In this paper we present the control and synchronization of a coupled Bragg acousto-optic bistable map system using nonlinear feedback technology. This nonlinear feedback technology is useful to control a temporally c...In this paper we present the control and synchronization of a coupled Bragg acousto-optic bistable map system using nonlinear feedback technology. This nonlinear feedback technology is useful to control a temporally chaotic system as well as a spatiotemporally chaotic system. It can be extended to synchronize the spatiotemporal chaos. It can work in a wide range of the controlled and synchronized signals, so it can decrease the sensitivity down to a noise level. The synchronization can be obtained by the analysis of the largest conditional Lyapunov exponent spectrum, and easily implemented in practical systems just by adjusting the coupled strength without any pre-knowledge of the dynamic system required.展开更多
For the outputs of two nth-order linear control systems to work insynchronization and meanwhile to track their commands, a H_(infinity) synchronization control schemeis presented. In terms of two uncoupled single vari...For the outputs of two nth-order linear control systems to work insynchronization and meanwhile to track their commands, a H_(infinity) synchronization control schemeis presented. In terms of two uncoupled single variable linear systems, a multivariable coupledsystem is established by choosing one output and the difference of the two outputs as a new outputvector, so that both command tracking and synchronization properties can be demonstrated by aH_(infinity) performance index. To improve the synchronization and trailing performance and toguarantee the system robust stability, the mixed sensitivity H_(infinity), design methodology isadopted. The presented synchronization scheme is then extended to the case where one of the twosystems include two input variables, and then applied to the position synchronization control of awafer-retical stage. The wafer-reticle stage consists of a wafer stage, a reticle coarse stage, anda reticle fine stage. The reticle coarse stage picks up the reticle fine stage. The three stagesought to tack their commands, but synchronization between the wafer stage and the reticle fine stagemust be stressed in the tracking process. In the application, by appropriately determining theweighting matrices for the sensitivity function and the complementary sensitivity function, asatisfactory KL synchronization controller is obtained to realize highly accurate positionsynchronization, and to guarantee tracking performance. The above results are verified by simulationexperiments.展开更多
Grid-forming(GFM)converters can provide inertia support for power grids through control technology,stabilize voltage and frequency,and improve system stability,unlike traditional grid-following(GFL)converters.Therefor...Grid-forming(GFM)converters can provide inertia support for power grids through control technology,stabilize voltage and frequency,and improve system stability,unlike traditional grid-following(GFL)converters.Therefore,in future“double high”power systems,research on the control technology of GFM converters will become an urgent demand.In this paper,we first introduce the basic principle of GFM control and then present five currently used control strategies for GFM converters:droop control,power synchronization control(PSC),virtual synchronous machine control(VSM),direct power control(DPC),and virtual oscillator control(VOC).These five strategies can independently establish voltage phasors to provide inertia to the system.Among these,droop control is the most widely used strategy.PSC and VSM are strategies that simulate the mechanical characteristics of synchronous generators;thus,they are more accurate than droop control.DPC regulates the active power and reactive power directly,with no inner current controller,and VOC is a novel method under study using an oscillator circuit to realize synchronization.Finally,we highlight key technologies and research directions to be addressed in the future.展开更多
Based on the three-dimensional Liu chaotic system, this paper appends a feedback variable to construct a novel hyperchaotic Liu system. Then, a control signal is further added to construct a novel nonautonomous hyperc...Based on the three-dimensional Liu chaotic system, this paper appends a feedback variable to construct a novel hyperchaotic Liu system. Then, a control signal is further added to construct a novel nonautonomous hyperchaotic Liu system. Through adjusting the frequency of the control signal, the chaotic property of the system can be controlled to show some different dynamic behaviors such as periodic, quasi-periodic, chaotic and hyperchaotic dynamic behaviours. By numerical simulations, the Lyapunov exponent spectrums, bifurcation diagrams and phase diagrams of the two new systems are studied, respectively. Furthermore, the synchronizing circuits of the nonautonomous hyperchaotic Liu system are designed via the synchronization control method of single variable coupling feedback. Finally, the hardware circuits are implemented, and the corresponding waves of chaos are observed by an oscillograph.展开更多
The vertical position of plasma in the HT-7U Tokamak is inherently unstable. In order to realize active stabilization, the response rate of the high-power high-frequency amplifier feeding the active control coils must...The vertical position of plasma in the HT-7U Tokamak is inherently unstable. In order to realize active stabilization, the response rate of the high-power high-frequency amplifier feeding the active control coils must be fast enough. This paper analyzes the paralleling scheme of the power amplifier through two kinds of control mode. One is the synchronous control; the other is the asynchronous control. Via the comparison of the two kinds of control mode, both of their characteristics are given in the text. At last, the analyzed result is verified by a small power experiment.展开更多
