This paper presents a nonlinear control approach to variable speed wind turbine(VSWT)with a wind speed estimator.The dynamics of the wind turbine(WT)is derived from single mass model.In this work,a modified Newton Rap...This paper presents a nonlinear control approach to variable speed wind turbine(VSWT)with a wind speed estimator.The dynamics of the wind turbine(WT)is derived from single mass model.In this work,a modified Newton Raphson estimator has been considered for exact estimation of effective wind speed.The main objective of this work is to extract maximum energy from the wind at below rated wind speed while reducing drive train oscillation.In order to achieve the above objectives,VSWT should operate close to the optimal power coefficient.The generator torque is considered as the control input to achieve maximum energy capture.From the literature,it is clear that existing linear and nonlinear control techniques suffer from poor tracking of WT dynamics,increased power loss and complex control law.In addition,they are not robust with respect to input disturbances.In order to overcome the above drawbacks,adaptive fuzzy integral sliding mode control(AFISMC)is proposed for VSWT control.The proposed controller is tested with different types of disturbances and compared with other nonlinear controllers such as sliding mode control and integral sliding mode control.The result shows the better performance of AFISMC and its robustness to input disturbances.In this paper,the discontinuity in integral sliding mode controller is smoothed by using hyperbolic tangent function,and the sliding gain is adapted using a fuzzy technique which makes the controller more robust.展开更多
The extraction of maximum power from the solar panels,using the sliding mode control scheme,becomes popular for partial weather atmospheric conditions due to its effective dynamic duty cycle ratio.However,the sliding ...The extraction of maximum power from the solar panels,using the sliding mode control scheme,becomes popular for partial weather atmospheric conditions due to its effective dynamic duty cycle ratio.However,the sliding mode control scheme was sophisticated with single integral and double integral sliding mode control scheme,which offer enhanced maximum power extraction and support enhanced solar panel efficiency in partial weather conditions.The operation of the sliding mode control scheme depends on the selection of a sliding surface selection based on the atmospheric weather condition,which enables the effective sliding duty cycle ratio operation for the DC/DC boost converter.The duty cycle ratio of the sliding mode control resembles the usual dynamic behavior to achieve enhanced efficiency compared to the various maximum power point tracking(MPPT)schemes.The major limitation of the sliding mode control scheme is to achieve the steady state voltage error of the solar panel in minimum settling time duration.The single integral sliding mode control scheme achieves the expected steady state voltage error limit but fails to achieve minimum settling time duration.Hence,the single integral sliding mode control is extended to a double integral sliding mode control scheme to achieve both steady state voltage error limits within the minimum settling time duration.This double integral sliding mode control scheme allows us to obtain the higher sliding surface duty cycle ratio which acts as the input signal to the boost converter.This activates the enhanced stable and reliable system operation,and nullifies the lacuna of maximum solar panel efficiency under partial weather conditions.Hence,this paper aims to present the design and performance operation of the double integral sliding mode(DISM)MPPT control scheme.To validate the performance analysis of the proposed DISM MPPT control scheme,the MATLAB/Simulink model is designed and verified.Also,the performance analysis of the proposed DISM MPPT control scheme is compared with展开更多
In the present work, through the path integral of Gaussian type correlation function, a new formalism based on Fermi-Golden Rule for calculating the rate constant of nonradiative decay process with Duschinsky rotation...In the present work, through the path integral of Gaussian type correlation function, a new formalism based on Fermi-Golden Rule for calculating the rate constant of nonradiative decay process with Duschinsky rotation effect in polyatomic molecules is developed. The advantage of the present path-integral formalism is promoting-mode free. In order to get the rate constant, a "transition rate matrix" needs to be calculated. The rate constant calculated previously is only an approximation of diagonal elements of our "transition rate matrix " . The total rate should be the summation over all the matrix elements.展开更多
