RU2535522C1 - Vibrations measurement method - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: invention relates to measurement equipment. Investigated object is covered with reflective marks of round shape as a test-object. Binary images of this marks and traces of their vibrational blurring are formed. In the absence of vibrations, determined are coordinates of centre of gravity of each mark, and its radius. In the presence of vibration, additional matrix is formed, each fragment of which is a corresponding vibrational blurring trace of mark turned to 90° relative to the mark centre of gravity. For each mark formed are two areas of non-intersection, each of them is an area of connected elements related to vibrational blurring trace of mark, but not related to additional matrix fragment corresponding to it. Coordinates of centres of gravity of non-intersection areas of mark are determined. From centre of gravity of each mark through centre of gravity of its one non-intersection area directed is aiming beam of this mark. Coordinates of two characteristic points of a mark are determined. Half-width of mark vibrational blurring trace is determined as the difference between the distance from centre of gravity of this mark to its first characteristic point. Value of projection of a mark vibration displacement amplitude vector is determined as the difference between half-width of vibrational blurring trace of the mark and its radius. Direction of this projection is determined as tilting angle of the mark aiming beam in image plane.

EFFECT: enlarging functional capabilities.

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Description

The invention relates to measuring equipment, namely to optical methods for measuring vibration parameters, and can be used to monitor the health of nodes and modules of electronic equipment.

A known method of measuring vibration parameters (RF patent 2097710, IPC G01H 1/08. Method of vibration analysis / Usanov D.A., Skripal A.V., Vagarin V.A. - No. 94029365/28; claimed 05.08.1994; publ. . 11.27.1997), which consists in the fact that laser radiation is directed to a vibrating object and a reflected signal is received. The probe and reflected signals are summed, the resulting resulting light signal is converted into electrical signal and the spectrum of this signal is recorded. The signal spectrum is used to judge the amplitudes of the vibration of the object. The disadvantages of this method include the complexity, bulkiness and high cost of equipment, high power consumption, high requirements for the surface quality of the object under study, high requirements for the state of the atmosphere (certain humidity, lack of dust, etc.), in addition, the direction of vibrations is not determined .

A known method of measuring vibration parameters (RF patent 2061242, IPC G01P 15/08, G01H 1/00. Three-component piezoelectric vibration accelerometer with one sensitive element / Kobyakov IB - No. 94019569/28; claimed. 27.05.1994; publ. 27.05. 1996), which consists in the fact that a piezoelectric three-component vibration acceleration sensor containing one sensing element is installed on a vibrating object. The disadvantages of this method include the fact that the contact piezosensitive vibration sensor is a source of measurement error, if its weight and dimensions are comparable with the corresponding parameters of the vibrating object. If, for example, it is required to measure the amplitudes and directions of vibrations of the assembly of electronic equipment mounted on a printed circuit board, then the error introduced by piezoceramic products in the form of rectangular parallelepipeds with a square base of about 10 mm and a height comparable to the size of the base will be very significant. In addition, in printed circuit assemblies, as a rule, it is required to measure vibrations simultaneously at many points of these assemblies. Installing a large number of vibration sensors with cumbersome hinged mounting can increase the introduced error to unacceptable values.

