To elucidate the fracturing mechanism of deep hard rock under complex disturbance environments,this study investigates the dynamic failure behavior of pre-damaged granite subjected to multi-source dynamic disturbances...To elucidate the fracturing mechanism of deep hard rock under complex disturbance environments,this study investigates the dynamic failure behavior of pre-damaged granite subjected to multi-source dynamic disturbances.Blasting vibration monitoring was conducted in a deep-buried drill-and-blast tunnel to characterize in-situ dynamic loading conditions.Subsequently,true triaxial compression tests incorporating multi-source disturbances were performed using a self-developed wide-low-frequency true triaxial system to simulate disturbance accumulation and damage evolution in granite.The results demonstrate that combined dynamic disturbances and unloading damage significantly accelerate strength degradation and trigger shear-slip failure along preferentially oriented blast-induced fractures,with strength reductions up to 16.7%.Layered failure was observed on the free surface of pre-damaged granite under biaxial loading,indicating a disturbance-induced fracture localization mechanism.Time-stress-fracture-energy coupling fields were constructed to reveal the spatiotemporal characteristics of fracture evolution.Critical precursor frequency bands(105-150,185-225,and 300-325 kHz)were identified,which serve as diagnostic signatures of impending failure.A dynamic instability mechanism driven by multi-source disturbance superposition and pre-damage evolution was established.Furthermore,a grouting-based wave-absorption control strategy was proposed to mitigate deep dynamic disasters by attenuating disturbance amplitude and reducing excitation frequency.展开更多
During bipedal walking,it is critical to detect and adjust the robot postures by feedback control to maintain its normal state amidst multi-source random disturbances arising from some unavoidable uncertain factors.Th...During bipedal walking,it is critical to detect and adjust the robot postures by feedback control to maintain its normal state amidst multi-source random disturbances arising from some unavoidable uncertain factors.The radical basis function（RBF）neural network model of a five-link biped robot is established,and two certain disturbances and a randomly uncertain disturbance are then mixed with the optimal torques in the network model to study the performance of the biped robot by several evaluation indices and a specific Poincar′e map.In contrast with the simulations,the response varies as desired under optimal inputting while the output is fluctuating in the situation of disturbance driving.Simulation results from noise inputting also show that the dynamics of the robot is less sensitive to the disturbance of knee joint input of the swing leg than those of the other three joints,the response errors of the biped will be increasing with higher disturbance levels,and especially there are larger output fluctuations in the knee and hip joints of the swing leg.展开更多
A new method of single sample polarization filtering is proposed. The algorithm is fast and suitable for the polarization processing of stationary or nonstationary polarized disturbed signals with one or more independ...A new method of single sample polarization filtering is proposed. The algorithm is fast and suitable for the polarization processing of stationary or nonstationary polarized disturbed signals with one or more independent disturbances. A ground wave polarimetric radar with the ability of radio disturbance suppresion is then introduced. Some numerical results demonstrate the effectiveness of single sample polarization filtering method for ground wave polarimetric radar.展开更多
The rolling mill vibration not only seriously causes the strip thickness heterogeneity, but also damages the rolling mill equipment and its electrical components. Existing vibration suppression methods are passive and...The rolling mill vibration not only seriously causes the strip thickness heterogeneity, but also damages the rolling mill equipment and its electrical components. Existing vibration suppression methods are passive and mainly tune mechanical, hydraulic, electrical and rolling process parameters. A new active vibration suppression method was thus proposed using the disturbance estimation and compensation algorithm. Firstly, the hydraulic-mechanical coupling model of the rolling mill vibration was established, and an active vibration suppressor was designed based on the extended state observer. Then, through the numerical simulation, it is found that the vibration energy is reduced by 35.3% using the vibration suppressor, and the vibration suppressor is valid when the vibration frequency is lower than 60 Hz Finally, the vibration suppressor was applied to the in-site manufacturing, and the expected vibration suppression was obtained. The method makes the produced steel strip have more uniform thickness and further significantly increases the finished product ratio.展开更多
