电机转子动平衡半自动去重系统的研制

介绍了一种对电动工具用的小型电机转子进行动平衡的半自动去重系统。该系统由动平衡测试机、去重机床、PC机、单片机、多功能采集卡及其它电路组成。重点阐述了去重机软、硬件的设计过程。     

转子自适应动平衡测试系统的研究

针对工业中旋转机械的转子不平衡问题,提出基于ARM嵌入式技术的解决方案,研制转子自适应动平衡测试系统,阐述系统硬件的设计思路和软件的实现过程。在转子无试重条件下,该系统根据双面影响系数法和自学习机制,一次得出不平衡量的计算方法。根据转子转速这一关键因素,实现了动平衡测试的自适应过程。     

一种环保机械设备轴承动平衡检测系统的设计

本论文设计了一种基于单片机的动平衡检测系统,系统由STM32F407 ARM单片机控制,由控制键盘、LCD液晶显示、MPU6050模块和上位机软件模块等模块组成,具有测算航向角、横滚角和俯仰角,测量芯片温度等功能。ANO_Tech上位机实时显示传感器状态曲线,显示3D姿态。该设计突破了以往动平衡检测设备体积较大、无3D动态显示、适用性差等难点。测试结果显示,系统的欧拉角数据精度、稳定性和包括液晶屏显示、上位机3D视图等功能均符合动平衡检测系统功能要求,是一个价格低廉、功能实用的动平衡检测系统。     

基于虚拟仪器的动平衡仪设计与测试方法研究

设计出了一种基于labwindows/CVI虚拟仪器平台的动平衡机测试系统,应用谐波小波分析方法提取不平衡量信号,详细分析了信号中有用弱信号提取方法以及混杂的低频和高频干扰信号的剔除方法,设计出了一种智能型的动平衡机.系统具有功能完备、高精度、高效率、人机友好等优点,在实际中得到应用.     

基于SVR的动平衡加工误差补偿方法

针对动平衡加工误差补偿函数复杂的非线性特性,提出了基于支持向量回归机(SVR)的动平衡加工误差补偿方法.对实际转子的动平衡加工数据进行分析和处理,构造训练样本群作为SVR的输入进行训练,采用训练完毕后的SVR模型对误差补偿量进行预测.仿真结果验证了基于SVR的加工补偿方法能够有效地预测动平衡加工误差,实现高效、灵活的误差补偿,从而有效地提高动平衡加工精度.     

电网边缘终端用电时序数据自动去重系统

针对电网边缘终端用电时序数据重复问题,提出一种数据自动去重系统。基于分布式文件系统,采用客户端、元数据服务器、数据服务器以及网络通信模块等组件,构建电网边缘终端用电时序数据自动去重系统及其工作流程。通过对比分析部分去重、全局去重以及综合去重的单位时间重复数据去除量,选取综合去重法作为系统去重策略。针对用户连续两年的用电时序数据集展开系统仿真,采用空间压缩率、去重率以及吞吐量三个指标全面评估去重质量,结果验证所建系统具有较好的去重质量,吞吐量优越性较为显著。     

直升机旋翼动平衡测量方法研究

为实现直升机旋翼在高速旋转过程中动平衡值的测量，提出了一种基于阶次跟踪的测量方法。该方法首先利用阶次跟踪原理对旋翼转速信号进行等角度重采样，确定重采样的时刻值；然后利用等角度重采样时刻值，对经三次多项式最小二乘法曲线拟合后的振动信号进行二次重采样，得到旋翼振动阶次重采样信号；最后利用离散傅里叶变换方法对其进行阶次谱分析，得到旋翼的动平衡值。该方法有效克服了传统频谱分析方法在分析非平稳信号中存在的频率混叠及能量泄露等问题；同时，该测量方法通过软件实现具有较好的可移植性，能与其他直升机减振分析模块一起使用。通过在仿真试验台及试验机上进行验证试验，结果表明，该方法能有效测量直升机旋翼的动平衡值。     

汽车车轮动平衡测量系统的设计与实现

介绍了车轮动平衡仪的机械结构设计特点、电气部分基本功能及整机的结构框图,同时又介绍了车轮不平衡量的解算方法及动平衡仪复数影响系数的标定方法。该动平衡仪中恰当的应用了数字积分型相关滤波方法,取得了很好的去噪效果。编写了动平衡仪应用软件,通过产品验证了论文内容的正确性,使车轮动平衡仪得到推广应用。     

