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Turbo-shaft engine adaptive neural network control based on nonlinear state space equation

Chinese Journal of Aeronautics 2024年第4期37卷 493-507页

作者： Ziyu GU Qiuhong LI Shuwei PANG Wenxiang ZHOU Jichang WU Chenyang ZHANG Jiangsu Province Key Laboratory of Aerospace Power system Nanjing University of Aeronautics and AstronauticsNanjing 210016China AECC Hunan Aviation Powerplant research institute Zhuzhou 412002China

Intelligent Adaptive Control(AC) has remarkable advantages in the control system design of aero-engine which has strong nonlinearity and uncertainty. Inspired by the Nonlinear Autoregressive Moving Average(NARMA)-L2 adaptive control, a novel Nonlinear State Space Equation(NSSE) based Adaptive neural network Control(NSSE-AC) method is proposed for the turbo-shaft engine control system design. The proposed NSSE model is derived from a special neural network with an extra layer, and the rotor speed of the gas turbine is taken as the main state variable which makes the NSSE model be able to capture the system dynamic better than the NARMA-L2 model. A hybrid Recursive Least-Square and Levenberg-Marquardt(RLS-LM) algorithm is advanced to perform the online learning of the neural network, which further enhances both the accuracy of the NSSE model and the performance of the adaptive controller. The feedback correction is also utilized in the NSSE-AC system to eliminate the steady-state tracking error. Simulation results show that, compared with the NARMA-L2 model, the NSSE model of the turboshaft engine is more accurate. The maximum modeling error is decreased from 5.92% to 0.97%when the LM algorithm is introduced to optimize the neural network parameters. The NSSE-AC method can not only achieve a better main control loop performance than the traditional controller but also limit all the constraint parameters efficiently with quick and accurate switching responses even if component degradation exists. Thus, the effectiveness of the NSSE-AC method is validated.

关键词： Adaptive control systems Turbo-shaft engine Neural network Nonlinear state space equation NARMA-L2

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Data-driven surrogate model for aerodynamic design using separable shape tensor method

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Chinese Journal of Aeronautics 2024年第9期37卷 41-58页

作者： Bo PANG Yang ZHANG Junlin LI Xudong WANG Min CHANG Junqiang BAI State Key Laboratory for Srrenglh and Vibration of Mechanical Structures Xi'an Jiaotong UniversityXi'an 710049China Unmanned system research institute Northwestern Polytechmical UniversityXi'an 710072China

In the context of increasing dimensionality of design variables and the complexity of con-straints,the effcacy of Surrogate-Based Optimization(SBO)is *** traditional linear and nonlinear dimensionality reduction algorithms are mainly to decompose the mathematical matrix composed of design variables or objective functions in various forms,the smoothness of the design space cannot be guaranteed in the process,and additional constraint functions need to be added in the optimization,which increases the calculation *** study presents a new parameterization method to improve both problems of *** new parameterization is addressed by decoupling affine transformations(dilation,rotation,shearing,and translation)within the Grassmannian sub-manifold,which enables a separate representation of the physical information of the airfoil in a high-dimensional *** upon this,Principal Geodesic Analysis(PGA)is employed to achieve geometric control,compress the design space,reduce the number of design variables,reduce the dimensions of design variables and enhance predictive performance during the surrogate optimiza-tion *** comparison,a dimensionality reduction space is defined using 95%of the energy,and RAE 2822 for transonic conditions are used as *** method significantly enhances the optimization efficiency of the surrogate model while effectively enabling geometric *** three-dimensional problems,it enables simultaneous design of planar shapes for various components of the aircraft and high-order perturbation *** was applied to the ONERA M6 wing,achieving a lift-drag ratio of 18.09,representing a 27.25%improvement com-pared to the baseline *** comparison to conventional surrogate model optimization methods,which only achieved a 17.97%improvement,this approach demonstrates its superiority.

