JPS62233770A - Accelerometer - Google Patents

Abstract

PURPOSE:To equalize accelerometer for both axes in sensitivity by enabling a displacement pickup to detect the displacement of a pendulum regarding two orthogonal hinge axes. CONSTITUTION:The pendulum 1 is formed of a cylindrical body and a hinge consists of two continuous hinge parts 2-1 and 2-2 which are separated from each other in the direction of the pendulum axis Z of th pendulum 1 and cross each other at right angles. Then, the displacement pickups 58, 59, and 60 are enabled to detect the displacement of the pendulum regarding the two orthogonal hinge axes and a torquer consists of couples of torquers 56a, 56c, and 54, and 56b, 56d, and 55 regarding the two hinge axes.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an accelerometer, and particularly to a servo-type accelerometer having 21 mutually orthogonal input axes.

[Conventional technology]

Conventionally, this type of accelerometer has, for example, a sixth and a seventh accelerometer.
There is something like the one shown in the figure. In the figure, (1) is a rod-shaped pendulum that detects acceleration, and this has thin parts (2),
That is, it is supported by a flexible joint or hinge (3) having a flexible part. This pendulum (11) is parallel to the paper surface of FIG. 6 (X-
It can only rotate in the X') direction. One end of the hinge (3) is
Hinge mounting portion (5) of first base or frame (4)
It is securely attached via the hinge retaining slope (6), for example, with screws or the like. Also, the pendulum (1) has 2
ft! if cylindrical torquer coil (7), (7A)
is the rotation axis of the thin part (2) of the hinge (3), that is, (0-0
) A disc-shaped permanent magnet (8) and a cylindrical pole piece (9) installed perpendicularly to the axis are inserted into one of the torquer coils (7) without touching it. It is attached to the first frame (4) by, for example, an adhesive so that it can be seen. Since this first frame (4) is made of a material with high magnetic permeability such as electromagnetic soft iron, it forms a magnetic circuit with the pole piece (9) using a permanent magnet (8). It serves as a yoke (return path), and together with the torquer coil (7),
It constitutes one torquer.

This first frame (4) has an opening (4-2>,
(4-3), these are flowering (4-2), (4
-3) is equipped with two light-receiving elements (
10) A cylindrical holder (29) to which the (IOA) is fixed and a cylindrical lamp holder (28) to which the light emitting element (11) is fixed are inserted, respectively, and the deflection is detected together with the pendulum (1). configuring the device.

On the other hand, the second base or frame (12), like the first frame (4), is made of high magnetic permeability electromagnetic soft iron or the like, and does not come into contact with the torquer coil (78) and is As shown in the figure, a magnetic circuit is formed between the permanent magnet (13) and the pole piece (I4) bonded to the second frame (12), and serves as a yoke. Therefore, the torquer
Coil (7^), permanent magnet (13) and pole piece (
14) constitutes the other torquer. The first frame (
The fitting part (16) of the second frame (12) is inserted into the fitting part (15) of 4) to integrate the two.

Light receiving elements (10) and (10^) that constitute the deflection detection device
), etc., and the torquer coil (7).

Connect the external terminal (22) such as a lead wire (not shown) for supplying feedback current to the terminal case (7^).
23) in an airtight structure, and the terminal case (23) is attached to the first frame (4) such that the open end of the terminal case (23) is inside the first frame (4).
). The electrical system of the internal device is connected through the central opening (24) of the terminal case (23), and the inside of the chamber created by the first base (4) and the terminal case (23) is connected. 1.1ff (25) is glued to the opening (24) while vacuum or filling with inert gas (e.g. helium gas), etc., and the interior of the chamber is kept in an airtight state,
Prevents component deterioration and maintains stable performance over a long period of time.

