention(all with P<0.05).Conclusion:Precise nursing based on a dynamic nursing quality feedback model can improve nutritional status and medical coping style,reduce psychological issues,and enhance self-management abilities in elderly patients following radical resection of colon cancer.Additionally,it increases nursing satisfaction and raises awareness regarding the importance of regular reexaminations and complication prevention.展开更多
An adaptive dynamic load balancing algorithm based on QoS is proposed to improve the performance of load balancing in distributed file system,combining the advantages of a variety of load balancing algorithms.The new ...An adaptive dynamic load balancing algorithm based on QoS is proposed to improve the performance of load balancing in distributed file system,combining the advantages of a variety of load balancing algorithms.The new algorithm uses a tuple containing the number of files and the total file size as the QoS measure for the requested task.The master node sets a threshold for the requested task based on the QoS to filter storage nodes that meet the requirements of the task.In order to guarantee the reliability of the new algorithm,we consider the impact of CPU utilization,memory usage,disk IO occupancy rate,network bandwidth usage and hard disk usage on load balancing performance when calculating the real-time load balancing of storage nodes.The heterogeneity of the network is considered when the master node schedule task assignments to ensure the fairness of the algorithm.The comprehensive evaluation value is determined based the performance load ratio,which is calculated from the real-time load value of the storage node and a performance value after normalization.The master node assigns tasks to the storage node with the highest comprehensive evaluation value.The storage nodes provide adaptive feedback based on changes in the degree of connectivity,rather than periodic update of the load information.The actual distributed file system environment is set up on the server cluster,the performance of the new algorithm is tested through a contrast experiment.The experimental results show that the new algorithm can effectively reduce the average response time of the system,improve throughput,and enable the system load to reach a good balance.展开更多
Current research on pilot-operated relief valve stability is primarily conducted from the perspective of system dynamics or stability criteria,and most of the existing conclusions focus on the spool shape,damping hole...Current research on pilot-operated relief valve stability is primarily conducted from the perspective of system dynamics or stability criteria,and most of the existing conclusions focus on the spool shape,damping hole size,and pulsation frequency of the pump.However,the essential factors pertaining to the unstable vibration of relief valves remain ambiguous.In this study,the dynamic behavior of a pilot-operated relief valve is investigated using the frequency-domain method.The result suggests that the dynamic pressure feedback orifice is vital to the dynamic characteristics of the valve.A large orifice has a low flow resistance.In this case,the fluid in the main spring chamber flows freely,which is not conducive to the stability of the relief valve.However,a small orifice may create significant flow resistance,thus restricting fluid flow.In this case,the oil inside the main valve spring chamber is equivalent to a high-stiffness liquid spring.The main mass-spring vibration system has a natural frequency that differs significantly from the operating frequency of the relief valve,which is conducive to the stability of the relief valve.Good agreement is obtained between the theoretical analysis and experiments.The results indicate that designing a dynamic pressure feedback orifice of an appropriate size is beneficial to improving the stability of hydraulic pilot-operated relief valves.In addition,the dynamic pressure feedback orifice reduces the response speed of the relief valve.This study comprehensively considers the stability,rapidity,and immunity of relief valves and expands current investigations into the dynamic characteristics of relief valves from the perspective of classical control theory,thus revealing the importance of different parameters.展开更多
The problem of the quantized dynamic output feedback controller design for networked control systems is mainly discussed. By using the quantized information of the system measurement output and the control input, a no...The problem of the quantized dynamic output feedback controller design for networked control systems is mainly discussed. By using the quantized information of the system measurement output and the control input, a novel networked control system model is described. This model includes many networkinduced features, such as multi-rate sampled-data, quantized signal, time-varying delay and packet dropout. By constructing suitable Lyapunov-Krasovskii functional, a less conservative stabilization criterion is established in terms of linear matrix inequalities. The quantized control strategy involves the updating values of the quantizer parameters μi（i = 1, 2）（μi take on countable sets of values which dependent on the information of the system measurement outputs and the control inputs）. Furthermore, a numerical example is given to illustrate the effectiveness of the proposed method.展开更多
