Instability of a wake controlled by a streamwise Lorentz force is investigated through a Floquet stability analysis. The streamwise Lorentz force, which is a two-dimensional control input created by an electromagnetic...Instability of a wake controlled by a streamwise Lorentz force is investigated through a Floquet stability analysis. The streamwise Lorentz force, which is a two-dimensional control input created by an electromagnetic actuator located on the cylinder surface,adjusts the base flow to affect the three-dimensional wake instability and achieve wake stabilization and transition delay. The instability mode at a Reynolds number Re = 300 can be transformed from B to A with N = 1.0, where N is an interaction number representing the strength of the Lorentz force relative to the inertial force in the fluid. The wake flow is Floquet stable when N increases to 1.3. The spanwise perturbation wavelengths are 3.926 D and 0.822 D in the modes A and B, respectively, where D is the cylinder diameter. In addition, the oscillating amplitudes of drag and lift are reduced with the increase in the interaction number. Particle tracing is used to explore the essential physical mechanism for mode transformation. The path lines show that suppression of flow separation hinders the fluid deformation and rotation, leading to the decrease in elliptic and hyperbolic instability regions, which is the material cause of mode transformation.All of the results indicate that wake stabilization and transition delay can be achieved under open-loop active control via the streamwise Lorentz force.展开更多
Permanent magnet synchronous motor based electro-mechanical actuation servo drives have widespread applications in the aviation field,such as unmanned aerial vehicle electric servos,electric cabin doors,and mechanical...Permanent magnet synchronous motor based electro-mechanical actuation servo drives have widespread applications in the aviation field,such as unmanned aerial vehicle electric servos,electric cabin doors,and mechanical arms.The performance of the servo drive,which encompasses the response to the torque,efficiency,control bandwidth and the steady-state positioning accuracy,significantly influences the performance of the aviation actuation.Consequently,enhancing the control bandwidth and refining the positioning accuracy of aviation electro-mechanical actuation servo drives have emerged as a focal point of research.This paper investigates the multi-source disturbances present in aviation electro-mechanical actuation servo systems and summarizes recent research on high-performance servo control methods based on active disturbance rejection control(ADRC).We present a comprehensive overview of the research status pertaining to servo control architecture,strategies for suppressing disturbances in the current loop,and ADRC-based strategies for the position loop.We delineate the research challenges and difficulties encountered by aviation electro-mechanical actuation servo drive control technology.展开更多
The objective of this paper is to present a robust safety-critical control system based on the active disturbance rejection control approach, designed to guarantee safety even in the presence of model inaccuracies, un...The objective of this paper is to present a robust safety-critical control system based on the active disturbance rejection control approach, designed to guarantee safety even in the presence of model inaccuracies, unknown dynamics, and external disturbances. The proposed method combines control barrier functions and control Lyapunov functions with a nonlinear extended state observer to produce a robust and safe control strategy for dynamic systems subject to uncertainties and disturbances. This control strategy employs an optimization-based control, supported by the disturbance estimation from a nonlinear extended state observer. Using a quadratic programming algorithm, the controller computes an optimal, stable, and safe control action at each sampling instant. The effectiveness of the proposed approach is demonstrated through numerical simulations of a safety-critical interconnected adaptive cruise control system.展开更多
Spider mites are significant pests in agricultural production.The increasing resistance of spider mites,along with environmental pollution and ecological imbalance caused by their control,is primarily attributed to th...Spider mites are significant pests in agricultural production.The increasing resistance of spider mites,along with environmental pollution and ecological imbalance caused by their control,is primarily attributed to the long-term use of chemical acaricides in agriculture.In contrast,bioactive substances of biological origin offer advantages such as wide availability,environmental friendliness,and low tendency to induce resistance,making them a research hotspot for spider mite control.This review summarizes recent advances in the use of plant-derived active compounds(exemplified by extracts from Veratrum rhizomes),RNA interference(RNAi)technology,and microorganism-derived active substances for controlling spider mites.These bioactive agents exert acaricidal effects by disrupting the nervous system,interfering with metabolic processes,or silencing key genes in mites,demonstrating favorable efficacy and considerable potential for development.However,challenges remain,including poor environmental stability,slow action,high production costs,and insufficient understanding of their effects on non-target organisms.Therefore,future research should focus on the screening and development of novel bioactive substances of biological origin,elucidation of their mechanisms of action,optimization of formulation technologies,and assessment of their ecological safety.These efforts will provide valuable insights for promoting the advancement of bioactive substances and supporting sustainable agricultural development.展开更多
Pump valve pipeline vibration brings serious safety hazards to the operation of the equipment,for the pump valve system in the process of variable flow,variable speed,variable openings lead to excessive pipeline vibra...Pump valve pipeline vibration brings serious safety hazards to the operation of the equipment,for the pump valve system in the process of variable flow,variable speed,variable openings lead to excessive pipeline vibration.An active damping device(ADD)is used to the vibration of the pump valve pipeline system to apply the control force,to achieve the active control of the pipeline vibration.A pump-valve pipeline vibration test bench was built to compare the control effect of active damping device on pipeline vibration under different pump valve working conditions,and the results show that applying ADD control could effectively suppress the vibration of the pump valve pipeline and enhance the stability of the equipment during operation.At different pump operating rotation frequencies,the vibration amplitude of the pump valve pipeline in working frequency and its multiple frequencies are also effectively suppressed,with the maximum amplitude reduction of more than 60%.For the valve vibration caused by different operating openings,the vibration of the highest reduction of 68%,and the centrifugal pump drive shaft vi-bration reduced by up to 73%,which provides a new idea for vibration control of pump valve pipeline system.展开更多
