Considering the challenges posed by external disturbances on carrier-based aircraft land-ing control,higher demands are required for the precision and convergence of the carrier landingcontrol system.First,this paper ...Considering the challenges posed by external disturbances on carrier-based aircraft land-ing control,higher demands are required for the precision and convergence of the carrier landingcontrol system.First,this paper proposes an Adaptive Terminal Sliding Combined Super TwistingControl(ATS-STC)method to address the issues of low precision,slow convergence,and poor dis-turbance rejection capability resulting from external disturbances,such as carrier air-wake and deckmotion.By introducing a nonlinear term into the sliding surface and employing an integralapproach,the proposed ATS-STC method can ensure finite-time convergence and mitigate the chat-tering problem.An adaptive law is also utilized to estimate the external disturbances,therebyenhancing the anti-disturbance performance.Then,the stability and convergence time analysis ofthe designed controller are conducted.Based on the proposed method,an Automatic Carrier Land-ing System(ACLS)is developed to perform the carrier landing control task.Furthermore,a multi-dimensional validation is carried out.For the numerical simulation test,the Terminal Sliding ModeControl(TSMC)method and Proportion Integration Differentiation(PID)method are introducedas comparison,the quantitative assessment results show that the tracking error of TSMC and PIDcan reach 1.5 times and 2 times that of the proposed method.Finally,the Hardware-in-the-Loop(HIL)test and real flight test are conducted.All the experimental results demonstrate that the pro-posed control method is more effective and precise.展开更多
In this paper, a sliding mode control with adaptive gain combined with a high-order sliding mode observer to solve the tracking problem for a quadrotor UAV is addressed, in presence of bounded external disturbances an...In this paper, a sliding mode control with adaptive gain combined with a high-order sliding mode observer to solve the tracking problem for a quadrotor UAV is addressed, in presence of bounded external disturbances and parametric uncertainties. The high order sliding mode observer is designed for estimating the linear and angular speed in order to implement the proposed scheme. Furthermore, a Lyapunov function is introduced to design the controller with the adaptation law, whereas an analysis of finite time convergence towards to zero is provided, where sufficient conditions are obtained. Regarding previous works from literature, one important advantage of proposed strategy is that the gains of control are parameterized in terms of only one adaptive parameter, which reduces the control effort by avoiding gain overestimation. Numerical simulations for tracking control of the quadrotor are given to show the performance of proposed adaptive control–observer scheme.展开更多
A relative position and attitude coupled sliding mode controller is proposed by combining the standard super twisting （ST） control and basic linear algorithm for autonomous rendezvous and docking. It is schemed for ...A relative position and attitude coupled sliding mode controller is proposed by combining the standard super twisting （ST） control and basic linear algorithm for autonomous rendezvous and docking. It is schemed for on-orbit servicing to a tumbling non- cooperative target spacecraft subjected to external disturbances. A coupled dynamic model is established including both kinemati- cal and dynamic coupled effect of relative rotation on relative translation, which illustrates the relative movement between the docking port located in target spacecraft and another in service spacecraft. The modified super twisting （MST） control algorithm containing linear compensation items is schemed to manipulate the relative position and attitude synchronously. The correction provides more robustness and convergence velocity for dealing with linearly growing perturbations than the ST control algorithm. Moreover, the stability characteristic of closed-loop system is ana- lyzed by Lyapunov method. Numerical simulations are adopted to verify the analysis with the comparison between MST and ST control algorithms. Simulation results demonstrate that the pro- posed MST controller is characterized by high precision, strong robustness and fast convergence velocity to attenuate the linearly increasing perturbations.展开更多