A composite anti-disturbance predictive control strategy employing a Multi-dimensional Taylor Network(MTN)is presented for unmanned systems subject to time-delay and multi-source disturbances.First,the multi-source di...A composite anti-disturbance predictive control strategy employing a Multi-dimensional Taylor Network(MTN)is presented for unmanned systems subject to time-delay and multi-source disturbances.First,the multi-source disturbances are addressed according to their specific characteristics as follows:(A)an MTN data-driven model,which is used for uncertainty description,is designed accompanied with the mechanism model to represent the unmanned systems;(B)an adaptive MTN filter is used to remove the influence of the internal disturbance;(C)an MTN disturbance observer is constructed to estimate and compensate for the influence of the external disturbance;(D)the Extended Kalman Filter(EKF)algorithm is utilized as the learning mechanism for MTNs.Second,to address the time-delay effect,a recursiveτstep-ahead MTN predictive model is designed utilizing recursive technology,aiming to mitigate the impact of time-delay,and the EKF algorithm is employed as its learning mechanism.Then,the MTN predictive control law is designed based on the quadratic performance index.By implementing the proposed composite controller to unmanned systems,simultaneous feedforward compensation and feedback suppression to the multi-source disturbances are conducted.Finally,the convergence of the MTN and the stability of the closed-loop system are established utilizing the Lyapunov theorem.Two exemplary applications of unmanned systems involving unmanned vehicle and rigid spacecraft are presented to validate the effectiveness of the proposed approach.展开更多
An experimental investigation on the disturbance effect of jet-type active vibration suppression device on vortexinduced vibration of deep-sea riser was carried out in the wave-flow combined flume.The vibration suppre...An experimental investigation on the disturbance effect of jet-type active vibration suppression device on vortexinduced vibration of deep-sea riser was carried out in the wave-flow combined flume.The vibration suppression device was designed in which the jet pipe was horizontally fixed to the front end of the riser.By varying three different excitation spacings and multi-stage outflow velocities,the influence law of the dominant frequency,dimensionless displacement and other dynamic response parameters was studied under different excitation spacings,and the mechanism and sensitive characteristics of the disturbance suppression were explored.The results indicate that the variation of excitation spacing makes gas curtain enter the strong disturbed flow region at different velocities and angles,and the coupling relationship between excitation spacing and reduced velocity is the key factor to enter the strong disturbed flow region to achieve the optimal disturbance suppression.In the strong disturbed flow region,the influence of gas curtain on the dominant frequency is obviously affected by the flow velocity,while the vibration displacement is stable at the same amplitude and is weakly affected by the flow velocity.Gas curtain can effectively disturb the formation of vortex shedding,destroy the strong nonlinear coupled vibration of the riser,and achieve better vibration suppression effect.In the weak disturbed flow region,the vortex length of the riser tail is prolonged,the strong nonlinear coupled vibration of the riser is gradually restored,and the vibration suppression effect of the device gradually decreases.展开更多
This paper investigates the high-performance control issues of systems affected by time-varying disturbances and measurement noise.Conventionally,active disturbance rejection control(ADRC)is a favorable control strate...This paper investigates the high-performance control issues of systems affected by time-varying disturbances and measurement noise.Conventionally,active disturbance rejection control(ADRC)is a favorable control strategy to reject unknown disturbances and uncertainties.However,its control performance is limited because standard extended state observer(ESO)struggles to effectively estimate time-varying disturbances.The emergence of high-order ESO(HESO)alleviates the limitation.Unfortunately,it deteriorates the noise suppression capability when the disturbance rejection is enhanced.To tackle this challenge,an improved ADRC with cascade HESO(CHESO)is proposed.A comprehensive theoretical analysis associated with the performance of HESO is given for the first time.The presented analyses provide an intuitive understanding of the performance of HESO.Then,a novel CHESO is developed.The convergence of CHESO is proved via input-to-state stable theory.Extensive frequency domain analyses indicate that CHESO has stronger disturbance rejection and high-frequency noise attenuation performance than ESO and HESO without increasing the observer bandwidth.Comparative simulations conducted on a servo control system validate the effectiveness and preponderance of the proposed method.展开更多
