In this work,a variable structure control(VSC)technique is proposed to achieve satisfactory robustness for unstable processes.Optimal values of unknown parameters of VSC are obtained using Whale optimization algorithm...In this work,a variable structure control(VSC)technique is proposed to achieve satisfactory robustness for unstable processes.Optimal values of unknown parameters of VSC are obtained using Whale optimization algorithm which was recently reported in literature.Stability analysis has been done to verify the suitability of the proposed structure for industrial processes.The proposed control strategy is applied to three different types of unstable processes including non-minimum phase and nonlinear systems.A comparative study ensures that the proposed scheme gives superior performance over the recently reported VSC system.Furthermore,the proposed method gives satisfactory results for a cart inverted pendulum system in the presence of external disturbance and noise.展开更多
Based on consideration of the differential relations between the immeasurable variables and measurable variables in electro-hydraulic servo system,adaptive dynamic recurrent fuzzy neural networks(ADRFNNs) were employe...Based on consideration of the differential relations between the immeasurable variables and measurable variables in electro-hydraulic servo system,adaptive dynamic recurrent fuzzy neural networks(ADRFNNs) were employed to identify the primary uncertainty and the mathematic model of the system was turned into an equivalent linear model with terms of secondary uncertainty.At the same time,gain adaptive sliding mode variable structure control(GASMVSC) was employed to synthesize the control effort.The results show that the unrealization problem caused by some system's immeasurable state variables in traditional fuzzy neural networks(TFNN) taking all state variables as its inputs is overcome.On the other hand,the identification by the ADRFNNs online with high accuracy and the adaptive function of the correction term's gain in the GASMVSC make the system possess strong robustness and improved steady accuracy,and the chattering phenomenon of the control effort is also suppressed effectively.展开更多
The problem of adaptive fuzzy control for a class of large-scale, time-delayed systems with unknown nonlinear dead-zone is discussed here. Based on the principle of variable structure control, a design scheme of adapt...The problem of adaptive fuzzy control for a class of large-scale, time-delayed systems with unknown nonlinear dead-zone is discussed here. Based on the principle of variable structure control, a design scheme of adaptive, decentralized, variable structure control is proposed. The approach removes the conditions that the dead-zone slopes and boundaries are equal and symmetric, respectively. In addition, it does not require that the assumptions that all parameters of the nonlinear dead-zone model and the lumped uncertainty are known constants. The adaptive compensation terms of the approximation errors axe adopted to minimize the influence of modeling errors and parameter estimation errors. By theoretical analysis, the closed-loop control system is proved to be semiglobally uniformly ultimately bounded, with tracking errors converging to zero. Simulation results demonstrate the effectiveness of the approach.展开更多
This paper, at the first time, considers the problem of decentralized variable structure control of complex giant singular uncertainty systems by using the property of diagonally dominant matrix and Frobenius-Person t...This paper, at the first time, considers the problem of decentralized variable structure control of complex giant singular uncertainty systems by using the property of diagonally dominant matrix and Frobenius-Person theorem. The splendid selection of switching manifold for each subsystem makes the design relatively straightforward and can be easily realized. An illustrate example is given.展开更多
A flight control system is designed for a reusable launch vehicle with aerodynamic control surfaces and reaction control system based on a variable-structure control and neural network theory.The control problems of c...A flight control system is designed for a reusable launch vehicle with aerodynamic control surfaces and reaction control system based on a variable-structure control and neural network theory.The control problems of coupling among the channels and the uncertainty of model parameters are solved by using the method.High precise and robust tracking of required attitude angles can be achieved in complicated air space.A mathematical model of reusable launch vehicle is presented first,and then a controller of flight system is presented.Base on the mathematical model,the controller is divided into two parts:variable-structure controller and neural network module which is used to modify the parameters of controller.This control system decouples the lateraldirectional tunnels well with a neural network sliding mode controller and provides a robust and de-coupled tracking for mission angle profiles.After this a control allocation algorithm is employed to allocate the torque moments to aerodynamic control surfaces and thrusters.The final simulation shows that the control system has a good accurate,robust and de-coupled tracking performance.The stable state error is less than 1°,and the overshoot is less than 5%.展开更多
This paper describes the important application of variable structure control (VSC) theory on induction motor (IM) decoupling control system. A design scheme using singular system variable structure control method for ...This paper describes the important application of variable structure control (VSC) theory on induction motor (IM) decoupling control system. A design scheme using singular system variable structure control method for a decoupling IM system is presented. The scheme is shown to be robust to parametric variations and external disturbances. Simulation results show the stability and effectiveness of the proposed scheme展开更多
