利用386微机实现宽转速范围高精度转速测量

本文介绍了一种基于386微机的转速测量方法,该方法克服了一般数字式转速测量方法高、低速精度不等以及精度不高的缺陷,可实现宽转速范围的等精度测量,测量精度可达2.3×10~(-10)。     

基于变精度粗糙集的柴油机监测点优化

为获得有效的柴油机振动信号监测点,提出了一种基于变精度粗糙集模型的测点优化方法。该方法在保证集合相对可辨别性的前提下,计算各个测点的阈值,并以此作为测点优劣的评判标准。以某大功率柴油机为例,采集不同测点位置的振动信号,并提取频域特征值;应用基于变精度粗糙集的方法进行测点的优化计算,与实验结果进行对比,表明该方法能够有效区分不同测点位置以及不同故障类型的敏感程度,从而得到效果较好的振动信号监测点位置,同时减小噪声对故障诊断的影响,有利于提高故障诊断的准确率和效率。     

基于单片机的发动机转速测量系统的分析研究

本文介绍了基于霍尔脉冲发生器与单片机的转速测量装置的组成及转速的测量方法,分析了该种测量方法的测量精度以及测量精度与转速的关系。并讨论了转速测量数据的滤波方法。     

飞机发动机转速实时在线检测系统二次开发

介绍一种以AT89C52单片机为系统控制核心,用二相步进电机精确地驱动仪表指针,对飞机发动机转速实时在线检测系统进行研究与开发,实现机电一体化功能的智能仪表技术。     

机车柴油机转速测量新方案与实现

有效利用交-直流电传动内燃机车工作及传动特点，不需要使用专用的转速传感器，采用频率比较方法，就能实现对内燃机车柴油机转速的快速精确测量。经机车维修使用表明，该方法经济实用，可靠性高，操作便捷，为机车柴油机转速测量提供了又一新的方案。介绍了测速原理、方法及具体实现。     

基于角域振动信号特征统计量的发动机故障分类方法

为了提高发动机故障分类的准确率和成功率,提出了基于角域信号特征统计量的发动机故障分类方法。包括：利用编码器进行发动机振动信号的等角度采样;采用小波包分析和相关系数法获取发动机角域信号的特征阶次;选取特征阶次信号的能量比、标准差比、谱能量比及谱均值比4组参数作为角域信号特征统计量来提取发动机故障特征;采用支持向量机法对发动机故障进行分类。连杆轴承配合间隙故障的台架试验结果证明:相比于传统的分类方法,该方法明显提高了发动机故障分类的准确率。     

高精度阻尼式波美度在线检测装置的研制

牛奶乳浆浓度是生产奶粉过程中,产品质量和节能降耗的主要控制参数.提出了一种浓度在线测量的新方法,阐述了新型低成本牛奶浓度传感器--高精度的阻尼式波美度在线检测装置的研制,根据直流电动机在软机械特性区转速与转矩的关系,建立了浓度与转速的测量模型.经实际运行,证明了该机电一体化装置设计合理,分辨率达到了0.04波美度,高于国外的U型管浓度计的分辨率.     

基于虚拟仪器的串激电机转速测量装置的实现

在工业测控系统中,电动机尤其是交流电动机转速的检测和控制占有很大比重。在以磁电或光电构成的测速系统中,常用的测量方法有3种,分别为T法、M/T法和M法。但对于电动机被封闭的场合则测速比较困难。文中介绍的是应用虚拟仪器技术的一种非接触式转速测量方法及装置,通过从串激电机在转动时感应出的信号中提取出与转速对应的信号,求其频率,然后根据推导出的公式使其转化为转速,从而得出结果。基于该方法的测量装置,速度与串激电机感应出的频率有一一对应关系,因而具有高效率、高精度、非接触测量,且可以及时反映物体的瞬时变化情况等优点。     

A data processing method for determining instantaneous angular speed and acceleration of crankshaft in an aircraft engine–propeller system using a magnetic encoder

