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
A modified method of design of no-steady-error and anti-disturbance controller is proposed for the design of tank stabilizers. Using a reduced-order observer to estimate its mode, disturbance can be compensated. This ...A modified method of design of no-steady-error and anti-disturbance controller is proposed for the design of tank stabilizers. Using a reduced-order observer to estimate its mode, disturbance can be compensated. This enables the system to resist sinusoidal disturbance with any magnitude. Estimate of angular velocity is used as the state feedback to replace the expensive gyro and tachometer generator. The modified method excels the traditional, and provides a new way for the design of tank fire control system. It can also be applied for the design of other servo systems in vehicle and aircraft.展开更多
In this paper, we propose a novel anti-disturbance attitude control law for combined spacecraft with an improved closed-loop control allocation scheme. More specifically, a saturated approach is adopted to guarantee t...In this paper, we propose a novel anti-disturbance attitude control law for combined spacecraft with an improved closed-loop control allocation scheme. More specifically, a saturated approach is adopted to guarantee the global asymptotic stability under control input saturation.To enhance the robustness of the system, a nonlinear disturbance observer is constructed to compensate the disturbances caused by inertial parameter uncertainty and unmodeled dynamics. Next,the quadratic programming algorithm is used to obtain an optimal open-loop control allocation scheme, where both energy consumption and actuator saturation have been considered in the allocation of the virtual control command. Then, a modified closed-loop control allocation scheme is proposed to reduce the allocation error under the actuator uncertainty. Finally, stability analysis of the closed-loop system with the proposed allocation scheme is provided. Simulation results confirm the effectiveness of the proposed control scheme.展开更多
The rendezvous and proximity operations with respect to a tumbling non-cooperative target pose high requirement for the position and attitude control accuracy of servicing spacecraft.However,multiple disturbances incl...The rendezvous and proximity operations with respect to a tumbling non-cooperative target pose high requirement for the position and attitude control accuracy of servicing spacecraft.However,multiple disturbances including parametric uncertainties,flexible vibration,and unknown nonlinear dynamics degrade the control performance significantly.In order to enhance the system anti-disturbance ability,this paper proposes a composite anti-disturbance control law for the spacecraft position and attitude tracking.Firstly,the relative position and attitude dynamic models with multiple disturbances are established,where the refined descriptions of multiple disturbances are accomplished based on their characteristics.Then,by combining a dual Disturbance ObserverBased Control(DOBC)and a sliding mode control,a composite controller with hierarchical architecture is proposed,where the dual DOBC in the feedforward channel is used to reject the flexible vibration,environment disturbance,and complicated nonlinear dynamics,while the parametric uncertainties are attenuated by the sliding mode control in the feedback channel.Stability analysis is carried out for the closed-loop system by unifying the sliding mode dynamics and observer dynamics.Finally,the effectiveness of the proposed controller is verified via numerical simulation and hardware-in-the-loop test.展开更多
In this paper,we investigate the peaking issue of extended state observers and the anti-disturbance control problem of tethered aircraft systems subject to the unstable flight of the main aircraft,airflow disturbances...In this paper,we investigate the peaking issue of extended state observers and the anti-disturbance control problem of tethered aircraft systems subject to the unstable flight of the main aircraft,airflow disturbances and deferred output constraints.Independent of exact initial values,a modified extended state observer is constructed from a shifting function such that not only the peaking issue inherently in the observer is circumvented completely but also the accurate estimation of the lumped disturbance is guaranteed.Meanwhile,to deal with deferred output constraints,an improved output constrained controller is employed by integrating the shifting function into the barrier Lyapunov function.Then,by combining the modified observer and the improved controller,an anti-disturbance control scheme is presented,which ensures that the outputs with any bounded initial conditions satisfy the constraints after a pre-specified finite time,and the tethered aircraft tracks the desired trajectory accurately.Finally,both a theoretical proof and simulation results verify the effectiveness of the proposed control scheme.展开更多
This paper introduces the function, structure and alarm principles of the breakout prediction system installed for continuous casting in Baosteel＇ s No. 2 Steelmaking Plant. It elaborates on four parameters in the al...This paper introduces the function, structure and alarm principles of the breakout prediction system installed for continuous casting in Baosteel＇ s No. 2 Steelmaking Plant. It elaborates on four parameters in the alarm logic,including the temperature changing rate, temperature difference, temperature fluctuation and temperature match of thermocouples. This paper also explains the causes of different disturbances within the breakout prediction system, and the methods used to prevent and eliminate disturbances from radiation, earth, crosstalk, temperature drift and time drift. Finally, the paper summarizes some potential applications of the above technology.展开更多
