伺服电机控制系统调试平台设计与开发

针对伺服电机控制系统设计调试时,仿真误差大、试验周期长的问题,基于电机实物设计开发了可以实现快速调试控制系统参数的硬件平台;基于Arduino控制板设计了伺服电机PID调速控制系统。该平台可与计算机连接进行实时参数调试,并在平台显示器上显示控制参数与转速。经试验验证,结果表明调试后的程序可以较好地满足实际所需,同时验证了该实验平台可以有效地用于直流伺服电机控制系统设计及调试,提高调试效率,降低开发成本。     

基于Labview的电火花自动沉积监控系统设计

电火花沉积可制备硬度高、耐磨性和耐腐蚀性优异的强化涂层,能显著提高机械零部件的性能和使用寿命,传统电火花沉积主要依靠人工操作.基于Labview开发平台设计了一套电火花自动沉积监控系统,其硬件主要由PC机、Arduino控制卡、步进电机等组成,该系统具有运动控制、运动反馈、数据采集、沉积轨迹设置和显示等功能,并在沉积路...     

激光视觉焊缝跟踪系统设计与关键技术

设计了一种具有较好应用前景的激光视觉焊缝跟踪系统,该系统基于DSP图像处理平台,采用焊接行业常用PLC工业可编程控制器、工业触摸屏等模块,具有焊缝图像实时显示单元。其总体成本较低,功能完善,可独立控制焊炬运动,检测速度快,易于与焊接领域其他控制系统直连。通过改进的激光器电源调节与滤波电路设计,解决了焊接现场电磁干扰影响激光器寿命问题;从CCD成像原理,推导出影响焊缝跟踪中CCD标定的关键因素,设计了CCD自适应标定方法,提高了系统的检测准确度;跟踪试验表明,本系统软硬件设计合理,有效地防止了焊接现场较强的弧光干扰,跟踪过程平稳,满足焊接自动化发展需要。     

光纤激光器激光-TIG复合焊接工艺

对光纤激光器激光与TIG复合焊接工艺进行了研究,并通过一套光纤激光器对激光与TIG复合焊接系统进行了相关试验,考察了光纤激光器激光与TIG复合条件下焊缝外观、熔深、对间隙的适应性等。结果表明,复合条件下焊缝外观、熔深、对间隙的适应性等相对激光焊接都有所提升。     

小型化低功率教学用激光热处理实验平台的研究

针对目前激光热处理教学实验平台的研发不足,采用低功率的光纤激光器,搭建一个能耗和成本低的用于教学及科研的激光热处理小型平台,满足教学和科研的实验要求,并选用45钢在该平台上完成激光淬火实验,同时分析了淬火时间和相对离焦量对淬火后硬度的影响。结果表明:激光淬火后,表面硬度提高到原先的2倍。经多次实验并调整参数,实验结果验证了该实验平台的可靠性和使用性。     

激光热处理装置与工艺

近年来国内外都在大力发展用激光进行制件的表面热处理。激光加热与其它形式的加热相比,具有如下主要优点:能量高度集中;可以局部强化和处理难以达到的部位;零件不会翘曲和变形;可以把辐射能传递到很远距离(100米以内)。此外,激光热处理还不需要使用淬火介质。使用现代化水平的工艺激光装置,可保证热处理过程实现实际上的全部机械化与自动化,从而可在根本上提高劳功生产率,改善辅助人员的劳动条件。大功率激光器,按工作制度可分为以一次发光或连续发光照射的脉冲式激光器和在长时间内照射的连续式激光器。     

不同类型激光器对激光多层沉积Ti-35V-15Cr合金显微组织及性能的影响

目的 探讨半导体激光器与CO2激光器对激光多层沉积合金显微组织及性能的影响机理。方法 以充分混合的Ti、V、Cr粉末为原料,于预先打磨后的Ti-6Al-4V基板上使用CO2和半导体两种激光器进行激光多层沉积Ti-35V-15Cr,通过光学显微镜和扫描电镜、激光点火法、显微硬度测试和Jmat-Pro软件计算分别评价不同激光器下沉积试样的显微组织特点、抗阻燃性能对比和组织形成机理分析。结果 半导体激光器与CO2激光器沉积的试样显微组织存在很大差别,前者为全等轴组织,等轴晶平均尺寸为100 μm,晶粒大小与形状基本一致,沉积区与基材之间的过渡区域存在平均宽度为200 µm、长度为526 µm、长宽比为2.6的类等轴晶,通过扫描电镜观察发现在部分等轴晶内部存在亚晶结构;后者主要为平均尺寸120~200 µm的柱状晶组织,沉积试样顶部为平均直径为52 µm的细小等轴晶,通过扫描电镜观察发现枝晶偏析组织,枝晶间的距离为5~10 µm。抗阻燃性方面,半导体激光器制备的Ti-35V-15Cr试样的抗阻燃性能略优于CO2激光器制备的Ti-35V-15Cr试样,平均显微硬度前者为375HV,后者为363HV。结论 由于激光多层沉积Ti-35V-15Cr对半导体激光器与CO2激光器产生的激光吸收率不同而使二者形成完全不同的显微组织,由半导体激光器制备的Ti-35V-15Cr试样显微硬度更高、抗阻燃性能更好。     

微型自动循迹搬运车控制系统的开发

为了探究复杂路径多点搬运的问题,开发了基于Arduino控制器的微型循迹搬运车控制系统。对系统硬件和系统软件进行了研究,系统硬件包含控制器、驱动元件和检测元件等,系统软件按功能将其分成循迹模块、颜色识别模块和串口通信模块等。提出了采用Arduino Nano和串口通信对小车进行控制,以实现循迹校正、红外寻标、自动搬运等功能。通过现场调试,该系统能控制自动搬运小车在铺设的轨迹上对不同颜色的物体进行循迹搬运,并根据颜色的不同将其放置在指定位置。     

Arduino与MATLAB混合模式人机对弈系统设计方法

为了解决人机对弈系统的程序可读性差、研究效率低及开发周期较长问题,提出一种具有高可读性、高效率、高精度的人机对弈机器人系统设计方法。通过对弈过程及博弈行为分析,确定人机对弈系统的功能及组成,并详细叙述软件系统设计以及利用Arduino与MATLAB混合编程设计方法。最终,利用博弈试验证明,在保证控制执行效率和精准度的前提下,此方法程序可读性及移植性明显提高。该设计方法不仅为后续系统开发奠定了良好的实践基础,而且为人机对弈系统开发提供一种新模式。     

微孔节流气体静压止推轴承跨缝过程时变特性研究

目前,大型气浮平台均采用花岗岩平台拼接而成,平台拼缝会对实验效果产生一定影响。针对上述问题,以微孔节流气体静压轴承运动中经过平台拼缝时的时变特性为研究对象,建立微孔节流止推轴承物理模型,并使用CFD软件与UDF相结合的动网格技术实现轴承跨越平台拼缝的动态过程仿真,研究不同气膜厚度、进气口压力、平台拼缝位置对轴承承载力和压力分布的影响。结果表明：当平台拼缝到达微孔分布圆附近时承载力急速下降,且平台拼缝到达轴承中心时承载力下降到最小值;随着气膜厚度的增加,轴承承载力的最大损失比例随之增加,并最终稳定到0.6;平台拼缝位于供气孔分布圆之外时,轴承边缘与平台拼缝之间的承载面将失效;通过增加进气口压力,轴承承载力整体有明显提升,但承载力损失速度也明显加快。     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

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.