JP2004361372A - Angle measurement device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-accuracy angle measurement device not affected by expansion or contraction of an electrolytic solution caused by a change of surrounding temperature, not affected by instability of a contact surface by surface tension of the electrolytic solution, or not affected aging effect or the like of the electrolytic solution. <P>SOLUTION: This angle measurement device has: a closed chamber wherein two faces opposite to each other have wall faces made of light-transmissive members; a liquid sealed in the chamber such that the liquid has a bubble; a light emission source provided on one wall face side of the light-transmissive wall faces; and a CCD element provided close to the other wall face side of the light-transmissive wall faces. Positions of both the side ends of the bubble are detected from image information of the CCD element to find a center position of the bubble, and an angle is detected from a displacement amount of the bubble to a reference position. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus that is attached to a building member such as a column or a beam, for example, and that measures the inclination angle of these building members, or that is attached to a main body or the like of a surveying instrument to measure the inclination angle of the main body or the like. The present invention relates to an electronic angle measuring device capable of measuring a minute angle change with high accuracy.
[0002]
[Prior art]
In recent years, instead of a conventional visual angle measuring device as a measuring device or a detector for measuring an inclination angle, a method of measuring a minute angular displacement by converting a change in the position of a bubble sealed in a bubble tube into an electric signal ( Electronic angle measuring devices have been proposed and are being used.
As an electronic micro-angular displacement measuring device, a device for measuring an angle based on a change in resistance or impedance between electrodes arranged in a bubble tube (for example, see Patent Documents 1 and 2), There is a method of measuring the angle by optically detecting the amount of displacement (for example, see Patent Literature 3 and Patent Literature 4).
[0003]
[Patent Document 1] JP-A-6-258076 (page 2, FIG. 1)
[Patent Document 2] JP-A-9-250923 (Pages 2 to 3, FIG. 1)
[Patent Document 3] JP-A-9-280857 (Pages 2 to 3, FIGS. 1 to 3)
[Patent Document 4] Japanese Patent Application Laid-Open No. 10-332367 (Pages 2 to 3, FIGS. 1 and 2)
[0004]
Patent Literature 1 discloses that a conductive liquid and bubbles are sealed in a tubular member having a predetermined curvature, and an inclination angle is electrically measured based on resistance values of two electrodes immersed in the conductive liquid. I have.
[0005]
Patent Document 2 has a common electrode that is always immersed in an electrolyte and does not touch bubbles, and a plurality of surrounding electrodes that protrude higher than the common electrode and are immersed in the electrolyte so as not to touch bubbles in a horizontal state. In the horizontal state, the impedance between the surrounding electrodes has a ratio of a predetermined value, and it is disclosed that the inclination angle is electrically measured from a change in the impedance of the surrounding electrode when the device is inclined.
[0006]
Patent Document 3 discloses that a light emitting element is disposed on one side of a bubble tube in which liquid and bubbles are sealed, and two light receiving elements are arranged on the opposite side of the bubble tube along the longitudinal direction of the bubble tube. And the light emitted from the light emitting element is received by the two light receiving elements through the liquid or the air bubble sealed in the bubble tube, and the inclination angle is determined by the difference between the light receiving amounts of the two light receiving elements. Has been proposed.
[0007]
In Patent Document 4, in a dome-shaped bubble tube, light is irradiated from one direction in the vertical direction, and light passing through the bubble tube is received by a CCD element to output an image signal of an image corresponding to the bubble, It has been proposed to scan the image signal sequentially from two orthogonal ends to determine the center position of the bubble from the intersection with the outline of the bubble and calculate the tilt angle.
[0008]
[Problems to be solved by the invention]
The tilt angle measurement method disclosed in Patent Literature 1 or Patent Literature 2 is based on a change in resistance or impedance of a portion of an electrode immersed in an electrolytic solution. However, in such a method, errors due to expansion and contraction of the electrolyte caused by a change in ambient temperature, instability of the contact surface due to the surface tension of the electrolyte, and aging of the electrolyte can cause errors. Difficult to measure angles with high accuracy.
[0009]
Further, in the tilt angle measurement method disclosed in Patent Document 3 or Patent Document 4, an amount of light or an image which is emitted from a light emitting source and passes through a bubble and a liquid sealed in a bubble tube is detected by a light receiving element. This is a signal conversion method. However, even in these systems, the effects of expansion and contraction of the electrolyte caused by changes in the ambient temperature are not basically eliminated. For this reason, for example, the system disclosed in Patent Document 4 includes a pressure adjusting unit.
