This work deals with the development of a decentralized optimal control algorithm, along with a robust observer,for the relative motion control of spacecraft in leader-follower based formation. An adaptive gain higher...This work deals with the development of a decentralized optimal control algorithm, along with a robust observer,for the relative motion control of spacecraft in leader-follower based formation. An adaptive gain higher order sliding mode observer has been proposed to estimate the velocity as well as unmeasured disturbances from the noisy position measurements.A differentiator structure containing the Lipschitz constant and Lebesgue measurable control input, is utilized for obtaining the estimates. Adaptive tuning algorithms are derived based on Lyapunov stability theory, for updating the observer gains,which will give enough flexibility in the choice of initial estimates.Moreover, it may help to cope with unexpected state jerks. The trajectory tracking problem is formulated as a finite horizon optimal control problem, which is solved online. The control constraints are incorporated by using a nonquadratic performance functional. An adaptive update law has been derived for tuning the step size in the optimization algorithm, which may help to improve the convergence speed. Moreover, it is an attractive alternative to the heuristic choice of step size for diverse operating conditions. The disturbance as well as state estimates from the higher order sliding mode observer are utilized by the plant output prediction model, which will improve the overall performance of the controller. The nonlinear dynamics defined in leader fixed Euler-Hill frame has been considered for the present work and the reference trajectories are generated using Hill-Clohessy-Wiltshire equations of unperturbed motion. The simulation results based on rigorous perturbation analysis are presented to confirm the robustness of the proposed approach.展开更多
This paper proposes an adaptive sliding mode observer(ASMO)-based approach for wind turbines subject to simultaneous faults in sensors and actuators.The proposed approach enables the simultaneous detection of actuator...This paper proposes an adaptive sliding mode observer(ASMO)-based approach for wind turbines subject to simultaneous faults in sensors and actuators.The proposed approach enables the simultaneous detection of actuator and sensor faults without the need for any redundant hardware components.Additionally,wind speed variations are considered as unknown disturbances,thus eliminating the need for accurate measurement or estimation.The proposed ASMO enables the accurate estimation and reconstruction of the descriptor states and disturbances.The proposed design implements the principle of separation to enable the use of the nominal controller during faulty conditions.Fault tolerance is achieved by implementing a signal correction scheme to recover the nominal behavior.The performance of the proposed approach is validated using a 4.8 MW wind turbine benchmark model subject to various faults.Monte-Carlo analysis is also carried out to further evaluate the reliability and robustness of the proposed approach in the presence of measurement errors.Simplicity,ease of implementation and the decoupling property are among the positive features of the proposed approach.展开更多
This paper investigates the consensus problem of second-order nonlinear multi-agent systems (MASs) via the sliding mode control (SMC) approach. The velocity of each agent is assumed to be unmeasurable. A second-order ...This paper investigates the consensus problem of second-order nonlinear multi-agent systems (MASs) via the sliding mode control (SMC) approach. The velocity of each agent is assumed to be unmeasurable. A second-order sliding mode observer is designed to estimate the velocity. Then a distributed discontinuous control law based on first-order SMC is presented to solve the consensus problem. Moreover, to overcome the chatting problem, two controllers based on the boundary layer method and the super-twisting algorithm respectively are presented. It is shown that the MASs will achieve consensus under some given conditions. Some examples are provided to demonstrate the effectiveness of the proposed control laws.展开更多
To solve the chattering problem caused by discontinuous switching function in traditional sliding mode observer,a piecewise square root switching function with continuously varying characteristics is designed,and its ...To solve the chattering problem caused by discontinuous switching function in traditional sliding mode observer,a piecewise square root switching function with continuously varying characteristics is designed,and its stability is analyzed by using Lyapunov stability criterion.Secondly,according to the relationship among bus current,switching state and phase current,a single bus resistance sampling current reconstruction scheme without current sensors is adopted,which effectively reduces the cost of motor system.Finally,the feasibility and effectiveness of the proposed scheme are verified by simulation.展开更多
This paper presents a robust sixth-order Discrete-time Extended Sliding Mode Observer (DESMO) for sensorless control of PMSM in order to estimate the currents, speed, rotor position, load torque and stator resistance....This paper presents a robust sixth-order Discrete-time Extended Sliding Mode Observer (DESMO) for sensorless control of PMSM in order to estimate the currents, speed, rotor position, load torque and stator resistance. The satisfying simulation results on Simulink/Matlab environment for a 1.6 kW PMSM demonstrate the good performance and stability of the proposed ESMO algorithm against parameter variation, modeling uncertainty, measurement and system noises.展开更多
