This paper is concerned with event-triggered control of discrete-time systems with or without input saturation.First,an accumulative-error-based event-triggered scheme is devised for control updates.When the accumulat...This paper is concerned with event-triggered control of discrete-time systems with or without input saturation.First,an accumulative-error-based event-triggered scheme is devised for control updates.When the accumulated error between the current state and the latest control update exceeds a certain threshold,an event is triggered.Such a scheme can ensure the event-generator works at a relatively low rate rather than falls into hibernation especially after the system steps into its steady state.Second,the looped functional method for continuous-time systems is extended to discrete-time systems.By introducing an innovative looped functional that links the event-triggered scheme,some sufficient conditions for the co-design of control gain and event-triggered parameters are obtained in terms of linear matrix inequalities with a couple of tuning parameters.Then,the proposed method is applied to discrete-time systems with input saturation.As a result,both suitable control gains and event-triggered parameters are also co-designed to ensure the system trajectories converge to the region of attraction.Finally,an unstable reactor system and an inverted pendulum system are given to show the effectiveness of the proposed method.展开更多
A robust Adaptive Discrete-time Sliding Mode Controller (ADSMC) is formulated, and is applied to control the pitch motion of a simulated Flapping-Wing Micro Air Vehicle (FWMAV). There is great potential for FWMAVs to ...A robust Adaptive Discrete-time Sliding Mode Controller (ADSMC) is formulated, and is applied to control the pitch motion of a simulated Flapping-Wing Micro Air Vehicle (FWMAV). There is great potential for FWMAVs to be used as aerial tools to assist with gathering data and surveying environments. Thanks to modern manufacturing and technology, along with an increased comprehension behind the aerodynamics of wing flaps, these vehicles are now a reality, though not without limitations. Given their diminutive size, FWMAVs are susceptible to real-world disturbances, such as wind gusts, and are sensitive to particular variations in their build quality. While external forces such as wind gusts can be reasonably bounded, the unknown variations in the state may be difficult to characterize or bound without affecting performance. To address these problems, an ADSMC is developed. First, the FWMAV model is converted from continuous-time to discrete-time. Second, an ADSMC for the newly discretized FWMAV model is developed. Using this controller, the trajectory tracking performance of the FWMAV is assessed against a traditional discrete sliding mode controller, and is found to have a decreased chattering frequency and decreased control effort for the same task. Therefore, the ADSMC is assessed as the superior controller, despite being completely unaware of the model parameters or wind gust.展开更多
The paper presents an adaptive controller formulated for a class of nonaffine discrete-time systems with non-strict forms and unknown dynamics.The controller operates based solely on the measured output,thus obviating...The paper presents an adaptive controller formulated for a class of nonaffine discrete-time systems with non-strict forms and unknown dynamics.The controller operates based solely on the measured output,thus obviating the need for knowledge of the physical order of the controlled plant.Utilizing an ideal solution and equivalent dynamics,the approach integrates an adaptive network with feedback and robust controllers to establish a closed-loop system.A learning law is derived under practical conditions of the designed parameters,ensuring effective closed-loop performance based on pure-output feedback.The controller’s effectiveness is validated through both numerical and experimental systems,with results meeting the conditions specified in the main theorem.Comparative analysis highlights the controller’s highly satisfactory performance and its advantages.This research offers a promising approach to adaptive control for discrete-time systems with non-strict dynamics,providing practical solutions for systems with unknown dynamics and indeterminate system order.展开更多
In this work,a self-healing predictive control method for discrete-time nonlinear systems is presented to ensure the system can be safely operated under abnormal states.First,a robust MPC controller for the normal cas...In this work,a self-healing predictive control method for discrete-time nonlinear systems is presented to ensure the system can be safely operated under abnormal states.First,a robust MPC controller for the normal case is constructed,which can drive the system to the equilibrium point when the closed-loop states are in the predetermined safe set.In this controller,the tubes are built based on the incremental Lyapunov function to tighten nominal constraints.To deal with the infeasible controller when abnormal states occur,a self-healing predictive control method is further proposed to realize self-healing by driving the system towards the safe set.This is achieved by an auxiliary softconstrained recovery mechanism that can solve the constraint violation caused by the abnormal states.By extending the discrete-time robust control barrier function theory,it is proven that the auxiliary problem provides a predictive control barrier bounded function to make the system asymptotically stable towards the safe set.The theoretical properties of robust recursive feasibility and bounded stability are further analyzed.The efficiency of the proposed controller is verified by a numerical simulation of a continuous stirred-tank reactor process.展开更多
