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Integrated Observer-based Fixed-time Control with Backstepping Method for Exoskeleton Robot

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International Journal of Automation and computing 2020年第1期17卷 71-82页

作者： gao-wei zhang Peng Yang Jie Wang Jian-Jun Sun Yan zhang School of Artificial Intelligence Hebei University of TechnologyTianjin 300130China Enginnering Research Center of Intelligent Rehabilitation and Detection Technology Ministry of EducationTianjin 300130China

To achieve the fast convergence and tracking precision of a robotic upper-limb exoskeleton,this paper proposes an observer-based integrated fixed-time control scheme with a backstepping ***,a typical 5 DoF(degrees of freedom)dynamics is constructed by Lagrange equations and processed for control ***,second-order sliding mode controllers(SOSMC)are developed and novel sliding mode surfaces are introduced to ensure the fixed-time convergence of the human-robot *** the reaching time and settling time are proved to be bounded with certain values independent of initial system *** the purpose of rejecting the matched and unmatched disturbances,nonlinear fixed-time observers are employed to estimate the exact value of disturbances and compensate the controllers ***,the synthesis of controllers and disturbance observers is adopted to achieve the excellent tracking performance and simulations are given to verify the effectiveness of the proposed control strategy.

关键词： Upper-limb exoskeleton sliding mode control(SMC) fixed-time control disturbance observe backstepping

Effect of microstructure and defects on the magnetostriction of<110> oriented TDT-110 alloys

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Journal of University of Science and Technology Beijing 2008年第1期15卷 53-57页

作者： Haijun Tang Xuexu gao wei Wu Maocai zhang Shouzeng Zhou State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

〈110〉 oriented rods of TbDyFe giant magnetostrictive alloys have been prepared with the help of the zone melting directional solidification technique with a high temperature gradient. To acquire optimal magnetostrictive properties at low magnetic field, the TbDyFe alloys have been heat-treated at different temperatures and cooled at different rates. The relationships between the proc- ess of the heat treatment, microstructure, defects, and magnetostrictive properties of the TbDyFe materials have been studied. 2008 University of Science and Technology Beijing. All rights reserved.

关键词： TbDyFe heat treatment microstructure defect magnetostriction

Effect of oxide inclusions on MnS precipitates and tensile mechanical property of high-strength low-alloy steel

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Journal of Iron and Steel Research International 2024年第5期31卷 1210-1220页

作者： Xiao-yong gao Hong wei Li-feng zhang School of Mechanical Engineering Yanshan UniversityQinhuangdao066004HebeiChina School of Materials Science and Engineering Yanshan UniversityQinhuangdao066004HebeiChina School of Mechanical and Materials Engineering North China University of TechnologyBeijing100144China

The key role of oxide inclusions on the microstructure and mechanical property of a high-strength low-alloy steel was *** field emission scanning electron microscope equipped with energy-dispersive spectrometry was used to characterize MnS *** inclusions play an important role in the shape control of MnS *** oxides fovored to decrease the size and the aspect ratio of MnS *** less oxide inclusions in the steel,approximately over 16.7%MnS precipitates were with aspect ratio a>5 and pure MnS precipitates accounted for 75.9%in ***,with more oxide inclusions in the steel,only 7.4%MnS precipitates were with a>5 and pure MnS precipitates accounted for 60.1%in *** of MnS by oxide inclusions improved the strength and inhibited the *** oxide inclusions in the steel increased the yield strength and tensile strength of the steel in both longitudinal and transverse directions,and lowered the anisotropy of the mechanical property.

关键词： High-strength low-alloy steel MnS Oxide inclusion Mechanical property Anisotropy

Effect of mesopore spatial distribution of HZSM-5 catalyst on zinc state and product distribution in 1-hexene aromatization

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Chinese Journal of Chemical Engineering 2024年第3期67卷 16-26页

作者： Chenhao wei Di gao Guohao zhang Liang Zhao Jinsen gao Chunming Xu The State Key Lab of Heavy Oil Processing China University of Petroleum(Beijing)Beijing 102249China SINOPEC Research Institute of Petroleum Processing Co. Ltd.Beijing 100083China