This paper investigates interception missiles’trajectory tracking guidance problem under wind field and external disturbances in the boost phase.Indeed,the velocity control in such trajectory tracking guidance system...This paper investigates interception missiles’trajectory tracking guidance problem under wind field and external disturbances in the boost phase.Indeed,the velocity control in such trajectory tracking guidance systems of missiles is challenging.As our contribution,the velocity control channel is designed to deal with the intractable velocity problem and improve tracking accuracy.The global prescribed performance function,which guarantees the tracking error within the set range and the global convergence of the tracking guidance system,is first proposed based on the traditional PPF.Then,a tracking guidance strategy is derived using the integral sliding mode control techniques to make the sliding manifold and tracking errors converge to zero and avoid singularities.Meanwhile,an improved switching control law is introduced into the designed tracking guidance algorithm to deal with the chattering problem.A back propagation neural network(BPNN)extended state observer(BPNNESO)is employed in the inner loop to identify disturbances.The obtained results indicate that the proposed tracking guidance approach achieves the trajectory tracking guidance objective without and with disturbances and outperforms the existing tracking guidance schemes with the lowest tracking errors,convergence times,and overshoots.展开更多
The operation efficiency of the manipulator is placed in the primary position in automatic production. This paper proposes a coordinated control strategy for joint servo and visual servo to enable timely transfer and ...The operation efficiency of the manipulator is placed in the primary position in automatic production. This paper proposes a coordinated control strategy for joint servo and visual servo to enable timely transfer and accurate gripping in the working area. Aiming at the issues of chattering and slow convergence of traditional sliding mode controller, a fast variable power reaching rate on the basis of the non-singular fast terminal sliding mode controller is proposed, which can effectively reduce the convergence time and chattering. For the purpose of addressing the problem that the traditional visual servo control method is sensitive to the environment, a visual servo controller based on integral sliding mode is proposed, to ensure the favorable positioning accuracy of the manipulator. Based on the two proposed controllers mentioned above, a coordinated control strategy is used to implement the control of the manipulator. Finally, the upper computer software is developed using the C# programming language to monitor the workstation. The feasibility of the above-mentioned method is verified through multiple simulations and experiments.展开更多
In this paper,a Backstepping Global Integral Terminal Sliding Mode Controller(BGITSMC)with the view to enhancing the dynamic stability of a hybrid AC/DC microgrid has been presented.The proposed approach controls the ...In this paper,a Backstepping Global Integral Terminal Sliding Mode Controller(BGITSMC)with the view to enhancing the dynamic stability of a hybrid AC/DC microgrid has been presented.The proposed approach controls the switch-ing signals of the inverter,interlinking the DC-bus with the AC-bus in an AC/DC microgrid for a seamless interface and regulation of the output power of renewable energy sources(Solar Photovoltaic unit,PMSG-based wind farm),and Battery Energy Storage System.The proposed control approach guarantees the dynamic stability of a hybrid AC/DC microgrid by regulating the associated states of the microgrid system to their intended values.The dynamic stabil-ity of the microgrid system with the proposed control law has been proved using the Control Lyapunov Function.A simulation analysis was performed on a test hybrid AC/DC microgrid system to demonstrate the performance of the proposed control strategy in terms of maintaining power balance while the system’s operating point changed.Furthermore,the superiority of the proposed approach has been demonstrated by comparing its performance with the existing Sliding Mode Control(SMC)approach for a hybrid AC/DC microgrid.展开更多
With an aim to improve the transient stability of a DFIG wind farm penetrated multimachine power system(MPN),an adaptive fractional integral terminal sliding mode power control(AFITSMPC)strategy has been proposed for ...With an aim to improve the transient stability of a DFIG wind farm penetrated multimachine power system(MPN),an adaptive fractional integral terminal sliding mode power control(AFITSMPC)strategy has been proposed for the unified power flow controller(UPFC),which is compensating the MPN.The proposed AFITSMPC controls the dq-axis series injected voltage,which controls the admittance model(AM)of the UPFC.As a result the power output of the DFIG stabilizes which helps in maintaining the equilibrium between the electrical and mechanical power of the nearby generators.Subsequently the rotor angular deviation of the respective generators gets recovered,which significantly stabilizes the MPN.The proposed AFITSMPC for the admittance model of the UPFC has been validated in a DFIG wind farm penetrated 2 area 4 machine power system in the MATLAB environment.The robustness and efficacy of the proposed control strategy of the UPFC,in contrast to the conventional PI control is vindicated under a number of intrinsic operating conditions,and the results analyzed are satisfactory.展开更多
