JP4333055B2 - Deformation measurement system and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for measuring relative deformation between two parts of an object such as an automobile.
[0002]
[Prior art]
As a method for actually measuring the deformation of each part of the vehicle in the running state, there is known a method of attaching an acceleration pickup to each part of the vehicle and analyzing their output signals. In this method, the acceleration at each point obtained by the acceleration pickup is integrated twice to obtain the displacement at each point.
[0003]
In addition, a method has been proposed in which a combination of a ring-shaped displacement sensor and a wire is attached to the vehicle body and the distance between two points is measured (Mazda Motor Corporation, Japan Society for Automotive Engineers 2000 Autumn Meeting).
[0004]
There is also known a method of analyzing deformation of each part of the vehicle by stereo pair matching using a CCD camera. In this method, the target mark is marked on the vehicle, and the target mark is photographed by two CCD cameras attached to the vehicle, and the mark is obtained by the principle of trigonometry from the position of the target mark in the photographed image of each camera. Is calculated. The deformation can be obtained by comparing the position of the same target mark when the vehicle is stopped and the position when the vehicle is running.
[0005]
[Problems to be solved by the invention]
The method using an accelerometer is an effective method in a bench test using a chassis dynamo or the like, but is difficult to apply to an actual running test performed by actually running on a test course or the like. The reason is that when the vehicle is traveling, the acceleration detected by the acceleration pickup includes not only the component due to vehicle body deformation but also the acceleration component of the entire vehicle due to traveling, and it is difficult to separate them. is there.
[0006]
Further, the above method using a ring-shaped displacement sensor has a problem that it is difficult to obtain an accurate displacement because the wire resonates during actual traveling.
[0007]
Stereo pair matching using a CCD camera, etc. can obtain deformation with high accuracy even in an actual running test, but the problem is that calibration of the camera before measurement is complicated and a lot of time is required for image processing. There is. Particularly in image processing, for example, in stereo images, it is necessary to identify the same target mark in the right image and the left image, and to perform trigonometric calculations from them. Will increase. Furthermore, when trying to analyze vibrational deformation behavior with a high frequency, it is necessary to perform analytical calculations on stereo images taken at a high frame rate, and performing this in real time is extremely computationally intensive. A computer is required, and real-time processing has been very difficult in practice.
[0008]
The present invention has been made in view of such problems, and the deformation of an object such as a vehicle is accurately obtained even when the object itself moves as a whole (such as when the vehicle is in an actual running state). It is another object of the present invention to provide a technique that can perform deformation detection substantially in real time.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a deformation measurement system according to the present invention is attached to a first part of a deformation measurement object, outputs a plurality of measurement light beams, and a second part of the deformation measurement object. Means for detecting the two-dimensional light receiving position of each measurement light beam, and the relative relationship between the first part and the second part based on the two-dimensional light receiving position of each measurement light beam. Means for calculating deformation.
[0010]
In addition, the system according to the reference example is attached to the first part of the deformation measurement object, and outputs a plurality of measurement light beams and receives the reflected light of each measurement light beam. A displacement meter for measuring the distance to the reflection position of the reflected light; a reflecting means attached to the second part of the deformation measurement object; and reflecting each measurement light beam to the displacement meter; and each measurement light beam Means for calculating relative deformation between the first part and the second part based on the distance to each reflection position.
[0011]
The system according to the present invention is a displacement measurement device that is attached so as to be relatively fixed with respect to the first part of the deformation measurement object, and outputs a plurality of measurement light beams and reflects each of them. A displacement measuring device that receives light and measures the distance to the reflection position of the reflected light for each of the measurement light beams, and is attached so as to be relatively fixed with respect to the second part of the deformation measurement object. A light receiving position detecting device for detecting each two-dimensional light receiving position by receiving each measuring light beam from the displacement measuring device, and reflecting each measuring light beam to the displacement measuring device; a reflecting means for the light receiving position detecting apparatus wherein the displacement the distance to the reflection position of each measurement light beam obtained by the measuring device, wherein each measuring light beam obtained by the light receiving position detecting device Comprising a receiving position of dimensions, a deformation calculation unit for calculating the relative deformation between the second portion and the first portion based on.
