步行康复训练机器人设计研究

针对中风或者不完全脊柱损伤患者术后康复需求,设计并制作了一种移动式新型步行康复训练机器人。通过四颗按钮开关,控制减重机构实现不同比例的减重;通过HJ6霍尔操纵杆,控制步行康复训练机器人的训练模式,包括前后直线运动和左右转弯运动。利用经典力学方法对步行康复训练机器人的关键零部件进行了分析,最终选择了合适的零件。最后,制作了步行康复训练机器人样机,并进行了运动功能实验。实验结果表明:步行康复训练机器人能实现所要求的功能,基本满足患者术后康复训练的需要。     

多工位送料机械手的机构设计及速度规划

为了实现动力电池壳冲压生产线的自动化生产,在多工位拉伸压力机的基础上设计了送料机械手的机械结构,该机械手采用桁架式结构,通过X、Y、Z这3个方向的自由度上的直线运动模块来实现夹紧-张开、升举-下降和移送-回退3个动作,规划了机械手的运动周期,并在正弦速度规划算法的基础上设计了一种加加速度连续的4阶S型曲线速度控制算法,避免了机械手在运动中发生过大冲击。最终建立了机械手刚柔耦合动力学模型,通过对机械手刚柔耦合运动特性分析,研究了速度优化算法对机械手运动精度的影响,研究结果表明,在速度优化算法控制下,运动振幅明显减小,满足设计要求。     

基于机器人的抛丸机自动化生产线构造

为了提高抛丸生产线自动化水平,改善抛丸操作工作环境,采用开放式数控结构的机器人与机械手系统,结合抛丸机生产线工作特点,构造包含设备层、控制层与管理层的基于机器人的抛丸自动化生产线,利用机器人与机械手完成抛丸工件的自动上料与落料过程,实现抛丸生产线自动化.实验表明,该抛丸自动化生产线构造合理,可以满足抛丸生产自动化的需求.     

扰动观测的机械手状态约束预测跟踪控制

为了解决机械手抓取不同质量重物及伸缩连杆干扰其跟踪运动问题,提出一种新颖的定常和时变增益相结合的机械手干扰观测器设计方法,并分析观测误差系统的稳定性,目的是获得机械手工作过程中的扰动并设计控制器进行补偿;同时,为了提高机械手运动状态的安全性,提出融入模型预测控制Tp(t)的非线性鲁棒控制方法,通过同时约束机械手的运动位置跟踪误差和运动速度跟踪误差,获得系统安全的运动状态,进而保证机械手实现安全稳定的跟踪运动。通过仿真结果对比分析,表明文中提出扰动观测方法的有效性和抑制干扰实现机械手状态约束安全运动的优越性。     

人体下肢多关节连续运动的肌电预测方法

为了准确捕捉人体下肢关节在不同运动模式下的运动状态，提出一种利用肌电信号进行下肢多关节连续运动预测的方法。采集人体在蹲起运动、膝屈伸运动和上下阶梯运动时的肌电和运动数据进行处理分析，利用肌肉骨骼几何建模软件Opensim建立人体骨骼肌肉仿真模型，并进行逆运动学分析，提取人体下肢关节运动曲线。建立人体下肢在矢状面内的运动与肌电的映射关系，利用麻雀搜索算法优化Elman神经网络，实现对踝、膝和髋关节角度连续变化的预测，与传统的反向传播神经网络、支持向量机回归和Elman神经网络预测结果进行对比。结果表明：利用麻雀搜索算法优化的Elman神经网络在预测下肢关节角度变化中具有更高的精度，且该预测模型在不同运动模式下关节运动预测值与测量值均表现出一定的相关性，相关系数均大于0.89,证明利用肌电信号进行下肢多关节连续运动预测是可行的。     

基于S7-200 PLC的散热片自动化装配的控制系统设计

文章设计了基于PLC的散热片自动化装配的控制系统,该系统采用凸轮分割器传动的转盘来分配工装,用振动盘进行散热片和焊针的上料,采用光电开关进行信号的采集,用PLC实现外来信号触发的对电磁阀的顺序控制,完成了气动机械手手臂的竖直上升下降、手臂的水平伸出放回,手爪的开合,吸屑装置的开关等功能,同时通过三通开关实现了四台机械手的联动,使它们分别完成散热片和焊针的运送、夹紧电机的运动、以及成品的下料等功能,并控制电机进行散热片的钻孔和攻丝,介绍了相应的硬件和软件设计,该系统最终实现了自动装配,满足了工业需求。     

汽车变截面板簧精密成形自动化装置研究

汽车变截面板簧精密成形自动化装置主要由辊锻机和上下料机械手组成。本文介绍了机械手的基本结构特点及其所采用的与辊锻速度匹配、纵向运动缓冲和微机控制等关键技术。     

基于PLC的上下料机械手手臂设计

随着产业自动化发展和科学技术进步,效率高低是衡量工业发展水平的重要指标。简单的人工操作已无法满足工业自动化的要求。为满足工业自动化的需求,机械手成为产业自动化开发过程中的重要产品之一。它通过提高劳动生产效率,最大限度地取代人们的高强度、重复、危险、枯燥工作。本文基于PLC设计系统对上下料机械手手臂进行设计,旨在有效提高企业的生产效率,降低企业成产成本。     

压铸机连杆型喷涂机械手结构设计及其优化

设计了与压铸自动化生产相适应的连杆型脱模剂喷涂机械手,并对该机械手的相关结构参数进行了优化处理和选择。所设计的连杆型喷涂机械手可以实现对不同模具型面形状和模具厚度、不同铸件大小和厚度的模具进行脱模剂喷涂。应用线性加权法,采用Mathematic软件,通过调整取得了喷涂机构的结构优化参数,并利用自身编制的软件进行了验证。该机械手可以广泛地应用于自动压铸喷涂,稳定和提高喷涂质量。     

基于MOGWO的拟人机械手连杆长度优化北大核心

针对拟人机械手在给定约束下提升运动性能的需求,根据可操作性和端部刚度性能指标对拟人机械手的连杆长度进行优化。首先,通过分析人体手臂的运动机理得到了手臂关节的运动范围。然后利用螺旋理论建立机械手的运动学模型,并基于运动学模型得到可操作性和端部刚度性能指标。考虑到提升可操作性与提高端部刚度性能之间的矛盾,建立了相应的多目标优化模型对连杆长度进行优化。基于MOGWO(multi-object grey wolf optimization)算法求解多目标优化模型实现了拟人机械手的连杆长度优化。     

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。