JP7407617B2 - Acceleration measurement device and acceleration measurement method - Google Patents

Description

The present invention relates to an acceleration measuring device and an acceleration measuring method.

In a charge output type acceleration sensor using a piezoelectric element, the charge sensitivity changes significantly with respect to temperature. Therefore, a certain piezoelectric element is connected to a temperature compensation capacitor to improve its temperature dependence (for example, see Patent Document 1).

Further, in some sensor output circuits, the temperature of a piezoelectric sensor is measured based on a temperature measuring resistor such as a thermistor, and temperature compensation is performed based on the measured temperature (for example, see Patent Document 2).

In this way, even if the charge sensitivity of the acceleration sensor has temperature dependence, if the temperature of the acceleration sensor is specified, it is possible to correct temperature changes in the charge sensitivity and obtain more accurate measurement results.

Japanese Patent Application Publication No. 05-284600 Japanese Patent Application Publication No. 2011-169783

However, in the above technology, in order to specify the temperature of the acceleration sensor, it is necessary to provide a temperature sensor and measure the temperature of the acceleration sensor. The actual temperature of the element itself and the temperature measured by the temperature sensor do not necessarily match, and there is a possibility that temperature compensation of the acceleration sensor will not be performed accurately.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an acceleration measuring device and an acceleration measuring method that accurately compensate for the temperature of an acceleration sensor without incorporating a temperature sensor in the acceleration sensor.

An acceleration measuring device according to the present invention includes a charge output type acceleration sensor and a charge amplifier electrically connected to the charge output type acceleration sensor through a transmission cable. The acceleration measuring device further includes a superimposed signal source that outputs a known superimposed signal, and a switch section that superimposes the superimposed signal on a detection signal of the charge output type acceleration sensor. The charge amplifier includes an amplifier circuit that receives a detection signal via a transmission cable, amplifies the detection signal, and outputs an obtained output signal, and a calculation unit that derives acceleration based on the output signal. Then, the calculation unit controls the switch unit to (a) derive the capacitance of the charge output type acceleration sensor from the output signal obtained with the superimposed signal superimposed on the detection signal, and (b) derive the capacitance of the charge output type acceleration sensor. Acceleration is derived from the output signal while performing temperature compensation based on capacitance.

The acceleration measurement method according to the present invention receives a detection signal from a charge output type acceleration sensor via a transmission cable, outputs an output signal obtained by amplifying the detection signal with a charge amplifier, and outputs an output signal obtained by amplifying the detection signal with a charge amplifier. This is an acceleration measurement method for deriving acceleration; (a) controlling the switch unit to make a known superimposed signal output from the superimposed signal source superimposed on the detection signal of the charge output type acceleration sensor; (b) Deriving the capacitance of the charge output type acceleration sensor from the derived output signal, and (b) deriving the acceleration from the output signal on which the superimposed signal is not superimposed while performing temperature compensation based on the derived capacitance.

According to the present invention, it is possible to obtain an acceleration measuring device and an acceleration measuring method that accurately compensate for the temperature of an acceleration sensor without incorporating a temperature sensor into the acceleration sensor.

FIG. 1 is a diagram showing the configuration of an acceleration measuring device according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the temperature dependence characteristic of charge sensitivity of a charge output type acceleration sensor. FIG. 3 is a diagram illustrating the temperature dependence characteristics of capacitance of a charge output type acceleration sensor. FIG. 4 is a circuit diagram showing the amplifier circuit 21 in the first embodiment. FIG. 5 is a block diagram showing the configuration of the calculation section 22 in FIG. 1. FIG. 6 is a circuit diagram showing the amplifier circuit 21 in the second embodiment.

Embodiments of the present invention will be described below based on the drawings.

Embodiment 1.

FIG. 1 is a diagram showing the configuration of an acceleration measuring device according to an embodiment of the present invention. The acceleration measuring device shown in FIG. 1 includes an acceleration sensor 1, a charge amplifier 2, and a transmission cable 3 (for example, a low noise cable) that electrically connects the acceleration sensor 1 and the charge amplifier 2.

The acceleration sensor 1 is a charge output type acceleration sensor and does not include an amplifier or the like. Although the acceleration sensor 1 shown in FIG. 1 is of a shear type, other types such as a compression type may be used. In FIG. 1, the acceleration sensor 1 includes a piezoelectric element 12 (such as a piezoelectric ceramic) installed on a post 11 and a weight 13 installed on the piezoelectric element 12. As the piezoelectric element 12, for example, a piezoelectric element such as PZT (Pb[Zr·Ti]O ₃ ) is used.