Fault detection of non-linear systems is of great importance in control systems reliability.Undetected faults could lead to irreparable damage.This paper deals with fault diagnosis of helicopter system in the presence...Fault detection of non-linear systems is of great importance in control systems reliability.Undetected faults could lead to irreparable damage.This paper deals with fault diagnosis of helicopter system in the presence of uncertainties and disturbances.To deal with sensor,actuator and component faults,the observer-based diagnosis scheme which employs sliding mode observer is designed.Faults are modelled as an additive and multiplicative fault which is introduced as an abrupt and intermittent fault into the system.Observer inequality constraints and gain matrices are solved using a Lyapunov-based approach.The results display the effectiveness of the designed observer and the ability to handle faults.展开更多
In this study,a six-phase induction asymmetric induction motor(SPAIM)was examined,whose performance surpasses that of its three-phase counterpart,with regard to the torque density,torque pulsation,fault tolerance,powe...In this study,a six-phase induction asymmetric induction motor(SPAIM)was examined,whose performance surpasses that of its three-phase counterpart,with regard to the torque density,torque pulsation,fault tolerance,power rating per inverter lag,and noise characteristics.Speed-encoder-less direct torque control(DTC)for SPAIM with virtual voltage vectors(VVVs)and a modified sliding mode observer(MSMO)are described.The SPAIM model was developed using a stationaryα-βframe for DTC.The conventional DTC of the SPAIM drive is a simple extension of DTC for a 3-Φmotor drive that yields higher distortion in the stator currents.To mitigate the large amount of distortion in the stator current,VVVs were used to significantly reduce the harmonic content in the stator currents.Furthermore,to overcome the large amount of chattering observed in the case of a traditional sliding mode observer,particularly under low-speed operation,the MSMO was employed to reduce chattering even under low-speed operation.The performance of the proposed observer was verified under all the operating conditions suitable for the propulsion mode of an electric vehicle using Matlab/Simulink,and the results were experimentally validated.展开更多
This paper proposes a design of control and estimation strategy for induction motor based on the variable structure approach.It describes a coupling of sliding mode direct torque control(DTC)with sliding mode flux and...This paper proposes a design of control and estimation strategy for induction motor based on the variable structure approach.It describes a coupling of sliding mode direct torque control(DTC)with sliding mode flux and speed observer.This algorithm uses direct torque control basics and the sliding mode approach.A robust electromagnetic torque and flux controllers are designed to overcome the conventional SVM-DTC draw・backs and to ensure fast response and full reference tracking with desired dynamic behavior and low ripple level.The sliding mode controller is used to generate reference voltages in stationary frame and give them to the controlled motor after modulation by a space vector modulation(SVM)inverter.The second aim of this paper is to design a sliding mode speed/flux observer which can improve the control performances by using a sensorless algorithm to get an accurate estimation,and consequently,increase the reliability of the system and decrease the cost of using sensors.The effectiveness of the whole composed control algorithm is investigated in different robustness tests with simulation using Matlab/Simulink and verified by real time experimental implementation based on dS pace 1104 board.展开更多
The fault-tolerant consensus problem for leader-following nonlinear multi-agent systems with actuator faults is mainly investigated.A new super-twisting sliding mode observer is constructed to estimate the velocity an...The fault-tolerant consensus problem for leader-following nonlinear multi-agent systems with actuator faults is mainly investigated.A new super-twisting sliding mode observer is constructed to estimate the velocity and undetectable fault information simultaneously.The time-varying gain is introduced to solve the initial error problem and peak value problem,which makes the observation more accurate and faster.Then,based on the estimated results,an improved sliding mode fault-tolerant consensus control algorithm is designed to compensate the actuator faults.The protocol can guarantee the finite-time consensus control of multi-agent systems and suppress chattering.Finally,the effectiveness and the superiority of the observer and control algorithm are proved by some simulation examples of the multi-aircraft system.展开更多