力标准机控制系统改进的设计

针对航天院所现有力标准机存在设备陈旧、操作复杂、自动化程度低、维修频繁且困难等诸多问题,为提高力标准机的力值计量效率、检测精度以及设备的可靠性,在对力标准机进行简单介绍的基础上,改进设计了杠杆式力标准机EEI-6的主控制电路、检测电路、控制箱电路、显示电路和控制部分的机械结构,以及EEI-6控制系统的软件算法、提出了改进力标准机的一种技术方案。经过改造的杠杆式力标准机能够完成自动加/卸荷、杠杆自动平衡调节等力值测量过程。鉴定结果表明改进达到了设计指标。     

柔性转子动平衡测试数据库系统开发与验证

为提高航空发动机柔性转子动平衡效率,建立动平衡数据库,用于整理、处理、归纳动平衡试验数据,为发动机的后期维护和新机研制提供技术依据.采用LabWindows/CVI软件开发平台,与MicrosoftAccess建立数据接口,设计开发了柔性转子动平衡数据库系统,对设计要求、数据来源、模块设计及其实验应用等进行了阐述,对历史数据进行管理、统计、比较以及趋势分析,为柔性转子动平衡提供数据支持.实验结果表明,试重相角、试重大小、支承方式以及转速等因素对影响系数的影响程度不同;动平衡数据库系统结构合理、运行可靠、操作方便,能够提高影响系数精度和动平衡的效率,具有一定的工程应用价值.     

弹用速率积分陀螺浮子静平衡方法研究

根据速率积分陀螺浮子的结构特点,提出用陀螺在 IA和-IA位置的零位电压之差与陀螺在 SA和-SA位置的零位电压之差来控制激光去重仪在浮子IA轴向和SA轴向的光照电流,使浮子达到完全静平衡状态的闭环工作平衡法;并采用减小力矩器刻度因数来提高浮子的静平衡精度.这种方法的平衡精度高于传统方法1～2个数量级,且平衡效率高、一致性好.     

An Extended State Observer Based Fractional Order Sliding‐Mode Control for a Novel Electro‐Hydraulic Servo System with Iso‐Actuation Balancing and Positioning

An extended state observer based fractional order sliding‐mode control (ESO‐FOSMC) is proposed in this study, with consideration of the strong nonlinear characteristics of a new electro‐hydraulic servo system with iso‐actuation balancing and positioning. By adopting the fractional order calculus theory, a fractional order proportional–integral–derivative (PID)‐based sliding mode surface was designed, which has the ability to obtain an equivalent positioning control with fractional order kinetic characteristics. By introducing the integral term into the sliding mode surface, it was found to be beneficial in reducing the steady‐state errors, as well as improving the precision of the control system. Also, by using the fractional order calculus to replace the integral calculus, the form of the convergence is improved; the system transfer of energy is slowed down; and the chattering of the system is greatly weakened. The extended state observer was designed to observe the real‐time disturbances, and also to generate the compensation control commands which are added to the FOSMC to achieve the dynamic compensation. By means of numerical simulations, the dynamic and static characteristics of the sliding mode control system were compared with those of the FOSMC and ESO‐FOSMC. The experimental results show that the ESO‐FOSMC system could effectively restrain the external disturbances and achieve higher control precision, as well as better control quantity without chattering. The semi‐physical simulations based experimental tests also demonstrated that the proposed ESO‐FOSMC outperformed the FOSMC in terms of system robustness and control precision, which could have a stable control of the gun system quickly and accurately.     

Balancing large systems of national accounts

Systems of national accounts typically contain measurement errors. Official statisticians are prepared to give initial estimates with subjective information on the standard deviations of the measurement errors of these estimates. The systems should satisfy certain accountaing identities, that is, the total incomings into any account should match the total outgoings of the account. A least-squares procedure for the adjustment of large systems of national accounts is proposed, which adjusts the initial estimates so that they satisfy the accounting restrictions. The computational requirements of this adjustment procedure are enormous as the systems of national accounts are frequently very large. Hence, the problem is reformulated and a conjugate gradient algorithm which exploits the constraint sparcity and the specific structure of economic accounting matrices is proposed. The associated computer program is self-contained, relatively cheap, and has been applied to systems of up to 262 accounts.     

Balancing of Lossless and Passive Systems

Different balancing techniques are applied to lossless nonlinear systems, with open-loop balancing applied to their scattering representation. It is shown that they all lead to the same result: the pair of to-be-balanced functions is given by two copies of the physical energy function, yielding thus no information about the relative importance of the state components in a balanced realization. In particular, in the linear lossless case all balancing singular values and similarity invariants are equal to one. This result is extended to general passive systems, in which case the to-be-balanced functions are ordered into a single sequence of inequalities, and the similarity invariants are all less than or equal to one.     