FIG. 2 is a diagram illustrating the temperature dependence characteristic of charge sensitivity of a charge output type acceleration sensor. FIG. 3 is a diagram illustrating the temperature dependence characteristics of capacitance of a charge output type acceleration sensor. In the acceleration sensor 1 using such a piezoelectric element 12, charge sensitivity and capacitance change depending on the temperature, as shown in FIGS. 2 and 3, for example. In addition, FIG. 2 and FIG. 3 show the relative change rate at each temperature based on the value of 20 degrees Celsius.

Further, the charge amplifier 2 is a device that amplifies the detection signal output from the acceleration sensor 1 to generate an output signal and derive a measured value of acceleration. For example, as shown in FIG. 1, the charge amplifier 2 includes an amplifier circuit 21 and a calculation section 22. The amplifier circuit 21 receives the detection signal of the acceleration sensor 1 via the transmission cable 3, amplifies the detection signal, and outputs an output signal obtained. The calculation unit 22 derives acceleration (that is, the acceleration measurement value by the acceleration sensor 1) based on the output signal.

FIG. 4 is a circuit diagram showing the amplifier circuit 21 in the first embodiment. Note that in FIG. 4, the acceleration sensor 1 and the transmission cable 3 are shown as equivalent circuits.

In the first embodiment, for example, as shown in FIG. 4, the charge amplifier 2 further includes a superimposed signal source V2 that outputs a known superimposed signal, and a switch section SW1 that superimposes the superimposed signal on the above-mentioned detection signal. Here, the superimposed signal has an alternating voltage of known frequency. The switch section SW1 is controlled by the calculation section 22 and opens and closes in accordance with the control signal CNT supplied from the calculation section 22.

In the first embodiment, for example, as shown in FIG. 4, the amplifier circuit 21 includes an inverting amplifier circuit, and the inverting amplifier circuit includes an operational amplifier AMP, a feedback resistor R1, a capacitor C3, and one input of the operational amplifier AMP. and an input side resistor R2 connected to the terminal (positive input terminal). The above-described detection signal is input to the other input terminal (negative input terminal) of the operational amplifier AMP. Then, the switch unit SW1 superimposes the superimposed signal on the detection signal by connecting the superimposed signal source V2 to the input resistor R2 in parallel (that is, to the positive input terminal of the operational amplifier AMP).

FIG. 5 is a block diagram showing the configuration of the calculation section 22 in FIG. 1. The calculation section 22 includes a control section 41 , a storage section 42 , an A/D conversion section 43 , a calculation section 44 , and a signal output section 45 .

The control unit 41 switches the operation mode and controls the switch unit SW1 by supplying a control signal CNT to the switch unit SW1. The control unit 41 selects the operation mode from the temperature compensation information measurement mode and the acceleration measurement mode, and controls the open/close state of the switch unit SW1 according to the selected operation mode. In the temperature compensation information measurement mode, the switch part SW1 is closed and temperature compensation information is measured based on the output signal Vout of the amplifier circuit 21. In the acceleration measurement mode, the switch part SW1 is opened and temperature compensation is performed using the measured temperature compensation information. Acceleration is measured.

The storage unit 42 includes a nonvolatile storage device, and stores data necessary for measuring temperature compensation information, temperature compensation, and acceleration measurement in the nonvolatile storage device.

The A/D converter 43 converts the output signal Vout from an analog signal to a digital signal.

The calculation unit 44 derives temperature compensation information from the value of the output signal Vout, and derives an acceleration measurement value from the value of the output signal Vout while performing temperature compensation.

Specifically, in the temperature compensation information measurement mode, the calculation unit 44 calculates the capacitance of the acceleration sensor 1 corresponding to the current temperature T from the output signal Vout obtained when the superimposed signal is superimposed on the detection signal. C1(T) is derived as temperature compensation information.

In addition, in the acceleration measurement mode, the calculation unit 44 performs temperature compensation based on the derived temperature compensation information (that is, the capacitance corresponding to the current temperature T), while making sure that the superimposed signal is not superimposed on the detection signal. The acceleration is derived from the output signal Vout obtained in the state.