关键词： Aerodynamicdesign Grassmannian manifold Shape parameterization Surrogate-based optimiza-tion Data dimensionality reduction

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Visualization analysis of research hotspots and trends on gastrointestinal tumor organoids

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World Journal of Gastrointestinal Oncology 2024年第6期16卷 2826-2841页

作者： Gang Wang Tao Liu Wen-Ting He School of Basic Medical Sciences Lanzhou UniversityLanzhou 730000Gansu ProvinceChina digestive system Tumor Prevention and Treatment and Translational Medicine Engineering Innovation Center of Lanzhou University Lanzhou UniversityLanzhou 730000Gansu ProvinceChina digestive system Tumor Translational Medicine Engineering research Center of Gansu Province Lanzhou UniversityLanzhou 730000Gansu ProvinceChina The Second Hospital&Clinical Medical School Lanzhou UniversityLanzhou 730030Gansu ProvinceChina

BACKGROUND Gastrointestinal tumor organoids serve as an effective model for simulating cancer in vitro and have been applied in basic biology and preclinical *** over a decade of development and increasing research achievements in this field,a systematic and comprehensive analysis of the research hotspots and future trends is *** To address this problem by employing bibliometric tools to explore the publication years,countries/regions,institutions,journals,authors,keywords,and references in this *** The literature was collected from Web of Science ***-6.2R4,a widely used bibliometric analysis software package,was used for institutional analysis and reference burst *** 1.6.19 was used for journal cocitation analysis,author co-authorship and co-citation ***‘online platform for bibliometric analysis(https://***/app)’was used to assess the total number of publications and the cooperation relationships between ***,we employed the bibliometric R software package(version R.4.3.1)in R-studio,for a comprehensive scientific analysis of the *** Our analysis included a total of 1466 publications,revealing a significant yearly increase in articles on the study of gastrointestinal tumor *** United States(n=393)and Helmholtz Association(n=93)have emerged as the leading countries and institutions,respectively,in this field,with Hans Clevers and Toshiro Sato being the most contributing *** most influential journal in this field is *** most impactful reference is"Long term expansion of epithelial organs from human colon,adenoma,adenocarcinoma,and Barrett's epithelium".Keywords analysis and citation burst analysis indicate that precision medicine,disease modeling,drug development and screening,and regenerative medicine are the most cutting-edge *** focal points were further detailed based on the *** This bibl

关键词： Gastrointestinal tumor organoids Bibliometric analysis Drug development and screening Model CiteSpace

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New advances in the study of Tethyan Geodynamic system

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Science China Earth Sciences 2024年第3期67卷 874-878页

作者： Lin DING State Key Laboratory of Tibetan Plateau Earth system Science(LATPES) Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China

Tethyan Ocean was initially proposed by Austrian geologist Eduard Suess in 1893. The study of the Tethyan evolution by European geologists has led to the development of modern geology, but not to the establishment of plate tectonics theory(Trümpy, 2001). With the progress in various studies, the concept of Tethys has evolved from a Mesozoic ocean into three long-term evolving oceans:Proto-Tethys, Paleo-Tethys, and Neo-Tethys (Figure 1), and their life cycles cover the entire Phanerozoic era (Wu et al., 2020).

关键词： geology Mesozoic ocean

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Combined effect of WS_(2) and Ti_(3)C_(2)T_(x) MXene favors oil-based ultra-low friction on rough steel-steel interface at elevated temperatures

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Science China(Technological Sciences) 2024年第7期67卷 1991-2002页

作者： LIU YangQin CHEN Lei WANG Yang QIAN LinMao Tribology research institute State Key Laboratory of Rail Transit Vehicle SystemSchool of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China Key Laboratory of Advanced Technologies of Materials(Ministry of Education) Research Institute of Frontier ScienceSouthwest Jiaotong UniversityChengdu 610031China

The lubrication performance of liquids is severely restricted and is degraded in high-temperature environments. Stable and reliable lubrication in high temperature environments has been a long-standing goal in various industrial fields. In this study,WS_(2)and Ti_(3)C_(2)T_(x)MXene nanoflakes were used as oil-based lubricant additives to generate ultra-low friction and even superlubricity(friction coefficient of ~0.007) at elevated temperatures(400℃), which has hitherto not been achieved by both individual pristine materials, WS_(2)and Ti_(3)C_(2)T_(x)MXene. Viscosity and thermogravimetric characterization revealed improvements in the high-temperature rheological properties and thermal stability of the lubricating base oil, indicating improved loadbearing and continuous lubrication capabilities at elevated temperatures. X-ray photoelectron spectroscopy, transmission electron microscopy, and atomic force microscopy demonstrated that the formation of an iron/titanium/tungsten-rich oxide lubricious thin film at the sliding interface reduced the interfacial shear stress, which was responsible for the observed friction and wear reductions at high contact pressures(> 1.1 GPa). Although the titanium/tungsten oxide film was gradually removed after prolonged sliding, a sufficiently thick iron oxide film maintained a low friction coefficient for at least 2 h. The improved surface quality facilitates the achievement of ultra-low friction and reduced wear. The proposed lubrication methodology has a broad utilization potential as a wear-reduction strategy across various industrial fields at elevated temperatures.

