Active structural control for load mitigation of wind turbines via adaptive sliding-mode approach     

Yinlong Hu  Michael Z.Q. Chen  Chanying Li 《Journal of The Franklin Institute》2017,354(11):4311-4330

This paper studies the load mitigation problem for wind turbines by using active tuned mass dampers. A state space model for the tower/nacelle system is established with the consideration of tower/blade interaction. The uncertainties that appear in the damping matrix and natural frequencies are also considered in the controller design. External loads acting on the tower including the drag force induced by winds and the absolute base shear induced by the rotating blades are involved, and shaping filters for online generating these loads are proposed which can be easily implemented in numerical simulations. An adaptive sliding-mode controller is proposed to handle the system uncertainties, external disturbances and hard constraint, and also to improve the overall performance of the wind turbine system. Numerical simulations are performed to demonstrate the effectiveness of the proposed control law.  相似文献   

Finite-time multi-switching synchronization behavior for multiple chaotic systems with network transmission mode     

Xiangyong Chen  Jinde Cao  Ju H. Park  Tingwen Huang  Jianlong Qiu 《Journal of The Franklin Institute》2018,355(5):2892-2911

By considering network transmission mode, this paper addresses the finite-time multi-switching synchronization problem for two kinds of multiple chaotic systems. For multiple same-order chaotic systems, we construct the general switching rules and analyze the existence of switching cases. The presented schemes guarantee the states of each derive system to be finite-timely synchronized with the desired states of every respond system in the different transmission paths and switching sequences. For multiple different order chaotic systems, we analyze a special multi-switching hybrid synchronization behavior, where part of the states are completely synchronized and the others belong to combination synchronization. Moveover, the easily verifiable criterion is derived for such synchronization. Finally, numerical examples are given to show the effectiveness of the presented theoretical results.  相似文献   

A new excitation scheme for closed-loop subspace identification using additional sampling outputs and its extension to instrumental variable method     

Kai Wang  Junghui Chen  Zhihuan Song 《Journal of The Franklin Institute》2018,355(14):6675-6692

It is known that feedback from outputs to inputs causes non-identifiability in many subspace identification algorithms. In this paper, a new excitation method is proposed for closed-loop subspace identification. By adding an output sampling point within two adjacent control times, a difficult closed loop identification issue is recast into an open loop identification. Uncorrelation between the process inputs and the noises in closed loop is obtained, and the persistently exciting condition is proven to be satisfied based on spectral analysis and innovation state space models so that the consistent estimates with no demand for external exciting signals can be guaranteed. Simultaneously, the additional sampling scheme offers different selections of instrumental variables for the non-error-in-variable case and the error-in-variable case in some instrumental variables-based identification algorithms. A simulation is performed to test the identification efficiency of the new scheme.  相似文献   

A Katz-centrality-based protocol design for leader-following formation of discrete-time multi-agent systems with communication delays     

M.J. Park  O.M. Kwon  J.H. Ryu 《Journal of The Franklin Institute》2018,355(13):6111-6131

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《武警医学》作者学术不端认知与行为调查分析     

李小萍  武建虎  尤伟杰 《编辑学报》2013,25(1):57-59

为了解医学期刊作者对学术不端的认知及其行为情况,以为更好地防止学术不端提供一些思路和方法,以近2年在《武警医学》发表过文章的作者作为调查对象.调查结果表明:多数作者对学术不端的认识不全面,部分科室学术不端情况比较严重;但多数作者希望共同抵制学术不端行为.  相似文献