Specifically, temperature compensation is performed based on the temperature-dependent characteristic information of the charge sensitivity of the acceleration sensor 1 and the temperature-dependent characteristic information of the capacitance of the acceleration sensor 1. Temperature-dependent characteristic information of charge sensitivity and capacitance is stored in advance in the storage unit 42, and the calculation unit 44 reads and uses the information to derive temperature compensation information.

The above-mentioned temperature dependence characteristic information of charge sensitivity is, for example, a conversion table or a conversion formula, and is a combination of temperature and the charge sensitivity of the acceleration sensor 1 at that temperature (or between the charge sensitivity at that temperature and the charge sensitivity at a reference temperature). (rate of change).

The above-mentioned capacitance temperature dependence characteristic information is, for example, a conversion table or a conversion formula, and is a combination of temperature and capacitance of the acceleration sensor 1 at that temperature (or capacitance at that temperature and capacitance at a reference temperature). (rate of change with capacitance) is shown.

Note that the above-mentioned temperature-dependent characteristic information of charge sensitivity and the above-mentioned temperature-dependent characteristic information of capacitance are specified in advance through experiments or the like.

More specifically, the calculation unit 44 (a) calculates the current value of the acceleration sensor 1 corresponding to the obtained capacitance C1(T) based on the temperature-dependent characteristic information of the capacitance C1(T). (b) identify the charge sensitivity corresponding to the identified temperature T based on the temperature dependence characteristic information of the charge sensitivity; (c) correct the output signal Vout based on the identified charge sensitivity; temperature compensation.

Note that when the temperature-dependent characteristic information of capacitance C1(T) is a discrete conversion table, if there is no value matching the input value (capacitance C1(T) or its rate of change) in the conversion table, The output value (temperature T) corresponding to the value closest to the input value is used, or the value (temperature T) obtained by interpolating multiple output values corresponding to multiple values around the input value is used. Sometimes it happens.

Similarly, when the temperature dependence characteristic information of charge sensitivity is a discrete conversion table, when there is no value that matches the input value (temperature T) in the conversion table, the output value corresponds to the value closest to the input value. (charge sensitivity or its rate of change) is used, or a value (charge sensitivity or its rate of change) obtained by interpolating a plurality of output values corresponding to a plurality of values around the input value is used.

Furthermore, for example, (a) in a state where the superimposed signal is superimposed on the detection signal, the amplitude of the superimposed signal is adjusted so that, at the maximum amplitude of the detection signal, the component resulting from the detection signal in the output signal Vout is less than a predetermined error level. is set to be larger than the maximum amplitude of the detection signal (for example, the amplitude of the superimposed signal is set to 100 times or more the maximum amplitude of the detection signal), and (b) the calculation unit 44 calculates the The capacitance C1(T) of the acceleration sensor 1 may be derived by ignoring the component.

Further, for example, (a) the superimposed signal is a signal of a specific frequency or a specific frequency band different from the possible frequency band of the detection signal, and (b) the calculation unit 44 calculates the frequency component of the detection signal in the output signal Vout. The capacitance C1(T) of the acceleration sensor may be derived by attenuating the output signal Vout by filtering and ignoring the component resulting from the detection signal in the output signal Vout. For example, the frequency of the superimposed signal is set sufficiently higher than the possible frequency band of the detection signal, and the frequency components of the detection signal are attenuated by high-pass filter processing.

Further, the signal output section 45 includes, for example, an interface circuit, and the interface circuit outputs the temperature-compensated acceleration measurement value obtained by the calculation section 44 in a predetermined data format.

For example, the control unit 41, calculation unit 44, etc. in the calculation unit 22 are realized by a computer that executes a predetermined program.

Next, the operation of the acceleration measuring device according to the first embodiment will be explained.

First, the control unit 41 selects the temperature compensation information measurement mode and controls the switch unit SW1 to electrically connect the superimposed signal source V2 to the input terminal of the operational amplifier AMP, so that the known superimposed signal is transmitted to the acceleration sensor 1. The detection signal is superimposed on the detection signal. Then, in the temperature compensation information measurement mode, the calculation unit 44 derives the capacitance C1(T) of the acceleration sensor 1 from the output signal obtained in this state.

Immediately after the capacitance C1(T) is derived, the control unit 41 selects the acceleration measurement mode and controls the switch unit SW1 to electrically disconnect the superimposed signal source V2 from the input terminal of the operational amplifier AMP. In this case, the superimposed signal is not superimposed on the detection signal of the acceleration sensor 1. Then, in the acceleration measurement mode, the calculation unit 44 derives the acceleration from the output signal Vout obtained in this state while performing temperature compensation based on the derived capacitance C1(T).