This paper presents a novel fixed-time stabilization control(FSC)method for a class of strict-feedback nonlinear systems involving unmodelled system dynamics.The key feature of the proposed method is the design of two...This paper presents a novel fixed-time stabilization control(FSC)method for a class of strict-feedback nonlinear systems involving unmodelled system dynamics.The key feature of the proposed method is the design of two dynamic parameters.Specifically,a set of auxiliary variables is first introduced through state transformation.These variables combine the original system states and the two introduced dynamic parameters,facilitating the closed-loop system stability analyses.Then,the two dynamic parameters are delicately designed by utilizing the Lyapunov method,ensuring that all the closed-loop system states are globally fixed-time stable.Compared with existing results,the“explosion of complexity”problem of backstepping control is avoided.Moreover,the two designed dynamic parameters are dependent on system states rather than a time-varying function,thus the proposed controller is still valid beyond the given fixedtime convergence instant.The effectiveness of the proposed method is demonstrated through two practical systems.展开更多
This paper investigates the system security problem of cyber-physical systems(CPSs),which is not only more practical but also more signi cant to deal with than the detecting faults problem.The purpose of this paper is...This paper investigates the system security problem of cyber-physical systems(CPSs),which is not only more practical but also more signi cant to deal with than the detecting faults problem.The purpose of this paper is to nd an optimal attack strategy that maximizes the output error of the attacked system with low energy consumption.Based on a general model of linear time-invariant systems and a key technical lemma,a new optimal attack strategy for the meticulously designed false data injection attack is constructed.It is worth mentioning that compared with the existing model-based attack strategies,the designed one is more general and the corresponding attack strategy is more easily implemented when system states and external input are inaccessible.Key to overcoming the inaccessible information,a dynamic observer in the form of Luenberger is constructed.Finally,a networked magnetic levitation steel ball movement system is applied to illustrate the e ectiveness of the proposed scheme.展开更多
This paper deals with the problems of bifurcation suppression and bifurcation suppression with stability of nonlinear systems. Necessary conditions and sufficient conditions for bifurcation suppression via dynamic out...This paper deals with the problems of bifurcation suppression and bifurcation suppression with stability of nonlinear systems. Necessary conditions and sufficient conditions for bifurcation suppression via dynamic output feedback are presented; Sufficient conditions for bifurcation suppression with stability via dynamic output feedback are obtained. As an application, a dynamic compensator,which guarantees that the bifurcation point of rotating stall in axial flow compressors is stably suppressed, is constructed.展开更多
This paper deals with the dynamic output feedback stabilization problem of deterministic finite automata(DFA).The static form of this problem is defined and solved in previous studies via a set of equivalent condition...This paper deals with the dynamic output feedback stabilization problem of deterministic finite automata(DFA).The static form of this problem is defined and solved in previous studies via a set of equivalent conditions.In this paper,the dynamic output feedback(DOF)stabilization of DFAs is defined in which the controller is supposed to be another DFA.The DFA controller will be designed to stabilize the equilibrium point of the main DFA through a set of proposed equivalent conditions.It has been proven that the design problem of DOF stabilization is more feasible than the static output feedback(SOF)stabilization.Three simulation examples are provided to illustrate the results of this paper in more details.The first example considers an instance DFA and develops SOF and DOF controllers for it.The example explains the concepts of the DOF controller and how it will be implemented in the closed-loop DFA.In the second example,a special DFA is provided in which the DOF stabilization is feasible,whereas the SOF stabilization is not.The final example compares the feasibility performance of the SOF and DOF stabilizations through applying them to one hundred random-generated DFAs.The results reveal the superiority of the DOF stabilization.展开更多
This paper investigates the system security problem of cyber-physical systems(CPSs),which is not only more practical but also more significant to deal with than the detecting faults problem.The purpose of this paper i...This paper investigates the system security problem of cyber-physical systems(CPSs),which is not only more practical but also more significant to deal with than the detecting faults problem.The purpose of this paper is to find an optimal attack strat-egy that maximizes the output error of the attacked system with low energy consumption.Based on a general model of linear time-invariant systems and a key technical lemma,a new optimal attack strategy for the meticulously designed false data injection attack is constructed.It is worth mentioning that compared with the existing model-based attack strategies,the designed one is more general and the corresponding attack strategy is more easily implemented when system states and external input are inaccessible.Key to overcom-ing the inaccessible information,a dynamic observer in the form of Luenberger is constructed.Finally,a networked magnetic levitation steel ball movement system is applied to illustrate the effectiveness of the proposed scheme.展开更多