A new dual-actuator fatigue loading system of wind turbine blades was designed.Compared with the traditional pendulum loading mode,the masses in this system only moved linearly along the loading direction to increase ...A new dual-actuator fatigue loading system of wind turbine blades was designed.Compared with the traditional pendulum loading mode,the masses in this system only moved linearly along the loading direction to increase the exciting force.However,the two actuators and the blade constituted a complicated non-linear energy transferring system,which led to the non-synchronization of actuators.On-site test results showed that the virtual spindle synchronous strategy commonly used in synchronous control was undesirable and caused the instability of the blade’s amplitude eventually.A cross-coupled control strategy based on the active disturbance rejection algorithm was proposed.Firstly,a control system model was built according to the synchronization error and tracking error.Furthermore,based on arranging the transition process,estimating the system state and error feedback,and compensating disturbance,an active disturbance rejection controller was designed by adopting the optimal control function.Finally,on-site test results showed that the cross-coupled control strategy based on the active disturbance rejection algorithm could ensure the synchronization of two actuators.The maximum speed synchronization error of the two motors was less than 16 RPM,the displacement synchronization error of the two actuators was less than 0.25 mm and approaching zero after 4 seconds,and the peak value of vibration of the blade was less than 5 mm,which satisfied the fatigue test requirement.展开更多
An adaptive synchronization control method is proposed for chaotic permanent magnet synchronous motors based on the property of a passive system. We prove that the controller makes the synchronization error system bet...An adaptive synchronization control method is proposed for chaotic permanent magnet synchronous motors based on the property of a passive system. We prove that the controller makes the synchronization error system between the driving and the response systems not only passive but also asymptotically stable. The simulation results show that the proposed method is effective and robust against uncertainties in the systemic parameters.展开更多
A novel nonlinear control algorithm based on hybrid neural networks ispresented to cope with the high-accuracy synchronization control problem for a dual-actuatorelectrohydraulic drive system which plays an important ...A novel nonlinear control algorithm based on hybrid neural networks ispresented to cope with the high-accuracy synchronization control problem for a dual-actuatorelectrohydraulic drive system which plays an important role for the development of elastomericlaunchers. A new objective function for better synchronization performance is introduced and alearning algorithm to adjust the weights of the neural network, based on the gradient descentalgorithm, is also derived. The hybrid neural network control algorithm guarantees high-accuracysynchronization performance of two motion cylinders and fast dynamic response as well as goodstability of the control system. Prototype test results on the dual-actuator electrohydraulic drivesystem verifys the effectiveness of the proposed approach.展开更多
Unlike the traditional traction power supply system which enables the electrified railway traction sub- station to be connected to power grid in a way of phase rotation, a new generation traction power supply system w...Unlike the traditional traction power supply system which enables the electrified railway traction sub- station to be connected to power grid in a way of phase rotation, a new generation traction power supply system without phase splits is proposed in this paper. Three key techniques used in this system have been discussed. First, a combined co-phase traction power supply system is applied at traction substations for compensating negative sequence current and eliminating phase splits at exits of substations; design method and procedure for this system are presented. Second, a new bilateral traction power supply technology is proposed to eliminate the phase split at section post and reduce the influence of equalizing current on the power grid. Meanwhile, power factor should be adjusted to ensure a proper voltage level of the traction network. Third, a seg- mental power supply technology of traction network is used to divide the power supply arms into several segments, and the synchronous measurement and control technology is applied to diagnose faults and their locations quickly and accurately. Thus, the fault impact can be limited to a min- imum degree. In addition, the economy and reliability of the new generation traction power supply system are analyzed.展开更多
A new kind of generalized reduced-order synchronization of different chaotic systems is proposed in this paper. It is shown that dynamical evolution of third-order oscillator can be synchronized with the canonical pro...A new kind of generalized reduced-order synchronization of different chaotic systems is proposed in this paper. It is shown that dynamical evolution of third-order oscillator can be synchronized with the canonical projection of a fourth-order chaotic system generated through nonsingular states transformation from a cell neural net chaotic system. In this sense, it is said that generalized synchronization is achieved in reduced-order. The synchronization discussed here expands the scope of reduced-order synchronization studied in relevant literatures. In this way, we can achieve generalized reduced-order synchronization between many famous chaotic systems such as the second-order Drifting system and the third-order Lorenz system by designing a fast slide mode controller. Simulation results are provided to verify the operation of the designed synchronization.展开更多
