直线电动机在数控机床中的应用

简要阐述了直线电动机驱动相对于传统数控机床进给驱动的优点,分析了直线电动机在数控机床应用中存在的一些特殊问题,介绍了直线电动机在高速加工、异形截面加工等方面的应用,列举了在高速进给驱动系统中的典型应用事例,并对直线电动机在数控机床中的应用前景进行了展望。     

直线电动机速度控制的研究

利用直线电动机作为快速伺服进给单元,实现机床的零传动,能达到高速高精度加工目的.但直线电动机在运行过程中进给速度越大,电动机实际运动的位置跟随理论运动的位置性能越差,如何降低系统响应的跟随误差,是使系统性能优化的关键.通过PMAC双闭环控制,专家自适应PID伺服控制环调整控制参数,能使直线电动机进给系统获得良好的动态及稳态性能.     

直线电动机在非圆截面零件精密加工中的应用研究

对具有种类多、高精度和高频响伺服控制要求的非圆截面零件加工来说,传统进给系统已难以满足要求。近年来,直线电动机作为一种新型伺服驱动进给装置,得到广泛应用。简单介绍了直线电动机在国内、外的应用现状,综述了直线电动机的基本原理及特点。利用PMAC(Programmable multi-axis controller)时基控制法,通过椭圆形等典型非圆零件表面精密加工试验,研究了基于PMAC的直线电动机的伺服控制技术和防磁散热等问题。为推动直线电动机在高速高精度数控机床中的应用打下基础。     

直线电动机应用于高速加工的关键技术

介绍直线电动机在高速加工中的地位,分析直线电动机用于进给驱动的特点,阐述直线电动机本体应用于高速加工的关键技术,包括散热问题、法向磁吸力、隔磁、工作台结构轻化等.着重概括在不确定因素影响下,闭环伺服进给驱动系统抑制外部扰动、提高稳态精度、加快动态响应以及增强鲁棒性的控制策略,根据各种控制策略的特点提出了相应的改进方法.     

直线电动机技术在数控车床上的应用

采用直线电动机技术。改变了数控机床进给系统的结构,使机床的加工精度、生产效率等性能指标得到很大的提高。为国内数控机床采用直线电动机技术。实现高速进给提供技术储备。     

高速数控机床直线进给单元的实验研究

】分析了直线电机驱动的高速直线进给单元的基本结构特征,并对这种新型直线进给单元的速度和加速度特性进行了实验研究,结果表明,当进给速度达到１ｍ／ｓ时,ＧＤ３型直线进给单元运动状态稳定,加速度达到１５ｍ／ｓ２。     

直线电机及其在超高速机床上的应用

介绍机床上应用直线电机的进展情况，研究直线电机高速数控进给单元的组成和设计中应解决的主要问题，指出直线电机的优越性，存在问题及其应用前景。     

基于PMAC下的直线电机PID控制性能研究

直线电机作为数控机床进给系统的一种新兴驱动方式,已成为现代世界机床技术发展的新趋势。文章简单介绍了直线电机的基本原理,并利用PMAC作为直线电机的控制器集成了数控磨床的横向进给单元,在利用PID 前馈控制法对直线电机控制性能研究的基础上,利用PMAC的时基控制功能结合直线电机的微量往复进给运动及电主轴单元的高速性能,实现了椭圆形零件的高速磨削精密加工,为推动直线电机及PMAC在高速高精度数控机床中的应用打下了基础。     

直线电机与高速精密数控机床进给系统的研究

直线电机直接驱动方式是一种高速精密加工进给系统的理想驱动方式。本文介绍了直线电机直接驱动的必要性，研究了直线电机高速精密进给系统的原理、单元组成和特点，并且给出了直线电机在数控车床上的应用实例。     

UKF在永磁直线同步电动机无位置传感器控制中的应用

Unscented卡尔曼滤波器(UKF)在许多非线性估计问题中是一种估计性能优于扩展卡尔曼滤波器(EKF)的非线性滤波方法。然而在永磁直线同步电动机无位置传感器控制中,UKF是否能提高永磁直线电动机位置与速度的估计性能却尚未见研究。针对永磁直线同步电动机进给系统的特点,建立用于位置与速度估计器的永磁直线同步电动机进给系统模型,提出永磁直线同步电动机无位置传感器控制系统。通过仿真和试验对UKF的估计性能进行评估,并与EKF进行了比较。仿真及试验结果表明,UKF在估计性能与EKF相当, 然而UKF的计算量却比EKF大,使得在高速永磁直线同步电动机无位置传感器控制这一特定问题上,EKF比UKF更有效。     

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...     

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。     

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...     

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。     

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.     

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.     

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.     

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...