The growing interest in biological skin mimicry has greatly contributed to the creation of high-performance artificial skin.Here,inspired by the optical-electrical signal co-transmission of chameleon skins,a bilayer b...The growing interest in biological skin mimicry has greatly contributed to the creation of high-performance artificial skin.Here,inspired by the optical-electrical signal co-transmission of chameleon skins,a bilayer biomimetic ion-conductive photoelectronic skin(BIPES)was constructed by compositing the mechanochromic nano-structured silica photonic crystal film with an adhesive,flexible hydrogel by a layer-by-layer design strategy.The BIPES has a highly sensitive strain response on electrical and optical signals(GF=3.27 at 0-100%,△λ/△ε=2.1 nm%^(-1))and temperature response(TCR=-2.27%℃^(-1)at 0-50℃).Importantly,through the temperature insensitivity of the mechanochromic film,the BIPES not only achieved dual-signal motion detection but also achieved real-time temperature monitoring excluding strain interference.This research provides new inspiration for the construction of multi-signal combined photoelectronic skins and further exploration for advanced accurate smart wearable electronics in appli-cations,especially in health detection for patients with non-spontaneous body-trembling.展开更多
The significance of detection of urban active faults and the general situation concerning detection of urban active faults in the world are briefly introduced. In a brief description of the basic principles of anti-di...The significance of detection of urban active faults and the general situation concerning detection of urban active faults in the world are briefly introduced. In a brief description of the basic principles of anti-disturbance and high-resolution shallow seismic exploration, the stress is put on the excitation of seismic sources, the performance of digital seismographs, receiving mode and conditions, geometry as well as data acquisition, processing and interpretation in the anti-disturbance and high-resolution shallow seismic exploration of urban active faults. The study indicates that a controlled seismic source with a linear or nonlinear frequency-conversion scanning function and the relevant seismographs must be used in data acquisition, as well as working methods for small group interval, small offset, multi-channel receiving, short-array and high-frequency detectors for receiving are used. Attention should be paid to the application of techniques for static correction of refraction, noise suppressing, high-precision analysis of velocity, wavelet compressing, zero-phasing of wavelet and pre-stacking migration to data processing and interpretation. Finally, some cases of anti-disturbance and high-resolution shallow seismic exploration of urban active faults are present in the paper.展开更多
In this paper,an adaptive composite anti-disturbance control of heavy haul trains(HHTs)is proposed.First,the mechanical principle and characteristics of couplers are analysed and the longitudinal multi-particles nonli...In this paper,an adaptive composite anti-disturbance control of heavy haul trains(HHTs)is proposed.First,the mechanical principle and characteristics of couplers are analysed and the longitudinal multi-particles nonlinear dynamic model of HHTs is established,which can satisfy that the forces of vehicles in different positions are different.Subsequently,a radial basis function network(RBFNN)is employed to approximate the uncertainties of HHTs,and a nonlinear disturbance observer(NDO)is constructed to estimate the approximation error and external disturbances.To indicate and improve the approximation accuracy,a serial-parallel identification model of HHTs is constructed to generate a prediction error,and an adaptive composite anti-disturbance control scheme is developed,where the prediction error and tracking error are employed to update RBFNN weights and an auxiliary variable of NDO.Finally,the feasibility and effectiveness of the proposed control scheme are demonstrated through the Lyapunov theory and simulation experiments.展开更多
A 13bit,pipelined analog-to-digital converter （ADC） designed to achieve high linearity is described. The high linearity is realized by using the passive capacitor error-averaging technique to calibrate the capacitor...A 13bit,pipelined analog-to-digital converter （ADC） designed to achieve high linearity is described. The high linearity is realized by using the passive capacitor error-averaging technique to calibrate the capacitor mismatch error, a gain-boosting opamp to minimize the finite gain error and gain nonlinearity,a bootstrapping switch to reduce the switch on-resistor nonlinearity, and an anti-disturb design to reduce the noise from the digital supply. This ADC is implemented in 0.18μm CMOS technology and occupies a die area of 3.2mm^2 , including pads. Measured performance includes - 0.18/ 0.15LSB of differential nonlinearity, -0.35/0.5LSB of integral nonlinearity, 75.7dB of signal-to-noise plus distortion ratio （SNDR） and 90. 5 dBc of spurious-free dynamic range （SFDR） for 2.4MHz input at 2.5MS/s. At full speed conversion （5MS/s） and for the same 2.4MHz input, the measured SNDR and SFDR are 73.7dB and 83.9 dBc, respectively. The power dissipation including output pad drivers is 21mW at 2.5MS/s and 34mW at 5MS/s,both at 2.7V supply.展开更多
Various force disturbances influence the thrust force of linear motors when a linear motor （LM） is running. Among all of force disturbances, the force ripple is the dominant while a linear motor runs in low speed. I...Various force disturbances influence the thrust force of linear motors when a linear motor （LM） is running. Among all of force disturbances, the force ripple is the dominant while a linear motor runs in low speed. In order to suppress the force ripple, back propagation（BP） neural network is proposed to learn the function of the force ripple of linear motors, and the acquisition method of training samples is proposed based on a disturbance observer. An off-line BP neural network is used mainly because of its high running efficiency and the real-time requirement of the servo control system of a linear motor. By using the function, the force ripple is on-line compensated according to the position of the LM. The experimental results show that the force ripple is effectively suppressed by the compensation of the BP neural network.展开更多