In this paper,an intelligent fractional-order integral sliding mode control(FOISMC)strategy based on an improved cascade observer is proposed.First,an FOISMC strategy is designed to control a permanent magnet synchron...In this paper,an intelligent fractional-order integral sliding mode control(FOISMC)strategy based on an improved cascade observer is proposed.First,an FOISMC strategy is designed to control a permanent magnet synchronous motor.It has good tracking performance,is strongly robust,and can effectively reduce chattering.The proposed FOISMC strategy associates strong points of the integral action(which can eliminate steady-state tracking errors)and the fractional calculus(which is flexible).Second,an improved cascade observer is proposed to detect the rotor information with a smaller observation error.The proposed observer combines an adaptive sliding mode observer and an extended high-gain observer.In addition,an improved variable-speed grey wolf optimization algorithm is designed to enhance controller parameters.The effectiveness of the strategy is tested using simulations and an experiment involving model uncertainty and external disturbance.展开更多
The electric fatigue load has a significant effect on the crack propagation behavior and failure life of piezoelectric materials and devices. In this paper, an electrical mixed-mode fatigue crack propagation model for...The electric fatigue load has a significant effect on the crack propagation behavior and failure life of piezoelectric materials and devices. In this paper, an electrical mixed-mode fatigue crack propagation model for piezoelectric materials is proposed based on the piezoelectric Jk-integral theory. The crack initiation, propagation, and life prediction criteria of piezoelectric materials under electric fatigue loading are given by this model, and the finite element simulation model is established to study the electrical mixed-mode crack propagation behavior of piezoelectric structures. Meanwhile, the electrical mixed-mode fatigue crack propagation model is applied to the fatigue crack propagation behavior of a piezoelectric typical defective structure, the crack–hole interference model. The mixed-mode crack propagation, fatigue life, and the interference behavior between the crack and hole at various hole locations of the crack–hole interference model are well recognized by this model. The crack propagation behavior under different electrical load intensities is also considered. The results show that the hole in front of the crack tip inhibits crack propagation to a certain extent, and the strength of electrical load affects the fatigue life of piezoelectric materials and structures. Therefore, the proposed electrical mixed-mode fatigue crack propagation model provides a reference for predicting the mixed-mode fatigue crack propagation behavior and fatigue life of piezoelectric structures under electric fatigue loading.展开更多
With the increasing precision of guidance,the impact of autopilot dynamic characteristics and target maneuvering abilities on precision guidance is becoming more and more significant.In order to reduce or even elimina...With the increasing precision of guidance,the impact of autopilot dynamic characteristics and target maneuvering abilities on precision guidance is becoming more and more significant.In order to reduce or even eliminate the autopilot dynamic operation and the target maneuvering influence,this paper suggests a guidance system model involving a novel integral sliding mode guidance law(ISMGL).The method utilizes the dynamic characteristics and the impact angle,combined with a sliding mode surface scheme that includes the desired line-ofsight angle,line-of-sight angular rate,and second-order differential of the angular line-of-sight.At the same time,the evaluation scenario considere the target maneuvering in the system as the external disturbance,and the non-homogeneous disturbance observer estimate the target maneuvering as a compensation of the guidance command.The proposed system’s stability is proven based on the Lyapunov stability criterion.The simulations reveale that ISMGL effectively intercepted large maneuvering targets and present a smaller miss-distance compared with traditional linear sliding mode guidance laws and trajectory shaping guidance laws.Furthermore,ISMGL has a more accurate impact angle and fast convergence speed.展开更多
文摘This paper presents a nonlinear control approach to variable speed wind turbine(VSWT)with a wind speed estimator.The dynamics of the wind turbine(WT)is derived from single mass model.In this work,a modified Newton Raphson estimator has been considered for exact estimation of effective wind speed.The main objective of this work is to extract maximum energy from the wind at below rated wind speed while reducing drive train oscillation.In order to achieve the above objectives,VSWT should operate close to the optimal power coefficient.The generator torque is considered as the control input to achieve maximum energy capture.From the literature,it is clear that existing linear and nonlinear control techniques suffer from poor tracking of WT dynamics,increased power loss and complex control law.In addition,they are not robust with respect to input disturbances.In order to overcome the above drawbacks,adaptive fuzzy integral sliding mode control(AFISMC)is proposed for VSWT control.The proposed controller is tested with different types of disturbances and compared with other nonlinear controllers such as sliding mode control and integral sliding mode control.The result shows the better performance of AFISMC and its robustness to input disturbances.In this paper,the discontinuity in integral sliding mode controller is smoothed by using hyperbolic tangent function,and the sliding gain is adapted using a fuzzy technique which makes the controller more robust.