Methods to stabilize discrete-time linear control systems subject to variable sampling rates,i.e.,using state feedback controllers,are well known in the literature.Several recent works address the use of the Tikhonov ...Methods to stabilize discrete-time linear control systems subject to variable sampling rates,i.e.,using state feedback controllers,are well known in the literature.Several recent works address the use of the Tikhonov regularization method,originally designed to attenuate the noise effects on ill-posed problems,with the aim of improving performance and stabilizing approximately controllable dynamical systems.Inspired by these works,we propose the use of a feedback controller designed using the Tikhonov method to regularize discrete-time linear systems subject to varying sampling rates.The goal is to minimize an error function,thus improving the performance of the closed loop system and reducing the possibility of instability.Illustrative examples show the effectiveness of the proposed method.展开更多
A control model of gas supply system is introduced for ion source and an adaptive discrete-time control algorithm to regulate the hydrogen injection. A real-time feedback control system （RFCS） is designed to control...A control model of gas supply system is introduced for ion source and an adaptive discrete-time control algorithm to regulate the hydrogen injection. A real-time feedback control system （RFCS） is designed to control the gas supply for ion source based on the control model and the discrete-time control algorithm. The experimental results have proved that RFCS could regulate the gas supply smoothly, suppress the arc＇s abrupt over-current at the end of the ion source discharging, prolong the discharge pulse and stabilize the ion concentration. With RFCS, the ion source for neutral beam injection has reached its longest pulse with a length of 4.5 seconds in a stable status.展开更多
The main contribution of this paper is to present stability synthesis results for discrete-time piecewise affine （PWA） systems with polytopic time-varying uncertainties and for discrete-time PWA systems with norm-bo...The main contribution of this paper is to present stability synthesis results for discrete-time piecewise affine （PWA） systems with polytopic time-varying uncertainties and for discrete-time PWA systems with norm-bounded uncertainties respectively.The basic idea of the proposed approaches is to construct piecewise-quadratic （PWQ） Lyapunov functions to guarantee the stability of the closed-loop systems.The partition information of the PWA systems is taken into account and each polytopic operating region is outer approximated by an ellipsoid,then sufficient conditions for the robust stabilization are derived and expressed as a set of linear matrix inequalities （LMIs）.Two examples are given to illustrate the proposed theoretical results.展开更多
This study addresses the adaptive control and function projective synchronization problems between 2D Rulkov discrete-time system and Network discrete-time system. Based on backstepping design with three controllers, ...This study addresses the adaptive control and function projective synchronization problems between 2D Rulkov discrete-time system and Network discrete-time system. Based on backstepping design with three controllers, a systematic, concrete and automatic scheme is developed to investigate the function projective synchronization of discretetime chaotic systems. In addition, the adaptive control function is applied to achieve the state synchronization of two discrete-time systems. Numerical results demonstrate the effectiveness of the proposed control scheme.展开更多
Two approximation laws of sliding mode for discrete-time variable structure control systems are proposed to overcome the limitations of the exponential approximation law and the variable rate approximation law. By app...Two approximation laws of sliding mode for discrete-time variable structure control systems are proposed to overcome the limitations of the exponential approximation law and the variable rate approximation law. By applying the proposed approximation laws of sliding mode to discrete-time variable structure control systems, the stability of origin can be guaranteed, and the chattering along the switching surface caused by discrete-time variable structure control can be restrained effectively. In designing of approximation laws, the problem that the system control input is restricted is also considered, which is very important in practical systems. Finally a simulation example shows the effectiveness of the two approximation laws proposed.展开更多