The study of Mecanum mobile robots typically assumes motion on planar surfaces,while the challenges posed by inclined terrains remain largely unexplored,leaving a significant gap in control applications for such scena...The study of Mecanum mobile robots typically assumes motion on planar surfaces,while the challenges posed by inclined terrains remain largely unexplored,leaving a significant gap in control applications for such scenarios.In this context,two critical issues emerge:the gravitational pull caused by adding a potential energy term in the robot dynamics,which drives the vehicle downhill,and several positioning errors due to vibrations and slippage of the Mecanum wheel.To address these challenges,this work presents an Active Disturbance Rejection Control(ADRC)-based framework designed to enable accurate tracking on inclined surfaces,despite the compounded effects of gravitational forces and slippage.Unlike conventional controllers,the proposed method requires minimal model knowledge while actively compensates for unknown dynamics and external disturbances in real time.A complete theoretical formulation is provided,supported by numerical simulations and comprehensive experimental validation.Results demonstrate that the ADRC structure significantly outperforms not only the traditional proportional-integral-derivative(PID)control but also a robust variant of PID combined with a Quasi-Sliding Mode control(PID-QSMC)strategy,achieving superior tracking.Notably,this study offers an important experimental validation of ADRC for Mecanum-wheeled robots operating on inclined surfaces.It contributes a practical and scalable solution to extend their operational capabilities beyond flat environments.展开更多
A theoretical analysis regarding active vibration control of rotating machines with current-controlled electrodynamic actuators between machine feet and steel frame foundation and with velocity feedback of the machine...A theoretical analysis regarding active vibration control of rotating machines with current-controlled electrodynamic actuators between machine feet and steel frame foundation and with velocity feedback of the machine feet vibrations is presented.First,a generalized mathematical formulation is derived based on a state-space description which can be used for different kinds of models(1D,2D,and 3D models).It is shown that under special boundary conditions,the control parameters can be directly implemented into the stiffness and damping matrices of the system.Based on the generalized mathematical formulation,an example of a rotating machine—described by a 2D model—with journal bearings,flexible rotor,current-controlled electrodynamic actuators,steel frame foundation,and velocity feedback of the machine feet vibrations is presented where the effectiveness of the described active vibration control system is demonstrated.展开更多
With the growing adoption of artificial intelligence algorithms and neural networks,online learning and adaptive methods for updating the bandwidth have become increasingly prevalent.However,the conditions required to...With the growing adoption of artificial intelligence algorithms and neural networks,online learning and adaptive methods for updating the bandwidth have become increasingly prevalent.However,the conditions required to ensure closed-loop stability when employing a time-varying bandwidth,as well as the supporting mathematical foundations,remain insufficiently studied.This paper investigates the stability condition for active disturbance rejection control(ADRC)with a time-varying bandwidth extended state observer(ESO).A new stability condition is derived,which means that the upper bound of rate of change for ESO bandwidth should be restricted.Moreover,under the proposed condition,the closed-loop stability of ADRC with a time-varying bandwidth observer is rigorously proved for nonlinear uncertainties.In simulations,the necessity of the proposed condition is illustrated,demonstrating that the rate of change of ESO bandwidth is crucial for closed-loop stability.展开更多
This paper aims to fuse two well-established and,at the same time,opposed control techniques,namely,model predictive control(MPC)and active disturbance rejection control(ADRC),to develop a dynamic motion controller fo...This paper aims to fuse two well-established and,at the same time,opposed control techniques,namely,model predictive control(MPC)and active disturbance rejection control(ADRC),to develop a dynamic motion controller for a laser beam steering system.The proposed technique uses the ADRC philosophy to lump disturbances and model uncertainties into a total disturbance.Then,the total disturbance is estimated via a discrete extended state disturbance observer(ESO),and it is used to(1)handle the system constraints in a quadratic optimization problem and(2)injected as a feedforward term to the plant to reject the total disturbance,together with the feedback term obtained by the MPC.The main advantage of the proposed approach is that the MPC is designed based on a straightforward integrator-chain model such that a simple convex optimization problem is performed.Several experiments show the real-time closed-loop performance regarding trajectory tracking and disturbance rejection.Owing to simplicity,the self-contained approach MPC+ESO becomes a Frugal MPC,which is computationally economical,adaptable,efficient,resilient,and suitable for applications where on-board computational resources are limited.展开更多
This paper investigates the active traveling wave vibration control of an elastic supported rotating porous aluminium conical shell(CS)under impact loading.Piezoelectric smart materials in the form of micro fiber comp...This paper investigates the active traveling wave vibration control of an elastic supported rotating porous aluminium conical shell(CS)under impact loading.Piezoelectric smart materials in the form of micro fiber composites(MFCs)are used as actuators and sensors.To this end,a metal pore truncated CS with MFCs attached to its surface is considered.Adding artificial virtual springs at two edges of the truncated CS achieves various elastic supported boundaries by changing the spring stiffness.Based on the first-order shear deformation theory(FSDT),minimum energy principle,and artificial virtual spring technology,the theoretical formulations considering the electromechanical coupling are derived.The comparison of the natural frequency of the present results with the natural frequencies reported in previous literature evaluates the accuracy of the present approach.To study the vibration control,the integral quadrature method in conjunction with the differential quadrature approximation in the length direction is used to discretize the partial differential dynamical system to form a set of ordinary differential equations.With the aid of the velocity negative feedback method,both the time history and the input control voltage on the actuator are demonstrated to present the effects of velocity feedback gain,pore distribution type,semi-vertex angle,impact loading,and rotational angular velocity on the traveling wave vibration control.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