In order to enhance the dynamic control precision of inertial stabilization platform(ISP),a disturbance sliding mode observer(DSMO)is proposed in this paper suppressing disturbance torques inherent within the system.T...In order to enhance the dynamic control precision of inertial stabilization platform(ISP),a disturbance sliding mode observer(DSMO)is proposed in this paper suppressing disturbance torques inherent within the system.The control accuracy of ISP is fundamentally circumscribed by various disturbance torques in rotating shaft.Therefore,a dynamic model of ISP incorporating composite perturbations is established with regard to the stabilization of axis in the inertial reference frame.Subsequently,an online estimator for control loop uncertainties based on the sliding mode control algorithm is designed to estimate the aggregate disturbances of various parameters uncertainties and other unmodeled disturbances that cannot be accurately calibrated.Finally,the proposed DSMO is integrated into a classical proportional-integral-derivative(PID)control scheme,utilizing feedforward approach to compensate the composite disturbance in the control loop online.The effectiveness of the proposed disturbance observer is validated through simulation and hardware experimentation,demonstrating a significant improvement in the dynamic control performance and robustness of the classical PID controller extensively utilized in the field of engineering.展开更多
This article investigates the anti-disturbance and stabilization problems for the nonlinear uncertain permanent magnet synchronous motor(PMSM)with stator voltage saturation and unknown load.A smooth switching mechanis...This article investigates the anti-disturbance and stabilization problems for the nonlinear uncertain permanent magnet synchronous motor(PMSM)with stator voltage saturation and unknown load.A smooth switching mechanism is presented to structure the adaptive integral terminal sliding mode control(SMC)strategy.The control design consists of compensation control and nominal control,which improves the rapidity and accuracy of trajectory tracking.The smooth saturation model based on the error function is applied to approximate the voltage saturation phenomenon.Additionally,to deal with the adverse effects of various unknown disturbances,including model parameter uncertainties and unknown external load disturbances,an improved disturbance observer(DO)is proposed.This observer effectively suppresses the fluctuations caused by fixed gain during the starting period of the system.Finally,the experimental results under different conditions show that the proposed strategy has good tracking and disturbance suppression performances.展开更多
During the startup of the hydraulic turbine generators,the hybrid magnetic bearing support system exhibits displacement fluctuations,and the nonlinearity and strong coupling characteristics of the magnetic bearings li...During the startup of the hydraulic turbine generators,the hybrid magnetic bearing support system exhibits displacement fluctuations,and the nonlinearity and strong coupling characteristics of the magnetic bearings limit the accuracy of rotor modeling,making traditional control methods difficult to adapt to parameter variations.To suppress startup disturbances and achieve a control strategy with low computational complexity and high precision,this paper proposes a five-degree-of-freedom hybrid magnetic bearing control strategy based on an improved cascaded reduced-order linear active disturbance rejection controller(CRLADRC).The front-stage reduced-order linear extended state observer(FRLESO)reduces the system’s computational complexity,enabling the system to maintain stability during motor startup disturbances.The second-stage reduced-order linear extended state observer(SRLESO)further enhances the system’s disturbance estimation accuracy while maintaining low computational complexity.Furthermore,the disturbance rejection and noise suppression capabilities are analyzed in the frequency domain and the stability of the proposed control method is proven using Lyapunov theory.Experimental results indicate that the proposed strategy effectively reduces displacement fluctuations in the hybrid magnetic bearing support system during motor startup,significantly enhancing the system’s robustness.展开更多
To solve the synchronization and tracking problems,a cooperative control scheme is proposed for a class of higher-order multi-input and multi-output(MIMO)nonlinear multi-agent systems(MASs)subjected to uncertainties a...To solve the synchronization and tracking problems,a cooperative control scheme is proposed for a class of higher-order multi-input and multi-output(MIMO)nonlinear multi-agent systems(MASs)subjected to uncertainties and external disturbances.First,coupled relationships among Laplace matrix,leader-following adjacency matrix and consensus error are analyzed based on undirected graph.Furthermore,nonlinear disturbance observers(NDOs)are designed to estimate compounded disturbances in MASs,and a distributed cooperative anti-disturbance control protocol is proposed for high-order MIMO nonlinear MASs based on the outputs of NDOs and dynamic surface control approach.Finally,the feasibility and effectiveness of the proposed scheme are proven based on Lyapunov stability theory and simulation experiments.展开更多
