A hybrid control approach is proposed to achieve the desired performance. Firstly a robust input shaper is designed to reduce the transient vibration and residual vibration of the container efficiently. Then a simple ...A hybrid control approach is proposed to achieve the desired performance. Firstly a robust input shaper is designed to reduce the transient vibration and residual vibration of the container efficiently. Then a simple fuzzy logic controller is designed to eliminate the residual vibration completely in order to guarantee the positioning precision. Such a hybrid approach is simple in structure and readily realizable. Simulation results verify the fine performance of this hybrid control approach. It can achieve perfect elimination of residual vibration and concise positioning of the container load, and it is robust to parameter variations (mainly for cable length) and external disturbances.展开更多
This paper presents a scheme of fault diagnosis for flexible satellites during orbit maneuver. The main contribution of the paper is related to the design of the nonlinear input observer which can avoid false alarm ar...This paper presents a scheme of fault diagnosis for flexible satellites during orbit maneuver. The main contribution of the paper is related to the design of the nonlinear input observer which can avoid false alarm arising from the disturbance from orbit control force. The effects of orbit control force on the fault diagnosis system for satellite attitude control systems, including the disturbing torque caused by the misalignments and the model uncertainty caused by the fuel consumed, are discussed, where standard Lu- enberger observer cannot work well. Then the nonlinear unknown input observer is proposed to decouple faults from disturbance, Besides, a linear matrix inequality approach is adopted to reduce the effect of nonlinear part and model uncertainties on the observer. The numerical and semi-physical simulation demonstrates the effectiveness of the proposed observer for the fault diagnosis system of the satellite during orbit maneuver.展开更多
Inter-area low frequency oscillation in power system is one of the major problems for bulk power transmission through weak tie lines.Use of wide-area signal is more effective than the local area signal in damping out ...Inter-area low frequency oscillation in power system is one of the major problems for bulk power transmission through weak tie lines.Use of wide-area signal is more effective than the local area signal in damping out the inter-area oscillations.Wide area measurement system(WAMS)is convenient to transmit the wide area signal through the communication channel to the remote location.Communication failure is one of the disastrous phenomena in a communication channel.In this paper,a dual input single output(DISO)Hm controller is designed to build the control resiliency by employing two highest observability ranking wide area signals with respect to the critical damping inter-area mode.The proposed controller can provide sufficient damping to the system and also the system remains stabilized if one of the wide-area signals is lost.The time delay is an unwanted phenomenon that degrades the performance of the controllers.The unified Smith predictor approach is used to design a Hm controller to handle the time delay.Kundur's two-area and IEEE-39 bus test systems are considered to verify the effectiveness of the proposed controller.From the simulation results,it is verified that,the proposed controller provides excellent damping performance at normal communication and improves the controller resiliency to counteract the communication failure.展开更多
A new scheme of adaptive control is proposed for a class of linear time-invariant( LTI) dynamical systems,especially in aerospace,with matched parametric uncertainties and input constraints. Based on a typical and c...A new scheme of adaptive control is proposed for a class of linear time-invariant( LTI) dynamical systems,especially in aerospace,with matched parametric uncertainties and input constraints. Based on a typical and conventional direct model reference adaptive control scheme,various modifications have been employed to achieve the goal. "C omposite model reference adaptive control"of higher performance is seam-lessly combined with "positive μ-mod",which consequently results in a smooth tracking trajectory despite of the input constraints. In addition,bounded-gain forgetting is utilized to facilitate faster convergence of parameter estimates. The stability of the closed-loop systemcan be guaranteed by using Lyapunov theory.The merits and effectiveness of the proposed method are illustrated by a numerical example of the longitudinal dynamical systems of a fixed-wing airplane.展开更多
An anti-saturation fault-tolerant adaptive torsional vibration control method with fixed-time prescribed performance for the rolling mill main drive system(RMMDS)was investigated,which is affected by control input sat...An anti-saturation fault-tolerant adaptive torsional vibration control method with fixed-time prescribed performance for the rolling mill main drive system(RMMDS)was investigated,which is affected by control input saturation,actuator faults,sensor measurement errors,and parameter perturbations.First,we gave a continuously differentiable saturation function to approximate the control input saturation characteristic of the RMMDS,translating the saturation characteristic into the matched uncertainty and unknown time-varying gain in the system.Then,an RMMDS mathematical model with unmatched uncertainty and unknown time-varying gain was developed,taking into account the presence of control input saturation,actuator faults,sensor measurement errors,and parameter perturbations.Based on the established mathematical model,an error transformation model of the roll speed tracking was constructed by the equivalent error transformation method.According to the error transformation model,a barrier Lyapunov function and a novel adaptive controller were studied to ensure that the roll speed tracking error always evolves inside a fixed-time asymmetric constraint.Finally,numerical simulations were performed in Matlab/Simulink to verify the effectiveness and superiority of the proposed control method in suppressing the RMMDS torsional vibration.展开更多
