Current applications using single unmanned vehicle have been gradually extended to multiple ones due to their increased efficiency in mission accomplishment, expanded coverage areas and ranges, as well as enhanced sys...Current applications using single unmanned vehicle have been gradually extended to multiple ones due to their increased efficiency in mission accomplishment, expanded coverage areas and ranges, as well as enhanced system reliability. This paper presents a flocking control method with application to a fleet of unmanned quadrotor helicopters (UQHs). Three critical characteristics of formation keeping, collision avoidance, and velocity matching have been taken into account in the algorithm development to make it capable of accomplishing the desired objectives (like forest/pipeline surveillance) by safely and efficiently operating a group of UQHs. To achieve these, three layered system design philosophy is considered in this study. The first layer is the flocking controller which is designed based on the kinematics of UQH. The modified Cucker and Smale model is used for guaranteeing the convergence of UQHs to flocking, while a repelling force between each two UQHs is also added for ensuring a specified safety distance. The second layer is the motion controller which is devised based on the kinetics of UQH by employing the augmented state-feedback control approach to greatly minimize the steady-state error. The last layer is the UQH system along with its actuators. Two primary contributions have been made in this work: first, different from most of the existing works conducted on agents with double integrator dynamics, a new flocking control algorithm has been designed and implemented on a group of UQHs with nonlinear dynamics. Furthermore, the constraint of fixed neighbouring distance in formation has been relaxed expecting to significantly reduce the complexity caused by the increase of agents number and provide more flexibility to the formation control. Extensive numerical simulations on a group of UQH nonlinear models have been carried out to verify the effectiveness of the proposed method.展开更多
This paper studies a flocking model in which the interaction between agents is described by a general local nonlinear function depending on the distance between agents. The existing analysis provided sufficient condit...This paper studies a flocking model in which the interaction between agents is described by a general local nonlinear function depending on the distance between agents. The existing analysis provided sufficient conditions for flocking under an assumption imposed on the system’s closed-loop states; however this assumption is hard to verify. To avoid this kind of assumption the authors introduce some new methods including large deviations theory and estimation of spectral radius of random geometric graphs. For uniformly and independently distributed initial states, the authors establish sufficient conditions and necessary conditions for flocking with large population. The results reveal that under some conditions, the critical interaction radius for flocking is almost the same as the critical radius for connectivity of the initial neighbor graph.展开更多
We study the existence and uniqueness problem for the nonhomogeneous pressureless Euler system with the initial density being a Radon measure. Our uniqueness result is obtained in the same space as the existence theor...We study the existence and uniqueness problem for the nonhomogeneous pressureless Euler system with the initial density being a Radon measure. Our uniqueness result is obtained in the same space as the existence theorem. Besides, by counterexample we prove that Huang-Wang’s energy condition is also necessary for our nonhomogeneous system.展开更多
In this paper, we study the flocking behavior of a thermodynamic Cucker–Smale model with local velocity interactions. Using the spectral gap of a connected stochastic matrix, together with an elaborate estimate on pe...In this paper, we study the flocking behavior of a thermodynamic Cucker–Smale model with local velocity interactions. Using the spectral gap of a connected stochastic matrix, together with an elaborate estimate on perturbations of a linearized system, we provide a sufficient framework in terms of initial data and model parameters to guarantee flocking. Moreover, it is shown that the system achieves a consensus at an exponential rate.展开更多
We study the global existence and uniqueness of a strong solution to the kinetic thermomechanical Cucker-Smale(for short,TCS) model coupled with Stokes equations in the whole space.The coupled system consists of the k...We study the global existence and uniqueness of a strong solution to the kinetic thermomechanical Cucker-Smale(for short,TCS) model coupled with Stokes equations in the whole space.The coupled system consists of the kinetic TCS equation for a particle ensemble and the Stokes equations for a fluid via a drag force.In this paper,we present a complete analysis of the existence of global-in-time strong solutions to the coupled model without any smallness restrictions on the initial data.展开更多
In this paper,the flocking behavior of a Cucker-Smale model with a leader and noise is studied in a finite time.The authors present a Cucker-Smale system with two nonlinear controls for a complex network with stochast...In this paper,the flocking behavior of a Cucker-Smale model with a leader and noise is studied in a finite time.The authors present a Cucker-Smale system with two nonlinear controls for a complex network with stochastic synchronization in probability.Based on the finite-time stability theory of stochastic differential equations,the sufficient conditions for the flocking of stochastic systems in a finite time are obtained by using the Lyapunov function method.Finally,the numerical simulation of the particle system is carried out for the leader and noise,and the correctness of the results is verified.展开更多
