JPH1123611A - Electrostatic torquer type accelerometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an accelerometer for applying a bias voltage to a torquer electrode. SOLUTION: The accelerometer detects an input acceleration through displacement of a pendulum P. A bias voltage is applied to the side of a movable electrode formed on the pendulum P of first and second torquer electrodes A, B and a position detection signal is applied to the fixed electrode side of the first and second torquer electrodes A, B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrostatic torquer accelerometer, and more particularly, to an electrostatic torquer accelerometer for applying a bias voltage to a torquer electrode.

[0002]

2. Description of the Related Art A conventional example of an electrostatic torquer type accelerometer will be described with reference to FIG. In FIG. 2, the capacitance type position detector has two resistors R (R:
And a first position detector electrode α and a second position detector electrode β formed on the pendulum P. The bridge circuit has four sides. The input terminal of the bridge circuit is connected to one terminal of an oscillator OSC having an oscillation frequency on the order of 100 kHz. The fixed electrodes of the two position detector electrodes α and β which are the output terminals of the bridge circuit are connected to a detection circuit U2 composed of a differential amplifier. U3 is a first Toruca electrode drive differential amplifier, and U4 is a second Toruca electrode drive differential amplifier. First Toruca electrode drive differential amplifier U
The non-inverting input 3 is biased by a bias voltage source E that supplies a constant bias voltage, and the inverting input terminal receives the output of the detection circuit U2 and amplifies it. On the other hand, the non-inverting input of the second Toruca electrode driving differential amplifier U4 is biased by a bias voltage source E having a constant voltage, and the output of the detecting circuit U2 is input to the inverting input terminal via the inverter IN. It is a circuit that amplifies.

In the pendulum P, a first torquer electrode A and a second torquer electrode B are formed in addition to the first position detector electrode α and the second position detector electrode β. First
The movable electrode of each of the position detector electrode α and the second position detector electrode β, and the movable electrodes formed on the pendulum P side of the first Toruca electrode A and the second Toruca electrode B are:
All four are electrically connected in common and connected to the other terminal of the oscillator OSC. The fixed electrode of the first Toruca electrode A is connected to the output terminal of the first Toruca electrode drive differential amplifier U3, while the fixed electrode of the second Toruca electrode B is connected to the second Toruca electrode B. The output terminal of the driving differential amplifier U4 is connected.

Here, when the pendulum P is displaced by the application of acceleration, the first position detector electrode α and the second position detector electrode β of the capacitance type position detector are proportional to the amount of displacement of the pendulum P. The output of the polarity corresponding to the direction of the changed displacement is generated. Here, the position detector electrode α and the position detector electrode β generate a larger output when the electrode gap is wider than when the electrode gap is narrower. The detection circuit U2 compares and amplifies the output of these two position detector electrodes and outputs a position detection signal ΔE. This position detection signal △ E
Is the bias voltage source E in the first Toruca electrode drive differential amplifier U3 and the second Toruca electrode drive differential amplifier U4.
, And (+ ΔE + E) is output from the first Toruca electrode drive differential amplifier U3, while the position detection signal ΔE is inverted by the inverter IN to drive the second Toruca electrode drive An inverting input is input to the inverting input terminal of the differential amplifier U4, and the second Toruca electrode driving differential amplifier U4
Outputs (−ΔE + E). The output (E + ΔE) of the first Toruca electrode drive differential amplifier U3 is negatively input to the fixed electrode of the first Toruca electrode A while the output (E−E−) of the second Toruca electrode drive differential amplifier U4. ΔE) is negatively fed back to the fixed electrode of the second Toruca electrode B. here,
A high voltage is applied between the Toruca electrodes having a wide gap, and a low voltage is applied between the Toruca electrodes having a small gap.

