JP3546599B2 - Two-dimensional displacement sensor and two-dimensional displacement measuring device using the same - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a two-dimensional displacement sensor capable of automatically measuring a two-dimensional displacement such as a surface difference or a gap between two objects, and a two-dimensional displacement measuring device using the same.
[0002]
[Prior art]
Automotive exterior resin parts such as bumpers may undergo thermal deformation depending on the usage environment such as extremely high temperature or extremely low temperature. Therefore, quality evaluation is performed by a heat and cold resistance test in a development stage or the like. This kind of heat and cold resistance test is to put the actual vehicle with the exterior resin parts installed in a constant temperature room of, for example, -40 ° C to 90 ° C, and measure the surface difference and the change in the gap size from the vehicle body at extremely constant temperature and extremely low temperature. It is one item of quality evaluation of exterior resin parts.
[0003]
[Problems to be solved by the invention]
However, the surface difference or gap in the conventional heat-resistant cold test, since measurer was measured directly using a gauge, measuring person in a thermostatic chamber of before and after cryogenic and 90 ° C. pole high temperature before and after -40 ℃ is I had to enter the room. Since it is extremely difficult to stay in such a constant temperature chamber for a long time, the time required for measurement must be as short as possible. There was a restriction on raising In addition, this type of heat and cold resistance test is performed for a long time in an extremely constant temperature or extremely low temperature environment, and it is necessary to measure the change over time. It was difficult to obtain change data.
[0004]
The present invention has been made in view of such problems of the related art, and has as its object to provide a two-dimensional displacement sensor that can automatically measure two-dimensional displacement.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a two-dimensional displacement sensor according to the present invention described in claim 1 is a two-dimensional displacement sensor that detects a two-dimensional displacement in an arbitrary cross section of two objects. A first post having a first measurement reference portion fixed to the measurement surface of the one object, and a second measurement fixed to the measurement surface of the other object of the two-dimensional displacement to be measured; A second post having a reference portion, a first link pivotally mounted on the first post such that one end is relatively rotatable about a vertical axis of the arbitrary cross section, and one end The second post is pivotally mounted so as to be relatively rotatable about the vertical axis of the arbitrary cross section, and the other end is relatively rotatable about the vertical axis of the arbitrary cross section. A second link pivotally mounted on the first link and the first post At least two of a rotation axis between the first link, a rotation axis between the second post and the second link, and a rotation axis between the first link and the second link. A first angle detection unit and a second angle detection unit that respectively detect a rotation angle of the rotation shaft ;
The rotation axis of the first post and the first link, and the rotation axis of the second post and the second link, respectively, along each direction of the two-dimensional displacement to be measured It is characterized by being provided at a distance .
[0006]
In the two-dimensional displacement sensor according to the present invention, the first measurement reference portion of the first post is provided on the measurement surface of one object, and the second measurement reference portion of the second post is provided on the measurement surface of the other object. fixed to the measurement surface, this time, (hereinafter also referred to as P ₁₎ rotation axis of the first post and the first link, the rotary shaft of the second post and a second link (hereinafter P ₂ both say), and the first link and by utilizing the geometric properties of the triangle formed by three points of pivot axis between the second link (hereinafter referred to as P _3), any cross-section of two objects The two-dimensional displacement at is detected.
[0007]
In other words, the two-dimensional displacement of the two objects to be measured in an arbitrary cross section can be replaced by the coordinates of the _two rotation axes P ₁ and P _{2 on} the XY plane of the arbitrary cross section. Further, the lengths of the first link and the second link, that is, the lengths of the two sides of the triangle are already known, and two interior angles of the triangle are obtained by the first angle detecting means and the second angle detecting means. Therefore, the point coordinates of the _two rotation axes P ₁ and P ₂ can be obtained by geometric calculation. Therefore, by using the two-dimensional displacement sensor of the present invention, the two-dimensional displacement to be measured can be automatically measured.
[0008]
In the two-dimensional displacement sensor according to claim 1, whatever the triangle triangle formed by the three pivot axes P _1, P _2, P _3, to obtain the two-dimensional displacement by geometric calculation The two-dimensional displacement sensor according to claim 2, wherein the rotation axis of the first post and the first link, and the rotation axis of the second post and the second link, It is provided on a non-collinear line with respect to the two-dimensional displacement direction to be measured.
[0009]
Depending on the two-dimensional displacement to be measured, the two-dimensional displacement may not be greatly reflected in the change in the internal angle of the triangle due to the geometrical properties of the triangle. That is, the shape of the triangle formed by the three pivot axes P _1, P _2, P ₃ is sometimes sensitivity of the two-dimensional displacement sensor becomes dull, a two-dimensional displacement sensor of claim 1, wherein the Since the configuration is made so as to avoid the range where the sensitivity becomes dull, the measurement accuracy is remarkably improved.
