阅读说明：本技术 信号处理装置、惯性传感器、信号处理方法和程序 (Signal processing device, inertial sensor, signal processing method, and program ) 是由 黑田启介 梶原拓也 中塚淳二 永井正昭 于 2020-01-09 设计创作，主要内容包括：本文公开了一种用于在抑制灵敏度降低的同时减小他轴灵敏度的影响的技术。一种信号处理装置(1)包括检测电路(11)和校正电路(12)。检测电路(11)包括第一检测单元(112)和第二检测单元(113)。第一检测单元(112)基于对应于至少两个方向中每一个方向的相关输出信号(Sig1)产生至少一个检测信号(Sig2)。第二检测单元(113)具有比第一检测单元(112)更宽的检测范围,并且基于对应于至少两个方向中每一个方向的相关输出信号(Sig1)产生至少一个校正信号(Sig3)。校正电路(12)利用对应于至少两个方向中进行校正的一个方向之外的至少一个方向的相关校正信号,校正对应于至少两个方向中每一个方向的相关检测信号(Sig2)。(Disclosed herein is a technique for reducing the influence of the sensitivity of the other axis while suppressing a decrease in sensitivity. A signal processing apparatus (1) includes a detection circuit (11) and a correction circuit (12). The detection circuit (11) includes a first detection unit (112) and a second detection unit (113). The first detection unit (112) generates at least one detection signal (Sig2) based on the correlation output signal (Sig1) corresponding to each of the at least two directions. The second detection unit (113) has a wider detection range than the first detection unit (112) and generates at least one correction signal (Sig3) based on the correlation output signal (Sig1) corresponding to each of the at least two directions. A correction circuit (12) corrects a correlation detection signal (Sig2) corresponding to each of the at least two directions using correlation correction signals corresponding to at least one direction other than the one direction in which the correction is made.)

1. A signal processing apparatus comprising:

a detection circuit configured to generate a detection signal based on an output signal of at least one detection element configured to detect inertial forces in at least two directions of three directions perpendicular to each other; and

a correction circuit configured to correct the detection signal,

the detection circuit includes:

a first detection unit configured to generate at least one of the detection signals based on a correlation output signal corresponding to each of the at least two directions among the output signals; and

a second detection unit having a wider detection range than the first detection unit and configured to generate at least one correction signal based on a correlation output signal corresponding to each of the at least two directions among the output signals;

the correction circuit is configured to correct a correlation detection signal corresponding to each of the at least two directions in the detection signal using a correlation correction signal corresponding to at least one direction other than the one direction in which the correction is performed in the at least two directions in the correction signal.

2. The signal processing apparatus of claim 1, wherein

Each of the first and second detection units includes an a/D converter.

3. A signal processing apparatus according to claim 1 or 2, wherein

The at least two directions are mutually perpendicular X-axis direction, Y-axis direction and Z-axis direction, and

the at least one detection element comprises:

an X-axis detection element configured to detect an inertial force in an X-axis direction;

a Y-axis detection element configured to detect an inertial force in a Y-axis direction;

a Z-axis detection element configured to detect an inertial force in a Z-axis direction.

4. The signal processing apparatus of any one of claims 1 to 3, wherein

The at least two directions are mutually perpendicular X-axis direction, Y-axis direction and Z-axis direction,

the detection circuit includes:

an X-axis detecting circuit configured to generate a correlation detection signal based on a correlation output signal provided from an X-axis detecting element as the at least one detecting element, the X-axis detecting element being configured to detect an inertial force in an X-axis direction;

a Y-axis detection circuit configured to generate a correlation detection signal based on a correlation output signal provided from a Y-axis detection element as the at least one detection element, the Y-axis detection element being configured to detect an inertial force in a Y-axis direction; and

a Z-axis detection circuit configured to generate a correlation detection signal based on a correlation output signal provided from a Z-axis detection element as the at least one detection element, the Z-axis detection element being configured to detect an inertial force in a Z-axis direction,

the X-axis detection circuit includes an X-axis first detection unit as the first detection unit and an X-axis second detection unit as the second detection unit,

the Y-axis detection circuit includes a first Y-axis detection unit as the first detection unit and a second Y-axis detection unit as the second detection unit, and

the Z-axis detection circuit includes a Z-axis first detection unit as the first detection unit and a Z-axis second detection unit as the second detection unit.

5. The signal processing apparatus according to any one of claims 1 to 4, further comprising a signal comparison unit configured to compare each detection signal supplied from the first detection unit with the correlation correction signal supplied from the second detection unit.

6. An inertial sensor, comprising:

the signal processing apparatus according to any one of claims 1 to 5; and

the at least one detection element.

7. A signal processing method for processing an output signal of at least one detection element configured to detect inertial forces in at least two of three directions perpendicular to each other, the method comprising:

a first detection step including generating a detection signal based on the output signals corresponding to the at least two directions;

a second detection step including generating a correction signal based on the output signals corresponding to the at least two directions within a detection range wider than the first detection step; and

the step of correcting comprises correcting said detection signal,

the correcting step includes correcting the correlation detection signal corresponding to each of the at least two directions in the detection signal using a correlation correction signal corresponding to at least one direction other than the one direction in which the correction is performed in the at least two directions in the correction signal.

8. A program designed to cause one or more processors to execute the signal processing method according to claim 7.

Technical Field

The present disclosure generally relates to a signal processing apparatus, an inertial sensor, a signal processing method, and a program. More particularly, the present disclosure relates to a signal processing device, an inertial sensor, a signal processing method, and a program that process a signal supplied from a detection element for detecting an inertial force.

Background

Patent document 1 describes an acceleration sensor (inertial sensor) used in, for example, a vehicle, a navigation device, and a mobile telecommunication apparatus. The acceleration sensor of patent document 1 includes a sensor unit (detection element) and a detection circuit (signal processing device). The detection circuit includes a CV converter circuit, a signal conditioner circuit, and an a/D converter circuit (a first detection unit and a second detection unit). The CV converter circuit converts a change in capacitance caused by the sensor cell into a voltage. The signal conditioner circuit samples an output voltage of the CV converter circuit, and amplifies the output voltage to a predetermined sensitivity after adding an offset voltage to the sampled output voltage. The A/D converter circuit converts the output voltage of the signal conditioner circuit to a digital value and provides a digitized output voltage.

If the acceleration sensor of patent document 1 is a three-axis acceleration sensor, for example, the acceleration in the X-axis direction may be affected by at least one of the acceleration in the Y-axis direction and the acceleration in the Z-axis direction. In this case, although it is necessary to reduce the influence of the acceleration, the acceleration having a magnitude exceeding the dynamic range of the AD converter circuit may not be sufficiently reduced.