The high penetration of renewable energy has led to the widespread emergence of weak grids,under which grid-following(GFL)inverters suffer from dynamic instability induced by phase-locked loops(PLL).Although reducing ...The high penetration of renewable energy has led to the widespread emergence of weak grids,under which grid-following(GFL)inverters suffer from dynamic instability induced by phase-locked loops(PLL).Although reducing the bandwidth of the PLL can enhance system stability,it significantly degrades the ability of the inverter to reject power interaction disturbances.The inherent trade-off between the bandwidth of the PLL and its disturbance suppression capability are investigated.A cooperative strategy through a grid-forming(GFM)inverter to improve the robustness of GFL inverters without requiring hardware modifications is introduced.The simulation results validate that the proposed strategy effectively suppresses power interaction disturbances and enhances system stability under weak-grid scenarios.展开更多
Current research on active flutter suppression considering time delays tends to focus on fixed time delays.To address situations where the control loop may experience time-varying delays with uncertainty,a time-varyin...Current research on active flutter suppression considering time delays tends to focus on fixed time delays.To address situations where the control loop may experience time-varying delays with uncertainty,a time-varying-delay Active Disturbance Rejection Control(TVD-ADRC)is proposed.First,a parameterized unsteady aerodynamic reduced-order model(ROM)based on a long short-term memory network is introduced into the aeroservoelastic modeling.This model is applied to predict unsteady aerodynamic forces and aeroservoelastic(ASE)behaviors across a wide range of Mach numbers.Its effectiveness in capturing the characteristics of unsteady aerodynamics is validated through comparisons with the high-fid elity computational fluid dynamics(CFD)simulations.Second,the proposed method integrates ADRC with a delayed input and a time-d elay identification module in the controller design.Specifically,the timevarying delay is identified using the cross-correlation function method with a moving window,and this method dynamically updates the time-delay compensation module.Additionally,a genetic algorithm is employed to optimize controller parameters,and the integral of the time-weighted absolute error is selected as the performance evaluation index for the control system.Finally,a three-degree-of-freedom aeroservoelastic system of an airfoil with a trailing-edge control surface is studied for flutter suppression.Flutter control under uncertain time-varying delays during flutter occurrence is investigated,and the impact of the magnitude of the time delay on the effectiveness of the flutter control is analyzed.Simulation results indicate that the proposed TVDADRC controller could effectively suppress the aeroelastic instabilities across a wide range of Mach numbers and effectively counteract the negative effects of time-varying delays.展开更多
A modified four-dimensional linear active disturbance rejection control(LADRC)strategy is proposed for a dual three-phase permanent magnet synchronous generator(DTP-PMSG)system to reduce cross-coupling between the d a...A modified four-dimensional linear active disturbance rejection control(LADRC)strategy is proposed for a dual three-phase permanent magnet synchronous generator(DTP-PMSG)system to reduce cross-coupling between the d and q axis currents in the d-q subspace and harmonic currents in the x-y subspace.In the d-q subspace,the proposed strategy uses a model-based LADRC to enhance the decoupling effect between the d and q axes and the disturbance rejection ability against parameter variation.In the x-y subspace,the 5th and 7th harmonic current suppression abilities are improved by using quasi-resonant units parallel to the extended state observer of the traditional LADRC.The proposed modified LADRC strategy improved both the steady-state performance and dynamic response of the DTP-PMSG system.The experimental results demonstrate that the proposed strategy is both feasible and effective.展开更多
针对四旋翼无人机吊挂系统的负载摆动抑制和轨迹跟踪问题,提出一种线性自抗扰控制器(Liner Active Disturbance Rejection Controller,LADRC)的轨迹跟踪控制方法。首先,考虑到四旋翼吊挂负载耦合飞行的未知外界扰动与模型的动态不确定性...针对四旋翼无人机吊挂系统的负载摆动抑制和轨迹跟踪问题,提出一种线性自抗扰控制器(Liner Active Disturbance Rejection Controller,LADRC)的轨迹跟踪控制方法。首先,考虑到四旋翼吊挂负载耦合飞行的未知外界扰动与模型的动态不确定性,为飞行器的姿态、位置设计线性自抗扰控制器,通过扩张状态观测器(Extended State Observer,ESO)观测负载摆动和环境干扰对机体的扰动,并对控制量进行相应补偿,来抑制外界和负载摆动给机体带来的干扰,保证无人机飞行过程中的稳定性。其次,针对四旋翼无人机吊挂系统在飞行过程中负载摆角过大的问题,设计加速度规划摆角抑制算法,通过摆角的实时反馈对四旋翼无人机的位置轨迹输入进行路径规划,实现飞行过程中负载摆动的抑制。最后,通过仿真结果证明该控制方法对飞行器的位置及姿态控制效果较好,同时验证了所提的轨迹规划方法能够有效抑制吊挂物的摆动,且对干扰的鲁棒性较强。展开更多
基金supported by the National Key R&D Program of China(No.2023YFB2603602)the National Natural Science Foundation of China(Nos.52222810 and 52178383).