When acceleration is applied to the accelerometer configured as described above in the direction of the central axis (X-X') of the first frame (4), the pendulum (1) uses the thin part (2) of the hinge (3) as a fulcrum. As a result, the light is slightly deflected, is shielded or split by the pendulum (1) from the light emitting element (11), and the light incident on the light receiving elements (lO) and (10^) of the deviation detector changes. An electrical signal corresponding to the deviation can be obtained. A current proportional to this electric signal is fed back to the torquer coil (?), (7A), thereby controlling the pendulum (1) to the light receiving element (
10) and (IOA) are restrained so that their electrical signal outputs become zero. Since this electric signal, that is, the restraining current, is proportional to the acceleration, the input acceleration can be determined by measuring this current.

In FIG. 7, (19-3) is the flange portion (4) of the first frame (4) used when attaching the above-mentioned accelerometer to the object whose acceleration is to be measured. This is the mounting hole provided in -1).

FIG. 8 is a perspective view of the conventional accelerometer deflection detection device shown in FIGS. 6 and 7. FIG. In FIG. 8, the lamp holder (28) is inserted and fixed into the opening (4-3) provided in the first frame (4) shown in FIGS. 6 and 7. The central axis of the lamp holder (2 days) is indicated by (R-R). On the other hand, the lamp holder (28) into which the light emitting element (11) is inserted
) or the central axis of the opening (28-1) provided in the light emitting element (
The optical axis (S-5) of 11) is parallel to the axis (R-R) of the lamp holder (28), and in this example, is eccentrically located upward by ε. Therefore, the light emitting element (1
By rotating the lamp holder (28) integrated with the lamp holder (28) around the axis (R-R) using its slot (2B-2), the optical axis ( S-
S) can be moved by a minute amount in the direction (X-X') in the figure, that is, in the vibration direction of the pendulum (1) perpendicular to the axis of the pendulum (1).

- On the other hand, the two light-receiving elements (10) and (10Δ) are connected to an opening (29-1) and ( 29-2) and then the holder (29) is inserted and fixed into the opening (4-2) of the first frame (4). Therefore, the light-emitting and light-receiving elements (11), (10), and (108) face each other via the free end of the pendulum +11, which functions as a light shielding part. Note that (29-3) is a slot provided on a cylindrical holder (29) similar to the slot (28-2).

Light emitting and light receiving elements (11) and (10), (IO
As shown in Figure 9, which shows the relationship between A) and the pendulum (11), the pendulum (
When the center (01) of 1) is located at a position that coincides with the center line (0'-0') connecting the optical axis of the light emitting element (11) and the center of the optical axis of the light receiving element (10), (IOA), The luminous flux (B) emitted from the light emitting element (11) is divided equally by the free end of the pendulum (11) between them, which acts as a light shielding part.
Approximately half of the light-receiving surfaces of the two light-receiving elements (to) and (IOA) are equally irradiated, although not less than the entire surface.

Therefore, the voltage appearing at the differential output terminals (A), (A!) derived from the light receiving elements (10), (IOA'') is zero. In other words, the state shown in FIG. This is the zero position.

However, for example, if acceleration acts and the pendulum +11 deviates from the position shown in FIG. 9 in the (X) direction in the same figure, the amount of light hitting the light receiving element (10) will be
The amount of light hitting the differential output terminal (A) is greater than that of the differential output terminal (A).
A voltage corresponding to the deviation of the pendulum +11 is generated between (A1) and functions as a deviation detection device.

By the way, normally, the zero position of the pendulum (1) is the light emitting element (11) and the light receiving element (10), (10
It is not necessarily on the center line (0'-0') of ^), and
Due to variations in the characteristics of the light receiving elements (10) and (10^), even when no acceleration is applied to the pendulum (1),
Since an output voltage is generated between the output terminals (A) and (A1), the device's output voltage is 1! At stage -C1 it is necessary to adjust this to zero.

