一种8自由度空间机械臂运动学及工作空间分析

针对太空环境,提出一种带有移动副的8自由度机械臂,可完成太空环境中的设备维修、物品抓取等工作。通过标准D-H参数法,推导了8自由度机械臂的位姿变换矩阵和正运动学方程;利用MatlabRobotics工具箱,建立机械臂的仿真模型,将仿真模型与机械臂运动学方程进行对比验证;采用蒙特卡罗法对机械臂工作空间进行求解,绘制了机械臂末端执行器的工作空间点云图;通过Matlab对机械臂进行轨迹规划仿真研究,绘制运动过程中各关节的位移、速度、加速度变化曲线,验证了机械臂结构设计的合理性,为后续的研究工作提供参考依据。     

八自由度机械臂正运动学及工作空间分析

对一种八自由度机械臂的正运动学和工作空间问题进行了研究。首先,根据机械臂的结构特点,利用D-H法建立了该机械臂的连杆坐标系,得到其运动学正解;其次,利用MATLAB Robotics Toolbox建立机械臂的仿真模型,验证了机械臂运动学正解的正确性;最后,根据末端执行器的位置向量,采用蒙特卡洛法对机械臂的工作空间进行了分析,得到机械臂末端执行器的工作空间范围,仿真结果与机械臂的设计参数相符。     

一种车载轮椅自动收放机械臂设计与运动分析

提出了一种用于车载轮椅自动收放的5自由度机械臂。首先,根据D-H方法建立机械臂数学模型,并进行正向及逆向运动学分析,在进行逆向运动学分析时,分别用解析法和反向传播（Back Propagation,BP）神经网络进行了求解;其次,采用五次多项式插值法对机械臂进行关节空间轨迹规划,实现机械臂的平滑无冲击运动;随后,基于蒙特卡罗法分析机械臂工作空间,得到机械臂末端的工作空间点云图;最后,针对具体车载应用场景,开展了虚拟仿真实验。仿真实验结果表明,机械臂构型设计合理,运动灵活,满足应用需求。为样机开发及应用提供了理论依据。     

六自由度机械臂运动学分析与仿真研究

针对六自由度机械手臂的运动学分析问题及其工作可靠性的探究,设计开发了一套基于OpenGL的六自由度机械臂仿真软件.采用D-H参数法构建机械臂模型,对六自由度机械手臂进行了正、逆运动学分析,求解得到机械臂的正逆解.研究设计了机械臂的空间直线和圆弧插补算法,实现了机械臂在三维空间中按照目标轨迹的可靠运动.在VS2017软件...     

基于MATLAB的四自由度机械臂运动学仿真研究

运用D-H法建立机械臂运动学方程,根据所求方程采用数值法进行分析,并用MATLAB软件对分析结果进行仿真,得到机械臂的可达工作空间图。用Robotics Toolbox对该机械臂的正运动学、逆运动学、轨迹规划进行仿真,得到各关节角的位移、速度、加速度与时间关系曲线,为后续机械臂控制系统设计、动力学分析以及轨迹规划等提供理论基础。     

推力矢量控制机械臂运动规划及仿真

提出了一种将推力器置于多自由度机械臂末端,并对末端推力进行矢量控制的四自由度串联机械臂。首先,对推力矢量控制的理论意义及研究现状进行了简要介绍,并提出了研究方向;其次,对该串联机械臂的结构和连杆参数进行了分析,采用D-H参数法建立了该机械臂的运动学模型,并采用代数法求解出正向和逆向运动学方程;最后,利用MATLAB中的robotics工具箱仿真分析了该机械臂的工作范围,并通过算例验证了所求解的运动学方程的正确性。结果表明,该结构类型的机械臂可作为推力器,并通过推力矢量控制方法调整空间飞行器的位姿。     

双臂协作机器人动态精度设计及工作空间分析

针对双臂协作机器人在票据自动报销处理过程中,票据高速移动、翻转、高精度动态对位及机械臂完备工作空间设计等问题进行详细分析。通过D-H约定建立机械臂空间坐标系,求解相应正逆运动学方程,并根据正运动学方程求出机械臂末端工作空间云图,运用蒙特卡洛法遍历双臂相对距离取值范围,求取工作空间最大交会情况下双臂相对距离。对末端执行器不同对接位置进行仿真研究,分析末端执行器平均加速度波动情况,获得动态精度最优情况下的位置参数,为双臂机器人动态精度设计及精准控制奠定基础。     

基于改进脊线法的超冗余机器臂逆运动学求解

针对传统机器人尺寸大、自由度少,无法在狭窄空间内作业的问题,设计了一种基于新型球形关节串联而成超冗余机械臂,每个球形关节具有两个正交旋转自由度。因超冗余机械臂自由度数远多于传统机器人,无法用D-H法对其进行逆运动学求解,本文考虑机械臂运动过程中障碍物的影响,对脊线法进行改进,提出基于改进脊线法的超冗余机械臂逆运动学求解算法,利用Matlab对空间脊线及超冗余机械臂逆运动学进行数值仿真。研究结果表明,该算法考虑了障碍物的影响,改进了超冗余机械臂逆运动学脊线法,保证了超冗余机械臂的灵活性。     

扬琴自动演奏机器人机械臂设计

为促使我国民族乐器自动演奏机器人的进一步发展,设计一种能拟人化敲击的扬琴自动演奏机器人机械臂。根据D-H参数法建立机械臂的运动学模型并求得运动学方程的正解,利用反变换法求得机械臂运动学方程的逆解,从而验证运动学模型的正确性以及为机械臂运动控制提供理论基础。利用Solidworks三维建模软件建立机械臂的虚拟样机模型,对其进行运动过程仿真,仿真结果验证了机械臂结构及连杆参数设计的合理性。制作试验样机进行实验,进一步证明机械臂设计的可行性。为扬琴自动演奏机器人机械臂的后续研究提供了理论基础。     

5_DOF取皿机械臂设计与虚拟样机仿真

根据微生物培养过程中需对培养皿抓取和分拣的工作要求,设计了一款5自由度小型机械臂,通过UG软件建立其三维模型。利用D-H法建立其连杆坐标系并作运动学分析。采用MATLAB建立机械臂数学模型并对其工作空间进行分析与验证。将该三维模型导入到ADAMS软件中进行运动学/动力学仿真分析,得出机械臂各关节角速度、力矩等参数曲线,仿真结果可为该机械臂的物理样机制造与取放皿操作实验提供参考。     

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.