In this paper, switched controllers are designed for a class of nonlinear discrete singular systems and a class of discrete singular bilinear systems. An invariant principle is presented for such switched nonlinear si...In this paper, switched controllers are designed for a class of nonlinear discrete singular systems and a class of discrete singular bilinear systems. An invariant principle is presented for such switched nonlinear singular systems. The invariant principle and the switched controllers are used to globally stabilize a class of singular bilinear systems that are not open-loop stable.展开更多
A modeling framework has been constructed using the theory of hybrid control systems for the switched control systems (SCS) and it can be more effectively used to describe the behavior of the systems and to more easil...A modeling framework has been constructed using the theory of hybrid control systems for the switched control systems (SCS) and it can be more effectively used to describe the behavior of the systems and to more easily realize the simulation of the closed loop SCS under the MATLAB environment. On the other hand, a hybrid automaton model is established to analyze and verify the switched control systems. The proposed method is illustrated by an example of switched inverted pendulum control system.展开更多
Recently, switched control systems have been attracting much attention m the control community because the problems are not only academically challenging for the inherent complexity, but also of practical importance d...Recently, switched control systems have been attracting much attention m the control community because the problems are not only academically challenging for the inherent complexity, but also of practical importance due to its wide ranges of applications in nature, engineering, and social sciences.展开更多
As vip editors, it is our great honor to bring this special issue of the Journal of Control Theory and Applications devoted to Recent Advances and New Directions in Switched Control Systems.
Switched linear parameter varying(LPV)systems have,in recent years,inspired a great number of research endeavors owing to their excellent ability to approximate nonlinear systems and handle complex hybrid dynamics in ...Switched linear parameter varying(LPV)systems have,in recent years,inspired a great number of research endeavors owing to their excellent ability to approximate nonlinear systems and handle complex hybrid dynamics in system analysis and synthesis.Nevertheless,numerous difficulties and challenges are also encountered due to the reciprocal effects of switching signals and scheduling parameters in the analysis and synthesis of switched LPV systems.In this paper,the standard description and specific characteristics of switched LPV systems are first introduced.Then,the main methodologies are proposed in the literature to cope with stability and performance analysis,control synthesis,as well as fault diagnosis and fault-tolerant control issues,and the typical applications in various fields are surveyed.Finally,several key open problems and current research activities are also discussed to elucidate the potential research directions in the future.展开更多
This paper proposes a high-speed nonsingular terminal switched sliding mode control(HNT-SSMC) strategy for robot manipulators. The proposed approach enhances the control system performance by switching among appropria...This paper proposes a high-speed nonsingular terminal switched sliding mode control(HNT-SSMC) strategy for robot manipulators. The proposed approach enhances the control system performance by switching among appropriate sliding mode controllers according to different control demands in different regions of the state space. It is shown that the highspeed nonsingular terminal switched sliding mode(HNT-SSM)which is the representation of different control demands and enforced by the HNT-SSMC has the property of global highspeed convergence compared with the nonsingular fast terminal sliding mode(NFTSM), and provides the global non-singularity.The simulation study of an application example is carried out to validate the effectiveness of the proposed strategy.展开更多
This paper presents an entire fixed-time disturbance observer-based global terminal switching sliding mode control of robot manipulators,which has inner and external uncertainties.The entire fixed-time disturbance obs...This paper presents an entire fixed-time disturbance observer-based global terminal switching sliding mode control of robot manipulators,which has inner and external uncertainties.The entire fixed-time disturbance observer-based global terminal switching sliding mode control has the global finite-time reaching characteristic,the property that system convergence time can be prescribed,and the global robustness to uncertainties,with the entire fixed-time disturbance observer that accurately estimates uncertainties after a fixed time,despite the initial state.The joints of the control system can arrive at the prescribed joint angular position at the predefined joint angular speed at the prescribed time.展开更多
