JP2009020057A - Vibration detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration detector capable of appropriately detecting a plurality of objects to be measured at the same position. <P>SOLUTION: When control by a servo amplifier 21 is switched to ON by a switching part 24, acceleration of a coil bobbin 3 is measured based on detection of a current value flowing to a force coil 2b by a current value detection part 22. In addition, when the control by the serve amplifier 21 is switched to OFF by the switching part 24, induced electromotive force induced on a magneto coil 4 is detected by an induced electromotive force detection part 23, and speed of the coil bobbin 3 is measured based on the induced electromotive force which has been detected. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vibration detector.

  Conventionally, as a detector for measuring vibration and earthquake, a displacement meter, a speedometer, an accelerometer, or the like is used according to a measurement object (displacement, speed, acceleration, etc.).

In particular, seismometers mainly use an electrodynamic speedometer (see Patent Document 1) or a servo-type accelerometer (see Patent Document 2) composed of a coil and a magnet.
JP 2003-42833 A JP 2005-10145 A

However, when there are a plurality of measurement objects such as speed and acceleration, the vibration detector requires dedicated spaces for the speedometer described in Patent Document 1 and the accelerometer described in Patent Document 2, for example. A difference (distance) occurs, and strictly speaking, speed and acceleration cannot be measured at the same position. In particular, in the case of a seismometer, it is necessary to attach detectors for three directions (NS, EW, UD), and it is impossible to accurately measure a plurality of measurement objects at the same position.
In addition, by calculating the velocity by integrating from the acceleration measured by the accelerometer described in Patent Document 2, it is possible to measure a plurality of measurement objects at the same position and the same time. There is a problem that an accumulated error occurs and an accurate speed cannot be measured.

  An object of the present invention is to provide a vibration detector that can suitably detect a plurality of measurement objects at the same position.

In order to solve the above problems, the invention described in claim 1
A pendulum supported in a reciprocating manner by a support spring in the main body case;
A displacement detection unit that detects displacement from a neutral position of the pendulum by an amount of change in capacitance between a fixed electrode provided in the main body case and a movable electrode provided in the pendulum;
A drive control unit configured to cause a current to flow through a force coil that moves the pendulum based on the capacitance change amount detected by the displacement detection unit and to return the pendulum to the neutral position;
Current value detection means for detecting a current value passed through the force coil;
A power generation coil wound around the pendulum;
Induced electromotive force detection means for detecting induced electromotive force induced in the power generation coil;
Switching means for performing ON / OFF switching of the drive control unit;
With
When the control by the drive control unit is switched ON by the switching unit, the current value flowing through the force coil is detected by the current value detection unit, and the control by the drive control unit is turned OFF by the switching unit. In the case of switching to, the induced electromotive force induced in the power generation coil is detected by the induced electromotive force detection means.

The invention described in claim 2
The vibration detector according to claim 1.
The switching means performs ON / OFF switching of the drive control unit every predetermined time.

According to the first aspect of the present invention, when the control by the drive control unit is switched to ON by the switching means, the acceleration of the pendulum is detected based on detecting the current value passed through the force coil by the current value detecting means. When the control by the drive control unit is switched to OFF by the switching means, the induced electromotive force induced in the power generation coil is detected by the induced electromotive force detection means, and the detected induction The pendulum speed can be measured based on the electromotive force.
Therefore, by switching ON / OFF of the drive control unit, the acceleration and speed of the pendulum can be measured with one vibration detector, and a plurality of measurement objects at the same position can be suitably detected. In addition, by simplifying the mechanism of the vibration detector, it is possible to save space and reduce costs.

According to the invention described in claim 2, it is needless to say that the same effect as that of the invention described in claim 1 can be obtained, and the drive control unit is switched ON / OFF at every predetermined time by the switching means. Can do.
Therefore, a plurality of measurement objects can be more suitably detected at the same position every predetermined time.
In particular, by performing high-speed switching at a high frequency, it is possible to perform measurement as if a plurality of measurement objects were measured at the same position and at the same time.

  Hereinafter, the best mode of a vibration detector according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating a main configuration of the vibration detector 100.

  As shown in FIG. 1, the vibration detector 100 includes a vibration detection unit 10 and a control unit 20. The vibration detection unit 10 includes a main body case 1, a drive unit 2, a coil bobbin 3 as a pendulum that is displaced by disturbance vibration, a power generation coil 4 wound around the coil bobbin 3, and a displacement detection unit that detects vibration of the coil bobbin 3. The control unit 20 includes a servo amplifier 21 that controls the drive unit 2, a current value detection unit 22, an induced electromotive force detection unit 23, a switching unit 24, and the like.