This paper studies the formation control problem for the second-order heterogeneous nonlinear multi-agent systems(MASs)with switching topology and quantized control inputs.Compared with formation control under the fix...This paper studies the formation control problem for the second-order heterogeneous nonlinear multi-agent systems(MASs)with switching topology and quantized control inputs.Compared with formation control under the fixed topology,under the switching topology inherent nonlinear dynamics of the agent and the connectivity change of the communication topology are considered.Moreover,to avoid the chattering phenomenon caused by unknown input disturbances,the hysteretic quantizers are incorporated to quantize the input signals.By using the Lyapunov stability theory and leader-follower formation approach,the proposed formation control scheme ensures that all signals of the MASs are semi-globally uniformly ultimately bounded(SGUUB).Finally,the efficiency of the theoretical results is proved by a simulation example.展开更多
To solve the problem of attitude tracking of a rigid spacecraft with an either known or measurable desired attitude trajectory, three types of time-varying sliding mode controls are introduced under consideration of c...To solve the problem of attitude tracking of a rigid spacecraft with an either known or measurable desired attitude trajectory, three types of time-varying sliding mode controls are introduced under consideration of control input constraints. The sliding surfaces of the three types initially pass arbitrary initial values of the system, and then shift or rotate to reach predetermined ones. This way, the system trajectories are always on the sliding surfaces, and the system work is guaranteed to have robustness against parameter uncertainty and external disturbances all the time. The controller parameters are optimized by means of genetic algorithm to minimize the index consisting of the weighted index of squared error (ISE) of the system and the weighted penalty term of violation of control input constraint. The stability is verified with Lyapunov method. Compared with the conventional sliding mode control, simulation results show the proposed algorithm having better robustness against inertia matrix uncertainty and external disturbance torques.展开更多
Controllable canonical forms play important roles in the analysis and design of control systems.In this paper,a fundamental class of discrete-time bilinear systems are considered.Such systems are of interest since,on ...Controllable canonical forms play important roles in the analysis and design of control systems.In this paper,a fundamental class of discrete-time bilinear systems are considered.Such systems are of interest since,on one hand,they have the most complete controllability theory.On the other hand,they can be nearly-controllable even if controllability fails.Firstly,controllability of the systems with positive control inputs is studied and necessary and sufficient algebraic criteria for positive-controllability and positive-near-controllability are derived.Then,controllable canonical forms and nearly-controllable canonical forms of the systems are presented,respectively,where the corresponding transformation matrices are also explicitly constructed.Examples are given to demonstrate the effectiveness of the derived controllability criteria and controllable canonical forms.展开更多
This paper considers the problem of variable structure controller design for singular systems with disturbance in the case of incomplete state information.Some conditions of stabilization are established under the ini...This paper considers the problem of variable structure controller design for singular systems with disturbance in the case of incomplete state information.Some conditions of stabilization are established under the initial state of system is unknown in advance. The controller we designed in terms of the original observer equation(does not require any coordinate change) not only can eliminate impulse on the sliding manifold but also can be easily realized in practice.An example is given to illustrate the design procedure.展开更多
Purpose–The purpose of this paper is to investigate time-optimal control problems for multiple unmanned aerial vehicle(UAV)systems to achieve predefined flying shape.Design/methodology/approach–Two time-optimal prot...Purpose–The purpose of this paper is to investigate time-optimal control problems for multiple unmanned aerial vehicle(UAV)systems to achieve predefined flying shape.Design/methodology/approach–Two time-optimal protocols are proposed for the situations with or without human control input,respectively.Then,Pontryagin’s minimum principle approach is applied to deal with the time-optimal control problems for UAV systems,where the cost function,the initial and terminal conditions are given in advance.Moreover,necessary conditions are derived to ensure that the given performance index is optimal.Findings–The effectiveness of the obtained time-optimal control protocols is verified by two contrastive numerical simulation examples.Consequently,the proposed protocolscan successfully achieve the prescribed flying shape.Originality/value–This paper proposes a solution to solve the time-optimal control problems for multiple UAV systems to achieve predefined flying shape.展开更多