文摘To elucidate the fracturing mechanism of deep hard rock under complex disturbance environments,this study investigates the dynamic failure behavior of pre-damaged granite subjected to multi-source dynamic disturbances.Blasting vibration monitoring was conducted in a deep-buried drill-and-blast tunnel to characterize in-situ dynamic loading conditions.Subsequently,true triaxial compression tests incorporating multi-source disturbances were performed using a self-developed wide-low-frequency true triaxial system to simulate disturbance accumulation and damage evolution in granite.The results demonstrate that combined dynamic disturbances and unloading damage significantly accelerate strength degradation and trigger shear-slip failure along preferentially oriented blast-induced fractures,with strength reductions up to 16.7%.Layered failure was observed on the free surface of pre-damaged granite under biaxial loading,indicating a disturbance-induced fracture localization mechanism.Time-stress-fracture-energy coupling fields were constructed to reveal the spatiotemporal characteristics of fracture evolution.Critical precursor frequency bands(105-150,185-225,and 300-325 kHz)were identified,which serve as diagnostic signatures of impending failure.A dynamic instability mechanism driven by multi-source disturbance superposition and pre-damage evolution was established.Furthermore,a grouting-based wave-absorption control strategy was proposed to mitigate deep dynamic disasters by attenuating disturbance amplitude and reducing excitation frequency.
基金supported by the Science Fund for Creative Research Groups of National Natural Science Foundation of China(51221004)the National Natural Science Foundation of China(11172260,11372270,and 51375434)+2 种基金the Higher School Specialized Research Fund for the Doctoral Program(20110101110016)the Science and technology project of Zhejiang Province(2013C31086)the Fundamental Research Funds forthe Central Universities of China(2013XZZX005)
文摘During bipedal walking,it is critical to detect and adjust the robot postures by feedback control to maintain its normal state amidst multi-source random disturbances arising from some unavoidable uncertain factors.The radical basis function（RBF）neural network model of a five-link biped robot is established,and two certain disturbances and a randomly uncertain disturbance are then mixed with the optimal torques in the network model to study the performance of the biped robot by several evaluation indices and a specific Poincar′e map.In contrast with the simulations,the response varies as desired under optimal inputting while the output is fluctuating in the situation of disturbance driving.Simulation results from noise inputting also show that the dynamics of the robot is less sensitive to the disturbance of knee joint input of the swing leg than those of the other three joints,the response errors of the biped will be increasing with higher disturbance levels,and especially there are larger output fluctuations in the knee and hip joints of the swing leg.
文摘A new method of single sample polarization filtering is proposed. The algorithm is fast and suitable for the polarization processing of stationary or nonstationary polarized disturbed signals with one or more independent disturbances. A ground wave polarimetric radar with the ability of radio disturbance suppresion is then introduced. Some numerical results demonstrate the effectiveness of single sample polarization filtering method for ground wave polarimetric radar.
文摘The rolling mill vibration not only seriously causes the strip thickness heterogeneity, but also damages the rolling mill equipment and its electrical components. Existing vibration suppression methods are passive and mainly tune mechanical, hydraulic, electrical and rolling process parameters. A new active vibration suppression method was thus proposed using the disturbance estimation and compensation algorithm. Firstly, the hydraulic-mechanical coupling model of the rolling mill vibration was established, and an active vibration suppressor was designed based on the extended state observer. Then, through the numerical simulation, it is found that the vibration energy is reduced by 35.3% using the vibration suppressor, and the vibration suppressor is valid when the vibration frequency is lower than 60 Hz Finally, the vibration suppressor was applied to the in-site manufacturing, and the expected vibration suppression was obtained. The method makes the produced steel strip have more uniform thickness and further significantly increases the finished product ratio.
基金co-supported by the National Key R&D Program of China(No.2023YFB4704400)the Zhejiang Provincial Natural Science Foundation of China(No.LQ24F030012)the National Natural Science Foundation of China General Project(No.62373033)。
文摘A composite anti-disturbance predictive control strategy employing a Multi-dimensional Taylor Network(MTN)is presented for unmanned systems subject to time-delay and multi-source disturbances.First,the multi-source disturbances are addressed according to their specific characteristics as follows:(A)an MTN data-driven model,which is used for uncertainty description,is designed accompanied with the mechanism model to represent the unmanned systems;(B)an adaptive MTN filter is used to remove the influence of the internal disturbance;(C)an MTN disturbance observer is constructed to estimate and compensate for the influence of the external disturbance;(D)the Extended Kalman Filter(EKF)algorithm is utilized as the learning mechanism for MTNs.Second,to address the time-delay effect,a recursiveτstep-ahead MTN predictive model is designed utilizing recursive technology,aiming to mitigate the impact of time-delay,and the EKF algorithm is employed as its learning mechanism.Then,the MTN predictive control law is designed based on the quadratic performance index.By implementing the proposed composite controller to unmanned systems,simultaneous feedforward compensation and feedback suppression to the multi-source disturbances are conducted.Finally,the convergence of the MTN and the stability of the closed-loop system are established utilizing the Lyapunov theorem.Two exemplary applications of unmanned systems involving unmanned vehicle and rigid spacecraft are presented to validate the effectiveness of the proposed approach.
