误差补偿法在凸轮机构测绘中的应用

介绍了凸轮机构反求设计时凸轮数据预处理方法和误差补偿理论。根据引进的凸轮测绘出实际廓线的离散型值点数据,并进行型值点数据预处理,剔除可能存在的"噪声点",并推导出凸轮理论廓线方程。再根据凸轮设计理论,应用数值计算方法求解凸轮机构从动件角位移及角类加速度值。通过将角类加速度与期望角类加速度值进行比较,得出角类加速度误差,进而求得凸轮角位移误差。通过剔除角位移误差,对凸轮理论廓线进行补偿,进而获得更接近原始设计的凸轮实际廓线的离散型值点数据,从而为该类凸轮机构反求设计提供了科学的方法。     

基于多项式拟合的共轭凸轮反求设计

介绍了一种共轭凸轮反求的方法,测绘出凸轮廓面数据,通过Pro/E建立共轭凸轮机构的三维模并进行运动学仿真分析,得到反求前从动件的位移、速度和加速度曲线。将运动曲线进行无量纲化处理,分析出特征参数,并采用有控制条件的多项式运动规律对原来的运动规律进行拟合。最后运用Pro/E对反求后的凸轮进行运动学仿真,并与反求前的凸轮机构进行对比分析,通过仿真和试制,表明这种反求方法可以有效地提高凸轮的传动精度和工作效率。     

基于组件技术的凸轮从动件运动规律反求研究

研究了从CATIA数字模型中获取凸轮轮廓曲线上离散点坐标的方法,并以这些离散点及凸轮机构基本尺寸为依据,提出了反求机构从动件的运动规律的方法。利用CATIA提供的COM功能,结合其自带的V5AutomationAPI函数开发了反求从动件的运动规律算法及程序,并对反求所得结果与理论结果进行了误差分析,研究表明提出方法是准确的和适用的。     

对称性凸轮机构从动件升程廓线多项式运动规律的参数化研究

针对仅考虑边界条件的传统多项式运动规律的最大类速度和最大类加速度偏大的问题,通过研究具有最小加速度的凸轮类位移曲线、一次映射类速度图及二次映射类加速度图,把凸轮机构从动件升程廓线分为两段单凸的样条曲线,在样条边界点上找出影响加速度曲线的敏感参数,并在样条曲线上找到一个控制加速度曲线的敏感控制点,采用数形结合的方法建立对称性凸轮机构从动件升程廓线多项式运动规律参数化模型。通过该模型能获得不同条件下的最优标准位移方程,并以此作为凸轮从动件升程运动规律曲线,设计者只需要根据确定的推程角和升程,便可方便的设计出满足从动件升程加速度最小的凸轮廓线。     

凸轮机构的反求设计

介绍了胶印机离合压凸轮机构反求设计时剔除制造误差的数据分析方法.由凸轮实际廓线测得离散数据,根据凸轮设计理论推导出凸轮理论廓线值.应用数值计算方法,计算凸轮从动件的角位移及类加速度值.将类加速度与期望类加速度值进行比较,得出类加速度误差,进而求得角位移误差.剔除角位移误差后的数据更接近原始设计数据.     

基于遗传程序的凸轮轮廓曲线设计

将凸轮机构从动件的运动规律曲线离散为数据点对,用给定的数据点对与设计曲线的数据点对的距离作为适应度函数,采用遗传程序方法对凸轮理论轮廓线进行拟合.在初始群体产生和群体进化过程中,在通常的小概率变异基础上,引入大概率强制变异算子,改进了群体的适应度.设计实例表明,利用遗传程序方法能较好地拟合凸轮理论轮廓线,并能得到凸轮轮廓曲线的解析函数,实现凸轮轮廓曲线的自动设计.     

单张纸胶印机递纸机构运动规律反求设计

介绍了定心下摆式递纸机构共轭凸轮轮廓数据的反求方法,共轭凸轮机构从动件运动规律的反求设计过程.并对反求结果进行了分析,得出正向设计共轭凸轮机构从动件运动规律的工艺要求.该方法对同类产品的反求设计有一定的参考价值.     

凸轮部件反求设计与分析

基于反求设计的方法,以3次均匀B样条曲线和周期边界条件,建立了凸轮廓线的数学模型.利用数值算法对其进行了曲线拟合和光顺,同时,利用数值仿真方法,反求分析了滑块从动件的位移、速度、加速度响应和凸轮的转角分布规律.     

基于Matlab和UG的发动机配气凸轮的三维建模

根据发动机配气需要,设定了高次多项式配气凸轮的平底从动件升程函数、回程函数和约束条件;编写Matlab的M文件程序求出高次多项式凸轮轮廓曲线、曲线的点数据和生成从动件运动学曲线,并利用从动件运动学曲线分析高次多项式凸轮轮廓的曲线性能。利用UG的曲线生成功能、实体功能获得高精度、曲线光滑连续的高次多项式发动机配气凸轮的三维模型。     

小波阈值法去噪在凸轮廓线反求中的应用

通过MATLAB小波工具箱函数,选择合适的小波函数和阈值,可以对一维信号进行有效的小波阈值去噪。在凸轮反求过程中所测得的凸轮廓线数据,可以作为两个一维信号进行小波去噪,去噪后得到新的凸轮廓线数据。对比去噪前后凸轮廓线公差带的变化,对去噪前后凸轮运动时的从动件加速度图进行对比分析,发现小波变换对凸轮廓线去噪有着良好的去噪效果,去噪后基本还原了凸轮的原始廓线。     

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。     

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.     

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。     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.