基于EtherCAT的自动焊接控制系统研究

针对散热器管板焊接存在劳动强度大、焊缝一致性差,产品合格率低等问题,设计以Ether CAT技术为基础的多轴焊接自动控制系统,该系统以德国BECKHOFF公司Twin CAT+工业PC作为主控制器。对Ether CAT技术原理进行了介绍,给出控制方案,包括机械台架构造、软硬件平台搭建、主程序流程等。描述了伺服驱动Fuzzy-PID控制算法和系统调试步骤。通过调试运行,结果表明:该焊接控制系统具有较好的实时性、同步性和鲁棒性,抗干扰能力强,满足散热器管板焊接要求,为散热器管板焊接提供了一种新途径。     

电阻炉的温度控制系统

针对电阻炉的特点,介绍单片机温度控制系统的软、硬件.该系统以8098单片机为核心,采用Fuzzy-PID控制算法组成炉温控制系统.     

双缸同步液压系统Fuzzy-PID控制仿真研究

针对液压同步系统仿真大多没有考虑摩擦阻力不等、两缸负载不均衡以及变负载等因素对同步精度造成的影响,利用AMESim软件进行建模,并在Matlab/Simulink中建立积分分离式PID以及Fuzzy-PID控制算法来实现液压缸的同步起竖以及曲线同步跟踪.仿真结果表明,采用Fuzzy-PID控制算法,系统实现较高精度的同步控制.提出的双缸同步控制策略对其他设备中液压同步控制系统的设计研究也有很好的参考价值.     

RoboCup中型组足球机器人运动控制系统的设计

以RoboCup中型组足球机器人为研究时象,以提高机器人足球平台硬件系统性能为目标,设计了一种基于双DSP架构并结合Fuzzy-PID控制算法的足球机器人。实验结果表明,该控制系统对足球机器人的运动性能、控制精度、实时性都有了极大的改善,能满足全自主足球机器人的运动控制的要求。     

基于LabVIEW的盾构推进系统模糊PID控制

介绍了盾构推进液压系统的工作原理,并建立了推进液压缸的数学模型。利用LabVIEW提供的模糊逻辑工具箱设计了一种Fuzzy-PID控制算法。以LabVIEW为仿真平台,分别采用常规PID和模糊PID对系统进行了仿真分析,仿真结果表明该Fuzzy-PID控制器具有较强的抗干扰能力和鲁棒性,有较好的动、静控制精度。     

模糊PID在电阻炉温度控制系统中的应用

针对电阻炉的特点,提出Fuzzy-PID控制算法,介绍了模糊PID控制器原理,并改进了Fuzzy-PID控制器算法.仿真实验表明该控制系统的特性得以改善.     

Fuzzy-PID在反重力铸造液面加压控制系统中的应用

由于反重力铸造过程的时滞性、不确定性、复杂性,难以建立精确的数学模型。因此采用不依赖于数学模型的PID控制算法,而传统PID存在动态性能差、稳定恢复时间长、容易出现超调的缺点。为了实现对复杂系统的精确控制,引入Fuzzy控制,将二者结合起来,设计了Fuzzy-PID混合控制算法。该控制算法继承了PID控制无静差、静态性能好的特点,同时又兼有Fuzzy控制适应能力强,动态性能好的优势。实践证明,该控制算法对参数变化适应性好,抗干扰能力强,适合应用在反重力铸造液面加压控制系统中,并取得了良好的控制效果。     

基于云模型的铝合金缸盖金属型铸造过程温度控制

针对铝合金发动机缸盖产品质量一致性差的问题,建立金属型铸造凝固过程数学模型,得出其具有非线性、强耦合性以及不确定性等特点,利用云模型能够实现定性定量之间的不确定性转换的特点,与PID控制方法相结合,以实现凝固过程最优温度控制。为验证控制算法的优越性,建立温度控制系统试验平台并对人工操作、PID控制以及云模型PID控制算法做对比试验。结果表明,云模型PID具有更良好的跟随能力以及更高的稳定性。     

基于Fuzzy-PID控制的二辊轧机控制系统

本文阐述了Fuzzy-PID控制方案在张家口铝制品厂的应用，详细分析了Fuzzy-PID控制算法，并论证了它的可行性和优越性。     

基于Fuzzy—PID的铸件时效炉分布式控制系统

根据铸件时效炉时效工艺与控制特点以及基本设备组成,设计与开发了铸件时效炉分布式控制系统.系统软件核心部分是调节单元的算法设计.将Fuzzy控制与PID控制算法相结合,发挥两种控制方式的优点,构建了铸件时效炉分布式控制系统调节单元Fuzzy-PID复合控制策略.生产实践表明,此系统一定程度上改变了时效炉以往控制过程中呈现出的温差大、能耗多、时效质量差的落后状况.     

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。