In this work,we sought to investigate constrained docking control during shipborne SideArm recovery of an Unmanned Aerial Vehicle(UAV)under preassigned safe docking constraints,rough ocean environments,and different i...In this work,we sought to investigate constrained docking control during shipborne SideArm recovery of an Unmanned Aerial Vehicle(UAV)under preassigned safe docking constraints,rough ocean environments,and different initial positions.The aim was to solve the UAV tracking-lag problem that manifests when attempting to dock with a rapidly moving SideArm and to improve the accuracy and rapidity of docking.First,together with the formulations of the shipborne SideArm system and environmental airflows,the affine nonlinear dynamics of the hook was established to reduce tracking lag.Then,echo state network approximators with good approximation capacity and low computational consumption were designed to accurately approximate the UAV’s unknown nonlinear dynamics.With feedforward compensation provided by these approximators,a nonlinear-mapping-based constrained docking control law was developed for shipborne SideArm recovery of UAVs.This approach to controlling the docking trajectory and the forward docking speed of the UAV can achieve rapid and exact docking with a moving SideArm,without violating the preassigned safe docking-constraint envelopes.Simulations under different docking scenarios were used to validate the effectiveness and advantages of the proposed docking-control algorithm.展开更多
We develop and experimentally demonstrate a phase-sensitive continuous variable quantum key distribution system with improved secure key rate.This is achieved using multimode coherent states with phase-conjugated subc...We develop and experimentally demonstrate a phase-sensitive continuous variable quantum key distribution system with improved secure key rate.This is achieved using multimode coherent states with phase-conjugated subcarrier modulation and phase-sensitive detection.The local oscillator for phase-sensitive detection is regenerated from a polarization-multiplexed carrier wave via optical injection locking.The proposed scheme has a higher classical information capacity at a given number of received photons and exhibits a higher secure key rate when applying the security analysis of the GG02 protocol.Experimental results confirm the higher secret key rate and better excess noise tolerance of the new scheme compared to the typical implementation of GG02.展开更多
基金This study was supported by the National Key Laboratory of Science and Technology on UAV in NWPU,China(No.2022-JCJQ-LB-071)the National Natural Science Foundations of China(No.61903190)+2 种基金the Aeronautical Science Foundation(N2022Z023052003)the Fundamental Research Funds for the Central Universities,China(No.NS2023016)the Postgraduate Research&Practice Innovation Program of NUAA,China(No.xcxjh20230311).
文摘In this work,we sought to investigate constrained docking control during shipborne SideArm recovery of an Unmanned Aerial Vehicle(UAV)under preassigned safe docking constraints,rough ocean environments,and different initial positions.The aim was to solve the UAV tracking-lag problem that manifests when attempting to dock with a rapidly moving SideArm and to improve the accuracy and rapidity of docking.First,together with the formulations of the shipborne SideArm system and environmental airflows,the affine nonlinear dynamics of the hook was established to reduce tracking lag.Then,echo state network approximators with good approximation capacity and low computational consumption were designed to accurately approximate the UAV’s unknown nonlinear dynamics.With feedforward compensation provided by these approximators,a nonlinear-mapping-based constrained docking control law was developed for shipborne SideArm recovery of UAVs.This approach to controlling the docking trajectory and the forward docking speed of the UAV can achieve rapid and exact docking with a moving SideArm,without violating the preassigned safe docking-constraint envelopes.Simulations under different docking scenarios were used to validate the effectiveness and advantages of the proposed docking-control algorithm.
基金National Key Research and Development Program of China(2018YFB1801804)National Natural Science Foundation of China(61935011,62227819,U2001601)Key-Area Research and Development Program of Guangdong Province(2020B0303040001)。
文摘We develop and experimentally demonstrate a phase-sensitive continuous variable quantum key distribution system with improved secure key rate.This is achieved using multimode coherent states with phase-conjugated subcarrier modulation and phase-sensitive detection.The local oscillator for phase-sensitive detection is regenerated from a polarization-multiplexed carrier wave via optical injection locking.The proposed scheme has a higher classical information capacity at a given number of received photons and exhibits a higher secure key rate when applying the security analysis of the GG02 protocol.Experimental results confirm the higher secret key rate and better excess noise tolerance of the new scheme compared to the typical implementation of GG02.