This paper is concerned with the synchronization of delayed neural networks via sampled-data control. A new technique, namely, the free-matrix-based time-dependent discontinuous Lyapunov functional approach, is adopte...This paper is concerned with the synchronization of delayed neural networks via sampled-data control. A new technique, namely, the free-matrix-based time-dependent discontinuous Lyapunov functional approach, is adopted in constructing the Lyapunov functional, which takes advantage of the sampling characteristic of sawtooth input delay. Based on this discontinuous Lyapunov functional, some less conservative synchronization criteria are established to ensure that the slave system is synchronous with the master system. The desired sampled-data controller can be obtained through the use of the linear matrix inequality(LMI) technique. Finally, two numerical examples are provided to demonstrate the effectiveness and the improvements of the proposed methods.展开更多
This paper investigates event-triggered synchronization for complex networks with Markovian jumping parameters.Nonlinear dynamics with Markovian jumping parameters is considered for each node in a complex network. By ...This paper investigates event-triggered synchronization for complex networks with Markovian jumping parameters.Nonlinear dynamics with Markovian jumping parameters is considered for each node in a complex network. By utilizing the proposed event-triggered strategy, and based on the Lyapunov functional method and linear matrix inequality technology,some sufficient conditions for synchronization of complex networks are derived whether the transition rate matrix for the Markov process is completely known or not. Finally, a numerical example is presented to illustrate the effectiveness of the proposed theoretical results.展开更多
In this paper the synchronization for two different fractional-order chaotic systems, capable of guaranteeing synchronization error with prescribed performance, is investigated by means of the fractional-order control...In this paper the synchronization for two different fractional-order chaotic systems, capable of guaranteeing synchronization error with prescribed performance, is investigated by means of the fractional-order control method. By prescribed performance synchronization we mean that the synchronization error converges to zero asymptotically, with convergence rate being no less than a certain prescribed function. A fractional-order synchronization controller and an adaptive fractional-order synchronization controller, which can guarantee the prescribed performance of the synchronization error,are proposed for fractional-order chaotic systems with and without disturbances, respectively. Finally, our simulation studies verify and clarify the proposed method.展开更多
The development of subsea all-electric Christmas trees is an area of focus in the offshore oil industry worldwide.The main difficulties are associated with the development and control strategies for subsea all-electri...The development of subsea all-electric Christmas trees is an area of focus in the offshore oil industry worldwide.The main difficulties are associated with the development and control strategies for subsea all-electric actuators,which are the most criti-cal components of subsea Christmas trees.A single-motor-level fuzzy PID control with an integrated working condition detection mod-ule and a three-motor redundant-level deviation strategy with coupled joint synchronous control were proposed in this paper to real-ize the real time determination of algorithm parameters according to the working conditions,solve the rapid redistribution problems,and maintain the fast speed of the servo motor of the subsea all-electric tree valve actuator.A synchronous control electrical system was built,tested,and verified through simulation analysis.Test results show that the two redundant servo motors can still control the all-electric valve actuator and provide good synchronization control capabilities despite the failure of one servo motor,and the verti-cal and horizontal vibration values of the system are within reasonable ranges.The synchronous control strategy can be applied to the synchronous control problem of subsea all-electric production systems,which is of considerable importance for the development of subsea all-electric production systems.展开更多
This paper proposes a scanner–stage synchronized approach emphasizing a novel control structure for the laser polishing of Inconel 718 components manufactured by selective laser melting in order to address increasing...This paper proposes a scanner–stage synchronized approach emphasizing a novel control structure for the laser polishing of Inconel 718 components manufactured by selective laser melting in order to address increasing demands for high surface quality in metal additive manufacturing.The proposed synchronized control system is composed of a motion decomposition module and an error synthesis module.The experimental results show that stitching errors can be avoided thanks to continuous motion during laser processing.Moreover,in comparison with the existing step-scan method,the processing efficiency of the proposed method is improved by 38.22%and the surface quality of the laser-polished area is significantly enhanced due to a more homogeneous distribution of the laser energy during the material phase change.The proposed synchronized system paves the way for high-speed,high-precision,and large-area laser material processing without stitching errors.展开更多