This paper investigates the event-triggered security consensus problem for nonlinear multi-agent systems(MASs)under denial-of-service(Do S)attacks over an undirected graph.A novel adaptive memory observer-based anti-d...This paper investigates the event-triggered security consensus problem for nonlinear multi-agent systems(MASs)under denial-of-service(Do S)attacks over an undirected graph.A novel adaptive memory observer-based anti-disturbance control scheme is presented to improve the observer accuracy by adding a buffer for the system output measurements.Meanwhile,this control scheme can also provide more reasonable control signals when Do S attacks occur.To save network resources,an adaptive memory event-triggered mechanism(AMETM)is also proposed and Zeno behavior is excluded.It is worth mentioning that the AMETM's updates do not require global information.Then,the observer and controller gains are obtained by using the linear matrix inequality(LMI)technique.Finally,simulation examples show the effectiveness of the proposed control scheme.展开更多
Track tension is a major factor influencing the reliability of a track.In order to reduce the risk of track peel-off,it is necessary to keep track tension constant.However,it is difficult to measure the dynamic tensio...Track tension is a major factor influencing the reliability of a track.In order to reduce the risk of track peel-off,it is necessary to keep track tension constant.However,it is difficult to measure the dynamic tension during off-road operation.Based on the analysis of the relation and external forces depending on free body diagrams of the idler,idler arm,road wheel and road arm,a theoretical estimation model of track tension is built.Comparing estimation results with multibody dynamics simulation results,the rationality of track tension monitor is validated.By the aid of this monitor,a track tension control system is designed,which includes a self-tuning proportional-integral-derivative(PID)controller based on radial basis function neural network,an electro-hydraulic servo system and an idler arm.The tightness of track can be adjusted by turning the idler arm.Simulation results of the vehicle starting process indicate that the controller can reach different expected tensions quickly and accurately.Compared with a traditional PID controller,the proposed controller has a stronger anti-disturbance ability by amending control parameters online.展开更多
The fault diagnosis problem is investigated for a class of nonlinear neutral systems with multiple disturbances.Time-varying faults are considered and multiple disturbances are supposed to include the unknown disturba...The fault diagnosis problem is investigated for a class of nonlinear neutral systems with multiple disturbances.Time-varying faults are considered and multiple disturbances are supposed to include the unknown disturbance modeled by an exo-system and norm bounded uncertain disturbance.A nonlinear disturbance observer is designed to estimate the modeled disturbance.Then,the fault diagnosis observer is constructed by integrating disturbance observer with disturbance attenuation and rejection performances.The augmented Lyapunov functional approach,which involves the tuning parameter and slack variable,is applied to make the solution of inequality more flexible.Finally,applications for a two-link robotic manipulator system are given to show the efficiency of the proposed approach.展开更多
Permanent magnet synchronous motor(PMSM)speed control systems with conventional linear active disturbance rejection control(CLADRC)strategy encounter issues regarding the coupling between dynamic response and disturba...Permanent magnet synchronous motor(PMSM)speed control systems with conventional linear active disturbance rejection control(CLADRC)strategy encounter issues regarding the coupling between dynamic response and disturbance suppression and have poor performance in suppressing complex nonlinear disturbances.In order to address these issues,this paper proposes an improved two-degree-of-freedom LADRC(TDOF-LADRC)strategy,which can enhance the disturbance rejection performance of the system while decoupling entirely the system's dynamic and anti-disturbance performance to boost the system robustness and simplify controller parameter tuning.PMSM models that consider total disturbances are developed to design the TDOF-LADRC speed controller accurately.Moreover,to evaluate the control performance of the TDOF-LADRC strategy,its stability is proven,and the influence of each controller parameter on the system control performance is analyzed.Based on it,a comparison is made between the disturbance observation ability and anti-disturbance performance of TDOF-LADRC and CLADRC to prove the superiority of TDOF-LADRC in rejecting disturbances.Finally,experiments are performed on a 750 W PMSM experimental platform,and the results demonstrate that the proposed TDOF-LADRC exhibits the properties of two degrees of freedom and improves the disturbance rejection performance of the PMSM system.展开更多
In the past few decades,people have been trying to address the issue of walking instability in bipedal robots in uncertain environments.However,most control methods currently have still failed to achieve robust walkin...In the past few decades,people have been trying to address the issue of walking instability in bipedal robots in uncertain environments.However,most control methods currently have still failed to achieve robust walking of bipedal robots under uncertain disturbances.Existing research mostly focuses on motion control methods for robots on uneven terrain and under sudden impact forces,with little consideration for the problem of continuous and intense external force disturbances in uncertain environments.In response to this issue,a disturbance-robust control method based on adaptive feedback compensation is proposed.First,based on the Lagrangian method,the dynamic model of a bipedal robot under different types of external force disturbances was established.Subsequently,through dynamic analysis,it was observed that classical control methods based on hybrid zero dynamics failed