This paper presents a method for determining the instantaneous angular speed and instantaneous angular acceleration of the crankshaft in a reciprocating engine and propeller dynamical system from electrical pulse signals generated by a magnetic encoder. The method is based on accurate determination of the measured global mean angular speed and precise values of times when leading edges of individual magnetic teeth pass through the magnetic sensor. Under a steady-state operating condition, a discrete deviation time vs. shaft rotational angle series of uniform interval is obtained and used for accurate determination of the crankshaft speed and acceleration. The proposed method for identifying sub- and super-harmonic oscillations in the instantaneous angular speeds and accelerations is new and efficient. Experiments were carried out on a three-cylinder four-stroke Saito 450R model aircraft engine and a Solo propeller in connection with a 64-teeth Admotec KL2202 magnetic encoder and an HS-4 data acquisition system. Comparisons with an independent data processing scheme indicate that the proposed method yields noise-free instantaneous angular speeds and is superior to the finite difference based methods commonly used in the literature.     

AMT车辆换挡过程中发动机转速控制与试验研究

提出了换挡过程中通过控制断油电磁阀来调节发动机转速的新方法,分析了断油电磁阀对发动机工作特性的影响,制定了断油电磁阀的控制策略,并在装有AMT的某重型载货汽车上进行了试验。试验结果表明,换挡过程中通过控制断油电磁阀来调节发动机的转速,可减小离合器接合时主、被动部分的转速差,改善AMT的换挡品质。     

MC9S12DG128单片机在柴油机电子调速系统中的应用

提出了一种基于16位单片机MC9S12DG128的柴油机数字式电子调速系统,通过单片机对柴油机转速进行PID调节,克服了传统机械式调速系统的诸多缺点。试验结果表明:该控制系统能有效地提高柴油机调速系统的响应速度,改善数字式电子调速系统的动态性能。     

乘用车发动机曲轴位置传感器的工作特性

借助小波对小排量TU5JP4发动机ECU控制转速系统中磁感式曲轴位置传感器进行了转速工作稳定性分析。首先,对曲轴位置传感器测转速失效问题,提出在同一信号轮上布置两个曲轴位置传感器以提高曲轴位置传感器工作稳定性方案。之后,基于小波变换信号突变点检测的融合滤波算法,用该算法对采集到的两组曲轴转速信号作融合滤波处理。结果表明,该算法能有效检测到曲轴转速传感器是否符合失效模式,并能有效滤掉周围噪声和震动,得到曲轴位置传感器采集转速数据稳定性的一种方法。     

Spray characteristics of the rotating fuel injection system of a micro-jet engine

In micro-turbojet engines with less than 350 kW power, it is not easy to find a suitable fuel injector with good spray quality. However, the rotating fuel injection system can potentially provide high atomization quality without the high-pressure fuel pump through the centrifugal forces of the engine shaft. With this motivation, a very small rotating fuel injector with 40 mm diameter is designed for the micro-turbo jet engine. It is directly linked to a high-speed rotational spindle capable of a speed up to 100,000 rpm. The droplet size, velocity, and spray distribution from the PDPA (Phase Doppler Particle Analyzer) system are measured. The spray is also visualized by a high-speed camera. The test results show that the length of liquid column from injection orifice is controlled by the rotational speeds and that SMD (Sauter Mean Diameter) is decreased with increasing rotational speeds. At a rotational speed of 73.3 m/s (35,000 rpm), SMD is lower than 60 μm at the entirety of the measuring space in the case of Type 2 (injection orifice diameter of 1.5 mm) and Type 3 (injection orifice diameter of 2.2 mm). Therefore, conceptually, it is possible to apply this small rotating fuel injection system to the micro-turbojet engine combustor.     

一种大型桁架式结构精密孔协调技术

某型运载火箭发动机机架为大直径桁架式结构,具有刚度弱、焊接变形大的特点。作为连接发动机和箭体传递推力的过渡结构,其上下端面对接孔具有高精度、一致性的协调要求。针对此,提出了一种精密孔协调方案,其利用预拟合和二次拟合法协调底孔包络,采用销孔定位协调二次基准,实现精密孔的整体协调;同时,提出了基于BP神经网络的同轴度预测模型以预测加工后对接孔位置度。经过实际加工验证,该方法能够实现5 m级桁架式结构对接孔的整体协调,保证了对接孔的高精度要求,且该算法能够有效预测并辅助验证位置度检验结果,提高了检验可靠性,为航天大型产品加工整体协调提供了一种思路。     

A Cost-Effective Thickness Measurement Technique for Engine Propellers

This paper describes the design and development of a precision calliper system to measure the surface profile of an outboard marine engine propeller blade. Several instruments that are commonly used for measuring the surface profile of a propeller blade are reviewed in this paper. These include the pitch meter, the profilometer and the computer numerical control coordinate-measuring machine (CNC-CMM). However, the operating practices and availability of different facilities in industry necessitate a more cost-effective approach. An alternative method using a precision calliper system is therefore proposed. Details of the design criteria, principles of operation and the testing and verification of the system are presented. The paper concludes that the precision calliper system is a cost-effective method for measuring the surface profile of a propeller.     