This paper deals with the problem of non-fragile linear parameter-varying（LPV） H_∞ control for morphing aircraft with asynchronous switching.The switched LPV model of morphing aircraft is established by Jacobian li...This paper deals with the problem of non-fragile linear parameter-varying（LPV） H_∞ control for morphing aircraft with asynchronous switching.The switched LPV model of morphing aircraft is established by Jacobian linearization approach according to the nonlinear model.The data missing is taken into account in the link from sensors to controllers and the link from controllers to actuators,which satisfies Bernoulli distribution.The non-fragile switched LPV controllers are constructed with consideration of the uncertainties of controllers and asynchronous switching phenomenon.The parameter-dependent Lyapunov functional method and mode-dependent average dwell time（MDADT） method are combined to guarantee the stability and prescribed performance of the system.The sufficient conditions on the solvability of the problem are derived in the form of linear matrix inequalities（LMI）.In order to achieve higher efficiency of the designing process,an algorithm is applied to divide the whole set into subsets automatically.Simulation results are provided to verify the effectiveness and superiority of the method in the paper.展开更多
In this paper, we proposed an output voltage stabilization of a DC-DC Zeta converter using hybrid control. We modeled the Zeta converter under continuous conduction mode operation. We derived a switching control law t...In this paper, we proposed an output voltage stabilization of a DC-DC Zeta converter using hybrid control. We modeled the Zeta converter under continuous conduction mode operation. We derived a switching control law that brings the output voltage to the desired level. Due to infinite switching occurring at the desired level, we enhanced the switching control law by allowing a sizeable output voltage ripple. We derived mathematical models that allow one to choose the desired switching frequency. In practice, the existence of the non-ideal properties of the Zeta converter results in steady-state output voltage error. By analyzing the power loss in the zeta converter, we proposed an improved switching control law that eliminates the steady-state output voltage error. The effectiveness of the proposed method is illustrated with simulation results.展开更多
In order to design a suitable controller which can achieve accurate trajectory tracking and a good control performance, and guarantee the stability and robustness of a robot system due to external disturbances error a...In order to design a suitable controller which can achieve accurate trajectory tracking and a good control performance, and guarantee the stability and robustness of a robot system due to external disturbances error and internal parameter variations, an adaptive switching control strategy is proposed. The proposed scheme is designed under the condition of bounded distances and consists of an adaptive switching law and a PD controller. Based on the Lyapunov stability theory, it is proved that the proposed scheme can guarantee the tracking performance of the robotic manipulator and is adapted to varying unknown loads. Simulations are carded out on a two-link robotic manipulator, which illustrate the feasibility and validity of the proposed control scheme and the robustness for variational payloads.展开更多
This paper proposes a switching multi-objective model predictive control(MOMPC) algorithm for constrained nonlinear continuous-time process systems.Different cost functions to be minimized in MPC are switched to satis...This paper proposes a switching multi-objective model predictive control(MOMPC) algorithm for constrained nonlinear continuous-time process systems.Different cost functions to be minimized in MPC are switched to satisfy different performance criteria imposed at different sampling times.In order to ensure recursive feasibility of the switching MOMPC and stability of the resulted closed-loop system,the dual-mode control method is used to design the switching MOMPC controller.In this method,a local control law with some free-parameters is constructed using the control Lyapunov function technique to enlarge the terminal state set of MOMPC.The correction term is computed if the states are out of the terminal set and the free-parameters of the local control law are computed if the states are in the terminal set.The recursive feasibility of the MOMPC and stability of the resulted closed-loop system are established in the presence of constraints and arbitrary switches between cost functions.Finally,implementation of the switching MOMPC controller is demonstrated with a chemical process example for the continuous stirred tank reactor.展开更多
The primary sensor of astronomy observation satellite （AOS） is mounted on a gimbal base which connects directly with the satellite platform and has two degrees of freedom. Attitude control for AOS with a swinging se...The primary sensor of astronomy observation satellite （AOS） is mounted on a gimbal base which connects directly with the satellite platform and has two degrees of freedom. Attitude control for AOS with a swinging sensor will be highlighted in this paper. Due to the non-negligible mass and length of the sensor, the internal motion between the satellite and the sensor will change the attitude, the position of center of mass and moment of inertia of the SYSTEM （consists of the satellite and the sen- sor）. According to moment of momentum theorem, a rigid two-body dynamic model is derived, which can he used to determine the inertial tensor of the SYSTEM. Modulating the satellite＇s present and desired quaternions results in quasi-Euler angles and normalizing these resultant parameters can ensure that the channel corresponding to each quasi-Euler angle is in the charge of each component of the control torque. Based on the normalized quasi-Euler angles, a switching attitude control law is proposed. With the control law, the corresponding phase trajectory will slide along the switching surface to the origin （corresponding to the desired states）. Simulation results show that the satellite can be controlled perfectly by thrusters with the proposed control law, even in the case of structural asymmetry and serious coupling between the control channels.展开更多