This paper focuses on the problem of non-fragile guaranteed cost control for a class of T-S discrete-time fuzzy bilinear systems（DFBS）.Based on the parallel distributed compensation（PDC） approach,the sufficient co...This paper focuses on the problem of non-fragile guaranteed cost control for a class of T-S discrete-time fuzzy bilinear systems（DFBS）.Based on the parallel distributed compensation（PDC） approach,the sufficient conditions are derived such that the closed-loop system is asymptotically stable and the cost function value is no more than a certain upper bound in the presence of the additive controller gain perturbations.The non-fragile guaranteed cost controller can be obtained by solving a set of bilinear matrix inequalities（BMIs）.The Van de Vusse model is utilized to demonstrate the validity and effectiveness of the proposed approach.展开更多
A novel discrete-time reaching law was proposed for uncertain discrete-time system,which contained process noise and measurement noise.The proposed method reserves all the advantages of discrete-time reaching law,whic...A novel discrete-time reaching law was proposed for uncertain discrete-time system,which contained process noise and measurement noise.The proposed method reserves all the advantages of discrete-time reaching law,which not only decreases the band width of sliding mode and strengthens the system robustness,but also improves the dynamic performance and stability capability of the system.Moreover,a discrete-time sliding mode control strategy based on Kalman filter method was designed,and Kalman filter was employed to eliminate the influence of system noise.Simulation results show that there is no chattering phenomenon in the output of controller and the state variables of controlled system,and the proposed algorithm is also feasible and has strong robustness to external disturbances.展开更多
This paper presents a novel design method for discrete-time repetitive control systems （RCS） based on two-dimensional （2D） discrete-time model. Firstly, the 2D model of an RCS is established by considering both th...This paper presents a novel design method for discrete-time repetitive control systems （RCS） based on two-dimensional （2D） discrete-time model. Firstly, the 2D model of an RCS is established by considering both the control action and the learning action in RCS. Then, through constructing a 2D state feedback controller, the design problem of the RCS is converted to the design problem of a 2D system. Then, using 2D system theory and linear matrix inequality （LMI） method, stability criterion is derived for the system without and with uncertainties, respectively. Parameters of the system can be determined by solving the LMI of the stability criterion. Finally, numerical simulations validate the effectiveness of the proposed method.展开更多
A new variable structure control algorithm based on sliding mode prediction for a class of discrete-time nonlinear systems is presented. By employing a special model to predict future sliding mode value, and combining...A new variable structure control algorithm based on sliding mode prediction for a class of discrete-time nonlinear systems is presented. By employing a special model to predict future sliding mode value, and combining feedback correction and receding horizon optimization methods which are extensively applied on predictive control strategy, a discrete-time variable structure control law is constructed. The closed-loop systems are proved to have robustness to uncertainties with unspecified boundaries. Numerical simulation and pendulum experiment results illustrate that the closed-loop systems possess desired performance, such as strong robustness, fast convergence and chattering elimination.展开更多
This paper presents a distributed control protocol for consensus control of multi-agent systems(MASs) under external disturbances and network imperfections, including communication delay and random packet dropout. To ...This paper presents a distributed control protocol for consensus control of multi-agent systems(MASs) under external disturbances and network imperfections, including communication delay and random packet dropout. To comply with the discrete nature of networked systems, in contrast to most of the existing work for MASs under network imperfections,the agents are modeled by discrete-time dynamics. The communication network is considered to be undirected, its delay is considered to be time-varying but bounded, and its packet dropout is modeled by a Bernoulli distributed white sequence.Sufficient conditions in terms of linear matrix inequalities(LMIs)for asymptotic mean-square consensus stability are derived under network imperfections without considering external disturbances.A desired disturbance attenuation level in the presence of both external disturbances and network imperfections is also provided.A simulation example is given to verify the effectiveness of the proposed approach in coping with network imperfection and disturbances.展开更多
The problem of designing fuzzy static output feedback controller for T-S discrete-time fuzzy bilinear system （DFBS） is presented. Based on parallel distribution compensation method, some sufficient conditions are de...The problem of designing fuzzy static output feedback controller for T-S discrete-time fuzzy bilinear system （DFBS） is presented. Based on parallel distribution compensation method, some sufficient conditions are derived to guarantee the stability of the overall fuzzy system. The stabilization conditions are further formulated into linear matrix inequality （LMI） so that the desired controller can be easily obtained by using the Matlab LMI toolbox. In comparison with the existing results, the drawbacks, such as coordinate transformation, same output matrices, have been elim- inated. Finally, a simulation example shows that the approach is effective.展开更多