To overcome this problem, a method of increasing the dynamic range of the a/D converter circuit may be employed. However, this causes a problem that the minimum resolution decreases as the dynamic range increases because there is a trade-off relationship between the dynamic range and the minimum resolution.

Reference list

Patent document

Patent document 1: WO 2015/052926A 1

Disclosure of Invention

Therefore, an object of the present disclosure is to provide a signal processing device, an inertial sensor, a signal processing method, and a program, each configured or designed to reduce the influence of the sensitivity of the other axis while suppressing a decrease in sensitivity.

A signal processing apparatus according to an aspect of the present disclosure includes a detection circuit and a correction circuit. The detection circuit generates a detection signal based on an output signal of at least one detection element that detects inertial forces in at least two directions of three directions perpendicular to each other. The correction circuit corrects the detection signal. The detection circuit includes a first detection unit and a second detection unit. The first detection unit generates at least one detection signal based on the correlation output signal corresponding to each of the at least two directions. The second detection unit has a wider detection range than the first detection unit and is configured to generate at least one correction signal based on the correlation output signal corresponding to each of the at least two directions. The correction circuit corrects the correlation detection signal corresponding to each of the at least two directions using the correlation correction signal corresponding to at least one direction other than the one direction in which the correction is performed.

An inertial sensor according to another aspect of the present disclosure includes the above-described signal processing device and at least one detection element.

A signal processing method according to still another aspect of the present disclosure is a signal processing method for processing an output signal of at least one detection element that detects inertial forces in at least two directions of three directions perpendicular to each other. The signal processing method comprises a first detection step, a second detection step and a correction step. The first detecting step includes generating a detection signal based on the output signals corresponding to the at least two directions. The second detecting step includes generating a correction signal based on the output signals corresponding to the at least two directions within a wider detection range than the first detecting step. The correcting step includes correcting the detection signal. The correcting step includes correcting the correlation detection signal corresponding to each of the at least two directions using the correlation correction signal corresponding to at least one direction other than the one of the at least two directions for which correction is performed.

A program according to still another aspect of the present disclosure is designed to cause one or more processors to execute the above-described signal processing method.

Drawings

Fig. 1 is a schematic diagram showing a configuration of a signal processing apparatus and an inertial sensor according to an example embodiment of the present disclosure;

FIG. 2A illustrates the concept of other axis sensitivity of an inertial sensor;

FIG. 2B illustrates the concept of other axis sensitivity of an inertial sensor;

fig. 3 is an exploded perspective view of a detection element as a constituent element of the inertial sensor;

FIG. 4 is a cross-sectional view taken along the plane X1-X2 shown in FIG. 3;

fig. 5 is a sequence diagram showing how the signal processing apparatus operates; and

fig. 6 is a schematic diagram showing a partial configuration of a signal processing apparatus according to a modification of the present disclosure.

Detailed Description

(examples)

Fig. 3 and 4 referred to in the following description of the embodiment and its variants are both schematic representations. Therefore, the ratio of the sizes (including thicknesses) of the respective constituent elements shown in the drawings does not always reflect their actual size ratio.

(1) Summary of the invention

An outline of the inertial sensor 10 according to this embodiment will be described with reference to fig. 1 and 2.

The inertial sensor 10 according to the present embodiment is a sensor for detecting an inertial force, and may be, for example, a three-axis acceleration sensor that detects acceleration in three axial directions perpendicular to each other. Specifically, the inertial sensor 10 according to the present embodiment can detect the acceleration in the X-axis direction, the acceleration in the Y-axis direction, and the acceleration in the Z-axis direction. As shown in fig. 2A and 2B, the inertial sensor 10 may be, for example, a surface-mounted acceleration sensor mounted on one surface (reference surface) 101 of the printed wiring board 100. The inertial sensor 10 may be implemented as, for example, a capacitive acceleration sensor (see fig. 4).

As shown in fig. 1, an inertial sensor 10 according to the present embodiment includes a signal processing device 1 and a plurality of (three in the example shown in fig. 1) detection elements 2. The signal processing apparatus 1 may be, for example, an ASIC (application specific integrated circuit). In addition, in the present embodiment, the detecting element 2 includes an X-axis detecting element 2A, Y, an axis detecting element 2B, and a Z-axis detecting element 2C. The X-axis detection element 2A detects an inertial force (acceleration) in the X-axis direction. The Y-axis detector 2B detects an inertial force (acceleration) in the Y-axis direction. The Z-axis detecting element 2C detects an inertial force (acceleration) in the Z-axis direction. In the following description, when it is not particularly necessary to distinguish between the X-axis detecting element 2A, Y and the Z-axis detecting element 2B, the X-axis detecting element 2A, Y and the Z-axis detecting element 2C are hereinafter collectively or individually referred to as "detecting elements 2".

Fig. 2A and 2B are schematic diagrams showing a state in which the inertial sensor 10 according to the present embodiment is mounted on the printed wiring board 100. In fig. 2A and 2B, one surface (upper surface) 101 of the printed wiring board 100 is used as a reference surface (hereinafter referred to as "reference surface 101"). Fig. 2A shows the sensitivity of the inertial sensor 10 in the case where the inclination angle with respect to the reference plane 101 is 0 degree. Fig. 2B shows the other-axis sensitivity in the case where the inclination angle of the inertial sensor 10 with respect to the reference plane 101 is θ (θ > 0) degrees. As used herein, "other-axis sensitivity" refers to the degree to which the sensor output in the direction aligned with the measurement axis is affected by acceleration applied in a direction other than the direction aligned with the measurement axis (i.e., acceleration applied in an axial direction perpendicular to the measurement axis). For example, as shown in fig. 2A and 2B, in the case where the gravitational acceleration 1G is applied in the vertical direction (Z-axis direction), the other-axis sensitivity refers to a case where a component of the gravitational acceleration 1G applied in the vertical direction (Z-axis direction) is detected in an axial direction other than the Z-axis direction (for example, the X-axis direction in fig. 2A and 2B).

In fig. 2A, the gravitational acceleration 1G applied in the vertical direction acts only in the Z-axis direction, and does not act in the X-axis direction. That is, in fig. 2A, the sensor output in the X-axis direction is zero, and the sensor output in the Z-axis direction is 1G. In this case, the other-axis sensitivity in the X-axis direction caused by the gravitational acceleration 1G applied in the vertical direction is zero. On the other hand, in fig. 2B, the inertial sensor 10 is inclined with respect to the reference plane 101 of the printed wiring board 100. Therefore, the gravitational acceleration 1G applied in the vertical direction is decomposed into a component in which the gravitational acceleration 1G is applied in the Z-axis direction and a component in which the gravitational acceleration 1G is applied in the X-axis direction. In the example shown in fig. 2B, the inclination angle of the inertial sensor 10 with respect to the reference plane 101 is θ degrees. Therefore, the Z-axis component of the gravitational acceleration 1G is given by (1G × cos θ), and the X-axis component of the gravitational acceleration 1G is given by (1G × sin θ). In this case, the other-axis sensitivity in the X-axis direction caused by the gravitational acceleration 1G applied in the vertical direction is (1G × sin θ). This other-axis sensitivity needs to be reduced by correction because it is an error component in the X-axis direction.

