Research on Instantaneous Angular Speed Signal Separation Method for Planetary Gear Fault Diagnosis

Planetary gear train is a critical transmission component in large equipment such as helicopters and wind turbines. Conducting damage perception of planetary gear trains is of great significance for the safe operation of equipment. Existing methods for damage perception of planetary gear trains mainly rely on linear vibration analysis. However, these methods based on linear vibration signal analysis face challenges such as rich vibration sources, complex signal coupling and modulation mechanisms, significant influence of transmission paths, and difficulties in separating damage information. This paper proposes a method for separating instantaneous angular speed (IAS) signals for planetary gear fault diagnosis. Firstly, this method obtains encoder pulse signals through a built-in encoder. Based on this, it calculates the IAS signals using the Hilbert transform, and obtains the time-domain synchronous average signal of the IAS of the planetary gear through time-domain synchronous averaging technology, thus realizing the fault diagnosis of the planetary gear train. Experimental results validate the effectiveness of the calculated IAS signals, demonstrating that the time-domain synchronous averaging technology can highlight impact characteristics, effectively separate and extract fault impacts, greatly reduce the testing cost of experiments, and provide an effective tool for the fault diagnosis of planetary gear trains.

Electrochemical nucleation and growth of aluminum nanoparticles and leaf-like flat microstructures from reline deep eutectic solvent: Effect of temperature and angular speed of working electrode

The main objective of this work was to use reline deep eutectic solvent,containing Al(III)ions,for the electrochemical study of the nucleation and growth of aluminum onto a glassy carbon electrode at different temperatures and angular speeds(ω)of the working electrode.In order to fulfill this,electrochemical and surface characterization techniques were used.It was found that as temperature increased,the onset of the Al(III)DES reduction occurred at less negative potentials while the current peak of the voltammograms increased.These indicate that Al deposition thermodynamics and kinetics were favored.Practically,no anodic current was detected due to Al passivation by Al(OH)_(3)(s)andγ-Al_(2)O_(3)(s).Atω=0 r/min,the Al deposition chronoamperograms were analyzed by a theoretical model comprising Al 3D diffusion-controlled nucleation and growth and residual water reduction.However,those recorded at different angular speeds were analyzed with a theoretical model where adsorption−desorption and diffusion-controlled nucleation−growth occurred simultaneously.The deposits were characterized by SEM,EDX,XPS and XRD.Atω=0 r/min,formation of well distributed nanoparticles((78.1±9.5)nm)was observed,while atω=900 r/min the deposit was formed by multiple 10μm diameter leaf-like flat microstructures,composed by Al,Al(OH)_(3)(s)andγ-A2O3(s).

Air flow patterns and noise analysis inside high speed angular contact ball bearings

The vortex formed around the rolling ball and the high pressure region formed around the ball-raceway contact zone are the principle factors that barricades the lubricant entering the bearing cavity, and further causes improper lubrication. The investigation of the air phase flow inside the bearing cavity is essential for the optimization of the oil-air two-phase lubrication method. With the revolutionary reference frame describing the bearing motion, a highly precise air phase flow model inside the angular contact ball bearing cavity was build up. Comprehensive factors such as bearing revolution, ball rotation, and cage structure were considered to investigate the influences on the air phase flow and heat transfer efficiency. The aerodynamic noise was also analyzed. The result shows that the ball spinning leads to the pressure rise and uneven pressure distribution. The air phase velocity, pressure and cage heat transfer efficiency increase as the revolving speed increases. The operating noise is largely due to the impact of the high speed external flow on the bearing. When the center of the oil-air outlet fixes near the inner ring, the aerodynamic noise is reduced. The position near the inner ring on the bigger axial side is the ideal position to fix the lubricating device for the angular contact ball bearing.

Biased retro-proportional navigation law for interception of high-speed targets with angular constraint

A new guidance law, called biased retro proportional navigation(BRPN), is proposed. The guidance law is designed to intercept high-speed targets with angular constraint, which can be used for ballistic target interception. BRPN guidance law is defined, and the exact time-varying bias for a required impact angle is derived. Furthermore, the simulation results(trajectory, variation of navigation ratio, capture region, etc) are compared with those of biased proportional navigation(BPN), proportional navigation and retro-proportional navigation. The results show that,at the cost of a higher intercept time, BRPN demands lower terminal lateral acceleration and has larger capture region compared to BPN.

