混合驱动凸轮连杆机械压力机的分析与仿真

分析了将混合驱动凸轮连杆机构应用于机械压力机的意义,提出了一种混合驱动凸轮连杆机械式压力机的机构构型,分析了其运动原理。用回路矢量法对混合驱动凸轮连杆机械压力机进行了运动学分析。并给出了一个设计实例,利用Pro/Mechanism模块对其进行了机构运动仿真,结果表明该机构能使滑块实现多种运动规律以满足加工要求。通过对混合驱动七杆压力机的结构特性和运动仿真分析,得出了混合驱动凸轮连杆压力机相对混合驱动七杆压力机具有杆长条件容易满足和滑块输出运动规律特性好等优点。最后建立混合驱动凸轮连杆压力机的动力学模型,对其进行了功率分配研究。     

基于AutoCAD的集中驱动凸轮-连杆组合机构设计与仿真

考虑多个执行构件有动作配合要求的情况,在分析运动循环图基础上,用解析法完成了集中驱动凸轮-连杆组合结构的设计方法,建立了相应的数学模型.基于AutoCAD VBA开发技术,实现了该组合机构数字化设计与仿真程序的编制.     

高速凸轮动态设计方法研究

建立了高速凸轮机构的动力学模型,并简化为单自由度动力学模型.求得该模型的动力学方程,推算出凸轮轮廓线设计方程,进而实现了高速凸轮的动态设计.利用该高速凸轮的动态设计方程对一个实例进行仿真设计,得出了凸轮轮廓设计曲线.仿真结果表明：得到的高次多项式曲线光滑而无冲击,满足凸轮高速运转时的动力学特性要求.     

高速无菌砖式包装容量调整系统动力学分析及机构设计

采用凸轮连杆组合机构设计出了应用于高速无菌砖式包装机的容量调整装置.对此凸轮连杆组合机构作了线性传动分析.该机构中的凸轮由摆动滚子、移动凸轮段和摆动滚子、从动盘形凸轮段构成,对盘状凸轮段和移动凸轮段的廓线做了研究,并给出了凸轮廓线方程及压力角和曲率半径的计算公式.     

一种新型凸轮-连杆组合分度机构的运动学分析

针对自动化机械要求实现高速分度的需求,提出一种新型的凸轮-连杆组合分度机构。在系统分析该机构的结构与传动原理的基础上,将其在运动学上等效为以组合分度机构的输入、输出构件为驱动构件的五杆机构。在此基础上,采用多刚体运动学分析方法,推导了系统的约束方程,进而建立等效机构的运动学分析模型,得到了各构件在一个分度周期内的运动规律。文中研究可为该机构的运动学设计及动力学分析奠定基础,采用的多体运动学分析方法可为同类机构的运动分析提供借鉴。     

实现直线等速运动凸轮-连杆组合机构的优化设计

凸轮-连杆组合机构由于具有凸轮机构和连杆机构的优点,因此在实现复杂运动轨迹或满足某些特定要求方面,是很有发展前途的一种机构。 本文对用于缝包机的送布机构——凸轮-连杆机构进行了比较系统的分析研究,按特定的运动要求建立了目标函数和约束条件,借助于计算机进行优化设计。通过优化设计,不但改善     

集中驱动凸轮-连杆组合机构优化与仿真

考虑多个执行构件有动作配合要求情况下,在分析运动循环图基础上,用解析法完成了集中驱动凸轮-连杆组合结构的设计.运用Matlab,分别以最大压力角最小及机构尺寸空间最小作为目标函数,对凸轮和连杆机构进行优化.在AutoCAD下编写凸轮-连杆组合机构仿真程序,运用优化所得数据查看运行结果.实现了集中驱动组合机构的优化设计与仿真.     

食品包装机中的机构设计

食品包装机机构应具有运动可调的特性,故常采用凸轮-连杆组合机构。但在设计中,判断其能否传动的问题,往往不能沿用通常的传动角或压力角概念。本文结合食品包装机中的一些典型机构拟从机械效益角度来研究这一问题。 一、端封机构     

面向足式机器人腿部运动的组合机构反求设计

为实现行走机器人的运动需求,并考虑凸轮-连杆机构能够实现复杂的运动轨迹优点,根据行走机器人腿部运动轨迹,开展凸轮-连杆组合机构反求设计。通过复数矢量法对组合机构进行运动分析,利用Newton插值理论获取共轭凸轮输出摆杆的角位移函数,并基于解析法反求凸轮轮廓线方程,最终在MATLAB中实现凸轮轮廓线的绘制。结果表明设计的共轭凸轮-连杆组合机构可满足行走机器人的腿部运动要求。     

高速凸轮机构动力学分析及模态截断

高速凸轮机构广泛应用于车辆、纺织和印刷等机械中,对其进行动力学问题研究是提高机械性能的基础和关键。采用有限元法对凸轮机构柔性构件进行离散化处理,结合模态综合技术和Kane方程建立刚柔耦合凸轮系统动力学模型,所得动力学方程是一个更具一般性的柔性梁类动力学方程,且该方程在模态坐标下更便于计算机求解运算。通过对系统模态分析和动力学方程求解来分析其动态性能,在了解系统动态性能的同时进行模态截断研究。对截取不同阶数的动力学模型进行仿真,分析模态截取阶数对计算精度和计算速度的影响。研究结果对判断实际应用中的高速凸轮系统是否需要进行动力学分析具有重要指导意义,也为该类机构的动力学建模和模态特性研究提供依据。     

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...     

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。     

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。     

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.     

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.     

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。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.