This paper presents a novel active disturbance rejection control(ADRC)scheme based on a cascade connection of generalized proportional integral observers(GPIOs)with internal models designed to estimate both polynomial...This paper presents a novel active disturbance rejection control(ADRC)scheme based on a cascade connection of generalized proportional integral observers(GPIOs)with internal models designed to estimate both polynomial and resonant disturbances.In this estimator structure,referred to as Cascade GPIO(CGPIO),the total disturbance sensitivity is the product of the sensitivities at each cascade level.This approach improves system performance against both periodic and non-periodic disturbances and enhances robustness under frequency variations in harmonic components.Additionally,the decoupled nature of the estimator reduces the order of the GPIOs,thereby simplifying tuning and limiting observer gains.The proposed control scheme is supported by a frequency-domain analysis and is experimentally validated in the current control of a grid-connected converter subject to control gain uncertainties,harmonic distortion,frequency deviations,and measurement noise.Experimental results demonstrate that the CGPIO-based ADRC outperforms benchmark solutions,including proportional-integral(PI)and proportional-resonant(PR)controllers.展开更多
Patients with complete spinal cord injury retain the potential for volitional muscle activity in muscles located below the spinal injury level.However,because of prolonged inactivity,initial attempts to activate these...Patients with complete spinal cord injury retain the potential for volitional muscle activity in muscles located below the spinal injury level.However,because of prolonged inactivity,initial attempts to activate these muscles may not effectively engage any of the remaining neurons in the descending pathway.A previous study unexpectedly found that a brief clinical round of passive activity significantly increased volitional muscle activation,as measured by surface electromyography.In this study,we further explored the effect of passive activity on surface electromyographic signals during volitional control tasks among individuals with complete spinal cord injury.Eleven patients with chronic complete thoracic spinal cord injury were recruited.Surface electromyography data from eight major leg muscles were acquired and compared before and after the passive activity protocol.The results indicated that the passive activity led to an increased number of activated volitional muscles and an increased frequency of activation.Although the cumulative root mean square of surface electromyography amplitude for volitional control of movement showed a slight increase after passive activity,the difference was not statistically significant.These findings suggest that brief passive activity may enhance the ability to initiate volitional muscle activity during surface electromyography tasks and underscore the potential of passive activity for improving residual motor control among patients with motor complete spinal cord injury.展开更多
The active vibration control technology has been successfully applied to several helicopter types.However,with the increasing of control scale,traditional centralized control algorithms are experiencing significant in...The active vibration control technology has been successfully applied to several helicopter types.However,with the increasing of control scale,traditional centralized control algorithms are experiencing significant increase of computational complexity and physical implementation challenging.To address this issue,a diffusion collaboration-based distributed Filtered-x Least Mean Square algorithm applied to active vibration control is proposed,drawing inspiration from the concept of data fusion in wireless sensor network.This algorithm distributes the computation load to each node,and constructs the active vibration control network topology of large-scale system by discarding the weak coupling secondary paths between nodes,achieving distributed active vibration control.In order to thoroughly validate the effectiveness and superiority of this algorithm,a helicopter fuselage model is designed as the research object.Firstly,the excellent vibration reduction performance of the proposed algorithm is confirmed through simulations.Subsequently,specialized node control units are developed,which utilize STM32 microcontroller as the processing unit.Further,a distributed control system is constructed based on multi-processor collaboration.Building on this foundation,a large-scale active vibration control experimental platform is established.Based on the platform,experiments are carried out,involving the 4-input 4-output system and the 8-input 8-output system.The experimental results demonstrate that under steady-state harmonic excitation,the proposed algorithm not only ensures control effectiveness but also reduces computational complexity by 50%,exhibiting faster convergence speed compared with traditional centralized algorithms.Under time-varying external excitation,the proposed algorithm demonstrates rapid tracking of vibration changes,with vibration amplitudes at all controlled points declining by over 94%,proving the strong robustness and adaptive capability of the algorithm.展开更多
In this paper, the attitude tracking and load relief control problems against wind disturbances and uncertain aerodynamics as well as the engine thrust of launch vehicles are studied.Firstly, a framework of Compensate...In this paper, the attitude tracking and load relief control problems against wind disturbances and uncertain aerodynamics as well as the engine thrust of launch vehicles are studied.Firstly, a framework of Compensated Acceleration Feedback based Active Disturbance Rejection Control(CAF-ADRC) is established to achieve both desired attitude tracking and load relief performances. In particular, the total disturbance that includes the effects caused by both aerocoefficient perturbations and disturbances is estimated by constructing an Extended State Observer(ESO) to achieve attitude tracking. Furthermore, combined with the normal acceleration due to the engine thrust, the accelerometer measurement is also compensated to enhance the load relief effect.Secondly, the quantitative analysis of ESO and the entire closed-loop system are studied. It can be concluded that the desired attitude tracking and load relief performances can be achieved simultaneously under the proposed approach. Besides, tuning laws of the proposed approach are systematically given, which are divided into ESO, Proportional Derivative(PD) and Compensated Acceleration Feedback(CAF) modules. Moreover, the performances under CAF-ADRC approach can be better than those under CAF based PD(CAF-PD) approach by tuning load relief gain.Finally, the approach presented is applied to a typical control problem of launch vehicles with wind disturbances and parameter uncertainties.展开更多
