JPH02143111A - Angular displacement detector - Google Patents

Abstract

PURPOSE:To find angular displacement by a lightweight, small-sized device speedily with excellent sensitivity by detecting momentary shifts in the absolute position and relative position of a floating body by at least two detection parts. CONSTITUTION:At time (t) (0<=t<=t1), a slit image formed on the side of a photodetector 6 is close to the center of a light reception surface 6a, so a selecting circuit 16 employs the output signal of the photodetector 6. At t=t1, the levels of the element 6 and a light reception element 8 become equal and at t>t1, a slit image formed on the side of the element 8 becomes close to the center of a light reception surface 8a, so the selecting circuit 16 employs the output signal of the element 8. The output signal selected by this circuit 16 becomes discontinuous at t=t1. Therefore, the (A-B) output of a detecting circuit is differentiated 17 and inputted to the circuit 6 as a speed signal. This speed is irrelevant to the light reception surface slit images and the speed signals of the elements 6 and 8 are the same. Therefore, even when the circuit 16 is switched, the output signal is continuous and a signal which is integrated 18 indicates a real displacement signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a displacement detection device called a hydrostatic sensor, and more particularly to an improvement of the above-mentioned type of angular displacement detection device.

[Prior Art] When an object is placed in a floating state in a liquid sealed in a container, etc., and an image is applied to the container, the object is moved due to the buffering effect of the liquid and the inertial force of the object. A phenomenon occurs in which the object does not move at all but remains stationary in its original position. At this time, since the container, etc. is displaced relative to the object, the absolute displacement of the container, etc. can be detected by detecting the relative displacement between the container, etc. and the object. . A displacement detection device constructed based on this principle is called a hydrostatic sensor.
Conventionally, hydrostatic sensors for detecting angular displacements, such as those shown in FIGS. 9 to 11, are known.

In FIGS. 9 to 11, 101 is a base on which each part constituting the device is mounted, 102 is a cylindrical housing having a chamber in which 21 bodies 103 and a transparent liquid 104 are sealed; A groove portion 102a is formed in the inner circumferential wall surface of the groove portion 102a, into which a mouth-shaped floating body holder 114 shown in detail in FIG. 11 is fitted and fixed. 10
3 is a floating body, which is rotatably held by the floating body holder 11.4 around an axis 103a, and has a mirror 109 on both surfaces of a pair of side surfaces of the central block, and a slit 110a covering the mirror 109. A mask 110 is attached, and arm portions 103b extend from the other pair of sides of the central block. Note that this floating body 103 is configured to have a rotational balance around the axis 103a and a buoyancy balance within the liquid.

105 is an emitting element (IRED) that generates light when energized
It is fixedly attached to the base 101 by the issuing element holder 107. 106 is a light receiving element (PS) consisting of a photoelectric conversion element whose output changes depending on the position of the received light.
D), and is fixed to the base 101 by a photoelectric conversion element holder 108. These light emitting elements 1
05 and the light receiving element 105 constitute an optical angular displacement detection means of a type that transmits light via a mirror 109 attached to the surface of the center block of the floating body 103. Note that the light emitting element holder 107 is formed with a leading part 107a that guides the light from the light emitting element 105, and the tip of this light guiding part 107a is connected to the mirror +09 of the floating body 103.
A mask having the same slit 110a as the mask 110 covering is attached. Note that this optical transmission is performed using the housing 102.
Since this is carried out through the casing 102, the entire casing 102 or the corresponding portion is made of a transparent material.

The floating body 103 described above is supported in the following manner.

That is, the center block of the floating body 103 is provided with a rotating shaft 103a penetrating the upper and lower sides as shown in the cross-sectional view of FIG. 10, and pivots 112 having outwardly pointed tips are press-fitted into the upper and lower ends of the rotary shaft 103a, respectively. On the other hand, pivot bearings 113 are provided at the ends of the U-shaped upper and lower arms of the above-described floating body holder +14 so as to face each other inwardly.
The floating body 103 is supported by the sharp tips of the floating body 103 fitting into the pivot bearings 113.

Reference numeral 115 denotes a top lid of the housing 102, which is sealed and bonded to the housing 102 by a known technique using a silicone adhesive or the like. A rubber gasket 116 is sandwiched between the presser plate 117 and the upper lid 115, and is fixed to the upper lid with screws or the like.

