基于步态规划的六足机器人运动学分析与计算

分析六足机器人的侧倾、俯仰、偏航变化情况,验证步态规划的正确性。对设计的六足机器人进行运动学分析,计算机器人运动学的正解和逆解,分析六足机器人运动的时序图,利用五次多项式对机器人足端轨迹进行步态规划。在ADAMS中对机器人进行了运动仿真,得到了运动过程中的RPY角。最后制作了六足机器人样机,测试运行过程中的RPY角。仿真和样机测试结果表明：机器人在步态运动过程中,RPY角度在前进方向上误差最大不超过1°,验证了运动学计算和步态规划的正确性。     

六自由度肩关节康复机器人设计与仿真

针对肩关节运动损伤康复训练问题,通过分析肩关节的运动方式,设计一种外骨骼肩关节康复机器人。对机器人的整体样机机械结构进行简单建模设计,并解决了肩关节旋转中心瞬时可变性的问题;通过D-H法推导出机器人运动学方程,并通过MATLAB验证了运动学方程的正确性。利用ADAMS软件中建立的虚拟样机模型,对机器人进行运动学和动力学的仿真,得到各关节角速度与时间的关系和各关节的驱动力矩曲线。最后通过蒙特卡洛法,计算出机器人末端运动的位置云图,得到机器人末端的运动范围。仿真分析验证了机器人结构的可行性和运动学方程的正确性,可以实现康复目的。     

茄子采摘机器人虚拟样机设计与仿真

为了取得采摘机器人最优设计,建立了采摘机器人的虚拟样机。借助Denavit-Hartenberg法建立了理论模型,确定机器人各运动构件与末端执行器在空间位置之间的关系,得到运动学方程的正解。采用Ai－1与矩阵0 T4左乘解耦,借助Matlab软件求出运动学逆解。利用Pro／e建立采摘机器人三维模型,导入ADAMS仿真软件进行运动学仿真分析。仿真结果表明：D-H法建立的运动学模型反映了机器人的真实运动情况,运动学正逆解正确。设计开发的4自由度采摘机器人虚拟样机结构设计合理,能够满足温室栽培模式下茄子采摘的要求。     

步行式可攀移作业机器人设计及运动学研究

针对大型钢结构如船舶中的检测，防腐等高空危险作业，研究设计一种新的步行式可攀移作业机器人。采用了具有行星齿轮和电磁脚的机器人结构设计，建立了机器人的运动学模型，进行了运动分析，给出了该机器人运动学数值解。通过实例运行仿真分析验证了本设计的可行性。     

基于心肺复苏用途的上肢外骨骼助力机器人仿真研究（英文）

针对心肺复苏助力用途,设计了一种新型的上肢外骨骼助力机器人。以D-H矩阵为基础建立了上肢外骨骼助力机器人的运动学方程,得到机器人末端点的位姿矩阵并验证,利用代数解法求得逆运动学。通过Matlab编程求解出上肢外骨骼助力机器人的可达工作空间。运用ADAMS对机器人进行了运动学和动力学仿真,证明了结构的合理性以及运动学的正确性,同时动力学仿真得到的各关节最大力矩为电机选型和后续的运动控制提供依据。     

基于心肺复苏用途的上肢外骨骼助力机器人仿真研究

针对心肺复苏助力用途,设计了一种新型的上肢外骨骼助力机器人.以D-H矩阵为基础建立了上肢外骨骼助力机器人的运动学方程,得到机器人末端点的位姿矩阵并验证,利用代数解法求得逆运动学.通过Matlab编程求解出上肢外骨骼助力机器人的可达工作空间.运用ADAMS对机器人进行了运动学和动力学仿真,证明了结构的合理性以及运动学的正确性,同时动力学仿真得到的各关节最大力矩为电机选型和后续的运动控制提供依据.     

XYZR焊接机器人运动学的研究

设计了一种XYZR型四自由度直角坐标焊接机器人,传动机构由x、y、z三个方向上的滑动机构和一个R方向的转动机构组成,转动机构连着末端执行机构即焊枪,在控制系统作用下,通过各个传动机构的运动实现末端执行机构的焊接功能。利用D-H参数法建立XYZR焊接机器人的运动学方程,对机器人的末端执行机构的运动进行理论推导,并利用ADAMS软件对机器人的末端执行机构进行运动学仿真研究,最后运用半实物仿真平台对焊接轨迹进行仿真测试。结果表明,由4个关节引起的运动的机器人末端位移、速度曲线变化平稳,验证了结构设计的合理性,为机器人控制系统的设计提供了依据。     

基于位姿分离法的ABB机器人IRB1200运动学分析

以ABB公司的IRB1200机器人为对象,对其运动学和工作空间进行研究。首先,简化机器人的实体结构,得到其运动机构模型,对其进行正运动学分析;然后,采用位姿分离的方法推导其逆运动学解析表达式,并对逆解过程中涉及的奇异点做了严谨的分析;最后,在Matlab中,对正逆运动学模型进行仿真运算,并采用蒙特卡洛法分析机器人的工作空间,绘制工作空间的点云图;位姿分离法完全避免了复杂的4阶齐次变换矩阵求逆运算,简单高效,有利于机器人的实时控制。     

工业机器人在MATLAB-Robotics中的运动学分析

本文设计了一种基于工业机器人的自动化处理系统,能够将工人从繁重的体力劳动中解放出来,避免了工人长时间在恶劣的环境中工作,首先需要在MATLAB Robotics环境下,建立机器人运动模型,对6R机器人的正运动学方程进行仿真验证。对机器人运动轨迹进行插补运算,运用MATLAB Robotics Toolbox工具箱编写了简单的命令程序,对工作空间内机器人进行关节轨迹规划与笛卡尔空间内的轨迹规划仿真,为6R工业机器人的运动学分析及轨迹仿真提供了参考依据。     

基于SimMechanics的新型3UPU UPS并联机器人仿真研究

针对一种新型3UPUUPS并联机器人进行了运动学和动力学分析,建立该并联机器人的运动学及动力学模型,在此基础之上运用Mat Lab中的Sim Mechanics模块精确建立该并联机器人仿真模块。根据该并联机器人的运动情况设计动平台运动轨迹,经逆解模块产生各个支链的运动轨迹,设计PID驱动控制器驱动该并联机器人进行仿真。最后将数值计算与仿真结果进行对比分析,结果表明:该种方式建立的机械模型和控制均都符合实际系统特性,并且避开了并联机构平台复杂的建模过程,对其他并联机构有很大的借鉴意义。     

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.