This paper considers the design of an adaptive second order terminal observer for robust fault reconstruction of nonlinear Lipschitz systems with unknown upper bound of derivative fault.Firstly,a linear transforming m...This paper considers the design of an adaptive second order terminal observer for robust fault reconstruction of nonlinear Lipschitz systems with unknown upper bound of derivative fault.Firstly,a linear transforming matrix is introduced,which transforms the system into two subsystems,and thus to reduce the dimension of the system.One of the subsystem is affected by fault and disturbances,while the other is free,which simplifies the design of observer.Then,the design method of the observer gain matrix is transformed into a convex optimization problem under linear matrix inequalities(LMIs).A second order non-singular terminal sliding mode observer is designed for the transformed system to realize the accurate estimation of state and fault.Considering the unknown upper bound of derivative fault,an adaptive algorithm is designed in the equivalent output error injection signal to ensure the sliding mode motion reach the sliding surface within limited time.Finally,an example demonstrates the effectiveness of the proposed method in the paper.展开更多
This paper describes an adaptive gain sliding mode observer for brushless DC motor for large variations in speed. Sensorless brushless DC motor based on sliding mode observer exhibits multiple zero crossing in back el...This paper describes an adaptive gain sliding mode observer for brushless DC motor for large variations in speed. Sensorless brushless DC motor based on sliding mode observer exhibits multiple zero crossing in back electromotive force (EMF) which leads to commutation problems at low speed. In this paper, a modified sliding mode observer incorporating a speed component in the estimation of back EMF is proposed. It is found that after incorporating the speed component in the back EMF observer gain, multiple zero crossings at low speeds and phase shift at higher speeds are eliminated. The trapezoidal back EMF observer is implemented experimentally on a digital signal processor (DSP) board. The effectiveness of the proposed method is demonstrated through simulations and experiments.展开更多
This paper presents a novel non-singular fast terminal sliding mode control(NFTSMC)based on the deep flux weakening switching point tracking method in order to improve the control performance of permanent interior mag...This paper presents a novel non-singular fast terminal sliding mode control(NFTSMC)based on the deep flux weakening switching point tracking method in order to improve the control performance of permanent interior magnet synchronous motor(IPMSM)drive systems.The mathematical model of flux weakening(FW)control is established,and the deep flux weakening switching point is calculated accurately by analyzing the relationship between the torque curve and voltage decline curve.Next,a second-order NFTSMC is designed for the speed loop controller to ensure that the system converges to the equilibrium state in finite time.Then,an extended sliding mode disturbance observer(ESMDO)is designed to estimate the uncertainty of the system.Finally,compared with both the PI control and sliding mode control(SMC)by simulations and experiments with different working conditions,the method proposed has the merits of accelerating convergence,improving steady-state accuracy,and minimizing the current and torque pulsation.展开更多
This paper investigates the design of an attitude autopilot for a dual-channel controlled spinning glideguided projectile(SGGP),addressing model uncertainties and external disturbances.Based on fixed-time stable theor...This paper investigates the design of an attitude autopilot for a dual-channel controlled spinning glideguided projectile(SGGP),addressing model uncertainties and external disturbances.Based on fixed-time stable theory,a disturbance observer with integral sliding mode and adaptive techniques is proposed to mitigate total disturbance effects,irrespective of initial conditions.By introducing an error integral signal,the dynamics of the SGGP are transformed into two separate second-order fully actuated systems.Subsequently,employing the high-order fully actuated approach and a parametric approach,the nonlinear dynamics of the SGGP are recast into a constant linear closed-loop system,ensuring that the projectile's attitude asymptotically tracks the given goal with the desired eigenstructure.Under the proposed composite control framework,the ultimately uniformly bounded stability of the closed-loop system is rigorously demonstrated via the Lyapunov method.Validation of the effectiveness of the proposed attitude autopilot design is provided through extensive numerical simulations.展开更多
This paper presents a novel model-free sliding mode control(MFSMC)method to improve the speed response of permanent magnet synchronous machine(PMSM)drive system.The ultra-local model(ULM)is first derived based on the ...This paper presents a novel model-free sliding mode control(MFSMC)method to improve the speed response of permanent magnet synchronous machine(PMSM)drive system.The ultra-local model(ULM)is first derived based on the input and the output of the PMSM.Then,the novel MFSMC method is presented,and the controller is designed based on ULM and MFSMC.A sliding mode observer(SMO)is constructed to estimate the unknown part of the ULM.The estimated unknown part is feedbacked to MFSMC controller to performcompensation for parameter perturbations and external disturbances.Compared with the sliding mode control(SMC)method,the results of simulation and experiment demonstrate that the presented MFSMC method improves the dynamic response and robustness of the PMSM drive system.展开更多