[0012]
In a preferred aspect of this configuration, the reflecting means is provided on the front surface side of the position detecting means, reflects a part of each of the incident measuring light beams to the displacement measuring device, and another part. Is a beam splitter that guides to the position detecting means.
[0013]
Further, in the method according to the present invention, a displacement measuring device that outputs a plurality of measurement light beams, receives each reflected light, and measures the distance to the reflection position of the reflected light for each measurement light beam. A position detection unit that is attached to be relatively fixed with respect to the first part of the deformation measurement object, receives each measurement light beam from the displacement measurement device, and detects each two-dimensional light receiving position; A light receiving position detecting device including a reflecting means for reflecting each measurement light beam to the displacement measuring device so as to be fixed relative to the second part of the deformation measuring object, The first part based on the distance to the reflection position for each measurement beam obtained by the displacement measuring device and the two-dimensional light receiving position of each measurement light beam obtained by the light receiving position detecting device. And the second part Calculating the relative deformation between.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.
[0015]
FIG. 1 is a diagram showing a schematic configuration of a deformation measurement system according to the present invention. As shown in the figure, this system uses two laser displacement meters 10 and a PSD unit 20. This system is for obtaining a relative deformation between two parts of an object such as a vehicle. When performing deformation measurement, the pair of laser displacement meters 10 is attached so as to be fixed relative to one part, and the PSD unit 20 is fixed relative to the other part. Attached to.
[0016]
The structure of the PSD unit 20 is shown in FIG. 2A is a perspective view, and FIG. 2B is a view of the unit 20 viewed from the front (that is, in the direction of arrow A in FIG. 2A). As shown in this figure, the PSD unit 20 includes two two-dimensional PSDs (Position Sensitive Detectors) 24. The two PSDs 24 are arranged in a line at a predetermined interval. As is well known, PSD outputs an analog signal proportional to the position of the incident spot of the light beam. In the case of a rectangular two-dimensional PSD, a signal indicating the x coordinate and a signal indicating the y coordinate of the light incident spot in the rectangular plane of the PSD are output. A beam splitter 22 is provided on the front side of each PSD 24 (that is, on the laser beam incident direction side). The beam splitter 22 reflects a part of the laser beam incident from the laser displacement meter 10 toward the PSD 24 and returns it to the laser displacement meter 10, while allowing another portion to pass straight and enter the PSD 24. The size of the PSD 24 is preferably set so that the spot does not come out of the PSD 24 even if the position of the incident spot relatively moves due to deformation of the measurement object.
[0017]
Here, PSD is used as a device for detecting the light receiving position of the laser beam, but this is merely an example. The system of the present embodiment can also be realized by using other devices and apparatuses that can output signals corresponding to coordinate values in the two axial directions of the light receiving position instead of PSD.
[0018]
The two laser displacement meters 10 used in this system correspond to the two PSDs 24 of the PSD unit 20, respectively. When these two laser displacement meters 10 are attached to an object for deformation measurement, the arrangement of the laser displacement meters 10 is determined so that the output beam of each laser displacement meter 10 enters the corresponding PSD 24. Of course, it is also preferable to fix the two laser displacement meters 10 to one unit. In this case, both displacement gauges 10 are set so that the distance between the two laser displacement meters 10 (or more precisely, the distance between the parallel laser beams output by the displacement gauges 10) is equal to the distance between the two PSDs 24 in the PSD unit 20. The arrangement configuration may be determined.
[0019]
The laser displacement meter receives the reflected light of the laser beam output as well known, and outputs a signal indicating the distance from the displacement meter to the reflection point. Here, as the laser displacement meter, a type that detects reflected light with a position detecting element such as PSD and obtains a distance from the detected signal to the reflection position by the principle of trigonometry is used. Of course, this is just an example, and even if it is not such a type of laser displacement meter, use it if it can determine the distance to the reflection point of the laser beam based on the output laser beam. Can do. However, it is necessary to have a measurement range in which the amount of deformation of the assumed object can be measured. The output signal of each laser displacement meter 10 (signal indicating the distance to the laser reflection position) is also input to the data recorder 30.