to consider the continuous and significant external force disturbances in uncertain environments.Therefore,an adaptive feedback compensation controller was designed,and an adaptive parameter adjustment optimization algorithm was proposed based on walking constraints to achieve stable walking of bipedal robots under different external force disturbances.Finally,in numerical simulation experiments,comparative analysis revealed that using only a controller based on hybrid zero dynamics was insufficient to converge the motion of a planar five-link bipedal robot subjected to periodic forces or bounded noise disturbances to a stable state.In contrast,in the adaptive feedback compensation control method,the use of an adaptive parameter adjustment optimization algorithm to generate time-varying control parameters successfully achieved stable walking of the robot under these disturbances.This indicates the effectiveness of the adaptive parameter adjustment algorithm and the robustness of the adaptive feedback compensation control method.展开更多
The focus of this paper is on distributed average tracking(DAT)in the context of external disturbances,utilizing an event-triggered control mechanism.First,an event-triggered anti-disturbance DAT(ETAD-DAT)algorithm is...The focus of this paper is on distributed average tracking(DAT)in the context of external disturbances,utilizing an event-triggered control mechanism.First,an event-triggered anti-disturbance DAT(ETAD-DAT)algorithm is proposed to reduce communication load in networked control systems by redesigning existing anti-disturbance DAT algorithms and disturbance observers.Furthermore,a fully distributed event-triggering condition is employed to schedule event times for each agent.Simulation results demonstrate that the proposed ETAD-DAT algorithm is able to achieve accurate average tracking of multiple time-varying reference signals despite the presence of external disturbances,while the communication efficiency can be improved obviously.展开更多
Finite-time stabilisation is studied for a class of nonlinear systems subject to multiple disturbances,in which,the disturbances are divided into two classes,one is the disturbance with partly known information,anothe...Finite-time stabilisation is studied for a class of nonlinear systems subject to multiple disturbances,in which,the disturbances are divided into two classes,one is the disturbance with partly known information,another is uncertain bounded disturbances.The first one is estimated by constructing an adaptive disturbance observer(ADO),the unknown nonlinear function is approximated by the fuzzy logic systems.Then a finite-time composite controller is constructed by incorporating the disturbance observer-based control(DOBC)with the finite-time stability theory,under which the system state tends to be stable within a finite time.Eventually,the manoeuvrability and validity of the presented tactics are verified by simulation examples.展开更多
This paper addresses the problem of composite inverse optimal control for a class of uncertain nonlinear systems affected by unmatched disturbances.A control framework is proposed by integrating a generalized proporti...This paper addresses the problem of composite inverse optimal control for a class of uncertain nonlinear systems affected by unmatched disturbances.A control framework is proposed by integrating a generalized proportional integral observer(GPIO)with a neural network based scheme to simultaneously estimate both matched and mismatched disturbances and to approximate unknown system nonlinearities.To overcome the computational challenges associated with solving the nonlinear Hamilton-Jacobi-Bellman(HJB)equation in highorder systems,a composite adaptive inverse optimal control(IOC)strategy is developed.This approach combines GPIOs with the IOC framework,effectively utilizing the available system information while providing adaptive capability in dynamically changing environments.A rigorous theoretical analysis is presented to guarantee both stability and optimality of closed-loop system.The effectiveness and robustness of the proposed method are demonstrated through simulation studies.展开更多
In this paper,the effect of disturbances on the operation process of a methane-fueled free-piston engine generator(FPEG)was experimentally investigated.Four disturbance sources,namely step change of external load,mixt...In this paper,the effect of disturbances on the operation process of a methane-fueled free-piston engine generator(FPEG)was experimentally investigated.Four disturbance sources,namely step change of external load,mixture flow rate fluctuation,random misfire of a cylinder,and elastic collision,were identified and applied to the FPEG.The results showed that the FPEG successfully achieved a steady-state operation with load.The maximum instantaneous electric power of 127 W and the average effective electric power of 38.9 W were obtained.When an external load was instantaneously disconnected,the engine frequency increased from 26.7 Hz to 31.3 Hz.The fluctuation amplitudes of induced voltage,pressure and compression ratio were 18.9%,24.7%and 52.2%respectively in the disturbance.By contrast,when the external load was instantaneously connected,the corresponding values were 42.2%,31.3%and 64.3%respectively,indicating that the instantaneous external load connection had a greater disturbance impact on the FPEG operation stability.Despite encountering the step change of external load,the FPEG can still restore stable operation and show good anti-disturbance ability.Compared with increasing mixture flow rate,reducing the mixture flow rate has a greater disturbance impact on the engine operation stability.Although random misfire of a cylinder will cause remarkable fluctuations in piston displacement and cylinder pressure,the FPEG will not stop running,but continues to work as a single-piston engine.Minor collision event may adversely affect the stability of engine operation,but will not lead to the FPEG shutdown.However,serious collision event may lead to ignition failure and shutdown accident.展开更多
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.