Here, the derivation of capacitance C1(T) and temperature compensation in the first embodiment will be specifically explained.

Here, V1(T) is the detection voltage of the acceleration sensor 1 at the current temperature T of the acceleration sensor 1, V2 is the voltage of the superimposed signal, and Vout(T) is the current temperature of the acceleration sensor 1. Let C1 (T) be the output voltage of the amplifier circuit 21 when T, C1 (T) be the capacitance of the acceleration sensor 1 at the current temperature T, and C2 be the capacitance (known) of the transmission cable 3. (about 100 pF/m in the case of a general low-noise cable), C3 is the capacitance of the feedback section of the inverting amplifier circuit in the amplifier circuit 21 (generally about 1000 pF), and R1 is the inverting amplifier circuit in the amplifier circuit 21. The resistance value of the feedback resistor (generally about 1GΩ).

In the case of the circuit shown in FIG. 4, the output voltage Vout(T) of the amplifier circuit 21 is expressed as in the following equation.

Vout(T) =-V1(T)×C1(T)/C3+V2×((C1(T)+C2)/C3+1)

Note that the current temperature T of the acceleration sensor 1 is unknown because it is not measured by a separate sensor or the like.

Here, if V2 is made sufficiently large as described above or if filtering is performed by setting the frequency of V2 as described above, the first term of the above equation can be ignored, so the output voltage Vout of the amplifier circuit 21 is expressed as the following equation.

Vout(T) ≒ V2×((C1(T)+C2)/C3+1)

In this case, since the following equation is obtained from this equation, the capacitance C1(T) is derived from the output voltage Vout(T) according to the following equation.

C1(T) = C3×(Vout(T)/V2-C2/C3-1)

On the other hand, in the circuit shown in FIG. 4, the following equation holds true for the output voltage Vout(T).

Vout(T) = V1(T)×C1(T)/C3

Here, if the charge sensitivity of the acceleration sensor 1 at the current temperature T is expressed as the charge output Q1(T) [pC/(m/s ² )], this equation becomes as follows.

Vout(T)＝Q1(T)/C3

Then, the ratio of the charge output Q1(T) corresponding to the capacitance C1(T) and the charge output Q1(Tref) at the reference temperature Tref is calculated based on the temperature-dependent characteristic information of the capacitance C1(T) and the charge Temperature compensation is performed by correcting Vout(T), which is specified based on the temperature-dependent characteristic information of sensitivity, and based on the specified ratio.

For example, as shown in FIGS. 2 and 3, the temperature-dependent characteristic information of capacitance C1(T) and the temperature-dependent characteristic information of charge sensitivity are described as the rate of change in value at each temperature with respect to the reference temperature Tref. If so, first, the ratio between capacitance C1(T) and capacitance C1(Tref) at reference temperature Tref is derived, and the ratio (i.e., rate of change) is specified, and based on the temperature dependence characteristic information of charge sensitivity, the rate of change of charge sensitivity corresponding to the specified temperature T (i.e., at the current temperature T described above) is determined. The ratio of the charge output Q1(T) at the reference temperature Tref to the charge output Q1(Tref) at the reference temperature Tref is specified. Note that the capacitance C1 (Tref) is known.

As described above, according to the first embodiment, the charge amplifier 2 includes the amplifier circuit 21 that receives the detection signal of the acceleration sensor 1 via the transmission cable 3, amplifies the detection signal, and outputs the obtained output signal. , and a calculation unit 22 that derives acceleration based on the output signal. The charge amplifier 2 further includes a superimposed signal source V2 that outputs a known superimposed signal, and a switch section SW1 that superimposes the superimposed signal on the detection signal, and the calculation section 22 controls the switch section SW1, (a ) Deriving the capacitance of the acceleration sensor 1 from the output signal obtained when the superimposed signal is superimposed on the detection signal, and (b) calculating the acceleration from the output signal while performing temperature compensation based on the derived capacitance. Derive.

As a result, acceleration measurement can be performed while accurately compensating the temperature of the acceleration sensor 1 without incorporating a temperature sensor into the acceleration sensor 1.

Embodiment 2.

In the acceleration measuring device according to the second embodiment, the amplifier circuit 21 in the charge amplifier 2 includes an inverting amplifier circuit.

FIG. 6 is a circuit diagram showing the amplifier circuit 21 in the second embodiment. Note that in FIG. 6, the acceleration sensor 1 and the transmission cable 3 are shown as equivalent circuits.