119 and 120 are yokes for forming a magnetic circuit, one end of which faces the tip of the arm portion 1031) of the floating body 103a in order to stably fix the floating body 103 shown in the attitude shown in FIG. It is arranged as follows. Also,
Between the other ends of the yokes 119 and 120 is a yoke]21
and a coil 123 are coupled together, so that when the coil 123 of the electromagnet is energized, the yoke 121 - the yoke 1!9 - the floating body 103 - H-';'
120-IH1if1 stone-Noyoke 121 closed magnetic circuit is formed.

In the above configuration, the floating body 103 maintains a rotational balance around the axis 103δ as described above so that no rotational moment is generated due to the influence of gravity in any posture, and no load is substantially applied to the pivot axis. They are constructed so that the buoyancy within the liquid is balanced.

In this configuration, even if the housing 102 rotates around the rotation axis 103a, the inside of the liquid does not move due to inertia, so the floating body 103 in a floating state does not rotate, and therefore the housing 1
02 and the floating body 103 will rotate relative to each other around the rotation axis 103a. This is the principle of this device that detects relative angular displacement, and the relative angular displacement that occurs between them is
It can be detected by an optical detection means using the light emitting element 105 and the light receiving element 106 described above.

Note that a flow actually occurs inside the sealed liquid due to the influence of the wall surface of the housing 102, and this exerts a force on the floating body 103, but the effect is determined by taking into account the distance from the wall surface to the floating body 103, the viscosity of the liquid, etc. By selecting it, it is possible to make it as small as possible.

Now, detection of angular displacement is performed as follows in the apparatus having the above configuration.

First, the light emitted from the light emitting element 105 is transmitted to the light guide section 107.
a, the light is irradiated onto the floating body 103, where it is reflected by the mirror 109 and reaches the light receiving element 10B. As described above, since the mask 110 is disposed on the tip of the leading portion 107a and the mirror 109 of the floating body 103, the light is transmitted through the slit 11 of the mask 110 during the transmission of the light.
0a, the light becomes substantially parallel light, and an unblurred image (slit image) is formed on the light receiving element 106.

Then, the housing 102, the light emitting element 105. The light receiving elements 106 are all fixed on the base 101 and move together, so when a relative angular displacement movement occurs between the housing 102 and the floating body 103, the amount corresponding to the displacement occurs. The slit image above the light-receiving element 106 moves accordingly.

Therefore, the output of the light receiving element 106, which is a charging conversion element whose output changes depending on the position of the received light, is an output proportional to the positional displacement of the slit image, and the angular displacement of the housing 102 and the base 101 is detected by this output. be able to.

By the way, considering the angular displacement detection device configured above,
Since the floating body 103 is not receiving any external force, the attitude of the floating body 103 cannot be regulated.
In this case, there is no guarantee that the slit image will remain within the measurement range of the light receiving element 106.

Therefore, a method can be considered in which, for example, a permanent magnet or an electromagnet is used to apply a weak magnetic field to the floating body, and the floating body 103 is kept in the steady state position shown in FIG. 9 by this magnetic field action. In other words, a current is passed through the coil 123 to operate it as an electromagnet, and this magnetic field action causes the yoke 121 to yoke 1 to
19-Floating body 103-1-4120-7-ri121 <7
) A closed air circuit is formed to hold the floating body 103 in place. The biasing force exerted on the floating body by the action of this magnetic field is, in principle, a force that maintains the floating body 103 in a constant posture with respect to the housing 102 (that is, moves it together with the body 102), so if the magnetic field action is strong, the floating body 103 and floating body 103
move as a unit, leading to the problem that the relative displacement for the desired angular displacement does not occur, but if the magnetic field action is sufficiently small relative to the inertia of the liquid, it will respond even at relatively low frequencies. It can be configured as follows.

[Problems to be Solved by the Invention] However, the above-mentioned angular displacement detection device has the following problems:
3. It takes a relatively long time to stop the floating body localization device in a fixed position, so rapid detection cannot be performed. ■The coil 123 and yokes 119 and 120 that make up the floating body localization device are large, so the overall size is large. There were disadvantages such as the camera etc. would become bulky if mounted on a small device such as (1) sensitivity and accuracy to low frequency Sa was poor due to the magnet of the floating body positioning device.

Therefore, the object of the present invention is to avoid the above-mentioned disadvantages.
An object of the present invention is to provide an improved angular displacement detection device.

[Means for Solving the Problems] In the present invention, the floating body localization device is abolished, and instead of positioning the floating body at a fixed position every time an angular displacement is detected, the absolute position and relative position of the floating body are changed from moment to moment. The angular displacement detection device according to the present invention, which is characterized in that it detects angular displacement, does not require an operation to reset the floating body to a fixed position every time angular displacement is detected, so that detection can be performed quickly. In addition, since the angular displacement detection device of the present invention does not require an electromagnet or the like as a floating body localization device, it not only has good sensitivity and accuracy to low-frequency vibrations, but also has a small volume and light weight, so it can be used for compact devices such as cameras. It is now ready to be installed on the device.

