JPH052861Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an accelerometer, and more particularly, to an accelerometer in which a detection device corresponding to acceleration is passed through a torquer coil to servo a pendulum.

Prior Art FIGS. 5A, B, and C show a front view, a side view, and a cross-sectional view of essential parts of an example of a conventional accelerometer, respectively.

In FIGS. 5A, B, and C, 10 is a pendulum. A rotating shaft 11 fixed to the pendulum 10 is rotatably supported by bearings 14 and 15 of frames 12 and 13, respectively. A light-shielding pin 16 as an optical path regulating member is fixed to the pendulum 10, and rotation of the pendulum 10 is restricted to the extent that the light-shielding pin 16 abuts stoppers 17 and 18 fixed to the frame 12, respectively.

The frames 12 and 13 are fixed to each other by supports (not shown), a light receiving element 20 is fixed to the frame 12, and a light emitting element 21 is fixed to the frame 13 facing the light receiving element 20. . A light shielding pin 16 is disposed between the light receiving element 20 and the light emitting element 21. The light receiving element 20 is divided into two parts, a light receiving part 20a and a light receiving part 20b. A ring-shaped torquer coil is fixed to the pendulum 10 in a balanced manner so that the light-shielding pin 16 is positioned on the boundary line between the light receiving sections 20a and 20b when the pendulum 10 is stationary.

A permanent magnet 2 is placed on the frame 12 which is a ferromagnetic material.
2 and 23 are fixed with their S poles in contact with each other. A yoke 24 made of a ferromagnetic material formed into a plate shape is installed and fixed on the N pole of each of the permanent magnets 22 and 23. The yoke 24 is inserted in a non-contact manner through the center hole of a ring-shaped torquer coil 25 fixed to the pendulum 10, and between the permanent magnets 22 and 23, lines of magnetic force are directed from the yoke 24 toward the frame 12. The above permanent magnets 22, 23, frame 12, yoke 2
4 and the torquer coil 25 constitute a torque generating device, that is, a torquer.

Next, to explain using FIG. 6, the light receiving element 21
is connected between power supply terminals 30 and 31 via a resistor _R1 to emit light. The light receiving part 20a of the light receiving element 20,
Each of the light receiving elements 20b photoelectrically converts the light from the light receiving element 21, and the output voltage of each of the light receiving parts 20a and 20b is differentiated by an operational amplifier (hereinafter referred to as an "operational amplifier") 32 that constitutes a differential amplifier together with resistors _R2 and _R3 . The signals are dynamically amplified and compared to generate a detection signal. The light shielding pin 16, the light receiving element 20,
The light receiving element 21 and the operational amplifier 32 constitute a deviation detection device.

The current of this detection signal flows from the torquer coil 25 to the resistor _R4 . The resistor _R4 performs current/voltage conversion, and the detection signal in voltage form is outputted between the terminals 33a and 33b.

Here, when positive acceleration is applied in the direction of arrow A ₁ (or A ₂ ), the light shielding pin 16 is deflected in the direction of arrow B ₁ (or B ₂ ) according to the magnitude of the positive acceleration, and the light receiving part 2
As the amount of light received by 0b (or 20a) increases, a detection signal having a value corresponding to the amount of deviation of the light shielding pin 16 is generated. This deviation detection signal is transmitted to the torquer coil 25.
The light shielding pin 16 is attached to the pendulum 10 by flowing through the pendulum 10.
is driven in the direction of returning to its original state. At the same time, a detection signal having a level corresponding to the deviation, that is, a level corresponding to the acceleration, is detected between the terminals 33a and 33b.

Problems to be Solved by the Invention When measuring acceleration in the direction of gravity using a conventional accelerometer that detects acceleration by the deflection of the pendulum 10, gravitational acceleration is always applied to the pendulum 10. Therefore, in the conventional accelerometer, even when there is no acceleration other than gravitational acceleration, the pendulum is kept in a steady position by the interaction between the magnetic field generated in the torquer coil 25 and the permanent magnets 22 and 23 in the accelerometer. Due to the restraint, it was necessary to continue applying current to the torquer coil 25.

The present invention has been made in view of the above points, and its purpose is to provide an accelerometer that can restrain a pendulum in a steady position without passing current through the torquer coil when there is no acceleration other than gravitational acceleration. shall be.

Means for Solving the Problems The accelerometer of the present invention is provided with a beard whose inner end is fixed to the rotation axis of the pendulum and whose outer end is fixed to the main body of the accelerometer. The structure is such that the torque generated by the pendulum's own weight is canceled out by the repulsive force caused by the deformation of the full swing of the whiskers, thereby restraining the pendulum in a steady position.

Function The torque generated by the pendulum's own weight is canceled by the repulsive force caused by the deformation of the whole whisker, and the pendulum is restrained in a steady position, so the consumption of the current flowing through the torquer coil can be reduced.