This paper studies the dynamic event-triggered leader-follower consensus of nonlinear multi-agent systems(MASs)under directed weighted graph containing a directed spanning tree,and also considers the effects of distur...This paper studies the dynamic event-triggered leader-follower consensus of nonlinear multi-agent systems(MASs)under directed weighted graph containing a directed spanning tree,and also considers the effects of disturbances and leader of non-zero control inputs in the system.Firstly,a novel distributed control protocol is designed for uncertain disturbances and leader of non-zero control inputs in MASs.Secondly,a novel dynamic event-triggered control(DETC)strategy is proposed,which eliminates the need for continuous communication between agents and reduces communication resources between agents.By introducing dynamic thresholds,the complexity of excluding Zeno behavior within the system is reduced.Finally,the effectiveness of the proposed theory is validated through numerical simulation.展开更多
Instead of replacing traditional input control with output measurements,it is important to link teaching and educational research in such a way that competence measurements not only measure the levels of demands achie...Instead of replacing traditional input control with output measurements,it is important to link teaching and educational research in such a way that competence measurements not only measure the levels of demands achieved by learners but also the quality and effectiveness of teaching.Originality/Value:The train of thought overcomes the juxtaposition of philosophy of education and empirical research and shows how the two can cooperate theoretically and empirically.展开更多
This paper investigates a formation control problem of fixed-wing Unmanned Aerial Vehicle(UAV) swarms. A group-based hierarchical architecture is established among the UAVs, which decomposes all the UAVs into several ...This paper investigates a formation control problem of fixed-wing Unmanned Aerial Vehicle(UAV) swarms. A group-based hierarchical architecture is established among the UAVs, which decomposes all the UAVs into several distinct and non-overlapping groups. In each group, the UAVs form hierarchies with one UAV selected as the group leader. All group leaders execute coordinated path following to cooperatively handle the mission process among different groups, and the remaining followers track their direct leaders to achieve the inner-group coordination. More specifically, for a group leader, a virtual target moving along its desired path is assigned for the UAV, and an updating law is proposed to coordinate all the group leaders’ virtual targets;for a follower UAV, the distributed leader-following formation control law is proposed to make the follower’s heading angle coincide with its direct leader, while keeping the desired relative position with respect to its direct leader. The proposed control law guarantees the globally asymptotic stability of the whole closed-loop swarm system under the control input constraints of fixed-wing UAVs. Theoretical proofs and numerical simulations are provided, which corroborate the effectiveness of the proposed method.展开更多
基金This project is supported by National Hi-tech Research and DevelopmentProgram of China (863 Program, No.2002AA412010).
文摘A hybrid control approach is proposed to achieve the desired performance. Firstly a robust input shaper is designed to reduce the transient vibration and residual vibration of the container efficiently. Then a simple fuzzy logic controller is designed to eliminate the residual vibration completely in order to guarantee the positioning precision. Such a hybrid approach is simple in structure and readily realizable. Simulation results verify the fine performance of this hybrid control approach. It can achieve perfect elimination of residual vibration and concise positioning of the container load, and it is robust to parameter variations (mainly for cable length) and external disturbances.
基金supported by the National Natural Science Foundation of China (61034005)the Natural Science Foundation of Jiangsu Province (BK2010072)
文摘This paper presents a scheme of fault diagnosis for flexible satellites during orbit maneuver. The main contribution of the paper is related to the design of the nonlinear input observer which can avoid false alarm arising from the disturbance from orbit control force. The effects of orbit control force on the fault diagnosis system for satellite attitude control systems, including the disturbing torque caused by the misalignments and the model uncertainty caused by the fuel consumed, are discussed, where standard Lu- enberger observer cannot work well. Then the nonlinear unknown input observer is proposed to decouple faults from disturbance, Besides, a linear matrix inequality approach is adopted to reduce the effect of nonlinear part and model uncertainties on the observer. The numerical and semi-physical simulation demonstrates the effectiveness of the proposed observer for the fault diagnosis system of the satellite during orbit maneuver.