In the angular displacement detection device of the present invention, in order to detect the position and relative displacement of the floating body, at least two detection units are arranged at positions apart from each other along the rotational direction of the floating body, and The relative displacement of the floating body can be detected regardless of the initial position of the floating body by using the detection unit to detect a large number of detected parts formed on the interlocking body. Therefore, the conventional floating body localization device is no longer necessary, and according to the invention, an angular displacement detection device that is lighter and smaller than the conventional angular displacement detection device and can perform detection quickly is provided. .

[Function] As shown in Fig. 2(b), the slit hole 2C of the floating body 2 is
When there are two light receiving elements 6 and 8, the selection circuit 1 in FIG.
6 is selected and output as a detected value of the relative rotational displacement of the floating body 2.

[Embodiment] The S1 embodiment of the present invention will be described below with reference to FIGS. 1 to 5.6 FIG. FIG. 2 is a plan view showing the relative positional relationship between the floating body and the detector in the first embodiment, and FIG. 3 shows the electrical configuration of the angular displacement detection device of the first embodiment. 4 and 5 are diagrams showing examples of signal waveforms in the electrical configuration of FIG. 3.

In FIGS. 1 and 2, 1 is a cylindrical housing in which a floating body 2 and a transparent liquid 3 are enclosed. The floating body 2 has cross-shaped arms, and is held by a floating body holder 4 so as to be rotatable around an axis 2a. In addition, the floating body 2 has a
A large number of slit holes 2 penetrated at equal intervals along the circumferential direction
The flange portion 2b has a flange portion 2b (that is, a detected portion). Note that this floating body 2 has an axis 2 similar to the conventional floating body.
It is constructed so that the rotational balance around a and the buoyancy balance within the liquid are respectively maintained.

Reference numeral 5 denotes a light emitting element (IRED) that generates light when energized, and is attached to the top cover (not shown), and constitutes an optical detection means in combination with a light receiving element 6 described below. 6 is a light-receiving element made of a PSD or the like, and has a light-receiving surface 6a;
It is configured so that the output changes depending on the position of the light incident on the light receiving surface 6a, and is attached to the housing 1. That is, the light emitted from the light emitting element 5 is emitted from the slit hole 2C.
A slit image is formed on the light receiving surface 6a of the light receiving element 6, and the light receiving element 6 generates an electrical output corresponding to the position of the slit image. 7 is a light emitting element with the same structure as 5 above,
It forms an optical position detecting means in pair with the light receiving element 8 shown in FIG.

The light emitting element and the light receiving element are arranged in a positional relationship as shown in FIG. 2 with respect to the flange portion 2b of the floating body 2.

That is, the light-receiving surface 6a of the light-receiving element 6 is shifted by - with respect to the interval α between the slit holes 2c of the flange portion 2b. In the state shown in FIG. The image is located, and therefore the position is detected based on the information from the light receiving element 6. FIG. 2(b) shows the floating body 2 rotated counterclockwise by a predetermined angle from the position of FIG.
However, when focusing on the light-receiving surface 8a, other slit images come closer to the center of the light-receiving surface 8a. Then, at a certain point, the slit image on the light receiving surface 8a becomes closer to the center than the slit image on the light receiving surface 6a.

In such a state, position detection is performed based on information from the light receiving element 8.

FIG. 3 shows the electrical configuration and detection signal processing means of the angular displacement detection device of this embodiment.

In Fig. 3, 13 takes in the outputs A and B of the light receiving elements 6 and 8 (the light receiving elements 6 and 8 simultaneously receive the two outputs A and 8).
and B)) and a detection circuit that generates an output (A+8) and an output (^-B).

12 is a light emission level detection circuit that detects the magnitude of the driving current of the light emitting elements 5 and 7; 11 is a light emitting circuit that drives the light emitting elements 5 and 7; 14 is a received light level detection circuit;
The circuit 14 generates an output that controls the light emitting circuit 11 to reduce the amount of light emitted from the light emitting elements 5 and 7 when the output (A+B) of the detection circuit 13 is higher than the reference level of the reference level setter 15. , the output of the detection circuit 13 (A+8)
When the reference level is smaller than the set level of the one-bell setter 15, an output is generated to control the light emitting circuit 11 so as to increase the amount of light emitted from the light emitting elements 5 and 7.

