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Science China(Information Sciences) 2017年第11期60卷 265-267页

作者： Shuang HU jihong zhu Department of Computer Science and Technology Tsinghua University

The extension of flight envelope to high angles of attack has been a key requirement for modern *** combat aircrafts should be provided with super maneuver performance to improve operational *** this case,the incidence of aircraft could be very large,even reaching post stall *** aerodynamics show strong nonlinear and unsteady characteristics in the flight of high incidence,which are caused by complex flow structures such as attached flow separation and vortex burst[1].The unsteady aerodynamic modeling at high incidences is helpful to control law design and flight simulation which has great practical *** its progress over two decades,unsteady aerodynamic models can

关键词： wind tunnel operational effectiveness flow separation flight envelope complex flow

Hover control of a thrust-vectoring aircraft

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Science China(Information Sciences) 2015年第7期58卷 200-204页

作者： KUANG MinChi zhu jihong Department of Computer Science and Technology Tsinghua University

In this paper, the hover control method of a thrust-vectoring aircraft is discussed, which is the first step to realize vertical takeoff and landing(VTOL) as a tail-sitter. To avoid the gimbal lock problem,vertical Euler angles are used and a new calculation method of them is presented. The attitude controller switches between horizon mode and vertical mode, with a specially designed switchable control ***/constant acceleration approximation is used for attitude control, which aims to get quick response and prevent overshooting at the same time. Special proportion integral derivative(PID) controller with anti-torque counteraction is proposed to generate servo angles. Experimental results verify the effectiveness of the proposed control method.

关键词： hover control thrust-vectoring aircraft tail-sitter vertical takeoff and landing(VTOL) vertical Euler angles

A Reinforcement Learning System for Fault Detection and Diagnosis in Mechatronic Systems

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Computer Modeling in Engineering & Sciences 2020年第9期124卷 1119-1130页

作者： Wanxin Zhang jihong zhu School of Electronics and Information Technology Sun Yat-sen UniversityGuangzhou510006China Department of Computer Science and Technology Tsinghua UniversityBeijing100084China

With the increasing demand for the automation of operations and processes in mechatronic systems,fault detection and diagnosis has become a major topic to guarantee the process *** exist numerous studies on the topic of applying artificial intelligence methods for fault detection and ***,much of the focus has been given on the detection of *** terms of the diagnosis of faults,on one hand,assumptions are required,which restricts the diagnosis *** the other hand,different faults with similar symptoms cannot be distinguished,especially when the model is not trained by plenty of *** this work,we proposed a reinforcement learning system for fault detection and *** assumption is *** exaction is first *** with the features as the states of the environment,the agent directly interacts with the *** policy,which determines the exact category,size and location of the fault,is obtained by updating Q *** method takes advantage of expert *** the features are unclear,action will be made to get more information from the new state for further *** create recurrent neural network with the long short-term memory architecture to approximate Q *** application on a motor is *** experimental results validate that the proposed method demonstrates a significant improvement compared with existing state-of-the-art methods of fault detection and diagnosis.

关键词： Classification reinforcement learning neural network feature exaction and selection fault detection and diagnosis

Composite dynamic surface control of hypersonic flight dynamics using neural networks

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Science China(Information Sciences) 2015年第7期58卷 40-48页

作者： ZHANG ShangMin LI ChunWen zhu jihong Department of Automation Tsinghua University Department of Computer Science and Technology Tsinghua University

This paper addresses the composite neural tracking control for the longitudinal dynamics of hypersonic flight dynamics. The dynamics is decoupled into velocity subsystem, altitude subsystem, and attitude subsystem. For the altitude subsystem, the reference command of flight path angle is derived for the attitude subsystem. To deal with the system uncertainty and provide efficient neural learning, the composite law for neural weights updating is studied with both tracking error and modeling error. The uniformly ultimate boundedness stability is guaranteed via Lyapunov approach. Under the dynamic surface control with novel neural design, the neural system converges in a faster mode and better tracking performance is obtained. Simulation results are presented to show the effectiveness of the design.

