Supersonic Tailless Aerial Vehicles(STAVs)will become an essential force in Penetrating Counter Air(PCA),but STAVs do not have the traditional horizontal and vertical tails,making pitch and yaw control difficult.The a...Supersonic Tailless Aerial Vehicles(STAVs)will become an essential force in Penetrating Counter Air(PCA),but STAVs do not have the traditional horizontal and vertical tails,making pitch and yaw control difficult.The attack angle and the sideslip angle need to be limited to ensure that the engine inlet and the aerodynamic rudder at the rear of the vehicle can work properly,which is the so-called security constraints.In addition,the tracking error of the aerodynamic angle needs to be limited to achieve effective attitude control or high-accuracy tracking of trajectories,which is the so-called performance constraints.To this end,an attitude control method that meets the needs of PCA has been devised,based on constraint definition,coupled constraints handling,and control law design.Firstly,mathematical descriptions of the security constraints,performance constraints,and control constraints are given.Secondly,two treatment methods,coupled command filter and coupled funnel control are proposed for the aerodynamic angle coupled constraint problem.Finally,based on Nonlinear Dynamic Inverse(NDI)design,the coupled funnel controller is designed and validated by simulation for two typical mission scenarios,high-altitude penetration and low-altitude surprise defence.The proposed control method not only satisfies the security and performance constraints of STAV attitude control but also is highly robust.展开更多
To address the problem of high-performance trajectory tracking of a class of uncertain nonlinear systems,this paper proposes a novel proportional-integral-like funnel control(PI-like FC)strategy with rigorous theoreti...To address the problem of high-performance trajectory tracking of a class of uncertain nonlinear systems,this paper proposes a novel proportional-integral-like funnel control(PI-like FC)strategy with rigorous theoretical guarantees.The proposed method retains the prescribed transient performance capabilities inherent to funnel control while introducing an integral action to enhance steady-state accuracy.To mitigate the potential issue caused by integral action,aσ-modification mechanism is incorporated into the control design.The resulting PI-like funnel controller operates without requiring precise system models or detailed knowledge of the nonlinearities,thereby ensuring simplicity in design,ease of implementation,and broad applicability.Rigorous analysis establishes the closed-loop stability and guarantees that the tracking error remains strictly confined within predefined performance bounds.Simulation studies further validate the effectiveness and robustness of the proposed approach in achieving accurate trajectory tracking for uncertain nonlinear systems.展开更多
In this paper, a finite-time neural funnel control(FTNFC) scheme is proposed for motor servo systems with unknown input constraint. To deal with the non-smooth input saturation constraint problem, a smooth non-affine ...In this paper, a finite-time neural funnel control(FTNFC) scheme is proposed for motor servo systems with unknown input constraint. To deal with the non-smooth input saturation constraint problem, a smooth non-affine function of the control input signal is employed to approximate the saturation constraint, which is further transformed into an affine form according to the mean-value theorem. A fast terminal sliding mode manifold is constructed by using a novel funnel error variable to force the tracking error falling into a prescribe boundary within a finite time. Then, a simple sigmoid neural network is utilized to approximate the unknown system nonlinearity including the saturation.Different from the prescribed performance control(PPC), the proposed finite-time neural funnel control avoids using the inverse transformed function in the controller design, and could guarantee the prescribed tracking performance without knowing the saturation bounds in prior. The effectiveness and superior performance of the proposed method are verified by comparative simulation results.展开更多
This paper proposes a fault ride-through hybrid controller(FRTHC)for modular multi-level converter based high-voltage direct current(MMC-HVDC)transmission systems.The FRTHC comprises four loops of cascading switching ...This paper proposes a fault ride-through hybrid controller(FRTHC)for modular multi-level converter based high-voltage direct current(MMC-HVDC)transmission systems.The FRTHC comprises four loops of cascading switching control units(SCUs).Each SCU switches between a bang-bang funnel controller(BBFC)and proportional-integral(PI)control loop according to a state-dependent switching law.The BBFC can utilize the full control capability of each control loop using three-value control signals with the maximum available magnitude.A state-dependent switching law is designed for each SCU to guarantee its structural stability.Simulation studies are conducted to verify the superior fault ride-through capability of the MMC-HVDC transmission system controlled by FRTHC,in comparison to that controlled by a vector controller(VC)and a VC with DC voltage droop control(VDRC).展开更多