Embodiment FIGS. 1A, B, and C show a front view, a side view, and a cross-sectional view of essential parts of a first embodiment of the accelerometer of the present invention, respectively. The same components as in Fig. 5 are given the same reference numerals.
The explanation will be omitted. Further, a circuit similar to the circuit used in the conventional accelerometer shown in FIG. 6 is also used in the accelerometer of this embodiment.

In FIG. 1, in addition to the conventional accelerometer shown in FIG. 5, there is newly provided a mustache full-length 26 whose spring constant is sufficiently small as described below.

As shown in the front view of FIG. 2A and the side view of FIG. As shown in FIG.
In addition, the outer ends 26a are fixed to the frame 13, respectively.

This whole mustache 26 is in a state where there is no acceleration other than gravity, and the light shielding pin 16 is
A torque is applied to the pendulum 10 so that the torque is approximately balanced with the torque generated by the pendulum's own weight.

In a steady state where no acceleration other than gravitational acceleration is applied, by providing the above-mentioned whiskers 26, the torque generated on the pendulum 10 due to the gravitational acceleration and the torque given to the pendulum 10 by the whiskers in opposition to it can be reduced. Since these are balanced, no unnecessary current flows through the torquer coil 25.

FIG. 3 shows a block diagram of the first embodiment of the present invention, where I is the moment of inertia of the pendulum 10, D is the viscous friction coefficient of the pendulum 10, Kh is the spring constant of the full swing of the beard, and the light receiving element 20 and the light receiving element The sensitivity of the deviation detection device consisting of 21 is Kp, the amplification factor of the amplifier circuit consisting of an operational amplifier is KA, the sensitivity of the torquer coil is Kt, the input acceleration to be detected is α, the output current of the above amplifier circuit is i, and the Laplace variable When is s, the transfer function of all the elements of the control system in FIG. 3 is i=KpKA I/(Is ² +Ds+Kh)+KtKpKAα. The steady-state characteristics of this control system can be obtained as follows, by setting s to O: i=KpKA I/Kh+KtKpKAα.

Here, KA of the amplifier circuit consisting of operational amplifier 32
If is sufficiently large and the spring constant Kh of the whole beard is sufficiently small, then i=Kp I/Kh/KA+KtKpα≒I/Ktα (∴Kh/KA≒0) and the output of the amplifier circuit consisting of operational amplifier 32. The current i is proportional to the input acceleration α to be detected. In this embodiment, the spring constant of the full-length hair 26 is set to a sufficiently small value. Therefore, the above condition ((Kh/KA)≒0) actually holds,
The effect of the whisker movement 26 on the accuracy of the measurement can be ignored.

FIG. 4 is a sectional view of a second embodiment of the accelerometer according to the present invention, and the same components as those in FIG. In this embodiment, in addition to the Hige Zenbu 26 of the first embodiment, a second Hige Zenbu 40 is provided, and as shown in the figure, it is placed in a position opposite to the Hige Zenbu 26 with respect to the pendulum 10 due to its deformation. The direction of the force applied to the rotation axis 11 of the repulsive force is configured to be opposite to the direction of the full beard movement 26.

According to this embodiment, two whiskers are 26,40
By providing a
Since the effects of the torques generated at 6 and 40 cancel each other out, fluctuations in measurement accuracy caused by temperature changes can be reduced.

Effects of the invention As described above, according to the invention, when measuring acceleration in the direction of gravity, if there is no acceleration other than gravitational acceleration, the pendulum is restrained in a steady position by the repulsive force caused by the deformation of the whole whisker. By doing so,
There is no need to apply current to the torquer coil to generate a magnetic field, making it possible to significantly reduce current consumption. In addition, since the spring constant of this whole whisker movement is suppressed to a small value, measurement sensitivity does not decrease.

Furthermore, by providing two full-length whiskers so that their repulsive forces are in opposite directions, stable measurement accuracy can be maintained even over a wide range of temperature changes.

[Brief explanation of the drawing]

Figure 1 is a front view, side view, and cross-sectional view of essential parts of the first embodiment of the present invention, Figure 2 is a front view and side view of the full beard, and Figure 3 is a block diagram of an embodiment of the present invention. Figure 4 is a sectional view of the second embodiment of the present invention, Figure 5 is a diagram.
The figures are a front view, a side view, and a cross-sectional view of essential parts of a conventional accelerometer, and FIG. 6 is a circuit diagram of the conventional accelerometer and the accelerometer of the present invention. 10... Pendulum, 11... Rotation axis, 22, 23...
...Permanent magnet, 25...Toruka coil, 26,4
0... full beard dance.

Claims (1)

[Claims for Utility Model Registration] The deflection of a pendulum in response to acceleration is detected by a deflection detection device, and the obtained detection signal is supplied to a torquer coil to drive the pendulum back to its original position. In an accelerometer that expresses acceleration by the value of a detection signal, the inner end thereof is fixed to the rotating shaft of the pendulum, and
When detecting acceleration in the direction of gravity by disposing a beard whose outer end is fixed on the main body of the accelerometer,
An accelerometer configured to maintain the pendulum in a steady position by canceling out the torque generated by the pendulum's own weight by the repulsive force caused by the deformation of the whole whisker.