[0020]
The PSD unit controller 25 controls the PSD unit 20 and supplies the output signals (signals indicating the x and y coordinates of the incident light spot) of each PSD 24 therein to the data recorder 30.
[0021]
The data recorder 30 records each detection signal input from the laser displacement meter 10 and the PSD unit controller 25 on a predetermined recording medium or outputs it to various communication means such as a LAN or a wireless LAN. It is also preferable to provide a display device or a print output device in the data recorder 30 and display or output each detection signal in real time.
[0022]
The computer for numerical analysis 40 receives information on these detection signals from the data recorder 30 via a recording medium or communication means, and calculates a relative deformation between two parts to be measured from these detection signals. Details of this calculation will be described later.
[0023]
FIG. 3 is a diagram showing an installation configuration example of this system. This example is one example of attachment to an automobile body. In this example, a pair of laser displacement meters 10 is attached to the front side member 100 of the body, and a PSD unit 20 is attached to a suspension tower 110 to which a spring support at the upper part of the front wheel suspension is attached. The relative deformation with 110 is measured. The front side member 100 is a portion that is relatively difficult to deform. In this example, the deformation of the suspension tower 110 with respect to this portion is measured.
[0024]
Here, since it is often difficult to attach the laser displacement meter 10 or the PSD unit 20 as it is to each part of the vehicle, here, the attachment according to the attachment target part (in this example, the suspension tower 110 and the front side member 100). Jigs 50 and 52 are prepared and attached using them. In the case of the laser displacement meter 10, the mounting jig 50 is fixed to the front side member 100 using a hole existing in the front side member 100, and the pair of laser displacement meters 10 is fixed to the jig 50. is doing. The PSD unit 20 needs to be attached to the pair of the laser displacement meters 10 installed in this way so that the front surface (installation surface of the beam splitter 22) faces the beam output surface of the laser displacement meter 10. Therefore, in this example, the mounting jig 52 is provided so as to project from the suspension tower 110 onto the laser displacement meter 10 installation portion, and the PSD unit 20 is attached to the lower surface of the mounting jig 52, whereby the above arrangement configuration is achieved. Realized. The attachment jig 52 is attached and fixed to the suspension tower 110 using a suspension attachment nut or the like provided in the suspension tower 110.
[0025]
In this way, each laser displacement meter 10 and each PSD 24 of the PSD unit 20 corresponding to each laser displacement meter 10 are attached in a state of sharing the optical system. That is, a part of the laser emitted from the laser displacement meter 10 is reflected by the corresponding beam splitter 22 and returns to the laser displacement meter 10, and the other part is transmitted through the beam splitter 22 and incident on the PSD 24. It becomes like this. Thereby, the laser displacement meter 10 and the corresponding PSD 24 are in a state where each measurement can be performed using the same laser beam.
[0026]
Here, the mounting jigs 50 and 52 have sufficiently high rigidity so that the deformation and vibration of the mounting jigs 50 and 52 themselves can be substantially ignored. As a result, the pair of laser displacement meters 10 and the PSD unit 20 are attached in a form that is relatively fixed with respect to the respective measurement target parts.
[0027]
The example of mounting the pair of laser displacement meters 10 and the PSD unit 20 has been described above. In addition, the PSD unit controller 25 and the data recorder 30 are also installed in an empty space of the same vehicle. The numerical analysis computer 40 can be mounted on the vehicle, or a computer placed in another place can be used as the numerical analysis computer 40. In the former case, the measurement data may be supplied from the data recorder 30 to the numerical analysis computer 40 via a LAN or the like. In the latter case, the measurement data can be supplied to the numerical analysis computer 40 by temporarily recording it on a portable recording medium or using wireless communication.
[0028]
Next, the calculation principle of relative deformation by the system of this embodiment will be described with reference to FIGS.