In this article, an unknown system dynamics estimator-based impedance control method is proposed for the lower limb exoskeleton to stimulate the tracking flexibility with the terminal target position when suffering pa...In this article, an unknown system dynamics estimator-based impedance control method is proposed for the lower limb exoskeleton to stimulate the tracking flexibility with the terminal target position when suffering parametric inaccuracies and unexpected disturbances. To reinforce the robust performance, via constructing the filtering operation-based dynamic relation, i.e., invariant manifold, the unknown system dynamics estimators are employed to maintain the accurate perturbation identification in both the hip and knee subsystem. Besides, a funnel control technique is designed to govern the convergence process within a minor overshoot and a higher steady-state precision. Meanwhile, an interactive complaint result can be obtained with the aid of the impedance control, where the prescribed terminal trajectory can be adjusted into the interaction variable-based target position by the force–position mapping, revealing the dynamic influence between the impedance coefficient (stiffness and damping) and the adjusted position magnitude. A sufficient stability analysis verifies the ultimately uniformly bounded results of all the error signals, and even the angle errors can be regulated within the predefined funnel boundary in the whole convergence. Finally, some simulations are provided to demonstrate the validity and superiority including the enhanced interaction flexibility and robustness.展开更多
In this paper, the multi-agent systems(MASs) typically with heterogeneous unknown nonlinearities and nonidentical unknown control coefficients are studied. Although the model information of MASs is coarse, the leader-...In this paper, the multi-agent systems(MASs) typically with heterogeneous unknown nonlinearities and nonidentical unknown control coefficients are studied. Although the model information of MASs is coarse, the leader-following consensus is still pursued, with a prescribed performance and zero consensus errors. Leveraging a powerful funnel control strategy, a fully distributed and completely relative-state-dependent protocol is designed. Distinctively, the time-varying function characterizing the performance boundary is introduced, not only to construct the funnel gains but also as an indispensable part of the protocol,enhancing the control ability and enabling the consensus errors to converge to zero(rather than a residual set). Remark that when control directions are unknown, coexisting with inherent system nonlinearities, it is essential to incorporate an additional compensation mechanism while imposing a hierarchical structure of communication topology for the control design and analysis. Simulation examples are given to illustrate the effectiveness of the theoretical results.展开更多
基金supported by the National Natural Science Foundation of China(No.62103439)the China Postdoctoral Science Foundation(No.2020M683716)+1 种基金the National Key Laboratory of Unmanned Aerial Vehicle Technology,Chinathe Youth Innovation Team of Shaanxi University,China.
文摘Supersonic Tailless Aerial Vehicles(STAVs)will become an essential force in Penetrating Counter Air(PCA),but STAVs do not have the traditional horizontal and vertical tails,making pitch and yaw control difficult.The attack angle and the sideslip angle need to be limited to ensure that the engine inlet and the aerodynamic rudder at the rear of the vehicle can work properly,which is the so-called security constraints.In addition,the tracking error of the aerodynamic angle needs to be limited to achieve effective attitude control or high-accuracy tracking of trajectories,which is the so-called performance constraints.To this end,an attitude control method that meets the needs of PCA has been devised,based on constraint definition,coupled constraints handling,and control law design.Firstly,mathematical descriptions of the security constraints,performance constraints,and control constraints are given.Secondly,two treatment methods,coupled command filter and coupled funnel control are proposed for the aerodynamic angle coupled constraint problem.Finally,based on Nonlinear Dynamic Inverse(NDI)design,the coupled funnel controller is designed and validated by simulation for two typical mission scenarios,high-altitude penetration and low-altitude surprise defence.The proposed control method not only satisfies the security and performance constraints of STAV attitude control but also is highly robust.
基金supported by the National Natural Science Foundation of China(Grant Nos.62173097,62121004,U2013601)the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2022A515011239,2024B1515120004)the Local Innovative and Research Team Project of Guangdong Special Support Program(Grant No.2019BT02X353)。
文摘To address the problem of high-performance trajectory tracking of a class of uncertain nonlinear systems,this paper proposes a novel proportional-integral-like funnel control(PI-like FC)strategy with rigorous theoretical guarantees.The proposed method retains the prescribed transient performance capabilities inherent to funnel control while introducing an integral action to enhance steady-state accuracy.To mitigate the potential issue caused by integral action,aσ-modification mechanism is incorporated into the control design.The resulting PI-like funnel controller operates without requiring precise system models or detailed knowledge of the nonlinearities,thereby ensuring simplicity in design,ease of implementation,and broad applicability.Rigorous analysis establishes the closed-loop stability and guarantees that the tracking error remains strictly confined within predefined performance bounds.Simulation studies further validate the effectiveness and robustness of the proposed approach in achieving accurate trajectory tracking for uncertain nonlinear systems.