The path-following control design for an autonomous underwater vehicle(AUV)requires prior full or partial knowledge about the mathematical model defined through Newton’s second law based on a geometrical investigatio...The path-following control design for an autonomous underwater vehicle(AUV)requires prior full or partial knowledge about the mathematical model defined through Newton’s second law based on a geometrical investigation.AUV dynamics are highly nonlinear and time-varying,facing unpredictable disturbances due to AUVs operating in deep,hazardous oceanic environments.Consequently,navigation guidance and control systems for AUVs must learn and adapt to the time-varying dynamics of the nonlinear fully coupled vehicle model in the presence of highly unstructured underwater operating conditions.Many control engineers focus on the application of robust model-free adaptive control techniques in AUV maneuvers.Hence,the main goal is to design a novel salp swarm optimization of super twisting algorithm-based secondorder sliding mode controller for the planar path-following control of an AUV through regulation of the heading angle parameter.The finite time for tracking error convergence in the horizontal plane is provided through the control structure architecture,particularly for lateral deviations from the desired path.The proposed control law is designed such that it steers a robotic vehicle to track a predefined planar path at a constant speed determined by an end-user,without any temporal specification.Finally,the efficacy and tracking accuracy are evaluated through comparative analysis based on simulation and experimental hardware-in-loop assessment without violating the input constraints.Moreover,the proposed control law can handle parametric uncertainties and unpredictable disturbances such as ocean currents,wind,and measurement noise.展开更多
Designing a controller to stabilize maneuvering hovercrafts is an important challenge in amphibious vehicles.Hovercrafts are implemented in several applications,such as military missions,transportation,and scientific ...Designing a controller to stabilize maneuvering hovercrafts is an important challenge in amphibious vehicles.Hovercrafts are implemented in several applications,such as military missions,transportation,and scientific tasks.Thus.to improve their performance,it is crucial to control the system and compensate uncertainties and disruptions.In this paper,both classic and intelligent approaches are combined to design an observer-based controller.The system is assumed to be both controllable and observable.An adaptive neural network observer with guaranteed stability is derived for the nonlinear dynamics of a hovercraft,which is controlled via a nonsingular super-twisting terminal sliding-mode method.The main merits of the proposed method are as follows:(1) the Lyapunov stability of the overall closed-loop system,(2) the convergence of the tracking and observer errors to zero,(3) the robustness against uncertainties and disturbances,and(4) the reduction of the chattering phenomena.The simulation results validate the excellent performance of the derived method.展开更多
To enhance the robustness and dynamic performance of a self-excited induction generator (SEIG) used in a stand-alone wind energy system (WES), a virtual flux oriented control (VFOC) based on nonlinear super-twisting s...To enhance the robustness and dynamic performance of a self-excited induction generator (SEIG) used in a stand-alone wind energy system (WES), a virtual flux oriented control (VFOC) based on nonlinear super-twisting sliding mode control (STSMC) is adopted. STSMC is used to replace the conventional proportional-integral-Fuzzy Logic Controller (PI-FLC) of the inner current control loops. The combination of the proposed control strategy with space vector modulation (SVM) applied to a PWM rectifier brings many advantages such as reduction in harmonics, and precise and rapid tracking of the references. The performance of the proposed control technique (STSMC-VFOC-SVM) is verified through simulations and compared with the traditional technique (PI-FLC-VFOC-SVM). It shows that the proposed method improves the dynamics of the system with reduced current harmonics. In addition, the use of a virtual flux estimator instead of a phase-locked loop (PLL) eliminates the line voltage sensors and thus increases the reliability of the system.展开更多
This study addresses two issues about the interaction of the upper limb rehabilitation robot with individuals who have disabilities.The first step is to estimate the human's target position(also known as TPH).The ...This study addresses two issues about the interaction of the upper limb rehabilitation robot with individuals who have disabilities.The first step is to estimate the human's target position(also known as TPH).The second step is to develop a robust adaptive impedance control mechanism.A novel Non-singular Terminal Sliding Mode Control combined with an adaptive super-twisting controller is being developed to achieve this goal.This combination's purpose is to provide high reliability,continuous performance tracking of the system's trajectories.The proposed adaptive control strategy reduces matched dynamic uncertainty while also lowering chattering,which is the sliding mode's most glaring issue.The proposed TPH is coupled with adaptive impedance control with the use of a Radial Basis Function Neural Network,which allows a robotic exoskeleton to simply track the desired impedance model.To validate the approach in real-time,an exoskeleton robot was deployed in controlled experimental circumstances.A comparison study has been set up to show how the adaptive impedance approach proposed is better than other traditional controllers.展开更多