[0010]
In addition, there is a problem that a dead portion of the light receiving element due to the positional relationship between the light receiving element and the air bubble and an influence on a measurement error due to an insufficient light amount, and the like. For example, in the method disclosed in Patent Document 4, since the bubble tube has a dome shape (a shape in which a bowl is turned down), when a flat CCD device is used, the distance between the bubble and the CCD device changes. As the distance from the center of the dome increases, the image information becomes blurred. On the other hand, it is not practical to manufacture a curved CCD element along the dome shape because it is difficult and expensive. Furthermore, in the method disclosed in Patent Document 4, light must be incident from the upper surface of the bubble and light passing through the bubble and the liquid present on the lower surface of the bubble must be received. The change amount becomes small, and the image information of the bubble outline may not always be clear.
[0011]
An object of the present invention is to provide a high-precision electric inclination angle detecting device which is less affected by a change in ambient temperature and which has a problem in the prior art.
[0012]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a closed chamber having at least two opposing wall surfaces formed of a light-transmitting member, a liquid sealed so as to have bubbles in the chamber, A light source disposed on one of the two wall surfaces made of a light transmitting member, a CCD element disposed on the other wall surface side of the two wall surfaces made of the light transmitting member, and a CCD element A tilt angle measuring device having information processing means for calculating a tilt angle based on image information, wherein a boundary position between a bubble and a liquid on both sides of the bubble at a predetermined depth position is detected by the CCD element, and the detected bubble is detected. The center position of the bubble is calculated from the boundary position information of both sides, and the angle is measured based on the amount of displacement of the bubble from the reference position.
[0013]
In the present invention, as the light transmitting member, a transparent glass plate or a resin plate is usually used, but a known colored member or the like that can transmit light of the light source corresponding to the light of the light source to be used is used. can do.
In the present invention, the wall surface made of the light transmissive member is basically arranged so as to be parallel to the displacement direction surface at the measured angle. In the present invention, it is desirable that the wall surface made of the light-transmitting member is disposed close to the air bubble so that the side surface of the bubble does not become a free surface. By arranging in this way, both sides of the bubble are regulated to form two parallel sides and almost no liquid exists between the wall made of the light-transmitting member and the bubble. It is possible to more clearly detect the outline of the boundary between the bubble and the liquid at both sides of the bubble at the position (the front and rear ends in the bubble moving direction).
[0014]
In the present invention, among the wall surfaces forming the closed chamber, members forming the wall surfaces other than the two wall surfaces made of the light-transmitting member may be either a transparent body or an opaque body. However, it is important that a member constituting the wall surface of the upper surface of the bubble to which the bubble contacts and moves can be subjected to extremely precise processing. From such a viewpoint, it is desirable to use a metal member.
In other words, of the walls forming the closed chamber, at least the upper wall surface on which the bubble upper surface contacts and moves is such that the bubble is located substantially in the center at the reference position (usually when the inclination angle is zero). In addition, it must be precisely formed with a predetermined curvature in a curved shape depressed upward so that the bubble moves a predetermined distance at a predetermined angular displacement.
In the present invention, the shape of the chamber may be an arc (arc), a cylinder, or a column corresponding to the angle to be measured.
[0015]
In the present invention, as the liquid sealed in the closed chamber, a liquid commonly used in this kind of bubble tube, for example, a liquid obtained by adding potassium iodide to a mixed liquid of diethyl ether and ethyl alcohol, or the like is known. Can be used as appropriate.
[0016]
In the present invention, a CCD element in which pixels are arranged over a length range longer than a moving distance of a bubble moving within a measurement angle range is used. This CCD element is disposed substantially parallel to and close to the ridgeline of the upper wall surface. With this configuration, the displacement amount of the bubble can be obtained from the obtained CCD image information signal. In the case where the closed chamber has an arc shape or the like, it is difficult to arrange a linear CCD element along the ridgeline of the upper wall surface. Using a CCD element having a pixel array of a size to cover, select a pixel for detecting the boundary position on both sides of the bubble corresponding to the measurement angle, and set the boundary position at a substantially constant distance (bubble depth position) from the upper wall surface of the chamber. May be detected.
[0017]
As will be described in detail later, in the present invention, the position of the bubble is determined by detecting two points where at least one virtual line crossing the position of the predetermined depth in the bubble and the bubble-liquid boundary line intersect. For this reason, in principle, the pixel array of the CCD light receiving elements to be taken in with the pixel information may be one row, but a plurality of rows of pixel information may be taken in in order to improve the detection accuracy.
In the present invention, the position of the bubble is determined by detecting the boundary position between the bubble and the liquid at both ends of the bubble, and calculating the center position of the bubble from the boundary position at the both ends of the bubble. Therefore, even if the size of the bubble changes due to the influence of the ambient temperature or the like, the required center position of the bubble does not change, so that the influence of the ambient temperature, which has been a problem in the related art, can be extremely reduced.