How to analyze flocking behaviors of a multi-agent system with local interaction functions is a challenging problem in theory.Motsch and Tadmor in 2011 also stressed the significance to assume that the interaction fun...How to analyze flocking behaviors of a multi-agent system with local interaction functions is a challenging problem in theory.Motsch and Tadmor in 2011 also stressed the significance to assume that the interaction function is rapidly decaying or cut-off at a finite distance(cf.Motsch and Tadmor in J.Stat.Phys.2011).In this paper,we study the flocking behavior of a Cucker–Smale type model with compactly supported interaction functions.Using properties of a connected stochastic matrix,together with an elaborate analysis on perturbations of a linearized system,we obtain a sufficient condition imposed only on model parameters and initial data to guarantee flocking.Moreover,it is shown that the system achieves flocking at an exponential rate.展开更多
Cucker-Smale系统中每个个体与其相邻个体的联系对其他个体产生有限的局部影响,最终实现全部个体状态一致。该系统被广泛应用于生态网络、控制理论、通信工程、模式识别和仿生学等领域。本文根据Cucker-Smale系统的控制研究现状,介绍了...Cucker-Smale系统中每个个体与其相邻个体的联系对其他个体产生有限的局部影响,最终实现全部个体状态一致。该系统被广泛应用于生态网络、控制理论、通信工程、模式识别和仿生学等领域。本文根据Cucker-Smale系统的控制研究现状,介绍了近期取得的理论成果,包括Cucker-Smale系统渐进和牵引蜂拥、带有噪声和时滞影响下的Cucker-Smale系统蜂拥、具有leader-follow关系的Cucker-Smale系统蜂拥。进一步详细介绍了牵引蜂拥及具有leader-follow关系的Cucker-Smale系统蜂拥控制的优点,同时给出下一步需要解决的具体问题。In the Cucker-Smale system, the interaction between each individual and its neighboring individuals exerts a limited local influence on other individuals, ultimately leading to consensus among all individuals. This system has been widely applied in various fields such as ecological networks, control theory, communication engineering, pattern recognition, and bionics. In this article, based on the current status of control research on the Cucker-Smale system, we introduce recent theoretical achievements, including asymptotic and pinning swarming of the Cucker-Smale system, swarming of the Cucker-Smale system with noise and time delay effects, and swarming of the Cucker-Smale system with leader-follow relationships. Further detailed introduction was given to the advantages of pinning swarming and the crowding control of the Cucker-Smale system with the leader-follow relationship while providing specific issues to be addressed in the next step.展开更多
文摘Current applications using single unmanned vehicle have been gradually extended to multiple ones due to their increased efficiency in mission accomplishment, expanded coverage areas and ranges, as well as enhanced system reliability. This paper presents a flocking control method with application to a fleet of unmanned quadrotor helicopters (UQHs). Three critical characteristics of formation keeping, collision avoidance, and velocity matching have been taken into account in the algorithm development to make it capable of accomplishing the desired objectives (like forest/pipeline surveillance) by safely and efficiently operating a group of UQHs. To achieve these, three layered system design philosophy is considered in this study. The first layer is the flocking controller which is designed based on the kinematics of UQH. The modified Cucker and Smale model is used for guaranteeing the convergence of UQHs to flocking, while a repelling force between each two UQHs is also added for ensuring a specified safety distance. The second layer is the motion controller which is devised based on the kinetics of UQH by employing the augmented state-feedback control approach to greatly minimize the steady-state error. The last layer is the UQH system along with its actuators. Two primary contributions have been made in this work: first, different from most of the existing works conducted on agents with double integrator dynamics, a new flocking control algorithm has been designed and implemented on a group of UQHs with nonlinear dynamics. Furthermore, the constraint of fixed neighbouring distance in formation has been relaxed expecting to significantly reduce the complexity caused by the increase of agents number and provide more flexibility to the formation control. Extensive numerical simulations on a group of UQH nonlinear models have been carried out to verify the effectiveness of the proposed method.
基金supported by the National Natural Science Foundation of China under Grant No.11688101,91634203,91427304,and 61673373the National Key Basic Research Program of China(973 Program)under Grant No.2016YFB0800404
文摘This paper studies a flocking model in which the interaction between agents is described by a general local nonlinear function depending on the distance between agents. The existing analysis provided sufficient conditions for flocking under an assumption imposed on the system’s closed-loop states; however this assumption is hard to verify. To avoid this kind of assumption the authors introduce some new methods including large deviations theory and estimation of spectral radius of random geometric graphs. For uniformly and independently distributed initial states, the authors establish sufficient conditions and necessary conditions for flocking with large population. The results reveal that under some conditions, the critical interaction radius for flocking is almost the same as the critical radius for connectivity of the initial neighbor graph.