[0005]

The above-described electrostatic torquer type accelerometer employs a configuration in which a bias voltage E is superimposed on the position detection signal △ E and this is negatively fed back to the fixed electrode of the torquer electrode. . In order to adopt this configuration, as described above, the first Toruca electrode driving differential amplifier U3 and the second Toruca electrode driving differential amplifier U4 are used as adders for superimposing the bias voltage E on the position detection signal ΔE. And one inverter IN is required to generate a negative feedback signal of both positive and negative polarities. In this case, the maximum value of the negative feedback signal voltage is the maximum value of the potential difference applied between the electrodes, and the range is limited.

The present invention provides an electrostatic torquer type accelerometer that solves the above-mentioned problems.

[0007]

According to the present invention, there is provided an electrostatic torquer type accelerometer for detecting an input acceleration by displacing a pendulum P.
A bias voltage is applied to the movable electrode side formed on the pendulum P side of the Toruca electrode B, and a position detection signal is applied to the fixed electrode side of the first Toruca electrode A and the fixed electrode side of the second Toruca electrode B. An electrostatic Toruca accelerometer was constructed.

Claim 2: In the electrostatic torquer type accelerometer according to claim 1, two resistors R, a first position detector electrode α formed on a pendulum P, and a second position detection. And a first Toruca electrode A and a second Toruca electrode B formed on the pendulum P, and a common connection point of two resistors R and two An oscillator OSC connected between the movable electrode side common connection point formed on the pendulum P of the position detector electrode, and one of the resistor R and the fixed electrode side of the first position detector electrode α common to the fixed electrode side; A detection circuit U2 to which the connection point, the other resistor R, and the common connection point on the fixed electrode side of the second position detector electrode β are connected, wherein both the first torquer electrode A and the second torquer electrode B are connected. The movable electrodes formed on the pendulum P side are An electrostatic torquer type accelerometer which is connected to the positive and negative terminals of the ass voltage source E and whose output terminal is directly connected to the fixed electrode side of the first torquer electrode A and the fixed electrode side of the second torquer electrode B. Was configured.

[0009] Claim 3: Claims 1 and 2
Wherein the bias voltage is applied to the fixed electrode side of the first Toruca electrode A and the fixed electrode side of the second Toruca electrode B, and the position detection signal 1st Toruca electrode A and 2nd Toruca electrode B
An electrostatic torquer accelerometer applied to the movable electrode side formed on the pendulum P side was constructed.

[0010] Claim 4: Claims 1 to 3
In the electrostatic torquer accelerometer described in any one of the above, the bias voltages applied to the first torquer electrode A and the second torquer electrode B have the same absolute value and the opposite polarity. Type accelerometer.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the embodiment shown in FIG. Also in the embodiment of FIG. 1, the capacitance type position detector has two resistances R (R: also indicating the resistance value) having the same resistance value and a first position detection electrode formed on the pendulum P. α, the second position detector electrode β has four sides of a bridge circuit. The input terminal of the bridge circuit is connected to one terminal of an oscillator OSC having an oscillation frequency on the order of 100 kHz. The fixed electrodes of the two position detector electrodes α and β, which are the output terminals of the bridge circuit, are connected to the input terminals of a detection circuit U2 composed of a differential amplifier. The pendulum P has a first position detector electrode α,
In addition to the second position detector electrode β, a first Toruca electrode A and a second Toruca electrode B are formed. The output terminal of the detection circuit U2 is directly connected to the fixed electrode side of the first Toruca electrode A and the fixed electrode side of the second Toruca electrode B.

In this embodiment, the movable electrodes of the first position detector electrode α and the second position detector electrode β are electrically connected in common and connected to the other terminal of the oscillator OSC. doing. Then, the first Toruca electrode A
The movable electrode formed on the pendulum P side of the bias voltage source E is connected to the negative bias voltage terminal -E of the bias voltage source E, while the movable electrode formed on the pendulum P side of the second torquer electrode B is connected to the bias voltage source E. Connected to positive bias voltage terminal + E. That is, a negative bias voltage −E is applied to the movable electrode formed on the pendulum P side of the first Toruca electrode A.
Is applied, a positive bias voltage + E is applied to the movable electrode formed on the pendulum P side of the second Toruca electrode B.