关键词： hypersonic flight vehicle composite dynamic surface control neural network longitudinal dynam-ics stability

Thrust vectoring control of vertical/short takeoff and landing aircraft

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Science China(Information Sciences) 2020年第2期63卷 218-220页

作者： Xiangyang WANG Bin zhu jihong zhu Zhiqiang CHENG Department of Computer Science and Technology Tsinghua University Automation Academy Nanjing University of Science and Technology

Thrust-vectored vertical and/or short take-off and landing (V/STOL) aircraft use a vertical lift fan and a 3-bearing swivel duct (3BSD) nozzle to deliver vertical takeoff, landing and short takeoff capability. The ban... 详细信息

关键词： BSD Thrust vectoring control of vertical/short takeoff and landing aircraft

Design of nanofluid-cooled heat sink using topology optimization

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Chinese Journal of Aeronautics 2021年第2期34卷 301-317页

作者： Bin ZHANG jihong zhu Gaoxiang XIANG Limin GAO Deparment of Engineering Mechanics School of MechanicsCivil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China MIIT Lab of Metal Addive Manufacturing and Innovative Design Northwvestern Polytechrical UniversilyXi'an 710072China School of Power and Energy Northwestern Polytechnical UniversityXi'an 710072China

The paper presented topology optimization of 2 D and 3 D Nanofluid-Cooled Heat Sink(NCHS). The flow and heat transfer problem in the NCHS was treated as a single-phase nanofluid based convective heat transfer model. The temperature-dependent fluid properties were taken into account in the model due to the strong temperature-dependent features of nanofluids. An average temperature minimum problem was studied subject to the fluid area and energy dissipation constraints by using the density method. In the method, the design variable is updated according to the gradient information obtained by an adjoint based sensitivity analysis process. The effects of the energy dissipation constraint, temperature-dependent fluid properties and nanofluid characteristics on optimal configurations of NCHS were numerically investigated with following ***, branched flow channels in the optimal configuration increased with the rise of the allowed energy dissipation. Secondly, temperature-dependent fluid properties were significant for obtaining the appropriate optimal results with best cooling performance. Thirdly, heat transfer performances of optimal configurations were enhanced by reducing the nanoparticle diameter or increasing the nanoparticle volume fraction. Fourthly, the optimal configuration for nanofluid had better cooling performance than that for its base fluid.

关键词： Forced convection Heat sinks Heat transfer Nanofluid Sensitivity analysis Topology optimization

Precise output loads control of load-diffusion components with topology optimization

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Chinese Journal of Aeronautics 2020年第3期33卷 933-946页

作者： Yinfeng CAO Xiaojun GU jihong zhu Weihong ZHANG State IJR Center of Aerospace Design and Additive Manufacturing Northwestern Polytechnical UniversityXi’an 710072China Institute of Intelligence Material and Structure Unmanned System TechnologiesNorthwestern Polytechnical UniversityXi’an 710072China MIIT Lab of Metal Additive Manufacturing and Innovative Design Northwestern Polytechnical UniversityXi’an 710072China

The purpose of this paper is to present a novel topology optimization approach to control precisely the output loads under static loads and harmonic *** introduce the Artificial Bar Element(ABE)at the designated output positions,where the output loads are equivalently measured and constrained with the nodal displacements of *** model is then formulated considering the output load constraints as well as the minimization of strain energy and dynamic displacement responses respectively under the static and dynamic *** influences of the ABEs stiffness,different material usages of the design domain,widths of the output loads constraint intervals and variation ratios of output loads are discussed in *** proposed method is verified with several numerical examples with clear and reasonable load transfer paths.