文摘We study the existence and uniqueness problem for the nonhomogeneous pressureless Euler system with the initial density being a Radon measure. Our uniqueness result is obtained in the same space as the existence theorem. Besides, by counterexample we prove that Huang-Wang’s energy condition is also necessary for our nonhomogeneous system.
文摘In this paper, we study the flocking behavior of a thermodynamic Cucker–Smale model with local velocity interactions. Using the spectral gap of a connected stochastic matrix, together with an elaborate estimate on perturbations of a linearized system, we provide a sufficient framework in terms of initial data and model parameters to guarantee flocking. Moreover, it is shown that the system achieves a consensus at an exponential rate.
基金supported by the National Natural Science Foundation of China (12001033)。
文摘We study the global existence and uniqueness of a strong solution to the kinetic thermomechanical Cucker-Smale(for short,TCS) model coupled with Stokes equations in the whole space.The coupled system consists of the kinetic TCS equation for a particle ensemble and the Stokes equations for a fluid via a drag force.In this paper,we present a complete analysis of the existence of global-in-time strong solutions to the coupled model without any smallness restrictions on the initial data.
基金supported by the Natural Science Foundation of Heilongjiang Province of China under Grant No.LH2023A007the National Natural Science Foundation of China under Grant No.11201095+2 种基金the Fundamental Research Funds for the Central Universities under Grant Nos.3072022TS2402 and 3072024GH2402the Postdoctoral Research Startup Foundation of Heilongjiang under Grant No.LBH-Q14044the Science Research Funds for Overseas Returned Chinese Scholars of Heilongjiang Province under Grant No.LC201502.
文摘In this paper,the flocking behavior of a Cucker-Smale model with a leader and noise is studied in a finite time.The authors present a Cucker-Smale system with two nonlinear controls for a complex network with stochastic synchronization in probability.Based on the finite-time stability theory of stochastic differential equations,the sufficient conditions for the flocking of stochastic systems in a finite time are obtained by using the Lyapunov function method.Finally,the numerical simulation of the particle system is carried out for the leader and noise,and the correctness of the results is verified.
基金The first author is supported by NSFC(Grant No.12001530)。
文摘How to analyze flocking behaviors of a multi-agent system with local interaction functions is a challenging problem in theory.Motsch and Tadmor in 2011 also stressed the significance to assume that the interaction function is rapidly decaying or cut-off at a finite distance(cf.Motsch and Tadmor in J.Stat.Phys.2011).In this paper,we study the flocking behavior of a Cucker–Smale type model with compactly supported interaction functions.Using properties of a connected stochastic matrix,together with an elaborate analysis on perturbations of a linearized system,we obtain a sufficient condition imposed only on model parameters and initial data to guarantee flocking.Moreover,it is shown that the system achieves flocking at an exponential rate.
文摘Cucker-Smale系统中每个个体与其相邻个体的联系对其他个体产生有限的局部影响,最终实现全部个体状态一致。该系统被广泛应用于生态网络、控制理论、通信工程、模式识别和仿生学等领域。本文根据Cucker-Smale系统的控制研究现状,介绍了近期取得的理论成果,包括Cucker-Smale系统渐进和牵引蜂拥、带有噪声和时滞影响下的Cucker-Smale系统蜂拥、具有leader-follow关系的Cucker-Smale系统蜂拥。进一步详细介绍了牵引蜂拥及具有leader-follow关系的Cucker-Smale系统蜂拥控制的优点,同时给出下一步需要解决的具体问题。In the Cucker-Smale system, the interaction between each individual and its neighboring individuals exerts a limited local influence on other individuals, ultimately leading to consensus among all individuals. This system has been widely applied in various fields such as ecological networks, control theory, communication engineering, pattern recognition, and bionics. In this article, based on the current status of control research on the Cucker-Smale system, we introduce recent theoretical achievements, including asymptotic and pinning swarming of the Cucker-Smale system, swarming of the Cucker-Smale system with noise and time delay effects, and swarming of the Cucker-Smale system with leader-follow relationships. Further detailed introduction was given to the advantages of pinning swarming and the crowding control of the Cucker-Smale system with the leader-follow relationship while providing specific issues to be addressed in the next step.