The closest in technical essence is a method for measuring vibration parameters (RF patent 2395792, IPC G01H 9/00. Method for measuring vibration parameters of an object / Pronin SP, Zryumov EA, Yudenkov AV - No. 2009125845/28; Dec. 06.07.2009; publ. 07.27.2010), consisting in the fact that a stencil is fixed on a vibrating object with groups of parallel strokes of various widths deposited on it having a common axis of symmetry, with a distance between the strokes in the group equal to twice the stroke width. Using a video camera, a stencil image is formed on a computer monitor screen with vibration blur and fixing the corresponding frame rate of the video camera equal to the vibration frequency of the object. After that, zero contrast is recorded in the still image of the stencil in the group of the widest strokes. The stroke width in this group judges the magnitude of the vibration displacement of the object and, therefore, the modulus of the amplitude vector of the vibration displacement of this object. The disadvantages of this method include the fact that measurements are possible only if the direction of the vector of the amplitude of the vibrational displacement of the object is perpendicular to the axis of symmetry of the strokes. If this condition is not fulfilled, then the zero contrast in the group of strokes does not carry information about the module of the vector of the amplitude of the vibrational displacement of the object. That is, it is impossible to measure the direction of the amplitude vector of the vibrational displacement of the object in this way, and the module of this vector can be measured only if its direction is known in advance. The number of groups of strokes on the stencil should be equal to the required overlap coefficient over the dynamic range of the module of the vector of the amplitude of the vibrational displacement of the object. Therefore, with increasing requirements for measurement accuracy, the stencil becomes more complicated, its mass and overall dimensions grow. And this, in turn, reduces the accuracy of measurements.

The technical result of the proposed method for measuring vibrations is the expansion of the possibilities of measuring the vibration parameters of the investigated object due to non-contact three-coordinate measurement of the modules and directions of the vibration displacement amplitude vectors of several selected points of the studied object at the same time.

The proposed method for measuring vibrations is based on the fact that reflective marks in the form of round dots are applied to the test object as a test object in the required places, binary raster images of these marks and traces of their vibrational blur are formed. In the absence of vibration, the coordinates of the center of gravity of each mark are determined, its area and its radius are determined by the area. In the presence of vibrations, a binary raster image of traces of vibrational blur marks is formed.

The projection of the amplitude vector of the vibrational displacement of each mark on the direction perpendicular to the image plane is directly proportional to the increment of the radius of the mark due to its vibrational blur, that is, the difference between the half-width of the trace of vibrational blur of the mark and its radius determined in the absence of vibration. The direction of the projection of the vector of the amplitude of the vibratory movement of the mark on the image plane determines the angular position of the trace of vibration blur of the mark. The magnitude of this projection is directly proportional to the difference between the distance from the center of gravity of the mark to the boundary of the trace of its vibrational blur in the direction of vibration and the half-width of this trace.

To determine the angular position of the trace of vibrational blur of each mark, the half-width of this trace, the distance from the center of gravity of the mark to the border of the trace in the direction of vibration, an additional matrix is formed, each fragment of which is a trace of vibrational blur of the corresponding mark rotated 90 ° relative to the center of gravity of this mark. For each label, two non-intersection regions are formed, each of which is a region of related elements belonging to the trace of vibrational blur of the label but not belonging to the corresponding fragment of the additional matrix, and the coordinates of the centers of gravity of the non-intersection regions are determined. Of the two non-intersection areas corresponding to the mark, a guide is selected. For the guide region of non-intersection of the label, one of its non-intersection regions is taken, the center of gravity of which exceeds the center of gravity of the label. In the case of equality of these abscissas for the guide region of non-intersection is taken one whose ordinate of the center of gravity of which exceeds the ordinate of the center of gravity of the label. From the center of gravity of the mark through the center of gravity of its guide region of non-intersection spend guide beam mark. The coordinates of the first and second characteristic points of the label are determined. The first characteristic point of the mark is the intersection point of the guide beam of this mark with the boundary element of the corresponding fragment of the additional matrix. The second characteristic point of the mark is the intersection point of the guide beam of this mark with the boundary element of the trace of its vibrational blur. The half-width of the trace of vibrational blur of the mark is defined as the distance from the center of gravity of the mark to its first characteristic point. The magnitude of the projection of the amplitude vector of the vibration displacement on the direction perpendicular to the image plane is determined as the difference between the half-width of the trace of the vibration blur of the mark and the radius of this mark. The direction of the projection of the vector of the amplitude of the vibratory movement of the mark on the image plane is determined as the angle of inclination of its guide beam. The value of this projection is defined as the difference between the distance from the center of gravity of the mark to the second characteristic point of this mark and the half-width of the trace of its vibrational blur. As a result, the problem of contactless three-coordinate measurement of the modules and directions of the vectors of the amplitude of vibrational displacement of several selected points of the object under study is solved simultaneously.