In this paper, a sliding mode control with adaptive gain combined with a high-order sliding mode observer to solve the tracking problem for a quadrotor UAV is addressed, in presence of bounded external disturbances an...In this paper, a sliding mode control with adaptive gain combined with a high-order sliding mode observer to solve the tracking problem for a quadrotor UAV is addressed, in presence of bounded external disturbances and parametric uncertainties. The high order sliding mode observer is designed for estimating the linear and angular speed in order to implement the proposed scheme. Furthermore, a Lyapunov function is introduced to design the controller with the adaptation law, whereas an analysis of finite time convergence towards to zero is provided, where sufficient conditions are obtained. Regarding previous works from literature, one important advantage of proposed strategy is that the gains of control are parameterized in terms of only one adaptive parameter, which reduces the control effort by avoiding gain overestimation. Numerical simulations for tracking control of the quadrotor are given to show the performance of proposed adaptive control–observer scheme.展开更多
Road friction coefficient real-time estimation methods is an important issue and problem in automotive active safety con- trol system development. First a fixed feedback gain sliding mode observer of road adhesion coe...Road friction coefficient real-time estimation methods is an important issue and problem in automotive active safety con- trol system development. First a fixed feedback gain sliding mode observer of road adhesion coefficient is designed through the es-tablishment of tire/road dynamic friction model in this article. The simulation results shows that the observer can well real-time iden-tify the current road adhesion characteristics. And more importantly, the observer only need wheel speed signal and the braking torque (brake pressure) signal, so the system is low cost, and its adaptability is good. There is no doubt this estimation method has a good application prospect.展开更多
For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type of interaction control.Specifically,in impedance control,...For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type of interaction control.Specifically,in impedance control,the dynamic relationship between the interaction force and the resulting motion is controlled.In order to control the impedance of a mechanical system,typically,the interaction force has to be sensed.Due to the inherent limitations of direct force sensing at the interaction site,in the present work,the interaction force is observed using robust observers.In particular,to enhance the accuracy of impedance control,a first order sliding mode impedance controller is designed and incorporated in the present paper.Its advantage over positionbased interaction control algorithms is demonstrated through experimentation.Experimental results are given to show the effectiveness of the proposed algorithms.展开更多
This article presents a complete nonlinear controller design for a class of spin-stabilized canard-controlled projectiles.Uniformly ultimate boundedness and tracking are achieved,exploiting a heavily coupled,bounded u...This article presents a complete nonlinear controller design for a class of spin-stabilized canard-controlled projectiles.Uniformly ultimate boundedness and tracking are achieved,exploiting a heavily coupled,bounded uncertain and highly nonlinear model of longitudinal and lateral dynamics.In order to estimate unmeasurable states,an observer is proposed for an augmented multiple-input-multiple-output(MIMO) nonlinear system with an adaptive sliding mode term against the disturbances.Under the frame of a backstepping design,an adaptive sliding mode output-feedback dynamic surface control(DSC) approach is derived recursively by virtue of the estimated states.The DSC technique is adopted to overcome the problem of ‘‘explosion of complexity" and relieve the stress of the guidance loop.It is proven that all signals of the MIMO closed-loop system,including the observer and controller,are uniformly ultimately bounded,and the tracking errors converge to an arbitrarily small neighborhood of the origin.Simulation results for the observer and controller are provided to illustrate the feasibility and effectiveness of the proposed approach.展开更多
In this paper,a sliding mode observer scheme of sensor fault diagnosis is proposed for a class of time delay nonlinear systems with input uncertainty based on neural network.The sensor fault and the system input uncer...In this paper,a sliding mode observer scheme of sensor fault diagnosis is proposed for a class of time delay nonlinear systems with input uncertainty based on neural network.The sensor fault and the system input uncertainty are assumed to be unknown but bounded.The radial basis function (RBF) neural network is used to approximate the sensor fault.Based on the output of the RBF neural network,the sliding mode observer is presented.Using the Lyapunov method,a criterion for stability is given in terms of matrix inequality.Finally,an example is given for illustrating the availability of the fault diagnosis based on the proposed sliding mode observer.展开更多