The paper considers the problem of determining the position of each handle as the bench dragon coils along the spiral.First,the quantitative searching range of the corresponding polar an-gle of the handle is given acc...The paper considers the problem of determining the position of each handle as the bench dragon coils along the spiral.First,the quantitative searching range of the corresponding polar an-gle of the handle is given according to the traveling path characteristics of each handle coiled in,offering the initial value for the proposed algorithm.Then,a dynamical feedback algorithm for calculating the position of the latter handle is proposed,which avoids the multi-solution problem of solving nonlinear equations.Furthermore,to promote the computational efficiency,the design of iterative parameters based on varying polar angles is discussed.In the simulation environment,the effectiveness of the proposed dynamical feedback algorithm is illustrated.展开更多
The quality of the existing building energy-saving renovation market determines the inherent inevitability of incentive,while unique requirements for the incentive should be satisfied by stage characteristics and indi...The quality of the existing building energy-saving renovation market determines the inherent inevitability of incentive,while unique requirements for the incentive should be satisfied by stage characteristics and individualization of the three entities of the existing building energy-saving renovation market development.Firstly,the analysis of internal and external factors’composition and system influencing the existing construction market development incentive structure was performed.Then,system dynamics was implemented to build the feedback model of incentive effects of market development of existing buildings energy-saving reconstruction.Discussions on the realization path of the incentive for the development of the existing energy-saving building market were also pointed out.Finally,this paper conducted the analysis of the dynamic feedback characteristics and key incentive factors of the incentive for the development of the existing building energy-saving renovation market.Based on the analyses and discussions above,this paper provides methodological guidance and implementation approach for the incentive path selection and policy-making of the existing building energy-saving transformation market,trying to help improve the incentive effectiveness of the market,and also promote healthy and sustainable development of the existing building energy-saving renovation market.展开更多
A dynamic output feedback controller design approach based on cone complementary linearisation procedure is proposed for linear time-invariant （LTI） systems with actuator saturation. First, the estimation of the dom...A dynamic output feedback controller design approach based on cone complementary linearisation procedure is proposed for linear time-invariant （LTI） systems with actuator saturation. First, the estimation of the domain of attraction is given. Then, a design method to find a larger estimation of the domain of attraction is presented. In the process of design, nonconvex conditions are obtained, so a cone complementary linearisation procedure is exploited to solve the nonconvex feasibility problem. Two examples are given to illustrate the efficiency of the design method.展开更多
In this paper, the leader-following consensus problem for multi-agent linear dynamic systems is considered. All agents and leader have identical multi-input multi-output （MIMO） linear dynamics that can be of any ord...In this paper, the leader-following consensus problem for multi-agent linear dynamic systems is considered. All agents and leader have identical multi-input multi-output （MIMO） linear dynamics that can be of any order, and only the output information of each agent is delivered throughout the communication network. When the interaction topology is fixed, the leader-following consensus is attained by Ho~ dynamic output feedback control, and the sufficient condition of robust controllers is equal to the solvability of linear matrix inequality （LMI）. The whole analysis is based on spectral decomposition and an equivalent decoupled structure achieved, and the stability of the system is proved. Finally, we extended the theoretical results to the case that the interaction topology is switching. The simulation results for multiple mobile robots show the effectiveness of the devised methods.展开更多
An experimental method is introduced in this paper to build the dynamics of AMSS (the active magnetic suspension system), which doesn’t depend on system’s physical parameters. The rotor can be reliably suspended und...An experimental method is introduced in this paper to build the dynamics of AMSS (the active magnetic suspension system), which doesn’t depend on system’s physical parameters. The rotor can be reliably suspended under the unit feedback control system designed with the primary dynamic model obtained. Online identification in frequency domain is processed to give the precise model. Comparisons show that the experimental method is much closer to the precise model than the theoretic method based on magnetic circuit law. So this experimental method is a good choice to build the primary dynamic model of AMSS.展开更多