The aim of this study was to develop robust tracking control schemes for the 3D leap trajectory of hypersonic gliding vehicles using sliding mode theory. A predictor-corrector guidance method was applied to the genera...The aim of this study was to develop robust tracking control schemes for the 3D leap trajectory of hypersonic gliding vehicles using sliding mode theory. A predictor-corrector guidance method was applied to the generation of the reference trajectory, and drag acceleration was selected as the profile of reference tracking. A combined super-twisting sliding mode controller(CST-SMC) is proposed to decrease the tracking error and guarantee the tracking performance in the presence of system nonlinearities compared to three other common controllers: the linear sliding mode controller(L-SMC), global fast terminal sliding mode controller(GFT-SMC), and super-twisting sliding mode controller(ST-SMC). By using the developed controller, the system state of a second-order drag acceleration tracking error system can approach the global fast terminal sliding manifold in finite time. By using the Lyapunov approach, sufficient conditions are deduced to ensure that the tracking performance is obtained for a closed-loop system. Furthermore, we show that the controller is robust to initial uncertain parameters and other perturbations, as validated by simulation results with appropriate gains.展开更多
The non-cascade permanent magnet synchronous motor control system has the advantages of simple structure and less adjustable parameters,but the non-cascade structure needs to solve the problem of over-current protecti...The non-cascade permanent magnet synchronous motor control system has the advantages of simple structure and less adjustable parameters,but the non-cascade structure needs to solve the problem of over-current protection.In this paper,a current constrained control method is used to limit the starting current to a safe range.At the same time,to ensure the robustness and rapidity of the system,a super twist current constraint controller(CCSTA)is generated by combining super twist algorithm(STA)with current constraint control;Considering the diversity of internal and external disturbances,a functional disturbance observer(FDOB)is proposed to compensate the matched and unmatched disturbances,which further improves the robustness of the system.展开更多
Unmanned Aerial Vehicles(UAVs)are highly nonlinear and sophisticated systems that demand precise trajectory tracking in environments with uncertainties and disturbances.This research presents advanced nonlinear,adapti...Unmanned Aerial Vehicles(UAVs)are highly nonlinear and sophisticated systems that demand precise trajectory tracking in environments with uncertainties and disturbances.This research presents advanced nonlinear,adaptive,and artificial intelligence-based control strategies for UAVs.Beyond simulation,the strategies are experimentally evaluated on a coupled Two Degree of Freedom(2-DOF)Twin-rotor MIMO System(TRMS).The proposed strategies include Sliding Mode Control(SMC),Super Twisting(ST),Back Stepping(BS),and Neuro-Adaptive SMC(NNSMC),all designed using a feedback linearized mathematical model of the system.System performance is enhanced by decoupling the TRMS into horizontal and vertical subsystems through Lie derivatives and diffeomorphism principles.A Uniform Robust Exact Differentiator(URED)estimates rotor speeds and recovers missing derivatives,while a nonlinear state feedback observer improves system observability and mitigates uncertainties and external wind gusts.Furthermore,ST and NNSMC-based laws reduce high-frequency oscillations in the control input of the first-order SMC law,resulting in improved transient response.The experimental results reveal that NNSMC significantly outperforms ST and BS in terms of trajectory tracking accuracy,transient performance,and integral performance indices for both pitch and yaw angles.These findings underscore the superior convergence performance and robustness of NNSMC,establishing it as a promising solution for precise TRMS control in real real-world environment.展开更多