[0018]
In the present invention, since the light-transmissive wall surface is configured so as to sandwich both sides of the bubble in parallel with the moving direction of the bubble, the moving direction of the bubble is basically defined and moved. . Therefore, only the angle in the direction to be measured can be accurately measured. Further, since the pair of light-transmitting wall surfaces are basically opposed to each other at an interval equal to or less than the free diameter of the bubble, relatively little liquid exists between the bubble and the light-transmitting wall surface. Therefore, there is a large difference between the amount (intensity) of light passing through the bubble portion and light passing through the liquid portion, and the boundary between the bubble and the liquid can be clearly recognized.
Further, since the light-transmitting wall surface has a flat plate shape, an inexpensive flat long CCD device having a simple structure can be used for both the light emitting element and the light receiving element. Further, since the distance between the bubble and the CCD light receiving element does not change, the reliability (accuracy) of the detected image information signal is high.
[0019]
The angle measuring device of the present invention first stores the center position of the bubble in the state of the reference angle (for example, a horizontal state where the airbag is not inclined) as a reference point. Next, the moving position of the bubble at a predetermined angle change is sequentially measured and stored in the storage circuit, and at the time of actual measurement, the angle is measured with reference to the stored and stored basic data.
For example, when the angle measuring device of the present invention is used by attaching it to the body of a surveying instrument, first, basic data is collected and stored in the attached state, and then actual measurement is performed. In addition, for example, the reference point and the center position of the bubble may not coincide with each other without tilting due to, for example, a change over time. In such a case, the position of the reference point may be appropriately adjusted as necessary. It is desirable to adjust.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 and FIG. 2 are a schematic configuration diagram and a configuration diagram of a detection unit according to an embodiment of the present invention. 1 and 2, reference numeral 1 denotes a base, and a substantially rectangular penetrating window 2 is formed at the center as shown in FIG. The upper wall surface of the window 2 is finished in a curved shape such that the bubble is recessed upward with a predetermined curvature so that the bubble is located substantially in the center at the reference position (usually when the angle is zero).
3a and 3b are flat members made of a light-transmitting material. In the present embodiment, the same material is provided on both side surfaces of the base 1, but different materials and shapes may be used.
[0021]
FIG. 1 is a schematic diagram illustrating the configuration of a detection unit according to the present embodiment. FIG. 1A is an elevation view shown by an aa cross section, and FIG. 1B is a side view shown by a bb cross section. Plate members 3a and 3b are closely adhered and fixed to both sides of the base 1 with an adhesive, and a closed substantially rectangular parallelepiped chamber 4 is formed. In this embodiment, the chamber has a substantially rectangular parallelepiped shape, but may have an arc shape (arc shape) or a cylindrical shape depending on the angle to be measured.
The closed chamber 4 is filled with a liquid 5 injected from an injection hole (not shown) so that bubbles 6 are formed and sealed. A light source 7 is attached to the outer surface of one wall surface 3a made of a light-transmissive material. The CCD element 8 is attached.
With the above configuration, light emitted from the light source 7 passes through the bubbles and / or liquid, reaches the CCD element 8, and is received. The light emitted from the light source 7 is preferably a parallel light beam if possible, but need not necessarily be a parallel light beam. Further, it is preferable to configure the closed room so that no incident light other than the light emitted from the light source 7 exists in order to reduce noise. In this embodiment, the light source 7 is specially mounted. However, in some cases, the light source 7 is not particularly provided, and ambient light may be used as the light source.
[0022]
The CCD element 8 is configured to be capable of receiving light at least over the entire moving range of the bubble moving along the upper wall surface of the closed chamber 4. That is, a pixel having a configuration in which pixels are arranged over a range equal to or longer than the entire length of the range in which bubbles move is used. The installation position is located on the outer surface of the window near the upper wall surface and in the longitudinal direction substantially parallel to the ridge line of the upper wall surface.
FIG. 3 is a conceptual diagram for explaining a method of measuring the bubble center position in the present embodiment. FIG. 3 shows, for convenience of explanation, the pixels of the CCD light-receiving element extremely large compared to the size of the bubbles, and arranges the pixels of the CCD element in a row substantially parallel to the upper wall surface 9 of the base 1. It is shown in a simplified manner.