[0029]
First, the deformation calculated from the detection signal of the PSD unit 20 will be described with reference to FIG. Here, in order to make the explanation easy to understand, orthogonal coordinate systems L, W, and H are taken as shown in the figure. The L axis is an axis in the length direction of an object (for example, a vehicle), the W axis is an axis in the width direction, and the H axis is an axis in the height direction. The coordinate system shown here corresponds to the case where the laser displacement meter 10 and the PSD unit 20 are attached as shown in FIG. 3, and the direction in which the H axis connects the laser beam source of the displacement meter 10 and the corresponding PSD 24. Is consistent with
[0030]
Here, in order to simplify the description, a case where the position / posture of the PSD unit 20 in the WL plane changes as shown in FIG. 4A with respect to the time t1 is taken as an example. The position / posture of the PSD unit 20 shown in FIG. 4 is a relative position / posture based on the laser displacement meter 10. When the position / posture of the PSD unit 20 in the WL plane changes in this way, the position of the beam receiving spot of each PSD 24 (hereinafter referred to as PSD1, PSD2) in the PSD changes. That is, although the position of the spot when viewed from the laser displacement meter 10 does not change, the position of the light receiving spot in the individual PSDs 1 and 2 changes according to the relative movement of the PSD unit, and accordingly the Ls of the PSDs 1 and 2 change accordingly. The signal and the W signal change.
[0031]
FIG. 4B shows the change. The vertical axis represents displacement (mm) and the horizontal axis represents time (seconds). In this example, the state before the time t1 is calibrated with the displacement 0, and the displacement amount appears in the L and W outputs of the PSDs 1 and 2 after the time t1.
[0032]
Here, a state before t1 is set as a reference state (a state in which no deformation occurs), and a deformation after t1 with respect to this reference state is calculated. From the detection result of the PSD unit 20, a total of three-axis deformation (displacement) including a relative displacement in the L direction between the 10 pairs of the laser displacement meter and the PSD unit 20, a displacement in the W direction, and a twist (rotation) around the H axis. ) Can be calculated.
[0033]
First, the displacement in the L direction and the displacement in the W direction at a certain time can be obtained from the average of the L output signals and the average of the W output signals of PSDs 1 and 2, for example, at that time. However, it is assumed that the L and W signals in the reference state are calibrated so as to indicate zero displacement. The calibration may be performed, for example, by accurately positioning and mounting the pair of displacement meters 10 and the PSD unit 20 so that the laser beam from the displacement meter 10 is incident on the exact center of the corresponding PSD 24. Alternatively, for example, the PSD unit controller 25 adjusts the output of the PSD 24 so that the position where the laser beam is incident on the PSD 24 in the reference state indicates L = 0, W = 0, or the data recorder at the subsequent stage. 30 or the numerical analysis computer 40 can store the incident spot position (L, W) in the reference state as a reference value and subtract the reference value from the measured value to obtain the correct displacement.
[0034]
On the other hand, the twist angle Δθ1 around the H axis can be calculated from the following relational expression [Relational expression 1].
Δθ1 = tan ⁻¹ {(L1-L2) / (distance between PSD1 and 2)}
Here, L1 is the L displacement of the light receiving spot of PSD1, and L2 is the L displacement of the light receiving spot of PSD2. The interval between PSD1 and PSD2 is the interval between the center point of PSD1, PSD2, and the center point. However, here, it is assumed that PSD1 and PSD2 are aligned along the W direction in the reference state.
[0035]
Next, the relative deformation calculated from the pair of laser displacement meters 10 will be described with reference to FIG. The coordinate system shown in this figure is the same as that in FIG.
[0036]
As shown in FIG. 5, each laser displacement meter 10 receives the laser beam reflected by the beam splitter 22 at the opposite position, and based on this, the beam reflection position (that is, the corresponding beam splitter) is received from each displacement meter 10. The distances H1 and H2 to 22) are obtained. By taking, for example, an average of these distances H1 and H2, the relative displacement in the H direction between the laser displacement meter 10 pair and the PSD unit 20 is obtained (however, the calibration is performed so that the H direction distance is 0 in the reference state). ).
