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25th International Congress on Sound and Vibration 2018: Hiroshima Calling, ICSV 2018

作者： Feng, Jingjing Zhang, Wei Lui, Haiying Hu, Wenhua Beijing University of Technology College of Mechanical Engineering Beijing Key Laboratory on Nonlinear Vibrations and Strength of Mechanical Structures Beijing China Tianjin University of Technology School of Mechanical Engineering Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin China Tianjin University of Technology National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin China

ISBN: (纸本)9781510868458

The pull-in phenomenon is an important sign of instable movement for electrostatic micro-resonators. In present paper, the problems of homoclinic orbits and homoclinic bifurcation motion in a typical triple-well potential system with non-Z2 symmetric and higher-order nonlinear terms are studied, which is used to describe corresponding nonlinear dynamical behaviors of pull-in and complex vibration phenomena in typical micro-resonator. For the complexity between the equilibrium points and the phase space curves in triple-well potential system, the non-Z2 symmetric homoclinic orbits that are corresponding to the pull-in phenomenon are discussed under a certain energy input condition. Because the fact of the air damping in the actual micro-resonator cannot be ignored, the autonomous system containing the damping terms is studied directly. The further improved Padé approximation method can be applied to directly obtain analytical expressions of special homoclinic orbits with completely non-Z2 symmetry in corresponding conservative system, which contain not only the conventional Z2 symmetric nonlinear terms, but also the non-Z2 symmetric and higher-order nonlinear terms. In addition, the phase diagrams and bifurcation parameter curves of homoclinic orbit in corresponding autonomous system are obtained when the homoclinic bifurcation occurs. The present method is valid by comparing with the phase diagrams of homoclinic orbits from numerical method. Copyright © (2018) by International Institute of Acoustics & *** rights reserved.

关键词： Numerical methods

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Primary resonance analysis and optimal design of microbeam resonator with variable cross section under electrostatic actuator 25

Primary resonance analysis and optimal design of microbeam r...

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25th International Congress on Sound and Vibration 2018: Hiroshima Calling, ICSV 2018

作者： Liu, Cheng Hao, Shuying Zhang, Kunpeng Feng, Jingjing Zhang, Wei Tianjin University of Technology School of Mechanical Engineering Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin China Tianjin University of Technology National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin China Beijing University of Technology College of Mechanical Engineering Beijing Key Laboratory on Nonlinear Vibrations and Strength of Mechanical Structures Beijing China

ISBN: (纸本)9781510868458

In this paper, the doubly clamped microbeam-based resonator which actuated by two electrodes is investigated. A section parameter is proposed to describe the microbeam variables in the upper and under section. The differential equation is derived by considering the influence of neutral surface tension and the nonlinearity of electrostatic force. The Galerkin and Newton Cotes methods are used to obtain reduced-order model. The nonlinear vibration behaviors of system at equilibrium point are analysed. First, the frequency response is obtained by the method of multi-scale (MMS). The relationship between section parameter and mechanical property of the microresonator is studied. Then, the system is optimized by considering the relationship between section parameter and the actual physical parameters. Finally, the finite element method through COM-SOL software is used to verify the theoretical results, and the two results are very close to each other in the stable region. The research results provide a good reference for the design of microresonator. © 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling. All rights reserved.

关键词： Resonators

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Facile active control of a pulsed erbium-doped fiber laser using modulation depth tunable carbon nanotubes

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Photonics Research 2018年第11期6卷 996-1002页

作者： XINTONG XU SHUANGCHEN RUAN JIANPANG ZHAI LING LI JIHONG PEI ZIKANG TANG Shenzhen Key Laboratory of Laser Engineering Guangdong Provincial Key Laboratory of Micro/Nano Optomechatronics EngineeringShenzhen University College of Information Engineering ATR National Defence S&T Key Laboratory Shenzhen University Institute of Applied Physics & Materials Engineering Faculty of Science and Technology University of Macao

Short pulsed fiber lasers have been widely made using single-walled carbon nanotubes as a saturable absorber(SA). However, most of the currently used devices can only operate in one determined operation state with an unchangeable modulation SA depth in the cavity, which significantly limits their application in photonic *** this paper, well-aligned carbon nanotube arrays are synthesized using zeolite AlPO_4-5 as a template, which features anisotropic optical absorption. The linear optical absorption of the as-synthesized carbon nanotube arrays can easily be tuned by adjusting a polarization controller, thus providing a tunable modulation depth for the carbon nanotube SA. By exploiting this SA in an erbium-doped fiber laser cavity, both Q-switched and modelocked pulsed lasers are achieved by simply adjusting a polarization controller under a fixed pump power of 330 mW. In addition, the repetition rate of the Q-switching and pulse duration of the mode-locking can be tuned according to the variation of modulation depth. Moreover, soliton molecules can be obtained when the modulation depth of the SA is 4.5%.