Balancing theEuLisp metaobject protocol

The challenge for the metaobject protocol designer is to balance the conflicting demands of efficiency, simplicity, and extensibility. It is impossible to know all desired extensions in advance; some of them will require greater functionality, while others require greater efficiency. In addition, the protocol itself must be sufficiently simple that it can be fully documented and understood by those who need to use it. This paper presents the framework of a metaobject protocol forEuLisp which provides expressiveness by a multi-leveled protocol and achieves efficiency by static semantics for predefined metaobjects and modularizing their operations. TheEuLisp module system supports global optimizations of metaobject applications. The metaobject system itself is structured into modules, taking into account the consequences for the compiler. It provides introspective operations as well as extension interfaces for various functionalities, including new inheritance, allocation, and slot access semantics. While the overall goals and functionality are close to those of Kiczaleset al. [9], the approach shows different emphases. As a result, time and space efficiency as well as robustness have been improved.     

Balancing of parallel U-shaped assembly lines

A new hybrid assembly line design, called parallel U-shaped assembly line system, is introduced and characterised along with numerical examples for the first time. Different from existing studies on U-shaped lines, we combine the advantages of two individual line configurations (namely parallel lines and U-shaped lines) and create an opportunity for assigning tasks to multi-line workstations located in between two adjacent U-shaped lines with the aim of maximising resource utilisation. Utilisation of crossover workstations, in which tasks from opposite areas of a same U-shaped line can be performed, is also one of the main advantages of the U-shaped lines. As in traditional U-shaped line configurations, the newly proposed line configuration also supports the utilisation of crossover workstations. An efficient heuristic algorithm is developed to find well-balanced solutions for the proposed line configurations. Test cases derived from existing studies and modified in accordance with the proposed system in this study are solved using the proposed heuristic algorithm. The comparison of results obtained when the lines are balanced independently and when the lines are balanced together (in parallel to each other) clearly indicates that the parallelisation of U-shaped lines helps decrease the need for workforce significantly.     

Competitive Analysis of Network Load Balancing

This paper presents a theoretical analysis of the Load Balancing Problem (LBP) in a network of processing units. The performance objective is to minimize the makespan, i.e., the time spent to finish all jobs in a network of processing units. Because of the communication delay that results from the network topology, it is impossible to have a strategy which obtains the exact optimum under all load distributions. Instead, we measure the information efficiency of a load balancing policy by the worst case ratio of the solution (for each load distribution) of a load balancing policy to the optimal solution (for the same load distribution) assuming that processors have complete information about the load distribution over the network. This ratio is called the competitive ratio of this strategy [17, 24, 34]. In particular, a policy is calledcompetitiveif this ratio is bounded by a constant. As a first step, we discuss the centralized LBP, where all the processors have complete information of the load distribution over a network. Its solution serves as a benchmark to compare with realistic strategies, both in theoretical analysis, and experimental and simulational studies of distributed algorithms. We show that when jobs have different sizes, even with preemptive scheduling, LBP is NP–complete. When the jobs are of the same size, we give a polynomial algorithm, using network–flow techniques, which extends to approximate solutions for jobs of different sizes. We apply this benchmark solution in order to analyze the competitiveness for three network topologies: completely connected graphs, rings, and hierarchical completek-ary trees. The constant competitive ratio results for complete network and hierarchical completek-ary trees are applied to a study on the issues of network designs suitable for the LBP. We further discuss the problem for general networks with jobs of different sizes for slightly weaker results than those for the constant competitive ratio requirement. Finally, we comment on the related issues of job partitioning over parallel/distributed systems.     

CORBA负载平衡的研究

一、引言作为分布式计算的一个重要规范—CORBA,其主要目标是解决面向对象的异构应用之间的互操作问题,并提供了分布式计算所需的多项服务。ORB是CORBA平台的核心,它用于屏蔽与底层平台有关的细节,使开发者可以集中精力去解决与应用相关的问     

Performance Characteristics of a Load Balancing Algorithm

The behavior of a graph coloring-based, distributed load balancing algorithm for a network of processors is evaluated in terms of the average response time of the system. A fundamental correspondence between average response time and Euclidean system distance (a measure of load imbalance) is analytically demonstrated. This relationship leads to the proposal of tools intended to be used in the analysis of load balancing methods. Simulation studies were conducted and are found to support the theoretical results.