Purpose–The purpose of this paper is to design a robust control scheme to achieve robust tracking of velocity and altitude commands for a general hypersonic vehicle(HSV)in the presence of parameter variations and ext...Purpose–The purpose of this paper is to design a robust control scheme to achieve robust tracking of velocity and altitude commands for a general hypersonic vehicle(HSV)in the presence of parameter variations and external disturbances.Design/methodology/approach–The robust control scheme is composed of nonsingular terminal sliding mode control(NTSMC),super twisting control algorithm(STC)and recurrent neural network(RNN).First,by combing a novel NTSMC and STC algorithm,a second order NTSMC approach for HSV is proposed to provide fast,continuous and high precision tracking control.Second to relax the requirements for the bounds of the lumped uncertainties in control design,a RNN disturbance observer is presented to increase the robustness of the control system.The weights of RNN are updated by adaptive laws based on Lyapunov theorem,thus the closed-loop stability can be guaranteed.Findings–Simulation results demonstrate that the proposed method is effective,leading to promising performance.Originality/value–The main contributions of this work are:first,both parameter variations and external disturbances are considered in control design for the longitudinal dynamic model of HSV;and second,the proposed controller can remove chattering and achieve more favorable tracking performances than conventional sliding mode control.展开更多
基金supported by the National Natural Science Foundation of China(No.T2288101)the National Key Research and Development Project,China(No.2020YFC1512500)the Academic Excellence Foundation of Beijing University of Aeronautics and Astronautics(BUAA)。
文摘Considering the challenges posed by external disturbances on carrier-based aircraft land-ing control,higher demands are required for the precision and convergence of the carrier landingcontrol system.First,this paper proposes an Adaptive Terminal Sliding Combined Super TwistingControl(ATS-STC)method to address the issues of low precision,slow convergence,and poor dis-turbance rejection capability resulting from external disturbances,such as carrier air-wake and deckmotion.By introducing a nonlinear term into the sliding surface and employing an integralapproach,the proposed ATS-STC method can ensure finite-time convergence and mitigate the chat-tering problem.An adaptive law is also utilized to estimate the external disturbances,therebyenhancing the anti-disturbance performance.Then,the stability and convergence time analysis ofthe designed controller are conducted.Based on the proposed method,an Automatic Carrier Land-ing System(ACLS)is developed to perform the carrier landing control task.Furthermore,a multi-dimensional validation is carried out.For the numerical simulation test,the Terminal Sliding ModeControl(TSMC)method and Proportion Integration Differentiation(PID)method are introducedas comparison,the quantitative assessment results show that the tracking error of TSMC and PIDcan reach 1.5 times and 2 times that of the proposed method.Finally,the Hardware-in-the-Loop(HIL)test and real flight test are conducted.All the experimental results demonstrate that the pro-posed control method is more effective and precise.
文摘In this paper, a sliding mode control with adaptive gain combined with a high-order sliding mode observer to solve the tracking problem for a quadrotor UAV is addressed, in presence of bounded external disturbances and parametric uncertainties. The high order sliding mode observer is designed for estimating the linear and angular speed in order to implement the proposed scheme. Furthermore, a Lyapunov function is introduced to design the controller with the adaptation law, whereas an analysis of finite time convergence towards to zero is provided, where sufficient conditions are obtained. Regarding previous works from literature, one important advantage of proposed strategy is that the gains of control are parameterized in terms of only one adaptive parameter, which reduces the control effort by avoiding gain overestimation. Numerical simulations for tracking control of the quadrotor are given to show the performance of proposed adaptive control–observer scheme.
基金supported by the National Natural Science Foundation of China(61104026)
文摘A relative position and attitude coupled sliding mode controller is proposed by combining the standard super twisting （ST） control and basic linear algorithm for autonomous rendezvous and docking. It is schemed for on-orbit servicing to a tumbling non- cooperative target spacecraft subjected to external disturbances. A coupled dynamic model is established including both kinemati- cal and dynamic coupled effect of relative rotation on relative translation, which illustrates the relative movement between the docking port located in target spacecraft and another in service spacecraft. The modified super twisting （MST） control algorithm containing linear compensation items is schemed to manipulate the relative position and attitude synchronously. The correction provides more robustness and convergence velocity for dealing with linearly growing perturbations than the ST control algorithm. Moreover, the stability characteristic of closed-loop system is ana- lyzed by Lyapunov method. Numerical simulations are adopted to verify the analysis with the comparison between MST and ST control algorithms. Simulation results demonstrate that the pro- posed MST controller is characterized by high precision, strong robustness and fast convergence velocity to attenuate the linearly increasing perturbations.