[0037]
Furthermore, the torsion angle Δθ2 about the L axis can be obtained from the following relational expression.
[0038]
[Relational expression 2]
Δθ2 = tan ⁻¹ {(H1−H2) / (distance between PSD1 and 2)}
In this way, the relative deformation about the total two axes of the displacement in the H direction and the twist angle around the L axis can be obtained by the pair of laser displacement meters 10.
[0039]
As explained above, by installing and measuring the pair of laser displacement meters 10 and the PSD unit 20 so as to share the optical system as described above, the displacements in the L, W, and H directions and the H axis rotations are measured. Relative deformation information about a total of five axes, that is, twist angles Δθ1 and Δθ2 around the L axis can be obtained.
[0040]
In the present embodiment, the laser displacement meter 10 and the PSD unit 20 are attached not directly to two parts where relative deformation is to be measured, but via attachment jigs 50 and 52. The above-described measurement principle is to obtain the relative deformation (displacement) between the laser displacement meter 10 and the PSD unit 20, but those skilled in the art can use the attachment jigs 50 and 52 that are not easily deformed. Obviously, the relative deformation between the two sites of interest can be obtained by performing simple transformation (enlargement, reduction, etc.) on the relative deformation obtained by the principle.
[0041]
FIG. 6 is a diagram showing a time change state of the deformed state obtained in an experiment performed by attaching the system of the present embodiment to the vehicle as shown in FIG. In this example, the vehicle travels in a slalom along a sinusoidal curve, and only the time waveforms of three displacement amounts in the W, H, and L directions are shown to avoid complication. From this figure, it can be seen that, for example, the amount of displacement in each direction changes according to the slalom running, and the magnitude of the displacement varies depending on the direction.
[0042]
According to the system exemplified above, the displacement meter 10 and the corresponding PSD 24 share the optical system of the two laser displacement meters 10 and the PSD unit 20 including the two PSDs 24 (that is, measurement can be performed with the same laser beam). By installing and measuring in this way, the deformation amount about the five axes can be measured with a relatively compact configuration. Further, according to this system, even when the entire object (for example, a vehicle) is moving, only the relative deformation component between the laser displacement meter 10 pair and the PSD unit 20 is detected. Therefore, for example, this system can be applied to an actual driving test of an automobile. Further, according to this system, the output signal of each laser displacement meter 10 and the output signal of each PSD 24 can be displayed on the data recorder 30 in real time. Each of these output signals itself can be said to indicate a kind of deformation information, and if this is displayed in real time, the analyst can know the state of deformation in real time. Moreover, since the calculation itself for obtaining the above-described total five-axis deformation information from the output signals from these sensors is also a very simple calculation, the five-axis deformation information itself can be calculated substantially in real time. Thus, according to this embodiment, the state of deformation every moment can be obtained in real time.
[0043]
The preferred embodiment of the present invention has been described above, but this is only an example, and various modifications can be made within the scope of the technical idea of the present invention. For example, it is also possible to prepare a plurality of sets of the above-mentioned 10 pairs of laser displacement meters and the PSD unit 20 and simultaneously measure a plurality of sets of relative deformation between a pair of parts. In this case, the data recorder 30 and the numerical analysis computer 40 in the system configuration shown in FIG. 1 can be shared by a plurality of sets.
[0044]
For example, in the case of an automobile, in addition to the installation site shown in FIG. 3, for example, as shown in FIG. 7, the PSD unit 20 is attached to the front end of the front side member 100 via an attachment jig (not shown). The deformation of the front side member can be measured by attaching a pair of the laser displacement gauges 10 so as to share the optical system with the unit 20 via a mounting jig below the cross member. In addition, in the case of automobiles, relative deformation between them can be measured by attaching 10 pairs of laser displacement meters on one side and the PSD unit 20 on the other side to the left and right front side members. Further, the relative deformation of each part similar to that on the front side can be obtained on the rear side.