17 is a differentiation circuit that differentiates the output (A-8) of the detection circuit 13; 16 is a differential circuit that differentiates the output (A-8) of the detection circuit 13; and 16, based on the output (^-6) of the detection circuit 13, which of the slit image in the light receiving element 6 and the slit image in the light receiving element 8 is the center 18 is an integration circuit that integrates the output of the selection circuit 16; It is.

In FIG. 3, the detection circuit 13. The operations of the differentiating circuit 17 and the selecting circuit 16 will be explained with reference to FIG. First, consider the state shown in FIG. 2(a). In this case, when focusing on the light receiving element 6, the slit image is located approximately at the center (A-8), so the output is approximately male. On the other hand, when focusing on the light receiving element 8, there is no slit image at the center, but there are slit images at both ends of the light receiving surface 8a, so the center of gravity of the image is at the center of the light receiving surface, and the (^-B) output is The slit image becomes almost zero, as if it were in the center. In this case, the light-receiving element 8 receives two slit images, so the light-receiving level (^1B) increases, and as mentioned above, the feedback action of the light-receiving level detection circuit 14 works to prevent the light-receiving level from changing. As a result, the received light level decreases. The output of the light emission level detection circuit 12 is sent to the thousand angle circuit 16.
The selection circuit 16 determines the above-mentioned state from the input, and selects not to adopt it if the light emission level is low even if the (^-B) output is close to zero.

Next, the outputs of the light receiving elements 6 and 8 and the operation and output of the selection circuit 16 will be specifically explained with reference to FIGS. 4 and 5.

In Fig. 4, the horizontal axis shows time t and the vertical axis shows the (^-B) output. Fig. 4 (a) shows the output signal of the light receiving element 6, and Fig. 4 (b) shows the output signal of the light receiving element 8. The output signal, FIG. 4(C) shows the output signal selected by the selection circuit 16, 0≦t≦t,
Since the slit image formed on the light receiving element 6 side is close to the center of the light receiving surface 6a, the selection circuit 16 adopts the output signal of the light receiving element 6. 1=1. When the signals of the light receiving elements 6 and 8 are at the same level, and 1>1, the slit image formed on the light receiving element 8 side is close to the center of the light receiving surface 8a, so the selection circuit 16 selects the output signal 8 of the light receiving element 8. Adopt the number.

Therefore, the output signals selected by the selection circuit 16 are 1-1. as shown in FIG. 4(c). It becomes discontinuous at , and is detected as if a sudden displacement had occurred. Therefore, the (^-B) output of the detection circuit 13 is differentiated by a differentiating circuit 17 and sent to the selection circuit as a speed signal. Regardless of the position of the light-receiving surface slit image, the speed signals of the light-receiving elements 6 and 8 are the same. Therefore, even if switching is performed by the selection circuit I6, the speed signal output is continuous, and the speed signal is then transferred to the integrator circuit 1.
8, a continuous true displacement signal is obtained as shown in FIG.

As is clear from the above description, according to the present device, the displacement of the floating body can be detected no matter where the floating body is located, and the conventional floating body localization device is no longer necessary.

FIG. 6 is a plan view of the mechanical structure of the angular displacement detection device according to the second embodiment of the present invention.

In FIG. 6, 201 is a cylindrical floating body having a hollow part 201a, and its outer peripheral part has a plurality of flat parts 20 forming a regular polygon.
1b is formed, and a slit-shaped reverse slope 201C, which is a detected portion, is provided in the center thereof, and is held by a floating body holder (not shown) so as to be rotatable around an axis 201d. 202 and 204 are light emitting elements, 203 and 20
5 is a light receiving element (PSD), and the pixel element performs the same function as in the first embodiment.

In this embodiment, the slit-shaped reverse slope 2 which is the detected part
0] e are provided in plural numbers at equal intervals in the circumferential direction at pitch α, and the combination of light emitting and receiving elements, 202-203, 20
4-205 is arranged so as to be out of phase by - with respect to the pitch α of the slit-shaped reverse slope 201c. Then, the light beam emitted from the light emitting element passes through the slit-shaped reverse slope 20.
''C, a slit image is formed on the light receiving element.

The electrical configuration of the device of this embodiment is the same as the electrical configuration of the device of the first embodiment shown in FIG. Since it is the same as the apparatus of the embodiment, the operation of the apparatus of this embodiment is also the same as that of the apparatus of the first embodiment. Therefore, explanation regarding the operation of the apparatus of this embodiment will be omitted.