文摘The path-following control design for an autonomous underwater vehicle(AUV)requires prior full or partial knowledge about the mathematical model defined through Newton’s second law based on a geometrical investigation.AUV dynamics are highly nonlinear and time-varying,facing unpredictable disturbances due to AUVs operating in deep,hazardous oceanic environments.Consequently,navigation guidance and control systems for AUVs must learn and adapt to the time-varying dynamics of the nonlinear fully coupled vehicle model in the presence of highly unstructured underwater operating conditions.Many control engineers focus on the application of robust model-free adaptive control techniques in AUV maneuvers.Hence,the main goal is to design a novel salp swarm optimization of super twisting algorithm-based secondorder sliding mode controller for the planar path-following control of an AUV through regulation of the heading angle parameter.The finite time for tracking error convergence in the horizontal plane is provided through the control structure architecture,particularly for lateral deviations from the desired path.The proposed control law is designed such that it steers a robotic vehicle to track a predefined planar path at a constant speed determined by an end-user,without any temporal specification.Finally,the efficacy and tracking accuracy are evaluated through comparative analysis based on simulation and experimental hardware-in-loop assessment without violating the input constraints.Moreover,the proposed control law can handle parametric uncertainties and unpredictable disturbances such as ocean currents,wind,and measurement noise.
文摘Designing a controller to stabilize maneuvering hovercrafts is an important challenge in amphibious vehicles.Hovercrafts are implemented in several applications,such as military missions,transportation,and scientific tasks.Thus.to improve their performance,it is crucial to control the system and compensate uncertainties and disruptions.In this paper,both classic and intelligent approaches are combined to design an observer-based controller.The system is assumed to be both controllable and observable.An adaptive neural network observer with guaranteed stability is derived for the nonlinear dynamics of a hovercraft,which is controlled via a nonsingular super-twisting terminal sliding-mode method.The main merits of the proposed method are as follows:(1) the Lyapunov stability of the overall closed-loop system,(2) the convergence of the tracking and observer errors to zero,(3) the robustness against uncertainties and disturbances,and(4) the reduction of the chattering phenomena.The simulation results validate the excellent performance of the derived method.
基金supported by the:Direction Générale de la Recherche Scientifique et du Développement Technologique(DGRSDT).
文摘To enhance the robustness and dynamic performance of a self-excited induction generator (SEIG) used in a stand-alone wind energy system (WES), a virtual flux oriented control (VFOC) based on nonlinear super-twisting sliding mode control (STSMC) is adopted. STSMC is used to replace the conventional proportional-integral-Fuzzy Logic Controller (PI-FLC) of the inner current control loops. The combination of the proposed control strategy with space vector modulation (SVM) applied to a PWM rectifier brings many advantages such as reduction in harmonics, and precise and rapid tracking of the references. The performance of the proposed control technique (STSMC-VFOC-SVM) is verified through simulations and compared with the traditional technique (PI-FLC-VFOC-SVM). It shows that the proposed method improves the dynamics of the system with reduced current harmonics. In addition, the use of a virtual flux estimator instead of a phase-locked loop (PLL) eliminates the line voltage sensors and thus increases the reliability of the system.
文摘This study addresses two issues about the interaction of the upper limb rehabilitation robot with individuals who have disabilities.The first step is to estimate the human's target position(also known as TPH).The second step is to develop a robust adaptive impedance control mechanism.A novel Non-singular Terminal Sliding Mode Control combined with an adaptive super-twisting controller is being developed to achieve this goal.This combination's purpose is to provide high reliability,continuous performance tracking of the system's trajectories.The proposed adaptive control strategy reduces matched dynamic uncertainty while also lowering chattering,which is the sliding mode's most glaring issue.The proposed TPH is coupled with adaptive impedance control with the use of a Radial Basis Function Neural Network,which allows a robotic exoskeleton to simply track the desired impedance model.To validate the approach in real-time,an exoskeleton robot was deployed in controlled experimental circumstances.A comparison study has been set up to show how the adaptive impedance approach proposed is better than other traditional controllers.