[0045]
Further, in the above example, by using one pair of laser displacement meters 10 and one pair of PSD 24, a total of five axes (each displacement in the L, W, and H directions, and each twist angle around the H axis and each L axis). Although the simultaneous measurement was performed, the torsion angle around the W axis can be measured by further increasing the laser displacement meter 10 and the PSD 24 one by one. In this case, the three PSDs 24 need not be aligned. For example, as shown in FIG. 8, a PSD unit 60 in which three PSDs 24 (and a beam splitter 22 provided in front of them) are arranged in an equilateral triangle can be considered. Of course, the three laser displacement meters 10 corresponding to this need to be attached to the target site in such an arrangement that the optical system can be shared with the corresponding PSD 24. By using three pairs of PSD-laser displacement meters in this way, it is possible to measure relative deformation about a total of six axes.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a schematic configuration of a system according to an embodiment.
FIG. 2 is a diagram for explaining a configuration of a PSD unit.
FIG. 3 is a diagram illustrating a mounting configuration example of the system according to the embodiment.
FIG. 4 is a diagram for explaining a calculation principle of relative deformation by the system of the embodiment.
FIG. 5 is a diagram for explaining a calculation principle of relative deformation by the system of the embodiment.
FIG. 6 is a diagram illustrating an example of a temporal change in deformation (displacement amount) in each axial direction obtained by an experiment using the system of the embodiment.
FIG. 7 is a view showing another example of the mounting configuration of the system according to the embodiment.
FIG. 8 is a diagram illustrating a configuration example of a PSD unit for six-axis measurement as a modification of the embodiment.
[Explanation of symbols]
10 laser displacement meter, 20 PSD unit, 22 beam splitter, 24 PSD, 25 PSD unit controller, 30 data recorder, 40 computer for numerical analysis.

Claims (4)

Means for outputting a plurality of measurement light beams attached to the first part of the deformation measurement object;
Means for detecting the two-dimensional light receiving position of each measurement light beam attached to the second part of the deformation measurement object;
Means for calculating a relative deformation of the first part and the second part based on a two-dimensional light receiving position of each measurement light beam;
A deformation measurement system comprising: A displacement measuring device attached so as to be relatively fixed with respect to a first part of a deformation measuring object, which outputs a plurality of measurement light beams and receives reflected light from each of the measurement light beams. A displacement measuring device that measures the distance to the reflection position of the reflected light for each beam;
A light receiving position detecting device attached so as to be relatively fixed with respect to the second part of the deformation measurement object, wherein each two-dimensional light receiving position is received by receiving each measurement light beam from the displacement measuring device. A light receiving position detecting device comprising: a position detecting means for detecting the light; and a reflecting means for reflecting each of the measurement light beams to the displacement measuring device;
Based on the distance to the reflection position for each measurement light beam obtained by the displacement measurement device and the two-dimensional light reception position of each measurement light beam obtained by the light reception position detection device, A deformation calculation device for calculating a relative deformation between a part and the second part;
A deformation measurement system comprising: The reflecting means is provided on the front side of the position detecting means, reflects a part of each of the incident measurement light beams to the displacement measuring device, and guides another part to the position detecting means. The deformation measurement system according to claim 2 , wherein the deformation measurement system is a beam splitter. A displacement measurement device that outputs a plurality of measurement light beams, receives each reflected light, and measures the distance to the reflection position of the reflected light for each of the measurement light beams. Attach to be fixed relative to the part,
Position detecting means for receiving each measurement light beam from the displacement measuring device and detecting each two-dimensional light receiving position, and reflecting means for reflecting the measurement light beam to the displacement measuring device. The light receiving position detection device is attached so as to be relatively fixed with respect to the second part of the deformation measurement object,
The first part based on the distance to the reflection position for each measurement beam obtained by the displacement measuring device and the two-dimensional light receiving position of each measurement light beam obtained by the light receiving position detecting device. And calculating the relative deformation between the second part and
Deformation measurement method.

Images