This paper investigates the problem of robust H!fixed-order dynamic output feedback( DOF)controller design for a class of Takagi-Sugeno( T-S) fuzzy affine systems using quantized measurements.Through a state-input aug...This paper investigates the problem of robust H!fixed-order dynamic output feedback( DOF)controller design for a class of Takagi-Sugeno( T-S) fuzzy affine systems using quantized measurements.Through a state-input augmentation method,some sufficient conditions for controller synthesis are developed based upon piecewise quadratic Lyapunov functions( PQLFs) in terms of LMIs. Two illustrative studies are conducted to verify the effectiveness of the proposed controller synthesis approach.展开更多
In this paper, a Duffing oscillator model with delayed velocity feedback is considered. Applying the time delayed feedback control method and delayed differential equation theory, we establish some criteria which ensu...In this paper, a Duffing oscillator model with delayed velocity feedback is considered. Applying the time delayed feedback control method and delayed differential equation theory, we establish some criteria which ensure the stability and the existence of Hopf bifurcation of the model. By choosing the delay as bifurcation parameter and analyzing the associated characteristic equation,the existence of bifurcation parameter point is determined. We found that if the time delay is chosen as a bifurcation parameter,Hopf bifurcation occurs when the time delay is changed through a series of critical values. Some numerical simulations show that the designed feedback controllers not only delay the onset of Hopf bifurcation, but also enlarge the stability region for the model.展开更多
Many difficult (often NP-complete) optimization problems can be solved efficiently on graphs of small tree-width with a given tree-decomposition.In this paper,it is discussed how to solve the minimum feedback vertex s...Many difficult (often NP-complete) optimization problems can be solved efficiently on graphs of small tree-width with a given tree-decomposition.In this paper,it is discussed how to solve the minimum feedback vertex set problem and the minimum vertex feedback edge set problem efficiently by using dynamic programming on a tree-decomposition.展开更多
Microwave pre-treatment is considered as a promising technique for alleviating cutter wear. This paper introduces a high-power microwave-induced fracturing system for hard rock. The test system consists of a high-powe...Microwave pre-treatment is considered as a promising technique for alleviating cutter wear. This paper introduces a high-power microwave-induced fracturing system for hard rock. The test system consists of a high-power microwave subsystem (100 kW), a true triaxial testing machine, a dynamic monitoring subsystem, and an electromagnetic shielding subsystem. It can realize rapid microwave-induced fracturing, intelligent tuning of impedance, dynamic feedback under strong microwave fields, and active control of microwave parameters by addressing the following issues: the instability and insecurity of the system, the discharge breakdown between coaxial lines during high-power microwave output, and a lack of feedback of rock-microwave response. In this study, microwave-induced surface and borehole fracturing tests under true triaxial stress were carried out. Experimental comparisons imply that high-power microwave irradiation can reduce the fracturing time of hard rock and that the fracture range (160 mm) of a 915-MHz microwave source is about three times that of 2.45 GHz. After microwave-induced borehole fracturing, many tensile cracks occur on the rock surface and in the borehole: the maximum reduction of the P-wave velocity is 12.8%. The test results show that a high-power microwave source of 915 MHz is more conducive to assisting mechanical rock breaking and destressing. The system can promote the development of microwave-assisted rock breaking equipment.展开更多
This paper discusses the robust quadratic stabilization control problem for stochastic uncertain systems, where the uncertain matrix is norm bounded, and the external disturbance is a stocbastic process, Two kinds of ...This paper discusses the robust quadratic stabilization control problem for stochastic uncertain systems, where the uncertain matrix is norm bounded, and the external disturbance is a stocbastic process, Two kinds of controllers are designed, which include state feedback case and output feedback case. The conditions for the robust quadratic stabilization of stochastic uncertain systems are given via linear matrix inequalities. The detailed design methods are presented. Numerical examples show the effectiveness of our results.展开更多
基金supported by the National Natural Science Foundation of China (No.60874002)the Key Program of Scientific Innovation of Shanghai Education Committee (No.09zz158)the Shanghai Key Discipline (No.S30501)
文摘This paper investigates the visual servoing robust stabilization of nonholonomic mobile robots. The calibration of visual parameters is not only complicated, but also needs great consumption of calculated time so that the accurate calibration is impossible in some situations for high requirement of real timing. Hence, it is interesting and important to consider the design of stabilizing controllers for nonholonomic kinematic systems with uncalibrated visual parameters. A novel uncertain model of these nonholonomic kinematic systems is proposed. Based on this model, a stabilizing controller is discussed by using dynamic feedback and two-step techniques. The proposed robust controller makes the mobile robot image pose and the orientation converge to the desired configuration despite the lack of depth information and the lack of precise visual parameters. The stability of the closed loop system is rigorously proved. The simulation is given to show the effectiveness of the presented controllers.