In the figure, the bubble 6A is the position of the bubble at the reference angle, and the center position (that is, the reference position) corresponds to the position of the n-th pixel. Next, assuming that the bubble when inclined at the angle α is the bubble 6B, the moving distance L of the bubble 6B from the reference position is obtained as follows. The light emitted from the light source 7 passes through the bubble or liquid and is received by the CCD element 8. However, since the light transmittance is different between the bubble and the liquid, the light from the pixel corresponding to the bubble in the CCD element 8 is detected. There is a difference between the information signal and the detected information signal from the pixel corresponding to the liquid portion.
In order to simplify the explanation, in FIG. 3, the detection information of each pixel is binarized, the pixel receiving light passing through the liquid is indicated by a black circle, and the pixel receiving light passing through the bubble is indicated by a black circle. Is indicated by a white circle. As shown in the figure, a pixel receiving light passing through a bubble and a pixel receiving light passing through a liquid can be clearly distinguished.
[0023]
In FIG. 3, a pixel corresponding to the boundary position between the bubble and the liquid at the left end of the bubble B is denoted by P1, and a pixel corresponding to the boundary position between the bubble and the liquid on the right side is denoted by P2. Since the bubble is formed in a substantially circular arc shape due to surface tension, P1 and P2 are present at target positions with respect to the center position of the bubble. Assuming that the pixel P1 is the (n + m) th pixel and the pixel P2 is the (n + m + d) th (where d corresponds to the number of pixels existing between the pixels P1 and P2), the pixel corresponding to the center position of the bubble is n + m + d / It will be located second.
The moving amount of the bubble corresponding to the angle α is obtained by multiplying the number of pixels existing between the pixel corresponding to the center position of the bubble at the angle and the pixel corresponding to the center position of the bubble at the angle of zero by the pixel arrangement pitch. Can be obtained by That is, since the pixel position corresponding to the bubble center position at the angle α is n + m + d / 2, and the pixel position corresponding to the bubble center position at the angle of zero is n, the number of pixels existing between the two pixel positions is ( (n + m + d / 2) -n = (m + d / 2). Therefore, the moving distance of the bubble can be obtained by (m + d / 2) × p, where p is the arrangement pitch.
[0024]
FIG. 4 is a schematic configuration explanatory diagram of the information processing means 10 in the present embodiment. In the figure, 11 is an object to be measured, 12 is a detector, 13 is a CCD light receiving element provided in the detector 12, 14 is a CCD drive circuit, 15 is a pixel information recognition circuit, 16 is an arithmetic circuit, and 17 is a memory. The circuit 18 is a display means.
The CCD light receiving element unit 13 of the detection unit 12 attached to the angle measurement object 11 is driven by the CCD driving unit 14, and a detection information signal from each scanned pixel is input to the pixel information recognition circuit 15. The pixel information recognition circuit 15 processes the detection information signal from each pixel to recognize boundary position information on both sides of the bubble. The center position of the bubble is calculated by inputting the recognized boundary position information signal to the arithmetic circuit 16, and the moving amount of the bubble is calculated with reference to the reference position stored in the storage circuit 17 in advance. The angular displacement from the reference position corresponding to is obtained.
The output of the angle information signal obtained by the arithmetic circuit 16 is input to the display means 18 and the like, and the angle is displayed. Although not shown, the angle information signal output can be printed by inputting it to a printing means, or an alarm can be issued by inputting it to an alarm means.
[0025]
In the above embodiment, both the base and the light-transmitting member are flat, but the present invention is not limited to this shape. For example, the chamber of the base may be formed in an arc shape (arc shape), a cylindrical shape (ring shape), or a column shape. Also, various changes in shape are possible, for example, by providing a fitting portion that enables good coupling between the two members.
Further, the configuration of the information processing means in the present invention is not limited to the configuration shown in the above embodiment, and it goes without saying that various circuit configurations can be adopted as long as the operation and effect are not hindered.
As described above, in the present invention, since the positions of both ends of the bubble are detected and the center position of the positions of both ends is calculated as the center position of the bubble, the expansion and contraction of the bubble due to the ambient temperature is calculated. The position of the bubble, in other words, the angle, can be accurately measured without being affected.
[0026]
【Example】
An aluminum plate was processed to prepare a base 1 having a width of 40 mm, a length of 80 mm and a thickness of 8 mm having a window 2 having a width of 10 mm x a length of 40 mm x a depth of 8 mm. The upper wall surface of the window 4 is precisely processed and finished with a radius of 7 m using a wire saw. In addition, an injection hole penetrating to the window 2 was formed substantially in the center of one side surface of the base 1.
A colorless and transparent glass plate was used as the light transmitting material, and two flat plates 3 each having a width of 40 mm, a length of 60 mm, and a thickness of 2 mm were prepared. The two glass flat plates 3a and 3b were closely adhered and fixed to both surfaces of the substrate 1 using an adhesive to form a closed chamber 4 having two opposing surfaces formed of glass wall surfaces.