Purpose–The purpose of this paper is to investigate the stabilization of unstable periodic orbits of Chua’s system using adaptive fuzzy sliding mode controllers with moving surface.Design/methodology/approach–For t...Purpose–The purpose of this paper is to investigate the stabilization of unstable periodic orbits of Chua’s system using adaptive fuzzy sliding mode controllers with moving surface.Design/methodology/approach–For this aim,the sliding mode controller and fuzzy systems are combined to achieve the stabilization.Then,the authors propose a moving sliding surface to improve robustness against uncertainties during the reaching phase,parameter variations and extraneous disturbances.Findings–Afterward,the authors design a sliding observer to estimate the unmeasurable states which are used in the previously designed controller.Originality/value–Numerical results are provided to show the effectiveness and robustness of the proposed method.展开更多
文摘This work deals with the development of a decentralized optimal control algorithm, along with a robust observer,for the relative motion control of spacecraft in leader-follower based formation. An adaptive gain higher order sliding mode observer has been proposed to estimate the velocity as well as unmeasured disturbances from the noisy position measurements.A differentiator structure containing the Lipschitz constant and Lebesgue measurable control input, is utilized for obtaining the estimates. Adaptive tuning algorithms are derived based on Lyapunov stability theory, for updating the observer gains,which will give enough flexibility in the choice of initial estimates.Moreover, it may help to cope with unexpected state jerks. The trajectory tracking problem is formulated as a finite horizon optimal control problem, which is solved online. The control constraints are incorporated by using a nonquadratic performance functional. An adaptive update law has been derived for tuning the step size in the optimization algorithm, which may help to improve the convergence speed. Moreover, it is an attractive alternative to the heuristic choice of step size for diverse operating conditions. The disturbance as well as state estimates from the higher order sliding mode observer are utilized by the plant output prediction model, which will improve the overall performance of the controller. The nonlinear dynamics defined in leader fixed Euler-Hill frame has been considered for the present work and the reference trajectories are generated using Hill-Clohessy-Wiltshire equations of unperturbed motion. The simulation results based on rigorous perturbation analysis are presented to confirm the robustness of the proposed approach.
文摘This paper proposes an adaptive sliding mode observer(ASMO)-based approach for wind turbines subject to simultaneous faults in sensors and actuators.The proposed approach enables the simultaneous detection of actuator and sensor faults without the need for any redundant hardware components.Additionally,wind speed variations are considered as unknown disturbances,thus eliminating the need for accurate measurement or estimation.The proposed ASMO enables the accurate estimation and reconstruction of the descriptor states and disturbances.The proposed design implements the principle of separation to enable the use of the nominal controller during faulty conditions.Fault tolerance is achieved by implementing a signal correction scheme to recover the nominal behavior.The performance of the proposed approach is validated using a 4.8 MW wind turbine benchmark model subject to various faults.Monte-Carlo analysis is also carried out to further evaluate the reliability and robustness of the proposed approach in the presence of measurement errors.Simplicity,ease of implementation and the decoupling property are among the positive features of the proposed approach.
基金supported by the National Natural Science Foundation of China(6137510561403334)
文摘This paper investigates the consensus problem of second-order nonlinear multi-agent systems (MASs) via the sliding mode control (SMC) approach. The velocity of each agent is assumed to be unmeasurable. A second-order sliding mode observer is designed to estimate the velocity. Then a distributed discontinuous control law based on first-order SMC is presented to solve the consensus problem. Moreover, to overcome the chatting problem, two controllers based on the boundary layer method and the super-twisting algorithm respectively are presented. It is shown that the MASs will achieve consensus under some given conditions. Some examples are provided to demonstrate the effectiveness of the proposed control laws.
文摘To solve the chattering problem caused by discontinuous switching function in traditional sliding mode observer,a piecewise square root switching function with continuously varying characteristics is designed,and its stability is analyzed by using Lyapunov stability criterion.Secondly,according to the relationship among bus current,switching state and phase current,a single bus resistance sampling current reconstruction scheme without current sensors is adopted,which effectively reduces the cost of motor system.Finally,the feasibility and effectiveness of the proposed scheme are verified by simulation.
文摘This paper presents a robust sixth-order Discrete-time Extended Sliding Mode Observer (DESMO) for sensorless control of PMSM in order to estimate the currents, speed, rotor position, load torque and stator resistance. The satisfying simulation results on Simulink/Matlab environment for a 1.6 kW PMSM demonstrate the good performance and stability of the proposed ESMO algorithm against parameter variation, modeling uncertainty, measurement and system noises.
