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Formation of Vortices in a Three-dimensional Dipolar Bose-Einstein Condensate
Yuan Sheng Wang,Shen Tong Ji,Yue E Luo,Zhen Yu Li 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.9
We investigate the vortex formation properties of a three-dimensional (3D) dipolar Bose-Einstein condensate (BEC) of 52Cr atoms in an optical lattice potential through numerical simulations of the time-dependent Gross-Pitaevskii equation with a dissipation term. The mechanisms that influence the dipole-dipole interaction and the repulsive contact interaction between atoms during vortex formation are analyzed. We find that the stability of the vortices weakens with increasing attractive dipolar strength and that the repulsive contact interaction between atoms can increase the number of vortices.
Tracking Control for a Quadrotor via Dynamic Surface Control and Adaptive Dynamic Programming
Qiang Gao,Xin-Tong Wei,Da-Hua Li,Yue-Hui Ji,Chao Jia 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.1
In this paper, a data-driven control algorithm based on the Dynamic Surface Control and the ActionDependent Heuristic Dynamic Programming is proposed to realize the stable tracking control of the quadrotor. Firstly, the dynamic surface control is addressed for the nonlinear model of the quadrotor, which can overcome the “explosion of complexity” problem encountered in traditional back-stepping method inevitably. The controller designed by Dynamic Surface Control is served as the main controller in the total control structure. Secondly, the Action-Dependent Heuristic Dynamic Programming is investigated to construct a complementary attitude controller by involving the learning mechanism. The adoption of Action-Dependent Heuristic Dynamic Programming can provide the capability of adaptation and disturbance rejection to improve the tracking control performance effectively. The overall closed-loop system is proved to be asymptotically stable by the Lyapunov theorem. Finally, the numerical simulation and flight experiments are presented to demonstrate that the proposed tracking control scheme exhibits an excellent tracking performance in the case of external disturbances.