一种飞机液压阻尼器动态试验系统的设计与实现

对液压阻尼器动态试验测控系统进行了研究;对试验台测控系统构成及原理进行了分析介绍;提出了由上下位机组成的测控系统方案;下位机以TMS320F2812为核心,控制永磁同步电机驱动液压阻尼器,上位机为工业控制计算机,采集监控液压阻尼器动态数据,采用零相位滤波器对数据进行处理。结果表明:液压阻尼器动态试验台各项指标均达到设计要求。     

基于AD7606的焊接电弧电信号高精度数据采集系统设计

焊接电弧电信号可用于焊接过程控制和焊接质量评定,而电弧电信号数据采集的精度和实时性会对后续信号的分析、处理等产生重要的影响。设计了一种以AD7606为模数转换器,DSP TMS320F2812芯片为运算及控制核心的焊接电弧电信号高精度数据采集系统,分别介绍了霍尔传感电路、系统接口电路的设计以及数据采集处理的软件实现。试验结果表明,该数据采集系统精度高、实时性强,能够满足对焊接电弧电信号的分析和处理要求。     

基于CAN总线的GMAW焊机网络监控系统

采用CAN总线实现GMAW焊接电源、行走机构及遥控盒间的网络连接,并连接到上位机,方便实现焊接过程质量监控.介绍了采用TMS320F2812内嵌eCAN模块构成CAN节点的硬件电路和实现CAN通信的软件流程.实践证明,CAN总线应用于GMAW焊机的网络监控系统,能够实现数据的可靠传输.     

数字化大功率微弧氧化电源控制系统

介绍了一种数字化多自由度大功率微弧氧化电源的控制系统,该电源控制系统以TMS320F2812为控制核心,用S3C2410控制的触摸屏作为系统的人机界面.详细说明了该电源主电路结构、控制系统硬件和软件设计流程以及人机界面设计.研制出的微弧氧化电源控制系统具有恒压、恒流以及恒功率三种工作模式,每种工作模式下可以按照上位机的...     

基于TMS320F2812的RS485通信系统设计

基于工业自动化控制对于上下位数据传输所需的实时性与数据可靠性需求,设计了一套基于TMS230F2812型DSP芯片的RS485数据通信系统。论述了RS485的通信原理及该系统利用DSP内嵌的485A中断模块实现与上位机实时通信的工作流程与软件设计。测试表明,该系统数据传输稳定,通信速率高,抗干扰能力强,对工业自动化设备的数据通信起到了良好的效果。     

基于DSP和3G的风电增速箱故障监测系统研究

以风力发电机的增速箱为研究对象,选用TMS320F28335数字信号处理器(DSP)和3G无线通信模块EM820W搭建硬件平台,设计一种嵌入式的在线实时故障监测系统。该系统利用DSP实现对风电增速箱的数据采集、存储和数据信号的分析等功能,而EM820W无线通信模块则实现数据的无线通信传输功能,将DSP分析的结果和采集的原始数据传送到上位机,从而实现对风电增速箱的远程在线诊断与监测功能,监测增速箱的工作状况。     

基于积分分离单神经元PID的联网送丝机控制研究

对送丝速度精确稳定的控制是自动焊机焊接质量的重要保障,提高送丝系统性能的主要途径是改善硬件系统性能和控制算法.利用TMS320F2812的QEP模块可以直接接收正交脉冲信号的特性,能够提高硬件系统的响应速度,也简化了硬件电路.采用积分分离的单神经元PID算法对送丝速度进行数字化控制,相对于传统PID算法具有更好的稳态和暂态特性,且遗传特性和简易程度更优于流行的模糊PI控制,配合总线连接上位机,更易于实现在线控制和送丝系统的全面数字化.     

基于TMS320F2808异步电机直接转矩控制系统的硬件实现

本文搭建了以TMS320F2808为控制核心的异步电机直接转矩控制系统硬件平台,完成了直接转矩控制系统硬件设计,并给出了电流、电压检测电路。该系统克服了采用TMS320F2407A和TMS320F2812 DSP作为直接转矩控制系统的控制器所存在的诸多不足,具有良好的通用性和兼容性、抗干扰能力强、体积小等特点。     

磁旋转编码器在高速电主轴控制系统中的应用

iC-MH磁性编码器是德国iC-Haus GmbH公司生产的一款针对极小空间的快速12位编码器,选用该传感器与TMS320F2812控制板,通过合理设计其接口电路并使用BiSS串口通讯协议对iC-MH编码器进行初始化设置,实现了高分辨率、高速度的位置测量系统并在高速电主轴控制系统中成功应用.     

基于TMS320F28335 DSP的三相电动机控制器的设计

以浮点型DSP TMS320F28335为核心开发三相电动机控制器。该DSP与TMS320F2407和TMS320F2812相比具有速度快、精度高等优点,更适合复杂算法的需要。详细介绍各个功能部分的工作原理及硬件实现方法。该系统既可以采用旋转编码器进行速度反馈又可以采用无速度传感器方式工作。实践证明:该控制器运行可靠,工作稳定。     

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.