[0010]
In order to achieve the above object, the two-dimensional displacement measuring device according to claim 2, the two-dimensional displacement sensor according to claim 1, wherein the first angle detecting means and the second angle of the two-dimensional displacement sensor Calculating means for calculating the two-dimensional displacement to be measured based on an output signal from the detecting means.
[0011]
In the two-dimensional displacement measuring apparatus of the second aspect, it comprises a two-dimensional displacement sensor according to claim 1, wherein the above, and since also comprises a calculating means for arithmetically processing the output signal from the two-dimensional displacement sensor, Measurement of two-dimensional displacement can be performed automatically.
[0012]
【The invention's effect】
According to the two-dimensional displacement sensor of the first aspect, the two-dimensional displacement can be easily obtained by calculation using the geometrical properties of the triangle, so that there is no error by the operator and the measurement accuracy is improved. Further, since the calculation can be performed based on the outputs from the first angle detecting means and the second angle detecting means, the two-dimensional displacement can be easily measured even in an environment where the measurer is difficult to approach.
[0013]
According to the two-dimensional displacement sensor of the second aspect, in addition to the effect of the two-dimensional displacement sensor of the first aspect, the measurement sensitivity is increased and the measurement accuracy is improved.
[0014]
According to the two-dimensional displacement measuring device of the third aspect, since the geometric calculation is also automatically performed on the output from the two-dimensional displacement sensor, it is possible to increase the number of measurement sites or set the measurement interval short. This makes it possible to further improve the measurement accuracy.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing an embodiment of the two-dimensional displacement sensor of the present invention, FIG. 2 is a perspective view showing the same use state, and FIGS. 3 and 4 are front views for explaining the measurement principle of the two-dimensional displacement sensor. It is.
[0016]
As shown in FIG. 1, the two-dimensional displacement sensor 100 according to the present embodiment includes a first post 10 and a second post 20, and a first link 30 and a second link 40 connecting the first and second posts 20 and 20. .
[0017]
The first post 10 is a member fixed to one of the objects to be measured, and the second post 20 is a member fixed to the other of the objects to be measured. For example, as shown in FIG. 4, when measuring the surface difference M and the gap S between the vehicle body V and the bumper B, the first post 10 is connected to the bottom surface 12 which is a measurement reference portion of the first post 10. Is brought into contact with, for example, the flat portion V1 of the vehicle body V, and the side surface 14 as another measurement reference portion is aligned and fixed to the vertical portion V2 of the vehicle body V. Further, as shown in the figure, the second post 20 has a bottom surface 22 which is a measurement reference portion of the second post 20 abutted on, for example, the flat portion B1 of the bumper B, and has another measurement reference portion. A certain side surface 24 is aligned and fixed to the vertical portion B2 of the bumper B.
[0018]
As described above, the first post 10 and the second post 20 can be directly or indirectly contacted with the measured surfaces V1, V2, B1, and B2 of the gap M and the gap S to be measured. In the present embodiment, each of the bottom surfaces 12 and 22 is a measurement reference portion that directly abuts against the surface to be measured V1, B1, and has a side surface. Reference numerals 14 and 24 are measurement reference portions that are indirectly abutted on the surfaces to be measured V2 and B2.
[0019]
The first post 10, one end of the first link 30 is pivotally connected about a pivot axis P _1. The second post 20, one end of the second link 40 is pivotally connected about a pivot axis P _2. The other end and the other end of the second link 40 of the first link 30 is also at equal distance from one end of each of R (see FIG. 4), it is pivotally connected about a pivot axis P ₃ I have. These three rotation axes P ₁ , P ₂ , P ₃ are all provided in parallel, so that the first post 10, the second post 20, the first link 30, and the second link 40 The four members move parallel to a plane PL perpendicular to the rotation axes P ₁ , P ₂ , and P ₃ , and the plane PL becomes an arbitrary cross section to be measured, and is an X direction in the plane PL. And the displacement in the Y direction are obtained.
[0020]
In addition, the two-dimensional displacement sensor 100 according to the present embodiment, as shown in FIG. 3, has the first post 10 and the second post 20 when the respective measurement reference surfaces 12, 14, 22, 24 are aligned with each other. turning shaft P ₁ and P ₂ are measured displacement direction, that is, formed so as not located on a straight line along an X-Y direction shown in FIG. This is to further increase the measurement sensitivity, and its principle will be described later.