文摘Objective:To investigate the impact of precise nursing care based on dynamic nursing quality feedback model on the postoperative recovery of elderly patients undergoing radical resection for colon cancer,with a particular focus on its effects on psychological flexibility.Methods:Medical records of 124 elderly patients undergoing radical resection for colon cancer at The First Affiliated Hospital of Baotou Medical College between January 2021 and May 2024 were retrospectively analyzed in this study.Based on the received nursing interventions,the patients were divided into a control group(standard nursing care)and an observation group(precise nursing care based on a dynamic nursing quality feedback model).Results:The observation group exhibited significantly higher levels of hemoglobin,prealbumin,and albumin compared to the control group.Additionally,the observation group had lower scores in somatization,interpersonal sensitivity,depression,anxiety,obsessions-compulsions,hostility,phobic anxiety,psychoticism,and paranoid ideation.The observation group also demonstrated higher scores in active coping,self-efficacy,and the management of emotions,life,and symptoms.Improvements were also observed in nursing quality,perioperative intervention,satisfaction with rehabilitation guidance,and awareness of regular reexaminations,diet intervention,and complication prevention(all with P<0.05).Conclusion:Precise nursing based on a dynamic nursing quality feedback model can improve nutritional status and medical coping style,reduce psychological issues,and enhance self-management abilities in elderly patients following radical resection of colon cancer.Additionally,it increases nursing satisfaction and raises awareness regarding the importance of regular reexaminations and complication prevention.
基金supported in part by the National Basic Research Program of China("973"Program)(No.2013CB329102).
文摘An adaptive dynamic load balancing algorithm based on QoS is proposed to improve the performance of load balancing in distributed file system,combining the advantages of a variety of load balancing algorithms.The new algorithm uses a tuple containing the number of files and the total file size as the QoS measure for the requested task.The master node sets a threshold for the requested task based on the QoS to filter storage nodes that meet the requirements of the task.In order to guarantee the reliability of the new algorithm,we consider the impact of CPU utilization,memory usage,disk IO occupancy rate,network bandwidth usage and hard disk usage on load balancing performance when calculating the real-time load balancing of storage nodes.The heterogeneity of the network is considered when the master node schedule task assignments to ensure the fairness of the algorithm.The comprehensive evaluation value is determined based the performance load ratio,which is calculated from the real-time load value of the storage node and a performance value after normalization.The master node assigns tasks to the storage node with the highest comprehensive evaluation value.The storage nodes provide adaptive feedback based on changes in the degree of connectivity,rather than periodic update of the load information.The actual distributed file system environment is set up on the server cluster,the performance of the new algorithm is tested through a contrast experiment.The experimental results show that the new algorithm can effectively reduce the average response time of the system,improve throughput,and enable the system load to reach a good balance.
基金Supported by National Natural Science Foundation of China(Grant No.52175059)National Key Research and Development Program of China(Grant No.2018YFB2001100).
文摘Current research on pilot-operated relief valve stability is primarily conducted from the perspective of system dynamics or stability criteria,and most of the existing conclusions focus on the spool shape,damping hole size,and pulsation frequency of the pump.However,the essential factors pertaining to the unstable vibration of relief valves remain ambiguous.In this study,the dynamic behavior of a pilot-operated relief valve is investigated using the frequency-domain method.The result suggests that the dynamic pressure feedback orifice is vital to the dynamic characteristics of the valve.A large orifice has a low flow resistance.In this case,the fluid in the main spring chamber flows freely,which is not conducive to the stability of the relief valve.However,a small orifice may create significant flow resistance,thus restricting fluid flow.In this case,the oil inside the main valve spring chamber is equivalent to a high-stiffness liquid spring.The main mass-spring vibration system has a natural frequency that differs significantly from the operating frequency of the relief valve,which is conducive to the stability of the relief valve.Good agreement is obtained between the theoretical analysis and experiments.The results indicate that designing a dynamic pressure feedback orifice of an appropriate size is beneficial to improving the stability of hydraulic pilot-operated relief valves.In addition,the dynamic pressure feedback orifice reduces the response speed of the relief valve.This study comprehensively considers the stability,rapidity,and immunity of relief valves and expands current investigations into the dynamic characteristics of relief valves from the perspective of classical control theory,thus revealing the importance of different parameters.