基金This work was supported by National Natural Science Foundation of China(Grant No.51709161)the Key Research and Development Program of Shandong Province(Grant Nos.2019GHY112061 and 2018GHY115045)+2 种基金Research and Innovation Team of Ocean Oil and Gas Development Engineering Structure,College of Civil Engineering and Architecture,Shandong University of Science and Technology(Grant No.2019TJKYTD01)Shandong Provincial Natural Science Foundation,China(Grant No.ZR2017BEE041)Science and technology innovation project for postgraduates of Shandong University of Science and Technology(Grant No.SDKDYC180327).
文摘An experimental investigation on the disturbance effect of jet-type active vibration suppression device on vortexinduced vibration of deep-sea riser was carried out in the wave-flow combined flume.The vibration suppression device was designed in which the jet pipe was horizontally fixed to the front end of the riser.By varying three different excitation spacings and multi-stage outflow velocities,the influence law of the dominant frequency,dimensionless displacement and other dynamic response parameters was studied under different excitation spacings,and the mechanism and sensitive characteristics of the disturbance suppression were explored.The results indicate that the variation of excitation spacing makes gas curtain enter the strong disturbed flow region at different velocities and angles,and the coupling relationship between excitation spacing and reduced velocity is the key factor to enter the strong disturbed flow region to achieve the optimal disturbance suppression.In the strong disturbed flow region,the influence of gas curtain on the dominant frequency is obviously affected by the flow velocity,while the vibration displacement is stable at the same amplitude and is weakly affected by the flow velocity.Gas curtain can effectively disturb the formation of vortex shedding,destroy the strong nonlinear coupled vibration of the riser,and achieve better vibration suppression effect.In the weak disturbed flow region,the vortex length of the riser tail is prolonged,the strong nonlinear coupled vibration of the riser is gradually restored,and the vibration suppression effect of the device gradually decreases.
基金supported by the National Natural Science Foundation of China(62203222)the Science and Technology Major Project of Jiangsu Province(BG2024041)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX24_0676).
文摘This paper investigates the high-performance control issues of systems affected by time-varying disturbances and measurement noise.Conventionally,active disturbance rejection control(ADRC)is a favorable control strategy to reject unknown disturbances and uncertainties.However,its control performance is limited because standard extended state observer(ESO)struggles to effectively estimate time-varying disturbances.The emergence of high-order ESO(HESO)alleviates the limitation.Unfortunately,it deteriorates the noise suppression capability when the disturbance rejection is enhanced.To tackle this challenge,an improved ADRC with cascade HESO(CHESO)is proposed.A comprehensive theoretical analysis associated with the performance of HESO is given for the first time.The presented analyses provide an intuitive understanding of the performance of HESO.Then,a novel CHESO is developed.The convergence of CHESO is proved via input-to-state stable theory.Extensive frequency domain analyses indicate that CHESO has stronger disturbance rejection and high-frequency noise attenuation performance than ESO and HESO without increasing the observer bandwidth.Comparative simulations conducted on a servo control system validate the effectiveness and preponderance of the proposed method.
基金supported by the National Natural Science Foundation of China(61803015).
文摘In order to enhance the dynamic control precision of inertial stabilization platform(ISP),a disturbance sliding mode observer(DSMO)is proposed in this paper suppressing disturbance torques inherent within the system.The control accuracy of ISP is fundamentally circumscribed by various disturbance torques in rotating shaft.Therefore,a dynamic model of ISP incorporating composite perturbations is established with regard to the stabilization of axis in the inertial reference frame.Subsequently,an online estimator for control loop uncertainties based on the sliding mode control algorithm is designed to estimate the aggregate disturbances of various parameters uncertainties and other unmodeled disturbances that cannot be accurately calibrated.Finally,the proposed DSMO is integrated into a classical proportional-integral-derivative(PID)control scheme,utilizing feedforward approach to compensate the composite disturbance in the control loop online.The effectiveness of the proposed disturbance observer is validated through simulation and hardware experimentation,demonstrating a significant improvement in the dynamic control performance and robustness of the classical PID controller extensively utilized in the field of engineering.