基金supported by the National Natural Science Foundation of China (No. 11972368)the Natural Science Foundation of Hunan Province (No. 2021JJ10045), China。
文摘The aim of this study was to develop robust tracking control schemes for the 3D leap trajectory of hypersonic gliding vehicles using sliding mode theory. A predictor-corrector guidance method was applied to the generation of the reference trajectory, and drag acceleration was selected as the profile of reference tracking. A combined super-twisting sliding mode controller(CST-SMC) is proposed to decrease the tracking error and guarantee the tracking performance in the presence of system nonlinearities compared to three other common controllers: the linear sliding mode controller(L-SMC), global fast terminal sliding mode controller(GFT-SMC), and super-twisting sliding mode controller(ST-SMC). By using the developed controller, the system state of a second-order drag acceleration tracking error system can approach the global fast terminal sliding manifold in finite time. By using the Lyapunov approach, sufficient conditions are deduced to ensure that the tracking performance is obtained for a closed-loop system. Furthermore, we show that the controller is robust to initial uncertain parameters and other perturbations, as validated by simulation results with appropriate gains.
基金This work was supported by the National Natural Science Foundation of China under Grant 61863023.
文摘The non-cascade permanent magnet synchronous motor control system has the advantages of simple structure and less adjustable parameters,but the non-cascade structure needs to solve the problem of over-current protection.In this paper,a current constrained control method is used to limit the starting current to a safe range.At the same time,to ensure the robustness and rapidity of the system,a super twist current constraint controller(CCSTA)is generated by combining super twist algorithm(STA)with current constraint control;Considering the diversity of internal and external disturbances,a functional disturbance observer(FDOB)is proposed to compensate the matched and unmatched disturbances,which further improves the robustness of the system.
基金supported by the National Natural Science Foundation of China(Grant No.12072027)the Key Research and Development Program of Henan Province(No.241111222000)the Henan Key Laboratory of General Aviation Technology(No.ZHKF-230201)
文摘Unmanned Aerial Vehicles(UAVs)are highly nonlinear and sophisticated systems that demand precise trajectory tracking in environments with uncertainties and disturbances.This research presents advanced nonlinear,adaptive,and artificial intelligence-based control strategies for UAVs.Beyond simulation,the strategies are experimentally evaluated on a coupled Two Degree of Freedom(2-DOF)Twin-rotor MIMO System(TRMS).The proposed strategies include Sliding Mode Control(SMC),Super Twisting(ST),Back Stepping(BS),and Neuro-Adaptive SMC(NNSMC),all designed using a feedback linearized mathematical model of the system.System performance is enhanced by decoupling the TRMS into horizontal and vertical subsystems through Lie derivatives and diffeomorphism principles.A Uniform Robust Exact Differentiator(URED)estimates rotor speeds and recovers missing derivatives,while a nonlinear state feedback observer improves system observability and mitigates uncertainties and external wind gusts.Furthermore,ST and NNSMC-based laws reduce high-frequency oscillations in the control input of the first-order SMC law,resulting in improved transient response.The experimental results reveal that NNSMC significantly outperforms ST and BS in terms of trajectory tracking accuracy,transient performance,and integral performance indices for both pitch and yaw angles.These findings underscore the superior convergence performance and robustness of NNSMC,establishing it as a promising solution for precise TRMS control in real real-world environment.
基金supported by the National Outstanding Youth Science Foundation(61125306)the National Natural Science Foundation of Major Research Plan(91016004).
文摘Purpose–The purpose of this paper is to design a robust control scheme to achieve robust tracking of velocity and altitude commands for a general hypersonic vehicle(HSV)in the presence of parameter variations and external disturbances.Design/methodology/approach–The robust control scheme is composed of nonsingular terminal sliding mode control(NTSMC),super twisting control algorithm(STC)and recurrent neural network(RNN).First,by combing a novel NTSMC and STC algorithm,a second order NTSMC approach for HSV is proposed to provide fast,continuous and high precision tracking control.Second to relax the requirements for the bounds of the lumped uncertainties in control design,a RNN disturbance observer is presented to increase the robustness of the control system.The weights of RNN are updated by adaptive laws based on Lyapunov theorem,thus the closed-loop stability can be guaranteed.Findings–Simulation results demonstrate that the proposed method is effective,leading to promising performance.Originality/value–The main contributions of this work are:first,both parameter variations and external disturbances are considered in control design for the longitudinal dynamic model of HSV;and second,the proposed controller can remove chattering and achieve more favorable tracking performances than conventional sliding mode control.