Detection of kinematics parameters of index finger movement with high-speed video camera

Synergic movement of finger's joints provides human hand tremendous dexterities,and the detection of kinematics parameters is critical to describe and evaluate the kinesiology functions of the fingers.The present work is the attempt to investigate how the angular velocity and angular acceleration of the joints of index finger vary with respect to time during conducting a motor task.A high-speed video camera has been employed to visually record the movement of index finger,and miniaturized(5-mm diameter) reflective markers have affixed to the subject's index finger on the side close to thumb and dorsum of thumb at different joint landmarks.Captured images have been reviewed frame by frame to get the coordinate values of each joint,and the angular displacements,angular velocities and angular acceleration can be obtained with triangle function.The experiment results show that the methods here can detect the kinematics parameters of index finger joints during moving,and can be a valid route to study the motor function of index finger.

Novel scheme of high precision inertial measurement for high-speed rotating carriers

In order to satisfy the requirement of high precision measurement in a high dynamic environment, a kind of gyro aided multi-accelerometer inertial measurement unit （GAMA-IMU） with six accelerometers and two gyros （6A2G） was proposed in this paper. The available configurations have the problem of low measurement precision In a high dynamic environment due to channel coupling. The three channels were decoupled when calculating the angular velocity in the proposed configuration. The yawing and pitching angular velocity were directly measured by gyros, while only the rolling angular velocity was obtained by the GAMA-IMU indirectly from the rolling angular acceleration and quadratic component of rolling angular velocity. Then a single channel rolling angular velocity calculation model was established and the extended Kalman filter （EKF） was used to do state esti- mation. Simulations were carried out and results indicated that the calculation precision of the proposed 6A2G configuration could meet the demand of high precision measurement for a high-speed rotating carrier.

机翼翼尖涡与平尾翼尖涡的相互作用研究

飞机尾涡的发展与同跑道降落后机的飞行安全及机场起降效率密切相关。尾涡近场特性主要决定了着陆阶段飞机的尾涡强度。以A320飞机简化缩比模型为研究对象,在1 m×1 m低速水洞中开展了尾涡近场形态流动显示实验。研究结果表明:平尾涡在拖出过程中围绕翼尖涡旋转,不同流向站位的旋转角速度存在差异。对比模拟结果发现:平尾涡绕翼尖涡的旋转角速度与实验结果基本吻合,说明不同雷诺数下涡对发展在相对位置旋转角速度特性方面具有一定相似性。

平转施工桥梁转体角速度及角加速度合理取值分析

关于水平转体施工桥梁的转体角速度限值问题存在较大的争议,现有标准提出的0.01~0.02 rad/min的平转角速度限值偏于保守,造成部分转体桥无法在正常的铁路天窗时间内完成转体,而一些工程实际采用的转速大幅超过现有标准,但并未对结构安全造成任何影响。本文对转体角速度和角加速度与结构效应的对应关系进行理论分析,对国内相关研究成果进行归纳总结,并结合襄北编组站大桥的模型试验数据,按照转体悬臂长度提出转体角速度和角加速度合理取值范围。推荐取值为:悬臂长度不大于40 m时,角速度宜控制在0.05 rad/min以下;悬臂长度大于80 m时,角速度宜控制在0.025 rad/min以下;悬臂长度在40~80 m时,转体角速度的上限值可内插取值;转体角加速度宜控制在2.2×10^(-5)~4.2×10^(-5)rad/s^(2)。

跨铁路T构桥水平转体施工阶段主梁与桥墩力学特性研究

为了研究T构桥在水平转体施工过程中主梁和桥墩的力学特性,以大同某跨铁路T构转体桥为依托,采用有限元软件Ansys建立了上转盘以上结构的实体模型,分析了主梁和桥墩在不同转动角速度和转动角加速度下的应力变化规律,确定了T构桥转体时转动角速度和转动角加速度的可行范围。结果表明:主梁应力对称分布,根部截面应力最大,桥墩应力则在与主梁及上转盘连接处截面最大;T构桥匀速转动时,主梁和桥墩的应力与转动角速度的平方成正比,当转动角速度为0.02 rad/min时,主梁最大应力为0.5 Pa,桥墩最大应力为0.08 Pa,转动角速度对T构桥的影响较小;T构桥加速转动时,主梁和桥墩的应力与转动角加速度成正比,当转动角加速度为1×10^(-3)rad/s^(2)时,主梁最大应力为0.16 MPa,桥墩最大剪应力为0.14 MPa。在T构桥实际转体施工中,转动角速度为0.017 rad/min,转动角加速度最大为8×10^(-4)rad/s^(2),最终用时100 min平稳顺利完成转体。