Figure 1 shows the structure of the trace of vibrational blur marks. Figure 2 presents a mutually orthogonal system of traces of vibrational blur marks and the corresponding elements of the additional matrix. Figure 3 presents the structure of the areas of non-intersection labels. Figure 4 shows the structure of the traces of vibrational blur marks with the centers of gravity of the areas of non-intersection marks marked on them. Figure 5 presents the structure of the traces of vibrational blur marks with the centers of gravity of the areas of non-intersection of marks marked on them, the centers of gravity of the marks and guide beams of the marks. Figure 6 shows the structure of the traces of vibrational blur marks with the centers of gravity of the marks indicated on them, guide beams of the marks and the second characteristic points of the marks. Figure 7 shows the structure of the fragments of the additional matrix with the centers of gravity of the marks marked on them, the guiding rays of the marks and the first characteristic points of the marks.

The non-contact three-coordinate measurement of the modules and directions of the vibration displacement amplitude vectors of several selected points of the studied object is simultaneously achieved due to the fact that the motion of any point of the studied object is described in a three-dimensional coordinate system in which the motion vector characterizes the magnitude and direction of the vibration. The projections of the amplitude vector of vibration displacement on the coordinate axis uniquely determine the module of this vector and its direction in a given coordinate system.

To register the vibrations, several sections of the object under study are selected, each of which is applied with reflective round marks. Form a binary image of these labels. In the absence of vibration, the coordinates of the centers of gravity of the marks are determined from this image, their area and the radii of the marks are calculated from these areas. In the presence of vibrations, the location of the marks in the direction of the vibrations in the image plane, as well as in the direction perpendicular to this plane, is modulated. As a result, an image of traces of vibrational blur marks is formed. A flat image of the trace of vibrational blur of a label carries complete information about the projections of the vector of the amplitude of vibrational displacement of this label onto the coordinate axes in three-dimensional space, that is, about the magnitude and direction of this vector. If we assume that in the Cartesian coordinate system the image plane is “X0Y”, and the Z axis is perpendicular to the image plane, then the module of the vector of the amplitude of the vibratory movement of the label:

$$A^k=\sqrt{(A_z^k)+{(A_{xy}^k)}^2}\left(\text{one}\right)$$

- проекция вектора амплитуды виброперемещения k-й метки на направление, перпендикулярное плоскости изображения; $$A_{xy}^k$$

- проекция вектора амплитуды виброперемещения k-й метки на плоскость изображения.where k is the serial number of the label; And ^k is the modulus of the amplitude vector of the vibration displacement of the kth mark; $$A_z^k$$

- the projection of the amplitude vector of the vibrational displacement of the kth mark on the direction perpendicular to the image plane; $$A_{xy}^k$$

- the projection of the amplitude vector of the vibration displacement of the kth mark on the image plane.

The proposed method allows to trace the size and direction of the projection of the vector of the amplitude of the vibrational displacement of the mark in the image plane and the projection of this vector on the direction perpendicular to this plane, following the vibrational blur of the mark. The process of determining the components of the amplitude vector of vibrational displacement of the mark along the trace of its vibrational blur can be divided into several stages. The first of these is the imaging of traces of vibrational blur marks. Of the variety of readers, the most common are television-type devices using charge-coupled devices, on the targets of which the accumulated charge is proportional to the illumination of the target matrix cell and the time of exposure to light on this cell. Thus, already on the target of the reader during the accumulation of a charge equal to approximately the period of repetition of reading frames, the entire trace or its part is formed. It is quite obvious that the entire trace at a vibration frequency less than the frame read rate on the target of the reader cannot be fixed. Therefore, in this case, the complete trace of the vibratory blur of the label should be recorded for several frames and stored for the time necessary for further processing as a fragment of the matrix of traces of vibratory blur of the labels, the size of which coincides with the size of the matrix of the reader. For example: with a vibration frequency of 1 Hz and a frame frequency of 50 Hz, it is necessary to accumulate a charge over a period of more than 1 second, that is, over more than 50 frames. With a vibration frequency of more than 50 Hz, one reading frame is required. The matrix of traces of vibrational blur of labels consists of binary elements. Therefore, the logical level of “1”, corresponding to the element of the trace of vibrational blur of the label, upon subsequent access to the same cell is confirmed and stored for the time of subsequent processing. The structure of the trace of vibration blur marks presented on figure 1.