1-hexene aromatization is a promising technology to convert excess olefin in fluid catalytic cracking(FCC)gasoline to high-value benzene(B),toluene(T),and ***,the increasing market demand of xylene has put forward higher requirements for new generation of *** increasing xylene yield in 1-hexene aromatization,the effect of mesopore structure and spatial distribution on product distribution and Zn loading was *** with different mesopore spatial distribution were prepared by post-treatment of parent HZSM-5 zeolite,including NaOH treatment,tetra-propylammonium hydroxide(TPAOH)treatment,and *** was found the evenly distributed mesopore mainly prolongs the catalyst lifetime by enhancing diffusion properties but reduces the aromatics selectivity,as a result of damage of micropores close to the catalyst *** the selectivity of high-value xylene can be highly promoted when the mesopore is mainly distributed interior the ***,the state of loaded Zn was also affected by mesopores spatial *** the optimized catalyst,the xylene selectivity was enhanced by 12.4%compared with conventional Zn-loaded parent HZSM-5 catalyst at conversion over 99%.It was attributed to the synergy effect of mesopores spatial distribution and optimized acid *** work reveals the role of mesopores in different spatial positions of 1-hexene aromatization catalysts in the reaction process and the influence on metal distribution,as well as their synergistic effect two on the improvement of xylene selectivity,which can improve our understanding of catalyst pore structure and be helpful for the rational design of high-efficient catalyst.

关键词： 1-Hexene aromatization Alkali treatment Xylene selectivity Mesopores Zinc state

An in-situ polymerized interphase engineering for high-voltage allsolid- state lithium-metal batteries

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Nano Research 2024年第4期17卷 2687-2692页

作者： Lu Nie Shaojie Chen Mengtian zhang Tianyi gao Yuyao zhang Ran wei Yining zhang wei Liu School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Tsinghua-Berkeley Shenzhen Institute&Tsinghua Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055China

All-solid-state lithium batteries(ASSLBs)have attracted great interest due to their promising energy density and strong ***,the interface issues,including large interfacial resistance between electrode and electrolyte and low electrochemical stability of solid-state electrolytes against high-voltage cathodes,have restricted the development of high-voltage ***,we report an ASSLB with stable cycling by adopting a conformal polymer interlayer in-situ formed at the Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)–cathode *** polymer can perfectlyﬁll the voids and create a stable interface contact between LLZTO and *** addition,the electric field across the polymer interlayer is reduced compared with pure solid polymer electrolyte(SPE),which facilitates the electrochemical stability with high-voltage *** all-solid-state Li|LLZTO-SPE|LiFe_(0.4)Mn_(0.6)PO_(4)(LMFP)cells achieve a low interface impedance,high specific capacity,and excellent cycling *** work presents an effective and practical strategy to rationally design the electrode–electrolyte interface for the application of high-voltage ASSLBs.

关键词： all-solid-state lithium batteries interface contact electric field electrochemical stability

Lift-Off Effect of Koch and Circular Differential Pickup Eddy Current Probes

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 283-293页

作者： Guolong Chen Zheng Cao Shuaishuai zhang Ji wei wei gao Wuyin Jin School of Mechanical and Electrical Engineering Lanzhou University of TechnologyLanzhou 730050China

A flexible or planar eddy current probe with a differential structure can suppress the lift-off noise during the inspection of ***,the extent of the lift-off effect on differential probes,including different coil structures,*** this study,two planar eddy current probes with differential pickup structures and the same size,Koch and circular probes,were used to compare lift-off *** eddy current distributions of the probes perturbed by 0°and 90°cracks were obtained by finite element *** analysis results show that the 90°crack can impede the eddy current induced by the Koch probe even further at relatively low lift-off *** peak-to-peak values of the signal output from the two probes were compared at different lift-off distances using finite element analysis and experimental *** addition,the effects of different frequencies on the lift-off were studied *** results show that the signal peak-to-peak value of the Koch probe for the inspection of cracks in 90°orientation is larger than that of the circular probe when the lift-off distance is smaller than 1.2 *** addition,the influence of the lift-off distance on the peak-to-peak signal value of the two probes was studied via *** indicates that the influence becomes more evident with an increase in excitation *** research discloses the lift-off effect of differential planar eddy current probes with different coil shapes and proves the detection merit of the Koch probe for 90°cracks at low lift-off distances.

关键词： Eddy current testing Differential pickup probe Fractal Koch curve Flexible eddy current probe

Olfactory ensheathing cell transplantation in 106 patients with old spinal cord injury Differences in ages,sexes,disease courses,injured types and sites

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Neural Regeneration Research 2007年第6期2卷 380-384页

作者： Zuncheng Zheng Chao Liu Lin zhang Rui gao Shugang wei Kun zhang Lei zhang Department of Neurosurgery Taian Rongjun Hospital of Shandong Province Taian 271000 Shandong Province China