Various methods for correcting such error components caused by the other-axis sensitivity have been provided in the related art. However, for example, the acceleration sensor of patent document 1 described above may not be able to correct an error caused by the other-axis sensitivity in a case where the magnitude of the acceleration causing the other-axis sensitivity is larger than the dynamic range (full-scale voltage) of the a/D converter circuit. In this case, the dynamic range of the a/D converter circuit can be increased to overcome the above-described problem. However, this leads to a problem that the minimum resolution (signal accuracy) decreases with an increase in the dynamic range because there is a trade-off relationship between the dynamic range and the minimum resolution of the a/D converter circuit. The signal processing apparatus 1 according to the present embodiment employs the following configuration to reduce the influence of the other-axis sensitivity while suppressing a decrease in sensitivity (minimum resolution).

As shown in fig. 1, the signal processing apparatus 1 according to the present embodiment includes a detection circuit 11 and a correction circuit 12. The detection circuit 11 generates a detection signal Sig2 based on the output signal Sig1 of at least one detection element 2 that detects inertial forces in at least two of three directions perpendicular to each other. The correction circuit 12 corrects the detection signal Sig 2. The detection circuit 11 includes a first detection unit 112 and a second detection unit 113. The first detection unit 112 generates at least one detection signal Sig2 based on the correlated output signal Sig1 corresponding to each of the at least two directions. The second detection unit 113 has a wider detection range than the first detection unit 112 and generates at least one correction signal Sig3 based on the correlation output signal Sig1 corresponding to each of the at least two directions. The correction circuit 12 corrects the correlation detection signal Sig2 corresponding to each of the at least two directions using the correlation correction signal Sig3 corresponding to at least one direction other than the one direction in which the correction is performed.

As described above, in the signal processing device 1 according to the present embodiment, the detection range (full-scale range) of the second detection unit 113 that generates the correction signal Sig3 is wider than the detection range (full-scale range) of the first detection unit 112 that generates the detection signal Sig 2. Therefore, with respect to the acceleration, the decrease in sensitivity can be suppressed by the first detection unit 112 having a narrower detection range than the second detection unit 113 detecting the acceleration. Meanwhile, with respect to the other-axis sensitivity, even if the magnitude of the acceleration causing the other-axis sensitivity is significant, the influence of the other-axis sensitivity can be reduced by detecting the other-axis sensitivity by the second detection unit 113 having a wider detection range than the first detection unit 112. In short, the signal processing apparatus 1 according to the present embodiment can reduce the influence of the sensitivity of the other axis while suppressing the decrease in sensitivity (minimum resolution).

(2) Configuration of

Next, the configuration of the inertial sensor 10 according to the present embodiment will be described with reference to fig. 1, 3, and 4.

As shown in fig. 1, an inertial sensor 10 according to the present embodiment includes a signal processing device 1 and a plurality of (for example, three in the example shown in fig. 1) detection elements 2.

(2.1) Signal processing device

The signal processing apparatus 1 includes a plurality of (e.g., three in the example shown in fig. 1) detection circuits 11 and a plurality of (e.g., three in the example shown in fig. 1) correction circuits 12.

Each of the plurality of detection circuits 11 is a detection circuit selected from the X-axis detection circuit 11A, Y and the Z-axis detection circuit 11C. The X-axis detection circuit 11A generates a detection signal Sig2 based on an output signal Sig1 of an X-axis detection element 2A to be described later. The Y-axis detection circuit 11B generates a detection signal Sig2 based on an output signal Sig1 of the Y-axis detection element 2B to be described later. The Z-axis detection circuit 11C generates a detection signal Sig2 based on an output signal Sig1 of a Z-axis detection element 2C to be described later.

In addition, each of the plurality of correction circuits 12 is a correction circuit selected from the X-axis correction circuit 11A, Y-axis correction circuit 12B and the Z-axis correction circuit 11C. The X-axis correction circuit 12A corrects an error caused by the other-axis sensitivity in the X-axis direction. The Y-axis correction circuit 12B corrects an error caused by the other-axis sensitivity in the Y-axis direction. The Z-axis correction circuit 12C corrects an error caused by the other-axis sensitivity in the Z-axis direction.

In the following description, when there is no particular need to distinguish the X-axis detection circuit 11A, Y and the Z-axis detection circuit 11C, the X-axis detection circuit 11A, Y and the Z-axis detection circuit 11C are hereinafter collectively or individually referred to as "detection circuits 11". In addition, in the following description, when it is not particularly necessary to distinguish the X-axis correction circuit 12A, Y the axis correction circuit 12B and the Z-axis correction circuit 12C, the X-axis correction circuit 12A, Y the axis correction circuit 12B and the Z-axis correction circuit 12C are hereinafter collectively or individually referred to as "correction circuit 12".

(2.1.1) X-axis detection Circuit

As shown in fig. 1, the X-axis detection circuit 11A includes a CV converter circuit 111, an X-axis first detection unit 112A, and an X-axis second detection unit 113A. In other words, the X-axis detection circuit 11A includes an X-axis first detection unit 112A as the first detection unit 112 and an X-axis second detection unit 113A as the second detection unit 113.

The CV converter circuit 111 converts a change in capacitance caused by the X-axis detection element 2A into a voltage. CV converter circuit 111 includes an amplifier 114, a capacitor 115, and a switch 116. The inverting input terminal of the amplifier 114 is electrically connected to a connection node between two capacitors C1, C2, which form part of the X-axis detection element 2A, C1, C2. The capacitor 115 and the switch 116 are connected in parallel between the inverting input terminal and the output terminal of the amplifier 114. In addition, a reference voltage is input to the non-inverting input terminal of the amplifier 114.

The X-axis first detection unit 112A may be implemented as, for example, an a/D converter. In other words, the first detection unit 112 includes an a/D converter. The X-axis first detection unit 112A generates a digital detection signal Sig2 based on an analog output signal Sig1 supplied from the X-axis detection element 2A via the CV converter circuit 111. The detection signal Sig2 is supplied from the X-axis first detection unit 112A to the subtractor 123 of the X-axis correction circuit 12A described later.