基金support by the Central Power Research Institute,India(CPRI/RD/RSOP/GRANT/2015)
文摘Inter-area low frequency oscillation in power system is one of the major problems for bulk power transmission through weak tie lines.Use of wide-area signal is more effective than the local area signal in damping out the inter-area oscillations.Wide area measurement system(WAMS)is convenient to transmit the wide area signal through the communication channel to the remote location.Communication failure is one of the disastrous phenomena in a communication channel.In this paper,a dual input single output(DISO)Hm controller is designed to build the control resiliency by employing two highest observability ranking wide area signals with respect to the critical damping inter-area mode.The proposed controller can provide sufficient damping to the system and also the system remains stabilized if one of the wide-area signals is lost.The time delay is an unwanted phenomenon that degrades the performance of the controllers.The unified Smith predictor approach is used to design a Hm controller to handle the time delay.Kundur's two-area and IEEE-39 bus test systems are considered to verify the effectiveness of the proposed controller.From the simulation results,it is verified that,the proposed controller provides excellent damping performance at normal communication and improves the controller resiliency to counteract the communication failure.
基金Supported by Deep Exploration Technology and Experimentation Project(201311194-04)
文摘A new scheme of adaptive control is proposed for a class of linear time-invariant( LTI) dynamical systems,especially in aerospace,with matched parametric uncertainties and input constraints. Based on a typical and conventional direct model reference adaptive control scheme,various modifications have been employed to achieve the goal. "C omposite model reference adaptive control"of higher performance is seam-lessly combined with "positive μ-mod",which consequently results in a smooth tracking trajectory despite of the input constraints. In addition,bounded-gain forgetting is utilized to facilitate faster convergence of parameter estimates. The stability of the closed-loop systemcan be guaranteed by using Lyapunov theory.The merits and effectiveness of the proposed method are illustrated by a numerical example of the longitudinal dynamical systems of a fixed-wing airplane.
基金supported by Central Government to Guide local scientific and Technological Development of Hebei Province(No.216Z1902G)Major Program of National Natural Science Foundation of China(U20A20332)+1 种基金Natural Science Foundation of Hebei Province(A2022203024)Provincial Key Laboratory Performance Subsidy Project(22567612H).
文摘An anti-saturation fault-tolerant adaptive torsional vibration control method with fixed-time prescribed performance for the rolling mill main drive system(RMMDS)was investigated,which is affected by control input saturation,actuator faults,sensor measurement errors,and parameter perturbations.First,we gave a continuously differentiable saturation function to approximate the control input saturation characteristic of the RMMDS,translating the saturation characteristic into the matched uncertainty and unknown time-varying gain in the system.Then,an RMMDS mathematical model with unmatched uncertainty and unknown time-varying gain was developed,taking into account the presence of control input saturation,actuator faults,sensor measurement errors,and parameter perturbations.Based on the established mathematical model,an error transformation model of the roll speed tracking was constructed by the equivalent error transformation method.According to the error transformation model,a barrier Lyapunov function and a novel adaptive controller were studied to ensure that the roll speed tracking error always evolves inside a fixed-time asymmetric constraint.Finally,numerical simulations were performed in Matlab/Simulink to verify the effectiveness and superiority of the proposed control method in suppressing the RMMDS torsional vibration.
基金supported by the National Natural Science Foundation of China under Grant Nos.U22A2043 and 61822307。
文摘This paper studies the formation control problem for the second-order heterogeneous nonlinear multi-agent systems(MASs)with switching topology and quantized control inputs.Compared with formation control under the fixed topology,under the switching topology inherent nonlinear dynamics of the agent and the connectivity change of the communication topology are considered.Moreover,to avoid the chattering phenomenon caused by unknown input disturbances,the hysteretic quantizers are incorporated to quantize the input signals.By using the Lyapunov stability theory and leader-follower formation approach,the proposed formation control scheme ensures that all signals of the MASs are semi-globally uniformly ultimately bounded(SGUUB).Finally,the efficiency of the theoretical results is proved by a simulation example.
文摘To solve the problem of attitude tracking of a rigid spacecraft with an either known or measurable desired attitude trajectory, three types of time-varying sliding mode controls are introduced under consideration of control input constraints. The sliding surfaces of the three types initially pass arbitrary initial values of the system, and then shift or rotate to reach predetermined ones. This way, the system trajectories are always on the sliding surfaces, and the system work is guaranteed to have robustness against parameter uncertainty and external disturbances all the time. The controller parameters are optimized by means of genetic algorithm to minimize the index consisting of the weighted index of squared error (ISE) of the system and the weighted penalty term of violation of control input constraint. The stability is verified with Lyapunov method. Compared with the conventional sliding mode control, simulation results show the proposed algorithm having better robustness against inertia matrix uncertainty and external disturbance torques.