BACKGROUND： It has been demonstrated that the transplantation of olfactory ensheathing cell （OEC） can promote the recovery of neurological function through ameliorating the local internal environment in spinal cord injury. OBJECTIVE： To evaluate the recent efficacy of OEC transplantation on old spinal cord injury. DESIGN： A self-controlled experiment. SETTING： Department ofNeurosurgery, Taian Rongjun Hospital of Shandong Province. PARTICIPANTS： Totally 106 inpatients with old spinal cord injury were selected from the Department of Neurosurgery, Taian Rongjun Hospital of Shandong Province from June 2004 to December 2006, including 97 males and 9 females. Inclusive criteria： ① Complete data; ② Informed with the fact; ③No further recover neurological function after drug therapy （neurotrophic factor, GM-1）, traditional Chinese medicine, physiotherapy and rehabilitative exercises; ④ No obvious compression of the injured spinal cord displayed by MRI examination. METHODS： ① The olfactory bulb was obtained from embryo of induced labor in middle pregnancy above 4 months supplied voluntarily by pregnant women, and the survived cells after purification and culture for 1 - 2 weeks were collected. Dura mater was incised by posterior approach, then the cultured OEC suspension was transplanted to corresponding regions by means of multi-target injection using microscope. ② The patients were evaluated for twice with the standards suggested by American Spinal Injury Association （ASIA） at admission and 2 - 4 weeks postoperatively, in order to investigate the efficacy in different age groups, different sites and at different time points after the OEC transplantation. ③ Standards for evaluation： The International Standard for Neurological and Functional Classification of Spinal Cord Injury set by ASIA： The highest score of motor function was 100 points; The highest score of sensory function was 112 points for light touch and 112 for acupuncture sense. Frankel grading modified by ASIA in

关键词： olfactory spinal cord injuries transplantation recovery of function

ControlService: a containerized solution for control-algorithm-as-a-service in cloud control systems

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Science China(Information Sciences) 2024年第8期67卷 172-189页

作者： Chenggang SHAN Runze gao Zhen YANG wei zhang Yuanqing XIA School of Artificial Intelligence Zaozhuang University School of Automation Beijing Institute of Technology

As an extension of networked control systems, cloud control systems(CCSs) have emerged as a new control paradigm to improve the service quality of emerging control missions, such as data-driven modeling and automated vehicles. Existing studies have used the workflow-based restructured method to optimize the computation-intensive algorithms in the CCSs. However, the challenges here are how to define and submit these algorithms' workflows as cloud services and execute these algorithms' workflows in a containerized manner. Based on these challenges, we propose a containerized solution for the control-algorithm-as-a-service(C3aS) in the CCSs, namely Control Service. It offers the control algorithm as a cloud workflow service and uses a customized workflow engine to realize the containerized execution. First, we employ a cloud workflow representation method to define a control algorithm into an abstract cloud workflow form. Afterward, we provide a cloud service representation of the abstract cloud workflow. Next, we design a workflow engine and submit the cloud service to this workflow engine to implement containerized execution of this cloud service in the CCSs. In the experiment, we discuss the cloud service form and containerized implementation of the subspace identification method. Experimental results show that the proposed Control Service has significant performance advantages in computational time, reduction percentage, and speedup ratio compared with the baseline method.

关键词： cloud control systems control-algorithm-as-a-service containerization workflow engine cloud workflow service subspace identification

Layerwise third-order shear deformation theory with transverse shear stress continuity for piezolaminated plates

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CHINESE JOURNAL OF AERONAUTICS 2024年第9期37卷 490-505页

作者： gao, Yingshan zhang, Shunqi Hu, wei Ma, Songyun Markert, Bernd Shanghai Univ Sch Mech Engn & Automat Shanghai 200444 Peoples R China Shanghai Univ Key Lab Silicate Cultural Rel Conservat Minist Educ Shanghai 200444 Peoples R China Rhein Westfal TH Aachen Inst Gen Mech D-52062 Aachen Germany

Regarding laminated structures, an electromechanically coupled Finite Element (FE) model based on Layerwise Third-Order Shear Deformation (LW-TOSD) theory is proposed for static and dynamic analysis. LW-TOSD ensures the continuity of in-plane displacements and transverse shear stresses. The current LW-TOSD can be applied to arbitrary multi-layer laminated structures with only seven Degrees of Freedom (DOFs) for each element node and eliminates the use of the shear correction factors. Moreover, a shear penalty stiffness matrix is constructed to satisfy artificial constraints to optimize the structural shear strain. A dynamic finite element model is obtained based on LW-TOSD using the Hamilton's principle. First, the accuracy of the current model is validated by comparing with literature and ABAQUS results. Then, this study carries out numerical investigations of piezolaminated structures for different width-to-thickness ratios, length-to-width ratios, penalty stiffness matrix, boundary conditions, electric fields and dynamics. (c) 2024 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.

关键词： Laminated structures Piezolaminated structures Third-order shear deforma- tion theory Shear stress continuity Electromechanically coupled LAMINATED COMPOSITE FREE-VIBRATION SANDWICH PLATES