This paper develops a discrete-time sliding mode controller with a power rate exponential reaching law approach to enhance the performance of a pneumatic artificial muscle system in both reaching time and chattering r...This paper develops a discrete-time sliding mode controller with a power rate exponential reaching law approach to enhance the performance of a pneumatic artificial muscle system in both reaching time and chattering reduction.The proposed method dynamically adapts to the variation of the switching function,which is based on an exponential term and a power rate term of the sliding surface.Thus,the controlled system can achieve high tracking performance while still obtain chattering-free control.Moreover,the effectiveness of the proposed method is validated through multiple experimental tests,focused on a dual pneumatic artificial muscle system.Finally,experimental results show the effectiveness of the proposed approach in this paper.展开更多
Time-varying network induced delay in the communication channel severely affects the performance of closed loop network control systems. In this paper, a novel idea of compensating the fractional time varying communic...Time-varying network induced delay in the communication channel severely affects the performance of closed loop network control systems. In this paper, a novel idea of compensating the fractional time varying communication delay in the sliding Surface is presented. The fractional time delay in the sensor to controller and controller to actuator channel is approximated using the Thiran approximation technique to design the sliding surface. A discrete-time sliding mode control law is derived using the proposed surface that compensates fractional time delay in sensor to controller and controller to actuator channels for uncertain network control systems. The sufficient condition for closed loop stability of the system is derived using the Lyapunov function. The efficacy of the proposed strategy is supported by the simulation results.展开更多
The robust reliable H∞ control problem for discrete-time Markovian jump systems with actuator failures is studied. A more practical model of actuator failures than outage is considered. Based on the state feedback me...The robust reliable H∞ control problem for discrete-time Markovian jump systems with actuator failures is studied. A more practical model of actuator failures than outage is considered. Based on the state feedback method, the resulting closed-loop systems are reliable in that they remain robust stochastically stable and satisfy a certain level of H∞ disturbance attenuation not only when all actuators are operational, but also in case of some actuator failures, The solvability condition of controllers can be equivalent to a feasibility problem of coupled linear matrix inequalities （LMIs）. A numerical example is also given to illustrate the design procedures and their effectiveness.展开更多
Formation control of discrete-time linear multi-agent systems using directed switching topology is considered in this work via a reduced-order observer, in which a formation control protocol is proposed under the assu...Formation control of discrete-time linear multi-agent systems using directed switching topology is considered in this work via a reduced-order observer, in which a formation control protocol is proposed under the assumption that each directed communication topology has a directed spanning tree. By utilizing the relative outputs of neighboring agents, a reduced-order observer is designed for each following agent. A multi-step control algorithm is established based on the Lyapunov method and the modified discrete-time algebraic Riccati equation. A sufficient condition is given to ensure that the discrete-time linear multi-agent system can achieve the expected leader-following formation.Finally, numerical examples are provided so as to demonstrate the effectiveness of the obtained results.展开更多
基金supported in part by the National Natural Science Foundation of China(62473221)the Natural Science Foundation of Shandong Province,China(ZR2024MF006)Qingdao Natural Science Foundation(24-4-4-zrjj-165-jch)。
文摘This paper is concerned with event-triggered control of discrete-time systems with or without input saturation.First,an accumulative-error-based event-triggered scheme is devised for control updates.When the accumulated error between the current state and the latest control update exceeds a certain threshold,an event is triggered.Such a scheme can ensure the event-generator works at a relatively low rate rather than falls into hibernation especially after the system steps into its steady state.Second,the looped functional method for continuous-time systems is extended to discrete-time systems.By introducing an innovative looped functional that links the event-triggered scheme,some sufficient conditions for the co-design of control gain and event-triggered parameters are obtained in terms of linear matrix inequalities with a couple of tuning parameters.Then,the proposed method is applied to discrete-time systems with input saturation.As a result,both suitable control gains and event-triggered parameters are also co-designed to ensure the system trajectories converge to the region of attraction.Finally,an unstable reactor system and an inverted pendulum system are given to show the effectiveness of the proposed method.