The X-axis second detection unit 113A may be implemented as, for example, an a/D converter. In other words, the second detection unit 113 includes an a/D converter. The X-axis second detection unit 113A generates a digital correction signal Sig3 based on the analog output signal Sig1 supplied from the X-axis detection element 2A via the CV converter circuit 111. The correction signal Sig3 is supplied from the X-axis second detection unit 113A to the first multiplier 121 of the Y-axis correction circuit 12B described later and the first multiplier 121 of the Z-axis correction circuit 12C described later.

(2.1.2) Y-axis detection circuit

As shown in fig. 1, the Y-axis detection circuit 11B includes a CV converter circuit 111, a Y-axis first detection unit 112B, and a Y-axis second detection unit 113B. In other words, the Y-axis detection circuit 11B includes a Y-axis first detection unit 112B as the first detection unit 112 and a Y-axis second detection unit 113B as the second detection unit 113. The CV converter circuit 111 of this Y-axis detection circuit 11B has the same configuration as the CV converter circuit 111 of the X-axis detection circuit 11A described above, and therefore description thereof is omitted herein.

The Y-axis first detection unit 112B may be implemented as, for example, an a/D converter. In other words, the first detection unit 112 includes an a/D converter. The Y-axis first detection unit 112B generates a digital detection signal Sig2 based on an analog output signal Sig1 supplied from the Y-axis detection element 2B via the CV converter circuit 111. The detection signal Sig2 is supplied from the Y-axis first detection unit 112B to the subtractor 123 of the Y-axis correction circuit 12B.

The Y-axis second detection unit 113B may be implemented as, for example, an a/D converter. In other words, the second detection unit 113 includes an a/D converter. The Y-axis second detection unit 113B generates a digital correction signal Sig3 based on the analog output signal Sig1 supplied from the Y-axis detection element 2B via the CV converter circuit 111. The correction signal Sig3 is supplied from the Y-axis second detection unit 113B to the second multiplier 122 of the Z-axis correction circuit 12C and the first multiplier 121 of the X-axis correction circuit 12A.

(2.1.3) Z-axis detection circuit

As shown in fig. 1, the Z-axis detection circuit 11C includes a CV converter circuit 111, a Z-axis first detection unit 112C, and a Z-axis second detection unit 113C. In other words, the Z-axis detection circuit 11C includes a Z-axis first detection unit 112C as the first detection unit 112 and a Z-axis second detection unit 113C as the second detection unit 113. The CV converter circuit 111 of this Z-axis detection circuit 11C has the same configuration as the CV converter circuit 111 of the X-axis detection circuit 11A described above, and therefore description thereof is omitted herein.

The Z-axis first detection unit 112C may be implemented as, for example, an a/D converter. In other words, the first detection unit 112 includes an a/D converter. The Z-axis first detection unit 112C generates a digital detection signal Sig2 based on an analog output signal Sig1 supplied from the Z-axis detection element 2C via the CV converter circuit 111. The detection signal Sig2 is supplied from the Z-axis first detection unit 112C to the subtractor 123 of the Z-axis correction circuit 12C.

The Z-axis second detection unit 113C may be implemented as, for example, an a/D converter. In other words, the second detection unit 113 includes an a/D converter. The Z-axis second detection unit 113C generates a digital correction signal Sig3 based on the analog output signal Sig1 supplied from the Z-axis detection element 2C via the CV converter circuit 111. The correction signal Sig3 is supplied from the Z-axis second detection unit 113C to the second multiplier 122 of the X-axis correction circuit 12A and the second multiplier 122 of the Y-axis correction circuit 12B.

In the present embodiment, for example, if the acceleration detection range of the first detection unit 112 is ± 6G, the acceleration detection range of the second detection unit 113 is preferably ± 30G. This allows the error caused by the other-axis sensitivity to be corrected in a wide range.

(2.1.4) X-axis correction Circuit

As shown in fig. 1, the X-axis correction circuit 12A includes a first multiplier 121, a second multiplier 122, and a subtractor 123.

The first multiplier 121 multiplies the correction signal Sig3 supplied from the Y-axis second detection unit 113B by a correction coefficient a1, and outputs the calculation result to the subtractor 123. The second multiplier 122 multiplies the correction signal Sig3 supplied from the Z-axis second detection unit 113C by the correction coefficient B1, and outputs the calculation result to the subtractor 123. The subtractor 123 subtracts two correction signals Sig3 each multiplied by a correlation correction coefficient from the detection signal Sig2 supplied from the X-axis first detection unit 112A. This allows correction of the other-axis sensitivity in the X-axis direction caused by the acceleration in the Y-axis direction and the other-axis sensitivity in the X-axis direction caused by the acceleration in the Z-axis direction.

(2.1.5) Y-axis correction circuit

As shown in fig. 1, the Y-axis correction circuit 12B includes a first multiplier 121, a second multiplier 122, and a subtractor 123.

The first multiplier 121 multiplies the correction signal Sig3 supplied from the X-axis second detection unit 113A by a correction coefficient a2, and outputs the calculation result to the subtractor 123. The second multiplier 122 multiplies the correction signal Sig3 supplied from the Z-axis second detection unit 113C by the correction coefficient B2, and outputs the calculation result to the subtractor 123. The subtractor 123 subtracts two correction signals Sig3 each multiplied by a correlation correction coefficient from the detection signal Sig2 supplied from the Y-axis first detection unit 112B. This allows correction of the other-axis sensitivity in the Y-axis direction caused by the acceleration in the Z-axis direction and the other-axis sensitivity in the Y-axis direction caused by the acceleration in the X-axis direction.

(2.1.6) Z-axis correction circuit

As shown in fig. 1, the Z-axis correction circuit 12C includes a first multiplier 121, a second multiplier 122, and a subtractor 123.

The first multiplier 121 multiplies the correction signal Sig3 supplied from the X-axis second detection unit 113A by a correction coefficient A3, and outputs the calculation result to the subtractor 123. The second multiplier 122 multiplies the correction signal Sig3 supplied from the Y-axis second detection unit 113B by a correction coefficient B3, and outputs the calculation result to the subtractor 123. The subtractor 123 subtracts two correction signals Sig3 each multiplied by a correlation correction coefficient from the detection signal Sig2 supplied from the Z-axis first detection unit 112C. This allows correction of the other-axis sensitivity in the Z-axis direction caused by the acceleration in the X-axis direction and the other-axis sensitivity in the Z-axis direction caused by the acceleration in the Y-axis direction. These correction coefficients A1-A3, B1-B3 are stored in registers of the ASIC.