关键词： Artificial bar elements Dynamic response Kreisselmeier-Steinhauser(KS)function Precise control of output loads Topology optimization

Optimization design of chiral hexagonal honeycombs with prescribed elastic properties under large deformation

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Chinese Journal of Aeronautics 2020年第3期33卷 902-909页

作者： Kepeng QIU Ruoyao WANG jihong zhu Weihong ZHANG School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China

Flexible chiral honeycomb cores generally exhibit nonlinear elastic properties due to large geometric *** effective elastic moduli and Poisson's ratio typically vary with an increase in ***,the size and shape optimization of the chiral hexagonal honeycombs was performed to keep the Young's moduli and Poisson's ratio unchanged under large *** size of the honeycomb unit cell and the position coordinates of the key points were defined simultaneously as design *** equivalent Young's modulus and Poisson's ratio of chiral honeycombs were calculated through geometric nonlinear *** objective was to minimize the allowable tolerance between the prescribed and actual properties within the range of the target strain.A genetic algorithm was then *** optimal results demonstrate that the chiral honeycombs can maintain effective elastic properties that do not vary under large *** results are meaningful to morphing aircraft designs.

关键词： Chiral hexagonal honeycombs Genetic algorithm Geometric nonlinearity Large deformation Shape optimization

Multiscale topology optimization using feature-driven method

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Chinese Journal of Aeronautics 2020年第2期33卷 621-633页

作者： Zhao XU Weihong ZHANG Ying ZHOU jihong zhu State IJR Center of Aerospace Design and Additive Manufacturing Northwestern Polytechnical UniversityXi’an 710072China

This paper presents a multiscale design method for simultaneous topology optimization of both macrostructures and *** features are extended as design primitives at both macro and micro scales and represented by Level Set Functions(LSFs).Parameters related to the locations,sizes,and orientations of macro and micro features are considered as design variables and optimized *** the overlapping areas of different macro features,embedded microstructures are optimally figured out as the solution of the corresponding sub-optimization,*** this study,the eXtended Finite Element Method(XFEM)is implemented for structural and sensitivity analyses with respect to design *** method has the advantage of using a fixed grid independent of the topology optimization *** homogenization procedure is applied to calculate the effective properties of considered microstructures in each macro *** examples are presented to illustrate the effectiveness of the proposed *** depict that the multiscale design cannot obviously improve structural stiffness compared with a solid-material design under the linear elastic condition.

关键词： Feature-driven method Level set function Multiscale design Topology optimization XFEM

Structural topology optimization under stationary random base acceleration excitations

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Chinese Journal of Aeronautics 2019年第6期32卷 1416-1427页

作者： Fei HE Hongqiang LIAO jihong zhu Zhongze GUO Institute of Systems Engineering China Academy of Engineering PhysicsMianyang 621900China State IJR Center of Aerospace Design and Additive Manufacturing Northwestern Polytechnical UniversityXi’an 710072China

Structural topology optimization subjected to stationary random base acceleration excitations is investigated in this paper. In the random response analysis, the Large Mass Method(LMM) which attributes artificial large mass values at each driven nodal Degree Of Freedom(DOF) to transforming the base acceleration excitations into force excitations is proposed. The Complete Quadratic Combination(CQC) which is commonly used to calculate the random responses in previous optimization has been proven to be computationally expensive especially for large-scale problems. In order to conquer this difficulty, the Pseudo Excitation Method(PEM) and the combined method of PEM and Mode Acceleration Method(MAM) are adopted into the dynamic topology optimization, and random responses are calculated using these two methods to ascertain a high efficiency over the CQC. A density-based topology optimization method minimizing dynamic responses is then formulated based on the integration of LMM and PEM or the combined method of PEM and MAM. Numerical examples are presented to verify the accuracy of the proposed schemes in dynamic response analysis and the quality of the optimized design in improving dynamic performance.

关键词： Dynamic response Large mass method Mode acceleration method Pseudo excitation method Random base acceleration excitations Topology optimization