基金supported by the National Natural Science Foundation of China under Grant Nos.61403343 and 61433003Zhejiang Provincial Natural Science Foundation of China under Grant No.Y17F030063the China Postdoctoral Science Foundation Funded Project under Grant No.2015M580521
文摘In this paper, a finite-time neural funnel control(FTNFC) scheme is proposed for motor servo systems with unknown input constraint. To deal with the non-smooth input saturation constraint problem, a smooth non-affine function of the control input signal is employed to approximate the saturation constraint, which is further transformed into an affine form according to the mean-value theorem. A fast terminal sliding mode manifold is constructed by using a novel funnel error variable to force the tracking error falling into a prescribe boundary within a finite time. Then, a simple sigmoid neural network is utilized to approximate the unknown system nonlinearity including the saturation.Different from the prescribed performance control(PPC), the proposed finite-time neural funnel control avoids using the inverse transformed function in the controller design, and could guarantee the prescribed tracking performance without knowing the saturation bounds in prior. The effectiveness and superior performance of the proposed method are verified by comparative simulation results.
基金supported in part by the State Key Program of National Natural Science Foundation of China (No.U1866210)Young Elite Scientists Sponsorship Program by CSEE (No.CSEE-YESS-2018007)Science and Technology Projects in Guangzhou (No.202102020221)。
文摘This paper proposes a fault ride-through hybrid controller(FRTHC)for modular multi-level converter based high-voltage direct current(MMC-HVDC)transmission systems.The FRTHC comprises four loops of cascading switching control units(SCUs).Each SCU switches between a bang-bang funnel controller(BBFC)and proportional-integral(PI)control loop according to a state-dependent switching law.The BBFC can utilize the full control capability of each control loop using three-value control signals with the maximum available magnitude.A state-dependent switching law is designed for each SCU to guarantee its structural stability.Simulation studies are conducted to verify the superior fault ride-through capability of the MMC-HVDC transmission system controlled by FRTHC,in comparison to that controlled by a vector controller(VC)and a VC with DC voltage droop control(VDRC).
基金Supported by National Natural Science Foundation of China(61403343)Scientific Research Foundation of the Education Department of Zhejiang Province,China(Y201329260)Natural Science Foundation of Zhejiang University of Technology(1301103053408)
基金supported in part by the Young Talent Fund of Association for Science and Technology in Shaanxi,China(No.20230126).
文摘In this article, an unknown system dynamics estimator-based impedance control method is proposed for the lower limb exoskeleton to stimulate the tracking flexibility with the terminal target position when suffering parametric inaccuracies and unexpected disturbances. To reinforce the robust performance, via constructing the filtering operation-based dynamic relation, i.e., invariant manifold, the unknown system dynamics estimators are employed to maintain the accurate perturbation identification in both the hip and knee subsystem. Besides, a funnel control technique is designed to govern the convergence process within a minor overshoot and a higher steady-state precision. Meanwhile, an interactive complaint result can be obtained with the aid of the impedance control, where the prescribed terminal trajectory can be adjusted into the interaction variable-based target position by the force–position mapping, revealing the dynamic influence between the impedance coefficient (stiffness and damping) and the adjusted position magnitude. A sufficient stability analysis verifies the ultimately uniformly bounded results of all the error signals, and even the angle errors can be regulated within the predefined funnel boundary in the whole convergence. Finally, some simulations are provided to demonstrate the validity and superiority including the enhanced interaction flexibility and robustness.
基金supported in part by the National Natural Science Foundation of China(61821004,62033007)Major Fundamental Research Program of Shandong Province(ZR2023ZD37)
文摘In this paper, the multi-agent systems(MASs) typically with heterogeneous unknown nonlinearities and nonidentical unknown control coefficients are studied. Although the model information of MASs is coarse, the leader-following consensus is still pursued, with a prescribed performance and zero consensus errors. Leveraging a powerful funnel control strategy, a fully distributed and completely relative-state-dependent protocol is designed. Distinctively, the time-varying function characterizing the performance boundary is introduced, not only to construct the funnel gains but also as an indispensable part of the protocol,enhancing the control ability and enabling the consensus errors to converge to zero(rather than a residual set). Remark that when control directions are unknown, coexisting with inherent system nonlinearities, it is essential to incorporate an additional compensation mechanism while imposing a hierarchical structure of communication topology for the control design and analysis. Simulation examples are given to illustrate the effectiveness of the theoretical results.
