This paper proposes a distributed event-triggered control(ETC)framework to address cooperative target fencing challenges in UAV swarm.The proposed architecture eliminates the reliance on preset formation parameters wh...This paper proposes a distributed event-triggered control(ETC)framework to address cooperative target fencing challenges in UAV swarm.The proposed architecture eliminates the reliance on preset formation parameters while achieving multi-objective cooperative control for target fencing,network connectivity preservation,collision avoidance,and communication efficiency optimization.Firstly,a differential state observer is constructed to obtain the target's unmeasurable states.Secondly,leveraging swarm selforganization principles,a geometric-constraint-free distributed fencing controller is designed by integrating potential field methods with consensus theory.The controller dynamically adjusts inter-UAV distances via single potential function,enabling coordinated optimization of persistent network connectivity and collision-free motion during target fencing.Thirdly,a dual-threshold ETC mechanism based on velocity consensus deviation and fencing error is proposed,which can be triggered based on task features to dynamically adjust the communication frequency,significantly reduce the communication burden and exclude Zeno behavior.Theoretical analysis demonstrates the stability of closed-loop systems.Multi-scenario simulations show that the proposed method can achieve robust fencing under target maneuverability,partial UAV failures,and communication disturbances.展开更多
By scanning and transmission electron microscopy, leukemlc celb were obwrved after CFU-Mix culture. Even though granulocytlc growth factor, erythropoietin and lymphocytlc growth factor were added at vitor, acute leuke...By scanning and transmission electron microscopy, leukemlc celb were obwrved after CFU-Mix culture. Even though granulocytlc growth factor, erythropoietin and lymphocytlc growth factor were added at vitor, acute leukemlc celb still showed defects In differentiation and maturation. These were characterized by abnormal colony which consisted of smooth cells, bizarre shape, nuclear-cytoplasmic asynchrony In development, and appearance of nuclear bleb. However, chronic myelogenous leukemlc celb were more nature than the acute ones, manifesting in normal colony with finger- like projections and ruffled membrane. Macrophages and eosinophils could be observed. It b suggested that there b a difference In differentiation between acute and chronic leukemia cells.展开更多
Dynamic characteristics and tracking precision are studied in the photoelectric tracking system and a linear active disturbance rejection control( LADRC) scheme is proposed for position loop. A current and speed contr...Dynamic characteristics and tracking precision are studied in the photoelectric tracking system and a linear active disturbance rejection control( LADRC) scheme is proposed for position loop. A current and speed controller is designed by a transfer function model,which is obtained by adaptive differential evolution. Model error,friction and nonlinear factor existing in position loop are treated as ‘disturbance',which is estimated and compensated by generalized proportional integral( GPI)observer. Comparative results are provided to demonstrate the remarkable performance of the proposed method. It turns out that the proposed scheme is successful and has superior features,such as quick dynamic response,low overshoot and high tracking precision. Furthermore,with the proposed method,friction is suppressed effectively.展开更多
文摘This paper proposes a distributed event-triggered control(ETC)framework to address cooperative target fencing challenges in UAV swarm.The proposed architecture eliminates the reliance on preset formation parameters while achieving multi-objective cooperative control for target fencing,network connectivity preservation,collision avoidance,and communication efficiency optimization.Firstly,a differential state observer is constructed to obtain the target's unmeasurable states.Secondly,leveraging swarm selforganization principles,a geometric-constraint-free distributed fencing controller is designed by integrating potential field methods with consensus theory.The controller dynamically adjusts inter-UAV distances via single potential function,enabling coordinated optimization of persistent network connectivity and collision-free motion during target fencing.Thirdly,a dual-threshold ETC mechanism based on velocity consensus deviation and fencing error is proposed,which can be triggered based on task features to dynamically adjust the communication frequency,significantly reduce the communication burden and exclude Zeno behavior.Theoretical analysis demonstrates the stability of closed-loop systems.Multi-scenario simulations show that the proposed method can achieve robust fencing under target maneuverability,partial UAV failures,and communication disturbances.
文摘By scanning and transmission electron microscopy, leukemlc celb were obwrved after CFU-Mix culture. Even though granulocytlc growth factor, erythropoietin and lymphocytlc growth factor were added at vitor, acute leukemlc celb still showed defects In differentiation and maturation. These were characterized by abnormal colony which consisted of smooth cells, bizarre shape, nuclear-cytoplasmic asynchrony In development, and appearance of nuclear bleb. However, chronic myelogenous leukemlc celb were more nature than the acute ones, manifesting in normal colony with finger- like projections and ruffled membrane. Macrophages and eosinophils could be observed. It b suggested that there b a difference In differentiation between acute and chronic leukemia cells.
基金Supported by the National High Technology Research and Development Programme of China(No.2015AA8082065)the National Natural Science Foundation of China(No.61205143)
文摘Dynamic characteristics and tracking precision are studied in the photoelectric tracking system and a linear active disturbance rejection control( LADRC) scheme is proposed for position loop. A current and speed controller is designed by a transfer function model,which is obtained by adaptive differential evolution. Model error,friction and nonlinear factor existing in position loop are treated as ‘disturbance',which is estimated and compensated by generalized proportional integral( GPI)observer. Comparative results are provided to demonstrate the remarkable performance of the proposed method. It turns out that the proposed scheme is successful and has superior features,such as quick dynamic response,low overshoot and high tracking precision. Furthermore,with the proposed method,friction is suppressed effectively.