The synchronization problem under two cases is considered. One is that the bound on the uncertainty existing in the controller is known, the other is that the bound is unknown. In the latter case, the simple adaptatio...The synchronization problem under two cases is considered. One is that the bound on the uncertainty existing in the controller is known, the other is that the bound is unknown. In the latter case, the simple adaptation laws for upper bound on the norm of the uncertainty is proposed. Using this adaptive upper bound, a variable structure control is designed. The proposed method does not guarantee the convergence of the adaptive upper bound to the real one but makes the system asymptotically stable.展开更多
A variable structure model reference adaptive control problem for the nonlinear system is studied in this paper. First, according to the relative degree concept of th nonlinear control system an error equation between...A variable structure model reference adaptive control problem for the nonlinear system is studied in this paper. First, according to the relative degree concept of th nonlinear control system an error equation between the outputs of the reference model and the controlled plant is derived. Then, by using the variable structrue control method, an algorithm of variable structure model reference adaptive control is deduced on the basis of a new concept of reaching law. The definition of the SISO system is introduced into the MIMO nonlinear system. Finally, as an example, a pendulum nonlinear control system is simulated to demonstrated the effectiveness of the method. The results show that the method has some advantages: the design is simple, intuitive and easy to be realized in engineering. Besides, it is of practical significance for the synthesis of nonlinear control systems.展开更多
The characteristics of surface maneuver targets are analyzed and a 3-D relative motion model for missiles and targets is established. A variable structure guidance law is designed considering the characteristics of ta...The characteristics of surface maneuver targets are analyzed and a 3-D relative motion model for missiles and targets is established. A variable structure guidance law is designed considering the characteristics of targets. In the guidance law, the distance between missiles and targets as well as the missile-target relative velocity are all substituted by estimation values. The estimation errors, the target＇s velocity, and the maneuver acceleration are all treated as bounded disturbance. The guidance law proposed can be implemented conveniently in engineering with little target information. The performance of the guidance system is analyzed theoretically and the numerical simulation result shows the effectiveness of the guidance law.展开更多
The problem of complete rejection of external inaccessible disturbances plays an important role in the modem control theory.Analysis and design of a control system with harmonic disturbances are challenging.This paper...The problem of complete rejection of external inaccessible disturbances plays an important role in the modem control theory.Analysis and design of a control system with harmonic disturbances are challenging.This paper present both linear and nonlinear harm onics observers for systems with harm onic disturbances.展开更多
An attitude control algorithm for reusable launch vehicle(RLV) in reentry phase is proposed based on sliding mode variable structure control technique.The aerodynamic characteristics of RLV vary rapidly,and the seriou...An attitude control algorithm for reusable launch vehicle(RLV) in reentry phase is proposed based on sliding mode variable structure control technique.The aerodynamic characteristics of RLV vary rapidly,and the serious uncertainties and nonlinearities exist in the reentry flight phase.As an example,American X-34 technology demonstrator is investigated.The chattering brought by the variable structure control technique is eliminated efficiently by choosing a suitable reaching law and a sign function.A control mode of reaction control system is presented based on the RCS scheme of X-34 vehicle.As two different attitude control effectors,aerosurfaces and RCS,are employed in the reentry flight phase,a composite control strategy based on the dynamic pressure variety is presented.Also,an actuator model and a RCS thruster model are built.Analysis and nonlinear simulation results show that the sliding mode variable structure controller achieves better performance,the overshoot and steady-state error are only 0.7% and 0.04° respectively.展开更多
文摘In this work,a variable structure control(VSC)technique is proposed to achieve satisfactory robustness for unstable processes.Optimal values of unknown parameters of VSC are obtained using Whale optimization algorithm which was recently reported in literature.Stability analysis has been done to verify the suitability of the proposed structure for industrial processes.The proposed control strategy is applied to three different types of unstable processes including non-minimum phase and nonlinear systems.A comparative study ensures that the proposed scheme gives superior performance over the recently reported VSC system.Furthermore,the proposed method gives satisfactory results for a cart inverted pendulum system in the presence of external disturbance and noise.
基金Project(60634020) supported by the National Natural Science Foundation of China
文摘Based on consideration of the differential relations between the immeasurable variables and measurable variables in electro-hydraulic servo system,adaptive dynamic recurrent fuzzy neural networks(ADRFNNs) were employed to identify the primary uncertainty and the mathematic model of the system was turned into an equivalent linear model with terms of secondary uncertainty.At the same time,gain adaptive sliding mode variable structure control(GASMVSC) was employed to synthesize the control effort.The results show that the unrealization problem caused by some system's immeasurable state variables in traditional fuzzy neural networks(TFNN) taking all state variables as its inputs is overcome.On the other hand,the identification by the ADRFNNs online with high accuracy and the adaptive function of the correction term's gain in the GASMVSC make the system possess strong robustness and improved steady accuracy,and the chattering phenomenon of the control effort is also suppressed effectively.
基金This project was supported by the National Natural Science Foundation of China (60074013)the Foundation of New Era Talent Engineering of Yangzhou University.