To determine the projections of the vectors of amplitudes of vibrational displacement of the labels on the image plane A _xy and on the direction perpendicular to this plane, A _z form an additional matrix by rotating ninety degrees clockwise of each fragment of the matrix of traces of vibrational blur of the marks relative to the center of gravity of the corresponding mark. The matrix of traces of vibrational blur marks and an additional matrix form a mutually orthogonal system (figure 2). The sequence of actions with the matrix of traces of vibrational blur marks and additional matrix is as follows. Non-intersection regions are formed, defined as regions of related elements that belong to a fragment of the matrix of traces of vibrational blur of labels, but do not belong to the corresponding fragment of the additional matrix. As a result of this action, two areas of non-intersection of this mark are formed within the trace of vibrational blur of each mark. The coordinates of the center of gravity of each non-intersection area of each label are determined (FIG. 3).

The guiding non-intersection region of each mark is determined. The region of non-intersection of the mark, the abscissa of the center of gravity of which exceeds the abscissa of the center of gravity of the mark, is taken as a guide. In case of equality of these abscissas, the region of non-intersection of the mark is taken as a guide, the ordinate of the center of gravity of which exceeds the ordinate of the center of gravity of the mark. Determine the angle of the projection of the vector of the amplitude of the vibrational displacement of each label on the image plane with respect to the coordinate system "X0Y" (figure 4):

, $${\varphi }^k=arctg\frac{y_{02}^k-y_0^k}{x_{02}^k-x_0^k}\left(\text{2}\right)$$

,

и $$y_0^k$$

- ординаты центров тяжести направляющей области пересечения k-й метки и самой этой метки соответственно; $$x_{02}^k$$

и $$x_0^k$$

- абсциссы центров тяжести направляющей области пересечения k-й метки и самой этой метки соответственно.where k is the serial number of the label; φ ^k is the angle of the projection of the vector of the amplitude of the vibrational displacement of the kth mark with respect to the coordinate system "X0Y"; $$y_{02}^k$$

and $$y_0^k$$

- ordinates of the centers of gravity of the guide region of the intersection of the kth mark and this mark itself, respectively; $$x_{02}^k$$

and $$x_0^k$$

- abscissas of the centers of gravity of the guide region of the intersection of the kth mark and this mark itself, respectively.

From the center of gravity of each kth mark through the center of gravity of its guiding non-intersection region, a guiding ray of the kth mark is drawn (Fig. 5), the coordinates of the point of intersection of the guiding beam of the kth mark and the boundary of the track of its vibration blur n ^k are recorded (Fig. 6) ) as the coordinates of the second characteristic point of the kth mark. The distance from the center of gravity of the k-th label boundary to track its vibratory blur in the direction of vibration is defined as the distance from the center of gravity of the k-th label to its second characteristic point n ^k:

. $$l_{xy}^k\sqrt{{(y_n^k-y_0^k)}^2+{(x_n^k-x_0^k)}^2}\left(\text{3}\right)$$

.

The coordinates of the point of intersection of the guiding ray of the kth mark and the boundary of the corresponding fragment of the additional matrix h ^k (Fig. 7) are fixed as the coordinates of the first characteristic point of the kth mark. The half-width of the trace of vibrational blur of the kth mark δ ^k is defined as the distance from the center of gravity of the kth mark to its first characteristic point h ^k :

. $${\delta }^k=\sqrt{{(y_n^k-y_0^k)}^2+{(x_n^k-x_0^k)}^2}\left(\text{four}\right)$$

.