(2.2) detection element

Each of the plurality of detecting elements 2 is a detecting element selected from the X-axis detecting element 2A, Y and the Z-axis detecting element 2B and 2C. The X-axis detection element 2A detects an inertial force (acceleration) in the X-axis direction. The Y-axis detector 2B detects an inertial force (acceleration) in the Y-axis direction. The Z-axis detecting element 2C detects an inertial force (acceleration) in the Z-axis direction.

As shown in fig. 3, the inertial sensor 10 according to the present embodiment further includes a housing 21, an upper cover 22, and a lower cover 23. Each of the housing 21, the upper cover 22, and the lower cover 23 is formed in a rectangular parallelepiped shape elongated in the Y-axis direction, and their outer dimensions (the dimension in the X-axis direction and the dimension direction in the Y-axis direction) are substantially the same when viewed in the Z-axis direction.

The X-axis detection element 2A includes a weight 24A, a pair of fixed electrodes 25A, and a pair of moving electrodes 26A, 26A. The weight 24A is formed in a rectangular shape when viewed in the Z-axis direction. Both ends of the weight 24A in the Y-axis direction are fixed to the housing 21 via a pair of beams 27A, 27A. A pair of moving electrodes 26A, 26A are mounted on the upper surface (the surface facing the upper cover 22) of the weight 24A in a state where the pair of moving electrodes 26A, 26A are juxtaposed in the X-axis direction. A pair of fixed electrodes 25A, 25A is mounted on the lower surface (the surface facing the housing 21) of the upper cover 22 in a state where the pair of fixed electrodes 25A, 25A are aligned in the X-axis direction. The pair of fixed electrodes 25A, 25A and the pair of moving electrodes 26A, 26A face each other with a predetermined gap left therebetween in a state where the housing 21 and the upper cover 22 are superposed on each other. The X-axis detection element 2A is configured to swing within the ZX plane with the pair of beams 27A, 27A as fulcrums when acceleration is applied in the X-axis direction.

The Y-axis detection element 2B includes a weight 24B, a pair of fixed electrodes 25B, and a pair of moving electrodes 26B, 26B. The weight 24B is formed in a rectangular shape when viewed in the Z-axis direction. Both ends of the weight 24B in the X-axis direction are fixed to the housing 21 via a pair of beams 27B, 27B. A pair of moving electrodes 26B, 26B are mounted on the upper surface (the surface facing the upper cover 22) of the weight 24B in a state where the pair of moving electrodes 26B, 26B are juxtaposed in the Y-axis direction. A pair of fixed electrodes 25B, 25B are mounted on the lower surface (the surface facing the housing 21) of the upper cover 22 in a state where the pair of fixed electrodes 25B, 25B are aligned in the Y-axis direction. The pair of fixed electrodes 25B, 25B and the pair of moving electrodes 26B, 26B face each other with a predetermined gap left therebetween in a state where the housing 21 and the upper cover 22 are superposed on each other. The Y-axis detection element 2B is configured to swing within the YZ plane with the pair of beams 27B, 27B as fulcrums when acceleration is applied in the Y-axis direction.

The Z-axis detection element 2C includes a weight 24C, a pair of fixed electrodes 25C, and a pair of moving electrodes 26C, 26C (only the upper moving electrode 26C is shown in fig. 3). The weight 24C is formed in a rectangular shape when viewed in the Z-axis direction. The weight 24C is fixed to the housing 21 via four beams 27C, each of which is formed in an L-shape. A pair of moving electrodes 26C, 26C are mounted on both surfaces of the weight 24C in the Z-axis direction. One fixed electrode 25C of the pair of fixed electrodes 25C, 25C is mounted on the lower surface of the upper cover 22. Meanwhile, the other fixed electrode 25C of the pair of fixed electrodes 25C, 25C is mounted on the upper surface of the lower cover 23. In a state where the housing 21, the upper cover 22, and the lower cover 23 are superposed on each other, one fixed electrode 25C of the pair of fixed electrodes 25C, 25C and one moving electrode 26C of the pair of moving electrodes 26C, 26C face each other with a predetermined gap left therebetween. Meanwhile, in a state where the case 21, the upper cover 22, and the lower cover 23 are superposed on each other, the other fixed electrode 25C of the pair of fixed electrodes 25C, 25C and the other moving electrode 26C of the pair of moving electrodes 26C, 26C face each other with a predetermined gap left therebetween. The Z-axis detection element 2C is configured to be movable in the Z-axis direction with the four beams 27C as fulcrums when acceleration is applied in the Z-axis direction.

Fig. 4 is a sectional view taken along the plane X1-X2 shown in fig. 3, and shows the X-axis detecting element 2A. One fixed electrode 25A (shown on the left side of fig. 4) of the pair of fixed electrodes 25A, 25A and one moving electrode 26A (shown on the left side of fig. 4) of the pair of moving electrodes 26A, 26A form a capacitor C1. In addition, the other fixed electrode 25A (shown on the right side of fig. 4) of the pair of fixed electrodes 25A, 25A and the other moving electrode 26A (shown on the right side of fig. 4) of the pair of moving electrodes 26A, 26A form a capacitor C2. It is assumed that acceleration acts on the structure in the direction indicated by the arrow X3 in fig. 4 (hereinafter referred to as "X3 direction"). In this case, the weight 24A of the X-axis detection element 2A swings within the ZX plane with the pair of beams 27A, 27A as fulcrums due to the acceleration thus applied. In the example shown in fig. 4, when acceleration is applied in the X3 direction, the gap between one fixed electrode 25A and one moving electrode 26A becomes wider, and the gap between the other fixed electrode 25A and the other moving electrode 26A becomes narrower. This results in a decrease in the capacitance of the capacitor C1 and an increase in the capacitance of the capacitor C2 as compared with the case where no acceleration is applied in the X3 direction. Therefore, the inertial sensor 10 according to the present embodiment can detect the acceleration applied in the X3 direction based on the capacitance values of the two capacitors C1 and C2.

(3) Operation of

Next, with reference to a sequence diagram shown in fig. 5, the operation of the signal processing apparatus 1 according to the present embodiment is described. In the following description, how to correct an error represented by the other-axis sensitivity in the X-axis direction caused by the acceleration in the Y-axis direction in the case where the acceleration acts in the X-axis direction and the Y-axis direction will be described. Note that in the following description, only the other-axis sensitivity in the X-axis direction will be described, and the description of the other-axis sensitivity in the Y-axis and Z-axis directions is omitted, because almost the same statement applies to the other-axis sensitivity in the Y-axis and Z-axis directions.