Compensation of rotor imbalance for precision rotation of a planar magnetic bearing rotor

Magnetic bearings provide an alternative for achieving precision rotation. But the rotational accuracy is sensitive to rotor imbalance. The system we study is a planar rotor supported by aerostatic suspension and positioned by a radial magnetic bearing of nanometer precision. We present compensation designs and experiment results for precision rotation about the geometric center and the mass center, respectively. In the former case, the base harmonic component at each sensor output is removed by explicit trigonometric compensation signals that are constructed in real time. In the latter case, a new double-loop compensation design is given. Each compensation loop is similar to that in the former case. The compensation, aided by a variable rotational speed that is changed up and down repeatedly, is shown to push the rotational center to approach the mass center. Once the mass center is reached, the rotor remains to rotate about the mass center at variable rotational speed without transient. Compared with the existing methods, which find the mass center or inertial axis at a fixed rotational speed and rely on exact values of plant parameters, our method may locate the mass center more accurately. Experiment data indicate that the mass center is located with an error of tens of nanometers.     

利用光学系统色偏移进行表面粗糙度检测的方法及结构分析

利用光学方法对表面粗糙度进行检测以其非接触、高精度、无损伤、测量速度快等特点得到了广泛应用.文中介绍了一种利用多色光的轴向色焦点偏移进行表面粗糙度测量的方法,该方法基于共聚焦显微系统的基本思想.文章阐述了该方法的基本原理,并设计了一组光学系统对方法进行分析验证.     

基于快速在线支持张量机的柴油机智能诊断方法

柴油机状态监测信号众多且多为非平稳信号,相互干扰较大且具有非线性和复杂耦合的特征,导致基于向量模式的故障诊断方法难以准确诊断其工作状态。提出一种张量模式下的柴油机智能诊断方法。首先,结合线性支持高阶张量机的学习框架和在线随机梯度下降法的思想,设计带核函数的快速在线支持张量机算法。然后,构建“信号类别×曲轴转角×转速”的三阶张量形式的柴油机状态样本,分别以在线支持向量机、线性支持高阶张量机和快速在线支持张量机三种算法,对某柴油机的失火样本进行故障诊断,以“测试精度”“学习时间”“存储空间”作为评价指标对三种算法进行对比分析。分析结果表明,所设计的快速在线支持张量机算法测试精度较高,学习时间显著降低,所需存储空间很小,解决了超大样本、非线性和高维数据的分类问题,满足了柴油机智能故障诊断的工程应用要求。     

利用瞬时转速诊断电站系统中原动机的失火故障

分析瞬时转速信号在发动机发生失火故障时的波动特性,提出利用发动机瞬时转速诊断电站系统中原动机的失火故障。在提取瞬时转速波形特征参数的基础上,提出基于BP(back propagation)神经网络的故障诊断方法,并对该方法进行实验验证,成功诊断出某型发动机单缸及双缸失火故障,效果明显。     

电机转矩转速测量方法的分析

电机的转矩和转速是最重要的两个参数,对它们的测量必须准确.根据用户提出的测量航空电机具体要求,本文分析了转矩和转速的测量原理,指出了采用应变式和光电式传感器构成测量仪更适合测量大转矩、高转速电机.虽然与传统的测量方法一致,但经过理论分析,得出了这种测量方式机械结构影响测量稳定性的原因,即传动轴受减速器齿轮啮合力作用产生的弯曲应变和结构谐振对测量精度影响最大.本文通过精确的计算,充分地考虑了机械结构对测量稳定性的影响,提出了选择转矩传感器及转速传感器的基本原理与方法.据此,在所研制的电机测量仪中,大大地提高了测量精度,并有效地减小了测量仪的体积和重量,适合航空工业应用.