基金supported by the National Natural Science Foundation under Grant 62273189the Shandong Province Natural Science Foundation under Grant ZR2021MF005Systems Science Plus Joint Research Program of Qingdao University under Grant XT2024201 of China supporting this research work.
文摘This article investigates the anti-disturbance and stabilization problems for the nonlinear uncertain permanent magnet synchronous motor(PMSM)with stator voltage saturation and unknown load.A smooth switching mechanism is presented to structure the adaptive integral terminal sliding mode control(SMC)strategy.The control design consists of compensation control and nominal control,which improves the rapidity and accuracy of trajectory tracking.The smooth saturation model based on the error function is applied to approximate the voltage saturation phenomenon.Additionally,to deal with the adverse effects of various unknown disturbances,including model parameter uncertainties and unknown external load disturbances,an improved disturbance observer(DO)is proposed.This observer effectively suppresses the fluctuations caused by fixed gain during the starting period of the system.Finally,the experimental results under different conditions show that the proposed strategy has good tracking and disturbance suppression performances.
基金supported by the National Natural Science Foundation of China under Grant 52302458the CAS Project for Young Scientists in Basic Research,Grant No.YSBR-045.
文摘During the startup of the hydraulic turbine generators,the hybrid magnetic bearing support system exhibits displacement fluctuations,and the nonlinearity and strong coupling characteristics of the magnetic bearings limit the accuracy of rotor modeling,making traditional control methods difficult to adapt to parameter variations.To suppress startup disturbances and achieve a control strategy with low computational complexity and high precision,this paper proposes a five-degree-of-freedom hybrid magnetic bearing control strategy based on an improved cascaded reduced-order linear active disturbance rejection controller(CRLADRC).The front-stage reduced-order linear extended state observer(FRLESO)reduces the system’s computational complexity,enabling the system to maintain stability during motor startup disturbances.The second-stage reduced-order linear extended state observer(SRLESO)further enhances the system’s disturbance estimation accuracy while maintaining low computational complexity.Furthermore,the disturbance rejection and noise suppression capabilities are analyzed in the frequency domain and the stability of the proposed control method is proven using Lyapunov theory.Experimental results indicate that the proposed strategy effectively reduces displacement fluctuations in the hybrid magnetic bearing support system during motor startup,significantly enhancing the system’s robustness.
基金supported by National Natural Science Foundation of China(61125306,61273092,61301035,61304018,and 61411130160)National HighTechnology Research and Development Program of China(2014AA051901)+4 种基金Tianjin Science and Technology Supporting Program(14JCQNJC05400)Research Innovation Program of Tianjin University(2013XQ0101)Hubei Science and Technology Supporting Program(XYJ2014000314)Science Foundation of China Supported by Science and Technology on Aircraft Control Laboratory(20125848004)China Post-doctoral Science Foundation(2014M561559)
基金National Natural Science Foundation of China(No.61963029)Jiangxi Provincial Natural Science Foundation(Nos.20224BAB202027 and 20232ACB202007)。
文摘To solve the synchronization and tracking problems,a cooperative control scheme is proposed for a class of higher-order multi-input and multi-output(MIMO)nonlinear multi-agent systems(MASs)subjected to uncertainties and external disturbances.First,coupled relationships among Laplace matrix,leader-following adjacency matrix and consensus error are analyzed based on undirected graph.Furthermore,nonlinear disturbance observers(NDOs)are designed to estimate compounded disturbances in MASs,and a distributed cooperative anti-disturbance control protocol is proposed for high-order MIMO nonlinear MASs based on the outputs of NDOs and dynamic surface control approach.Finally,the feasibility and effectiveness of the proposed scheme are proven based on Lyapunov stability theory and simulation experiments.
基金Supported by the Smart Grid-National Science and Technology Major Project(2024ZD0801500)by the National Natural Science Foundation of China(52207211,U24B2085,U23A20655)by the Fundamental Research Funds for the Central Universities(JZ2024HGTB0259).