Upon detecting the acceleration in the X-axis direction, the X-axis detecting element 2A supplies the output signal Sig1 to the X-axis detecting circuit 11A of the signal processing device 1 (in the first step S1). Meanwhile, in detecting the acceleration in the Y-axis direction, the Y-axis detecting element 2B supplies the output signal Sig1 to the Y-axis detecting circuit 11B (in the first step S1). The output signal Sig1 supplied to the X-axis detection circuit 11A is converted into an analog voltage signal by the CV converter circuit 111, and supplied to the X-axis first detection unit 112A and the X-axis second detection unit 113A. On the other hand, the output signal Sig1 supplied to the Y-axis detection circuit 11B is converted into an analog voltage signal by the CV converter circuit 111, and supplied to the Y-axis first detection unit 112B and the Y-axis second detection unit 113B.

The X-axis first detection unit 112A generates a detection signal Sig2 based on the output signal of the CV converter circuit 111 (in a second step S2). Meanwhile, the Y-axis second detection unit 113B generates a correction signal Sig3 based on the output signal of the CV converter circuit 111 (in a third step S3). The X-axis first detection unit 112A outputs the detection signal Sig2 thus generated to the X-axis correction circuit 12A (in a fourth step S4). On the other hand, the Y-axis second detection unit 113B outputs the correction signal Sig3 thus generated to the X-axis correction circuit 12A (in a fifth step S5).

The X-axis correction circuit 12A generates a detection signal Sig4 in which an error caused by the other-axis sensitivity has been corrected, based on the detection signal Sig2 supplied from the X-axis first detection unit 112A and the correction signal Sig3 supplied from the Y-axis second detection unit 113B (in a sixth step S6). Specifically, the X-axis correction circuit 12A subtracts the product of the correction signal Sig3 and the correction coefficient a1 from the detection signal Sig 2. This allows correction of an error indicated by the other-axis sensitivity in the X-axis direction caused by the acceleration in the Y-axis direction. Then, the X-axis correction circuit 12A outputs the detection signal Sig4 to the control circuit mounted on the printed wiring board 100 (in a seventh step S7).

(4) Advantages of the invention

In the signal processing device 1 according to the present embodiment, the detection range of the second detection unit 113 that generates the correction signal Sig3 is wider than the detection range of the first detection unit 112 that generates the detection signal Sig 2. Therefore, with respect to the acceleration, a decrease in the minimum resolution (signal accuracy) can be suppressed by the first detection unit 112 having a narrower detection range (i.e., a higher minimum resolution) than the second detection unit 113 detecting the acceleration. Meanwhile, with respect to the other-axis sensitivity, even if the magnitude of the acceleration causing the other-axis sensitivity is significant, the influence of the other-axis sensitivity can be reduced by detecting the other-axis sensitivity by the second detection unit 113 having a wider detection range than the first detection unit 112. In short, the signal processing apparatus 1 according to the present embodiment can reduce the influence of the sensitivity of the other axis while suppressing the decrease in the minimum resolution (signal accuracy).

In addition, in the signal processing apparatus 1 according to the present embodiment, the first detection unit 112 and the second detection unit 113 each include an a/D converter. Thus, the analog output signal Sig1 provided from the detection element 2 can be converted into a digital detection signal Sig 2.

In addition, in the signal processing apparatus 1 according to the present embodiment, the detection element 2 includes an X-axis detection element 2A that detects an inertial force in the X-axis direction, a Y-axis detection element 2B that detects an inertial force in the Y-axis direction, and a Z-axis detection element 2C that detects an inertial force in the Z-axis direction. Therefore, the signal processing device 1 can detect the inertial force in the X-axis direction, the inertial force in the Y-axis direction, and the inertial force in the Z-axis direction.

In addition, in the signal processing apparatus 1 according to the present embodiment, the X-axis detection circuit 11A includes an X-axis first detection unit 112A and an X-axis second detection unit 113A, the Y-axis detection circuit 11B includes a Y-axis first detection unit 112B and a Y-axis second detection unit 113B, and the Z-axis detection circuit 11C includes a Z-axis first detection unit 112C and a Z-axis second detection unit 113C. This allows the influence of the sensitivity of the other axis to be reduced in each of the X-axis direction, the Y-axis direction, and the Z-axis direction while suppressing a decrease in the minimum resolution (signal accuracy).

(5) Variants

Note that the above-described embodiment is only one example embodiment among various embodiments of the present disclosure, and should not be construed as a limitation. Rather, the embodiments may be readily modified in various ways depending on design choices or any other factors without departing from the scope of the present disclosure. For example, the functions of the signal processing apparatus 1 according to the above-described embodiments may also be implemented as a signal processing method, a computer program, or a non-transitory storage medium storing a computer program.

A signal processing method according to an aspect is a signal processing method for processing an output signal Sig1 of at least one detection element 2, the at least one detection element 2 detecting inertial forces in at least two of three directions perpendicular to each other. As shown in fig. 5, the signal processing method includes a first detection step (corresponding to the second step S2), a second detection step (corresponding to the third step S3), and a correction step (corresponding to the sixth step S6). The first detecting step includes generating a detection signal Sig2 based on the output signals Sig1 corresponding to the at least two directions. The second detecting step includes generating a correction signal Sig3 based on the output signal Sig1 corresponding to at least two directions within a wider detection range than the first detecting step. The correcting step includes correcting the detection signal Sig 2. The correcting step includes correcting the correlation detection signal Sig2 corresponding to each of the at least two directions using the correlation correction signal Sig3 corresponding to at least one direction other than the one of the at least two directions for which the correction is made.

A program according to another aspect is designed to cause one or more processors to execute the above-described signal processing method.

Next, modifications of the above-described exemplary embodiments will be enumerated one by one. The modifications described below may be employed in appropriate combinations.

The signal processing apparatus 1 according to the present disclosure includes a computer system. The computer system includes a processor and memory as the main hardware components. The functions of the signal processing apparatus 1 according to the present disclosure may be performed by causing a processor to execute a program stored in a memory of a computer system. The program may be stored in advance in the memory of the computer system. Alternatively, the program may be downloaded through a telecommunication line, or may be recorded in a non-transitory storage medium readable by a computer system such as a memory card, an optical disk, or a hard disk drive and then distributed. The processor of the computer system may be implemented as a single or multiple electronic circuits including a semiconductor Integrated Circuit (IC) or a large scale integrated circuit (LSI). As used herein, an "integrated circuit" such as an IC or an LSI is referred to by different names according to its degree of integration. Examples of the integrated circuit include a system LSI, a Very Large Scale Integration (VLSI), and a very large scale integration (ULSI). Alternatively, a Field Programmable Gate Array (FPGA) which is programmed after manufacturing an LSI or a reconfigurable logic device which allows reconfiguration of connections or circuit portions inside the LSI may also be employed as the processor. These electronic circuits may be integrated together on a single chip or distributed over multiple chips, as appropriate. The multiple chips may be integrated together in a single device or distributed among multiple devices, without limitation. As used herein, a "computer system" includes a microcontroller (including one or more processors) and one or more memories. Thus, a microcontroller may also be implemented as a single or multiple electronic circuits including a semiconductor integrated circuit or a large scale integrated circuit.