To solve the problem of attitude synchronization control for spacecraft formation flying(SFF)suffering from external disturbances under a directed communication topology,a sliding mode disturbance observer(SMDO)based ...To solve the problem of attitude synchronization control for spacecraft formation flying(SFF)suffering from external disturbances under a directed communication topology,a sliding mode disturbance observer(SMDO)based on the finite-time control strategy is developed to observe the time-varying external disturbance via estimating the upper bound of its first derivative.Meanwhile,the rotation matrix is employed to describe the attitude of SFF for the purpose of the avoidance of singularity and unwinding phenomenon.As for the attitude synchronization and the tracking control architecture,a sliding mode surface(SMS)is given such that the control objective can be achieved.The effectiveness and the validity of the proposed method are elaborated via theoretical analysis and numerical simulations.展开更多
The impulsive synchronization problem of two identical chaotic ratchets is investigated in this paper. We demonstrate that the impulsive method to control directed transport is applicable when there are multiple co-ex...The impulsive synchronization problem of two identical chaotic ratchets is investigated in this paper. We demonstrate that the impulsive method to control directed transport is applicable when there are multiple co-existing attractors in phase space transporting particles in different directions. Numerical simulations are carried out to illustrate the effectiveness of the proposed method.展开更多
Considering the special characteristics of the redundant parallel manipulator, with emphasis on the variable of structure, the relatively small workspace and the strong coupling relationship among arms, a synchronizat...Considering the special characteristics of the redundant parallel manipulator, with emphasis on the variable of structure, the relatively small workspace and the strong coupling relationship among arms, a synchronization control strategy is presented in this paper. Since in the feedforward, the inertial and the coriolis matrix are designed constant according to the relatively small workspace, position measurement of the endeffector in plane is ignored. Synchronization error and coupling error are introduced to reject the model errors of inertial and coriolis matrix as stated above. Using the method, the errors of driving arms can be reduced, and the synchronization performance among axes can be improved. The stability of the controllers was proved by Lyapunov method. Finally, experimental results show the feasibility of the method.展开更多
Purpose–The objective of this study is to investigate the impact of longitudinal forces on extreme-long heavy-haul trains,providing new insights and methods for their design and operation,thereby enhancing safety,ope...Purpose–The objective of this study is to investigate the impact of longitudinal forces on extreme-long heavy-haul trains,providing new insights and methods for their design and operation,thereby enhancing safety,operational efficiency and track system design.Design/methodology/approach–A longitudinal dynamics simulation model of the super long heavy haul train was established and verified by the braking test data of 30,000 t heavy-haul combination train on the long and steep down grade of Daqing Line.The simulation model was used to analyze the influence of factors on the longitudinal force of super long heavy haul train.Findings–Under normal conditions,the formation length of extreme-long heavy-haul combined train has a small effect on the maximum longitudinal coupler force under full service braking and emergency braking on the straight line.The slope difference of the long and steep down grade has a great impact on the maximum longitudinal coupler force of the extreme-long heavy-haul trains.Under the condition that the longitudinal force does not exceed the safety limit of 2,250 kN under full service braking at the speed of 60 km/h the maximum allowable slope difference of long and steep down grade for 40,000 t super long heavy-haul combined trains is 13‰,and that of 100,000 t is only 5‰.Originality/value–The results will provide important theoretical basis and practical guidance for further improving the transportation efficiency and safety of extreme-long heavy-haul trains.展开更多
A synchronous control of relative attitude and position is required in separated ultraquiet spacecraft, such as drag-free, disturbance-free, and distributed spacecraft. Thus, a twistorbased synchronous sliding mode co...A synchronous control of relative attitude and position is required in separated ultraquiet spacecraft, such as drag-free, disturbance-free, and distributed spacecraft. Thus, a twistorbased synchronous sliding mode control is investigated in this paper to solve the control problem of relative attitude and position among separated spacecraft modules. The twistor-based control design and the stability proof are implemented using the Modified Rodrigues Parameter(MRP).To evaluate the effectiveness of the proposed control method, this paper presents a case study of separated spacecraft flying control considering the mass uncertainty and external disturbances. In addition, a simulation study of the Proportional-Derivative(PD) control is also presented for comparison. The results indicate that the twistor-based sliding mode controller can ensure global asymptotic stability. The states converge fast with ultra-precision and ultra-stability in both the attitude and position. Moreover, the proposed twistor-based sliding mode control system is robust to the mass uncertainty and external disturbances.展开更多
文摘In this paper we present the control and synchronization of a coupled Bragg acousto-optic bistable map system using nonlinear feedback technology. This nonlinear feedback technology is useful to control a temporally chaotic system as well as a spatiotemporally chaotic system. It can be extended to synchronize the spatiotemporal chaos. It can work in a wide range of the controlled and synchronized signals, so it can decrease the sensitivity down to a noise level. The synchronization can be obtained by the analysis of the largest conditional Lyapunov exponent spectrum, and easily implemented in practical systems just by adjusting the coupled strength without any pre-knowledge of the dynamic system required.