In the second embodiment, for example, as shown in FIG. 6, the charge amplifier 2 includes a superimposed signal source V2 that outputs a known superimposed signal, and a switch section SW2 that superimposes the superimposed signal on the above-mentioned detection signal. Here, like the switch section SW1, the switch section SW2 is controlled by the calculation section 22, and electrically connects the acceleration sensor 1 to the ground point or the superimposed signal source V2 according to the control signal CNT supplied from the calculation section 22. .

In the second embodiment, as shown in FIG. 6, the amplifier circuit 21 includes an inverting amplifier circuit, and the inverting amplifier circuit includes an operational amplifier AMP, a feedback resistor R1, and a capacitor C3. The input terminal (positive input terminal) is grounded, and the above-mentioned detection signal is input to the other input terminal (negative input terminal) of the operational amplifier AMP. Then, the switch unit SW2 connects the superimposed signal source V2 to the acceleration sensor 1 in series, thereby superimposing the superimposed signal on the detection signal.

Next, the operation of the acceleration measuring device according to the second embodiment will be explained.

First, the control unit 41 selects the temperature compensation information measurement mode and controls the switch unit SW2 to connect the superimposed signal source V2 to the acceleration sensor 1 in series, so that the known superimposed signal is output to the acceleration sensor 1. The state is superimposed on the detection signal. Then, in the temperature compensation information measurement mode, the calculation unit 44 derives the capacitance C1(T) of the acceleration sensor 1 from the output signal obtained in this state.

Immediately after the capacitance C1(T) is derived, the control unit 41 selects the acceleration measurement mode and controls the switch unit SW2 to electrically disconnect the superimposed signal source V2 from the acceleration sensor 1. A state is assumed in which the superimposed signal is not superimposed on the detection signal of the acceleration sensor 1. Then, in the acceleration measurement mode, the calculation unit 44 derives the acceleration from the output signal Vout obtained in this state while performing temperature compensation based on the derived capacitance C1(T).

Here, the derivation of capacitance C1(T) and temperature compensation in the second embodiment will be specifically explained.

Here, V1(T) is the detection voltage of the acceleration sensor 1 at the current temperature T of the acceleration sensor 1, V2 is the voltage of the superimposed signal, and Vout(T) is the current temperature of the acceleration sensor 1. Let C1 (T) be the output voltage of the amplifier circuit 21 when T, C1 (T) be the capacitance of the acceleration sensor 1 at the current temperature T, and C2 be the capacitance (known) of the transmission cable 3. , C3 is the capacitance of the feedback section of the inverting amplifier circuit in the amplifier circuit 21, and R1 is the resistance value of the feedback resistor of the inverting amplifier circuit in the amplifier circuit 21.

At this time, the output voltage Vout of the amplifier circuit 21 is expressed as in the following equation.

Vout(T) = ‐V1(T)×C1(T)/C3‐V2×(C1(T)+C2)/C3

Note that the current temperature T of the acceleration sensor 1 is unknown because it is not measured by a separate sensor or the like.

Here, if V2 is made sufficiently large as described above or if filtering is performed by setting the frequency of V2 as described above, the first term of the above equation can be ignored, so the output voltage Vout of the amplifier circuit 21 is expressed as the following equation.

Vout(T) ≒ -V2 × ((C1(T)+C2)/C3)

In this case, the following equation is obtained from this equation, so the capacitance C1(T) is derived according to the following equation.

C1(T) = C3×(Vout(T)/V2)-C2

Then, similarly to the first embodiment, the ratio of the charge output Q1(T) corresponding to the capacitance C1(T) to the charge output Q1(Tref) at the reference temperature Tref is set as follows: Temperature compensation is performed by correcting Vout(T) based on the specified ratio.

Note that the other configurations and operations of the acceleration measuring device according to the second embodiment are the same as those in the first embodiment, so their explanations will be omitted.

As described above, according to the second embodiment, similarly to the first embodiment, acceleration measurement is performed while accurately performing temperature compensation of the acceleration sensor 1 without incorporating a temperature sensor in the acceleration sensor 1.

Note that various changes and modifications to the embodiments described above will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the subject matter and without diminishing its intended advantages. It is intended that such changes and modifications be included within the scope of the claims.