文摘A robust Adaptive Discrete-time Sliding Mode Controller (ADSMC) is formulated, and is applied to control the pitch motion of a simulated Flapping-Wing Micro Air Vehicle (FWMAV). There is great potential for FWMAVs to be used as aerial tools to assist with gathering data and surveying environments. Thanks to modern manufacturing and technology, along with an increased comprehension behind the aerodynamics of wing flaps, these vehicles are now a reality, though not without limitations. Given their diminutive size, FWMAVs are susceptible to real-world disturbances, such as wind gusts, and are sensitive to particular variations in their build quality. While external forces such as wind gusts can be reasonably bounded, the unknown variations in the state may be difficult to characterize or bound without affecting performance. To address these problems, an ADSMC is developed. First, the FWMAV model is converted from continuous-time to discrete-time. Second, an ADSMC for the newly discretized FWMAV model is developed. Using this controller, the trajectory tracking performance of the FWMAV is assessed against a traditional discrete sliding mode controller, and is found to have a decreased chattering frequency and decreased control effort for the same task. Therefore, the ADSMC is assessed as the superior controller, despite being completely unaware of the model parameters or wind gust.
文摘The paper presents an adaptive controller formulated for a class of nonaffine discrete-time systems with non-strict forms and unknown dynamics.The controller operates based solely on the measured output,thus obviating the need for knowledge of the physical order of the controlled plant.Utilizing an ideal solution and equivalent dynamics,the approach integrates an adaptive network with feedback and robust controllers to establish a closed-loop system.A learning law is derived under practical conditions of the designed parameters,ensuring effective closed-loop performance based on pure-output feedback.The controller’s effectiveness is validated through both numerical and experimental systems,with results meeting the conditions specified in the main theorem.Comparative analysis highlights the controller’s highly satisfactory performance and its advantages.This research offers a promising approach to adaptive control for discrete-time systems with non-strict dynamics,providing practical solutions for systems with unknown dynamics and indeterminate system order.
基金supported in part the National Key Research and Development Program of China(2021YFC2902703)Open Foundation of State Key Laboratory of Process Automation in Mining&Metallurgy/Beijing Key Laboratory of Process Automation in Mining&Metallurgy(BGRIMM-KZSKL-2022-6)the National Natural Science Foundation of China(62173078,61873049).
文摘In this work,a self-healing predictive control method for discrete-time nonlinear systems is presented to ensure the system can be safely operated under abnormal states.First,a robust MPC controller for the normal case is constructed,which can drive the system to the equilibrium point when the closed-loop states are in the predetermined safe set.In this controller,the tubes are built based on the incremental Lyapunov function to tighten nominal constraints.To deal with the infeasible controller when abnormal states occur,a self-healing predictive control method is further proposed to realize self-healing by driving the system towards the safe set.This is achieved by an auxiliary softconstrained recovery mechanism that can solve the constraint violation caused by the abnormal states.By extending the discrete-time robust control barrier function theory,it is proven that the auxiliary problem provides a predictive control barrier bounded function to make the system asymptotically stable towards the safe set.The theoretical properties of robust recursive feasibility and bounded stability are further analyzed.The efficiency of the proposed controller is verified by a numerical simulation of a continuous stirred-tank reactor process.
文摘Methods to stabilize discrete-time linear control systems subject to variable sampling rates,i.e.,using state feedback controllers,are well known in the literature.Several recent works address the use of the Tikhonov regularization method,originally designed to attenuate the noise effects on ill-posed problems,with the aim of improving performance and stabilizing approximately controllable dynamical systems.Inspired by these works,we propose the use of a feedback controller designed using the Tikhonov method to regularize discrete-time linear systems subject to varying sampling rates.The goal is to minimize an error function,thus improving the performance of the closed loop system and reducing the possibility of instability.Illustrative examples show the effectiveness of the proposed method.
基金National Natural Science Foundation of China(No.10575105)
文摘A control model of gas supply system is introduced for ion source and an adaptive discrete-time control algorithm to regulate the hydrogen injection. A real-time feedback control system （RFCS） is designed to control the gas supply for ion source based on the control model and the discrete-time control algorithm. The experimental results have proved that RFCS could regulate the gas supply smoothly, suppress the arc＇s abrupt over-current at the end of the ion source discharging, prolong the discharge pulse and stabilize the ion concentration. With RFCS, the ion source for neutral beam injection has reached its longest pulse with a length of 4.5 seconds in a stable status.