基金supported by the National Natural Science Foundation of China (60574011)College Research Project of Liaoning Province(L2010522)
文摘The problem of the quantized dynamic output feedback controller design for networked control systems is mainly discussed. By using the quantized information of the system measurement output and the control input, a novel networked control system model is described. This model includes many networkinduced features, such as multi-rate sampled-data, quantized signal, time-varying delay and packet dropout. By constructing suitable Lyapunov-Krasovskii functional, a less conservative stabilization criterion is established in terms of linear matrix inequalities. The quantized control strategy involves the updating values of the quantizer parameters μi（i = 1, 2）（μi take on countable sets of values which dependent on the information of the system measurement outputs and the control inputs）. Furthermore, a numerical example is given to illustrate the effectiveness of the proposed method.
基金supported by the National Natural Science Foundation of China(61821004,U1964207,20221017-10)。
文摘This paper presents a novel fixed-time stabilization control(FSC)method for a class of strict-feedback nonlinear systems involving unmodelled system dynamics.The key feature of the proposed method is the design of two dynamic parameters.Specifically,a set of auxiliary variables is first introduced through state transformation.These variables combine the original system states and the two introduced dynamic parameters,facilitating the closed-loop system stability analyses.Then,the two dynamic parameters are delicately designed by utilizing the Lyapunov method,ensuring that all the closed-loop system states are globally fixed-time stable.Compared with existing results,the“explosion of complexity”problem of backstepping control is avoided.Moreover,the two designed dynamic parameters are dependent on system states rather than a time-varying function,thus the proposed controller is still valid beyond the given fixedtime convergence instant.The effectiveness of the proposed method is demonstrated through two practical systems.
基金National Natural Science Foundation of China(61922063)Shanghai International Science and Technology Cooperation Project(18510711100)+4 种基金Shanghai Shuguang Project(18sg18)Shanghai Natural Science Foundation(19zr1461400),Shanghai Sailing Program under grant(20YF1452900)Shanghai Municipal Science and Technology Major Project(2021SHZDZX0100)Shanghai Hong Kong Macao Taiwan Science and Technology Cooperation Project(21550760900)Fundamental Research Funds for the Central Universities.
文摘This paper investigates the system security problem of cyber-physical systems(CPSs),which is not only more practical but also more signi cant to deal with than the detecting faults problem.The purpose of this paper is to nd an optimal attack strategy that maximizes the output error of the attacked system with low energy consumption.Based on a general model of linear time-invariant systems and a key technical lemma,a new optimal attack strategy for the meticulously designed false data injection attack is constructed.It is worth mentioning that compared with the existing model-based attack strategies,the designed one is more general and the corresponding attack strategy is more easily implemented when system states and external input are inaccessible.Key to overcoming the inaccessible information,a dynamic observer in the form of Luenberger is constructed.Finally,a networked magnetic levitation steel ball movement system is applied to illustrate the e ectiveness of the proposed scheme.
文摘This paper deals with the problems of bifurcation suppression and bifurcation suppression with stability of nonlinear systems. Necessary conditions and sufficient conditions for bifurcation suppression via dynamic output feedback are presented; Sufficient conditions for bifurcation suppression with stability via dynamic output feedback are obtained. As an application, a dynamic compensator,which guarantees that the bifurcation point of rotating stall in axial flow compressors is stably suppressed, is constructed.
文摘This paper deals with the dynamic output feedback stabilization problem of deterministic finite automata(DFA).The static form of this problem is defined and solved in previous studies via a set of equivalent conditions.In this paper,the dynamic output feedback(DOF)stabilization of DFAs is defined in which the controller is supposed to be another DFA.The DFA controller will be designed to stabilize the equilibrium point of the main DFA through a set of proposed equivalent conditions.It has been proven that the design problem of DOF stabilization is more feasible than the static output feedback(SOF)stabilization.Three simulation examples are provided to illustrate the results of this paper in more details.The first example considers an instance DFA and develops SOF and DOF controllers for it.The example explains the concepts of the DOF controller and how it will be implemented in the closed-loop DFA.In the second example,a special DFA is provided in which the DOF stabilization is feasible,whereas the SOF stabilization is not.The final example compares the feasibility performance of the SOF and DOF stabilizations through applying them to one hundred random-generated DFAs.The results reveal the superiority of the DOF stabilization.
基金supported by National Natural Science Foundation of China(61922063)Shanghai International Science and Technology Cooperation Project(18510711100)+5 种基金Shanghai Shuguang Project(18sg18)Shanghai Natural Science Foundation(19zr1461400)Shanghai Sailing Program under grant(20YF1452900)Shanghai Municipal Science and Technology Major Project(2021SHZDZX0100)Shanghai Hong Kong Macao Taiwan Science and Technology Cooperation Project(21550760900)Fundamental Research Funds for the Central Universities.
