Dear Editor,This letter is concerned with the problem of time-varying formation tracking for heterogeneous multi-agent systems(MASs) under directed switching networks. For this purpose, our first step is to present so...Dear Editor,This letter is concerned with the problem of time-varying formation tracking for heterogeneous multi-agent systems(MASs) under directed switching networks. For this purpose, our first step is to present some sufficient conditions for the exponential stability of a particular category of switched systems.展开更多
This paper tackles the robust leaderless Time-Varying Formation(TVF)control problem for the Unmanned Aerial Vehicle(UAV)swarm system with Lipschitz nonlinear dynamics,external disturbances and directed switching topol...This paper tackles the robust leaderless Time-Varying Formation(TVF)control problem for the Unmanned Aerial Vehicle(UAV)swarm system with Lipschitz nonlinear dynamics,external disturbances and directed switching topologies.In comparison with the previous achievements on formation control problems,the UAV swarm system with Lipschitz nonlinear dynamics can accomplish the pre-designed TVF while tracking a pre-given trajectory which is produced by a virtual leader UAV in the presence of external disturbances.Firstly,by applying the consensus theory,a TVF controller is developed with the local neighborhood status information,the errors of real time status of all UAVs,the expected formation configuration and the pre-given trajectory under directed switching topologies.Secondly,through a certain matrix variable substitution,the UAV swarm system formation control issue is transformed into a lower dimensional asymptotically stable control issue.Thirdly,by introducing the minimum dwell time,the design steps of formation control algorithm are further acquired.In the meantime,the stability of the UAV swarm system is analyzed through the construction of a piecewise continuous Lyapunov functional and via the Linear Matrix Inequalities(LMIs)method.Finally,the comparison results of a numerical simulation are elaborated to verify the validity of the proposed approach.展开更多
This study investigates cooperative guidance problems for multiple missiles with fixed and switching directed communication topologies. A two-step guidance strategy is proposed to realize the simultaneous attack. In t...This study investigates cooperative guidance problems for multiple missiles with fixed and switching directed communication topologies. A two-step guidance strategy is proposed to realize the simultaneous attack. In the first step, a distributed cooperative guidance law is designed using local neighboring information for multiple missiles to achieve consensus on range-to-go and leading angle. The second step begins when the consensus of multiple missiles is realized. During the second step, multiple missiles disconnect from each other and hit the target using the proportional navigation guidance law. First, based on the local neighboring communications, a sufficient condition for multiple missiles to realize simultaneous attack with a fixed communication topology is presented, where the topology is only required to have a directed spanning tree. Then,the results are extended to the case of switching communication topologies. Finally, numerical simulations are provided to validate the theoretical results.展开更多
A consensus algorithm proposed in the paper is applied to tackle remarkable problems of unmeasurable velocities,the environmental disturbances, and the limited communication environment for the multiple unmanned under...A consensus algorithm proposed in the paper is applied to tackle remarkable problems of unmeasurable velocities,the environmental disturbances, and the limited communication environment for the multiple unmanned underwater vehicles(multi-UUVs). Firstly, for a complex nonlinear and coupled model of the unmanned underwater vehicle(UUV), a technique of feedback linearization is developed to transform the nonlinear UUV model into a secondorder integral UUV model. Secondly, to address the problem of the unavailable velocity information and environmental disturbances for the multi-UUVs system, we design a distributed extended state observer(DESO) to estimate the unmeasurable velocities and environmental disturbances using the relative position information. Finally,we propose a protocol based on the estimation information from the DESO and demonstrate that the multi-UUVs system with the switching directed topologies under the protocol can reach consensus asymptotically. The theoretical result proposed in the literature is verified by one numerical example.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.