基于自适应多周期微分均值的轴承故障诊断

为解决瞬时角速度信号(instantaneous angular speed,简称IAS)中轴承故障特征微弱的难题,提出一种自适应多周期微分均值(adaptive multi-period differential mean,简称AMPDM)方法。首先,基于微分技术不受幅值干扰的优势,结合多周期均值的累积特性,提出一种多周期微分均值技术对IAS信号中轴承故障特征进行增强,进而抑制编码器安装误差、IAS估计误差和测量噪声等干扰分量;其次,采用一种改进诊断特征(improved diagnosis feature,简称IDF)指标评估在不同周期数K下增强信号中包含轴承故障信息的丰富性,并确定IDF值最大时对应的优化周期数Kop;最后,通过包络阶次谱分析揭示轴承故障特征。仿真和实验结果表明,AMPDM技术可有效增强IAS信号中轴承故障特征,并与可调整多点优化最小熵反卷积、倒谱预白化和快速谱相关3种算法对比,验证了所提方法的优势和有效性。

基于磁编码器和窄带解调的太阳轮故障检测

绝对式磁编码器具有价格低、安装方便等优势,适合于工程应用,但在低转速工况下其角度信号受测量误差的影响较大,需要对角度信号进行拟合以消除测量误差带来的干扰。传统的分段拟合方法在分段点处易出现不连续现象,角度信号的不连续导致由其计算的瞬时角速度(instantaneous angular speed,简称IAS)信号中出现虚假冲击,并对基于IAS信号的故障特征提取造成干扰。针对此问题,提出一种基于绝对式磁编码器IAS估计和窄带解调的太阳轮故障检测方法。首先,为保证IAS信号的连续性与平滑性,提出基于最小二乘拟合与5次Hermite插值的方法,实现了对IAS信号的拟合估计和平滑处理;其次,结合窄带解调技术实现了对行星齿轮减速器太阳轮故障特征的有效提取;最后,通过对正常与故障太阳轮的绝对式磁编码器信号分析对比,验证了所提方法的有效性。

平均降采样多周期微分均值的旋转部件故障特征增强方法

为解决编码器的瞬时角速度(Instantaneous Angular Speed,IAS)信号中旋转部件故障特征微弱的难题,本文提出一种平均降采样多周期微分均值(Average Down⁃Sampling Multi⁃period Differential Means,ADSMPDM)的故障特征增强方法。基于IAS信号的估计特性,开展了IAS信号的平均降采样研究,验证了平均降采样具有抑制随机噪声的特性;基于平均降采样抑制随机噪声特性、降低计算成本和减小存储空间的优势,结合多周期微分均值的累积特性,提出一种ADSMPDM算法对原始IAS信号中的旋转部件故障分量进行增强处理;通过阶次谱分析揭示故障特征。采用仿真数据和实验数据进行验证分析,并与快速谱峭度、可调整多点优化最小熵反卷积、离散随机分离和谱幅值调制算法进行对比,验证了ADSMPDM算法增强旋转部件故障特征的有效性和优势。

基于IAS信号自适应窄带解调的RV减速器摆线轮故障特征提取

RV(rotary vector)减速器广泛应用于工业机器人,研究其关键零部件的故障检测方法具有重要意义。由于RV减速器结构复杂、摆线轮转速低、故障冲击较弱等问题,造成摆线轮故障特征难以用常规振动分析方法提取。针对上述问题,提出一种基于瞬时角速度信号自适应窄带解调的RV减速器摆线轮故障特征提取方法。首先对编码器角度信号进行采集,然后使用向前差分法获得瞬时角速度信号,在此基础上,使用角域同步平均提取摆线轮周期相关同步分量,消除非同步干扰,并通过构建边带信噪比指标选取故障信息丰富的啮合谐波频带进行带通滤波,最后对滤波后的信号进行窄带解调,实现对RV减速器摆线轮的故障特征提取。试验结果表明,该方法可以有效地提取RV减速器摆线轮故障特征,且自适应实现优化带宽选择。

基于编码器信号自适应MOMEDA的太阳轮故障检测

针对行星减速器太阳轮故障检测问题,提出了一种基于改进自适应多点最优最小熵反褶积(multipoint optimal minimum entropy deconvolution adjusted,简称MOMEDA)的太阳轮故障检测方法。首先,基于编码器信号传递路径短、与动力学直接相关的优势,结合传动参数,计算得到故障特征周期,确定故障周期搜索区间及步长;其次,利用谱负熵最大化原则自适应确定优化滤波器长度,并得到解卷积后的信号;最后,采用包络谱分析揭示太阳轮齿根裂纹故障特征。通过仿真和实测数据分析,验证了所提方法的有效性。