  The drive unit 2 includes a magnet (permanent magnet) 2a fixed to the main body case 1, a force coil 2b wound around the coil bobbin 3, and a test coil for testing whether the drive unit 2 is normally driven. 2c. As shown in FIG. 1, the drive unit 2 is configured such that a coil bobbin 3 around which a force coil 2b is wound is inserted into a concave portion of a magnet 2a, and the coil bobbin 3 is made to flow by passing a current through the force coil 2b. Generate electromagnetic force to move.

The coil bobbin 3 is supported in a vertically movable manner in FIG. 1 by a support spring 3 a having one end fixed to the main body case 1.
The support spring 3a is constituted by a diaphragm, for example.

  The power generating coil 4 is wound around the coil bobbin 3 in parallel with the force coil 2b and the test coil 2c.

  The displacement detector 5 includes a movable electrode plate 5a attached to the upper end of the coil bobbin 3 functioning as a capacitor, and a fixed electrode plate 5b disposed on the upper surface of the movable electrode plate 5a and provided on the main body case 1, The displacement of the coil bobbin 3 is detected by measuring the amount of change in the capacitance between the movable plate 5a and the fixed plate 5b, and the detected displacement signal is output to the servo amplifier 21.

For example, as shown in FIG. 2, the servo amplifier 21 includes an amplifier 21 a that amplifies a displacement signal detected by the displacement detector 5, a feedback control circuit 21 b, and the like. Based on the displacement signal output from the displacement detector 5, the servo amplifier 21 controls the amount of current output to the force coil 2 b in order to align the drive unit 2 and the displacement detector 5.
In the above-described configuration, when vibration is applied to the coil bobbin 3 and the coil bobbin 3 deviates from the neutral position, which is the zero position of the measurement point, the displacement detector 5 detects this deviation amount, and the servo amplifier 21 receives the signal to It operates so that a current flows through the force coil 2b of the drive unit 2.
Thereby, the servo amplifier 21 functions as a drive control unit.

The current value detection unit 22 detects the current flowing through the force coil 2b.
This current generates a force (electromagnetic force) in the opposite direction to the displacement of the coil bobbin 3, and acts to return the coil bobbin 3 to the neutral position. Since this electromagnetic force is in balance with the acceleration that causes the coil bobbin 3 to shift, the acceleration applied to the coil bobbin 3 can be detected by measuring this current value.
Thereby, the current value detector 22 functions as a current value detector.

The induced electromotive force detection unit 23 includes, for example, a voltage amplifier 23a, a voltage detection circuit 23b, an attenuation circuit 23c for suppressing vibration given to the coil bobbin 3, and the like as shown in FIG. An induced electromotive force induced in the power generation coil 4 is detected via an output terminal (not shown) connected to the coil 4. Thereby, the induced electromotive force induced in the power generation coil 4 can be measured.
Thereby, the induced electromotive force detection part 23 functions as an induced electromotive force detection means.

  In the above configuration, when vibration is applied to the coil bobbin 3, the coil bobbin 3 is elastically displaced in the vertical direction in FIG. Then, the power generation coil 4 wound around the coil bobbin 3 is displaced in a direction substantially perpendicular to the direction of the magnetic field lines of the magnetic field. Thereby, Lorentz force according to the speed of the coil bobbin 3 acts on the electric charge in the conducting wire constituting the power generating coil 4. Therefore, an induced electromotive force corresponding to the movement of the coil bobbin 3 is generated in the power generation coil 4. The induced electromotive force induced in the power generation coil 4 is expressed by the following equation (1).

E = B × L × V × sinθ (1)
In Expression (1), E represents an induced electromotive force induced in the power generation coil 4, B represents a magnetic flux density of a magnetic field generated by the magnet 2a, and L represents a length of a conductive wire constituting the power generation coil 4, that is, a coil. V represents the relative speed between the power generating coil 4 and the magnet 2a, and θ represents the angle between the direction in which the power generating coil 4 is relatively displaced and the direction of the magnetic field lines of the magnetic field generated by the magnet 2a. Since the magnet 2a is fixed and the power generation coil 4 is displaced, the relative speed V is equivalent to the displacement speed of the power generation coil 4. For this reason, the speed applied to the coil bobbin 3 can be detected.

The switching unit 24 performs ON / OFF switching of control for outputting current to the force coil 2b by the servo amplifier 21.
Specifically, as shown in FIG. 2, when the switch SW1 and the switch SW2 that are the switching unit 24 are in the “ON” state, the servo amplifier 21 performs control to output current to the force coil 2b, and the switch SW1 and When the switch SW2 is in the “OFF” state, the servo amplifier 21 does not output the current to the force coil 2b, detects the induced electromotive force induced in the power generating coil 4, and detects the detected induced electromotive force. Control for measuring the speed of the coil bobbin 3 is performed based on the above.
Further, the switch SW1 and the switch SW2 are configured to perform ON / OFF switching every predetermined time, and perform high-speed switching at a high frequency (for example, 3 kHz).
Thereby, the switching unit 24 functions as a switching unit.