Recently,switched control systems have been attracting much attention in 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 in 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. For survival,natural biological systems switch in strategies in accordance to environmental changes. For improved perfor-mance , switching has been extensively utilized/exploited in many engineering systems such as electronics, power systems, and traffic control,among others.In addition,switched behaviors exhibit in social systems.展开更多
An electromagnetically induced transparency(EIT) in metamaterial resonator with two bright modes and one dark mode at the terahertz(THz) band is numerically and experimentally demonstrated. Different from two kinds of...An electromagnetically induced transparency(EIT) in metamaterial resonator with two bright modes and one dark mode at the terahertz(THz) band is numerically and experimentally demonstrated. Different from two kinds of the traditional passive modulations, our design can realize the passive modulation of EIT phenomenon by adding another bright mode resonator. Simulated and experimental results show that the transmission peak varies for incident THz waves with different polarization directions due to its asymmetric structure, which provides a novel way to realize high efficiency switch and modulation.展开更多
Based on the spatial modulation of active Raman gain,a two-dimensional gain cross-grating is theoretically proposed.As the probe field propagates along the z direction and passes through the intersectant region of the...Based on the spatial modulation of active Raman gain,a two-dimensional gain cross-grating is theoretically proposed.As the probe field propagates along the z direction and passes through the intersectant region of the two orthogonal standingwave fields in the x-y plane,it can be effectively diffracted into the high-order directions,and the zero-order diffraction intensity is amplified at the same time.In comparison with the two-dimensional electromagnetically induced cross-grating based on electromagnetically induced transparency,the two-dimensional gain cross-grating has much higher diffraction intensities in the first-order and the high-order directions.Hence,it is more suitable to be utilized as all-optical switching and routing in optical networking and communication.展开更多
By using poled-polymer/silicon slot waveguides in the active region and the Pockels effect of the poled-polymer,we propose a kind of Mach-Zehnder interferometer(MZI) electro-optic(EO) switch operated at 1 550 nm.Struc...By using poled-polymer/silicon slot waveguides in the active region and the Pockels effect of the poled-polymer,we propose a kind of Mach-Zehnder interferometer(MZI) electro-optic(EO) switch operated at 1 550 nm.Structural parameters are optimized for realizing normal switching function.Dependencies of switching characteristics on the slot waveguide parameters are investigated.For the silicon strip with dimension of 170 nm×300 nm,as the slot width varies from 50 nm to 100 nm,the switching voltage can be as low as 1.0 V with active region length of only 0.17–0.35 mm,and the length of the whole device is only about 770–950 μm.The voltage-length product of this switching structure is only 0.17–0.35 V·mm,and it is at least 19–40 times smaller than that of the traditional polymer MZI EO switch,which is 6.69 V·mm.Compared with our previously reported MZI EO switches,this switch exhibits some superior characteristics,including low switching voltage,compact device size and small wavelength dependency.展开更多
Achieving asymptotical cooperative goal for multi-agent systems(MASs)with non-autonomous leaders(i.e.,leaders with nonzero inputs)is a critical but challenging issue.Traditional approach is to use discontinuous contro...Achieving asymptotical cooperative goal for multi-agent systems(MASs)with non-autonomous leaders(i.e.,leaders with nonzero inputs)is a critical but challenging issue.Traditional approach is to use discontinuous controllers which may cause chattering phenomenon in practical applications.How to achieve the asymptotical goal via a chattering free cooperative controller remains to be open so far.In this paper,an adaptive continuous controller is designed to achieve zero error consensus tracking in multiple Lur’e systems with a non-autonomous leader under directed switching topology.Firstly,an unknown input observer(UIO)based on relative outputs is given to estimate the relative full states.Then an adaptive continuous controller is designed by introducing a decay function which remains positive into the term that plays the role of eliminating the impacts of leader’s nonzero inputs.Secondly,by using multiple Lyapunov functions(MLFs)technique,it is proven that zero error consensus tracking can be achieved if the average dwell time(ADT)is greater than a positive threshold.Finally,theoretical result is verified by performing simulations on Chua’s circuits.Compared with existing work,the proposed controller can not only achieve asymptotical consensus,but also is chattering free.展开更多
基金supported in part by the National Natural Science Foundation of China(62273255,62350003,62088101)the Shanghai Science and Technology Cooperation Project(22510712000,21550760900)+1 种基金the Shanghai Municipal Science and Technology Major Project(2021SHZDZX0100)the Fundamental Research Funds for the Central Universities
文摘Dear Editor,This letter is concerned with the problem of time-varying formation tracking for heterogeneous multi-agent systems(MASs) under directed switching networks. For this purpose, our first step is to present some sufficient conditions for the exponential stability of a particular category of switched systems.