For example, in the first and second embodiments described above, a plurality of pieces of temperature-dependent characteristic information described above are stored in advance in the storage unit 42 corresponding to a plurality of types of acceleration sensors 1, and the information is actually connected via the transmission cable 3. Temperature-dependent characteristic information corresponding to the type of acceleration sensor 1 may be selected and used for the above-described temperature compensation. Note that the type of acceleration sensor 1 is specified, for example, by a user operation.

Furthermore, in the first and second embodiments described above, the user may be able to add or update the above-mentioned temperature dependent characteristic information stored in the storage unit 42. In that case, for example, the control unit 41 uses a predetermined interface to read new temperature-dependent characteristic information from an external storage medium, and stores the new temperature-dependent characteristic information in the storage unit 42. The temperature dependent characteristic information is updated or the new temperature dependent characteristic information is added to the storage unit 42.

Furthermore, in the first and second embodiments described above, the superimposed signal source V2 and/or the switch sections SW1 and SW2 may be arranged outside the charge amplifier 2. For example, in the case of the second embodiment (FIG. 6), the superimposed signal source V2 and the switch section SW2 may be used as a measurement adapter and placed between the acceleration sensor 1 and the charge amplifier 2. In that case, for example, the measurement adapter is built into the transmission cable 3 or connected to the transmission cable 3.

The present invention is applicable, for example, to acceleration measurement using a charge output type acceleration sensor.

1 Acceleration sensor 2 Charge amplifier 3 Transmission cable 21 Amplification circuit 22 Calculation section SW1, SW2 Switch section V2 Superimposed signal source

Claims (6)

An acceleration measuring device comprising a charge output type acceleration sensor and a charge amplifier electrically connected to the charge output type acceleration sensor by a transmission cable,
a superimposed signal source that outputs a known superimposed signal;
further comprising a switch unit that superimposes the superimposed signal on the detection signal of the charge output type acceleration sensor,
The charge amplifier includes an amplifier circuit that receives the detection signal via the transmission cable, amplifies the detection signal, and outputs an obtained output signal, and a calculation unit that derives acceleration based on the output signal,
The calculation unit controls the switch unit, and (a) derives the capacitance of the charge output type acceleration sensor from the output signal obtained when the superimposed signal is superimposed on the detection signal, and ( b) deriving acceleration from the output signal obtained in a state where the superimposed signal is not superimposed on the detection signal while performing temperature compensation based on the derived capacitance;
An acceleration measuring device featuring: The amplifier circuit includes an inverting amplifier circuit,
The inverting amplifier circuit includes an operational amplifier and an input resistor connected to a positive input terminal of the operational amplifier,
The detection signal is input to the negative input terminal of the operational amplifier,
The switch section connects the superimposed signal source to the input resistor in parallel, thereby superimposing the superimposed signal on the detection signal;
The acceleration measuring device according to claim 1, characterized in that: The amplifier circuit includes an inverting amplifier circuit,
The inverting amplifier circuit includes an operational amplifier,
The switch section connects the superimposed signal source to the charge output type acceleration sensor in series, thereby superimposing the superimposed signal on the detection signal;
The acceleration measuring device according to claim 1, characterized in that: The superimposed signal is configured to detect the detection signal such that the component attributable to the detection signal in the output signal is less than a predetermined error level at the maximum amplitude of the detection signal when the superimposition signal is superimposed on the detection signal. has an amplitude greater than the maximum amplitude of the signal;
The calculation unit derives a capacitance of the charge output type acceleration sensor by ignoring a component resulting from the detection signal in the output signal;
The acceleration measuring device according to any one of claims 1 to 3, characterized in that: The superimposed signal is a signal in a frequency band different from the frequency band of the detection signal,
The calculation unit derives the capacitance of the charge output type acceleration sensor by attenuating the frequency component of the detection signal in the output signal by filtering and ignoring the component caused by the detection signal in the output signal. to do,
The acceleration measuring device according to any one of claims 1 to 3, characterized in that: Acceleration measurement in which a detection signal from a charge output type acceleration sensor is received via a transmission cable, a charge amplifier amplifies the detection signal and outputs an obtained output signal, and the charge amplifier derives acceleration based on the output signal. In the method,
controlling the switch unit to bring a known superimposed signal output from the superimposed signal source into a state where it is superimposed on the detection signal of the charge output type acceleration sensor;
Deriving the capacitance of the charge output type acceleration sensor from the output signal obtained in the state,
Deriving acceleration from the output signal on which the superimposed signal is not superimposed while performing temperature compensation based on the derived capacitance;
An acceleration measurement method characterized by:

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