基于样条插值算法的工业机器人轨迹规划研究

工业机器人的控制系统是封闭且独立的，通过示教方式来在线编程是很难完成复杂的曲线运动，效率较低。为此在工件面型图像中对待加工轨迹进行规划，根据三次B样条曲线插值算法对规划好的加工路径轨迹进行数据处理，通过离线编程把加工轨迹数据点格式转换成机器人程序文件，把复杂的曲线运动分解成直线运动和圆弧运动，从而实现工业机器人的复杂曲线运动。实验过程中机器人运动流畅没有停顿，实际运动轨迹和规划运动轨迹吻合得很好，证明该方法有效可行。     

弧焊机器人虚拟示教编程系统

以MOTOMAN-UP20弧焊机器人为研究对象,建立了基于ROTSY的弧焊机器人虚拟示教编程系统.介绍了该系统的组成和虚拟示教编程的详细过程.采用客户/服务器通信模式,通过以太网实现了弧焊机器人的远程控制.对马鞍形焊缝轨迹进行动态仿真,结果表明该系统是可行的,通过虚拟示教功能可以实现焊缝路径的规划和机器人程序的自动生成.     

基于数字孪生的发动机螺栓拧紧研究

航空发动机种类多、形状大小各异,传统的示教编程刚性螺栓拧紧方法因其效率慢、安全性差、编程门槛高等缺点,不再适用于中小批量多类型的发动机螺栓拧紧工作。提出一种基于数字孪生的柔性拧紧发动机螺栓的方法,包括螺栓拧紧方案、螺栓拧紧过程数字孪生仿真、物理空间与数字空间一致性标定等。通过D-H参数法建立机器人运动学模型,进而对机器人进行运动学求解,通过五次多项式插值法对机器人进行轨迹规划。通过数字孪生仿真生成离线程序,利用一致性标定消除坐标偏差。分别利用离线编程与示教编程进行3组实验,结果显示：离线编程与示教编程均能完成航空发动机的螺栓拧紧工作,但基于数字孪生的柔性螺栓拧紧方法可以快速又柔性地拧紧航空发动机的螺栓。     

夹持工件打磨机器人离线编程及仿真系统设计

打磨加工对机器人运动轨迹精度要求很高。针对常规的在线示教编程不能满足打磨加工精度的问题,以Visual C++为开发平台,基于MFC框架以及OpenGL图形库接口搭建机器人离线编程仿真系统,实现机器人离线示教、程序编辑、建立轨迹目标点数据库等功能。通过基于工件模型STL文件分层切片生成机器人运动轨迹的方法,求得交点的姿态并得到机器人加工轨迹位姿的齐次矩阵,最后将获得的机器人打磨轨迹参数导入离线编程系统中,编程实现机器人打磨加工的可视化仿真。     

基于OpenGL的多机器人仿真实验平台研究及实现

多机器人协同工作广泛应用于现代化工业生产现场,协同控制是实现多机器人协同工作的技术保障。针对多机器人协同控制研究中的轨迹规划、轨迹优化和碰撞检测等算法研究需要,以及多机器人工作站离线编程、虚拟示教等研究实现需要,提出基于OpenGL和MFC建立具有完全开放性、自主性的多机器人协同工作算法研究仿真实验平台,嵌入机器人正、逆运动学、轨迹规划、碰撞检测等算法,实现多机器人三维虚拟仿真、离线编程和虚拟示教,并进行单个实体机器人实验验证。实验结果表明:基于OpenGL和MFC建立的多机器人协同控制仿真平台,可以进行多机器人协同控制相关算法研究,另外离线编程与虚拟示教转换生成程序指令可以按照要求控制机器人运动。用户无需进行三维图形仿真编程、界面编程和辅助算法研究及实现,只需侧重其算法研究,即可基于该软件实验平台快速进行机器人、多机器人算法仿真验证及效率分析,减少工作量。     

MATLAB环境下关节型焊接机器人仿真平台设计

Motoman-HP20焊接机器人的离线编程软件MoToSimEG进行轨迹规划采用点到点的方式,对于一些复杂曲线,需要非常多的约束点才能达到较高的精度要求,导致编程过程复杂繁琐。针对这一缺点,开发了一套基于MATLAB环境的六自由度关节型焊接机器人仿真平台实现人机交互,并进行了数据通信完成实验验证。验证结果表明:仿真平台不仅可以完成点到点的关节空间和直角坐标空间的轨迹规划,也可以实现任意已知解析式的轨迹规划运动,并得到轨迹数据完成了示教再现,简化了机器人复杂运动轨迹的编程方法,进一步改善了轨迹规划离线编程功能。     

机器人操作臂离线编程仿真系统

简述了离线编程仿真系统相对传统示教编程的优势,提出了基于OpenGL与QT的机器人操作臂离线编程仿真系统,建立机器人操作臂及工件的三维模型并实现了机械臂的运动学动态仿真。设计开发了离线编程仿真系统各功能模块,包括机器人语言编程模块(编程语言及其翻译器)、运动规划模块、机器人运动仿真模块、模型管理及辅助模块等。最后给出了仿真系统对机器人搬运工件的应用实例。     

多层多道焊机器人离线编程路径规划

面向机器人多层多道焊接轨迹人工示教编程效率低、难度大的问题,为了提高焊接质量与效率,基于OpenCASCADE建模引擎,开发多层多道焊机器人离线编程软件,从工件模型中提取焊缝信息,取代在线示教操作。提出一种用户自定义焊层焊道数目的路径规划算法,确定每个焊道的空间位置、焊接速度,同时规划焊枪末端姿态,避免与工件发生碰撞。通过机器人加工仿真运动,表明各个焊道位置准确、姿态平顺,验证了路径规划的正确性与可行性,并在实际焊接试验中获得良好的焊接效果。     

基于激光定位技术的机器人非接触无编程示教方法与实现

针对现有机器人示教系统操作复杂、示教编程难度高及需操纵机器人等问题,提出一种基于激光定位技术的机器人非接触无编程示教方法。以示教笔代替机器人末端工具绘制示教轨迹,通过激光定位技术获取示教笔的示教路径和动作,并通过机器人逆运动学求解及轨迹规划得到各个关节的控制轨迹,实现机器人的快速非接触无编程示教。最后通过搭建桁架式六轴机器人硬件和软件系统,实现了基于激光定位技术的机器人非接触无编程示教,验证了提出的示教方法的可行性。所提示教方法简化了示教过程,降低了操纵机器人带来的安全风险,且无需操作人员具备编程能力,使机器人示教工作具有良好的适应性,具有广阔的应用空间。     

一种一体化焊接机器人示教控制器的设计

设计了一种能够实现机器人示教编程、空间运动插补运算求解以及机器人运动控制的焊接机器人嵌入式示教控制器。采用UCOSII实时操作系统进行多任务管理,能够同时驱动四个主轴电机和两个附加轴电机运动,基于em Win图形库设计TFT液晶屏的显示功能,实现人机交互。设计基于逐点比较法的空间插补算法,大大降低系统对硬件的要求。最后通过xyz+R四轴焊接机器人实物仿真和MATLAB软件仿真对示教控制器进行模拟测试。测试结果表明,不管是平面轨迹还是空间轨迹,示教控制器都能在简单的操作下得到良好的再现轨迹,误差在1 mm之内。系统稳定性好,成本合理,利于直角焊接机器人的推广应用。     

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。