Reconfiguration of formation flying around a halo orbit of the Sun-Earth restricted three body system is investigated with impulse maneuvers. For a short time reconfiguration, the two-impulse maneuver is investigated ...Reconfiguration of formation flying around a halo orbit of the Sun-Earth restricted three body system is investigated with impulse maneuvers. For a short time reconfiguration, the two-impulse maneuver is investigated with both analytical and numerical methods and the Beginning-Ending (BE) method is proven to be an energy-optimal one of all two-impulse (TI) reconfigurations, and the energy consumption of BE is independent of the position of the chief spacecraft, and decreases with the reconfiguration time. Then, genetic algorithm is adopted to optimize the energy consumption. The results show that the optimal energy increases with radius difference between the initial and final orbits, and decreases with the reconfiguration time.展开更多
This paper develops a novel optimization method oriented to the resilience of multiple Unmanned Aerial Vehicle(multi-UAV)formations to achieve rapid and accurate reconfiguration under random attacks.First,a resilience...This paper develops a novel optimization method oriented to the resilience of multiple Unmanned Aerial Vehicle(multi-UAV)formations to achieve rapid and accurate reconfiguration under random attacks.First,a resilience metric is applied to reflect the effect and rapidity of multi-UAV formation resisting random attacks.Second,an optimization model based on a parameter optimization problem to maximize the system resilience is established.Third,an Adaptive Learning-based Pigeon-Inspired Optimization(ALPIO)algorithm is designed to optimize the resilience value.Finally,typical formation topologies with six UAVs are investigated as a case study to verify the proposed approach.The experimental results indicate that the proposed scheme can achieve resilience optimization for a multi-UAV formation reconfiguration by increasing the system resilience values to 97.53%and 81.4%after random attacks.展开更多
In this paper,an adaptive artificial potential function(AAPF)method is developed for spacecraft formation reconfiguration with multi-obstacle avoidance under navigation and control uncertainties.Furthermore,an improve...In this paper,an adaptive artificial potential function(AAPF)method is developed for spacecraft formation reconfiguration with multi-obstacle avoidance under navigation and control uncertainties.Furthermore,an improved Linear Quadratic Regular(ILQR)is proposed to track the reference trajectory and a Lyapunov-based method is employed to demonstrate the stability of the overall closed-loop system.Compared with the traditional APF method and the equal-collision-probability surface(ECPS)method,the AAPF method not only retains the advantages of APF method and ECPS method,such as low computational complexity,simple analytical control law and easy analytical validation progress,but also proposes a new APF to solve multi-obstacle avoidance problem considering the influence of the uncertainties.Moreover,the ILQR controller obtains high control accuracy to enhance the safe performance of the spacecraft formation reconfiguration.Finally,the effectiveness of the proposed AAPF method and the ILQR controller are verified by numerical simulations.展开更多
This paper studies Multi-modes control method for libration points formation establishment and reconfiguration. Firstly, relations between optimal impulse control and Floquet modes are investigated. Method of generati...This paper studies Multi-modes control method for libration points formation establishment and reconfiguration. Firstly, relations between optimal impulse control and Floquet modes are investigated. Method of generating modes is proposed. Characteristics of the mode coefficients stimulated at different time are also given. Studies show that coefficients of controlled modes can be classified into four types, and formation establishment and reeonfiguration can be achieved by multi-impulse control with the presented method of generating modes. Then, since libration points formation is generally unstable, mutli-modes keeping control method which can stabilize five Floquet modes simultaneously is proposed. Finally, simulation on formation establishment and reconfiguration are carried out by using method of generating modes and mutli-modes keeping control method. Results show that the proposed control method is effective and practical.展开更多
The process of formation reconfiguration for close-range satellite formation should take into account the risk of collisions between satellites.To this end,this paper presents a method to rapidly generate low-thrust c...The process of formation reconfiguration for close-range satellite formation should take into account the risk of collisions between satellites.To this end,this paper presents a method to rapidly generate low-thrust collision-avoidance trajectories in the formation reconfiguration using Finite Fourier Series(FFS).The FFS method can rapidly generate the collision-avoidance threedimensional trajectory.The results obtained by the FFS method are used as an initial guess in the Gauss Pseudospectral Method(GPM)solver to verify the applicability of the results.Compared with the GPM method,the FFS method needs very little computing time to obtain the results with very little difference in performance index.To verify the effectiveness,the proposed method is tested and validated by a formation control testbed.Three satellite simulators in the testbed are used to simulate two-dimensional satellite formation reconfiguration.The simulation and experimental results show that the FFS method can rapidly generate trajectories and effectively reduce the risk of collision between satellites.This fast trajectory generation method has great significance for on-line,constantly satellite formation reconfiguration.展开更多
The reconfigurable manufacturing system (RMS) is the next step in manufacturing, allowing the production of any quantity of highly customized and complex parts together with the benefits of mass production. In RMSs,...The reconfigurable manufacturing system (RMS) is the next step in manufacturing, allowing the production of any quantity of highly customized and complex parts together with the benefits of mass production. In RMSs, parts are grouped into families, each of which requires a specific system configuration. Initially system is configured to produce the first family of parts. Once it is finished, the system will be reconfigured in order to produce the second family, and so forth. The effectiveness of a RMS depends on the formation of the optimum set of part families addressing various recon figurability issues. The aim of this work is to establish a methodology for grouping parts into families for effective working of RMS. The methodology carried out in two phases. In the first phase, the correlation matrix is used as similarity coefficient matrix. In the second phase, agglomerative hier archical Kmeans algorithm is used for the parts family for mation resulting in an optimum set of part families for reconfigurable manufacturing system.展开更多
基金The project supported by the National Natural Science Foundation of China(10672084 and 10672084)The Special Science Foundation of the Doctoral Discipline of the Minstry of Education of China(20060003097)
文摘Reconfiguration of formation flying around a halo orbit of the Sun-Earth restricted three body system is investigated with impulse maneuvers. For a short time reconfiguration, the two-impulse maneuver is investigated with both analytical and numerical methods and the Beginning-Ending (BE) method is proven to be an energy-optimal one of all two-impulse (TI) reconfigurations, and the energy consumption of BE is independent of the position of the chief spacecraft, and decreases with the reconfiguration time. Then, genetic algorithm is adopted to optimize the energy consumption. The results show that the optimal energy increases with radius difference between the initial and final orbits, and decreases with the reconfiguration time.