A novel gain-scheduled switching control method for the longitudinal motion of a flexible air-breathing hypersonic vehicle （FAHV） is proposed. Firstly, velocity and altitude are selected as scheduling variables, a p...A novel gain-scheduled switching control method for the longitudinal motion of a flexible air-breathing hypersonic vehicle （FAHV） is proposed. Firstly, velocity and altitude are selected as scheduling variables, a polytopic linear parameter varying （LPV） model is developed to represent the complex nonlinear longitudinal dynamics of the FAHV. Secondly, based on the obtained polytopic LPV model, the flight envelope is divided into four smaller subregions, and four gain-scheduled controllers are designed for these parameter subregions. Then, by the defined switching characteristic function, these gain-scheduled controllers are switched in order to guarantee the closed-loop FAHV system to be asymptotically stable and satisfy a given tracking error performance criterion. The condition of gain-scheduled switching controller synthesis is given in terms of linear matrix inequalities （LMIs） which can be easily solved by using standard software packages. Finally, simulation results show the effectiveness of the presented method.展开更多
With the increasing number of human-robot interaction applications, robot control characteristics and their effects on safety as well as performance should be taken account into the robot control system. In this paper...With the increasing number of human-robot interaction applications, robot control characteristics and their effects on safety as well as performance should be taken account into the robot control system. In this paper, a position and torque switching con- trol method was proposed to improve the robot safety and performance, when robots and humans work in the same space. The switch- ing control method includes two modes, the position control mode using a proportion-integral （PI） algorithm, and the torque control mode using sliding mode control （SMC） algorithm for eliminating swing. Under the normal condition, the robot works in position con- trol mode for trajectory tracking with quick response. Once the robot and human collide, the robot will switch to torque control mode immediately, and the impact force will be restricted within a safe range. When the robot and human detach, the robot will resume to po- sition control mode automatically. Moreover, for a better performance, the joint torque is detected fl＇om direct-current （DC） motor＇s cur- rent rather than the torque sensor. The experiment results show that the proposed approach is effective and feasible.展开更多
Efficient walking is one of the main goals of researches on biped robots. A feasible way is to translate the understanding from human walking into robot walking, for example, an artificial control approach on a human ...Efficient walking is one of the main goals of researches on biped robots. A feasible way is to translate the understanding from human walking into robot walking, for example, an artificial control approach on a human like walking structure. In this paper, a walking pattern based on Center of Pressure （COP） switched and modeled after human walking is introduced firstly. Then, a parameterization method for the proposed walking gait is presented. In view of the complication, a multi-space planning method which divides the whole planning task into three sub-spaces, including simplified model space, work space and joint space, is proposed. Furthermore, a finite-state-based control method is also developed to implement the proposed walking pattern. The state switches of this method are driven by sensor events. For convincing verification, a 2D simulation system with a 9-1ink planar biped robot is developed. The simulation results exhibit an efficient walking gait.展开更多
This paper deals with the problem of switching between an open-loop estimator and a close-loop estimator for compensating transmission error and packet dropout of networked control systems. Switching impulse is consid...This paper deals with the problem of switching between an open-loop estimator and a close-loop estimator for compensating transmission error and packet dropout of networked control systems. Switching impulse is considered in order to reduce the error between theory and application, a sufficient condition for exponential stabilization of networked control systems under a given switching rule is presented by multiple Lyapunov-like functions. These results are presented for both continuous-time and discrete-time domains. Controllers are designed by means of linear matrix inequalities. Sim- ulation results show the feasibility and efficiency of the proposed method.展开更多