文摘The problem of adaptive fuzzy control for a class of large-scale, time-delayed systems with unknown nonlinear dead-zone is discussed here. Based on the principle of variable structure control, a design scheme of adaptive, decentralized, variable structure control is proposed. The approach removes the conditions that the dead-zone slopes and boundaries are equal and symmetric, respectively. In addition, it does not require that the assumptions that all parameters of the nonlinear dead-zone model and the lumped uncertainty are known constants. The adaptive compensation terms of the approximation errors axe adopted to minimize the influence of modeling errors and parameter estimation errors. By theoretical analysis, the closed-loop control system is proved to be semiglobally uniformly ultimately bounded, with tracking errors converging to zero. Simulation results demonstrate the effectiveness of the approach.
文摘This paper, at the first time, considers the problem of decentralized variable structure control of complex giant singular uncertainty systems by using the property of diagonally dominant matrix and Frobenius-Person theorem. The splendid selection of switching manifold for each subsystem makes the design relatively straightforward and can be easily realized. An illustrate example is given.
文摘A flight control system is designed for a reusable launch vehicle with aerodynamic control surfaces and reaction control system based on a variable-structure control and neural network theory.The control problems of coupling among the channels and the uncertainty of model parameters are solved by using the method.High precise and robust tracking of required attitude angles can be achieved in complicated air space.A mathematical model of reusable launch vehicle is presented first,and then a controller of flight system is presented.Base on the mathematical model,the controller is divided into two parts:variable-structure controller and neural network module which is used to modify the parameters of controller.This control system decouples the lateraldirectional tunnels well with a neural network sliding mode controller and provides a robust and de-coupled tracking for mission angle profiles.After this a control allocation algorithm is employed to allocate the torque moments to aerodynamic control surfaces and thrusters.The final simulation shows that the control system has a good accurate,robust and de-coupled tracking performance.The stable state error is less than 1°,and the overshoot is less than 5%.
文摘This paper describes the important application of variable structure control (VSC) theory on induction motor (IM) decoupling control system. A design scheme using singular system variable structure control method for a decoupling IM system is presented. The scheme is shown to be robust to parametric variations and external disturbances. Simulation results show the stability and effectiveness of the proposed scheme
文摘The synchronization problem under two cases is considered. One is that the bound on the uncertainty existing in the controller is known, the other is that the bound is unknown. In the latter case, the simple adaptation laws for upper bound on the norm of the uncertainty is proposed. Using this adaptive upper bound, a variable structure control is designed. The proposed method does not guarantee the convergence of the adaptive upper bound to the real one but makes the system asymptotically stable.
文摘A variable structure model reference adaptive control problem for the nonlinear system is studied in this paper. First, according to the relative degree concept of th nonlinear control system an error equation between the outputs of the reference model and the controlled plant is derived. Then, by using the variable structrue control method, an algorithm of variable structure model reference adaptive control is deduced on the basis of a new concept of reaching law. The definition of the SISO system is introduced into the MIMO nonlinear system. Finally, as an example, a pendulum nonlinear control system is simulated to demonstrated the effectiveness of the method. The results show that the method has some advantages: the design is simple, intuitive and easy to be realized in engineering. Besides, it is of practical significance for the synthesis of nonlinear control systems.
文摘The characteristics of surface maneuver targets are analyzed and a 3-D relative motion model for missiles and targets is established. A variable structure guidance law is designed considering the characteristics of targets. In the guidance law, the distance between missiles and targets as well as the missile-target relative velocity are all substituted by estimation values. The estimation errors, the target＇s velocity, and the maneuver acceleration are all treated as bounded disturbance. The guidance law proposed can be implemented conveniently in engineering with little target information. The performance of the guidance system is analyzed theoretically and the numerical simulation result shows the effectiveness of the guidance law.
文摘The problem of complete rejection of external inaccessible disturbances plays an important role in the modem control theory.Analysis and design of a control system with harmonic disturbances are challenging.This paper present both linear and nonlinear harm onics observers for systems with harm onic disturbances.
文摘An attitude control algorithm for reusable launch vehicle(RLV) in reentry phase is proposed based on sliding mode variable structure control technique.The aerodynamic characteristics of RLV vary rapidly,and the serious uncertainties and nonlinearities exist in the reentry flight phase.As an example,American X-34 technology demonstrator is investigated.The chattering brought by the variable structure control technique is eliminated efficiently by choosing a suitable reaching law and a sign function.A control mode of reaction control system is presented based on the RCS scheme of X-34 vehicle.As two different attitude control effectors,aerosurfaces and RCS,are employed in the reentry flight phase,a composite control strategy based on the dynamic pressure variety is presented.Also,an actuator model and a RCS thruster model are built.Analysis and nonlinear simulation results show that the sliding mode variable structure controller achieves better performance,the overshoot and steady-state error are only 0.7% and 0.04° respectively.
