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Trajectory generation of heat load test based on gauss pseudospectral method

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science china(Technological sciences) 2018年第2期61卷 273-284页

作者： ZHANG YuanLong LIU LuHua TANG GuoJian BAO WeiMin College of aerospace science and Engineering National University of Defense TechnologyChangsha 410073China china aerospace science and technology corporation Beijing 100048China

A new trajectory generation for heat load test is proposed based on gauss pseudospectral method within limit range. Firstly,with multiple path constraints and flight task requirements taken into consideration, heat load parameters are introduced into the dynamics equations. In order to solve the problem of generating such a trajectory within limit range rapidly, the dynamics equations have been normalized by Earth related parameters. Secondly, since the gauss pseudospectral method is just employed to solve the discrete nonlinear programming problem, transformations are developed, which can relate the Lagrange multipliers of the discrete nonlinear programming problem to the costates of the continuous optimal control problem. In addtion, another approach of trajectory generation by tracking the given heat rate is also presented. Finally, simulation results with common aero vehicle(CAV-H) show that the trajectories obtained by both methods can well perform the heat load test with high stagnation heating rate and the large total aeroheating amount; meanwhile, gauss pseudospectral method is better than the compared one in the given range. Furthermore, the 3-D trajectory states and control variables, angle of attack and bank, which are generated by gauss pseudospectral method, can change smoothly.

关键词： glide vehicle trajectory generation heat load test gauss pseudospectral method

Extended differential geometric guidance law for intercepting maneuvering targets

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Journal of Systems Engineering and Electronics 2018年第5期29卷 1046-1057页

作者： HUANG Jingshuai ZHANG Hongbo TANG Guojian BAO Weimin College of aerospace science and Engineering National University of Defense TechnologyChangsha 410073China china aerospace science and technology corporation Beijing 100048China

Without assumptions made on motion states of missile and target, an extended differential geometric guidance law is derived. Through introducing a line of sight rotation coordinate system, the derivation is simplified and has more explicit physical significances. The extended law is theoretically applicable to any engagement scenarios. Then, on basis of the extended law, a modified one is designed without the requirement of target acceleration and an approach is proposed to determining the applied direction of commanded missile acceleration. Qualitative analysis is carried out to study the capture performance and a criterion for capture is given. Simulation results indicate the two laws are effective and make up the deficiency that pure proportional navigation suitable for endoatmospheric interceptions cannot deal with high-speed maneuvering targets. Furthermore, the correctness of the criterion is validated.

关键词： missile guidance maneuvering target extended differential geometric guidance law capture performance proportional navigation

Semi-Autonomous Navigation Based on Local Semantic Map for Mobile Robot

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Journal of Shanghai Jiaotong university(science) 2025年第1期30卷 27-33页

作者： ZHAO Yanfei XIAO Peng WANG Jingchuan GUO Rui Department of Automation Institute of Medical RoboticsShanghai Jiao Tong UniversityShanghai200240China State Key Laboratory of System Control and Information Processing Ministry of Education of ChinaShanghai200240China Shanghai Engineering Research Center of Intelligent Control and Management Shanghai200240China State Grid Intelligence technology Co. Ltd.Jinan250013China

Mobile robots represented by smart wheelchairs can assist elderly people with mobility *** paper proposes a multi-mode semi-autonomous navigation system based on a local semantic map for mobile robots,which can assist users to implement accurate navigation(e.g.,docking)in the environment without prior *** order to overcome the problem of repeated oscillations during the docking of traditional local path planning algorithms,this paper adopts a mode-switching method and uses feedback control to perform docking when approaching semantic *** last,comparative experiments were carried out in the real *** show that our method is superior in terms of safety,comfort and docking accuracy.

关键词： semi-autonomous navigation mobile robot semantic map voice interaction

Effect of heat treatment on microstructure and mechanical properties of a novel Al-Zn-Mg-Cu alloy

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china Foundry 2025年

作者： Yan-mei Yang Xin-chen Tang Ye-fei Li Xue-wei Fang Da-wei Yi Zhi-yun Zhang Qiao-ling Zheng Zhi-xi Wang Guo-yu Zhang Su Zhang Hao Cheng Yang He Yi-bo Liu Zi-han Wu Ya-nan Chen Yi-min Gao State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University Xi'an aerospace Precision Electromechanical institute

Effects of solution and aging treatment on the microstructure and mechanical properties of a novel Al-Zn-Mg-Cu alloy by microalloying rare elements Sc and Er were studied. The results show that solution time has a visible influence on the microstructure and mechanical properties of the alloy. Specifically, as the solution time increases, the area fraction of the residual phase in the alloy decreases, and the shape of the grain becomes more spheroidal and coarser, leading to a decrease in hardness. This is attributed to the dissolution of strengthening phases during the solution treatment, which weakens the solid solution strengthening *** single-stage aging treatment shows an initial increase in strength and hardness of the alloy, followed by a decrease as the aging time is extended, until a steady state is achieved. The optimal single-aging conditions are found to be at 120 ℃ for 24 h, where the alloy exhibits an excellent combination of high strength and good ductility, with an ultimate tensile strength(UTS) of 523 MPa, yield strength(YS) of 482 MPa, and elongation(El)of 1.75%, respectively. Compared to single-stage aging, double-stage aging(120 ℃ for 24 h and then 150 ℃ for 52 h) significantly increases the elongation of the alloy(4.17%), but the UTS reduces to 465.29 MPa, and YS reduces to 410.64 MPa. Transmission electron microscopy(TEM) observations disclose that the grain size, the distribution spacing of precipitates along the grain boundary, and the width of the precipitation-free zone(PFZ) all undergo augmentation as the duration of the second stage aging process elongates.