This paper proposes a modified iterative learning control(MILC)periodical feedback-feedforward algorithm to reduce the vibration of a rotor caused by coupled unbalance and parallel misalignment.The control of the vibr...This paper proposes a modified iterative learning control(MILC)periodical feedback-feedforward algorithm to reduce the vibration of a rotor caused by coupled unbalance and parallel misalignment.The control of the vibration of the rotor is provided by an active magnetic actuator(AMA).The iterative gain of the MILC algorithm here presented has a self-adjustment based on the magnitude of the vibration.Notch filters are adopted to extract the synchronous(1×Ω)and twice rotational frequency(2×Ω)components of the rotor vibration.Both the notch frequency of the filter and the size of feedforward storage used during the experiment have a real-time adaptation to the rotational speed.The method proposed in this work can provide effective suppression of the vibration of the rotor in case of sudden changes or fluctuations of the rotor speed.Simulations and experiments using the MILC algorithm proposed here are carried out and give evidence to the feasibility and robustness of the technique proposed.展开更多
This paper addresses the sampled-data multi-objective active suspension control problem for an in-wheel motor driven electric vehicle subject to stochastic sampling periods and asynchronous premise variables.The focus...This paper addresses the sampled-data multi-objective active suspension control problem for an in-wheel motor driven electric vehicle subject to stochastic sampling periods and asynchronous premise variables.The focus is placed on the scenario that the dynamical state of the half-vehicle active suspension system is transmitted over an in-vehicle controller area network that only permits the transmission of sampled data packets.For this purpose,a stochastic sampling mechanism is developed such that the sampling periods can randomly switch among different values with certain mathematical probabilities.Then,an asynchronous fuzzy sampled-data controller,featuring distinct premise variables from the active suspension system,is constructed to eliminate the stringent requirement that the sampled-data controller has to share the same grades of membership.Furthermore,novel criteria for both stability analysis and controller design are derived in order to guarantee that the resultant closed-loop active suspension system is stochastically stable with simultaneous𝐻2 and𝐻∞performance requirements.Finally,the effectiveness of the proposed stochastic sampled-data multi-objective control method is verified via several numerical cases studies in both time domain and frequency domain under various road disturbance profiles.展开更多
Addressing issues such as the disconnect between theory and practice and low student engagement in control system education,this paper uses the course“The Working Process of Open-Loop Control Systems”as a case study...Addressing issues such as the disconnect between theory and practice and low student engagement in control system education,this paper uses the course“The Working Process of Open-Loop Control Systems”as a case study to explore the integration of AI technology with the“project-guided and task-driven”teaching model.By constructing a four-dimensional teaching framework of“situation-task-activity-evaluation,”AI tools are embedded in project practices such as the construction of a mechanical timed flower watering device and the optimization of a digital timed flower watering device,achieving precision,interactivity,and personalization in the teaching process.Teaching practice demonstrates that this model significantly enhances students’technical awareness,materialization capabilities,and engineering thinking,providing a reference for the teaching reform of technical courses in high school education.展开更多
The virtual synchronous generator(VSG)technology has been proposed to address the problem of system frequency and active power oscillation caused by grid-connected new energy power sources.However,the traditional volt...The virtual synchronous generator(VSG)technology has been proposed to address the problem of system frequency and active power oscillation caused by grid-connected new energy power sources.However,the traditional voltage-current double-closed-loop control used in VSG has the disadvantages of poor disturbance immunity and insufficient dynamic response.In light of the issues above,a virtual synchronous generator voltage outer-loop control strategy based on improved linear autonomous disturbance rejection control(ILADRC)is put forth for consideration.Firstly,an improved first-order linear self-immunity control structure is established for the characteristics of the voltage outer loop;then,the effects of two key control parameters-observer bandwidthω_(0)and controller bandwidthω_(c)on the control system are analyzed,and the key parameters of ILADRC are optimally tuned online using improved gray wolf optimizer-radial basis function(IGWO-RBF)neural network.A simulationmodel is developed using MATLAB to simulate,analyze,and compare the method introduced in this paper.Simulations are performed with the traditional control strategy for comparison,and the results demonstrate that the proposed control method offers superior anti-interference performance.It effectively addresses power and frequency oscillation issues and enhances the stability of the VSG during grid-connected operation.展开更多
Deep neural network(DNN)models have achieved remarkable performance across diverse tasks,leading to widespread commercial adoption.However,training high-accuracy models demands extensive data,substantial computational...Deep neural network(DNN)models have achieved remarkable performance across diverse tasks,leading to widespread commercial adoption.However,training high-accuracy models demands extensive data,substantial computational resources,and significant time investment,making them valuable assets vulnerable to unauthorized exploitation.To address this issue,this paper proposes an intellectual property(IP)protection framework for DNN models based on feature layer selection and hyper-chaotic mapping.Firstly,a sensitivity-based importance evaluation algorithm is used to identify the key feature layers for encryption,effectively protecting the core components of the model.Next,the L1 regularization criterion is applied to further select high-weight features that significantly impact the model’s performance,ensuring that the encryption process minimizes performance loss.Finally,a dual-layer encryption mechanism is designed,introducing perturbations into the weight values and utilizing hyperchaotic mapping to disrupt channel information,further enhancing the model’s security.Experimental results demonstrate that encrypting only a small subset of parameters effectively reduces model accuracy to random-guessing levels while ensuring full recoverability.The scheme exhibits strong robustness against model pruning and fine-tuning attacks and maintains consistent performance across multiple datasets,providing an efficient and practical solution for authorization-based DNN IP protection.展开更多