基金supported by the National Natural Science Foundation of China under Grant Nos.61973014and 61573044。
文摘Controllable canonical forms play important roles in the analysis and design of control systems.In this paper,a fundamental class of discrete-time bilinear systems are considered.Such systems are of interest since,on one hand,they have the most complete controllability theory.On the other hand,they can be nearly-controllable even if controllability fails.Firstly,controllability of the systems with positive control inputs is studied and necessary and sufficient algebraic criteria for positive-controllability and positive-near-controllability are derived.Then,controllable canonical forms and nearly-controllable canonical forms of the systems are presented,respectively,where the corresponding transformation matrices are also explicitly constructed.Examples are given to demonstrate the effectiveness of the derived controllability criteria and controllable canonical forms.
文摘This paper considers the problem of variable structure controller design for singular systems with disturbance in the case of incomplete state information.Some conditions of stabilization are established under the initial state of system is unknown in advance. The controller we designed in terms of the original observer equation(does not require any coordinate change) not only can eliminate impulse on the sliding manifold but also can be easily realized in practice.An example is given to illustrate the design procedure.
基金supported by the National Natural Science Foundation of China under Grant Nos 61602163 and 61471163the Science Fund for Distinguished Young Scholars of Hubei Province under Grant No.2017CFA034the Natural Science Foundation of Hubei Province under 2016CFC735.The Hubei Education Department Science and Technology Research Program for young talents under Grant No.Q20182503.
文摘Purpose–The purpose of this paper is to investigate time-optimal control problems for multiple unmanned aerial vehicle(UAV)systems to achieve predefined flying shape.Design/methodology/approach–Two time-optimal protocols are proposed for the situations with or without human control input,respectively.Then,Pontryagin’s minimum principle approach is applied to deal with the time-optimal control problems for UAV systems,where the cost function,the initial and terminal conditions are given in advance.Moreover,necessary conditions are derived to ensure that the given performance index is optimal.Findings–The effectiveness of the obtained time-optimal control protocols is verified by two contrastive numerical simulation examples.Consequently,the proposed protocolscan successfully achieve the prescribed flying shape.Originality/value–This paper proposes a solution to solve the time-optimal control problems for multiple UAV systems to achieve predefined flying shape.
基金supported by the National Natural Science Foundation of China(62173175)。
文摘This paper studies the dynamic event-triggered leader-follower consensus of nonlinear multi-agent systems(MASs)under directed weighted graph containing a directed spanning tree,and also considers the effects of disturbances and leader of non-zero control inputs in the system.Firstly,a novel distributed control protocol is designed for uncertain disturbances and leader of non-zero control inputs in MASs.Secondly,a novel dynamic event-triggered control(DETC)strategy is proposed,which eliminates the need for continuous communication between agents and reduces communication resources between agents.By introducing dynamic thresholds,the complexity of excluding Zeno behavior within the system is reduced.Finally,the effectiveness of the proposed theory is validated through numerical simulation.
文摘Instead of replacing traditional input control with output measurements,it is important to link teaching and educational research in such a way that competence measurements not only measure the levels of demands achieved by learners but also the quality and effectiveness of teaching.Originality/Value:The train of thought overcomes the juxtaposition of philosophy of education and empirical research and shows how the two can cooperate theoretically and empirically.
基金supported in part by National Natural Science Foundation of China (Nos. 61973309, 61801494 and61702528)in part by Hunan Provincial Innovation Foundation for Postgraduate,China (No. CX2017B014)。
文摘This paper investigates a formation control problem of fixed-wing Unmanned Aerial Vehicle(UAV) swarms. A group-based hierarchical architecture is established among the UAVs, which decomposes all the UAVs into several distinct and non-overlapping groups. In each group, the UAVs form hierarchies with one UAV selected as the group leader. All group leaders execute coordinated path following to cooperatively handle the mission process among different groups, and the remaining followers track their direct leaders to achieve the inner-group coordination. More specifically, for a group leader, a virtual target moving along its desired path is assigned for the UAV, and an updating law is proposed to coordinate all the group leaders’ virtual targets;for a follower UAV, the distributed leader-following formation control law is proposed to make the follower’s heading angle coincide with its direct leader, while keeping the desired relative position with respect to its direct leader. The proposed control law guarantees the globally asymptotic stability of the whole closed-loop swarm system under the control input constraints of fixed-wing UAVs. Theoretical proofs and numerical simulations are provided, which corroborate the effectiveness of the proposed method.