基金This project is supported by Japan Society for the Promotion of Sci-ence(No.P01208)National Natural Science Foundation of China (No.60104003).
文摘For the outputs of two nth-order linear control systems to work insynchronization and meanwhile to track their commands, a H_(infinity) synchronization control schemeis presented. In terms of two uncoupled single variable linear systems, a multivariable coupledsystem is established by choosing one output and the difference of the two outputs as a new outputvector, so that both command tracking and synchronization properties can be demonstrated by aH_(infinity) performance index. To improve the synchronization and trailing performance and toguarantee the system robust stability, the mixed sensitivity H_(infinity), design methodology isadopted. The presented synchronization scheme is then extended to the case where one of the twosystems include two input variables, and then applied to the position synchronization control of awafer-retical stage. The wafer-reticle stage consists of a wafer stage, a reticle coarse stage, anda reticle fine stage. The reticle coarse stage picks up the reticle fine stage. The three stagesought to tack their commands, but synchronization between the wafer stage and the reticle fine stagemust be stressed in the tracking process. In the application, by appropriately determining theweighting matrices for the sensitivity function and the complementary sensitivity function, asatisfactory KL synchronization controller is obtained to realize highly accurate positionsynchronization, and to guarantee tracking performance. The above results are verified by simulationexperiments.
基金supported by the National Natural Science Foundation of China(No.52177122)the“Transformational Technologies for Clean Energy and Demonstration”,Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA 21050100)the Youth Innovation Promotion Association CAS(No.2018170)。
文摘Grid-forming(GFM)converters can provide inertia support for power grids through control technology,stabilize voltage and frequency,and improve system stability,unlike traditional grid-following(GFL)converters.Therefore,in future“double high”power systems,research on the control technology of GFM converters will become an urgent demand.In this paper,we first introduce the basic principle of GFM control and then present five currently used control strategies for GFM converters:droop control,power synchronization control(PSC),virtual synchronous machine control(VSM),direct power control(DPC),and virtual oscillator control(VOC).These five strategies can independently establish voltage phasors to provide inertia to the system.Among these,droop control is the most widely used strategy.PSC and VSM are strategies that simulate the mechanical characteristics of synchronous generators;thus,they are more accurate than droop control.DPC regulates the active power and reactive power directly,with no inner current controller,and VOC is a novel method under study using an oscillator circuit to realize synchronization.Finally,we highlight key technologies and research directions to be addressed in the future.
基金Project supported by the National Natural Science Foundation of China (Grant No 60572089)the Natural Science Foundation of Chongqing (Grant No CSTC,2008BB2087)
文摘Based on the three-dimensional Liu chaotic system, this paper appends a feedback variable to construct a novel hyperchaotic Liu system. Then, a control signal is further added to construct a novel nonautonomous hyperchaotic Liu system. Through adjusting the frequency of the control signal, the chaotic property of the system can be controlled to show some different dynamic behaviors such as periodic, quasi-periodic, chaotic and hyperchaotic dynamic behaviours. By numerical simulations, the Lyapunov exponent spectrums, bifurcation diagrams and phase diagrams of the two new systems are studied, respectively. Furthermore, the synchronizing circuits of the nonautonomous hyperchaotic Liu system are designed via the synchronization control method of single variable coupling feedback. Finally, the hardware circuits are implemented, and the corresponding waves of chaos are observed by an oscillograph.
基金The project supported by the National Meg-Science Engineering Project of Chinese Goverment
文摘The vertical position of plasma in the HT-7U Tokamak is inherently unstable. In order to realize active stabilization, the response rate of the high-power high-frequency amplifier feeding the active control coils must be fast enough. This paper analyzes the paralleling scheme of the power amplifier through two kinds of control mode. One is the synchronous control; the other is the asynchronous control. Via the comparison of the two kinds of control mode, both of their characteristics are given in the text. At last, the analyzed result is verified by a small power experiment.