文摘The high penetration of renewable energy has led to the widespread emergence of weak grids,under which grid-following(GFL)inverters suffer from dynamic instability induced by phase-locked loops(PLL).Although reducing the bandwidth of the PLL can enhance system stability,it significantly degrades the ability of the inverter to reject power interaction disturbances.The inherent trade-off between the bandwidth of the PLL and its disturbance suppression capability are investigated.A cooperative strategy through a grid-forming(GFM)inverter to improve the robustness of GFL inverters without requiring hardware modifications is introduced.The simulation results validate that the proposed strategy effectively suppresses power interaction disturbances and enhances system stability under weak-grid scenarios.
基金supported by the National Natural Science Foundation of China(12302027,11702255)the Natural Science Foundation of Henan(232300421357)+1 种基金the Scientific Research Team Plan of Zhengzhou University of Aeronautics(23ZHTD01006)the Open Funding of Henan Key Laboratory of General Aviation Technology(ZHKF-240211)。
文摘Current research on active flutter suppression considering time delays tends to focus on fixed time delays.To address situations where the control loop may experience time-varying delays with uncertainty,a time-varying-delay Active Disturbance Rejection Control(TVD-ADRC)is proposed.First,a parameterized unsteady aerodynamic reduced-order model(ROM)based on a long short-term memory network is introduced into the aeroservoelastic modeling.This model is applied to predict unsteady aerodynamic forces and aeroservoelastic(ASE)behaviors across a wide range of Mach numbers.Its effectiveness in capturing the characteristics of unsteady aerodynamics is validated through comparisons with the high-fid elity computational fluid dynamics(CFD)simulations.Second,the proposed method integrates ADRC with a delayed input and a time-d elay identification module in the controller design.Specifically,the timevarying delay is identified using the cross-correlation function method with a moving window,and this method dynamically updates the time-delay compensation module.Additionally,a genetic algorithm is employed to optimize controller parameters,and the integral of the time-weighted absolute error is selected as the performance evaluation index for the control system.Finally,a three-degree-of-freedom aeroservoelastic system of an airfoil with a trailing-edge control surface is studied for flutter suppression.Flutter control under uncertain time-varying delays during flutter occurrence is investigated,and the impact of the magnitude of the time delay on the effectiveness of the flutter control is analyzed.Simulation results indicate that the proposed TVDADRC controller could effectively suppress the aeroelastic instabilities across a wide range of Mach numbers and effectively counteract the negative effects of time-varying delays.
基金Supported by the National Science Fund for Distinguished Young Scholars under Grant 52025073 and the Zhenjiang Key Research Program under Grant GY2020011.
文摘A modified four-dimensional linear active disturbance rejection control(LADRC)strategy is proposed for a dual three-phase permanent magnet synchronous generator(DTP-PMSG)system to reduce cross-coupling between the d and q axis currents in the d-q subspace and harmonic currents in the x-y subspace.In the d-q subspace,the proposed strategy uses a model-based LADRC to enhance the decoupling effect between the d and q axes and the disturbance rejection ability against parameter variation.In the x-y subspace,the 5th and 7th harmonic current suppression abilities are improved by using quasi-resonant units parallel to the extended state observer of the traditional LADRC.The proposed modified LADRC strategy improved both the steady-state performance and dynamic response of the DTP-PMSG system.The experimental results demonstrate that the proposed strategy is both feasible and effective.
文摘针对四旋翼无人机吊挂系统的负载摆动抑制和轨迹跟踪问题,提出一种线性自抗扰控制器(Liner Active Disturbance Rejection Controller,LADRC)的轨迹跟踪控制方法。首先,考虑到四旋翼吊挂负载耦合飞行的未知外界扰动与模型的动态不确定性,为飞行器的姿态、位置设计线性自抗扰控制器,通过扩张状态观测器(Extended State Observer,ESO)观测负载摆动和环境干扰对机体的扰动,并对控制量进行相应补偿,来抑制外界和负载摆动给机体带来的干扰,保证无人机飞行过程中的稳定性。其次,针对四旋翼无人机吊挂系统在飞行过程中负载摆角过大的问题,设计加速度规划摆角抑制算法,通过摆角的实时反馈对四旋翼无人机的位置轨迹输入进行路径规划,实现飞行过程中负载摆动的抑制。最后,通过仿真结果证明该控制方法对飞行器的位置及姿态控制效果较好,同时验证了所提的轨迹规划方法能够有效抑制吊挂物的摆动,且对干扰的鲁棒性较强。