基金co-supported by the Key-area Research and Development Program of Guangdong ProvinceChina(No.2019B090915001)+2 种基金National Key R&D Program of China(No.2018YFB1308000),National Natural Science Funds of China(Nos.61772508,U1913202,U1813205,U1713213)CAS Key Technology Talent Program,Shenzhen Technology ProjectChina(Nos.JCYJ20180507182610734,JSGG20191129094012321).
文摘This paper tackles the robust leaderless Time-Varying Formation(TVF)control problem for the Unmanned Aerial Vehicle(UAV)swarm system with Lipschitz nonlinear dynamics,external disturbances and directed switching topologies.In comparison with the previous achievements on formation control problems,the UAV swarm system with Lipschitz nonlinear dynamics can accomplish the pre-designed TVF while tracking a pre-given trajectory which is produced by a virtual leader UAV in the presence of external disturbances.Firstly,by applying the consensus theory,a TVF controller is developed with the local neighborhood status information,the errors of real time status of all UAVs,the expected formation configuration and the pre-given trajectory under directed switching topologies.Secondly,through a certain matrix variable substitution,the UAV swarm system formation control issue is transformed into a lower dimensional asymptotically stable control issue.Thirdly,by introducing the minimum dwell time,the design steps of formation control algorithm are further acquired.In the meantime,the stability of the UAV swarm system is analyzed through the construction of a piecewise continuous Lyapunov functional and via the Linear Matrix Inequalities(LMIs)method.Finally,the comparison results of a numerical simulation are elaborated to verify the validity of the proposed approach.
基金co-supported by the National Natural Science Foundation of China (Nos. 61503009, 61333011 and 61421063)the Aeronautical Science Foundation of China (No. 2016ZA51005)+1 种基金the Fundamental Research Funds for the Central Universities of China (No. YWF-14-RSC-101)the Excellence Foundation of BUAA for Ph.D. Students (No.2017016)
文摘This study investigates cooperative guidance problems for multiple missiles with fixed and switching directed communication topologies. A two-step guidance strategy is proposed to realize the simultaneous attack. In the first step, a distributed cooperative guidance law is designed using local neighboring information for multiple missiles to achieve consensus on range-to-go and leading angle. The second step begins when the consensus of multiple missiles is realized. During the second step, multiple missiles disconnect from each other and hit the target using the proportional navigation guidance law. First, based on the local neighboring communications, a sufficient condition for multiple missiles to realize simultaneous attack with a fixed communication topology is presented, where the topology is only required to have a directed spanning tree. Then,the results are extended to the case of switching communication topologies. Finally, numerical simulations are provided to validate the theoretical results.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 51679057 and 51709062)Heilongjiang Province Outstanding Youth Fund (Grant No. J2016JQ0052)+2 种基金Equipment Preresearch Key Lab Fund (Grant No. 614221580107)China Postdoctoral Science Foundation (Grant No. 2019M651265)Harbin Science and Technology Talent Research Special Fund (Grant No.2017RAQXJ150)。
文摘A consensus algorithm proposed in the paper is applied to tackle remarkable problems of unmeasurable velocities,the environmental disturbances, and the limited communication environment for the multiple unmanned underwater vehicles(multi-UUVs). Firstly, for a complex nonlinear and coupled model of the unmanned underwater vehicle(UUV), a technique of feedback linearization is developed to transform the nonlinear UUV model into a secondorder integral UUV model. Secondly, to address the problem of the unavailable velocity information and environmental disturbances for the multi-UUVs system, we design a distributed extended state observer(DESO) to estimate the unmeasurable velocities and environmental disturbances using the relative position information. Finally,we propose a protocol based on the estimation information from the DESO and demonstrate that the multi-UUVs system with the switching directed topologies under the protocol can reach consensus asymptotically. The theoretical result proposed in the literature is verified by one numerical example.
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.