基金supported by the National Defense Pre-Research Foundation of China(No.61400020109).
文摘This paper develops a novel optimization method oriented to the resilience of multiple Unmanned Aerial Vehicle(multi-UAV)formations to achieve rapid and accurate reconfiguration under random attacks.First,a resilience metric is applied to reflect the effect and rapidity of multi-UAV formation resisting random attacks.Second,an optimization model based on a parameter optimization problem to maximize the system resilience is established.Third,an Adaptive Learning-based Pigeon-Inspired Optimization(ALPIO)algorithm is designed to optimize the resilience value.Finally,typical formation topologies with six UAVs are investigated as a case study to verify the proposed approach.The experimental results indicate that the proposed scheme can achieve resilience optimization for a multi-UAV formation reconfiguration by increasing the system resilience values to 97.53%and 81.4%after random attacks.
基金The work was supported by the Major Program of National Nature Science Foundation of China(Grant Nos.61690210 and 61690213the National Science Foundation of China(Grant Nos.11725211,61503414,11302253,and 11702320)the Scientific Research Project of National University of Defense Technology(ZK16-03-20).
文摘In this paper,an adaptive artificial potential function(AAPF)method is developed for spacecraft formation reconfiguration with multi-obstacle avoidance under navigation and control uncertainties.Furthermore,an improved Linear Quadratic Regular(ILQR)is proposed to track the reference trajectory and a Lyapunov-based method is employed to demonstrate the stability of the overall closed-loop system.Compared with the traditional APF method and the equal-collision-probability surface(ECPS)method,the AAPF method not only retains the advantages of APF method and ECPS method,such as low computational complexity,simple analytical control law and easy analytical validation progress,but also proposes a new APF to solve multi-obstacle avoidance problem considering the influence of the uncertainties.Moreover,the ILQR controller obtains high control accuracy to enhance the safe performance of the spacecraft formation reconfiguration.Finally,the effectiveness of the proposed AAPF method and the ILQR controller are verified by numerical simulations.
基金supported by the National Natural Science Foundation of China(10702078)the Advance Research Program of National University of Defense Technology (JC08-01-05)
文摘This paper studies Multi-modes control method for libration points formation establishment and reconfiguration. Firstly, relations between optimal impulse control and Floquet modes are investigated. Method of generating modes is proposed. Characteristics of the mode coefficients stimulated at different time are also given. Studies show that coefficients of controlled modes can be classified into four types, and formation establishment and reeonfiguration can be achieved by multi-impulse control with the presented method of generating modes. Then, since libration points formation is generally unstable, mutli-modes keeping control method which can stabilize five Floquet modes simultaneously is proposed. Finally, simulation on formation establishment and reconfiguration are carried out by using method of generating modes and mutli-modes keeping control method. Results show that the proposed control method is effective and practical.
基金supported in part by the National Natural Science Foundation of China(Nos.11702072 and 11672093)。
文摘The process of formation reconfiguration for close-range satellite formation should take into account the risk of collisions between satellites.To this end,this paper presents a method to rapidly generate low-thrust collision-avoidance trajectories in the formation reconfiguration using Finite Fourier Series(FFS).The FFS method can rapidly generate the collision-avoidance threedimensional trajectory.The results obtained by the FFS method are used as an initial guess in the Gauss Pseudospectral Method(GPM)solver to verify the applicability of the results.Compared with the GPM method,the FFS method needs very little computing time to obtain the results with very little difference in performance index.To verify the effectiveness,the proposed method is tested and validated by a formation control testbed.Three satellite simulators in the testbed are used to simulate two-dimensional satellite formation reconfiguration.The simulation and experimental results show that the FFS method can rapidly generate trajectories and effectively reduce the risk of collision between satellites.This fast trajectory generation method has great significance for on-line,constantly satellite formation reconfiguration.
文摘The reconfigurable manufacturing system (RMS) is the next step in manufacturing, allowing the production of any quantity of highly customized and complex parts together with the benefits of mass production. In RMSs, parts are grouped into families, each of which requires a specific system configuration. Initially system is configured to produce the first family of parts. Once it is finished, the system will be reconfigured in order to produce the second family, and so forth. The effectiveness of a RMS depends on the formation of the optimum set of part families addressing various recon figurability issues. The aim of this work is to establish a methodology for grouping parts into families for effective working of RMS. The methodology carried out in two phases. In the first phase, the correlation matrix is used as similarity coefficient matrix. In the second phase, agglomerative hier archical Kmeans algorithm is used for the parts family for mation resulting in an optimum set of part families for reconfigurable manufacturing system.