文摘The extraction of maximum power from the solar panels,using the sliding mode control scheme,becomes popular for partial weather atmospheric conditions due to its effective dynamic duty cycle ratio.However,the sliding mode control scheme was sophisticated with single integral and double integral sliding mode control scheme,which offer enhanced maximum power extraction and support enhanced solar panel efficiency in partial weather conditions.The operation of the sliding mode control scheme depends on the selection of a sliding surface selection based on the atmospheric weather condition,which enables the effective sliding duty cycle ratio operation for the DC/DC boost converter.The duty cycle ratio of the sliding mode control resembles the usual dynamic behavior to achieve enhanced efficiency compared to the various maximum power point tracking(MPPT)schemes.The major limitation of the sliding mode control scheme is to achieve the steady state voltage error of the solar panel in minimum settling time duration.The single integral sliding mode control scheme achieves the expected steady state voltage error limit but fails to achieve minimum settling time duration.Hence,the single integral sliding mode control is extended to a double integral sliding mode control scheme to achieve both steady state voltage error limits within the minimum settling time duration.This double integral sliding mode control scheme allows us to obtain the higher sliding surface duty cycle ratio which acts as the input signal to the boost converter.This activates the enhanced stable and reliable system operation,and nullifies the lacuna of maximum solar panel efficiency under partial weather conditions.Hence,this paper aims to present the design and performance operation of the double integral sliding mode(DISM)MPPT control scheme.To validate the performance analysis of the proposed DISM MPPT control scheme,the MATLAB/Simulink model is designed and verified.Also,the performance analysis of the proposed DISM MPPT control scheme is compared with
基金Supported by the National Natural Science Foundation of China (Grant Nos. 10425420, 20433070 and 90503013)
文摘In the present work, through the path integral of Gaussian type correlation function, a new formalism based on Fermi-Golden Rule for calculating the rate constant of nonradiative decay process with Duschinsky rotation effect in polyatomic molecules is developed. The advantage of the present path-integral formalism is promoting-mode free. In order to get the rate constant, a "transition rate matrix" needs to be calculated. The rate constant calculated previously is only an approximation of diagonal elements of our "transition rate matrix " . The total rate should be the summation over all the matrix elements.
基金the National Natural Science Foundation of China(Grant No.12072090).
文摘This paper investigates interception missiles’trajectory tracking guidance problem under wind field and external disturbances in the boost phase.Indeed,the velocity control in such trajectory tracking guidance systems of missiles is challenging.As our contribution,the velocity control channel is designed to deal with the intractable velocity problem and improve tracking accuracy.The global prescribed performance function,which guarantees the tracking error within the set range and the global convergence of the tracking guidance system,is first proposed based on the traditional PPF.Then,a tracking guidance strategy is derived using the integral sliding mode control techniques to make the sliding manifold and tracking errors converge to zero and avoid singularities.Meanwhile,an improved switching control law is introduced into the designed tracking guidance algorithm to deal with the chattering problem.A back propagation neural network(BPNN)extended state observer(BPNNESO)is employed in the inner loop to identify disturbances.The obtained results indicate that the proposed tracking guidance approach achieves the trajectory tracking guidance objective without and with disturbances and outperforms the existing tracking guidance schemes with the lowest tracking errors,convergence times,and overshoots.
基金supported by the National Natural Science Foundation of China(No.62273189)the Natural Science Foundation of Shandong Province(No.ZR2021MF005).
文摘The operation efficiency of the manipulator is placed in the primary position in automatic production. This paper proposes a coordinated control strategy for joint servo and visual servo to enable timely transfer and accurate gripping in the working area. Aiming at the issues of chattering and slow convergence of traditional sliding mode controller, a fast variable power reaching rate on the basis of the non-singular fast terminal sliding mode controller is proposed, which can effectively reduce the convergence time and chattering. For the purpose of addressing the problem that the traditional visual servo control method is sensitive to the environment, a visual servo controller based on integral sliding mode is proposed, to ensure the favorable positioning accuracy of the manipulator. Based on the two proposed controllers mentioned above, a coordinated control strategy is used to implement the control of the manipulator. Finally, the upper computer software is developed using the C# programming language to monitor the workstation. The feasibility of the above-mentioned method is verified through multiple simulations and experiments.
文摘In this paper,a Backstepping Global Integral Terminal Sliding Mode Controller(BGITSMC)with the view to enhancing the dynamic stability of a hybrid AC/DC microgrid has been presented.The proposed approach controls the switch-ing signals of the inverter,interlinking the DC-bus with the AC-bus in an AC/DC microgrid for a seamless interface and regulation of the output power of renewable energy sources(Solar Photovoltaic unit,PMSG-based wind farm),and Battery Energy Storage System.The proposed control approach guarantees the dynamic stability of a hybrid AC/DC microgrid by regulating the associated states of the microgrid system to their intended values.The dynamic stabil-ity of the microgrid system with the proposed control law has been proved using the Control Lyapunov Function.A simulation analysis was performed on a test hybrid AC/DC microgrid system to demonstrate the performance of the proposed control strategy in terms of maintaining power balance while the system’s operating point changed.Furthermore,the superiority of the proposed approach has been demonstrated by comparing its performance with the existing Sliding Mode Control(SMC)approach for a hybrid AC/DC microgrid.
