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Zhou Y.,Beijing Jiaotong University | Zhang Z.,Beijing Jiaotong University | Zhang Z.,Taiyuan Satellite Launch Center
Vehicle System Dynamics

Speed uplift has become the leading trend for the development of current railway traffic. Ideally, under the high-speed transportation infrastructure, trains run at specified positions with designated speeds at appointed times. In view of the faster adaptation ability of multiple-model adaptive control with second-level adaptation (MMAC-SLA), we propose one type of MMAC-SLA for a class of nonlinear systems such as cascaded vehicles. By using an input decomposition technique, the corresponding stability proof is solved for the proposed MMAC-SLA, which synthesises the control signals from the weighted multiple models. The control strategy is utilised to challenge the position and speed tracking of high-speed trains with uncertain parameters. The simulation results demonstrate that the proposed MMAC-SLA can achieve small tracking errors with moderate in-train forces incurred under the control of flattening input signals with practical enforceability. This study also provides a new idea for the control of in-train forces by tracking the positions and speeds of cars while considering power constraints. © 2013 Taylor & Francis. Source

A matrix inequality approach is proposed for local stabilization of a class of uncertain linear systems subject to time-varying input delays, actuator saturation, and norm-bounded disturbances. Delay-dependent stability and stabilization conditions by using the linear state-feedback control law are obtained to guarantee the uniform boundedness of solutions of the closed-loop systems. Besides, an admissible maximum bound of disturbances can be ascertained to ensure the existence of a non-empty set of initial conditions. An optimization framework is formulated further for the maximization purpose of the admissible upper bound of disturbances and the size of the set of initial conditions. A numerical example is provided to demonstrate the effectiveness of proposed design techniques. © 2015 Technical Committee on Control Theory, Chinese Association of Automation. Source

Song S.,National University of Defense Technology | Song S.,China Aerodynamics Research And Development Center | Wan M.,Nanyang Technological University | Wang S.,Taiyuan Satellite Launch Center | And 2 more authors.
Communications in Computational Physics

A novel method for boundary constrained tetrahedral mesh generation is proposed based on Advancing Front Technique (AFT) and conforming Delaunay triangulation. Given a triangulated surface mesh, AFT is firstly applied to mesh several layers of elements adjacent to the boundary. The rest of the domain is then meshed by the conforming Delaunay triangulation. The non-conformal interface between two parts of meshes are adjusted. Mesh refinement and mesh optimization are then preformed to obtain a more reasonable-sized mesh with better quality. Robustness and quality of the proposed method is shown. Convergence proof of each stage as well as the whole algorithm is provided. Various numerical examples are included as well as the quality of the meshes. © 2013 Global-Science Press. Source

Feng F.,Academy of Armored force Engineering | Si A.,Academy of Armored force Engineering | Zhang H.,Taiyuan Satellite Launch Center
Procedia Engineering

Aimed at the problem of the feature of nonstationary vibration signal can not be extracted easily; the bispectrum analysis technique was researched in this paper. Bispectral characteristic frequency faces were searched along the parallel to the diagonal line at certain step in the bispectral modulus field, and the mean magnitude was calculated to get the feature parameters. The method was applied in fault feature extraction of piston-pin of diesel engine successfully. Finally, the piston-pin faults were diagnosed associated with genetic neural network. © 2011 Published by Elsevier Ltd. Source

Yang Y.,Academy of Armored force Engineering | Jiang P.,Academy of Armored force Engineering | Cong H.,Academy of Armored force Engineering | Feng F.,Academy of Armored force Engineering | Zhang H.,Taiyuan Satellite Launch Center
Applied Thermal Engineering

Abstract The existing control methods for Air handling units (AHUs) in spacecraft launching site (SLS) are comparatively dated, the air processing routes are usually arbitrarily determined in line with experience, which fails to cope with the coupling and function redundancy of air condition system and the diversity of outdoor environment, therefore resulting in tremendous energy waste. This paper proposes a new route optimization strategy for fresh air processing - Firstly analyzing the possibly processing routes for fresh air based on psychrometric chart, then proposing an optimization algorithm AFSA-GA to optimize the possibly processing routes, eventually obtaining the best route that requires the least energy consumption. By adopting the strategy proposed to optimize air processing route for High-Temperature and High-Humidity working conditions, it can be proved that the proposed strategy can decrease considerable amount of energy consumption, and the proposed optimization algorithm AFSA-GA has the advantages of faster convergence speed and avoiding premature. © 2015 Elsevier Ltd. Source

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