In addition, in the above-described embodiment, a plurality of constituent elements of the signal processing device 1 are integrated in a single housing. However, this is not a necessary configuration of the signal processing apparatus 1. Alternatively, these constituent elements of the signal processing device 1 may be distributed in a plurality of different housings. Still alternatively, at least some functions of the signal processing apparatus 1 (for example, functions of the correction circuit 12) may also be implemented as a cloud computing system.

(5.1) first modification

A first modification of the inertial sensor 10 according to this embodiment will be described with reference to fig. 6.

As shown in fig. 6, the inertial sensor 10 according to the first modification differs from the inertial sensor 10 according to the above-described embodiment in that a signal comparison unit 13 is included. The inertial sensor 10 according to the first modification has the same configuration as the inertial sensor 10 according to the above-described example embodiment, except for the signal comparison unit 13. Therefore, any constituent element in the inertial sensor 10 according to the first modification that functions in the same way as the counterpart of the above-described example embodiment will be denoted by the same reference numeral as the counterpart, and the description thereof will be omitted herein. Fig. 6 shows an X-axis detection circuit 11A for detecting acceleration in the X-axis direction among the plurality of detection circuits 11.

The inertial sensor 10 according to the first modification includes a plurality of detection elements 2 and a signal processing device 1. In addition, the inertial sensor 10 according to the first modification further includes a signal comparison unit 13. As shown in fig. 6, the signal comparison unit 13 receives the detection signal Sig2 from the first detection unit 112 and the correction signal Sig3 from the second detection unit 113, and compares the values of the detection signal Sig2 and the correction signal Sig 3. The comparison result obtained by the signal comparing unit 13 is supplied to a control circuit mounted on the printed wiring board 100. The control circuit determines that both the first detecting unit 112 and the second detecting unit 113 should operate normally when the values of the detection signal Sig2 and the correction signal Sig3 are found to coincide based on the comparison result supplied from the signal comparing unit 13. On the other hand, the control circuit determines that at least one of the first detection unit 112 and the second detection unit 113 should operate abnormally (malfunction) when the values of the detection signal Sig2 and the correction signal Sig3 are found to be inconsistent with each other based on the comparison result supplied from the signal comparison unit 13. The term "coincident" as used herein refers not only to the case where two values are completely coincident but also to the case where the difference between the two values falls within a predetermined range. Therefore, if the difference between the values of the detection signal Sig2 and the correction signal Sig3 falls within a preset range, the control circuit determines that the values of the detection signal Sig2 and the correction signal Sig3 should coincide.

The inertial sensor 10 according to the first modification includes the signal comparison unit 13, and thus it is possible to determine whether the first detection unit 112 and the second detection unit 113 operate normally.

In this embodiment, in fig. 6, the signal comparing unit 13 is provided for the X-axis detecting circuit 11A for detecting acceleration in the X-axis direction among the plurality of detecting circuits 11. Alternatively, a signal comparison unit may be provided for the Y-axis detection circuit 11B for detecting acceleration in the Y-axis direction, and/or a signal comparison unit may be provided for the Z-axis detection circuit 11C for detecting acceleration in the Z-axis direction. In other words, the signal comparison unit may be provided for at least one of the X-axis detection circuit 11A, Y axis detection circuit 11B or the Z-axis detection circuit 11C.

(5.2) other modifications

In the above-described embodiment, the inertial sensor 10 is implemented as a capacitive sensor. However, the inertial sensor 10 may also be, for example, a piezoresistive sensor.

In the above-described embodiment, the inertial sensor 10 is implemented as a three-axis acceleration sensor. However, the inertial sensor 10 may also be, for example, a biaxial acceleration sensor.

In the above-described embodiment, the acceleration in the X-axis direction, the acceleration in the Y-axis direction, and the acceleration in the Z-axis direction are individually detected by three different detection circuits 11. However, for example, the acceleration in the X-axis direction, the acceleration in the Y-axis direction, and the acceleration in the Z-axis direction may be detected by one detection circuit. In this case, the acceleration in the X-axis direction, the acceleration in the Y-axis direction, and the acceleration in the Z-axis direction may be sequentially detected in time using a multiplexer.

In the above embodiments, the inertial sensor 10 is a surface mount sensor. However, the inertial sensor 10 may also be, for example, a through-hole mount sensor.

In the above embodiment, the inertial sensor 10 is an acceleration sensor. However, the inertial sensor 10 is not necessarily an acceleration sensor, but may be, for example, an angular velocity sensor (gyro sensor).

In the above-described embodiment, the signal processing apparatus 1 is an ASIC. However, the signal processing apparatus 1 is not limited to an ASIC, but may be an FPGA (field programmable gate array), or may be composed of one or more processors and one or more memories.

In the above embodiment, the acceleration in the X-axis direction, the acceleration in the Y-axis direction, and the acceleration in the Z-axis direction are individually detected by three different detecting elements 2. However, for example, the acceleration in the X-axis direction, the acceleration in the Y-axis direction, and the acceleration in the Z-axis direction may be detected by one detection element. Specifically, the detection element may also be realized as a MEMS (micro electro mechanical system) element in which functions of detecting the acceleration in the X-axis direction, the acceleration in the Y-axis direction, and the acceleration in the Z-axis direction are integrated in one chip.

In the above-described embodiment, the first detection unit 112 and the second detection unit 113 are each an a/D converter. However, each of the first detection unit 112 and the second detection unit 113 may also be an operational amplifier, for example. In other words, each of the first and second detecting units 112 and 113 may be an analog circuit. Even when an operational amplifier is used as each of the first detection unit 112 and the second detection unit 113, the same problem occurs in that the sensitivity decreases as the signal detection range increases because there is a trade-off relationship between the detection range and the sensitivity. To overcome this problem, the operational amplifier may be selected such that the signal amplitude of the operational amplifier as the second detection unit 113 is larger than the signal amplitude of the operational amplifier as the first detection unit 112. This configuration can reduce the influence of the sensitivity of the other axis while suppressing the decrease in sensitivity, as with the signal processing apparatus 1 according to the above-described embodiment.

