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Control Design for Harmonic Disturbance Rejection for Robot Manipulators with Bounded Inputs

Chinese Journal of Mechanical Engineering 2011年第2期24卷 248-256页

作者： YAO Yu wang Xiaochen HE fenghua Control and Simulation Center Harbin Institute of Technology Harbin 150080 China

Currently most of control methods are of one degree of freedom（1-DOF） control structure for the robot systems which are affected by unmeasurable harmonic disturbances,at the same time in order to obtain perfect disturbance attenuation level,the controller gain must be *** practice,however,for robotic actuators,there are physical constraints that limit the amplitude of the available *** paper considers the problem of tracking control under input constraints for robot manipulators which are affected by unmeasurable harmonic disturbances.A new control scheme is proposed for the problem,which is composed of a parameter-dependent nonlinear observer and a tracking *** parameter-dependent nonlinear observer,designed based on the internal model principle,can achieve an estimation and compensation of a class of harmonic disturbances with unknown *** tracking controller,designed via adaptive control techniques,can make the systems asymptotically track the desired *** the control design,the continuous piecewise differentiable increasing function is used to limit control input amplitude,such that the control input saturation is *** Lyapunov stability of closed loop systems is *** validate proposed control scheme,simulation results are provided for a two link horizontal robot *** simulation results show that the proposed control scheme ensures asymptotic tracking in presence of an uncertain external disturbance acting on the *** important feature of the methodology consists of the fact that the designed controller is of 2-DOF control structure,namely,it has the ability to overcome the conflict between controller gain and robustness against external disturbances in the traditional 1 -DOF control structure framework.

关键词： tracking control of robot harmonic disturbance rejection internal model principle input constraint adaptive control

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Blind reconstruction of convolutional code based on segmented Walsh-Hadamard transform

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Journal of Systems Engineering and Electronics 2014年第5期25卷 748-754页

作者： fenghua wang Hui Xie Zhitao Huang College of Electronic Science and Engineering National University of Defense Technology Department of Electronic and Optics Engineering Ordance Engineering College

Walsh-Hadamard transform （WriT） can solve linear error equations on Field F2, and the method can be used to recover the parameters of convolutional code. However, solving the equations with many unknowns needs enormous computer memory which limits the application of WriT. In order to solve this problem, a method based on segmented WriT is proposed in this paper. The coefficient vector of high dimension is reshaped and two vectors of lower dimension are obtained. Then the WriT is operated and the requirement for computer memory is much reduced. The code rate and the constraint length of convolutional code are detected from the Walsh spectrum. And the check vector is recovered from the peak position. The validity of the method is verified by the simulation result, and the performance is proved to be optimal.

关键词： convolutional code blind reconstruction Walsh-Hadamard transform (WriT) tinear error equation.

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Blind reconstruction of linear scrambler

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Journal of Systems Engineering and Electronics 2014年第4期25卷 560-565页

作者： Hui Xie fenghua wang Zhitao Huang Department of Electronic and Optics Engineering Ordance Engineering College College of Electronic Science and Engineering National University of Defense Technology

An algorithm based on eigenanalysis technique and Walsh-Hadamard transform （WriT） is proposed. The algorithm contains two steps. Firstly, the received sequence is divided into temporal windows, and a covariance matrix is computed. The linear feedback shift register （LFSR） sequence is reconstructed from the first eigenvector of this matrix. Secondly, equations according to the recovered LFSR sequence are constructed, and the Walsh spectrum corresponding to the equations is computed. The feedback polynomial of LFSR is estimated from the Walsh spectrum. The validity of the algorithm is verified by the simulation result. Finally, case studies are presented to illustrate the performance of the blind reconstruction method.

关键词： scrambler linear feedback shift register (LFSR) reconstruction eigenanalysis Walsh-Hadamard transform.

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The texture and its optimization in magnesium alloy

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Journal of Materials Science & Technology 2020年第7期42卷 175-189页

作者： Jialin Wu Li Jin Jie Dong fenghua wang Shuai Dong National Engineering Research Center of Light Alloy Net Forming Shanghai Jiao Tong UniversityShanghai 200240China

The crystallographic orientations are generally non-random in wrought Mg alloy,which will lead to their macroscopic physical properties to be *** the texture evolution in processing of Mg alloy billets and its effect on mechanical properties is therefore an important project for all scientists and engineers in material *** paper is concerned with the description of texture,with the mechanisms of texture evolution and with the interrelationships between texture and mechanical properties in Mg *** is a full review of understanding of the basic mechanism on texture evolution,of texture altering by alloying or processing,and of the mechanism of texture ***,it provides theories necessary and available techniques to develop high-performance Mg wrought with optimized texture in the field.