文摘A modified method of design of no-steady-error and anti-disturbance controller is proposed for the design of tank stabilizers. Using a reduced-order observer to estimate its mode, disturbance can be compensated. This enables the system to resist sinusoidal disturbance with any magnitude. Estimate of angular velocity is used as the state feedback to replace the expensive gyro and tachometer generator. The modified method excels the traditional, and provides a new way for the design of tank fire control system. It can also be applied for the design of other servo systems in vehicle and aircraft.
基金co-supported by the National Natural Science Foundation of China (Nos. 61627810, 61320106010, 61633003, 61661136007, 61603021)the Program for Changjiang Scholars and Innovative Research Team (No. IRT_16R03)Innovative Research Team of National Natural Science Foundation of China (No. 61421063)
文摘In this paper, we propose a novel anti-disturbance attitude control law for combined spacecraft with an improved closed-loop control allocation scheme. More specifically, a saturated approach is adopted to guarantee the global asymptotic stability under control input saturation.To enhance the robustness of the system, a nonlinear disturbance observer is constructed to compensate the disturbances caused by inertial parameter uncertainty and unmodeled dynamics. Next,the quadratic programming algorithm is used to obtain an optimal open-loop control allocation scheme, where both energy consumption and actuator saturation have been considered in the allocation of the virtual control command. Then, a modified closed-loop control allocation scheme is proposed to reduce the allocation error under the actuator uncertainty. Finally, stability analysis of the closed-loop system with the proposed allocation scheme is provided. Simulation results confirm the effectiveness of the proposed control scheme.
基金supported by the China National Postdoctoral Program for Innovative Talents(No.BX20200031)the National Natural Science Foundation of China(Nos.62103013,61633003,61973012)the Program for Changjiang Scholars and Innovative Research Team,China(No.IRT 16R03).
文摘The rendezvous and proximity operations with respect to a tumbling non-cooperative target pose high requirement for the position and attitude control accuracy of servicing spacecraft.However,multiple disturbances including parametric uncertainties,flexible vibration,and unknown nonlinear dynamics degrade the control performance significantly.In order to enhance the system anti-disturbance ability,this paper proposes a composite anti-disturbance control law for the spacecraft position and attitude tracking.Firstly,the relative position and attitude dynamic models with multiple disturbances are established,where the refined descriptions of multiple disturbances are accomplished based on their characteristics.Then,by combining a dual Disturbance ObserverBased Control(DOBC)and a sliding mode control,a composite controller with hierarchical architecture is proposed,where the dual DOBC in the feedforward channel is used to reject the flexible vibration,environment disturbance,and complicated nonlinear dynamics,while the parametric uncertainties are attenuated by the sliding mode control in the feedback channel.Stability analysis is carried out for the closed-loop system by unifying the sliding mode dynamics and observer dynamics.Finally,the effectiveness of the proposed controller is verified via numerical simulation and hardware-in-the-loop test.
基金supported by the National Natural Science Foundation of China(61725303,91848205)。
文摘In this paper,we investigate the peaking issue of extended state observers and the anti-disturbance control problem of tethered aircraft systems subject to the unstable flight of the main aircraft,airflow disturbances and deferred output constraints.Independent of exact initial values,a modified extended state observer is constructed from a shifting function such that not only the peaking issue inherently in the observer is circumvented completely but also the accurate estimation of the lumped disturbance is guaranteed.Meanwhile,to deal with deferred output constraints,an improved output constrained controller is employed by integrating the shifting function into the barrier Lyapunov function.Then,by combining the modified observer and the improved controller,an anti-disturbance control scheme is presented,which ensures that the outputs with any bounded initial conditions satisfy the constraints after a pre-specified finite time,and the tethered aircraft tracks the desired trajectory accurately.Finally,both a theoretical proof and simulation results verify the effectiveness of the proposed control scheme.
文摘This paper introduces the function, structure and alarm principles of the breakout prediction system installed for continuous casting in Baosteel＇ s No. 2 Steelmaking Plant. It elaborates on four parameters in the alarm logic,including the temperature changing rate, temperature difference, temperature fluctuation and temperature match of thermocouples. This paper also explains the causes of different disturbances within the breakout prediction system, and the methods used to prevent and eliminate disturbances from radiation, earth, crosstalk, temperature drift and time drift. Finally, the paper summarizes some potential applications of the above technology.
基金financially supported by the National Natural Science Foundation of China(No.82172040).