In hydraulic area,independent metering control(IMC)technology is an effective approach to improve system efficiency and control flexibility.In addition,digital hydraulic technology(DHT)has been verified as a reasonabl...In hydraulic area,independent metering control(IMC)technology is an effective approach to improve system efficiency and control flexibility.In addition,digital hydraulic technology(DHT)has been verified as a reasonable method to optimize system dynamic performance.Integrating these two technologies into one component can combine their advantages together.However,few works focused on it.In this paper,a twin spools valve with switching technologycontrolled pilot stage(TSVSP)is presented,which applied DHT into its pilot stage while appending IMC into its main stage.Based on this prototype valve,a series of numerical and experiment analysis of its IMC performance with both simulated load and excavator boom cylinder are carried out.Results showed fast and robust performance of pressure and flow compound control with acceptable fluctuation phenomenon caused by switching technology.Rising time of flow response in excavator cylinder can be controlled within 200 ms,meanwhile,the recovery time of rod chamber pressure under suddenly changed condition is optimized within 250 ms.IMC system based on TSVSP can improve both dynamic performance and robust characteristics of the target actuator so it is practical in valve-cylinder system and can be applied in mobile machineries.展开更多
In order to realize the fault diagnosis of the control circuit of all-electronic computer interlocking system(ACIS)for railway signals,taking a five-wire switch electronic control module as an research object,we propo...In order to realize the fault diagnosis of the control circuit of all-electronic computer interlocking system(ACIS)for railway signals,taking a five-wire switch electronic control module as an research object,we propose a method of selecting the sample set of the basic classifier by roulette method and realizing fault diagnosis by using SVM-AdaBoost.The experimental results show that the proportion of basic classifier samples affects classification accuracy,which reaches the highest when the proportion is 85%.When selecting the sample set of basic classifier by roulette method,the fault diagnosis accuracy is generally higher than that of the maximum weight priority method.When the optimal proportion 85%is taken,the accuracy is highest up to 96.3%.More importantly,this way can better adapt to the critical data and improve the anti-interference ability of the algorithm,and therefore it provides a basis for fault diagnosis of ACIS.展开更多
This article proposes a linear parameter varying （LPV） switching tracking control scheme for a flexible air-breathing hypersonic vehicle （FAHV）. First, a polytopic LPV model is constructed to represent the complex...This article proposes a linear parameter varying （LPV） switching tracking control scheme for a flexible air-breathing hypersonic vehicle （FAHV）. First, a polytopic LPV model is constructed to represent the complex nonlinear longitudinal model of the FAHV by using Jacobian linearization and tensor-product （T-P） model transformation approach. Second, for less conservative controller design purpose, the flight envelope is divided into four sub-regions and a non-fragile LPV controller is designed for each parameter sub-region. These non-fragile LPV controllers are then switched in order to guarantee the closed-loop FAHV system to be asymptotically stable and satisfy a specified performance criterion. The desired non-fragile LPV switching controller is found by solving a convex constraint problem which can be efficiently solved using available linear matrix inequality （LMI） techniques, and robust stability analysis of the closed-loop FAHV system is verified based on multiple Lypapunov functions （MLFs）. Finally, numerical simulations have demonstrated the effectiveness of the proposed approach.展开更多
A tilt-rotor aircraft has three flight modes: helicopter mode, airplane mode and conversion mode. Unlike the traditional aircraft, the tilt-rotor aircraft, which combines the characteristics of helicopters and fixed-w...A tilt-rotor aircraft has three flight modes: helicopter mode, airplane mode and conversion mode. Unlike the traditional aircraft, the tilt-rotor aircraft, which combines the characteristics of helicopters and fixed-wing aircraft, is a complex multi-body system with the violent variation of the aerodynamic parameters. For these characteristics, a new smooth switching control scheme is provided for the tilt-rotor aircraft. First, the reference commands for airspeed and nacelle angles are calculated by analyzing the conversion corridor and the conversion path. Subsequently, based on the finite-time switching theorem, an average dwell time condition is designed to guarantee the stability in the switching process. Besides, considering the state vibrations and bumps may appear in switching points, the fuzzy weighted logic is employed to improve the system transient performance. For disturbance rejection, three extended state observers are designed separately to estimate the disturbances in the switched systems. Compared with the traditional auto disturbance rejection control and proportion integration differentiation control, this method overcomes the conservatism of wasting the whole model information. The control performances of robustness and smoothness are verified with simulation, which shows that the new smooth switching control scheme is more targeted and superior than the traditional design method.展开更多
基金This work was supported by the Science Technical Foundation of Liaoning of China (No. 2001401041)
文摘In this paper, switched controllers are designed for a class of nonlinear discrete singular systems and a class of discrete singular bilinear systems. An invariant principle is presented for such switched nonlinear singular systems. The invariant principle and the switched controllers are used to globally stabilize a class of singular bilinear systems that are not open-loop stable.