文摘Fault detection of non-linear systems is of great importance in control systems reliability.Undetected faults could lead to irreparable damage.This paper deals with fault diagnosis of helicopter system in the presence of uncertainties and disturbances.To deal with sensor,actuator and component faults,the observer-based diagnosis scheme which employs sliding mode observer is designed.Faults are modelled as an additive and multiplicative fault which is introduced as an abrupt and intermittent fault into the system.Observer inequality constraints and gain matrices are solved using a Lyapunov-based approach.The results display the effectiveness of the designed observer and the ability to handle faults.
文摘In this study,a six-phase induction asymmetric induction motor(SPAIM)was examined,whose performance surpasses that of its three-phase counterpart,with regard to the torque density,torque pulsation,fault tolerance,power rating per inverter lag,and noise characteristics.Speed-encoder-less direct torque control(DTC)for SPAIM with virtual voltage vectors(VVVs)and a modified sliding mode observer(MSMO)are described.The SPAIM model was developed using a stationaryα-βframe for DTC.The conventional DTC of the SPAIM drive is a simple extension of DTC for a 3-Φmotor drive that yields higher distortion in the stator currents.To mitigate the large amount of distortion in the stator current,VVVs were used to significantly reduce the harmonic content in the stator currents.Furthermore,to overcome the large amount of chattering observed in the case of a traditional sliding mode observer,particularly under low-speed operation,the MSMO was employed to reduce chattering even under low-speed operation.The performance of the proposed observer was verified under all the operating conditions suitable for the propulsion mode of an electric vehicle using Matlab/Simulink,and the results were experimentally validated.
文摘This paper proposes a design of control and estimation strategy for induction motor based on the variable structure approach.It describes a coupling of sliding mode direct torque control(DTC)with sliding mode flux and speed observer.This algorithm uses direct torque control basics and the sliding mode approach.A robust electromagnetic torque and flux controllers are designed to overcome the conventional SVM-DTC draw・backs and to ensure fast response and full reference tracking with desired dynamic behavior and low ripple level.The sliding mode controller is used to generate reference voltages in stationary frame and give them to the controlled motor after modulation by a space vector modulation(SVM)inverter.The second aim of this paper is to design a sliding mode speed/flux observer which can improve the control performances by using a sensorless algorithm to get an accurate estimation,and consequently,increase the reliability of the system and decrease the cost of using sensors.The effectiveness of the whole composed control algorithm is investigated in different robustness tests with simulation using Matlab/Simulink and verified by real time experimental implementation based on dS pace 1104 board.
基金supported by Key Laboratories for National Defense Science and Technology(6142605200402)the Aeronautical Science Foundation of China(20200007018001)+2 种基金the National Natural Science Foundation of China(61922042)the Aero Engine Corporation of China Industry-University-Research Cooperation Project(HFZL2020CXY011)the Research Fund of State Key Laboratory of Mechanics and Control of Mechanical Structures(Nanjing University of Aeron autics and astronautics)(MCMS-I-0121G03)。
文摘The fault-tolerant consensus problem for leader-following nonlinear multi-agent systems with actuator faults is mainly investigated.A new super-twisting sliding mode observer is constructed to estimate the velocity and undetectable fault information simultaneously.The time-varying gain is introduced to solve the initial error problem and peak value problem,which makes the observation more accurate and faster.Then,based on the estimated results,an improved sliding mode fault-tolerant consensus control algorithm is designed to compensate the actuator faults.The protocol can guarantee the finite-time consensus control of multi-agent systems and suppress chattering.Finally,the effectiveness and the superiority of the observer and control algorithm are proved by some simulation examples of the multi-aircraft system.
基金the National Natural Science Foundation of China(No.61304120)。
文摘This paper considers the design of an adaptive second order terminal observer for robust fault reconstruction of nonlinear Lipschitz systems with unknown upper bound of derivative fault.Firstly,a linear transforming matrix is introduced,which transforms the system into two subsystems,and thus to reduce the dimension of the system.One of the subsystem is affected by fault and disturbances,while the other is free,which simplifies the design of observer.Then,the design method of the observer gain matrix is transformed into a convex optimization problem under linear matrix inequalities(LMIs).A second order non-singular terminal sliding mode observer is designed for the transformed system to realize the accurate estimation of state and fault.Considering the unknown upper bound of derivative fault,an adaptive algorithm is designed in the equivalent output error injection signal to ensure the sliding mode motion reach the sliding surface within limited time.Finally,an example demonstrates the effectiveness of the proposed method in the paper.