:The difference between the distance from the center of gravity of the k-th mark to the boundary of the trace of its vibrational blur in the direction of vibration and the half-width of the trace of its vibrational blur is calculated $$L_{xy}^k$$

:

. $$L_{xy}^k=l_{xy}^k-{\delta }^k\left(\text{5}\right)$$

.

между полушириной следа вибрационного размытия k-й метки δ^k и ее радиусом r^k:The difference is calculated $$L_z^k$$

between the half-width of the trace of vibrational blur of the kth mark δ ^k and its radius r ^k :

. $$L_z^k={\delta }^k-r^k\left(\text{6}\right)$$

.

:The magnitude of the projection of the amplitude vector of the vibrational displacement of the kth mark on the image plane is calculated $$A_{xy}^k$$

:

, $$A_{xy}^k=y^k\cdot L_{xy}^k\left(\text{7}\right)$$

,

where γ ^k is the scale factor associated with the properties of the optical system for the kth mark.

определяют по формуле:Abscissa of the vector of the amplitude of vibration displacement of the kth mark $$A_x^k$$

determined by the formula:

. $$A_x^k=A_{xy}^k\cos {\varphi }^k\left(\text{8}\right)$$

.

определяют по формуле:The ordinate of the vibration amplitude vector of the kth mark $$A_y^k$$

determined by the formula:

. $$A_y^k=A_{xy}^{k}Sin{\varphi }^k\left(\text{9}\right)$$

.

:The magnitude of the projection of the amplitude vector of the vibrational displacement of the kth mark on the direction perpendicular to the image plane is calculated $$A_z^k$$

:

,где R^k - масштабный коэффициент, связанный со свойствами оптической системы при расфокусировке изображения для k-й метки. $$A_z^k=R^k\cdot L_z^k\left(\text{10}\right)$$

, where R ^k is the scale factor associated with the properties of the optical system when the image is defocused for the kth mark.

является аппликатой вектора амплитуды виброперемещения k-й метки.The magnitude of the projection of the amplitude vector of the vibrational displacement of the kth mark on the direction perpendicular to the image plane $$A_z^k$$

is the applicate of the vibration amplitude vector of the kth mark.

By the formula (1), the modulus of the vector of the amplitude of vibrational displacement of each kth mark is determined.

Thus, three projections, the modulus and the direction of the vibrational amplitude vector of each kth mark are determined.

Claims (1)

A method for measuring vibrations, including attaching a test object to a test object and registering an image of this test object with vibration blur, characterized in that reflective marks in the form of round points are applied to the studied object as a test object, binary images are formed of these marks and traces of their vibrational blur, in the absence of vibrations, determine the coordinates of the centers of gravity of the marks and their radii, in the presence of vibrations form an additional matrix, each fragment of which oh is the trace of vibrational blur of the corresponding mark rotated 90 ° relative to the center of gravity of this mark, for each mark two non-intersection regions are formed, each of which is a region of related elements that belong to the trace of vibrational blur of the mark but do not belong to the corresponding fragment of the additional matrix , determine the coordinates of the centers of gravity of the areas of non-intersection, from the center of gravity of the label through the center of gravity of one of its areas of non-intersection spend guides ith mark beam, two characteristic mark points are defined, the first of which is the intersection point of the mark guiding beam and the boundary of the corresponding fragment of the additional matrix, and the second is the intersection point of the mark guiding beam and the boundary of the track of its vibration blur, the half-width of the mark vibration blur track is determined as the distance from the center of gravity of this mark to its first characteristic point, the magnitude of the projection of the vector of the amplitude of the vibrodisplacement of the mark on the direction perpendicular to image bones are defined as the difference between the half-width of the trace of the vibrational blur of this mark and its radius, the projection of the vector of the amplitude vector of the vibro-displacement of the mark on the image plane is determined as the difference between the distance from the center of gravity of this mark to its second characteristic point and the half-width of the trace of its vibration blur, the direction of this projections are defined as the angle of inclination of the guide beam of the mark in the image plane.

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