文摘A modeling framework has been constructed using the theory of hybrid control systems for the switched control systems (SCS) and it can be more effectively used to describe the behavior of the systems and to more easily realize the simulation of the closed loop SCS under the MATLAB environment. On the other hand, a hybrid automaton model is established to analyze and verify the switched control systems. The proposed method is illustrated by an example of switched inverted pendulum control system.
文摘Recently, switched control systems have been attracting much attention m the control community because the problems are not only academically challenging for the inherent complexity, but also of practical importance due to its wide ranges of applications in nature, engineering, and social sciences.
文摘As vip editors, it is our great honor to bring this special issue of the Journal of Control Theory and Applications devoted to Recent Advances and New Directions in Switched Control Systems.
基金supported in part by the National Natural Science Foundation of China(62222310,61973131,62473379)the National Key Research and Develepment Program of China(2024YFB3310701)+1 种基金the Research Fund for the Taishan Scholar Project of Shandong Province of China,the Major Basic Research of Natural Science Foundation of Shandong Province(ZR2024ZD38,ZR2022ZD34)the Japan Society for the Promotion of Science(21K04129).
文摘Switched linear parameter varying(LPV)systems have,in recent years,inspired a great number of research endeavors owing to their excellent ability to approximate nonlinear systems and handle complex hybrid dynamics in system analysis and synthesis.Nevertheless,numerous difficulties and challenges are also encountered due to the reciprocal effects of switching signals and scheduling parameters in the analysis and synthesis of switched LPV systems.In this paper,the standard description and specific characteristics of switched LPV systems are first introduced.Then,the main methodologies are proposed in the literature to cope with stability and performance analysis,control synthesis,as well as fault diagnosis and fault-tolerant control issues,and the typical applications in various fields are surveyed.Finally,several key open problems and current research activities are also discussed to elucidate the potential research directions in the future.
基金supported partially by the Research Program of Science and Technology at Universities of Inner Mongolia Autonomous Region(NJZY13279)
文摘This paper proposes a high-speed nonsingular terminal switched sliding mode control(HNT-SSMC) strategy for robot manipulators. The proposed approach enhances the control system performance by switching among appropriate sliding mode controllers according to different control demands in different regions of the state space. It is shown that the highspeed nonsingular terminal switched sliding mode(HNT-SSM)which is the representation of different control demands and enforced by the HNT-SSMC has the property of global highspeed convergence compared with the nonsingular fast terminal sliding mode(NFTSM), and provides the global non-singularity.The simulation study of an application example is carried out to validate the effectiveness of the proposed strategy.
文摘This paper presents an entire fixed-time disturbance observer-based global terminal switching sliding mode control of robot manipulators,which has inner and external uncertainties.The entire fixed-time disturbance observer-based global terminal switching sliding mode control has the global finite-time reaching characteristic,the property that system convergence time can be prescribed,and the global robustness to uncertainties,with the entire fixed-time disturbance observer that accurately estimates uncertainties after a fixed time,despite the initial state.The joints of the control system can arrive at the prescribed joint angular position at the predefined joint angular speed at the prescribed time.