基金Project supported by the Specialized Research Fund for the Doctoral Program of Higher Education(No.20133219110039)
文摘Instability of a wake controlled by a streamwise Lorentz force is investigated through a Floquet stability analysis. The streamwise Lorentz force, which is a two-dimensional control input created by an electromagnetic actuator located on the cylinder surface,adjusts the base flow to affect the three-dimensional wake instability and achieve wake stabilization and transition delay. The instability mode at a Reynolds number Re = 300 can be transformed from B to A with N = 1.0, where N is an interaction number representing the strength of the Lorentz force relative to the inertial force in the fluid. The wake flow is Floquet stable when N increases to 1.3. The spanwise perturbation wavelengths are 3.926 D and 0.822 D in the modes A and B, respectively, where D is the cylinder diameter. In addition, the oscillating amplitudes of drag and lift are reduced with the increase in the interaction number. Particle tracing is used to explore the essential physical mechanism for mode transformation. The path lines show that suppression of flow separation hinders the fluid deformation and rotation, leading to the decrease in elliptic and hyperbolic instability regions, which is the material cause of mode transformation.All of the results indicate that wake stabilization and transition delay can be achieved under open-loop active control via the streamwise Lorentz force.
基金supported by the National Natural Science Foundation of China(Nos.52177059 and 52407064).
文摘Permanent magnet synchronous motor based electro-mechanical actuation servo drives have widespread applications in the aviation field,such as unmanned aerial vehicle electric servos,electric cabin doors,and mechanical arms.The performance of the servo drive,which encompasses the response to the torque,efficiency,control bandwidth and the steady-state positioning accuracy,significantly influences the performance of the aviation actuation.Consequently,enhancing the control bandwidth and refining the positioning accuracy of aviation electro-mechanical actuation servo drives have emerged as a focal point of research.This paper investigates the multi-source disturbances present in aviation electro-mechanical actuation servo systems and summarizes recent research on high-performance servo control methods based on active disturbance rejection control(ADRC).We present a comprehensive overview of the research status pertaining to servo control architecture,strategies for suppressing disturbances in the current loop,and ADRC-based strategies for the position loop.We delineate the research challenges and difficulties encountered by aviation electro-mechanical actuation servo drive control technology.
基金supported by the Fondo para el Primer Proyecto of the Comitépara el Desarrollo de la Investigación(CODI)at the Universidad de Antioquia(Grant Number PRV2024-78509)。
文摘The objective of this paper is to present a robust safety-critical control system based on the active disturbance rejection control approach, designed to guarantee safety even in the presence of model inaccuracies, unknown dynamics, and external disturbances. The proposed method combines control barrier functions and control Lyapunov functions with a nonlinear extended state observer to produce a robust and safe control strategy for dynamic systems subject to uncertainties and disturbances. This control strategy employs an optimization-based control, supported by the disturbance estimation from a nonlinear extended state observer. Using a quadratic programming algorithm, the controller computes an optimal, stable, and safe control action at each sampling instant. The effectiveness of the proposed approach is demonstrated through numerical simulations of a safety-critical interconnected adaptive cruise control system.
文摘Spider mites are significant pests in agricultural production.The increasing resistance of spider mites,along with environmental pollution and ecological imbalance caused by their control,is primarily attributed to the long-term use of chemical acaricides in agriculture.In contrast,bioactive substances of biological origin offer advantages such as wide availability,environmental friendliness,and low tendency to induce resistance,making them a research hotspot for spider mite control.This review summarizes recent advances in the use of plant-derived active compounds(exemplified by extracts from Veratrum rhizomes),RNA interference(RNAi)technology,and microorganism-derived active substances for controlling spider mites.These bioactive agents exert acaricidal effects by disrupting the nervous system,interfering with metabolic processes,or silencing key genes in mites,demonstrating favorable efficacy and considerable potential for development.However,challenges remain,including poor environmental stability,slow action,high production costs,and insufficient understanding of their effects on non-target organisms.Therefore,future research should focus on the screening and development of novel bioactive substances of biological origin,elucidation of their mechanisms of action,optimization of formulation technologies,and assessment of their ecological safety.These efforts will provide valuable insights for promoting the advancement of bioactive substances and supporting sustainable agricultural development.
基金The Fundamental Research Funds for the Central Universities(JD2423)。
文摘Pump valve pipeline vibration brings serious safety hazards to the operation of the equipment,for the pump valve system in the process of variable flow,variable speed,variable openings lead to excessive pipeline vibration.An active damping device(ADD)is used to the vibration of the pump valve pipeline system to apply the control force,to achieve the active control of the pipeline vibration.A pump-valve pipeline vibration test bench was built to compare the control effect of active damping device on pipeline vibration under different pump valve working conditions,and the results show that applying ADD control could effectively suppress the vibration of the pump valve pipeline and enhance the stability of the equipment during operation.At different pump operating rotation frequencies,the vibration amplitude of the pump valve pipeline in working frequency and its multiple frequencies are also effectively suppressed,with the maximum amplitude reduction of more than 60%.For the valve vibration caused by different operating openings,the vibration of the highest reduction of 68%,and the centrifugal pump drive shaft vi-bration reduced by up to 73%,which provides a new idea for vibration control of pump valve pipeline system.
