平面线圈型直线时栅参数优化方法的研究（英文）

提出了一种基于非线性规划遗传算法的平面线圈型直线时栅位移传感器结构参数的优化方法,与传统枚举法相比该方法在优化效率和效果上都有大幅度的提高。通过建立基于非线性规划遗传算法的数学模型对传感器参数进行优化,根据优化结果建立传感器物理模型进行仿真,并设计传感器样机进行实验。与枚举法优化结果相比较:优化效率提高了65%,谐波畸变率降低了10倍。在240 mm的量程范围内,测量精度达到0. 8μm。结果表明了该优化方法的可行性,优化后的传感器从结构上抑制了原始误差,实现了高精度测量。     

视觉测量在机器人加工过程手眼标定中的应用

针对高精度测量辅助机器人加工的手眼标定,提出一种基于三维视觉测量的精确手眼标定方法,该方法考虑了非线性优化和初值计算中建模误差的影响。为了提高求解精度,在传感器框架中建立了具有更精确参考点的非线性标定模型,提出一种结合传感器测量和机器人位置随机误差的迭代权重优化解。在初值解中,建立考虑基础参考测量误差的测量平差模型,并使用拉格朗日乘子进行求解。仿真对比结果表明：该方法在估计手眼变换参数方面比其他典型方法具有更高的精度。最后通过搭建实验平台,进一步验证了所提方法在求解精度测试上的优越性。     

基于神经网络和粒子群算法的切削参数现场实时优化

为了使金属切削加工中，能实现切削参数的实时优化，保证产品质量和设备效率，提出了一种新的切削参数最优化方法，引入加工时间、加工精度、加工成本三个目标控制量，建立了多目标非线性规划模型。并用惩罚函数法将多目标非线性约束规划问题转换成无约束非线性单目标规划问题。通过对神经网络和粒子群算法的有机结合，并充分利用了粒子群算法和BP网络各自具有的优点，对模型进行了求解。数值试验表明该方法能较好地解决切削参数的优化问题。     

基于遗传算法的位置PID控制器在旋转TIG焊接系统中的应用

设计了一种基于遗传算法的参数整定PID控制器,该控制器首先将PID参数整定转化为求解优化问题,进而应用遗传算法求出优化问题的解。将该种控制器应用在基于旋转电弧传感器的TIG焊焊接系统中,为了加快搜寻速度,提高求得最优解的概率,对选取和淘汰策略方面进行了改进。试验表明,基于遗传算法的参数整定PID控制器改善了TIG焊的实时跟踪性能,提高了焊接质量。     

基于BP神经网络的强力旋压成形连杆衬套壁厚预测

对不同工艺参数组合的连杆衬套的强力旋压成形过程进行了模拟,基于BP神经网络技术,建立了工艺参数与壁厚之间的非线性函数关系。用模拟实验结果训练神经网络模型,以实现对连杆衬套壁厚的预测。该方法不仅可以缩短工艺参数优化的时间,而且能够有效地提高连杆衬套工艺设计的效率。     

基于BP神经网络遗传算法的薄板CMT点焊变形

焊接是汽车车身制造的一个关键环节,焊接质量的好坏严重影响汽车车身质量,所以焊接参数的选择至关重要. 针对薄板焊接质量控制问题,论文利用BP神经网络解决非线性问题的优势,建立焊接变形量与工艺参数之间映射关系模型;结合遗传算法构建基于遗传神经网络焊接的工艺参数优化系统;同时设计正交试验,将该方法与正交试验法相对比. 结果表明,该方法可以有效地实现CMT(cold metal transfer)点焊焊接变形预测与工艺参数优化. 通过预测模型给出合理参数,指导钢薄板和铝合金薄板的CMT点焊变形试验,提高焊接的效率.     

方锥件渐进成形工艺优化

针对渐进成形中板料严重减薄、易开裂和尺寸精度差及成形效率低等问题,采用BP神经网络建立了优化目标和工艺参数之间的非线性映射关系。然后利用多目标遗传算法(NSGA-II)实现方锥件渐进成形工艺参数的优化。结果表明,采用BP神经网络与多目标遗传算法能很好地优化渐进成形工艺参数,提高零件成形质量。     

基于改进灰狼算法优化SVM的机器人坡口类型识别

基于双目视觉传感器的机器人移动平台建立图像采集系统，研究了一种改进的灰狼算法和最小化参数策略结合，来优化支持向量机，实现对不同焊缝类型进行识别。首先，在灰狼算法中引入佳点集理论生成初始种群，减少灰狼种群种类数，为算法全局搜索的快捷和稳定性奠定基础。然后，在分类器SVM中引入非线性收敛因子，并结合最小化参数的策略，加强最优参数的泛化能力。最后，通过基于最优参数建立的SVM模型进行焊缝类型识别试验。证明了改进算法优化的SVM模型相对于粒子群算法、遗传算法、布谷鸟算法和基本灰狼算法，在识别准确率和优化速度方面都有了较大的提升。     

基于改进遗传算法的数控机床加工铣削参数优化方法

对于数控机床加工铣削参数优化多采用常规的可信度近似模型,但该方法易受到材料失效应变系数的影响,导致优化后的加工效率较低,提出基于改进遗传算法的数控机床加工铣削参数优化方法。根据工件的本构模型,对切削刃进行采样抽取,确定最小铣削力波动位置;引入材料失效准则计算材料失效应变系数,基于此,以加工时间最短、加工成本最低和加工能耗消耗最小为目标建立铣削参数优化模型,并采用改进遗传算法求解模型,通过迭代适应度值,输出最佳铣削参数;最后,采用对比实验的形式对所提方法的优化性能进行测试。测试结果表明：应用所提方法对数控机床加工铣削参数进行优化后,能够有效缩短切削时间,提高加工效率。     

混合遗传算法优化的等离子切割机弧压调高控制研究

文章针对数控等离子切割机弧压调高系统由于电机非线性、负载扰动影响难以获得最佳控制参数的问题,分析系统的特征和控制需求,提出了基于混合遗传算法的切割机弧压调高系统控制方法,该方法通过遗传算法对系统PID参数进行全局优化,并利用成长算子改进标准遗传算法框架,增强遗传算法优化的快速性以进一步进行最佳参数辨识.结果显示,混合遗传算法优化应用于等离子切割弧压调高控制中切割质量显著提高,具有良好的工程应用价值.     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。