基金supported by the National Natural Science Foundation of China(Nos.61374012,61273083 and 61403028)
文摘This paper deals with the problem of non-fragile linear parameter-varying（LPV） H_∞ control for morphing aircraft with asynchronous switching.The switched LPV model of morphing aircraft is established by Jacobian linearization approach according to the nonlinear model.The data missing is taken into account in the link from sensors to controllers and the link from controllers to actuators,which satisfies Bernoulli distribution.The non-fragile switched LPV controllers are constructed with consideration of the uncertainties of controllers and asynchronous switching phenomenon.The parameter-dependent Lyapunov functional method and mode-dependent average dwell time（MDADT） method are combined to guarantee the stability and prescribed performance of the system.The sufficient conditions on the solvability of the problem are derived in the form of linear matrix inequalities（LMI）.In order to achieve higher efficiency of the designing process,an algorithm is applied to divide the whole set into subsets automatically.Simulation results are provided to verify the effectiveness and superiority of the method in the paper.
文摘In this paper, we proposed an output voltage stabilization of a DC-DC Zeta converter using hybrid control. We modeled the Zeta converter under continuous conduction mode operation. We derived a switching control law that brings the output voltage to the desired level. Due to infinite switching occurring at the desired level, we enhanced the switching control law by allowing a sizeable output voltage ripple. We derived mathematical models that allow one to choose the desired switching frequency. In practice, the existence of the non-ideal properties of the Zeta converter results in steady-state output voltage error. By analyzing the power loss in the zeta converter, we proposed an improved switching control law that eliminates the steady-state output voltage error. The effectiveness of the proposed method is illustrated with simulation results.
基金The National Natural Science Foundation of China(No.61273119,61374038,61473079)
文摘In order to design a suitable controller which can achieve accurate trajectory tracking and a good control performance, and guarantee the stability and robustness of a robot system due to external disturbances error and internal parameter variations, an adaptive switching control strategy is proposed. The proposed scheme is designed under the condition of bounded distances and consists of an adaptive switching law and a PD controller. Based on the Lyapunov stability theory, it is proved that the proposed scheme can guarantee the tracking performance of the robotic manipulator and is adapted to varying unknown loads. Simulations are carded out on a two-link robotic manipulator, which illustrate the feasibility and validity of the proposed control scheme and the robustness for variational payloads.
基金Supported by the National Natural Science Foundation of China(61374111)the Natural Science Foundation of Zhejiang Province(LY13F030006)Agricultural Key Program of Ningbo City(2014C10068)
文摘This paper proposes a switching multi-objective model predictive control(MOMPC) algorithm for constrained nonlinear continuous-time process systems.Different cost functions to be minimized in MPC are switched to satisfy different performance criteria imposed at different sampling times.In order to ensure recursive feasibility of the switching MOMPC and stability of the resulted closed-loop system,the dual-mode control method is used to design the switching MOMPC controller.In this method,a local control law with some free-parameters is constructed using the control Lyapunov function technique to enlarge the terminal state set of MOMPC.The correction term is computed if the states are out of the terminal set and the free-parameters of the local control law are computed if the states are in the terminal set.The recursive feasibility of the MOMPC and stability of the resulted closed-loop system are established in the presence of constraints and arbitrary switches between cost functions.Finally,implementation of the switching MOMPC controller is demonstrated with a chemical process example for the continuous stirred tank reactor.
文摘The primary sensor of astronomy observation satellite （AOS） is mounted on a gimbal base which connects directly with the satellite platform and has two degrees of freedom. Attitude control for AOS with a swinging sensor will be highlighted in this paper. Due to the non-negligible mass and length of the sensor, the internal motion between the satellite and the sensor will change the attitude, the position of center of mass and moment of inertia of the SYSTEM （consists of the satellite and the sen- sor）. According to moment of momentum theorem, a rigid two-body dynamic model is derived, which can he used to determine the inertial tensor of the SYSTEM. Modulating the satellite＇s present and desired quaternions results in quasi-Euler angles and normalizing these resultant parameters can ensure that the channel corresponding to each quasi-Euler angle is in the charge of each component of the control torque. Based on the normalized quasi-Euler angles, a switching attitude control law is proposed. With the control law, the corresponding phase trajectory will slide along the switching surface to the origin （corresponding to the desired states）. Simulation results show that the satellite can be controlled perfectly by thrusters with the proposed control law, even in the case of structural asymmetry and serious coupling between the control channels.