文摘Recently,switched control systems have been attracting much attention in 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. For survival,natural biological systems switch in strategies in accordance to environmental changes. For improved perfor-mance , switching has been extensively utilized/exploited in many engineering systems such as electronics, power systems, and traffic control,among others.In addition,switched behaviors exhibit in social systems.
基金supported by the National Basic Research Program of China(No.2014CB339800)the National Natural Science Foundation of China(Nos.61671491 and 61505088)+2 种基金the Natural Science Foundation of Tianjin(No.15JCQNJC02100)the Science and Technology Program of Tianjin(No.13RCGFGX01127)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20131201120004)
文摘An electromagnetically induced transparency(EIT) in metamaterial resonator with two bright modes and one dark mode at the terahertz(THz) band is numerically and experimentally demonstrated. Different from two kinds of the traditional passive modulations, our design can realize the passive modulation of EIT phenomenon by adding another bright mode resonator. Simulated and experimental results show that the transmission peak varies for incident THz waves with different polarization directions due to its asymmetric structure, which provides a novel way to realize high efficiency switch and modulation.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11274112 and 11347133)
文摘Based on the spatial modulation of active Raman gain,a two-dimensional gain cross-grating is theoretically proposed.As the probe field propagates along the z direction and passes through the intersectant region of the two orthogonal standingwave fields in the x-y plane,it can be effectively diffracted into the high-order directions,and the zero-order diffraction intensity is amplified at the same time.In comparison with the two-dimensional electromagnetically induced cross-grating based on electromagnetically induced transparency,the two-dimensional gain cross-grating has much higher diffraction intensities in the first-order and the high-order directions.Hence,it is more suitable to be utilized as all-optical switching and routing in optical networking and communication.
基金supported by the National Natural Science Foundation of China(Nos.61107021,61177027 and 61077074)the Ministry of Education of China(Nos.20110061120052 and 20120061130008)the Science and Technology Department of Jilin Province of China(No.20130522161JH)
文摘By using poled-polymer/silicon slot waveguides in the active region and the Pockels effect of the poled-polymer,we propose a kind of Mach-Zehnder interferometer(MZI) electro-optic(EO) switch operated at 1 550 nm.Structural parameters are optimized for realizing normal switching function.Dependencies of switching characteristics on the slot waveguide parameters are investigated.For the silicon strip with dimension of 170 nm×300 nm,as the slot width varies from 50 nm to 100 nm,the switching voltage can be as low as 1.0 V with active region length of only 0.17–0.35 mm,and the length of the whole device is only about 770–950 μm.The voltage-length product of this switching structure is only 0.17–0.35 V·mm,and it is at least 19–40 times smaller than that of the traditional polymer MZI EO switch,which is 6.69 V·mm.Compared with our previously reported MZI EO switches,this switch exhibits some superior characteristics,including low switching voltage,compact device size and small wavelength dependency.
基金supported by the National Natural Science Foundation of China(Grant Nos.62003003 and 62073076)the Natural Science Foundation of Anhui Province(Grant No.2008085QF304)the Talent Programme of Anhui Province for Young Scholars。
文摘Achieving asymptotical cooperative goal for multi-agent systems(MASs)with non-autonomous leaders(i.e.,leaders with nonzero inputs)is a critical but challenging issue.Traditional approach is to use discontinuous controllers which may cause chattering phenomenon in practical applications.How to achieve the asymptotical goal via a chattering free cooperative controller remains to be open so far.In this paper,an adaptive continuous controller is designed to achieve zero error consensus tracking in multiple Lur’e systems with a non-autonomous leader under directed switching topology.Firstly,an unknown input observer(UIO)based on relative outputs is given to estimate the relative full states.Then an adaptive continuous controller is designed by introducing a decay function which remains positive into the term that plays the role of eliminating the impacts of leader’s nonzero inputs.Secondly,by using multiple Lyapunov functions(MLFs)technique,it is proven that zero error consensus tracking can be achieved if the average dwell time(ADT)is greater than a positive threshold.Finally,theoretical result is verified by performing simulations on Chua’s circuits.Compared with existing work,the proposed controller can not only achieve asymptotical consensus,but also is chattering free.