(general)

As can be seen from the above description, the signal processing apparatus (1) according to the first aspect includes a detection circuit (11) and a correction circuit (12). A detection circuit (11) generates a detection signal (Sig2) based on an output signal (Sig1) of at least one detection element (2) that detects inertial forces in at least two directions of three directions perpendicular to each other. A correction circuit (12) corrects the detection signal (Sig 2). The detection circuit (11) includes a first detection unit (112) and a second detection unit (113). The first detection unit (112) generates at least one detection signal (Sig2) based on the correlation output signal (Sig1) corresponding to each of the at least two directions. The second detection unit (113) has a wider detection range than the first detection unit (112) and generates at least one correction signal (Sig3) based on the correlation output signal (Sig1) corresponding to each of the at least two directions. A correction circuit (12) corrects a correlation detection signal (Sig2) corresponding to each of at least two directions using a correlation correction signal (Sig3) corresponding to at least one direction other than the one direction in which the correction is made.

According to this aspect, the second detection unit (113) has a wider detection range than the first detection unit (112). This allows the influence of the sensitivity of the other axis to be reduced while suppressing the decrease in sensitivity.

In a signal processing apparatus (1) according to the second aspect (which may be implemented in combination with the first aspect), each of the first detection unit (112) and the second detection unit (113) includes an a/D converter.

According to this aspect, the analog output signal (Sig1) provided from the detection element (2) may be converted to a digital detection signal (Sig 2).

In a signal processing apparatus (1) according to a third aspect (which may be implemented in combination with the first or second aspect), the at least two directions are an X-axis direction, a Y-axis direction, and a Z-axis direction that are perpendicular to each other. The at least one detection element (2) includes an X-axis detection element (2A), a Y-axis detection element (2B), and a Z-axis detection element (2C). An X-axis detection element (2A) detects an inertial force in the X-axis direction. A Y-axis detection element (2B) detects an inertial force in the Y-axis direction. A Z-axis detection element (2C) detects an inertial force in the Z-axis direction.

This aspect allows detection of the inertial force in the X-axis direction, the inertial force in the Y-axis direction, and the inertial force in the Z-axis direction.

In a signal processing apparatus (1) according to a fourth aspect (which may be implemented in combination with any one of the first to third aspects), the at least two directions are an X-axis direction, a Y-axis direction, and a Z-axis direction that are perpendicular to each other. The detection circuit (11) includes an X-axis detection circuit (11A), a Y-axis detection circuit (11B), and a Z-axis detection circuit (11C). An X-axis detection circuit (11A) generates a correlation detection signal (Sig2) based on a correlation output signal (Sig1) supplied from an X-axis detection element (2A) as at least one detection element (2) that detects an inertial force in an X-axis direction. A Y-axis detection circuit (11B) generates a correlation detection signal (Sig2) on the basis of a correlation output signal (Sig1) supplied from a Y-axis detection element (2B) as at least one detection element (2) that detects an inertial force in a Y-axis direction. A Z-axis detection circuit (11C) generates a correlation detection signal (Sig2) based on a correlation output signal (Sig1) supplied from a Z-axis detection element (2C) as at least one detection element (2) that detects an inertial force in a Z-axis direction. The X-axis detection circuit (11A) includes an X-axis first detection unit (112A) as a first detection unit (112) and an X-axis second detection unit (113A) as a second detection unit (113). The Y-axis detection circuit (11B) includes a Y-axis first detection unit (112B) as a first detection unit (112) and a Y-axis second detection unit (113B) as a second detection unit (113). The Z-axis detection circuit (11C) includes a Z-axis first detection unit (112C) as a first detection unit (112) and a Z-axis second detection unit (113C) as a second detection unit (113).

This aspect allows reducing the influence of the sensitivity of the other axis in each of the X-axis direction, the Y-axis direction, and the Z-axis direction while suppressing the decrease in sensitivity.

The signal processing apparatus (1) according to the fifth aspect, which may be implemented in combination with any one of the first to fourth aspects, further includes a signal comparison unit (13) for comparing each detection signal (Sig2) supplied from the first detection unit (112) with the correlation correction signal (Sig3) supplied from the second detection unit (113).

This aspect allows detecting an operational abnormality (or failure) of at least one of the first detection unit (112) or the second detection unit (113) based on the comparison result provided by the signal comparison unit (13).

An inertial sensor (10) according to a sixth aspect comprises a signal processing device (1) according to any one of the first to fifth aspects and at least one detection element (2).

According to this aspect, the second detection unit (113) has a wider detection range than the first detection unit (112). This allows the influence of the sensitivity of the other axis to be reduced while suppressing the decrease in sensitivity.

A signal processing method according to the seventh aspect is a signal processing method for processing an output signal (Sig1) of at least one detection element (2), the at least one detection element (2) detecting inertial forces in at least two of three directions perpendicular to each other. The signal processing method includes a first detection step (S2), a second detection step (S3), and a correction step (S6). The first detecting step (S2) includes generating a detection signal (Sig2) based on the output signals (Sig1) corresponding to the at least two directions. The second detecting step (S3) includes generating a correction signal (Sig3) based on the output signals (Sig1) corresponding to at least two directions within a wider detection range than the first detecting step (S2). The correcting step (S6) includes correcting the detection signal (Sig 2). The correcting step (S6) includes correcting the correlation detection signal (Sig2) corresponding to each of the at least two directions using at least one correlation correction signal (Sig3) corresponding to at least one direction other than the one direction in which the correction is made.

According to this aspect, the second detection unit (113) has a wider detection range than the first detection unit (112). This allows the influence of the sensitivity of the other axis to be reduced while suppressing the decrease in sensitivity.

A program according to an eighth aspect is designed to cause one or more processors to execute the signal processing method according to the seventh aspect.

According to this aspect, the second detection unit (113) has a wider detection range than the first detection unit (112). This allows the influence of the sensitivity of the other axis to be reduced while suppressing the decrease in sensitivity.

Note that the constituent elements according to the second to fifth aspects are not essential constituent elements of the signal processing apparatus (1), but may be omitted as appropriate.

List of reference numerals

1a signal processing device;

11a detection circuit;

11A X axis detection circuit;

11B Y axis detection circuit;

11C Z axis detection circuit;

110A/D converter;

112a first detection unit;

112A X shaft first detection unit;

112B Y shaft first detection unit;

112C Z shaft first detection unit;

113a second detection unit;

113A X shaft second detection unit;

113B Y shaft second detection unit;

113C Z shaft second detection unit;

12a correction circuit;

13a signal comparison unit;

2a detection element;

2A X axle detecting element;

2B Y axle detecting element;

2C Z axle detecting element;

10 an inertial sensor;

sig1 output signal;

sig2 detects the signal;

sig3 corrects for the signal;

s2 second step (first detection step);

s3 third step (second detection step);

s6 sixth step (correction step).