In the conventional accelerometer shown in FIGS. 6 and 7, the lamp holder (28) is capable of small angle rotation as described above. As shown in Figure 1O, the lamp holder (28) or holder (29) is aligned with the axis (R-
R) in the direction of arrow +a), and its light emitting element (
11) Alternatively, it is possible to adjust the zero position of the deflection detection device by moving the light receiving element (10), (10^) to the left or right according to the zero position of the pendulum (11).

[Problem that the invention seeks to solve]

Accelerometers are often used to detect the inclination of the surface of a plant platform or moving object supported by a gimbal mechanism, etc. In this case, the conventional uniaxial accelerometer described above is used. It is necessary to mount the input shaft parallel to the mounting surface to be detected and perpendicular to each other.
Using more than one input shaft increases the size, weight, and cost of the device, and there are other problems such as the need for members and adjustments for mounting the input shafts so that they are orthogonal to each other. or,
If an attempt was made to make a two-axis integrated accelerometer, the disadvantage was that the structure of the hinge would be complicated.

[Means for solving problems]

Therefore, the main purpose of the present invention is to eliminate the above-mentioned conventional problems, and its means include a base (4) and a base (4).
4) a displacement big amplifier for detecting the displacement of the pendulum (11 and the pendulum +1 relative to the base (4)) supported via a hinge with respect to the hinge axis of the hinge; In an acceleration mechanism having a pendulum (a torquer that applies a torque proportional to the input current to 11), the pendulum (1) is formed from a cylindrical body, and the hinge is connected to the pendulum axis (Z) of the pendulum +1. Hinge axes (X) that are spaced apart from each other in the direction and orthogonal to each other.

(Y) Two consecutive hinge parts (2-1).

(2-2), the displacement pickups are configured of two orthogonal displacement pickups (58) each capable of detecting the displacement of the pendulum (1) with respect to the hinge axis of the IIN;
(57).

(60), and the torquer is connected to two torquers (50a) and (50a) related to the two hinge shafts.
0c).

(54) and (5Qb), (50d),
(55) This is an acceleration needle characterized by being constructed from (55).

C action] When acceleration is applied to the acceleration needle of the present invention, the pendulum (1)
The first hinge part (2-1> or the second hinge part (2-1)
-2) An angular displacement occurs around the light emitting element (5B
), a displacement pickup system consisting of a condenser lens (57) and a light receiving element (60) detects the light as components in the (X) and (Y) directions. Although the current corresponding to this is not shown,
The first torquer coil (54
) and the second torquer coil (55), the pendulum (1
) is fed back so that the angular displacement becomes zero. At this time, by measuring the current flowing through the torquer coils (54) and (55), the acceleration in the (X) direction and (Y) direction can be detected.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a sectional view showing an embodiment of an accelerometer according to the present invention. In this figure, the same reference numerals as in FIGS. 6 and 7 indicate the same elements.

In the example of the present invention shown in FIG. The attachment part (1-1) at one end of the pendulum (1) is inserted and fixed.The pendulum (1) is attached to the first and second hinge parts above the attachment part (1-1>). (2-1)
and (2-2). As shown in Fig. 2, the first hinge part (2-1) is formed by cutting out opposite sides of a cylindrical pendulum (1) in a semicircular arc shape, and the center thereof is the thinnest hinge axis (X). This hinge axis (X) is perpendicular to both the paper plane of FIG.
2-2) also has a first hinge portion (2-2) as shown in FIG.
1'), its hinge axis (Y) is the same as the hinge axis (X) and pendulum axis (Z) of the first hinge part (2-1>).
In the pendulum axis (Z) direction, the hinge axis <
It is 2 points above X>.

Further, as shown in FIG. 1, the pendulum (1) has a first torquer coil (54) and a second torquer coil located above the second hinge portion (2-2) and in the center thereof. (55) is attached to the coil support member (56). The first and second torquer coils (54) and (55)
) is also the distance between the centers in the pendulum axis (Z) direction of the first and second hinge parts (2-1).