Note that the slit-shaped reverse slope 201c may be formed by a processing method such as aluminum vapor deposition or selective etching of an aluminum film.

FIG. 7 is a plan view showing the relative positional relationship between the floating body and the detection element in the angular displacement detection device according to the third embodiment of the present invention, and FIG. 8 is the electrical configuration of the angular displacement detection device according to the third embodiment. This is a diagram showing.

In FIG. 7, reference numeral 301 is a floating body with cross-shaped arms, which is rotatably held around an axis 301a, and has slit holes 301c provided at equal intervals in the circumferential direction at one end of the floating body. It has a flange portion 301b provided therein. 302, 303, 304 are light receiving devices (PSD),
Numerals 305, 306, and 307 are light emitting elements, which perform the same functions as in the first embodiment.

In Fig. 8, 308 is a light emitting circuit that causes a current to flow through the light emitting element to emit light, and 309 is the output from the light receiving element (^1B).
A detection circuit 310 calculates (^-B) and compares the (^1B) output of the detection circuit with the reference level and (^+a).
This is a received light level detection circuit that provides an output to the light emitting circuit so that the level is constant.

The device of this embodiment having the above configuration also has almost the same functions as the first embodiment, but the difference between the device of this embodiment and the device of the first embodiment is the configuration of the position detection means. There are three sets of light emitting/receiving elements. As shown in FIG. 7(8), the light-receiving elements 302, 303, and 304 are arranged at the pitch interval α of the slit hole 301c, which is the detected portion, and are arranged with a phase shift of −α. In the figure, the slit image is located approximately at the center of the light receiving surface 302a, and therefore the (A-B) output is the smallest, and the selection circuit 3
12 selects and outputs position information of the light receiving element 302;

Figure (b) shows a state in which the floating body 301 has been rotated counterclockwise by a predetermined angle from the position of (a). Focusing on the light receiving element 304, the slit holes 301c are spaced at approximately equal intervals from the center of the light receiving surface 304a at both ends. , but does not cover the light-receiving surface 304a, that is, there is no slit image on the light-receiving surface 304g.In other words, in the configuration of this embodiment, two slit images exist on one light-receiving surface at the same time. Since there is no
A situation in which the center of gravity of the composite image of the two slit images is near the center of the light-receiving surface does not occur, so there is no need for a circuit for determining such a situation. Therefore, in this embodiment, the light emission level detection circuit can be omitted as shown in FIG. 8, and the configuration of the selection circuit 312 can be made simpler than that of the first embodiment.

[Effects of the Invention] As explained above, the angular displacement detection device of the present invention has the following effects:
Since there is no floating body positioning device to keep the floating body stationary in a fixed position, it is smaller in volume and lighter in weight than conventional devices, and it also requires more time to position the floating body in a fixed position and keep it stationary. Since there is no floating body localization device, it can be detected quickly, and since there is no floating body localization device, it is possible to obtain various effects such as increased sensitivity and accuracy to low frequency vibrations.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the mechanical structure of the angular displacement detection device according to the first embodiment of the present invention, and FIG.
b) is a plan view showing the relative positional relationship between the floating body and the detection means in the angular displacement detection device of FIG. 1, and FIG. 3 is a plan view of the angular displacement detection device of the first and second embodiments of the present invention. Diagram showing the electrical configuration, Figure 4 (a), (b), (c)
5 shows the output of the position detection element in the angular displacement detection device of the first embodiment and the output of the angular displacement detection device, and FIG. 6 shows the angular displacement detection of the second embodiment of the present invention. 7(a) and 7(b) are plan views showing the relative positional relationship between the floating body and the position detection element in the apparatus, and FIGS. FIG. 8 is an exploded perspective view of essential parts of the angular displacement detection device detection device of the third embodiment. 1... Housing 2... Floating body 2C... Slit hole 3... Transparent liquid 5-7... Light emitting element 6-8... Light receiving element 11... Light emitting circuit 12... Light emitting level Detection circuit 13...Detection circuit 14...Light reception level detection circuit 16...Selection circuit and 4 others Fig. 2 Fig. 1 Fig. 7 Fig. 10 Fig. 11

Claims (1)

[Claims] 1. A housing in which a liquid is sealed, a floating body that is placed in the liquid, is held rotatably around a specific axis, and is provided with a plurality of detected parts at equal intervals in the circumferential direction, and the floating body at least two detectors provided on the housing at different positions along the rotational direction of the housing, and an output that generates an output representing a change in the relative position of the floating body with respect to the housing based on the output of each of the detectors. An angular displacement detection device comprising: means.