关键词： Magnesium alloy Texture Rare earth(RE) Anisotropic Mechanical property

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Cyclic shear deformation and fatigue of extruded Mg-Gd-Y magnesium alloy

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Journal of Materials Science & Technology 2020年第4期39卷 74-81页

作者： fenghua wang Miaolin Feng Yanyao Jiang Jie Dong Zhenyan Zhang National Engineering Research Center of Light Alloy Net Forming&State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai200240China Department of Engineering Mechanics Shanghai Jiao Tong UniversityShanghai200240China Department of Mechanical Engineering University of NevadaRenoNV89557USA Shanghai Light Alloy Net Forming National Engineering Research Center Co.Ltd Shanghai201615China

Deformation and fatigue of extruded Mg-8.0 Gd-3.0 Y-0.5 Zr(GW83, wt%) magnesium(Mg) alloy were experimentally investigated under cyclic torsion using tubular specimen fabricated along the extrusion direction. The controlled shear strain amplitudes ranged from 0.606% to 4.157%. Twinning and detwinning of extension twins are observed to take place during cyclic torsion and the shear stress-shear strain hysteresis loops display a perfectly symmetric shape at all tested strain amplitudes. Marginal cyclic softening is observed when the shear strain amplitude is higher than 1.732%. The strain-life fatigue curve shows two kink points, corresponding to the shear strain amplitude of 1.040% and 1.732%, *** the shear strain amplitude is higher than the upper kink point, early fatigue crack is found to initiate on the maximum shear plane. When the strain amplitude is lower than the lower kink point,fatigue cracking is parallel to the maximum tensile plane. At an identical equivalent strain amplitude,the fatigue life under pure shear is much higher than that under tension-compression. The fatigue life of extruded GW83 alloy is much higher than that of extruded AZ31 B alloy at the same plastic strain energy density.

关键词： Mg-Gd-Y-Zr magnesium alloy Cyclic torsion Shear fatigue Twinning

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真菌毒素降解酶及其结构和功能研究进展

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核农学报 2025年第1期39卷 140-156页

作者：王凤华牛锦璐邓俊劲晏石娟张军吴绍文甘肃农业大学资源与环境学院甘肃兰州730070 猪禽种业全国重点实验室/广东省农业科学院农业生物基因研究中心广东广州510640

真菌毒素作为真菌次级代谢产生的一类化合物,其化学结构稳定并可在食物链中积累,严重威胁人类和禽畜健康并造成重大经济损失。生物酶降解法因安全性高、环境友好等优点而在真菌毒素脱毒方面展现出极大的应用前景。本文系统总结黄曲霉毒... 详细信息

真菌毒素作为真菌次级代谢产生的一类化合物,其化学结构稳定并可在食物链中积累,严重威胁人类和禽畜健康并造成重大经济损失。生物酶降解法因安全性高、环境友好等优点而在真菌毒素脱毒方面展现出极大的应用前景。本文系统总结黄曲霉毒素、玉米赤霉烯酮、脱氧雪腐镰刀菌烯醇、赭曲霉毒素和伏马菌素等常见真菌毒素降解酶的挖掘和功能分析,重点关注利用X射线晶体学等方法解析降解酶三维结构、揭示其催化机制的研究进展,并比较分析计算方法预测的结合口袋与试验确定的活性中心;阐述基于蛋白质结构的理性设计策略在真菌毒素降解酶改造中的应用,并讨论利用计算生物学方法预测蛋白质结构和功能、解析酶的作用机制并指导降解酶设计的潜力。本文可为解决食品和饲料中的真菌毒素污染问题提供新思路。

关键词：真菌毒素降解酶结构蛋白质设计

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Mechanical Behavior and Microstructure Evolution of a Rolled Magnesium Alloy AZ31B Under Low Stress Triaxiality

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Journal of Materials Science & Technology 2016年第12期32卷 1282-1288页

作者： Hongchen Pan fenghua wang Li Jin Miaolin Feng Jie Dong National Engineering Research Center of Light Alloy Net Forming & State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Department of Engineering Mechanics Shanghai Jiao Tong University