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Uncertainty analysis and design optimization of hybrid rocket motor powered vehicle for suborbital flight

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Chinese Journal of Aeronautics 2015年第3期28卷 676-686页

作者： Zhu Hao Tian Hui Cai Guobiao Bao Weimin School of Astronautics Beihang University china aerospace science and technology corporation

Abstract In this paper, we propose an uncertainty analysis and design optimization method and its applications on a hybrid rocket motor （HRM） powered vehicle. The multidisciplinary design model of the rocket system is established and the design uncertainties are quantified. The sensitivity anal- ysis of the uncertainties shows that the uncertainty generated from the error of fuel regression rate model has the most significant effect on the system performances. Then the differences between deterministic design optimization （DDO） and uncertainty-based design optimization （UDO） are discussed. Two newly formed uncertainty analysis methods, including the Kriging-based Monte Carlo simulation （KMCS） and Kriging-based Taylor series approximation （KTSA）, are carried out using a global approximation Kriging modeling method. Based on the system design model and the results of design uncertainty analysis, the design optimization of an HRM powered vehicle for suborbital flight is implemented using three design optimization methods： DDO, KMCS and KTSA. The comparisons indicate that the two UDO methods can enhance the design reliability and robustness. The researches and methods proposed in this paper can provide a better way for the general design of HRM powered vehicles.

关键词： Design optimization Hybrid rocket motor Kriging model Uncertainty analysis Uncertainty-based designoptimization

Three-dimensional nonlinear coupling guidance for hypersonic vehicle in dive phase

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science china(Technological sciences) 2014年第9期57卷 1824-1833页

作者： ZHU JianWen LIU LuHua TANG GuoJian BAO WeiMin College of aerospace science and Engineering National University of Defense Technology china aerospace science and technology corporation

Three-dimensional(3D)nonlinear diving guidance strategy considering the coupling between longitudinal and lateral motions for hypersonic vehicle is investigated in this *** constructs the complete nonlinear coupling motion equation without any approximations based on diving relative motion relationship directly,and converts it into linear state space equation with the same relative degree by feedback *** the linear equation,slide mode control with strong robustness is employed to design the guidance law,and 3D diving guidance law which can satisfy terminal impact point and falling angle constraints with high precision is obtained by substituting the previous control law into the origin nonlinear guidance ***,regarding lateral overload as the standard,hybrid control strategy which can take full advantage of the excellent characters of both bank-to-turn(BTT)and skid-to-turn(STT)controls is designed to improve the guidance accuracy ***,the results of CAV-H vehicle guidance test show that the algorithm can realize high accuracy guidance even if serious motion coupling exists,and has strong robustness to the path disturbances and navigation errors as well.

关键词： hypersonic vehicle 3D diving guidance coupling feedback linearization slide mode control hybrid control strategy

Uncertainty analysis and probabilistic design optimization of hybrid rocket motors for manned lunar landing

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science china(Technological sciences) 2015年第7期58卷 1234-1241页

作者： ZHU Hao TIAN Hui CAI GuoBiao BAO WeiMin School of Astronautics Beihang University china aerospace science and technology corporation

To obtain a conceptual design for a hybrid rocket motor(HRM)to be used as the Ascent Propulsion System in the Apollo lunar module,the deterministic design optimization(DDO)method is applied to the HRM *** on the results of an uncertainty analysis of HRMs,an uncertainty-based design optimization(UDO)method is also adopted to improve the design *** HRM design process,which is a multidisciplinary system,is analyzed,and a mathematical model for the system design is established to compute the motor performance from the input parameters,including the input variables and model *** input parameter uncertainties are quantified,and a sensitivity analysis of the model parameter uncertainties is conducted to identify the most important model parameter uncertainties for *** DDO and probabilistic UDO methods are applied to conceptual designs for an HRM to be used as a substitute for the liquid rocket motor(LRM)of the Ascent Propulsion *** conceptual design results show that HRMs have several advantages as an alternative to the LRM of the Ascent Propulsion System,including nontoxic propellant combination,small motor volume,and comparable functions,such as restarting and *** of the DDO and UDO results indicate that the UDO method achieves more robust and reliable optimal designs than the DDO *** probabilistic UDO method can be used to develop better conceptual designs for HRMs.

关键词： hybrid rocket motor deterministic design optimization uncertainty-based design optimization sensitivity analysis manned lunar landing

DUAL RECIPROCITY BOUndARY ELEMENT METHOD FOR FLEXURAL WAVES IN THIN PLATE WITH CUTOUT

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Applied Mathematics and Mechanics(English Edition) 2005年第12期26卷 1564-1573页

作者：高锁文汪越胜章梓茂马兴瑞 institute of Engineering Mechanics Beijing Jiaotong University china aerospace science and technology corporation

The theoretical analysis and numerical calculation of scattering of elastic waves and dynamic stress concentrations in the thin plate with the cutout was studied using dual reciprocity boundary element method （DRM）. Based on the work equivalent law, the dual reciprocity boundary integral equations for flexural waves in the thin plate were established using static fundamental solution. As illustration, numerical results for the dynamic stress concentration factors in the thin plate with a circular hole are given. The results obtained demonstrate good agreement with other reported results and show high accuracy.

关键词： thin plate DRM scattering of flexural wave dynamic stress concentration

A Pulsed Pseudolite Signal Acquisition Method Using Signal Coverage Recursion FFT 36

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A Pulsed Pseudolite Signal Acquisition Method Using Signal C...