scholarly journals Effects of Cavity on the Performance of Dual Throat Nozzle During the Thrust-Vectoring Starting Transient Process

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Rui Gu ◽  
Jinglei Xu
Keyword(s):  
Numerical Simulations ◽  
Transient Process ◽  
Dynamic Loads ◽  
Challenging Problem ◽  
Excellent Performance ◽  
Thrust Vectoring ◽  
Process Dynamic ◽  
Parameter Variations ◽  
Starting Process ◽  
And Control

The dual throat nozzle (DTN) technique is capable to achieve higher thrust-vectoring efficiencies than other fluidic techniques, without compromising thrust efficiency significantly during vectoring operation. The excellent performance of the DTN is mainly due to the concaved cavity. In this paper, two DTNs of different scales have been investigated by unsteady numerical simulations to compare the parameter variations and study the effects of cavity during the vector starting process. The results remind us that during the vector starting process, dynamic loads may be generated, which is a potentially challenging problem for the aircraft trim and control.

scholarly journals Chaos and Control in Coronary Artery System

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Yanxiang Shi
Keyword(s):  
Coronary Artery ◽  
Feedback Control ◽  
Numerical Simulations ◽  
Melnikov Method ◽  
Phase Portraits ◽  
Bifurcation Diagrams ◽  
Nonlinear Dynamical ◽  
The Road ◽  
Two Systems ◽  
And Control

Two types of coronary artery system N-type and S-type, are investigated. The threshold conditions for the occurrence of Smale horseshoe chaos are obtained by using Melnikov method. Numerical simulations including phase portraits, potential diagram, homoclinic bifurcation curve diagrams, bifurcation diagrams, and Poincaré maps not only prove the correctness of theoretical analysis but also show the interesting bifurcation diagrams and the more new complex dynamical behaviors. Numerical simulations are used to investigate the nonlinear dynamical characteristics and complexity of the two systems, revealing bifurcation forms and the road leading to chaotic motion. Finally the chaotic states of the two systems are effectively controlled by two control methods: variable feedback control and coupled feedback control.

scholarly journals Online Estimation and Control for Feed Drive Systems With Unmeasurable Parameter Variations

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 33966-33976 ◽  
Author(s):  
Tiancheng Zhong ◽  
Ryozo Nagamune ◽  
Alexander Yuen ◽  
Wencheng Tang
Keyword(s):  
Online Estimation ◽  
Feed Drive ◽  
Parameter Variations ◽  
Estimation And Control ◽  
Drive Systems ◽  
And Control

ESTIMATION OF CONTROL ENERGY AND CONTROL STRATEGIES FOR COMPLEX NETWORKS

2015 ◽  
Vol 18 (07n08) ◽  
pp. 1550018 ◽  
Author(s):  
DINGJIE WANG ◽  
SUOQIN JIN ◽  
FANG-XIANG WU ◽  
XIUFEN ZOU
Keyword(s):  
Complex Networks ◽  
Numerical Simulations ◽  
Energy Cost ◽  
Control Strategies ◽  
Energy Costs ◽  
Theoretical Derivation ◽  
Complete Control ◽  
Undirected Network ◽  
Normal Networks ◽  
And Control

The controlling of complex networks is one of the most challenging problems in modern network science. Accordingly, the required energy cost of control is a fundamental and significant problem. In this paper, we present the theoretical analysis and numerical simulations to study the controllability of complex networks from the energy perspective. First, by combining theoretical derivation and numerical simulations, we obtain lower bounds of the maximal and minimal energy costs for an arbitrary normal network, which are related to the eigenvalues of the state transition matrix. Second, we deduce that controlling unstable normal networks is easier than controlling stable normal networks with the same size. Third, we demonstrate a tradeoff between the control energy and the average degree (or the maximum degree) of an arbitrary undirected network. Fourth, numerical simulations show that the energy cost is negatively correlated with the degree of nodes. Moreover, the combinations of control nodes with the greater sum of degree need less energy to implement complete control. Finally, we propose a multi-objective optimization model to obtain the control strategy, which not only ensures the fewer control nodes but also guarantees the less energy cost of control.

Modeling and Identification of a Large-Scale Magnetorheological Fluid Damper

2008 ◽  
Vol 56 ◽  
pp. 374-379
Author(s):  
Arturo Rodriguez ◽  
N. Iwata ◽  
Fayçal Ikhouane ◽  
José Rodellar
Keyword(s):  
Large Scale ◽  
Dynamic Loads ◽  
Control System Design ◽  
Mr Dampers ◽  
Highly Nonlinear ◽  
Fluid Damper ◽  
Control Devices ◽  
Simulation And Control ◽  
Mr Fluid Damper ◽  
And Control

In the last years there has been an increasing interest to magnetorheological (MR) dampers and their applications to civil engineering. In particular they have been used as semi-active control devices for vibration mitigation due to external dynamic loads. These devices are highly nonlinear and thus accurate models of these devices are important for effective simulation and control system design. Two hysteretic models based on the normalized Bouc-Wen model are proposed in this paper to compare their effectiveness in a large scale MR fluid damper. A methodology for identification is proposed, and the obtained models are tested and validated experimentally.

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