Plastic deformation up to final rupture failure of a rolled magnesium（Mg） alloy Mg-3.0Al-1.0Zn-0.34Mn（AZ31B） under low stress triaxiality was *** strain evolution was quantified by the digital image correlation（DIC） technique analysis with tensile,combined tensile-shear,and shear specimens,corresponding to the stress triaxiality of 1/3,1/6 and 0,***-strain curves show that the yield stress reduces with the decrease in the stress triaxiality,and obviously exhibits different strain hardening *** backscatter diffraction（EBSD） observations reveal that the twinning behavior depends on stress *** fracture,double twinning is the dominant mechanism at the stress triaxiality of 1/3,while extension twinning is prevalent at the stress triaxiality of ***,scanning electron microscopy（SEM） shows that the fracture mechanism is transformed from microvoid growth and coalescence to internal void shearing as the stress triaxiality decreases from 1/3 to 0.

关键词： Magnesium alloy Stress triaxiality Twinning

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A Review on Particle Reinforced Mg Matrix Composites Fabricated by Powder Metallurgy

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 391-400页

作者： Zhiyuan Liu Li Jin Jian Zeng Fulin wang fenghua wang Shuai Dong Jie Dong National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composite School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

This paper provides a comprehensive review of research progress in particle-reinforced Mg matrix composites prepared via powder *** article discusses different strategies,such as micro-sized,nano-sized particles,and multi-particle hybridization,which has been employed to enhance the performance of the *** addition,a range of preparation techniques that optimize the dispersion of the reinforcing particles are *** paper also highlights how the different configurations between the reinforcements and matrix alloy impact the composites’***,the article outlines the prospects of particles reinforced Mg matrix composites fabricated via powder metallurgy and recommends modification methods that could be explored to further develop these materials for various applications.

关键词： Magnesium matrix composites Reinforcing particle Powder metallurgy Mechanical properties Configuration

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Effects of holding time and Zener-Hollomon parameters on deformation behavior of cast Mg-8Gd-3Y alloy during double-pass hot compression

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Journal of Materials Science & Technology 2018年第11期34卷 2035-2041页

作者： Xi Nie Shuai Dong fenghua wang Li Jin Jie Dong National Engineering Research Center of Light Alloy Net Forming School of Material Sciences and EngineeringShanghai Jiao Tong University

Double-pass hot compression tests were carried out over a wide range of holding time（0–180 s） and Zener-Hollomon parameter（1.6 E15–1.3 E20） to study the deformation behavior of cast Mg-8 Gd-3 Y *** flow curves show obvious work hardening and strain softening stages, leading to the peak stress of double-pass hot compression. Holding time and Zener-Hollomon parameter can significantly affect the second pass peak stress. It is found that increasing the holding time can cause a higher peak stress in the second pass deformation. The second pass stress reaches the peak stress of 71 MPa at ZenerHollomom parameter of 1.6 E15. When the parameter rises to 1.3 E20, the second pass peak goes up to237 MPa. In addition, the second pass peak stress is significantly higher than the unloading stress, which is opposite to the flow behavior of aluminum alloys. Residual stored deformation energy caused by the first pass deformation could be consumed by metadynamic recrystallization. Therefore, more strain energy is required for subsequent dynamic recrystallization, resulting in hardening behavior. A hardening fraction is defined to describe the deformation behavior quantitatively, which shows a positive correlation with the metadynamic recrystallization fraction. The metadynamic recrystallization leads to grain growth at the inter pass holding stage, diminishing dynamic recrystallization nucleation positions in the second pass deformation.

关键词： Mg-8Gd-3Y magnesium alloy Double pass hot compression Deformation behavior Metadynamic recrystallization

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Simultaneously improving strength and ductility through laminate structure design in Mg–8.0Gd–3.0Y-0.5Zr alloys

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Journal of Materials Science & Technology 2021年第12期71卷 195-200页

作者： Jing Li Mengjie Zhao Li Jin fenghua wang Shuai Dong Jie Dong National Engineering Research Center of Light Alloy Net Forming&State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China

The laminate structure was applied to improve the mechanical properties of Mg-8.0 Gd-3.0 Y-0.5 Zr *** types of laminate structures only with different distribution positions of fine grains were produced by friction-stir *** show that the trilayer structure sample exhibits an excellent strengthductility synergy compared to the homogenous structure and bilayer *** enhanced mechanical properties are resulted from the hetero-deformation induced(HDI)stress strengthening and strain hardening which would be enhanced by increasing the quantity of *** observations suggest a crucial role of the number of interfaces in designing the laminate structure.

关键词： Friction-stir processing Mg-Gd-Y-Zr alloy Laminate structure Interface Strength-ductility synergy

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