直线运动机构轨迹可靠性灵敏度分析

为提高考虑不确定性因素影响下的直线运动机构轨迹精度,提出了直线运动机构轨迹可靠性灵敏度分析的解析算法。首先,利用等距曲线构造运动轨迹的界限,考虑机构的构件尺寸公差,提出包含机构结构误差和随机误差的误差分析模型,并采用线性化方法导出机构运动误差的统计特征值的解析表达;其次,采用一次二阶矩方法建立了直线运动机构轨迹可靠性分析模型,并推导了机构轨迹可靠度对随机变量均值和方差的灵敏度分析的解析模型;最后,以Hoeken机构为例作了数值计算。     

码垛机器人运动精度可靠性及其灵敏度分析

运动精度是评价机构质量的重要考核指标.针对码垛机器人四杆机构,运用矩阵法建立了机构输入,输出关系的运动精度分析模型.在考虑了基本尺寸误差和运动副间隙误差的基础上,运用二阶矩和摄动法给出了码垛机器人四杆机构运动精度可靠性的设计方法,并结合算例求出了不同间隙误差情况下机构位置精度的可靠性指标,并计算出其可靠度.结合可靠性的分析结果,运用可靠性灵敏度技术在算例中给出了码垛机器人四杆机构各随机参数可靠性灵敏度的变化规律.     

车辆转向机构运动精度的可靠性稳健优化设计

在车辆转向机构设计中,考虑了可控因素和噪声因素对运动精度的影响,将可靠性优化和稳健设计方法相结合,以转向机构运动精度为目标函数建立转向机构的可靠性稳健优化数学模型.把运动精度的可靠性灵敏度溶入可靠性优化设计模型之中,将可靠性稳健优化设计转化为满足可靠性要求的多目标优化问题.实例计算表明,考虑制造误差、运动副间隙等不确定因素的影响,可靠性稳健优化设计方法能有效保证转向机构的运动精度和可靠性.     

摆动推杆盘形凸轮机构运动精度可靠性分析

运用多种误差分析方法,从机构运动学角度,研究了摆动推杆盘形凸轮机构在考虑基本尺寸误差、运动副间隙及凸轮和滚子表面被磨损三种情况下的摆杆摆角误差的计算方法。以可靠性工程和概率论理论为基础,将各种原始误差均视为随机变量,建立了综合考虑各项误差的机构运动精度可靠性分析模型,提出了相应的摆动推杆盘形凸轮机构运动精度的可靠性分析和计算方法。     

平面轨迹机构的运动可靠性分析

单自由度轨迹机构具有单输入多分量输出的特性。传统机构运动可靠性理论对各输出分量误差独立建模以建立机构运动的可靠性分析模型,该分析模型不能反映机构运动的整体失效情况。为此,提出了一种基于圆形区域的误差模型和可靠性分析模型,并采用1阶可靠性算法对可靠性分析模型求解。为提高模型求解精度,提出采用遗传算法并结合序列二次规划的混合优化算法实现最大可能点的求解。数值实例验证了该方法的有效性。     

爬楼轮椅座椅姿态调节机构的可靠度及灵敏度分析

爬楼轮椅座椅姿态调节机构为一新型两自由度交叉四连杆机构,其运动精度直接影响着爬楼轮椅运动的稳定性。针对座椅姿态调节的交叉四杆机构,利用矩阵的方法建立了机构输入、输出关系的运动精度分析模型,进而建立了机构运动精度的可靠度及灵敏度数学模型。在基本尺寸误差和运动副间隙误差的基础上,求解出了三种运动副间隙误差情况下机构运动精度的可靠度。同时,也求解出了在不考虑运动副间隙误差情况下机构中各基本参数的可靠性灵敏度,最后利用Matlab进行仿真发现机构保持了较高的可靠度及适当增加杆长可改善机构的灵敏度。     

平面连杆机构运动误差及可靠性分析

为获得考虑运动副间隙和杆长误差的平面连杆机构运动规律，采用复数矢量法，推导出运动误差计算公式，在此基础上建立了曲柄滑块机构运动精度可靠性分析模型，编制了相应的计算机软件，并计算出算例机构位置参数和输出运动误差的方差和可靠度。     

基于ISCA的盘形凸轮机构运动可靠性优化设计

为分析基本尺寸误差、运动副间隙对盘形凸轮机构运动精度的影响,建立了考虑两种误差的摆动推杆盘形凸轮机构运动可靠性、可靠性灵敏度数学模型.为使机构运动可靠性最大化,利用改进的正弦余弦算法(Improved Sine Cosine Algorithm,ISCA)对某摆动推杆盘形凸轮机构进行参数组合优化设计,得到机构最优参数组合;通过分析可靠性灵敏度可知,凸轮轴轴心与摆动回转中心距离误差对机构运动可靠性影响最大.实例分析表明,该方法在提高盘形凸轮机构运动可靠性方面具有较好的适用性,为各种凸轮机构的设计提供了一定的参考价值.     

面向构态切换稳定性的约束变胞机构可靠性优化设计方法

为获得稳定、可靠的构态切换能力而开展可靠性优化设计是降低约束变胞机构运动功能失效概率的关键。基于多构态欠驱动约束变胞源机构的组成原理建立了含变胞运动副的扩展Assur杆组的模块化受力分析模型。根据变胞运动副的等效阻力梯度模型，考虑系统内外部误差的随机性，利用可靠性理论建立了约束变胞机构构态切换能力的概率评估模型。基于可靠性评估及可靠性灵敏度分析，提出了面向约束变胞机构构态切换稳定性的可靠性优化设计方法，进而针对可靠性灵敏度较高的结构参数随机变量的公差进行优化设计，使优化后的设计方案同时满足可靠性和经济性要求。最后，以折纸变胞机构为例，验证了提出的可靠性优化设计方法的可行性和有效性。研究工作为开展面向高概率的构态切换重复执行能力的变胞机构可靠性优化设计奠定了基础，同时对推进变胞机构的工程应用具有理论和实际意义。     

一种机构运动可靠性的研究方法

利用机械系统动力学分析软件—ADAMS作为机构运动可靠性分析平台，进行机构的变参数设计，从而建立机构运动可靠性的仿真模型进行仿真分析，并应用蒙特卡洛法进行计算，在整个求解过程中，不需根据机构运动建立、求解复杂的解析数学方程，是机构运动可靠性分析计算的一种行之有效的方法。以曲柄滑块机构为例，研究考虑几何尺寸误差和运动副间隙误差对机构运动可靠性的综合影响。与传统方法相比较，使用该方法所得结果更加精确，而且适用于复杂机构，便于工程实际应用。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.