基金the National Key R&D Program of China,Grant No.2018YFB1501203Meanwhile,this research was funded by the Natural Science Foundation of Shandong,Grant No.ZR2019MEE076And the work in this paper has partly received funding from the National Key R&D Program of Shandong,Grant No.2019GGX104001.
文摘A new dual-actuator fatigue loading system of wind turbine blades was designed.Compared with the traditional pendulum loading mode,the masses in this system only moved linearly along the loading direction to increase the exciting force.However,the two actuators and the blade constituted a complicated non-linear energy transferring system,which led to the non-synchronization of actuators.On-site test results showed that the virtual spindle synchronous strategy commonly used in synchronous control was undesirable and caused the instability of the blade’s amplitude eventually.A cross-coupled control strategy based on the active disturbance rejection algorithm was proposed.Firstly,a control system model was built according to the synchronization error and tracking error.Furthermore,based on arranging the transition process,estimating the system state and error feedback,and compensating disturbance,an active disturbance rejection controller was designed by adopting the optimal control function.Finally,on-site test results showed that the cross-coupled control strategy based on the active disturbance rejection algorithm could ensure the synchronization of two actuators.The maximum speed synchronization error of the two motors was less than 16 RPM,the displacement synchronization error of the two actuators was less than 0.25 mm and approaching zero after 4 seconds,and the peak value of vibration of the blade was less than 5 mm,which satisfied the fatigue test requirement.
基金Project supported by the Key Program of National Natural Science Foundation of China (Grant No. 50937001)the National Natural Science Foundation of China (Grant Nos. 10862001 and 10947011)the Construction of Key Laboratories in Universities of Guangxi,China (Grant No. 200912)
文摘An adaptive synchronization control method is proposed for chaotic permanent magnet synchronous motors based on the property of a passive system. We prove that the controller makes the synchronization error system between the driving and the response systems not only passive but also asymptotically stable. The simulation results show that the proposed method is effective and robust against uncertainties in the systemic parameters.
文摘A novel nonlinear control algorithm based on hybrid neural networks ispresented to cope with the high-accuracy synchronization control problem for a dual-actuatorelectrohydraulic drive system which plays an important role for the development of elastomericlaunchers. A new objective function for better synchronization performance is introduced and alearning algorithm to adjust the weights of the neural network, based on the gradient descentalgorithm, is also derived. The hybrid neural network control algorithm guarantees high-accuracysynchronization performance of two motion cylinders and fast dynamic response as well as goodstability of the control system. Prototype test results on the dual-actuator electrohydraulic drivesystem verifys the effectiveness of the proposed approach.
基金supported by the National Natural Science Funds of China (Nos. 51307143 and 51307142)Technology Research and Development Program of China Railway Corporation (No. 2014J009-B)
文摘Unlike the traditional traction power supply system which enables the electrified railway traction sub- station to be connected to power grid in a way of phase rotation, a new generation traction power supply system without phase splits is proposed in this paper. Three key techniques used in this system have been discussed. First, a combined co-phase traction power supply system is applied at traction substations for compensating negative sequence current and eliminating phase splits at exits of substations; design method and procedure for this system are presented. Second, a new bilateral traction power supply technology is proposed to eliminate the phase split at section post and reduce the influence of equalizing current on the power grid. Meanwhile, power factor should be adjusted to ensure a proper voltage level of the traction network. Third, a seg- mental power supply technology of traction network is used to divide the power supply arms into several segments, and the synchronous measurement and control technology is applied to diagnose faults and their locations quickly and accurately. Thus, the fault impact can be limited to a min- imum degree. In addition, the economy and reliability of the new generation traction power supply system are analyzed.
基金Project supported by the National Natural Science Foundation of China (Grant No 60374037) and the National High Technology Development Program of China (Grant No 2004BA204B08-02).
文摘A new kind of generalized reduced-order synchronization of different chaotic systems is proposed in this paper. It is shown that dynamical evolution of third-order oscillator can be synchronized with the canonical projection of a fourth-order chaotic system generated through nonsingular states transformation from a cell neural net chaotic system. In this sense, it is said that generalized synchronization is achieved in reduced-order. The synchronization discussed here expands the scope of reduced-order synchronization studied in relevant literatures. In this way, we can achieve generalized reduced-order synchronization between many famous chaotic systems such as the second-order Drifting system and the third-order Lorenz system by designing a fast slide mode controller. Simulation results are provided to verify the operation of the designed synchronization.