  Next, a method for detecting acceleration and velocity by the vibration detector 100 will be described with reference to FIG. FIG. 2 is a block diagram showing an operation mechanism of the feedback control system.

  As shown in FIG. 2, when vibration is applied to the coil bobbin 3 in the state where the switch SW1 and the switch SW2 of the switching unit 24 are “OFF”, the coil bobbin 3 is elastically displaced and the power generation wound around the coil bobbin 3 is performed. The coil 4 vibrates in a direction substantially perpendicular to the direction of the magnetic field lines of the magnetic field. Thereby, Lorentz force according to the speed of the coil bobbin 3 acts on the electric charge in the conducting wire constituting the power generation coil 4, and an induced electromotive force according to the movement of the coil bobbin 3 is generated in the power generation coil 4. At this time, the induced electromotive force generated by the power generation coil 4 is amplified by the voltage amplifier 23a, and the speed is detected by measuring the induced electromotive force by the voltage detection circuit 23b.

  On the other hand, when the switch SW1 and the switch SW2 of the switching unit 24 are in the “ON” state, when vibration is applied to the coil bobbin 3, the coil bobbin 3 is elastically displaced, and the movable pole plate 5a provided on the coil bobbin 3 is displaced. . Thereby, the displacement detector 5 detects a change in capacitance between the movable plate 5a and the fixed plate 5b in accordance with the displacement, converts the change in capacitance into a voltage, and servos it as a displacement signal. Output to the amplifier 21. Then, the feedback control circuit 21b in the servo amplifier 21 generates a feedback signal and outputs the feedback signal to the drive control unit. The drive control unit supplies current corresponding to the feedback signal to the force coil 2b of the drive unit 2 and performs control to return the coil bobbin 3 to the neutral position. At this time, the acceleration is detected by measuring the value of the current supplied to the force coil 2 b by the current value detection unit 22.

According to the vibration detector 100 according to the present invention, when the control by the servo amplifier 21 is switched to ON by the switching unit 24, the current value flowing through the force coil 2b is detected by the current value detection unit 22. The acceleration of the coil bobbin 3 can be measured based on this, and when the control by the servo amplifier 21 is switched to OFF by the switching unit 24, the induced electromotive force induced in the power generating coil 4 by the induced electromotive force detection unit 23 The speed of the coil bobbin 3 can be measured based on the detected induced electromotive force.
Therefore, by switching ON / OFF of the servo amplifier 21, it is possible to measure the acceleration and speed of the coil bobbin 3 with one vibration detector 100, and to suitably detect a plurality of measurement objects at the same position. Can do.
In addition, by simplifying the mechanism of the vibration detector 100, it is possible to save space and reduce costs.
Furthermore, the switching unit 24 can perform ON / OFF switching of the servo amplifier 21 every predetermined time.
Therefore, a plurality of measurement objects can be more suitably detected at the same position every predetermined time.
In particular, by performing high-speed switching at a high frequency (for example, 3 kHz), it is possible to perform measurement as if a plurality of measurement objects were measured at the same position and the same time.

  The present invention is not limited to the above embodiment. For example, the switching unit 24 may be designed so that the timing for switching the switch SW1 and the switch SW2 can be set to a user-desired timing. In addition, the present invention can be freely changed and improved without departing from the gist of the invention.

It is a figure which shows the principal part structure of the vibration detector which concerns on this invention. It is a block diagram which shows the operation mechanism of the feedback control system of the vibration detector which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Vibration detector 10 Vibration detection part 1 Main body case 2 Drive part 2a Magnet 2b Force coil 3 Coil bobbin (pendulum)
3a Support spring 4 Power generation coil 5 Displacement detection unit 20 Control unit 21 Servo amplifier (drive control unit)
22 Current value detection unit (current value detection means)
23 Inductive electromotive force detection unit (inductive electromotive force detection means)
24 switching part (switching means)

Claims (2)

A pendulum supported in a reciprocating manner by a support spring in the main body case;
A displacement detection unit that detects displacement from a neutral position of the pendulum by an amount of change in capacitance between a fixed electrode provided in the main body case and a movable electrode provided in the pendulum;
A drive control unit configured to cause a current to flow through a force coil that moves the pendulum based on the capacitance change amount detected by the displacement detection unit and to return the pendulum to the neutral position;
Current value detection means for detecting a current value passed through the force coil;
A power generation coil wound around the pendulum;
Induced electromotive force detection means for detecting induced electromotive force induced in the power generation coil;
Switching means for performing ON / OFF switching of the drive control unit;
With
When the control by the drive control unit is switched ON by the switching unit, the current value flowing through the force coil is detected by the current value detection unit, and the control by the drive control unit is turned OFF by the switching unit. In the vibration detector, the induced electromotive force induced in the power generation coil is detected by the induced electromotive force detection means.   The vibration detector according to claim 1, wherein the switching unit performs ON / OFF switching of the drive control unit every predetermined time.

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