文摘This paper describes an adaptive gain sliding mode observer for brushless DC motor for large variations in speed. Sensorless brushless DC motor based on sliding mode observer exhibits multiple zero crossing in back electromotive force (EMF) which leads to commutation problems at low speed. In this paper, a modified sliding mode observer incorporating a speed component in the estimation of back EMF is proposed. It is found that after incorporating the speed component in the back EMF observer gain, multiple zero crossings at low speeds and phase shift at higher speeds are eliminated. The trapezoidal back EMF observer is implemented experimentally on a digital signal processor (DSP) board. The effectiveness of the proposed method is demonstrated through simulations and experiments.
基金supported by the Natural Science Foundation of China under Grant No.61733004the Scientific Research Fund of the Hunan Provincial Education Department under Grand No.18A267.
文摘This paper presents a novel non-singular fast terminal sliding mode control(NFTSMC)based on the deep flux weakening switching point tracking method in order to improve the control performance of permanent interior magnet synchronous motor(IPMSM)drive systems.The mathematical model of flux weakening(FW)control is established,and the deep flux weakening switching point is calculated accurately by analyzing the relationship between the torque curve and voltage decline curve.Next,a second-order NFTSMC is designed for the speed loop controller to ensure that the system converges to the equilibrium state in finite time.Then,an extended sliding mode disturbance observer(ESMDO)is designed to estimate the uncertainty of the system.Finally,compared with both the PI control and sliding mode control(SMC)by simulations and experiments with different working conditions,the method proposed has the merits of accelerating convergence,improving steady-state accuracy,and minimizing the current and torque pulsation.
基金supported by the National Natural Science Foundation of China(Grant Nos.52272358 and 62103052)。
文摘This paper investigates the design of an attitude autopilot for a dual-channel controlled spinning glideguided projectile(SGGP),addressing model uncertainties and external disturbances.Based on fixed-time stable theory,a disturbance observer with integral sliding mode and adaptive techniques is proposed to mitigate total disturbance effects,irrespective of initial conditions.By introducing an error integral signal,the dynamics of the SGGP are transformed into two separate second-order fully actuated systems.Subsequently,employing the high-order fully actuated approach and a parametric approach,the nonlinear dynamics of the SGGP are recast into a constant linear closed-loop system,ensuring that the projectile's attitude asymptotically tracks the given goal with the desired eigenstructure.Under the proposed composite control framework,the ultimately uniformly bounded stability of the closed-loop system is rigorously demonstrated via the Lyapunov method.Validation of the effectiveness of the proposed attitude autopilot design is provided through extensive numerical simulations.
基金This work was supported in part by the Hunan Provincial Natural Science Foundation of China under Grant Nos.2020JJ6083,2019JJ40072,2021JJ50052 and 2020JJ6067the Program of JSPS(Japan Society for the Promotion of Science)International Research Fellows under Grant No.19F19703+3 种基金the Scientific Research Fund of the Hunan Provincial Education Department under Grant No.18A267the Natural Science Foundation of China under Grant No.61773159in part by the Teaching Reform Research Project of Hunan Provincial Education Department of China(Hunan Education Notice[2019]No.291)under Grant No.543the Degree&Postgraduate Education Reform Project of Hunan Province under Grant No.2019JGZD068.
文摘This paper presents a novel model-free sliding mode control(MFSMC)method to improve the speed response of permanent magnet synchronous machine(PMSM)drive system.The ultra-local model(ULM)is first derived based on the input and the output of the PMSM.Then,the novel MFSMC method is presented,and the controller is designed based on ULM and MFSMC.A sliding mode observer(SMO)is constructed to estimate the unknown part of the ULM.The estimated unknown part is feedbacked to MFSMC controller to performcompensation for parameter perturbations and external disturbances.Compared with the sliding mode control(SMC)method,the results of simulation and experiment demonstrate that the presented MFSMC method improves the dynamic response and robustness of the PMSM drive system.
