基于双目立体视觉的转子台振动测试研究

发布时间：2018-04-08 09:49

本文选题：振动测试　切入点：双目立体视觉　出处：《合肥工业大学》2016年硕士论文

【摘要】：振动广泛存在于机械制造、土木工程、航空航天等领域,对结构的安全问题构成一个潜在的威胁,而振动测试是评价其动态性能的有效途径。振动测试在科学研究领域和工程领域都是非常重要的。旋转机械的振动会引起磨损,性能下降以及旋转部件的失效。随着工艺技术和集成电路的发展,传统的接触式传感器如加速度计越来越小,但是传感器的附加质量会改变整个动态系统的特性,同时,对于系统的模态识别来说传感器的放置也是一个关键的问题。这会导致测量结果的不准确。激光技术作为最流行的非接触测量方法被广泛应用于振动测试。尽管该方法具有非接触的特征,但其每次测量范围局限于其照射的范围中,这意味着该方法很难实现全场检测。双目立体视觉方法是基于三角测量原理的,该方法己被应用到各个领域且有望弥补传统传感器的不足。鉴于其非接触、全场、高精度的优点,该方法已吸引广大研究学者的关注。尽管在过去四十年里立体视觉取得了巨大的进步,但三维重建和立体匹配一直是两个研究难题。然而,对于一个测量仪器而言,精度和误差可能是最重要的两个问题。一般的动态场景重建能获得目标的运动趋势,但是振动分析需要更高精度的重建。但是目前关于双目立体视觉的动态重建分析还相对较少。同时,对于传统的技术而言,电涡流传感器只能得到转子轴承系统的横向振动信息。然而,其理论分析模型是基于三维空间的。转子轴在运行过程中必定有一定的轴向窜动,这意味着振动过程中的三维变形。在本文中,选用高速工业相机、采集卡、信号发生器、电动振动试验台、计算机等搭建双目立体视觉系统。实验选用单点跟踪法,即在振动台上贴上圆形特征点,这些特征点可反映振动台的运动状况。分析了由亚像素精度引起的系统的分辨率及误差问题。建立不同的插值模型,且分析了视差精度与系统分辨率的关系。对比了在不同振动幅值和频率的情况下,有亚像素插值和没有亚像素插值时的三维重建结果。系统的世界坐标系精度与视差精度的关系被量化。此外,基于双目立体视觉的方法分析了转子轴承系统在不同转速下的振动情况。且利用该方法观察在不同偏心质量的情况下运动轨迹的变化。对比其在二维空间与三维空间中的不同变化信息。最后,分析了转子轴承系统在不同运转情况下的幅频响应。
[Abstract]:Vibration widely exists in the fields of mechanical manufacturing, civil engineering, aerospace and so on, which pose a potential threat to the safety of structures. Vibration testing is an effective way to evaluate its dynamic performance.Vibration testing is very important in the field of scientific research and engineering.Vibration of rotating machinery can cause wear, performance degradation and failure of rotating parts.With the development of process technology and integrated circuit, traditional contact sensors such as accelerometers are becoming smaller and smaller, but the additional mass of sensors will change the characteristics of the whole dynamic system, at the same time,Sensor placement is also a key issue for modal identification of the system.This can lead to inaccurate measurements.Laser technology is widely used in vibration measurement as the most popular non-contact measurement method.Although the method is non-contact, its measurement range is limited to the range of its exposure, which means that the method is difficult to achieve full-field detection.The binocular stereo vision method is based on the triangulation principle. It has been applied to various fields and is expected to make up for the shortcomings of traditional sensors.Due to its advantages of non-contact, full-field and high accuracy, this method has attracted the attention of many researchers.Although great progress has been made in stereo vision in the past 40 years, 3D reconstruction and stereo matching have been two research problems.However, accuracy and error are probably the two most important problems for a measuring instrument.The general dynamic scene reconstruction can obtain the moving trend of the target, but the vibration analysis needs higher precision reconstruction.But the dynamic reconstruction analysis of binocular stereo vision is relatively rare.At the same time, for the traditional technology, the eddy current sensor can only obtain the transverse vibration information of the rotor bearing system.However, its theoretical analysis model is based on three-dimensional space.There must be a certain axial movement in the rotor shaft, which means the three-dimensional deformation in the vibration process.In this paper, high speed industrial camera, acquisition card, signal generator, electric vibration test bench, computer and so on are selected to build binocular stereo vision system.In the experiment, the single point tracking method is used, that is, the circular characteristic points are affixed to the shaking table, which can reflect the motion of the shaking table.The system resolution and error caused by sub-pixel accuracy are analyzed.Different interpolation models are established and the relationship between parallax accuracy and system resolution is analyzed.The results of 3D reconstruction with sub-pixel interpolation and without sub-pixel interpolation are compared under different vibration amplitudes and frequencies.The relationship between the precision of the world coordinate system and the parallax accuracy of the system is quantified.In addition, the vibration of rotor bearing system at different speeds is analyzed based on binocular stereo vision.This method is used to observe the change of motion trajectory under different eccentric masses.Compare the different information between two dimensional space and three dimensional space.Finally, the amplitude-frequency response of rotor bearing system under different operating conditions is analyzed.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TP391.41;TB53

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