文摘The growing interest in biological skin mimicry has greatly contributed to the creation of high-performance artificial skin.Here,inspired by the optical-electrical signal co-transmission of chameleon skins,a bilayer biomimetic ion-conductive photoelectronic skin(BIPES)was constructed by compositing the mechanochromic nano-structured silica photonic crystal film with an adhesive,flexible hydrogel by a layer-by-layer design strategy.The BIPES has a highly sensitive strain response on electrical and optical signals(GF=3.27 at 0-100%,△λ/△ε=2.1 nm%^(-1))and temperature response(TCR=-2.27%℃^(-1)at 0-50℃).Importantly,through the temperature insensitivity of the mechanochromic film,the BIPES not only achieved dual-signal motion detection but also achieved real-time temperature monitoring excluding strain interference.This research provides new inspiration for the construction of multi-signal combined photoelectronic skins and further exploration for advanced accurate smart wearable electronics in appli-cations,especially in health detection for patients with non-spontaneous body-trembling.
文摘The significance of detection of urban active faults and the general situation concerning detection of urban active faults in the world are briefly introduced. In a brief description of the basic principles of anti-disturbance and high-resolution shallow seismic exploration, the stress is put on the excitation of seismic sources, the performance of digital seismographs, receiving mode and conditions, geometry as well as data acquisition, processing and interpretation in the anti-disturbance and high-resolution shallow seismic exploration of urban active faults. The study indicates that a controlled seismic source with a linear or nonlinear frequency-conversion scanning function and the relevant seismographs must be used in data acquisition, as well as working methods for small group interval, small offset, multi-channel receiving, short-array and high-frequency detectors for receiving are used. Attention should be paid to the application of techniques for static correction of refraction, noise suppressing, high-precision analysis of velocity, wavelet compressing, zero-phasing of wavelet and pre-stacking migration to data processing and interpretation. Finally, some cases of anti-disturbance and high-resolution shallow seismic exploration of urban active faults are present in the paper.
基金This research was supported by the National Natural Science Foundation of China(Grants No.U2034211 and 61963029)the Jiangxi Provincial Natural Science Foundation(Grants No.20232ACE01013 and 20232ACB202007)。
文摘In this paper,an adaptive composite anti-disturbance control of heavy haul trains(HHTs)is proposed.First,the mechanical principle and characteristics of couplers are analysed and the longitudinal multi-particles nonlinear dynamic model of HHTs is established,which can satisfy that the forces of vehicles in different positions are different.Subsequently,a radial basis function network(RBFNN)is employed to approximate the uncertainties of HHTs,and a nonlinear disturbance observer(NDO)is constructed to estimate the approximation error and external disturbances.To indicate and improve the approximation accuracy,a serial-parallel identification model of HHTs is constructed to generate a prediction error,and an adaptive composite anti-disturbance control scheme is developed,where the prediction error and tracking error are employed to update RBFNN weights and an auxiliary variable of NDO.Finally,the feasibility and effectiveness of the proposed control scheme are demonstrated through the Lyapunov theory and simulation experiments.
文摘A 13bit,pipelined analog-to-digital converter （ADC） designed to achieve high linearity is described. The high linearity is realized by using the passive capacitor error-averaging technique to calibrate the capacitor mismatch error, a gain-boosting opamp to minimize the finite gain error and gain nonlinearity,a bootstrapping switch to reduce the switch on-resistor nonlinearity, and an anti-disturb design to reduce the noise from the digital supply. This ADC is implemented in 0.18μm CMOS technology and occupies a die area of 3.2mm^2 , including pads. Measured performance includes - 0.18/ 0.15LSB of differential nonlinearity, -0.35/0.5LSB of integral nonlinearity, 75.7dB of signal-to-noise plus distortion ratio （SNDR） and 90. 5 dBc of spurious-free dynamic range （SFDR） for 2.4MHz input at 2.5MS/s. At full speed conversion （5MS/s） and for the same 2.4MHz input, the measured SNDR and SFDR are 73.7dB and 83.9 dBc, respectively. The power dissipation including output pad drivers is 21mW at 2.5MS/s and 34mW at 5MS/s,both at 2.7V supply.
基金National Natural Science Foundation of China(No. 60474021)
文摘Various force disturbances influence the thrust force of linear motors when a linear motor （LM） is running. Among all of force disturbances, the force ripple is the dominant while a linear motor runs in low speed. In order to suppress the force ripple, back propagation（BP） neural network is proposed to learn the function of the force ripple of linear motors, and the acquisition method of training samples is proposed based on a disturbance observer. An off-line BP neural network is used mainly because of its high running efficiency and the real-time requirement of the servo control system of a linear motor. By using the function, the force ripple is on-line compensated according to the position of the LM. The experimental results show that the force ripple is effectively suppressed by the compensation of the BP neural network.