基金supported by the National Science Fund of China for Distinguished Young Scholars(No.60725311)
文摘The main contribution of this paper is to present stability synthesis results for discrete-time piecewise affine （PWA） systems with polytopic time-varying uncertainties and for discrete-time PWA systems with norm-bounded uncertainties respectively.The basic idea of the proposed approaches is to construct piecewise-quadratic （PWQ） Lyapunov functions to guarantee the stability of the closed-loop systems.The partition information of the PWA systems is taken into account and each polytopic operating region is outer approximated by an ellipsoid,then sufficient conditions for the robust stabilization are derived and expressed as a set of linear matrix inequalities （LMIs）.Two examples are given to illustrate the proposed theoretical results.
基金supported by the Natural Science Foundation of China under Grant Nos.10747141 and 10735030Zhejiang Provincial Natural Science Foundation under Grant No.605408+3 种基金Ningbo Natural Science Foundation under Grant Nos.2007A610049 and 2008A61001National Basic Research Program of China (973 Program 2007CB814800)Programme for Changjiang Scholars and Innovative Research Team in University (IRT0734)K.C.Wong Magna Fund in Ningbo University
文摘This study addresses the adaptive control and function projective synchronization problems between 2D Rulkov discrete-time system and Network discrete-time system. Based on backstepping design with three controllers, a systematic, concrete and automatic scheme is developed to investigate the function projective synchronization of discretetime chaotic systems. In addition, the adaptive control function is applied to achieve the state synchronization of two discrete-time systems. Numerical results demonstrate the effectiveness of the proposed control scheme.
基金This work was supported by the National Natural Science Foundation of China (No.60274099) and the Foundation of Key Laboratory of Process Industry Automation, Ministry of Education
文摘Two approximation laws of sliding mode for discrete-time variable structure control systems are proposed to overcome the limitations of the exponential approximation law and the variable rate approximation law. By applying the proposed approximation laws of sliding mode to discrete-time variable structure control systems, the stability of origin can be guaranteed, and the chattering along the switching surface caused by discrete-time variable structure control can be restrained effectively. In designing of approximation laws, the problem that the system control input is restricted is also considered, which is very important in practical systems. Finally a simulation example shows the effectiveness of the two approximation laws proposed.
基金supported by the National Natural Science Foundation of China(60374015)
文摘This paper focuses on the problem of non-fragile guaranteed cost control for a class of T-S discrete-time fuzzy bilinear systems（DFBS）.Based on the parallel distributed compensation（PDC） approach,the sufficient conditions are derived such that the closed-loop system is asymptotically stable and the cost function value is no more than a certain upper bound in the presence of the additive controller gain perturbations.The non-fragile guaranteed cost controller can be obtained by solving a set of bilinear matrix inequalities（BMIs）.The Van de Vusse model is utilized to demonstrate the validity and effectiveness of the proposed approach.
基金Project(50721063) supported by the National Natural Science Foundation of China
文摘A novel discrete-time reaching law was proposed for uncertain discrete-time system,which contained process noise and measurement noise.The proposed method reserves all the advantages of discrete-time reaching law,which not only decreases the band width of sliding mode and strengthens the system robustness,but also improves the dynamic performance and stability capability of the system.Moreover,a discrete-time sliding mode control strategy based on Kalman filter method was designed,and Kalman filter was employed to eliminate the influence of system noise.Simulation results show that there is no chattering phenomenon in the output of controller and the state variables of controlled system,and the proposed algorithm is also feasible and has strong robustness to external disturbances.
基金supported by National Natural Science Foundation of China (Nos. 60974045 and 60674016)the Research Foundation of Education Bureau of Hunan Province, China (No. 08C090)
文摘This paper presents a novel design method for discrete-time repetitive control systems （RCS） based on two-dimensional （2D） discrete-time model. Firstly, the 2D model of an RCS is established by considering both the control action and the learning action in RCS. Then, through constructing a 2D state feedback controller, the design problem of the RCS is converted to the design problem of a 2D system. Then, using 2D system theory and linear matrix inequality （LMI） method, stability criterion is derived for the system without and with uncertainties, respectively. Parameters of the system can be determined by solving the LMI of the stability criterion. Finally, numerical simulations validate the effectiveness of the proposed method.
基金This work is supported by the National Natural Science Foundation of China (No.60421002) Priority supported financially by the New Century 151 Talent Project of Zhejiang Province.