文摘This paper investigates the system security problem of cyber-physical systems(CPSs),which is not only more practical but also more significant to deal with than the detecting faults problem.The purpose of this paper is to find an optimal attack strat-egy that maximizes the output error of the attacked system with low energy consumption.Based on a general model of linear time-invariant systems and a key technical lemma,a new optimal attack strategy for the meticulously designed false data injection attack is constructed.It is worth mentioning that compared with the existing model-based attack strategies,the designed one is more general and the corresponding attack strategy is more easily implemented when system states and external input are inaccessible.Key to overcom-ing the inaccessible information,a dynamic observer in the form of Luenberger is constructed.Finally,a networked magnetic levitation steel ball movement system is applied to illustrate the effectiveness of the proposed scheme.
基金the Young Talent Fund of Association for Science and Technology in Shaanxi,China,un-der grant No.20230513.
文摘The paper considers the problem of determining the position of each handle as the bench dragon coils along the spiral.First,the quantitative searching range of the corresponding polar an-gle of the handle is given according to the traveling path characteristics of each handle coiled in,offering the initial value for the proposed algorithm.Then,a dynamical feedback algorithm for calculating the position of the latter handle is proposed,which avoids the multi-solution problem of solving nonlinear equations.Furthermore,to promote the computational efficiency,the design of iterative parameters based on varying polar angles is discussed.In the simulation environment,the effectiveness of the proposed dynamical feedback algorithm is illustrated.
基金supported by the National Natural Science Foundation of China(Grant No.71872122)Late-stage Subsidy Project of Humanities and Social Sciences of the Ministry of Education of China(Grant No.20JHQ095)+2 种基金Late-stage Subsidy Project of Humanities and Social Sciences of the Ministry of Education of China(Grant No.16JHQ031)Social Science Planning Later Project of Tianjin Province(Grant No.TJGLHQ1403)Higher Education Innovation Team of Tianjin(Grant No.TD13-5006)
文摘The quality of the existing building energy-saving renovation market determines the inherent inevitability of incentive,while unique requirements for the incentive should be satisfied by stage characteristics and individualization of the three entities of the existing building energy-saving renovation market development.Firstly,the analysis of internal and external factors’composition and system influencing the existing construction market development incentive structure was performed.Then,system dynamics was implemented to build the feedback model of incentive effects of market development of existing buildings energy-saving reconstruction.Discussions on the realization path of the incentive for the development of the existing energy-saving building market were also pointed out.Finally,this paper conducted the analysis of the dynamic feedback characteristics and key incentive factors of the incentive for the development of the existing building energy-saving renovation market.Based on the analyses and discussions above,this paper provides methodological guidance and implementation approach for the incentive path selection and policy-making of the existing building energy-saving transformation market,trying to help improve the incentive effectiveness of the market,and also promote healthy and sustainable development of the existing building energy-saving renovation market.
基金Program for New Century Excellent Talents in University (No.NCET-04-0283)the Funds for Creative Research Groups of China (No. 60521003)+3 种基金Program for Changjiang Scholars and Innovative Research Team in University (No. IRT0421)the State KeyProgram of National Natural Science of China (No.60534010)the Funds of National Science of China (No.60674021)the Funds of Ph.D.Program of MOE, China (No.20060145019), the 111 Project (No.B08015).
文摘A dynamic output feedback controller design approach based on cone complementary linearisation procedure is proposed for linear time-invariant （LTI） systems with actuator saturation. First, the estimation of the domain of attraction is given. Then, a design method to find a larger estimation of the domain of attraction is presented. In the process of design, nonconvex conditions are obtained, so a cone complementary linearisation procedure is exploited to solve the nonconvex feasibility problem. Two examples are given to illustrate the efficiency of the design method.
文摘In this paper, the leader-following consensus problem for multi-agent linear dynamic systems is considered. All agents and leader have identical multi-input multi-output （MIMO） linear dynamics that can be of any order, and only the output information of each agent is delivered throughout the communication network. When the interaction topology is fixed, the leader-following consensus is attained by Ho~ dynamic output feedback control, and the sufficient condition of robust controllers is equal to the solvability of linear matrix inequality （LMI）. The whole analysis is based on spectral decomposition and an equivalent decoupled structure achieved, and the stability of the system is proved. Finally, we extended the theoretical results to the case that the interaction topology is switching. The simulation results for multiple mobile robots show the effectiveness of the devised methods.