关键词： ultra-low friction high-temperature wear reduction lubricating additive tungsten disulfide MXene

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Time-varying parameters estimation with adaptive neural network EKF for missile-dual control system

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Journal of systems Engineering and Electronics 2024年第2期35卷 451-462页

作者： YUAN Yuqi ZHOU Di LI Junlong LOU Chaofei School of Astronautics Harbin Institute of TechnologyHarbin 150001China Beijing institute of Electronic system Engineering Beijing 100854China

In this paper, a filtering method is presented to estimate time-varying parameters of a missile dual control system with tail fins and reaction jets as control variables. In this method, the long-short-term memory(LSTM) neural network is nested into the extended Kalman filter(EKF) to modify the Kalman gain such that the filtering performance is improved in the presence of large model uncertainties. To avoid the unstable network output caused by the abrupt changes of system states,an adaptive correction factor is introduced to correct the network output online. In the process of training the network, a multi-gradient descent learning mode is proposed to better fit the internal state of the system, and a rolling training is used to implement an online prediction logic. Based on the Lyapunov second method, we discuss the stability of the system, the result shows that when the training error of neural network is sufficiently small, the system is asymptotically stable. With its application to the estimation of time-varying parameters of a missile dual control system, the LSTM-EKF shows better filtering performance than the EKF and adaptive EKF(AEKF) when there exist large uncertainties in the system model.

关键词： long-short-term memory(LSTM)neural network extended Kalman filter(EKF) rolling training time-varying parameters estimation missile dual control system

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Knowledge and data jointly driven aeroengine gas path performance assessment method

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Chinese Journal of Aeronautics 2024年第5期37卷 533-557页

作者： Zhe WANG Xuyun FU Rui ZHANG Zhengfeng BAI Xiangzhao XIA Wei JIANG Department of Mechanical Engineering Harbin Institute of TechnologyWeihai 264209China Weihai Key Laboratory of Intelligent Operation and Maintenance Harbin Institute of TechnologyWeihai 264209China Control system Design Laboratory AECC ShenYang Engine Research InstituteShenyang 110015China

Aeroengines,as the sole power source for aircraft,play a vital role in ensuring flight *** gas path,which represents the fundamental pathway for airflow within an aeroengine,directly impacts the aeroengine's performance,fuel efficiency,and ***,timely and accurate evaluation of gas path performance is of paramount *** paper proposes a knowledge and data jointly driven aeroengine gas path performance assessment method,combining Fingerprint and gas path parameter deviation ***,Fingerprint is used to correct gas path parameter deviation values,eliminating parameter shifts caused by non-component performance ***,coarse errors are removed using the Romanovsky criterion for short-term data divided by an equal-length overlapping sliding ***,an Ensemble Empirical Mode Decomposition and Non-Local Means(EEMD-NLM)filtering method is designed to“clean”data noise,completing the preprocessing for gas path parameter deviation ***,based on the characteristics of gas path parameter deviation values,a Dynamic Temporary Blended Network(DTBN)model is built to extract its temporal features,cascaded with Multi-Layer Perceptron(MLP),and combined with Fingerprint to construct a Dynamic Temporary Blended AutoEncoder(DTB-AutoEncoder).Eventually,by training this improved autoencoder,the aeroengine gas path multi-component performance assessment model is formed,which can sufficiently decouple the nonlinear mapping relationship between aeroengine gas path multi-component performance degradation and gas path parameter deviation values,thereby achieving the performance assessment of engine gas path *** practical application cases,the effectiveness of this model in assessing the aeroengine gas path multi-component performance is verified.