(2-2) The pendulum axis (
Z) direction is set to a value equal to the distance Kl (see FIG. 3). Further, a condenser lens (57) is inserted and fixed into the upper end of the cylindrical pendulum +11, as shown in FIG. Inserted and fixed.

A cylindrical second base (12) whose upper end is closed is fixed to the first base (4) with machine screws or the like.

As shown in Figure 3, the first and second torquer coils (5
4), (55) are wound into a thin rectangular shape, and the first
The center line of the pair of long sides of the torquer coil (54) is parallel to the hinge axis (Y) of the second hinge part (2-2),
The center lines of the pair of H sides of the torquer coil (55) are parallel to the hinge axis (X) of the first hinge part (2-1). Additionally, the torquer magnets (50a), (50c) and (50b) having a U-shaped side surface as shown in FIG.
, (50d'), both torquer coils (54)
.

(55) arranged so as to sandwich the pair of short sides (Fig. 1),
These are, as shown in FIG. 4, slits (12-18) to (12-18) provided in the cylindrical part (12A) of the second base (12) at an angular interval of approximately 90°. 10), each is fixed with a small screw or the like so as to have the above-mentioned relationship (in FIG. 4, the slit (12-1^)).

(12-IB) is not visible).

Each of the torquer magnets (50a) to (50d) consists of a square permanent magnet (51) and two short mt-shaped yokes (52) attached to sandwich this from above and below.
, (53). The magnetic flux produced by the permanent magnet (51) is indicated by (φ) in FIG.

As shown in FIG. 1, the closed part (12) of the second base (12)
B) has a mounting base (60) on its upper surface.
63), is installed. In this case, the light emitting element (5B)
, the mounting base (63) is arranged so that the optical axes of the light receiving element (60) and the condensing lens (57) are aligned with each other.

(12G) is a central opening bored in the center of the closing part (12B), through which the condensing lens (
57) extends toward the light receiving element (60), and the gap between the inner edge of the central hole (12G) and the pendulum (1) is connected to the first and second hinge parts (2-1) and (2-2). By setting it within the stress limit of , it is operated as a stopper for the pendulum (11).

In FIG. 3, (56a) to (56d) are terminals provided on the coil support member (56), to which the winding ends of the first and second torquer coils (54) and (55) are connected, respectively. The flexible electrical circuits (67a), (67b) and (67c) shown in FIG.
, (67d) are connected to each other. On the other hand, (4a) to (4d) in Fig. 1 are the first base (4).
The above-mentioned IS''ATi path (67
The other ends of a) to (67d) are connected to each other, and the output end of an externally installed control amplifier is also connected, although not shown.

A hinge part (2-1) of a pendulum (1) made of a cylindrical body.

Make (2-2) as thin as possible, around the (X) axis or (Y) axis (around the hinge axis (X) or (Y))
It is essential to reduce the torque spring constant of the accelerometer in terms of performance as an accelerometer. By making these hinge parts have the structure shown in FIG. 2, the hinge part (2-1) can withstand torsion around the pendulum axis (Z) while keeping the torque spring constant small.

The strength of (2-2) can be increased.

FIG. 5 is a diagram explaining the principle of a displacement pickup system consisting of a light emitting element (5B), an I-light lens (57), and a light receiving element (60). The light-receiving element (60) includes four light-receiving elements arranged in a square shape, or a light-receiving surface (60a) to (60d).
), and when no acceleration is acting on the device, the light from the light emitting element (58) is focused by a condenser lens (57) into a focal spot that uniformly illuminates each light receiving surface (60a) to (60d). becomes. Now, when acceleration is applied to the device and the pendulum (11) is displaced relative to the first base (4), etc., the condensing lens (57) attached to the pendulum (11) also changes in the same way, and the light emitting element (58 ) is connected to a point on the light receiving element (60) at a position moved by an amount proportional to the displacement of the condensing lens (57).

As a result, the light receiving surface (60a), (60c) or (60b).

A difference occurs in the area of the light hitting (60d), and this difference is extracted to the outside as a corresponding voltage signal.