文摘In this paper, a sliding mode control with adaptive gain combined with a high-order sliding mode observer to solve the tracking problem for a quadrotor UAV is addressed, in presence of bounded external disturbances and parametric uncertainties. The high order sliding mode observer is designed for estimating the linear and angular speed in order to implement the proposed scheme. Furthermore, a Lyapunov function is introduced to design the controller with the adaptation law, whereas an analysis of finite time convergence towards to zero is provided, where sufficient conditions are obtained. Regarding previous works from literature, one important advantage of proposed strategy is that the gains of control are parameterized in terms of only one adaptive parameter, which reduces the control effort by avoiding gain overestimation. Numerical simulations for tracking control of the quadrotor are given to show the performance of proposed adaptive control–observer scheme.
基金Partially Supported by Henan Polytechnic University Doctoral Fund(No.B2010-12)+2 种基金Natural Science Fund of Henan Province Education Department(No.2011B580001)Henan Province Key Technology Research Project(No.122102210045)
文摘Road friction coefficient real-time estimation methods is an important issue and problem in automotive active safety con- trol system development. First a fixed feedback gain sliding mode observer of road adhesion coefficient is designed through the es-tablishment of tire/road dynamic friction model in this article. The simulation results shows that the observer can well real-time iden-tify the current road adhesion characteristics. And more importantly, the observer only need wheel speed signal and the braking torque (brake pressure) signal, so the system is low cost, and its adaptability is good. There is no doubt this estimation method has a good application prospect.
文摘For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type of interaction control.Specifically,in impedance control,the dynamic relationship between the interaction force and the resulting motion is controlled.In order to control the impedance of a mechanical system,typically,the interaction force has to be sensed.Due to the inherent limitations of direct force sensing at the interaction site,in the present work,the interaction force is observed using robust observers.In particular,to enhance the accuracy of impedance control,a first order sliding mode impedance controller is designed and incorporated in the present paper.Its advantage over positionbased interaction control algorithms is demonstrated through experimentation.Experimental results are given to show the effectiveness of the proposed algorithms.
基金supported by the National Natural Science Foundation of China(No.11532002)
文摘This article presents a complete nonlinear controller design for a class of spin-stabilized canard-controlled projectiles.Uniformly ultimate boundedness and tracking are achieved,exploiting a heavily coupled,bounded uncertain and highly nonlinear model of longitudinal and lateral dynamics.In order to estimate unmeasurable states,an observer is proposed for an augmented multiple-input-multiple-output(MIMO) nonlinear system with an adaptive sliding mode term against the disturbances.Under the frame of a backstepping design,an adaptive sliding mode output-feedback dynamic surface control(DSC) approach is derived recursively by virtue of the estimated states.The DSC technique is adopted to overcome the problem of ‘‘explosion of complexity" and relieve the stress of the guidance loop.It is proven that all signals of the MIMO closed-loop system,including the observer and controller,are uniformly ultimately bounded,and the tracking errors converge to an arbitrarily small neighborhood of the origin.Simulation results for the observer and controller are provided to illustrate the feasibility and effectiveness of the proposed approach.
基金Natural Science Foundation of Jiangsu Province (No.SBK20082815)Aeronautical Science Foundation of China (No.20075152014)
文摘In this paper,a sliding mode observer scheme of sensor fault diagnosis is proposed for a class of time delay nonlinear systems with input uncertainty based on neural network.The sensor fault and the system input uncertainty are assumed to be unknown but bounded.The radial basis function (RBF) neural network is used to approximate the sensor fault.Based on the output of the RBF neural network,the sliding mode observer is presented.Using the Lyapunov method,a criterion for stability is given in terms of matrix inequality.Finally,an example is given for illustrating the availability of the fault diagnosis based on the proposed sliding mode observer.
文摘Purpose–The purpose of this paper is to investigate the stabilization of unstable periodic orbits of Chua’s system using adaptive fuzzy sliding mode controllers with moving surface.Design/methodology/approach–For this aim,the sliding mode controller and fuzzy systems are combined to achieve the stabilization.Then,the authors propose a moving sliding surface to improve robustness against uncertainties during the reaching phase,parameter variations and extraneous disturbances.Findings–Afterward,the authors design a sliding observer to estimate the unmeasurable states which are used in the previously designed controller.Originality/value–Numerical results are provided to show the effectiveness and robustness of the proposed method.