基金Project supported by the National Natural Science Foundation of China(Grant No.61304064)the Scientific Research Fund of Hunan Provincial Education Department,China(Grant Nos.15B067 and 16C0475)a Discovering Grant from Australian Research Council
文摘This paper is concerned with the synchronization of delayed neural networks via sampled-data control. A new technique, namely, the free-matrix-based time-dependent discontinuous Lyapunov functional approach, is adopted in constructing the Lyapunov functional, which takes advantage of the sampling characteristic of sawtooth input delay. Based on this discontinuous Lyapunov functional, some less conservative synchronization criteria are established to ensure that the slave system is synchronous with the master system. The desired sampled-data controller can be obtained through the use of the linear matrix inequality(LMI) technique. Finally, two numerical examples are provided to demonstrate the effectiveness and the improvements of the proposed methods.
基金Project supported by the National Natural Science Foundation of China(Grant No.11202084)
文摘This paper investigates event-triggered synchronization for complex networks with Markovian jumping parameters.Nonlinear dynamics with Markovian jumping parameters is considered for each node in a complex network. By utilizing the proposed event-triggered strategy, and based on the Lyapunov functional method and linear matrix inequality technology,some sufficient conditions for synchronization of complex networks are derived whether the transition rate matrix for the Markov process is completely known or not. Finally, a numerical example is presented to illustrate the effectiveness of the proposed theoretical results.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11401243 and 61403157)the Fundamental Research Funds for the Central Universities of China(Grant No.GK201504002)the Natural Science Foundation for the Higher Education Institutions of Anhui Province of China(Grant No.KJ2015A256)
文摘In this paper the synchronization for two different fractional-order chaotic systems, capable of guaranteeing synchronization error with prescribed performance, is investigated by means of the fractional-order control method. By prescribed performance synchronization we mean that the synchronization error converges to zero asymptotically, with convergence rate being no less than a certain prescribed function. A fractional-order synchronization controller and an adaptive fractional-order synchronization controller, which can guarantee the prescribed performance of the synchronization error,are proposed for fractional-order chaotic systems with and without disturbances, respectively. Finally, our simulation studies verify and clarify the proposed method.
基金support of the Shandong Provincial Natural Science Foundation(No.ZR2021QE059)the National Natural Science Foundation of China(No.51974169)the Key R&D Program of Shandong Province(No.2019GGX101020).
文摘The development of subsea all-electric Christmas trees is an area of focus in the offshore oil industry worldwide.The main difficulties are associated with the development and control strategies for subsea all-electric actuators,which are the most criti-cal components of subsea Christmas trees.A single-motor-level fuzzy PID control with an integrated working condition detection mod-ule and a three-motor redundant-level deviation strategy with coupled joint synchronous control were proposed in this paper to real-ize the real time determination of algorithm parameters according to the working conditions,solve the rapid redistribution problems,and maintain the fast speed of the servo motor of the subsea all-electric tree valve actuator.A synchronous control electrical system was built,tested,and verified through simulation analysis.Test results show that the two redundant servo motors can still control the all-electric valve actuator and provide good synchronization control capabilities despite the failure of one servo motor,and the verti-cal and horizontal vibration values of the system are within reasonable ranges.The synchronous control strategy can be applied to the synchronous control problem of subsea all-electric production systems,which is of considerable importance for the development of subsea all-electric production systems.
基金The authors would like to acknowledge support from the National Natural Science Foundation of China(51875313 and 51705013)the Open Foundation of the State Key Laboratory of Tribology&Institute of Manufacturing Engineering(SKLT2019C09).
文摘This paper proposes a scanner–stage synchronized approach emphasizing a novel control structure for the laser polishing of Inconel 718 components manufactured by selective laser melting in order to address increasing demands for high surface quality in metal additive manufacturing.The proposed synchronized control system is composed of a motion decomposition module and an error synthesis module.The experimental results show that stitching errors can be avoided thanks to continuous motion during laser processing.Moreover,in comparison with the existing step-scan method,the processing efficiency of the proposed method is improved by 38.22%and the surface quality of the laser-polished area is significantly enhanced due to a more homogeneous distribution of the laser energy during the material phase change.The proposed synchronized system paves the way for high-speed,high-precision,and large-area laser material processing without stitching errors.