基金Supported by the National Nature Foundation of China (No.59975073)
文摘An experimental method is introduced in this paper to build the dynamics of AMSS (the active magnetic suspension system), which doesn’t depend on system’s physical parameters. The rotor can be reliably suspended under the unit feedback control system designed with the primary dynamic model obtained. Online identification in frequency domain is processed to give the precise model. Comparisons show that the experimental method is much closer to the precise model than the theoretic method based on magnetic circuit law. So this experimental method is a good choice to build the primary dynamic model of AMSS.
基金Sponsored by the National Natural Science Foundation of China(Grant No.61522306)
文摘This paper investigates the problem of robust H!fixed-order dynamic output feedback( DOF)controller design for a class of Takagi-Sugeno( T-S) fuzzy affine systems using quantized measurements.Through a state-input augmentation method,some sufficient conditions for controller synthesis are developed based upon piecewise quadratic Lyapunov functions( PQLFs) in terms of LMIs. Two illustrative studies are conducted to verify the effectiveness of the proposed controller synthesis approach.
基金supported by National Natural Science Foundation of China(Nos.11261010 and 11101126)Natural Science and Technology Foundation of Guizhou Province(No.J[2015]2025)+1 种基金125 Special Major Science and Technology of Department of Education of Guizhou Province(No.[2012]011)Natural Science Innovation Team Project of Guizhou Province(No.[2013]14)
文摘In this paper, a Duffing oscillator model with delayed velocity feedback is considered. Applying the time delayed feedback control method and delayed differential equation theory, we establish some criteria which ensure the stability and the existence of Hopf bifurcation of the model. By choosing the delay as bifurcation parameter and analyzing the associated characteristic equation,the existence of bifurcation parameter point is determined. We found that if the time delay is chosen as a bifurcation parameter,Hopf bifurcation occurs when the time delay is changed through a series of critical values. Some numerical simulations show that the designed feedback controllers not only delay the onset of Hopf bifurcation, but also enlarge the stability region for the model.
基金Partially supported by the National Natural Science Foundation of China( 1 0 2 71 0 65
文摘Many difficult (often NP-complete) optimization problems can be solved efficiently on graphs of small tree-width with a given tree-decomposition.In this paper,it is discussed how to solve the minimum feedback vertex set problem and the minimum vertex feedback edge set problem efficiently by using dynamic programming on a tree-decomposition.
基金support from the Na-tional Natural Science Foundation of China(Grant No.41827806)the liaoning Revitalization Talent Program of China(Grant No.XLYCYSZX1902).
文摘Microwave pre-treatment is considered as a promising technique for alleviating cutter wear. This paper introduces a high-power microwave-induced fracturing system for hard rock. The test system consists of a high-power microwave subsystem (100 kW), a true triaxial testing machine, a dynamic monitoring subsystem, and an electromagnetic shielding subsystem. It can realize rapid microwave-induced fracturing, intelligent tuning of impedance, dynamic feedback under strong microwave fields, and active control of microwave parameters by addressing the following issues: the instability and insecurity of the system, the discharge breakdown between coaxial lines during high-power microwave output, and a lack of feedback of rock-microwave response. In this study, microwave-induced surface and borehole fracturing tests under true triaxial stress were carried out. Experimental comparisons imply that high-power microwave irradiation can reduce the fracturing time of hard rock and that the fracture range (160 mm) of a 915-MHz microwave source is about three times that of 2.45 GHz. After microwave-induced borehole fracturing, many tensile cracks occur on the rock surface and in the borehole: the maximum reduction of the P-wave velocity is 12.8%. The test results show that a high-power microwave source of 915 MHz is more conducive to assisting mechanical rock breaking and destressing. The system can promote the development of microwave-assisted rock breaking equipment.
基金This work was supported by National Natural Science Foundation of China(No .60474013,60374021,60474001) Mathematics Tianyuan Foundation ofChina (No .10426021) .
文摘This paper discusses the robust quadratic stabilization control problem for stochastic uncertain systems, where the uncertain matrix is norm bounded, and the external disturbance is a stocbastic process, Two kinds of controllers are designed, which include state feedback case and output feedback case. The conditions for the robust quadratic stabilization of stochastic uncertain systems are given via linear matrix inequalities. The detailed design methods are presented. Numerical examples show the effectiveness of our results.
