For an uncertain fixed-wing unmanned aerial vehicle(UAV)system subject to composite disturbances,this paper proposes a disturbance observer-based dynamic output feedback resilient control scheme.Firstly,a coordination...For an uncertain fixed-wing unmanned aerial vehicle(UAV)system subject to composite disturbances,this paper proposes a disturbance observer-based dynamic output feedback resilient control scheme.Firstly,a coordination disturbance observer composed of multiple disturbance observers is designed to estimate external disturbances in real time,which makes the selection of observer gains more flexible.Then,L_(2)−L_(∞)performance index is introduced to suppress energybounded disturbances.Subsequently,according to the disturbance observer method,dynamic output feedback control technique,and resilient control theory,a resilient tracking controller for the fixed-wing UAV is developed.Through Lyapunov stability analysis,the closed-loop augmented system is robust asymptotically stable and satisfies L_(2)−L_(∞)index performance criteria.Finally,simulation outcomes indicate that the suggested control approach demonstrates excellent anti-disturbance performance,effectively enhancing the control accuracy and robustness of the fixed-wing UAV in complex environments.展开更多
Hexaphyrins are one of the most studied expanded porphyrins that show intriguing electronic structure and coordination abilities in the past decades.However,core-modified hexaphyrins especially for benzene-replaced he...Hexaphyrins are one of the most studied expanded porphyrins that show intriguing electronic structure and coordination abilities in the past decades.However,core-modified hexaphyrins especially for benzene-replaced hexaphyrins are much less explored.Herein,we revisit the dibenzihexaphyrin system and demonstrate how to achieve the hexaphyrin-like organometallic nature of a benzene-replaced expanded porphyrin.For the“true”di-m-benzihexaphyrin 2,metal complex with anticipated CCNN coordination is not realized probably due to the steric hindrance.Further,we synthesized an internally linked dibenzihexaphyrin(3)with a direct carbon–carbon bond between two phenylenes.As prepared,3 has a strained biphenyl unit and can effectively coordinate two Cu(III)ions with CCNN coordination.This sharp contrast underscores the critical importance of the formed preorganized corrole-like adj-CCNN cavities after linking two flanking phenylenes.3 can also act as a bidentate ligand like traditional hexaphyrin,enabling the formation of an even more strained bis-Rh(I)complex.The electronic structures and photophysical properties of the free base and metal complexes are systematically studied by steady state absorption and fstransient absorptions(fs-TA)spectroscopies,as well as DFTcalculations.Notably,3 can be regarded as a hexaphyrin-sized backto-back fused bis-dicarbacorrole,which stands as the smallest fused carbaporphyrinoid array prepared to date.展开更多
基金supported in part by the National Natural Science Foundation of China[grant number 62533012]the Hong Kong,Macao and Taiwan Science and Technology Cooperation Project of Special Foundation in Jiangsu Science and Technology Plan[grant number BZ2023057].
文摘For an uncertain fixed-wing unmanned aerial vehicle(UAV)system subject to composite disturbances,this paper proposes a disturbance observer-based dynamic output feedback resilient control scheme.Firstly,a coordination disturbance observer composed of multiple disturbance observers is designed to estimate external disturbances in real time,which makes the selection of observer gains more flexible.Then,L_(2)−L_(∞)performance index is introduced to suppress energybounded disturbances.Subsequently,according to the disturbance observer method,dynamic output feedback control technique,and resilient control theory,a resilient tracking controller for the fixed-wing UAV is developed.Through Lyapunov stability analysis,the closed-loop augmented system is robust asymptotically stable and satisfies L_(2)−L_(∞)index performance criteria.Finally,simulation outcomes indicate that the suggested control approach demonstrates excellent anti-disturbance performance,effectively enhancing the control accuracy and robustness of the fixed-wing UAV in complex environments.
基金supported by the National Natural Science Foundation of China(22471023 to X.-S.Ke and U2230203 to W.Zhang)the startup funding from Beijing Normal University(BNU)(312232114 to X.-S.Ke)。
文摘Hexaphyrins are one of the most studied expanded porphyrins that show intriguing electronic structure and coordination abilities in the past decades.However,core-modified hexaphyrins especially for benzene-replaced hexaphyrins are much less explored.Herein,we revisit the dibenzihexaphyrin system and demonstrate how to achieve the hexaphyrin-like organometallic nature of a benzene-replaced expanded porphyrin.For the“true”di-m-benzihexaphyrin 2,metal complex with anticipated CCNN coordination is not realized probably due to the steric hindrance.Further,we synthesized an internally linked dibenzihexaphyrin(3)with a direct carbon–carbon bond between two phenylenes.As prepared,3 has a strained biphenyl unit and can effectively coordinate two Cu(III)ions with CCNN coordination.This sharp contrast underscores the critical importance of the formed preorganized corrole-like adj-CCNN cavities after linking two flanking phenylenes.3 can also act as a bidentate ligand like traditional hexaphyrin,enabling the formation of an even more strained bis-Rh(I)complex.The electronic structures and photophysical properties of the free base and metal complexes are systematically studied by steady state absorption and fstransient absorptions(fs-TA)spectroscopies,as well as DFTcalculations.Notably,3 can be regarded as a hexaphyrin-sized backto-back fused bis-dicarbacorrole,which stands as the smallest fused carbaporphyrinoid array prepared to date.
