并联水泥装载机器人运动学研究

针对当今水泥装载行业的实际需要,提出一种自动水泥装载机器人,并设计开发出一种结构简单、驱动部件少、控制简单的并联水泥搬运机器手。介绍了该机器人的整体结构方案,确定该机器人的可行性与实用性。介绍了并联搬运机械手的基本结构组成并计算自由度,验证了该机构运动的确定性,并建立了运动学数学模型,得出其位置、速度及加速度的运动学逆解解析形式。通过运动学分析,为驱动机械手的伺服电机合理选型及机构的设计和进一步优化提供了参考。     

基于PLC的液压搬运机械手设计

介绍了一种应用于加工生产线的搬运机械手.根据用途分析了机械手的动作循环及工作原理,设计了机械手的结构、液压系统及PLC控制电路.该机械手结构简单,运行平稳,精度满足工作要求,其液压系统和PLC控制系统简单可靠.     

用于方形物件装卸液压机械手的设计

设计一种用于方形物件装卸的液压机械手,主要介绍该机械手的工作原理、总体结构及液压控制系统,重点介绍其手部夹持结构和回转结构。这种机械手主要用于方形物件的装卸,动作灵活,安全可靠,易于调节和控制,操作简单,便于实现堆码机械自动化。     

凸轮轴机床的工件输送机械手的研制

介绍了在七工位凸轮轴加工机床上应用的机械手,该机械手用于实现工件的输送。详细论述了机械手的功能、技术参数、工作原理、主要结构及特点。该机械手为液压驱动的圆柱坐标型搬运装置,其结构简单、抓取重量大、开合行程长、运行可靠,大大提高了生产效率。     

带平转功能的发动机缸体抓取机械手

文章介绍了为发动机缸体自动生产线设计的一种能够自动上下料并带有平转功能的机械手。对发动机缸体毛坯结构特点、输送运动状态等进行了较深入的分析。机械手采用发动机缸体缸孔及顶面定位,液压驱动,并通过PLC控制其整个动作过程。同时对机械手整体结构、控制系统和部件组成、动作原理进行了介绍。经实践验证,该机械手具有很好的应用前景。     

往复移动式气动机械手的精确位置控制系统设计

介绍了往复移动式气动机械手的结构组成及各部件的作用;设计了气动回路及PLC控制系统的硬件电路;分析了利用旋转编码器进行精确位置控制的原理并设计了部分主要程序。该机械手具有控制简单、运行可靠、位置控制方便、精度准确等特点,已被广泛应用于许多领域。     

关节型码垛机械手运动学分析及仿真

根据关节型码垛机械手的结构特点,运用D-H方法建立机械手的运动学模型,并对其进行位姿、速度正反问题的分析和求解,得到关节型码垛机械手的雅可比矩阵和逆雅可比矩阵,在此基础上运用ADAMS软件对机械手码垛过程进行仿真,得到关节扭矩、关节角速度曲线,并利用仿真结果完成伺服电机的选型,为控制系统研制提供依据。     

基于虚拟样机的DELTA并联机械手动力学仿真和伺服选型

通过编程逆解DELTA机械手最大运动空间轨迹;采用虚拟样机技术,利用ProE/Mechanism和ADAMS软件对DELTA并联机械手进行动力学仿真,对比验证机构仿真结果,得出驱动轴运动参数;在此基础上,提出一种伺服电机精确选型的新方法。所建立的虚拟样机模型也为DELTA机械手的研究提供了一个运动学分析和控制的平台。     

基于PLC的敷布机吊带机械手的设计

介绍一种基于PLC控制的自动纫线机械手,设计纫线机械手的机械结构和气动系统,并给出PLC控制系统的设计。该系统应用于桥梁、巷道防水布的生产,具有稳定可靠的性能,提高了生产效率。     

数控镗铣加工中心自动换刀系统中的机-液机械手

介绍了V116B型数控镗铣加工中心自动换刀系统中的机—液机械手的结构与工作原理及其液压系统，该机械手具有结构紧凑、工作平稳、定位准确的优点。     

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.