基于柱面轮廓反求工程的数字化测量及数据处理

柱面轮廓的数字化测量及数据处理是其反求工程的关键技术，将直接影响曲面重构的精度。采用了接触式测量方式获取工件数据。这种测量方式配合测量软件可快速准确地测量出物体的基本几何形状，如面、圆、圆柱、圆锥、圆球。针对复杂曲面的数字化测量和数据处理，提出了建立形状不规则零件测量坐标系的新方法和最佳测量规划，对测量数据进行高精度的处理，得到了反求工程中曲面重构的“点云”数据。     

基于三坐标测量机的复杂曲面的逆向工程技术与实践

分析了基于三坐标测量机的复杂曲面反求过程，探讨了复杂曲面数字化过程中数据获取的方法、测量数据处理技术和曲面重构技术。     

曲面重构中测量点云精简方法的研究

反向工程研究中，根据三维测量数据进行曲面重构是其关键技术之一。介绍了曲面曲率的基本理论，根据曲率精简点云的方法及曲率估算的方法，并结合实际对根据曲率精简测量点云数据的方法进行了改进，着重研究了邻域搜索、曲率估算、曲率精简原则等，在保证测量精度的前提下，在提高曲面重构的计算效率、减少存储空间等方面取得了较好的效果。     

基于少量测量数据的复杂曲面重构

研究了少量测量数据情况下的复杂曲面反求技术,给出亍曲面重构的具体实案.以叶轮为例,介绍了复杂曲面重构中的数据采集、三维造型和误差检测、修正的方法,解决了反求工程中少量点曲面重构的技术难点.     

基于实物的复杂曲面零件反求工程中未知区域测量数据补充及曲面重构技术

针对基于实物的复杂零件反求工程中含有部分形状未知区域（如裁减曲面中的被裁减部分、测量盲区等）的复杂曲面反求CAD建模问题,提出了三种测量数据补充方法:①局部区域实物填充法。②补充设计数据补充法。③基于逼近曲面或三角曲面的测量数据自动补充法。研究了基于三角曲面模型初始表达的复杂曲面分区NURBS曲面重构方法。最后,给出了结合上述方法和反求工程软件RE-SOFT所解决的摩托车塑料件反求CAD建模实例。实践表明,综合运用所提出的数据补充和曲面重构方法,能够大大缩短实物样件的反求CAD建模时间,提高复杂曲面产品的设计效率。     

数字化技术在空间模具曲面中的应用

实物零件的数字化是通过特定的测量设备和测量方法获取零件表面离散点的几何坐标数据。因而,如何高效、高精度的实现样件表面的数据采集,一直是逆向工程的主要研究内容之一。以偏转线圈为例,运用三坐标测量机对偏转线圈曲面进行测量;然后对测量数据进行处理,数据处理包括噪声处理、点云数据重采样、基于点云的特征提取和边界曲线的建立。在数据处理的基础上,采用Image-ware软件的Fit w/Cloud and Curve来生成曲面,完成曲面重构;最后通过数控加工完成模具的加工模拟,从而实现数字化技术在空间模具曲面中的应用。     

类螺旋特征测点数据的闭曲面建模方法研究

复杂曲面及海量点云测量数据的曲面建模已成为通用CAD/CAM软件的重要功能;然而,对于复杂的闭曲面建模方法,仍然存在许多技术上的难题,至今尚未能很好的解决,比如,基于海量的测量数据,如何进行闭曲面特征点识别,如何进行区域分割与处理,这一切都使得闭曲面建模过程中很难采用已经成熟的自由曲面建模技术和方法。通过研究异步仿形测量原理以及测量数据类型,针对鞋楦测量形成的空间螺旋线数据特征,提出一种闭曲面建模方法。该方法包括如下步骤:首先对测量点数据处理;并以特征螺旋线数据为基础对曲面进行三角分割;最后,以三角Bezier曲面为基础进行曲面构造,并将各曲面进行拼接、裁剪,形成完整的曲面。采用本文方法对鞋楦测量数据的建模实例说明,该方法能够有效地对具有空间螺旋线数据特征的闭曲面进行数据处理、曲面重构,提高了产品建模效率。     

自由曲面逆向工程系统的研究

在曲面数字化规划和曲面重构研究的基础上,开发了基于非接触测量的逆向工程系统。在曲面重构数字化方面,提出基于曲面曲率和被测点切线斜率的自适应采样规划。在曲面重构方面,提出基于曲面曲率的数据点自适应压缩方法,以实现对散乱点的ＮＵＲＢＳ曲面重构。试验表明所开发的逆向工程系统是可靠和有效的。     

复杂曲面实物三坐标机数字化扫描测量的研究

数字化扫描测量是反求工程的第一步,扫描所得点云的质量直接影响重构型面的品质。针对复杂表面的坐标扫描测量研究,提出建立统一测量坐标系的方法,以及复杂、多变曲面上有多个孔径的测量规划和扫描研究。     

基于CMM测量的自由曲面反求技术研究

重点介绍三坐标测量自由曲面的反求技术。通过对自由曲面数字化过程中数据获取、测量数据处理和曲面重构的研究,得到鼠标外壳的三维模型,极大地提高了设计质量和效率。     

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。     

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...     

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.     

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.