关键词： Performance assessment Aeroengine Fingerprint Gas path parameter deviation values Jointly drive

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Influence of Film Thickness on Nanofabrication of Graphene Oxide

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Nanomanufacturing and Metrology 2024年第2期7卷 13-25页

作者： Chuan Tang Lei Chen Linmao Qian Tribology research institute The State Key Laboratory of Rail Vehicle SystemSchool of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Nanofabrication of two-dimensional materials through mechanical machining is normally influenced by not only process parameters such as load and velocity but also intrinsic properties such as strength and ***,we examined the effects of graphene oxide(GO)film thickness on nanofabrication on the plane surfaces and at the step edges using scanning probe microscope *** material removal of GO initiates at the load above a critical value,which strongly depends on film thickness and *** the increase in film thickness,the critical load decreases monotonically on the plane surfaces but increases gradually at the step ***,the critical load for the GO monolayer at the step edges is at least 25 times lower than that on the plane surfaces,and the gap decreases to around 3 times when GO thickness increases to four ***,mechanical nanofabrication initiating from the GO step edge allows producing various nanopatterns under extremely low loads around 1 ***,the GO nanostructures are deoxidized by annealing at 800°C in high-purity argon to restore their highly functionalized conjugated structures,which are supported by X-ray diffraction and Raman *** work provides a novel approach to fabricating graphene-like nanostructures by deoxidizing GO after nanofabrication,which holds significant potential for applications in graphene-based devices.

关键词： Graphene oxide Nanofabrication Film thickness step edge Nanopattern Deoxidized treatment

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A versatile humanoid robot platform for dexterous manipulation and human-robot collaboration

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CAAI Transactions on Intelligence Technology 2024年第2期9卷 526-540页

作者： Xin Shu Fenglei Ni Xinyang Fan Shuai Yang Changyuan Liu Baoxu Tu Yiwei Liu Hong Liu State Key Laboratory of Robotics and system Harbin Institute of TechnologyHarbinChina

Humanoid robots have attracted much attention by virtue of their compatibility with human ***,biped humanoids with immense promise still cannot function steadily and reliably in real-world settings in the current ***,rationally combining a humanoid robot with different stable mobile platforms is a favoured solution for diverse ***,a new versatile humanoid robot platform,aiming to provide a generic solution that can be flexibly deployed in diverse scenarios,for example,indoors and fields is *** humanoid robot platform incorporates multimodal perception,and extensible interfaces on hardware and software,allowing it to be rapidly integrated with different mobile platforms and end-effectors,only through easyto-assemble ***,the platform has achieved impressive integration,lightness,dexterity,and strength in its class,with human-like size and rich perception,targeted to have human-intelligent manipulation skills for human-engineered ***,this article elaborates on the reasoning behind the design choices,and outlines each ***,the essential performance of the platform is successfully demonstrated in a set of experiments with precise and dexterous manipulation,and human–robot collaboration requirements.

关键词： intelligent robots robotics

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Effect of the yaw angle on turbulent flow structures around the submarine model

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Journal of Hydrodynamics 2024年第3期36卷 421-434页

作者： Yi-jing Hu Yi Qu Qin Wu Biao Huang School of Mechanical Engineering Beijing Institute of TechnologyBeijing100081China Beijing institute of Electronic system Engineering Beijing100854China

The objective of this paper is to investigate the turbulent flow structures around the submarine model and evaluate the effect of the yaw angle on the turbulent flow *** large eddy simulation based on the boundary data immersion method is used to *** computational domain consists of 1.2×10^(8)uniformly distributed Cartesian orthogonal grid nodes to capture the basic flow characteristics around the *** pressure coefficient,friction coefficient and wake velocity distribution are in good agreement with the experimental *** different types of vortex structures were mainly captured around the model,including horseshoe vortex,sail tip vortex and crossflow separation *** the increase of the yaw angle,the asymmetry of the horseshoe vortex and the tip vortex gradually increases,and the vortex strength of the vortex leg on the windward of the horseshoe vortex and the vortex strength of the tip vortex also increase *** the crossflow separation vortex,the flow separation zone gradually expands and migrates downstream with the increase of the yaw angle.

关键词： Vortex structure submarine model boundary data immersion method yaw angle

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