基于MATLAB Robotics Toolbox的UR5机器人轨迹规划与仿真

为了解UR5机器人实时轨迹变化情况,根据Denavit-Hartenberg参数法在MATLAB Robotics Toolbox中利用Link函数建立了UR机器人的三维数学模型,对UR5机器人进行了正、逆运动学求解与理论分析,推导出各个关节角之间的变化关系;利用三次多项式插值法对任意PTP (点到点)之间的空间轨迹规划进行理论分析,并结合MATLAB Robotics工具箱对UR5机器人数学模型进行了空间轨迹规划和仿真,得到了连续变化的轨迹曲线。仿真结果验证了机器人运动学模型的正确性和合理性,为UR系列机器人的进一步研究和应用提供了理论依据。     

光伏板智能清洁机器人设计与实现

为有效解决光伏板表面灰尘覆盖问题,提高光伏电站光电转化效率,根据目前光伏板安装环境,设计一种光伏板智能清洁机器人。机器人由行走机构、清洁机构、控制模块以及各传感器组成,可在光伏板上自主进行清洁工作。对机器人的行走机构和清洁机构进行设计计算,再通过力学分析得出机器人运动稳定性条件,然后结合机器人功能对机器人的控制系统进行设计,最后制作出机器人样机。通过对机器人进行运动和清洁性能测试,此机器人可在25°以下的斜面上稳定运动,清洁机构对于浮尘或积垢类污渍都具有一定的清洁能力,且机器人可按照设计路径自主完成清洁工作。与传统清洁方式相比,在解决光伏板灰尘覆盖问题的同时,极大地降低了人工成本,减少了水资源的浪费。     

UR10机器人的运动学分析与轨迹规划

为了让机器人在作业过程中运动轨迹具有连续、平滑的特性,对6自由度机械臂进行了运动学分析和轨迹规划。以6自由度的UR10机器人为研究对象,以刚体运动的齐次变换理论为基础,应用改进的D-H法对UR10机器人进行了运动学建模,基于几何与代数法对机器人进行了正、逆运动学分析,得到笛卡尔空间中末端执行器的位姿与关节空间中机器人关节角度之间的映射关系,并通过实例验证了公式推导的准确性。最后,基于MATLAB机器人工具箱,应用梯形的速度混合曲线对UR10机器人进行轨迹规划的仿真实验。试验结果表明:基于梯形的速度混合曲线得到的轨迹规划,实现了机器人的运动轨迹的连续和平滑。     

智能化泵车臂架电液操控技术的开发与研究

混凝土泵车臂架系统是一组具有多冗余度的机构,利用人工进行操作时很难实现自动连续浇筑.利用机器人技术、虚拟障碍技术、插补算法等规划混凝土泵车自动浇筑时各臂架的运动轨迹,利用电液比例控制系统进行智能化控制.对混凝土泵车自动浇筑过程进行运动学和动力学仿真,对各臂架电液控制系统进行建模分析及优化设计.动力系统的联合仿真结果表明,泵车的浇筑口能够很好地沿着根据虚拟浇筑环境自动规划的浇筑轨迹进行浇筑.     

基于区域规划法的泵车臂架系统反解算法及自动浇筑轨迹

以五节臂混凝土泵车为研究对象,根据串联机器人理论,建立混凝土泵车臂架系统的D-H矩阵,并进行臂架系统运动学正解分析。提出基于区域规划法的泵车臂架系统末端的反解算法。对混凝土泵车臂架系统工作空间内的直线浇筑轨迹进行规划,并对2种典型的轨迹进行反解计算。结果表明：基于区域规划法的泵车臂架系统反解算法简化了臂架反解运算过程,且反解唯一、计算量小、实时性高,易于在工程机械运动控制器上实现。     

焊接机器人虚拟样机轨迹模拟和运动仿真分析

根据焊接机器人的结构特点,对其进行了模型简化,在对机器人进行正向运动学分析的基础上,运用Denavit-Hartenberg(D-H)矩阵法,求解出焊接机器人末端位姿的数学模型,完成了焊接机器人空间位姿的描述;运用ADAMS软件,建立了焊接机器人的虚拟样机模型,仿真得出了模型的末端轨迹,并与数学模型求解结果进行对比,验证了数学模型的准确性与可靠性;对其进行运动仿真分析,测量并研究了机器人各关节运动学参数的变化情况,为后续焊接机器人的设计和制造提供了依据,对于精确确定焊枪工作位置、确保焊接质量、降低产品废品率有重要意义.     

基于MATLAB的KUKA焊接机器人轨迹规划与运动学仿真

在工业机器人的应用控制中,其作业轨迹的规划是系统设计的关键内容,为了使焊接机器人能根据设定的轨迹和速度进行高效施焊,以KUKA KR10 R1420型工业机器人为研究对象并分析其结构,采用D-H参数法建立各杆件坐标系,通过齐次变换矩阵建立机器人运动学方程。利用MATLAB机器人工具箱构建KR10 R1420型工业机器人的数学模型,并进行了轨迹规划和运动学仿真,获得平稳且连续的末端执行器轨迹和各关节的角度、角速度、角加速度变化曲线,仿真结果验证了所建KR10 R1420型工业机器人运动学模型的正确性和合理性,为焊接机器人在复杂环境中的轨迹规划提供了可供参考的方案。     

六自由度经济型工业机器人设计与运动学分析

设计了一种六自由度经济型工业机器人,从经济性考虑,完成了驱动电机、减速器及控制器的选型和各关节的结构设计,在保证性能要求的情况下降低了机器人的成本。根据D-H方法建立机器人的运动学数学模型,得出机器人末端点的运动方程,在Matlab环境下,采用蒙特卡洛法求出机器人的工作空间点云图,运用Robotics Toolbox对该机器人进行仿真建模,并进行了实例仿真。通过仿真结果分析机器人的运动情况,验证了运动学算法的正确性,符合预期的设计目标,为机器人轨迹规划和控制的研究提供了可靠的依据。     

基于虚拟样机的六自由度弧焊接串联机器人的运动仿真

针对弧焊接机器人的特点,建立了六自由度串联机器人D-H运动学模型,对模型进行了运动学分析。提出了基于多项式函数插值法的空间轨迹规划方案,算例验证显示:手臂运行平稳,空间点全部在机器人工作空间以内。为模拟实际工作过程,进行了虚拟样机仿真,仿真曲线平稳,无骤变现象,验证了该机构的合理性。     

基于ADAMS的SCARA机器人运动学仿真研究

对SCARA机器人进行正逆运动学分析以及轨迹规划仿真时,不易直观地验证运动学算法的正确性和轨迹规划的效果。为解决以上问题,基于ADAMS软件环境,建立了SCARA机器人的三维虚拟样机模型,结合SCARA机器人的正逆运动学在笛卡尔空间对其末端规划一段圆弧路径轨迹,并将该圆弧路径轨迹数据导入虚拟样机模型中进行轨迹规划的仿真。结果表明,该系统为SCARA机器人运动学分析及轨迹规划方法的仿真验证提供了一个有效的平台。     

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.     

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.