Now, when acceleration is applied to the accelerometer of the present invention described above,
Angular displacement occurs in the pendulum (1) around the first hinge part (2-1) or the second hinge part (2-2), and this is caused by the light emitting element (58), the condensing lens (57), and the light receiving element. Motoko (60
) is detected as components in the (X) and (Y) directions. Although this corresponding electrical signal is not shown, it is further transmitted through a flexible electrical line (67a) via an external control amplifier.
) to (67d), the first torquer coil (5
4) and the second torquer coil (55), the pendulum (
1) Feed back so that the angular displacement becomes zero.

At this time, by measuring the current flowing through the torquer coils (54) and (55), the (X) direction and (Y) direction acceleration can be detected.

〔Effect of the invention〕

According to the present invention, the following effects can be obtained.

(1) One accelerometer can detect acceleration in two orthogonal axes (hinge axis (X) and (Y) directions).
- Compared to using two axial acceleration molds, size, weight, cost, etc. can be significantly reduced.

(2) By providing two hinge parts at the end of a pendulum made of a cylindrical body with hinge axes that are orthogonal to each other with a distance Mul in the longitudinal axis of the pendulum, it can be used as an accelerometer. The processing and assembly of the hinge, which requires the most skill, becomes highly precise and simple.

(31) Torquer for (X) axis direction and (Y) axis direction,
By arranging the two hinge parts at a distance equal to the distance Nl in the direction of the hinge axis in the direction of the pendulum axis (Z), even though a hinge with a simple structure is used, (
The sensitivities of the torquers around the

(Y) The sensitivity of the accelerometers on both axes can be made the same.

(4) Construct the pendulum with a hollow member such as a pipe, and attach it to (2
By configuring the two thin plate-like hinge portions described in section ), the strength around the single axis (Z) can be maintained without increasing the spring constant of the hinge.

(5) A simple and easy-to-manufacture torquer can be created by attaching two rectangular and thin plate-shaped coils to the pendulum with a distance fql of the two hinge axes apart in the pendulum axis (Z) direction. 1q is possible.

(6) Construct a pendulum with a cylindrical body, attach a condensing lens to its tip, and attach a light emitting element to the attachment end of the pendulum, while attaching two orthogonal axes to the position on the base side corresponding to the tip of the pendulum. A highly accurate displacement pickup can be obtained by attaching a light receiving element that detects movement of a light spot in a direction.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of an accelerometer according to the present invention;
Figure 2 is an enlarged perspective view of the hinge part, Figure 3 is a perspective view of the torquer coil, Figure 4 is an exploded view of the torquer magnet and second base, and Figure 5 is an explanatory diagram of the displacement pink amplifier. , FIG. 6 is a longitudinal cross-sectional view of a conventional acceleration needle, FIG. 7 is a cross-sectional view thereof, FIG. 8 is a perspective view of its big amplifier section, and FIGS. 9 and 10 are diagrams explaining its principle. In the figure, (1) is a pendulum, (2-1”), (2
-2) are the first and second hinge parts, (4) is the first base, (12) is the second base, (50a) to (50d
) is a torquer magnet, (54) and (55) are torquer coils, (57) is a condenser lens, (58) is a light emitting element, and (60) is a light receiving element, respectively.

Claims (1)

[Claims] a base; a pendulum supported by the base via a hinge;
An accelerometer that includes a displacement pickup that detects a displacement of the hinge of the pendulum with respect to the base with respect to the hinge axis, and a torquer that applies a torque proportional to an input current from the base to the pendulum. The pendulum is composed of two consecutive hinge parts having hinge axes that are spaced apart from each other in the direction of the pendulum axis and are orthogonal to each other, and the displacement pickup is capable of detecting displacement of the pendulum with respect to the two orthogonal hinge axes. What is claimed is: 1. An accelerometer comprising a displacement pickup and said torquer comprising two torquers related to said two hinge shafts.