基金This work was supported by the National Natural Science Foundation of China(11772185)the Natural Science Foundation of Heilongjiang Province(F2017005)the Fundamental Research Funds for the Central Universities(HEUCFP201770).
文摘To solve the problem of attitude synchronization control for spacecraft formation flying(SFF)suffering from external disturbances under a directed communication topology,a sliding mode disturbance observer(SMDO)based on the finite-time control strategy is developed to observe the time-varying external disturbance via estimating the upper bound of its first derivative.Meanwhile,the rotation matrix is employed to describe the attitude of SFF for the purpose of the avoidance of singularity and unwinding phenomenon.As for the attitude synchronization and the tracking control architecture,a sliding mode surface(SMS)is given such that the control objective can be achieved.The effectiveness and the validity of the proposed method are elaborated via theoretical analysis and numerical simulations.
基金supported by the National Natural Science Foundation of China (Grant No. 10901073)the Program for Innovative Research Team of Jiangnan University
文摘The impulsive synchronization problem of two identical chaotic ratchets is investigated in this paper. We demonstrate that the impulsive method to control directed transport is applicable when there are multiple co-existing attractors in phase space transporting particles in different directions. Numerical simulations are carried out to illustrate the effectiveness of the proposed method.
基金supported by the Natural Science Foundation of China under Grant No.50775170 and 50805111by Xidian University under Grant No.JY10000904011 and JY10000904006
文摘Considering the special characteristics of the redundant parallel manipulator, with emphasis on the variable of structure, the relatively small workspace and the strong coupling relationship among arms, a synchronization control strategy is presented in this paper. Since in the feedforward, the inertial and the coriolis matrix are designed constant according to the relatively small workspace, position measurement of the endeffector in plane is ignored. Synchronization error and coupling error are introduced to reject the model errors of inertial and coriolis matrix as stated above. Using the method, the errors of driving arms can be reduced, and the synchronization performance among axes can be improved. The stability of the controllers was proved by Lyapunov method. Finally, experimental results show the feasibility of the method.
基金subsidized by CHINA RAILWAY Scientific and Technological Research and Development Project(No.2018J008)CHN ENERGY Investment Group Co.,LTD(No.GJNY-20-232),to which,the authors hereby express our appreciation.
文摘Purpose–The objective of this study is to investigate the impact of longitudinal forces on extreme-long heavy-haul trains,providing new insights and methods for their design and operation,thereby enhancing safety,operational efficiency and track system design.Design/methodology/approach–A longitudinal dynamics simulation model of the super long heavy haul train was established and verified by the braking test data of 30,000 t heavy-haul combination train on the long and steep down grade of Daqing Line.The simulation model was used to analyze the influence of factors on the longitudinal force of super long heavy haul train.Findings–Under normal conditions,the formation length of extreme-long heavy-haul combined train has a small effect on the maximum longitudinal coupler force under full service braking and emergency braking on the straight line.The slope difference of the long and steep down grade has a great impact on the maximum longitudinal coupler force of the extreme-long heavy-haul trains.Under the condition that the longitudinal force does not exceed the safety limit of 2,250 kN under full service braking at the speed of 60 km/h the maximum allowable slope difference of long and steep down grade for 40,000 t super long heavy-haul combined trains is 13‰,and that of 100,000 t is only 5‰.Originality/value–The results will provide important theoretical basis and practical guidance for further improving the transportation efficiency and safety of extreme-long heavy-haul trains.
基金supported by the National Natural Science Foundation of China(Nos.51675430,11402044,and U1537213)
文摘A synchronous control of relative attitude and position is required in separated ultraquiet spacecraft, such as drag-free, disturbance-free, and distributed spacecraft. Thus, a twistorbased synchronous sliding mode control is investigated in this paper to solve the control problem of relative attitude and position among separated spacecraft modules. The twistor-based control design and the stability proof are implemented using the Modified Rodrigues Parameter(MRP).To evaluate the effectiveness of the proposed control method, this paper presents a case study of separated spacecraft flying control considering the mass uncertainty and external disturbances. In addition, a simulation study of the Proportional-Derivative(PD) control is also presented for comparison. The results indicate that the twistor-based sliding mode controller can ensure global asymptotic stability. The states converge fast with ultra-precision and ultra-stability in both the attitude and position. Moreover, the proposed twistor-based sliding mode control system is robust to the mass uncertainty and external disturbances.