Next, a liquid obtained by adding potassium iodide to a mixture of diethyl ether and ethyl alcohol was injected from the injection hole until a bubble having a predetermined size was formed, and then the injection hole was sealed.
[0027]
Next, a planar light-emitting element 7 in which a plurality of light-emitting elements (LEDs) were arranged was fixed to the outside of one glass wall, and a CCD light-receiving element was fixed to the outside of the other opposite glass wall. As the CCD light receiving element, a linear image sensor KLI-2113 manufactured by Kodak was used. This CCD light receiving element has a pixel number of 2122 × 3 rows and a pixel size of 14 μm × 14 μm.
The light receiving element was fixed so that the pixel row of the CCD light receiving element was approximately 0.5 mm below the ridge line of the upper wall surface of the window 4 and substantially along the ridge line of the upper wall surface.
Next, the liquid 5 was injected from the injection hole, and the air hole 6 was formed in an appropriate size, and the injection hole was closed and sealed to form a detection unit.
[0028]
First, this bubble device is attached to the angle reference device, the center position of the bubble at zero inclination and the center position of the bubble at any angular displacement are measured in advance, and basic position information data on the correlation between the angle and the center position of the bubble. Was stored in the storage means. FIG. 5 is a correlation curve diagram of the angle and the movement amount of the center position of the bubble in the present embodiment. In the case of the present embodiment, it can be seen that the angle and the bubble movement amount have a substantially linear relationship.
Next, when the detection unit according to the present example was attached to a building member and the actual angle was measured, the angle could be measured with an accuracy of 0.01 mm / 1000 mm.
[0029]
【The invention's effect】
As is clear from the above description, since the present invention obtains the center position of the bubble from the both end positions of the bubble, the present invention captures the center position of the bubble regardless of the change in the size of the bubble due to the influence of the external temperature. Therefore, the effect of the external temperature can be extremely reduced. Further, since the light is emitted and received from the side surface of the bubble, the position of both side edges of the bubble can be detected very clearly, so that highly accurate angle measurement can be performed. For this reason, the angle measuring device according to the present invention can be applied to many applications that require precise angle measurement, such as measuring angles of building equipment and members at a building site or the like.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional explanatory view of a detection unit according to an embodiment of the present invention,
FIG. 2 is a partial explanatory view of a detection unit constituent member according to an embodiment of the present invention;
FIG. 3 is a schematic explanatory view showing an angle measuring method according to the present invention;
FIG. 4 is a schematic explanatory diagram of an information processing means according to an embodiment of the present invention;
FIG. 5 is a correlation diagram between an angle and a bubble movement amount in one embodiment of the present invention;
[Explanation of symbols]
1: base 2: window 3: light transmissive member 4: closed chamber 5: liquid 6: bubble 7: light emitting source 8: CCD light receiving element 9: upper wall surface 10: information processing means 11: angle measurement object 12 : Detection unit 13: CCD light receiving element unit 14: CCD drive circuit 15: pixel information recognition circuit 16: arithmetic circuit 17: storage circuit 18: display means

Claims (7)

At least two opposing wall surfaces have a closed chamber having a wall surface formed of a light-transmitting member, a liquid sealed so as to have bubbles in the chamber, and a two-wall surface formed of the light-transmitting member. A light source disposed on one wall side, a CCD element disposed on the other wall side of the two wall surfaces made of the light transmitting member, and information processing for calculating an angle based on image information of the CCD element Means for detecting the boundary position between the bubble and the liquid on both sides of the bubble at a predetermined depth position by the CCD element, and calculating the center position of the bubble from the detected boundary position information on both sides of the bubble. An angle measuring device for measuring an angle based on a displacement amount of the bubble from a reference position. The angle measuring device according to claim 1, wherein the air bubble has a parallel portion sandwiched between two wall surfaces made of the light transmitting member. 2. The angle measuring device according to claim 1, wherein, of the walls forming the closed chamber, walls other than the two walls made of a light-transmitting member are formed of a metal member. The angle measuring device according to claim 1, wherein the closed chamber has a substantially rectangular parallelepiped shape. The angle measuring device according to claim 1, wherein the closed chamber has an arc shape, a cylindrical shape, or a column shape. The angle measuring device according to claim 5, wherein the CCD element is arranged along an outer circumferential circle or an outer circumferential arc of the chamber. 7. The angle measuring device according to claim 5, wherein the image information of the CCD element is obtained from CCD pixels selected along an outer circumferential circle or an outer circumferential arc of the chamber.

Images