基于瞬时角速度信号增强的RV减速器行星齿轮局部故障检测

针对旋转矢量(rotary vector, RV)减速器多源耦合严重,行星齿轮局部故障所引起的冲击易被其他干扰分量所淹没,故障特征提取困难的问题,结合编码器信号的优势提出了一种基于自适应最大二阶循环平稳盲解卷积(adaptive maximum second order cyclostationarity blind deconvolution, ACYCBD)的RV减速器行星齿轮局部故障检测方法。首先,拾取伺服电机内置光编码器信号,并利用向前差分计算获得瞬时角速度(instantaneous angular speed, IAS)信号;然后,依据特征评价指标(characteristic evaluation indicator, CEI)最大化原则自适应确定ACYCBD优化滤波器长度,并对IAS信号进行增强;最后,通过识别时域中与故障冲击周期相匹配的理论齿数实现RV减速器故障检测。通过试验数据分析,并将所提方法与现有的稀疏低秩分解算法和增强CYCBD算法对比,验证了所提方法的有效性。

双支撑转轴、倾转角速度控制恒流量连续浇注技术的应用

有色金属连续铸造对熔体出口位置、流量和炉体的稳定性有较高的要求,因此针对小截面杆坯连续铸造,设计了双支撑转轴结构的炉体,提出了控制炉体倾转角速度恒流量浇注的技术方案,建立了恒流量铸造的数学模型。据此设计了相应的 PLC控制程序,提高了有色金属连续铸造小截面坯杆截面高度尺寸一致性和炉体的稳定性。

高速脂润滑角接触球轴承结构参数的设计研究

高速脂润滑角接触球轴承在机床和加工中心等领域应用广泛。为实现国产化代替,通过建立高速脂润滑角接触球轴承拟动力学模型,以离心力、轴向刚度、旋滚比、接触应力为目标函数,对轴承接触角、沟曲率系数、滚动体直径、滚动体数量和材料等结构参数进行设计研究,并对设计后的H7020-2RZ轴承进行温升性能和极限转速试验,结果表明满足要求。

高速角接触球轴承保持架受力分析

介绍了高速角接触球轴承启动过程中球对保持架的冲击力、保持架在离心力作用下产生的环向拉应力以及轴承运转中因球速变化引起的球与保持架之间作用力的计算方法。并以某型号轴承A为例进行了保持架强度计算,根据计算结果选择了合适的保持架材料。

4.5 m×3.5 m低速风洞动导数试验技术研究

动导数是飞行器操稳特性分析、控制律设计过程中的关键参数。为满足大型飞行器研制对高精度动导数数据的获取需求,中国航空工业空气动力研究院基于4.5 m×3.5 m低速风洞开发了具备5种振荡试验能力的低速动导数试验系统。该试验系统利用伺服液压摆动马达和伺服液压缸作为运动的驱动元件,经过伺服阀的控制直接产生任意波形的强迫运动,具有运动传递间隙小、运动控制精度高、系统自动化程度高等特点。可实现2.5 m量级模型的动导数试验,风速范围30~60 m/s,迎角范围-36°~36°,侧滑角范围-40°~40°。利用动态标模及某翼身融合布局模型进行了动导数验证试验,结果表明该系统获得的动导数数据规律合理,数据精度在3%以内,可为大型飞行器研制提供高质量的动导数试验数据。

高速精密机床主轴轴承振动特性分析

主轴轴承作为高速精密机床主轴的核心支承部件,其振动性能对整个机床的加工精度、效率至关重要。然而,因高速工况下轴承设计不足,难以有效解决因振动引起的加工精度下降及设备寿命缩短等问题。以某特定型号的角接触球轴承为研究对象,建立滚动轴承动力学分析模型,开展轴承结构参数和工况条件对高速精密机床主轴轴承的振动特性研究,并设计搭建试验台,进行轴承的振动试验验证。结果表明:增大内圈沟曲率半径系数会增大振动加速度级,增大外圈沟曲率半径系数会使其减小;外圈沟曲率半径系数对轴承振动加速度级变化的影响更显著;通过设定合理的径向载荷、轴向载荷及内圈转速范围,可降低角接触球轴承的振动加速度值;试验结果表明轴承加速度级的理论分析与试验值之间的误差为8.33%,验证了仿真模型的精确性。