[0021]
A potentiometer 50, which is first angle measuring means, is provided on a pivot axis P2 between the second post 20 and the second link 40 to measure a pivot angle ω about the pivot axis. cage, the first link 30 to pivot axis P ₃ of the second link 40, the potentiometer 60 is provided a second angle measuring means for measuring the rotation angle ψ of the rotating shaft around Have been. These potentiometers 50 and 60 output rotation angles ω and ψ as voltage differences, and output signals of the potentiometers 50 and 60 are input to a personal computer 80 via a data collector 70 as shown in FIG. .
[0022]
In the present embodiment, is provided with the potentiometers 50 a first angle detecting means to the rotation axis P ₂ of the second post 20 and the second link 40, provided on the pivot shaft P ₂ instead to be provided with first posts 10 to pivot axis P ₁ of the first link 30. Also, the potentiometer 60 is a second angle detecting means is not limited only to the pivot axis P ₃ of the first link 30 and second link 40, in short, the three pivot axes P _1, P _2, potentiometers 50 and 60 in at least two pivot axes of the P ₃ may as long provided.
[0023]
Next, the measurement principle and usage will be described.
As shown in FIG. 4, consider the case of measuring the surface difference M ₁ and the gap S ₁ between the vehicle body V and the bumper B. Assuming a right triangle P ₁ P ₂ A having a straight line connecting the rotation axes P ₁ and P ₂ as the hypotenuse, the length of the hypotenuse is L, the angle P ₁ P ₂ A is θ, and the length of P ₁ A is M , P ₂ A is S,
(Equation 1)
M = Lsin θ (1)
S = Lcos θ (2)
It becomes.
[0024]
The length M is a value obtained by adding a surface difference M ₁ to be obtained to the length M ₀ in the basic state shown in FIG. 3, the length S is to be determined on the length S ₀ in the basic state shown in FIG. 3 is a value obtained by adding the gap S _1. Therefore, if M and S are obtained from the above equations (1) and (2), M ₀ and S ₀ are known, and the target surface difference M ₁ and gap S ₁ are obtained.
(Equation 2)
M ₁ = M−M ₀ … (3)
S ₁ = S−S ₀ (4)
[0025]
As shown in FIG. 4, the first angle detecting means rotation angle of the rotation shaft P ₂ around the potentiometer 50 omega is is detected, pivot shaft P ₃ around the potentiometer 60 is a second angle detecting means Is detected. Further, since the distance R is equal between the pivot axis _P 1, the distance between _{P 3} R and the pivot axis _{P 2, P 3, △ P} 1 P 2 P 3 is always an isosceles triangle. Therefore, the distance L between the rotation axes P ₁ and P ₂ can be obtained by the following equation (5) using the vertex angle の and the length R of the isosceles triangle. When the angle θ is represented by ω and ψ, the following equation (6) is obtained from the geometric relationship.
[Equation 3]
L = 2Rsin (ψ / 2) (5)
θ = ω− (π−ψ) / 2 (6)
[0026]
By substituting the known length R and the values measured by the potentiometers 50 and 60 into these equations (5) and (6), L and θ are obtained, and these L and θ are calculated by equations (1) and (2). By substituting into the equation, M and S are obtained. Then, the surface difference M ₁ of interest by substituting these M and S (3) and (4), is determined and the clearance S _1.
[0027]
The above is the measurement principle of the two-dimensional displacement sensor 100 of the present embodiment. The two-dimensional displacement sensor 100 is preferably used when measuring a change with time such as thermal deformation. For example, when measuring the distortion of the bumper due to extremely low temperature or extremely high temperature, a plurality of two-dimensional displacement sensors 100 of the present embodiment are mounted between the vehicle body V and the bumper B, as shown in FIG. Output signals from the potentiometers 50 and 60 of the sensor 100 are collected by a data collector 70. The data collected by the data collector 70 is input to a personal computer 80 connected thereto, and the above-described calculation is executed instantaneously. This eliminates the need for the measurer to enter a constant temperature room with a poor working environment, increases the number of measurement sites, or can measure long-term changes over time in extremely constant temperature or extremely low temperature environments, Highly accurate data can be obtained.
[0028]
Next, the sensitivity of the two-dimensional displacement sensor 100 of the present embodiment will be described.
From the above equations (1) to (6), the angle ω measured by the potentiometer 50 and the angle ψ measured by the potentiometer 60 are calculated using the surface difference M, the gap S, and the link length R as follows. Is represented as
(Equation 4)
{= ² sin ^-1 {(M ² + S ² ) ^1/2 / 2R}
2tan ^-1 {(M ² + S ² ) / (4R ² −M ² −S ² )} ^1/2 (7)
ω = tan ⁻¹ (M / S) + (π−ψ) / 2
= Tan ^-1 (M / S) + π / 2-sin ^-1 {(M ² + S ² ) ^1/2 / 2R}
… (8)
[0029]
The degree of change of the angle ψ due to the surface difference M, that is, the sensitivity, is obtained by partially differentiating ψ with M.