Here, when the pendulum P is displaced by the application of acceleration, the first position detector electrode α and the second position detector electrode β of the capacitance type position detector are proportional to the amount of displacement of the pendulum P. To generate the output. Detection circuit U2
Outputs a position detection signal ΔE having a polarity corresponding to the direction of displacement by comparing and amplifying the input outputs of the two position detector electrodes. This position detection signal △ E is the first Toruca electrode A
And the fixed electrode side of the second Toruca electrode B is directly applied to both. Meanwhile, a negative bias voltage -E is applied to the movable electrode formed on the pendulum P side of the first Toruca electrode A, while the second Toruca electrode B is
A positive bias voltage + E is applied to the movable electrode formed on the side of the pendulum P.

Here, the voltage applied to the first Toruca electrode A is (ΔE−E), and the voltage applied to the second Toruca electrode B is (ΔE + E). Therefore, the range is extended by the applied bias voltage, and the first Toruca electrode drive differential amplifier U3, the second
Electrode drive differential amplifier U4 and inverter IN
Is unnecessary, and the circuit configuration of the electrostatic torquer accelerometer can be simplified accordingly.

[0015]

As described above, according to the present invention, in the electrostatic torquer type accelerometer for detecting the input acceleration by displacing the pendulum, absolute values are applied to the first and second Toruca electrodes. By applying bias voltages having the same value and opposite polarities, the range can be expanded and the circuit configuration of the electrostatic torquer accelerometer can be simplified.

[Brief description of the drawings]

FIG. 1 illustrates an embodiment.

FIG. 2 illustrates a conventional example.

[Explanation of symbols]

 R resistance P pendulum α first position detector electrode β second position detector electrode OSC oscillator U2 detection circuit U3 first Toruca electrode drive differential amplifier U4 second Toruca electrode drive differential amplifier E bias voltage source IN Inverter A First Toruca electrode B Second Toruca electrode

Claims (4)

[Claims] 1. An electrostatic torquer accelerometer for detecting an input acceleration by displacement of a pendulum, wherein a bias voltage is applied to a movable electrode formed on a pendulum side of the first and second Toruca electrodes. An electrostatic torquer accelerometer characterized in that a position detection signal is applied to a fixed electrode side of the first Toruca electrode and a fixed electrode side of the second Toruca electrode. 2. The electrostatic torquer accelerometer according to claim 1, wherein the first position detector electrode and the second position detector electrode formed on the two resistors and the pendulum have four sides. A first Toruca electrode formed in a pendulum and a second
And an oscillator connected between a common connection point of the two resistors and a common connection point on the movable electrode side formed in the pendulum of the two position detector electrodes. A detection circuit for connecting a resistor and a common connection point on the fixed electrode side of the first position detector electrode to another resistance and a common connection point on the fixed electrode side of the second position detector electrode; The movable electrodes formed on the pendulum side of both the Toruca electrode and the second Toruca electrode are separately connected to the positive and negative terminals of the bias voltage source, and the output terminal of the detection circuit is connected to the fixed electrode side of the first Toruca electrode and the second terminal. An electrostatic Toruca-type accelerometer, which is directly connected to the fixed electrode side of the Toruca electrode. 3. An electrostatic torquer accelerometer according to claim 1, wherein the bias voltage is a fixed electrode side of the first Toruca electrode and a fixed electrode of the second Toruca electrode. Wherein the position detection signal is applied to a movable electrode formed on the pendulum side of the first Toruca electrode and the second Toruca electrode. 4. An electrostatic torquer accelerometer according to claim 1, wherein the bias voltage applied to the first and second Toruca electrodes has an absolute value of: An electrostatic torquer accelerometer having the same polarity but opposite to each other.