文摘The study of Mecanum mobile robots typically assumes motion on planar surfaces,while the challenges posed by inclined terrains remain largely unexplored,leaving a significant gap in control applications for such scenarios.In this context,two critical issues emerge:the gravitational pull caused by adding a potential energy term in the robot dynamics,which drives the vehicle downhill,and several positioning errors due to vibrations and slippage of the Mecanum wheel.To address these challenges,this work presents an Active Disturbance Rejection Control(ADRC)-based framework designed to enable accurate tracking on inclined surfaces,despite the compounded effects of gravitational forces and slippage.Unlike conventional controllers,the proposed method requires minimal model knowledge while actively compensates for unknown dynamics and external disturbances in real time.A complete theoretical formulation is provided,supported by numerical simulations and comprehensive experimental validation.Results demonstrate that the ADRC structure significantly outperforms not only the traditional proportional-integral-derivative(PID)control but also a robust variant of PID combined with a Quasi-Sliding Mode control(PID-QSMC)strategy,achieving superior tracking.Notably,this study offers an important experimental validation of ADRC for Mecanum-wheeled robots operating on inclined surfaces.It contributes a practical and scalable solution to extend their operational capabilities beyond flat environments.
文摘A theoretical analysis regarding active vibration control of rotating machines with current-controlled electrodynamic actuators between machine feet and steel frame foundation and with velocity feedback of the machine feet vibrations is presented.First,a generalized mathematical formulation is derived based on a state-space description which can be used for different kinds of models(1D,2D,and 3D models).It is shown that under special boundary conditions,the control parameters can be directly implemented into the stiffness and damping matrices of the system.Based on the generalized mathematical formulation,an example of a rotating machine—described by a 2D model—with journal bearings,flexible rotor,current-controlled electrodynamic actuators,steel frame foundation,and velocity feedback of the machine feet vibrations is presented where the effectiveness of the described active vibration control system is demonstrated.
基金supported partially by the National Natural Science Foundation(No.62473344)the T-Flight Laboratory in ShanXi Provincial(No.GSFC2024NBKY05)+1 种基金the Natural Science Basic Research Program of Shaanxi(No.2025JC-YBQN-035)the National Natural Science Foundation of China(Grant No.92471204).
文摘With the growing adoption of artificial intelligence algorithms and neural networks,online learning and adaptive methods for updating the bandwidth have become increasingly prevalent.However,the conditions required to ensure closed-loop stability when employing a time-varying bandwidth,as well as the supporting mathematical foundations,remain insufficiently studied.This paper investigates the stability condition for active disturbance rejection control(ADRC)with a time-varying bandwidth extended state observer(ESO).A new stability condition is derived,which means that the upper bound of rate of change for ESO bandwidth should be restricted.Moreover,under the proposed condition,the closed-loop stability of ADRC with a time-varying bandwidth observer is rigorously proved for nonlinear uncertainties.In simulations,the necessity of the proposed condition is illustrated,demonstrating that the rate of change of ESO bandwidth is crucial for closed-loop stability.
基金support through his Master scholarshipThe Vicerrectoría de Investigación y Estudios de Posgrado(VIEP-BUAP)partially funded this work under grant number 00593-PV/2025.
文摘This paper aims to fuse two well-established and,at the same time,opposed control techniques,namely,model predictive control(MPC)and active disturbance rejection control(ADRC),to develop a dynamic motion controller for a laser beam steering system.The proposed technique uses the ADRC philosophy to lump disturbances and model uncertainties into a total disturbance.Then,the total disturbance is estimated via a discrete extended state disturbance observer(ESO),and it is used to(1)handle the system constraints in a quadratic optimization problem and(2)injected as a feedforward term to the plant to reject the total disturbance,together with the feedback term obtained by the MPC.The main advantage of the proposed approach is that the MPC is designed based on a straightforward integrator-chain model such that a simple convex optimization problem is performed.Several experiments show the real-time closed-loop performance regarding trajectory tracking and disturbance rejection.Owing to simplicity,the self-contained approach MPC+ESO becomes a Frugal MPC,which is computationally economical,adaptable,efficient,resilient,and suitable for applications where on-board computational resources are limited.
基金Supported by the National Natural Science Foundation of China(Nos.12272056 and 11832002)。
文摘This paper investigates the active traveling wave vibration control of an elastic supported rotating porous aluminium conical shell(CS)under impact loading.Piezoelectric smart materials in the form of micro fiber composites(MFCs)are used as actuators and sensors.To this end,a metal pore truncated CS with MFCs attached to its surface is considered.Adding artificial virtual springs at two edges of the truncated CS achieves various elastic supported boundaries by changing the spring stiffness.Based on the first-order shear deformation theory(FSDT),minimum energy principle,and artificial virtual spring technology,the theoretical formulations considering the electromechanical coupling are derived.The comparison of the natural frequency of the present results with the natural frequencies reported in previous literature evaluates the accuracy of the present approach.To study the vibration control,the integral quadrature method in conjunction with the differential quadrature approximation in the length direction is used to discretize the partial differential dynamical system to form a set of ordinary differential equations.With the aid of the velocity negative feedback method,both the time history and the input control voltage on the actuator are demonstrated to present the effects of velocity feedback gain,pore distribution type,semi-vertex angle,impact loading,and rotational angular velocity on the traveling wave vibration control.