关键词： SA SWCNTs carbon nanotubes

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Quantum tomography by regularized linear regression

arXiv

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arXiv 2019年

作者： Mu, Biqiang Qi, Hongsheng Petersen, Ian R. Shi, Guodong Key Laboratory of Systems and Control Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing100190 China Research School of Electrical Energy and Materials Engineering Australian National University Canberra0200 Australia Australian Center for Field Robotics School of Aerospace Mechanical and Mechatronic Engineering University of Sydney 2008 Australia

In this paper, we study extended linear regression approaches for quantum state tomography based on regularization techniques. For unknown quantum states represented by density matrices, performing measurements under certain basis yields random outcomes, from which a classical linear regression model can be established. First of all, for complete or over-complete measurement bases, we show that the empirical data can be utilized for the construction of a weighted least squares estimate (LSE) for quantum tomography. Taking into consideration the trace-one condition, a constrained weighted LSE can be explicitly computed, being the optimal unbiased estimation among all linear estimators. Next, for general measurement bases, we show that '2-regularization with proper regularization gain provides even lower mean-square error under a cost in bias. The regularization parameter is tuned by two estimators in terms of a risk characterization. Finally, a concise and unified formula is established for the regularization parameter with complete measurement basis under an equivalent regression model, which proves that the proposed tuning estimators are asymptotically optimal as the number of samples grows to infinity under the risk metric. Additionally, numerical examples are provided to validate the established results. Copyright © 2019, The Authors. All rights reserved.

关键词： Tomography

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Cooling Performance for Cylindrical Film-Cooling Hole with Divided Downstream Crescent-Shaped Block

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IOP Conference Series: Earth and Environmental science 2020年第1期461卷

作者： Pengfei Zhang Zhiting Tong Fei Wang Linchao Bai Chao Zhang Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology Tianjin 300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin 300384 China

The cooling performances for the cylindrical film-cooling hole with divided downstream crescent-shaped blocks were numerically investigated in present study. Four configurations with divided crescent-shaped block, i.e. linear, 30° convergence, 30° expansion, and 30° curved expansion, were studied at typical flow conditions. The successive crescent-shaped block case and the no block case were also solved in comparison. The temperature profiles, the local and lateral averaged cooling effectiveness at blowing ratios of 0.5 to 1.5 were obtained. As compared with the successive block case, the lateral coolant coverage were widened by using the divided block, and thus the lateral averaged cooling effectiveness were improved, especially at higher blowing ratios. Comparatively, the cylindrical hole with 30° expansion crescent-shaped block exhibited highest cooling performance.

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Measurement-induced boolean dynamics and controllability for quantum networks

arXiv

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arXiv 2019年

作者： Qi, Hongsheng Muy, Biqiang Petersenz, Ian R. Shix, Guodong Key Laboratory of Systems and Control Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing100190 China Research School of Electrical Energy and Materials Engineering Australian National University Canberra0200 Australia Australian Center for Field Robotics School of Aerospace Mechanical and Mechatronic Engineering University of Sydney NSW2008 Australia

In this paper, we study dynamical quantum networks which evolve according to Schrodinger equations but subject to sequential local or global quantum measurements. A network of qubits forms a composite quantum system whose state undergoes unitary evolution in between periodic measurements, leading to hybrid quantum dynamics with random jumps at discrete time instances along a continuous orbit. The measurements either act on the entire network of qubits, or only a subset of qubits. First of all, we reveal that this type of hybrid quantum dynamics induces probabilistic Boolean recursions representing the measurement outcomes. With global measurements, it is shown that such resulting Boolean recursions define Markov chains whose state-transitions are fully determined by the network Hamiltonian and the measurement observables. Particularly, we establish an explicit and algebraic representation of the underlying recursive random mapping driving such induced Markov chains. Next, with local measurements, the resulting probabilistic Boolean dynamics is shown to be no longer Markovian. The state transition probability at any given time becomes dependent on the entire history of the sample path, for which we establish a recursive way of computing such non-Markovian probability transitions. Finally, we adopt the classical bilinear control model for the continuous Schrodinger evolution, and show how the measurements affect the controllability of the quantum networks. Copyright © 2019, The Authors. All rights reserved.

