基于CAN总线的三轴数控系统设计

提出了一种伺服系统分布式控制方案,数控装置和伺服电机驱动器之间采用CAN总线连接,构成现场级的分布式运动控制网络,以实时通讯方式代替传统的并行模拟/脉冲信号,实现伺服系统的闭环控制。文章首先对CAN总线的伺服电机驱动器设计、CAN总线运动控制卡设计等关键问题进行了比较详细的论述,然后将该系统用于高速模具雕刻机进行实验。实验结果证明该系统具有良好的运动控制性能,运行速度、轮廓控制精度和定位误差均达到模具雕刻机设计要求。     

基于CAN总线的分布式交流伺服系统研究与设计

随着计算机技术的发展,运动控制系统正向着分布式控制方向发展.本文在分析运动控制系统的发展现状与要求的基础上,提出了一种基于CAN总线的分布式交流伺服系统实验平台的设计方案,并详细分析了系统的硬件接线与软件的设计方法.该设计已成功地应用在实验系统中,该系统具有连接简单、通讯可靠、实时性好和易于实现等优点.     

以太网与CAN总线互联网关的设计

目前,现场总线在工业企业中得到了广泛应用,并对现在的工业控制领域产生了深远的影响.但是现场总线难以实现与因特网的互联.以太网是目前最流行的现场总线接入因特网的方案之一,它在发挥现场总线优点的同时解决了现场总线难以接入因特网的问题.文章以实现CAN现场总线接入因特网为目标,在对CAN协议及TCP/IP协议进行深入研究的基础上,设计了以太网与CAN总线互联网关,从而实现以太网与CAN总线的互联,为实现企业信息网络与控制网络集成提供了一种可行的方法.     

基于CAN总线的分布式伺服系统通信协议的研究

提出了一种基于CAN总线的分布式伺服运动控制方案,针对数控系统对多轴运动控制严格的同步要求,设计了一种“分时通信、同步执行”协议模型,有效地降低了同步运动控制对现场总线带宽的依赖。文章对分布式运动控制的网络拓扑结构、数据通信和运动同步协议模型、数据帧格式以及通信的实时性等关键技术问题进行了比较详细的论述。最后将上述协议模型用于CAN总线分布式三轴数控系统进行实验,结果证明该系统在通信实时性和运动同步控制方面具有良好的性能。     

基于CAN总线多轴伺服电机的同步控制

研究CAN总线在多轴运动控制系统中的应用。构建基于CAN总线的多轴交流伺服运动控制系统,通过CAN总线进行数据的传输与控制,可以使伺服电机的性能更加稳定,实现多轴伺服电机的同步控制。     

基于CO2焊接系统的CAN总线设计

针对CAN总线技术在数据传输中具有实时性和灵活性等特点,并能构成分布式系统可靠性高和成本低等优点,设计了以CAN总线为通信,以ARM为控制芯片的数字化CO2焊接电源系统.编程实现了整个焊接系统的数字化控制.详细说明了CAN总线电路的设计、CAN总线的通信协议设计.对实现焊接系统的智能化控制具有一定的指导作用.     

基于CAN总线的分布式数控系统研究与实现

针对目前实时数控系统的发展现状和存在问题,提出了一种基于CAN总线的运动控制平台,该平台由高性能DSP芯片构成的伺服控制模块和嵌入式计算机模块两部分组成.本文介绍了该运动控制平台的分布式控制策略和构建实时数控系统的方法,介绍了其软硬件结构和系统的具体实现过程.该研究成果广泛应用于机器人、高精度数控机床等运动控制系统.     

基于CAN总线的网络监控模块化柔性生产线

通过CAN总线将控制层系统组网,利用以太网实现数据共享,从而实现网络监控的柔性生产线.着重讨论了柔性生产线的柔性化以及柔性生产线的结构系统,设计开发了基于CAN总线模块的柔性生产线单元控制器,实现了功能模块化和程序模块化,使得柔性线的组合和功能的实现更加灵活、便利,现场布线更加简洁、方便.并且提出了网络监控系统中各个子系统即控制层和网络监控层系统的网络结构的组网方案,最终实现了网络监控系统的柔性生产线功能.     

基于FPGA的网络型运动控制芯片设计

针对运动控制系统网络化、集成化的需求,提出了一款基于FPGA的网络型运动控制芯片设计方案.在单片FPGA中实现了以太网网络芯片的控制、数据协议解析、运动控制精插补器和编码器反馈接口,与上位机、网络主站构成运动控制网络,可以驱动步进电机、位置模式伺服驱动器,实现高效集成的网络化运动控制,适合在多通道复合数控机床、多轴运动控制等场合应用.仿真与实验验证了方案的可行性.     

数字化焊机的CAN总线系统研究

针对焊接行业发展热点之一的控制网络化和信息化,介绍了一种基于CAN总线的数字化焊接网络控制系统。通过CAN总线将数字化焊接设备组成网络,基于CAN2.0B规范,制定了简单实用的通信协议。详细介绍了协议的制定、报文发送流程和应用实验测试,为焊接设备控制的网络化和信息化发展提供了一个良好的平台。     

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.     

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.