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.
文摘This paper presents a novel active disturbance rejection control(ADRC)scheme based on a cascade connection of generalized proportional integral observers(GPIOs)with internal models designed to estimate both polynomial and resonant disturbances.In this estimator structure,referred to as Cascade GPIO(CGPIO),the total disturbance sensitivity is the product of the sensitivities at each cascade level.This approach improves system performance against both periodic and non-periodic disturbances and enhances robustness under frequency variations in harmonic components.Additionally,the decoupled nature of the estimator reduces the order of the GPIOs,thereby simplifying tuning and limiting observer gains.The proposed control scheme is supported by a frequency-domain analysis and is experimentally validated in the current control of a grid-connected converter subject to control gain uncertainties,harmonic distortion,frequency deviations,and measurement noise.Experimental results demonstrate that the CGPIO-based ADRC outperforms benchmark solutions,including proportional-integral(PI)and proportional-resonant(PR)controllers.
基金supported by the Fundamental Research Funds for Central Public Welfare Research Institute,No.2020CZ-5(to WS and GS)the National Natural Science Foundation of China,No.31970970(to JSR)Fundamental Research Funds for the Central Universities,No.YWF-23-YG-QB-010(to JSR)。
文摘Patients with complete spinal cord injury retain the potential for volitional muscle activity in muscles located below the spinal injury level.However,because of prolonged inactivity,initial attempts to activate these muscles may not effectively engage any of the remaining neurons in the descending pathway.A previous study unexpectedly found that a brief clinical round of passive activity significantly increased volitional muscle activation,as measured by surface electromyography.In this study,we further explored the effect of passive activity on surface electromyographic signals during volitional control tasks among individuals with complete spinal cord injury.Eleven patients with chronic complete thoracic spinal cord injury were recruited.Surface electromyography data from eight major leg muscles were acquired and compared before and after the passive activity protocol.The results indicated that the passive activity led to an increased number of activated volitional muscles and an increased frequency of activation.Although the cumulative root mean square of surface electromyography amplitude for volitional control of movement showed a slight increase after passive activity,the difference was not statistically significant.These findings suggest that brief passive activity may enhance the ability to initiate volitional muscle activity during surface electromyography tasks and underscore the potential of passive activity for improving residual motor control among patients with motor complete spinal cord injury.
文摘The active vibration control technology has been successfully applied to several helicopter types.However,with the increasing of control scale,traditional centralized control algorithms are experiencing significant increase of computational complexity and physical implementation challenging.To address this issue,a diffusion collaboration-based distributed Filtered-x Least Mean Square algorithm applied to active vibration control is proposed,drawing inspiration from the concept of data fusion in wireless sensor network.This algorithm distributes the computation load to each node,and constructs the active vibration control network topology of large-scale system by discarding the weak coupling secondary paths between nodes,achieving distributed active vibration control.In order to thoroughly validate the effectiveness and superiority of this algorithm,a helicopter fuselage model is designed as the research object.Firstly,the excellent vibration reduction performance of the proposed algorithm is confirmed through simulations.Subsequently,specialized node control units are developed,which utilize STM32 microcontroller as the processing unit.Further,a distributed control system is constructed based on multi-processor collaboration.Building on this foundation,a large-scale active vibration control experimental platform is established.Based on the platform,experiments are carried out,involving the 4-input 4-output system and the 8-input 8-output system.The experimental results demonstrate that under steady-state harmonic excitation,the proposed algorithm not only ensures control effectiveness but also reduces computational complexity by 50%,exhibiting faster convergence speed compared with traditional centralized algorithms.Under time-varying external excitation,the proposed algorithm demonstrates rapid tracking of vibration changes,with vibration amplitudes at all controlled points declining by over 94%,proving the strong robustness and adaptive capability of the algorithm.
基金supported by the National Key R&D Program of China (No. 2022YFA1004703)the National Natural Science Foundation of China (Nos. 62122083 and 62103014)Chinese Academy of Sciences Youth Innovation Promotion Association (No. 2021003)。
文摘In this paper, the attitude tracking and load relief control problems against wind disturbances and uncertain aerodynamics as well as the engine thrust of launch vehicles are studied.Firstly, a framework of Compensated Acceleration Feedback based Active Disturbance Rejection Control(CAF-ADRC) is established to achieve both desired attitude tracking and load relief performances. In particular, the total disturbance that includes the effects caused by both aerocoefficient perturbations and disturbances is estimated by constructing an Extended State Observer(ESO) to achieve attitude tracking. Furthermore, combined with the normal acceleration due to the engine thrust, the accelerometer measurement is also compensated to enhance the load relief effect.Secondly, the quantitative analysis of ESO and the entire closed-loop system are studied. It can be concluded that the desired attitude tracking and load relief performances can be achieved simultaneously under the proposed approach. Besides, tuning laws of the proposed approach are systematically given, which are divided into ESO, Proportional Derivative(PD) and Compensated Acceleration Feedback(CAF) modules. Moreover, the performances under CAF-ADRC approach can be better than those under CAF based PD(CAF-PD) approach by tuning load relief gain.Finally, the approach presented is applied to a typical control problem of launch vehicles with wind disturbances and parameter uncertainties.