基金supported by the National Natural Science Foundation of China(61773056)the Scientific and Technological Innovation Foundation of Shunde Graduate School,University of Science and Technology Beijing(USTB)(BK19AE018)+2 种基金the Fundamental Research Funds for the Central Universities of USTB(FRF-TP-20-09B,230201606500061,FRF-DF-20-35,FRF-BD-19-002A)supported by Zhejiang Natural Science Foundation(LD21F030001)supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(Ministry of Science and Information and Communications Technology)(NRF-2020R1A2C1005449)。
文摘This paper investigates the event-triggered security consensus problem for nonlinear multi-agent systems(MASs)under denial-of-service(Do S)attacks over an undirected graph.A novel adaptive memory observer-based anti-disturbance control scheme is presented to improve the observer accuracy by adding a buffer for the system output measurements.Meanwhile,this control scheme can also provide more reasonable control signals when Do S attacks occur.To save network resources,an adaptive memory event-triggered mechanism(AMETM)is also proposed and Zeno behavior is excluded.It is worth mentioning that the AMETM's updates do not require global information.Then,the observer and controller gains are obtained by using the linear matrix inequality(LMI)technique.Finally,simulation examples show the effectiveness of the proposed control scheme.
基金The authors gratefully acknowledge the Natural Science Foundation of Jiangsu Province(No.BK20190871)Natural Science Foundation of Jiangsu Province(No.BK20190438)for the financial support of this research.
文摘Track tension is a major factor influencing the reliability of a track.In order to reduce the risk of track peel-off,it is necessary to keep track tension constant.However,it is difficult to measure the dynamic tension during off-road operation.Based on the analysis of the relation and external forces depending on free body diagrams of the idler,idler arm,road wheel and road arm,a theoretical estimation model of track tension is built.Comparing estimation results with multibody dynamics simulation results,the rationality of track tension monitor is validated.By the aid of this monitor,a track tension control system is designed,which includes a self-tuning proportional-integral-derivative(PID)controller based on radial basis function neural network,an electro-hydraulic servo system and an idler arm.The tightness of track can be adjusted by turning the idler arm.Simulation results of the vehicle starting process indicate that the controller can reach different expected tensions quickly and accurately.Compared with a traditional PID controller,the proposed controller has a stronger anti-disturbance ability by amending control parameters online.
基金supported by the National Natural Science Foundation of China(6077401360925012)+1 种基金the National High Technology Research and Development Program of China(863 Program) (2008AA12A216)the National Basic Research Program of China (973 Program)(2009CB 724002)
文摘The fault diagnosis problem is investigated for a class of nonlinear neutral systems with multiple disturbances.Time-varying faults are considered and multiple disturbances are supposed to include the unknown disturbance modeled by an exo-system and norm bounded uncertain disturbance.A nonlinear disturbance observer is designed to estimate the modeled disturbance.Then,the fault diagnosis observer is constructed by integrating disturbance observer with disturbance attenuation and rejection performances.The augmented Lyapunov functional approach,which involves the tuning parameter and slack variable,is applied to make the solution of inequality more flexible.Finally,applications for a two-link robotic manipulator system are given to show the efficiency of the proposed approach.
文摘Permanent magnet synchronous motor(PMSM)speed control systems with conventional linear active disturbance rejection control(CLADRC)strategy encounter issues regarding the coupling between dynamic response and disturbance suppression and have poor performance in suppressing complex nonlinear disturbances.In order to address these issues,this paper proposes an improved two-degree-of-freedom LADRC(TDOF-LADRC)strategy,which can enhance the disturbance rejection performance of the system while decoupling entirely the system's dynamic and anti-disturbance performance to boost the system robustness and simplify controller parameter tuning.PMSM models that consider total disturbances are developed to design the TDOF-LADRC speed controller accurately.Moreover,to evaluate the control performance of the TDOF-LADRC strategy,its stability is proven,and the influence of each controller parameter on the system control performance is analyzed.Based on it,a comparison is made between the disturbance observation ability and anti-disturbance performance of TDOF-LADRC and CLADRC to prove the superiority of TDOF-LADRC in rejecting disturbances.Finally,experiments are performed on a 750 W PMSM experimental platform,and the results demonstrate that the proposed TDOF-LADRC exhibits the properties of two degrees of freedom and improves the disturbance rejection performance of the PMSM system.
基金supported by the National Natural Science Foundation of China(Grant No.12332003)CIE-Tencent Robotics X Rhino-Bird Focused Research Program,and Zhejiang Provincial Natural Science Foundation of China(Grant No.LY23E050010).