文摘With an aim to improve the transient stability of a DFIG wind farm penetrated multimachine power system(MPN),an adaptive fractional integral terminal sliding mode power control(AFITSMPC)strategy has been proposed for the unified power flow controller(UPFC),which is compensating the MPN.The proposed AFITSMPC controls the dq-axis series injected voltage,which controls the admittance model(AM)of the UPFC.As a result the power output of the DFIG stabilizes which helps in maintaining the equilibrium between the electrical and mechanical power of the nearby generators.Subsequently the rotor angular deviation of the respective generators gets recovered,which significantly stabilizes the MPN.The proposed AFITSMPC for the admittance model of the UPFC has been validated in a DFIG wind farm penetrated 2 area 4 machine power system in the MATLAB environment.The robustness and efficacy of the proposed control strategy of the UPFC,in contrast to the conventional PI control is vindicated under a number of intrinsic operating conditions,and the results analyzed are satisfactory.
基金supported by the National Natural Science Foundation of China(No.51876089)the Open Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems,China(No.GZKF-202005)。
文摘In this paper,an intelligent fractional-order integral sliding mode control(FOISMC)strategy based on an improved cascade observer is proposed.First,an FOISMC strategy is designed to control a permanent magnet synchronous motor.It has good tracking performance,is strongly robust,and can effectively reduce chattering.The proposed FOISMC strategy associates strong points of the integral action(which can eliminate steady-state tracking errors)and the fractional calculus(which is flexible).Second,an improved cascade observer is proposed to detect the rotor information with a smaller observation error.The proposed observer combines an adaptive sliding mode observer and an extended high-gain observer.In addition,an improved variable-speed grey wolf optimization algorithm is designed to enhance controller parameters.The effectiveness of the strategy is tested using simulations and an experiment involving model uncertainty and external disturbance.
基金supported by the National Natural Science Foundation of China(No.12172270)the Fundamental Research Funds for the Central Universities in China.
文摘The electric fatigue load has a significant effect on the crack propagation behavior and failure life of piezoelectric materials and devices. In this paper, an electrical mixed-mode fatigue crack propagation model for piezoelectric materials is proposed based on the piezoelectric Jk-integral theory. The crack initiation, propagation, and life prediction criteria of piezoelectric materials under electric fatigue loading are given by this model, and the finite element simulation model is established to study the electrical mixed-mode crack propagation behavior of piezoelectric structures. Meanwhile, the electrical mixed-mode fatigue crack propagation model is applied to the fatigue crack propagation behavior of a piezoelectric typical defective structure, the crack–hole interference model. The mixed-mode crack propagation, fatigue life, and the interference behavior between the crack and hole at various hole locations of the crack–hole interference model are well recognized by this model. The crack propagation behavior under different electrical load intensities is also considered. The results show that the hole in front of the crack tip inhibits crack propagation to a certain extent, and the strength of electrical load affects the fatigue life of piezoelectric materials and structures. Therefore, the proposed electrical mixed-mode fatigue crack propagation model provides a reference for predicting the mixed-mode fatigue crack propagation behavior and fatigue life of piezoelectric structures under electric fatigue loading.
文摘With the increasing precision of guidance,the impact of autopilot dynamic characteristics and target maneuvering abilities on precision guidance is becoming more and more significant.In order to reduce or even eliminate the autopilot dynamic operation and the target maneuvering influence,this paper suggests a guidance system model involving a novel integral sliding mode guidance law(ISMGL).The method utilizes the dynamic characteristics and the impact angle,combined with a sliding mode surface scheme that includes the desired line-ofsight angle,line-of-sight angular rate,and second-order differential of the angular line-of-sight.At the same time,the evaluation scenario considere the target maneuvering in the system as the external disturbance,and the non-homogeneous disturbance observer estimate the target maneuvering as a compensation of the guidance command.The proposed system’s stability is proven based on the Lyapunov stability criterion.The simulations reveale that ISMGL effectively intercepted large maneuvering targets and present a smaller miss-distance compared with traditional linear sliding mode guidance laws and trajectory shaping guidance laws.Furthermore,ISMGL has a more accurate impact angle and fast convergence speed.