基金Supported by National Natural Science Foundation of China(Grant Nos.51975037,52375075).
文摘This paper proposes a modified iterative learning control(MILC)periodical feedback-feedforward algorithm to reduce the vibration of a rotor caused by coupled unbalance and parallel misalignment.The control of the vibration of the rotor is provided by an active magnetic actuator(AMA).The iterative gain of the MILC algorithm here presented has a self-adjustment based on the magnitude of the vibration.Notch filters are adopted to extract the synchronous(1×Ω)and twice rotational frequency(2×Ω)components of the rotor vibration.Both the notch frequency of the filter and the size of feedforward storage used during the experiment have a real-time adaptation to the rotational speed.The method proposed in this work can provide effective suppression of the vibration of the rotor in case of sudden changes or fluctuations of the rotor speed.Simulations and experiments using the MILC algorithm proposed here are carried out and give evidence to the feasibility and robustness of the technique proposed.
文摘This paper addresses the sampled-data multi-objective active suspension control problem for an in-wheel motor driven electric vehicle subject to stochastic sampling periods and asynchronous premise variables.The focus is placed on the scenario that the dynamical state of the half-vehicle active suspension system is transmitted over an in-vehicle controller area network that only permits the transmission of sampled data packets.For this purpose,a stochastic sampling mechanism is developed such that the sampling periods can randomly switch among different values with certain mathematical probabilities.Then,an asynchronous fuzzy sampled-data controller,featuring distinct premise variables from the active suspension system,is constructed to eliminate the stringent requirement that the sampled-data controller has to share the same grades of membership.Furthermore,novel criteria for both stability analysis and controller design are derived in order to guarantee that the resultant closed-loop active suspension system is stochastically stable with simultaneous𝐻2 and𝐻∞performance requirements.Finally,the effectiveness of the proposed stochastic sampled-data multi-objective control method is verified via several numerical cases studies in both time domain and frequency domain under various road disturbance profiles.
文摘Addressing issues such as the disconnect between theory and practice and low student engagement in control system education,this paper uses the course“The Working Process of Open-Loop Control Systems”as a case study to explore the integration of AI technology with the“project-guided and task-driven”teaching model.By constructing a four-dimensional teaching framework of“situation-task-activity-evaluation,”AI tools are embedded in project practices such as the construction of a mechanical timed flower watering device and the optimization of a digital timed flower watering device,achieving precision,interactivity,and personalization in the teaching process.Teaching practice demonstrates that this model significantly enhances students’technical awareness,materialization capabilities,and engineering thinking,providing a reference for the teaching reform of technical courses in high school education.
基金supported by the Lanzhou Jiaotong University-Southwest Jiaotong University Joint Innovation Fund(LH2024027).
文摘The virtual synchronous generator(VSG)technology has been proposed to address the problem of system frequency and active power oscillation caused by grid-connected new energy power sources.However,the traditional voltage-current double-closed-loop control used in VSG has the disadvantages of poor disturbance immunity and insufficient dynamic response.In light of the issues above,a virtual synchronous generator voltage outer-loop control strategy based on improved linear autonomous disturbance rejection control(ILADRC)is put forth for consideration.Firstly,an improved first-order linear self-immunity control structure is established for the characteristics of the voltage outer loop;then,the effects of two key control parameters-observer bandwidthω_(0)and controller bandwidthω_(c)on the control system are analyzed,and the key parameters of ILADRC are optimally tuned online using improved gray wolf optimizer-radial basis function(IGWO-RBF)neural network.A simulationmodel is developed using MATLAB to simulate,analyze,and compare the method introduced in this paper.Simulations are performed with the traditional control strategy for comparison,and the results demonstrate that the proposed control method offers superior anti-interference performance.It effectively addresses power and frequency oscillation issues and enhances the stability of the VSG during grid-connected operation.
基金supported in part by the National Natural Science Foundation of China under Grant No.62172280in part by the Key Scientific Research Projects of Colleges and Universities in Henan Province,China under Grant No.23A520006in part by Henan Provincial Science and Technology Research Project under Grant No.222102210199.
文摘Deep neural network(DNN)models have achieved remarkable performance across diverse tasks,leading to widespread commercial adoption.However,training high-accuracy models demands extensive data,substantial computational resources,and significant time investment,making them valuable assets vulnerable to unauthorized exploitation.To address this issue,this paper proposes an intellectual property(IP)protection framework for DNN models based on feature layer selection and hyper-chaotic mapping.Firstly,a sensitivity-based importance evaluation algorithm is used to identify the key feature layers for encryption,effectively protecting the core components of the model.Next,the L1 regularization criterion is applied to further select high-weight features that significantly impact the model’s performance,ensuring that the encryption process minimizes performance loss.Finally,a dual-layer encryption mechanism is designed,introducing perturbations into the weight values and utilizing hyperchaotic mapping to disrupt channel information,further enhancing the model’s security.Experimental results demonstrate that encrypting only a small subset of parameters effectively reduces model accuracy to random-guessing levels while ensuring full recoverability.The scheme exhibits strong robustness against model pruning and fine-tuning attacks and maintains consistent performance across multiple datasets,providing an efficient and practical solution for authorization-based DNN IP protection.