关键词： Quantum optics

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Measurement-Induced boolean dynamics for open quantum networks

arXiv

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arXiv 2019年

作者： Qi, Hongsheng Mu, Biqiang Petersen, Ian R. Shi, Guodong Key Laboratory of Systems and Control Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing100190 China Research School of Electrical Energy and Materials Engineering Australian National University Canberra0200 Australia Australian Center for Field Robotics School of Aerospace Mechanical and Mechatronic Engineering University of Sydney NSW2008 Australia

In this paper, we study the recursion of measurement outcomes for open quantum networks under sequential measurements. Open quantum networks are networked quantum subsystems (e.g., qubits) with the state evolutions described by a continuous Lindblad master equation. When measurements are performed sequentially along such continuous dynamics, the quantum network states undergo random jumps and the corresponding measurement outcomes can be described by a vector of probabilistic Boolean variables. The induced recursion of the Boolean vectors forms a probabilistic Boolean network. First of all, we show that the state transition of the induced Boolean networks can be explicitly represented through realification of the master equation. Next, when the open quantum dynamics is relaxing in the sense that it possesses a unique equilibrium as a global attractor, structural properties including absorbing states, reducibility, and periodicity for the induced Boolean network are direct consequences of the relaxing property. Particularly, we show that generically, relaxing quantum dynamics leads to irreducible and aperiodic chains for the measurement outcomes. Finally, we show that for quantum consensus networks as a type of non-relaxing open quantum network dynamics, the communication classes of the measurement-induced Boolean networks are encoded in the quantum Laplacian of the underlying interaction graph. Copyright © 2019, The Authors. All rights reserved.

关键词： Quantum theory

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Behaviour of full grouted rock bolts subjected to repeated dynamic loading 3rd

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3rd International Conference on Rock Dynamics and Applications, ROCDYN-3 2018

作者： Wu, Q. Zhao, F. Zhou, Z.H. Li, Y. Zhang, S.P. Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Coal Mines Hunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines Hunan University of Science and Technology XiangtanHunan China School of Resources Environment and Safety Engineering Hunan University of Science and Technology XiangtanHunan China School of Mechatronic Engineering Hunan University of Science and Technology XiangtanHunan China

ISBN: (纸本)9780815396673

In order to investigate the effect of repeated dynamic loads on mechanical properties of the rock bolts. Based on the Split Hopkinson Pressure Bar (SHPB) system, a new device was introduced to study the effect of the dynamic load on rock bolts, including its layout and principle. The slippage of the rock bolt and the propagation of semi-sine stress waves in the bolt were investigated. The damage mechanisms of rock bolts under the dynamic loading were discussed briefly. The test results indicate that the failure of rock bolt is closely associated with the dynamic load. The anchorage zone has been damaged owing to the effect of the first dynamic load, and this damaged zone is further extended from the second dynamic load and rock squeezing, etc.), and it will be unable to resist the deformation of the surrounding rock. © 2018 Taylor & Francis Group, London.

关键词： Bolts

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Finite-time containment control of nonlinear multi-agent systems with non-singular terminal sliding mode

Finite-time containment control of nonlinear multi-agent sys...

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2018 Australian and New Zealand control Conference, ANZCC 2018

作者： Lu, Hui He, Wangli Han, Qing-Long Ge, Xiaohua Peng, Chen School of Mechatronic Engineering and Automation Shanghai University Shanghai200444 China Key Laboratory of Advanced Control and Optimization for Chemical Processes Ministry of Education East China University of Science and Technology Shanghai200237 China School of Software and Electrical Engineering Swinburne University of Technology MelbourneVIC3122 Australia

ISBN: (纸本)9781538666173

This paper is concerned with finite-time containment control problem for second-order nonlinear multi-agent systems with multiple dynamic leaders. Two new containment control protocols are developed to ensure that all followers converge to the dynamic convex hull spanned by the dynamic leaders in a finite time based on the terminal sliding mode and non-singular terminal sliding model, respectively. Moreover, the non-singular terminal sliding mode method is used to eliminate the singular problem associated with the terminal sliding mode control. Criteria on the existence of desired containment control protocols are also derived. Furthermore, the settling time is estimated under the proposed protocols. Simulation results illustrate the effectiveness of the developed theory in the last. © 2018 IEEE.

关键词： Multi agent systems

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Regional path moving horizon tracking controller design for autonomous ground vehicles

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science China(Information sciences) 2017年第1期60卷 201-207页

作者： Hongyan GUO Feng LIU Ru YU Zhenping SUN Hong CHEN State Key Laboratory of Automotive Simulation and Control Jilin University(Campus Nanling) College of Communication Engineering Jilin University (Campus Nanling) School of Mechatronic Engineering and Automation National University of Defense Technology

A novel regional path tracking description is presented in this manuscript, and the moving horizon control method that is model predictive control(MPC) is proposed to discuss the regional path tracking issue which could avoid colliding road boundary when tracking a more complex road effectively. The feasible region for autonomous ground vehicles(AGVs) running is determined first according to the detected road ***, in order to keep the actual trajectory of AGVs in the region and satisfy the safety requirements, MPC method is employed to design the path tracking controller considering actuator and road boundary *** order to verify the effectiveness of the proposed method, experiments based on Hongqi AGV HQ430 are carried out, and the results illustrate that the presented method could be successfully applied to Hongqi AGV vehicle HQ 430.

关键词： autonomous ground vehicles regional path tracking model predictive control road boundaries experimental validation

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