基金supported by the National Outstanding Youth Science Foundation(61125306)the National Natural Science Foundation of Major Research Plan(91016004+2 种基金61034002)the Specialized Research Fund for the Doctoral Program of Higher Education of China (20110092110020)the Scientific Research Foundation of Graduate School of Southeast University(YBJJ1103)
文摘A novel gain-scheduled switching control method for the longitudinal motion of a flexible air-breathing hypersonic vehicle （FAHV） is proposed. Firstly, velocity and altitude are selected as scheduling variables, a polytopic linear parameter varying （LPV） model is developed to represent the complex nonlinear longitudinal dynamics of the FAHV. Secondly, based on the obtained polytopic LPV model, the flight envelope is divided into four smaller subregions, and four gain-scheduled controllers are designed for these parameter subregions. Then, by the defined switching characteristic function, these gain-scheduled controllers are switched in order to guarantee the closed-loop FAHV system to be asymptotically stable and satisfy a given tracking error performance criterion. The condition of gain-scheduled switching controller synthesis is given in terms of linear matrix inequalities （LMIs） which can be easily solved by using standard software packages. Finally, simulation results show the effectiveness of the presented method.
基金supported by National Natural Science Foundation of China(Nos.51175084,51575111 and 51605093)Fujian Province Natural Science Foundation(No.2015J05121)Fuzhou University-Enterprise Cooperation Project(No.2015H6012)
文摘With the increasing number of human-robot interaction applications, robot control characteristics and their effects on safety as well as performance should be taken account into the robot control system. In this paper, a position and torque switching con- trol method was proposed to improve the robot safety and performance, when robots and humans work in the same space. The switch- ing control method includes two modes, the position control mode using a proportion-integral （PI） algorithm, and the torque control mode using sliding mode control （SMC） algorithm for eliminating swing. Under the normal condition, the robot works in position con- trol mode for trajectory tracking with quick response. Once the robot and human collide, the robot will switch to torque control mode immediately, and the impact force will be restricted within a safe range. When the robot and human detach, the robot will resume to po- sition control mode automatically. Moreover, for a better performance, the joint torque is detected fl＇om direct-current （DC） motor＇s cur- rent rather than the torque sensor. The experiment results show that the proposed approach is effective and feasible.
基金Acknowledgements The work was supported by National Natural Science Foundation of China under grant 50775037 and 51075071.
文摘Efficient walking is one of the main goals of researches on biped robots. A feasible way is to translate the understanding from human walking into robot walking, for example, an artificial control approach on a human like walking structure. In this paper, a walking pattern based on Center of Pressure （COP） switched and modeled after human walking is introduced firstly. Then, a parameterization method for the proposed walking gait is presented. In view of the complication, a multi-space planning method which divides the whole planning task into three sub-spaces, including simplified model space, work space and joint space, is proposed. Furthermore, a finite-state-based control method is also developed to implement the proposed walking pattern. The state switches of this method are driven by sensor events. For convincing verification, a 2D simulation system with a 9-1ink planar biped robot is developed. The simulation results exhibit an efficient walking gait.
基金This work was supported by the National Natural Science Foundation of China (No.60574013, 60274009), and the Natural Science Fundation ofLiaoning Province (No.20032020).
文摘This paper deals with the problem of switching between an open-loop estimator and a close-loop estimator for compensating transmission error and packet dropout of networked control systems. Switching impulse is considered in order to reduce the error between theory and application, a sufficient condition for exponential stabilization of networked control systems under a given switching rule is presented by multiple Lyapunov-like functions. These results are presented for both continuous-time and discrete-time domains. Controllers are designed by means of linear matrix inequalities. Sim- ulation results show the feasibility and efficiency of the proposed method.
基金Supported by National Natural Science Foundation of China(Grant Nos.52005441,51890885)open Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems(Grant No.GZKF-201906)+1 种基金Zhejiang Province Natural Science Foundation of China(Grant No.LQ21E050017)China Postdoctoral Science Foundation(Grant Nos.2021M692777,2021T140594).
