超声电机位移分辨率特性研究

超声电机作为一种新型特种电机,有着广泛的应用。由于超声电机应用压电陶瓷作为驱动元件,使得定子产生受迫振动驱动动子运动,从理论上具有高的位置分辨率,为了确定超声电机的位移分辨率,文章从超声电机运行机理出发,分析了影响超声电机位置分辨率的因素为定子/转子摩擦材料系统的瞬态响应。应用单片机作为控制器,通过程序控制超声电机驱动器,测试了旋转型行波超声电机的位置分辨率,得到旋转型超声电机的位置分辨率可以达到0.0078°。得到结论:得到了超声电机分辨率,且发现超声电机定子/转子摩擦材料系统的阻尼是影响超声电机位移分辨率的关键因素之一,超声电机定子和转子摩擦材料系统非线性特性明显。     

焊接系统中参数显示的数字控制设计

为了克服焊接系统中模拟控制带来的困难,介绍了一种自动埋弧焊数字控制系统参数显示的设计方法,该设计方法适用于各种焊接系统中行走电机速度、送丝电机速度和系统其他数据的显示。控制系统以DSP为中央处理器,以ARM作为系统专用液晶显示芯片,控制器之间通过串行接口交换数据。由ARM芯片处理焊接系统数据的设置、显示、记忆和管理,使埋弧焊机成为一个真正的智能焊接系统。     

基于ARM的焊接机器人示教控制系统设计

设计了一种基于ARM的焊接机器人示教控制系统,介绍了该控制系统的硬件电路组成与软件实现流程。以ARM11系列S3C6410为主控芯片,在该核心控制器上扩展了CAN2.0通讯接口以及RS232通讯接口,通过CAN2.0与步进电机控制器通讯实现XYZ-R轴运动控制。使用MFC智能设备应用程序创建相关按钮控件、编辑控件设计人机交互界面。控制系统的人机交互界面、操作界面简单实用。采用val语言制定再现编程指令,可对焊缝轨迹进行焊接示教。通过搭建焊接仿真实验平台,进行示教再现测试实验,证明该控制系统能满足复杂的焊缝轨迹的焊接,同时该操作系统操作简便,性能稳定。     

基于ARM的磁浮轴承控制器的设计

设计了一种基于ARM的磁浮轴承控制器,该控制器能够控制5个维度使转子悬浮,同时能够及时调整10组电流驱动器。该控制器选用32位ARM STM32F401RC作为核心处理芯片,具有可靠性高,速度快的优点.运行结果表明:精度能够达到0.05 mm,运行稳定可靠。     

基于STM32F407VE的磁浮轴承控制器的设计（英文）

为了对传统磁浮轴承控制器的不足之处进行改进,设计了一种基于ARM的磁浮轴承控制器。该控制器能够控制5个维度使转子悬浮,同时能够及时调整10组电流驱动器。该控制器选用32位ARM STM32F407VE作为核心处理芯片,具有可靠性高,速度快的优点,精度能够达到0. 02 mm,运行稳定可靠。     

可编程控制器在电机保护中的应用

采用以计数器为核心元件的可编程控制器对电机实行保护、不仅具有结构简单、应用灵活、灵敏度高、可靠性好、响应快的特点，而且还有数码显示程序执行状态之功能，维修方便。本文介绍了可编程控制器的工作原理及应用方法。     

基于STM32F407VE的磁浮轴承控制器的设计

为了对传统磁浮轴承控制器的不足之处进行改进，设计了一种基于ARM的磁浮轴承控制器。该控制器能够控制5个维度使转子悬浮，同时能够及时调整10组电流驱动器。该控制器选用32位ARM STM32F407VE作为核心处理芯片，具有可靠性高，速度快的优点，精度能够达到0.02 mm，运行稳定可靠。     

直线型超声电机在机床进给系统中的应用

文章简要比较了直线电机驱动和传统滚珠丝杠机床进给驱动的优缺点及直线电磁电机存在的问题;详细介绍了直线超声电机的运动机理,直线型超声电机相对于电磁式直线电机的优点和直线型超声电机的国内外发展和研究现状;并综述了直线型超声电机在机床进给系统中的应用研究现状.     

用于嵌入系统的超声电机驱动设计

为了在嵌入式控制系统中充分利用超声电机特有功能,对超声电机的驱动原理进行了研究,在分析了超声电机的驱动控制原理的基础上,提出了一种基于单片机控制超声电机的软硬件控制实现方法。利用单片机输出数字量作为控制信号,通过串行输入并行输出芯片扩展后,输出到超声电机驱动器,实现超声电机启动/停止/正反转的功能;通过扩展单片机数模转换,将单片机控制超声电机速度的数字信号转换为电压信号,实现超声电机的速度控制功能;利用运行脉冲宽度控制实现超声电机的位置控制功能,并将光电编码器实现超声电机的反馈,最后通过试验验证了单片机系统实现超声电机驱动设计。     

数控系统中RS485串行通信协议的设计

文章设计并实现了一种适用于ARM与DSP之间串行通信的通信协议,采用RS-485总线标准,硬件接口简便,通信可靠性高,并讨论了其软硬件的实现,可用于数控系统中.最后在ARM作为主控制器,DSP和FPGA作为从控制器的数控系统中验证了该协议在串行通信中的可靠性.     

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。