文摘A new variable structure control algorithm based on sliding mode prediction for a class of discrete-time nonlinear systems is presented. By employing a special model to predict future sliding mode value, and combining feedback correction and receding horizon optimization methods which are extensively applied on predictive control strategy, a discrete-time variable structure control law is constructed. The closed-loop systems are proved to have robustness to uncertainties with unspecified boundaries. Numerical simulation and pendulum experiment results illustrate that the closed-loop systems possess desired performance, such as strong robustness, fast convergence and chattering elimination.
文摘This paper presents a distributed control protocol for consensus control of multi-agent systems(MASs) under external disturbances and network imperfections, including communication delay and random packet dropout. To comply with the discrete nature of networked systems, in contrast to most of the existing work for MASs under network imperfections,the agents are modeled by discrete-time dynamics. The communication network is considered to be undirected, its delay is considered to be time-varying but bounded, and its packet dropout is modeled by a Bernoulli distributed white sequence.Sufficient conditions in terms of linear matrix inequalities(LMIs)for asymptotic mean-square consensus stability are derived under network imperfections without considering external disturbances.A desired disturbance attenuation level in the presence of both external disturbances and network imperfections is also provided.A simulation example is given to verify the effectiveness of the proposed approach in coping with network imperfection and disturbances.
文摘The problem of designing fuzzy static output feedback controller for T-S discrete-time fuzzy bilinear system （DFBS） is presented. Based on parallel distribution compensation method, some sufficient conditions are derived to guarantee the stability of the overall fuzzy system. The stabilization conditions are further formulated into linear matrix inequality （LMI） so that the desired controller can be easily obtained by using the Matlab LMI toolbox. In comparison with the existing results, the drawbacks, such as coordinate transformation, same output matrices, have been elim- inated. Finally, a simulation example shows that the approach is effective.
文摘This paper develops a discrete-time sliding mode controller with a power rate exponential reaching law approach to enhance the performance of a pneumatic artificial muscle system in both reaching time and chattering reduction.The proposed method dynamically adapts to the variation of the switching function,which is based on an exponential term and a power rate term of the sliding surface.Thus,the controlled system can achieve high tracking performance while still obtain chattering-free control.Moreover,the effectiveness of the proposed method is validated through multiple experimental tests,focused on a dual pneumatic artificial muscle system.Finally,experimental results show the effectiveness of the proposed approach in this paper.
文摘Time-varying network induced delay in the communication channel severely affects the performance of closed loop network control systems. In this paper, a novel idea of compensating the fractional time varying communication delay in the sliding Surface is presented. The fractional time delay in the sensor to controller and controller to actuator channel is approximated using the Thiran approximation technique to design the sliding surface. A discrete-time sliding mode control law is derived using the proposed surface that compensates fractional time delay in sensor to controller and controller to actuator channels for uncertain network control systems. The sufficient condition for closed loop stability of the system is derived using the Lyapunov function. The efficacy of the proposed strategy is supported by the simulation results.
基金the National Natural Science Foundation of China (60574001)Program for New Century Excellent Talents in University (05-0485)Program for Innovative Research Team of Jiangnan University
文摘The robust reliable H∞ control problem for discrete-time Markovian jump systems with actuator failures is studied. A more practical model of actuator failures than outage is considered. Based on the state feedback method, the resulting closed-loop systems are reliable in that they remain robust stochastically stable and satisfy a certain level of H∞ disturbance attenuation not only when all actuators are operational, but also in case of some actuator failures, The solvability condition of controllers can be equivalent to a feasibility problem of coupled linear matrix inequalities （LMIs）. A numerical example is also given to illustrate the design procedures and their effectiveness.
基金supported by National Natural Science Foundation of China(61573200,61973175)the Fundamental Research Funds for the Central Universities,Nankai University(63201196)。
文摘Formation control of discrete-time linear multi-agent systems using directed switching topology is considered in this work via a reduced-order observer, in which a formation control protocol is proposed under the assumption that each directed communication topology has a directed spanning tree. By utilizing the relative outputs of neighboring agents, a reduced-order observer is designed for each following agent. A multi-step control algorithm is established based on the Lyapunov method and the modified discrete-time algebraic Riccati equation. A sufficient condition is given to ensure that the discrete-time linear multi-agent system can achieve the expected leader-following formation.Finally, numerical examples are provided so as to demonstrate the effectiveness of the obtained results.