文摘In hydraulic area,independent metering control(IMC)technology is an effective approach to improve system efficiency and control flexibility.In addition,digital hydraulic technology(DHT)has been verified as a reasonable method to optimize system dynamic performance.Integrating these two technologies into one component can combine their advantages together.However,few works focused on it.In this paper,a twin spools valve with switching technologycontrolled pilot stage(TSVSP)is presented,which applied DHT into its pilot stage while appending IMC into its main stage.Based on this prototype valve,a series of numerical and experiment analysis of its IMC performance with both simulated load and excavator boom cylinder are carried out.Results showed fast and robust performance of pressure and flow compound control with acceptable fluctuation phenomenon caused by switching technology.Rising time of flow response in excavator cylinder can be controlled within 200 ms,meanwhile,the recovery time of rod chamber pressure under suddenly changed condition is optimized within 250 ms.IMC system based on TSVSP can improve both dynamic performance and robust characteristics of the target actuator so it is practical in valve-cylinder system and can be applied in mobile machineries.
基金Natural Science Foundation of Gansu Province(Nos.18JR3RA130,2018C-11,2018A-022)Science Fund of Lanzhou Jiaotong University(No.2017022)。
文摘In order to realize the fault diagnosis of the control circuit of all-electronic computer interlocking system(ACIS)for railway signals,taking a five-wire switch electronic control module as an research object,we propose a method of selecting the sample set of the basic classifier by roulette method and realizing fault diagnosis by using SVM-AdaBoost.The experimental results show that the proportion of basic classifier samples affects classification accuracy,which reaches the highest when the proportion is 85%.When selecting the sample set of basic classifier by roulette method,the fault diagnosis accuracy is generally higher than that of the maximum weight priority method.When the optimal proportion 85%is taken,the accuracy is highest up to 96.3%.More importantly,this way can better adapt to the critical data and improve the anti-interference ability of the algorithm,and therefore it provides a basis for fault diagnosis of ACIS.
基金co-supported by National Outstanding Youth Science Foundation(No.61125306)National Natural Science Foundation of Major Research Plan(Nos.91016004,61034002)+1 种基金Research Fund for the Doctoral Program of Higher Education of China(No.20110092110020)the Scientific Research Foundation of Graduate School of Southeast University(No.YBJJ1103)
文摘This article proposes a linear parameter varying （LPV） switching tracking control scheme for a flexible air-breathing hypersonic vehicle （FAHV）. First, a polytopic LPV model is constructed to represent the complex nonlinear longitudinal model of the FAHV by using Jacobian linearization and tensor-product （T-P） model transformation approach. Second, for less conservative controller design purpose, the flight envelope is divided into four sub-regions and a non-fragile LPV controller is designed for each parameter sub-region. These non-fragile LPV controllers are then switched in order to guarantee the closed-loop FAHV system to be asymptotically stable and satisfy a specified performance criterion. The desired non-fragile LPV switching controller is found by solving a convex constraint problem which can be efficiently solved using available linear matrix inequality （LMI） techniques, and robust stability analysis of the closed-loop FAHV system is verified based on multiple Lypapunov functions （MLFs）. Finally, numerical simulations have demonstrated the effectiveness of the proposed approach.
基金supported by the Aeronautical Science Foundation of China(20175752045)。
文摘A tilt-rotor aircraft has three flight modes: helicopter mode, airplane mode and conversion mode. Unlike the traditional aircraft, the tilt-rotor aircraft, which combines the characteristics of helicopters and fixed-wing aircraft, is a complex multi-body system with the violent variation of the aerodynamic parameters. For these characteristics, a new smooth switching control scheme is provided for the tilt-rotor aircraft. First, the reference commands for airspeed and nacelle angles are calculated by analyzing the conversion corridor and the conversion path. Subsequently, based on the finite-time switching theorem, an average dwell time condition is designed to guarantee the stability in the switching process. Besides, considering the state vibrations and bumps may appear in switching points, the fuzzy weighted logic is employed to improve the system transient performance. For disturbance rejection, three extended state observers are designed separately to estimate the disturbances in the switched systems. Compared with the traditional auto disturbance rejection control and proportion integration differentiation control, this method overcomes the conservatism of wasting the whole model information. The control performances of robustness and smoothness are verified with simulation, which shows that the new smooth switching control scheme is more targeted and superior than the traditional design method.