(Equation 5)
δψ / δM
= [{1- (M ² + S ² ) / 4R ² } (M ² + S ² ) / 4R ² }] ^1/2 · M / 2R ²
… (9)
[0030]
Similarly, the sensitivity of the angle に よ る due to the gap S is obtained by partially differentiating ψ with S.
(Equation 6)
δψ / δS
= [{1- (M ² + S ² ) / 4R ² } (M ² + S ² ) / 4R ² }] ^1/2 · S / 2R ²
… (10)
[0031]
In the above equations (9) and (10), when the values of δψ / δM and δψ / δS are close to 0, the change in the angle ψ is small even if the surface difference M and the gap S are large, that is, the sensitivity is low. It is considered that both sides of the expression (9) become 0 when 1− (M ² + S ² ) / 4R ² = 0 or M = 0 or S = 0.
[0032]
When 1− (M ² + S ² ) / 4R ² = 0, that is, when M ² + S ² = (2R) ² , it represents on the circumference of radius 2R centering on the point of M = S = 0. However, since the radius is 2R, the first and second links 30 and 40 are fully extended, and the condition is that ψ = π, which is a state that cannot be used due to design during actual use. Therefore, a region where the sensitivity is low can be avoided.
[0033]
When M = 0, the sensitivity of the angle ψ is weak. However, in the two-dimensional displacement sensor 100 of the present embodiment, the value of M0 is given in advance, avoiding the region where M = 0 as described above. Measurement is not performed in the region with the lowest sensitivity. That is, as long as the second post 20 is attached to an object having a lower surface difference with respect to the first post 10, M = 0 does not occur, so that the sensitivity does not decrease.
[0034]
Further, the sensitivity of the angle ψ also becomes weak when S = 0, but as shown in FIG. 3, as long as the first post 10 and the second post 20 have a thickness, S = 0 actually. There is no case, and therefore, the sensitivity does not decrease.
[0035]
As described above, in the two-dimensional displacement sensor 100 of the present embodiment, since the sensitivity of the potentiometers 50 and 60 is also taken into account, the responsiveness to the surface difference M and the gap S is good, and the measurement accuracy is significantly improved. .
[0036]
The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a two-dimensional displacement sensor of the present invention.
FIG. 2 is a perspective view showing a use state of the two-dimensional displacement sensor and the two-dimensional displacement measuring device of the present invention.
FIG. 3 is a front view showing the two-dimensional displacement sensor of FIG. 1;
FIG. 4 is a front view for explaining a measurement principle of the two-dimensional displacement sensor of FIG. 1;
[Explanation of symbols]
10 First Post 12 Measurement Reference Unit 14 Measurement Reference Unit 20 Second Post 22 Measurement Reference Unit 23 Measurement Reference Unit 30 First Link 40 Second Link 50 Potentiometer (First Angle detection means)
60 Potentiometer (second angle detecting means)
P ₁ , P ₂ , P ₃ ... rotating axis PL ... cross section

Claims (2)

A two-dimensional displacement sensor that detects a two-dimensional displacement in an arbitrary cross section of two objects,
A first post having a first measurement reference portion fixed to a measurement surface of the one object of the two-dimensional displacement to be measured;
A second post having a second measurement reference portion fixed to the measured surface of the other object of the two-dimensional displacement to be measured;
A first link pivotally mounted on the first post such that one end is relatively rotatable about a vertical axis of the arbitrary cross section;
One end is pivotally mounted on the second post such that it is relatively rotatable about the vertical axis of the arbitrary cross section, and the other end is rotatable relatively about the vertical axis of the arbitrary cross section. A second link pivotally attached to the first link so that
A rotation axis between the first post and the first link, a rotation axis between the second post and the second link, and a rotation between the first link and the second link. First angle detection means and second angle detection means for respectively detecting the rotation angles of at least two of the rotation axes ,
The rotation axis of the first post and the first link, and the rotation axis of the second post and the second link, respectively, along each direction of the two-dimensional displacement to be measured A two-dimensional displacement sensor which is provided at a distance. A two-dimensional displacement sensor according to claim 1 ,
Calculating means for calculating the two-dimensional displacement to be measured based on output signals from the first angle detecting means and the second angle detecting means of the two-dimensional displacement sensor. Dimensional displacement measuring device.

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