文摘In the past few decades,people have been trying to address the issue of walking instability in bipedal robots in uncertain environments.However,most control methods currently have still failed to achieve robust walking of bipedal robots under uncertain disturbances.Existing research mostly focuses on motion control methods for robots on uneven terrain and under sudden impact forces,with little consideration for the problem of continuous and intense external force disturbances in uncertain environments.In response to this issue,a disturbance-robust control method based on adaptive feedback compensation is proposed.First,based on the Lagrangian method,the dynamic model of a bipedal robot under different types of external force disturbances was established.Subsequently,through dynamic analysis,it was observed that classical control methods based on hybrid zero dynamics failed to consider the continuous and significant external force disturbances in uncertain environments.Therefore,an adaptive feedback compensation controller was designed,and an adaptive parameter adjustment optimization algorithm was proposed based on walking constraints to achieve stable walking of bipedal robots under different external force disturbances.Finally,in numerical simulation experiments,comparative analysis revealed that using only a controller based on hybrid zero dynamics was insufficient to converge the motion of a planar five-link bipedal robot subjected to periodic forces or bounded noise disturbances to a stable state.In contrast,in the adaptive feedback compensation control method,the use of an adaptive parameter adjustment optimization algorithm to generate time-varying control parameters successfully achieved stable walking of the robot under these disturbances.This indicates the effectiveness of the adaptive parameter adjustment algorithm and the robustness of the adaptive feedback compensation control method.
基金part supported by the National Natural Science Foundation(62203034,62273126,62203035)the Ling-Yan Research and Development Project of Zhejiang Province of China(2023C03185)。
文摘The focus of this paper is on distributed average tracking(DAT)in the context of external disturbances,utilizing an event-triggered control mechanism.First,an event-triggered anti-disturbance DAT(ETAD-DAT)algorithm is proposed to reduce communication load in networked control systems by redesigning existing anti-disturbance DAT algorithms and disturbance observers.Furthermore,a fully distributed event-triggering condition is employed to schedule event times for each agent.Simulation results demonstrate that the proposed ETAD-DAT algorithm is able to achieve accurate average tracking of multiple time-varying reference signals despite the presence of external disturbances,while the communication efficiency can be improved obviously.
基金supported by the National Natural Science Foundation of China(61973149,61903173)the Key project of the Natural Science Foundation of Shandong Province(ZR2020KF029).
文摘Finite-time stabilisation is studied for a class of nonlinear systems subject to multiple disturbances,in which,the disturbances are divided into two classes,one is the disturbance with partly known information,another is uncertain bounded disturbances.The first one is estimated by constructing an adaptive disturbance observer(ADO),the unknown nonlinear function is approximated by the fuzzy logic systems.Then a finite-time composite controller is constructed by incorporating the disturbance observer-based control(DOBC)with the finite-time stability theory,under which the system state tends to be stable within a finite time.Eventually,the manoeuvrability and validity of the presented tactics are verified by simulation examples.
基金supported by the National Natural Science Foundation of China(No.62025302).
文摘This paper addresses the problem of composite inverse optimal control for a class of uncertain nonlinear systems affected by unmatched disturbances.A control framework is proposed by integrating a generalized proportional integral observer(GPIO)with a neural network based scheme to simultaneously estimate both matched and mismatched disturbances and to approximate unknown system nonlinearities.To overcome the computational challenges associated with solving the nonlinear Hamilton-Jacobi-Bellman(HJB)equation in highorder systems,a composite adaptive inverse optimal control(IOC)strategy is developed.This approach combines GPIOs with the IOC framework,effectively utilizing the available system information while providing adaptive capability in dynamically changing environments.A rigorous theoretical analysis is presented to guarantee both stability and optimality of closed-loop system.The effectiveness and robustness of the proposed method are demonstrated through simulation studies.
基金supported by the National Natural Science Foundation of China(No.52076007)Project of Educational Commission of Henan Province of China(No.22A470007 and No.20A470008)。
文摘In this paper,the effect of disturbances on the operation process of a methane-fueled free-piston engine generator(FPEG)was experimentally investigated.Four disturbance sources,namely step change of external load,mixture flow rate fluctuation,random misfire of a cylinder,and elastic collision,were identified and applied to the FPEG.The results showed that the FPEG successfully achieved a steady-state operation with load.The maximum instantaneous electric power of 127 W and the average effective electric power of 38.9 W were obtained.When an external load was instantaneously disconnected,the engine frequency increased from 26.7 Hz to 31.3 Hz.The fluctuation amplitudes of induced voltage,pressure and compression ratio were 18.9%,24.7%and 52.2%respectively in the disturbance.By contrast,when the external load was instantaneously connected,the corresponding values were 42.2%,31.3%and 64.3%respectively,indicating that the instantaneous external load connection had a greater disturbance impact on the FPEG operation stability.Despite encountering the step change of external load,the FPEG can still restore stable operation and show good anti-disturbance ability.Compared with increasing mixture flow rate,reducing the mixture flow rate has a greater disturbance impact on the engine operation stability.Although random misfire of a cylinder will cause remarkable fluctuations in piston displacement and cylinder pressure,the FPEG will not stop running,but continues to work as a single-piston engine.Minor collision event may adversely affect the stability of engine operation,but will not lead to the FPEG shutdown.However,serious collision event may lead to ignition failure and shutdown accident.
