Multi-axis inertial force sensor

Abstract

To provide a multi-axial inertial force sensor more improved than ever before.SOLUTION: A multi-axial inertial force sensor includes: determination means for determining whether or not a gyro sensor having a failure exists among first to fourth gyro sensors; and detection means for detecting a three-axis angular speed. In the multi-axial inertial force sensor, the determination means has a selection function of selecting a combination of a plurality of groups including one, two, or three gyro sensors in the first to fourth gyro sensors, and a comparison function of comparing angular speeds measured by the gyro sensors of the respective groups. Then, the determination means performs: determining presence / absence of the gyro sensor having a failure from a result of the comparison function, identifying the gyro sensor having a failure, and outputting a failure information signal to the detection means when the gyro sensor having a failure exists. The detection means stops the detection of the three-axis angular speeds using the first to fourth gyro sensors when the failure information signal is input.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology disclosed herein relates to multi-axis inertial forces. [Background technology]

[0002] Patent Document 1 discloses a multi-axis inertial force sensor (multi-axis angular velocity sensor) equipped with four gyro sensors. The multi-axis inertial force sensor of Patent Document 1 calculates the measured values ​​of each gyro sensor and determines that a malfunction has occurred in the multi-axis inertial force sensor if the calculation result is greater than or equal to a predetermined value. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2005-189083 [Overview of the project] [Problems that the invention aims to solve]

[0004] Patent Document 1 can detect whether or not a multi-axis inertial force sensor is malfunctioning. However, it cannot determine the cause of the malfunction. Specifically, it cannot determine whether the entire multi-axis inertial force sensor has malfunctioned (been damaged) or whether one of the multiple gyro sensors constituting the multi-axis inertial force sensor has malfunctioned. Therefore, if a malfunction of the multi-axis inertial force sensor is detected in Patent Document 1, the only solution is to replace the entire multi-axis inertial force sensor. If the cause of the malfunction of the multi-axis inertial force sensor can be identified, other measures can be taken besides replacing the entire multi-axis inertial force sensor. Thus, in multi-axis inertial force sensors, it is necessary not only to detect the presence or absence of malfunction, but also to further improve the functionality. This specification aims to provide a multi-axis inertial force sensor that is improved compared to conventional models. [Means for solving the problem]

[0005] The first embodiment of the multi-axis inertial force sensor disclosed herein includes a base, a first block mounted on the base and having an inclined surface inclined with respect to the surface of the base, a second block mounted on the base and having an inclined surface inclined with respect to the surface of the base, a third block mounted on the base and having an inclined surface inclined with respect to the surface of the base, a fourth block mounted on the base and having an inclined surface inclined with respect to the surface of the base, a first gyro sensor disposed on the inclined surface of the first block, a second gyro sensor disposed on the inclined surface of the second block, a third gyro sensor disposed on the inclined surface of the third block, a fourth gyro sensor disposed on the inclined surface of the fourth block, a determination means for determining whether or not there is a faulty gyro sensor among the first to fourth gyro sensors, and a detection means for detecting the three-axis angular velocity from the measured values ​​of the first to fourth gyro sensors. In this multi-axis inertial force sensor, the first and second blocks are positioned opposite each other along a first direction parallel to the surface of the base, while the third and fourth blocks are positioned opposite each other along a second direction parallel to the surface of the base and perpendicular to the first direction. The determination means includes a selection function to select a combination of multiple groups containing one, two, or three gyro sensors from the first to fourth gyro sensors, a comparison function to compare the angular velocity measured by the gyro sensors in each group, and a determination of whether or not a gyro sensor is malfunctioning based on the results of the comparison function. The determination means identifies the malfunctioning gyro sensor and outputs a malfunction information signal to the detection means if a malfunctioning gyro sensor is present. The detection means stops detecting the three-axis angular velocity using the first to fourth gyro sensors when a malfunction information signal is input.

[0006] The multi-axis inertial force sensor described above can identify a faulty gyroscope sensor. Therefore, in the event of a gyroscope sensor failure, it is possible to take measures other than replacing the entire multi-axis inertial force sensor. Furthermore, since it is possible to identify a faulty gyroscope sensor during use (while the device equipped with the inertial force sensor is operating), the process of identifying a faulty gyroscope sensor after use (inspection for identification) can be omitted.

[0007] The second embodiment of the multi-axis inertial force sensor disclosed herein comprises a base, a first block mounted on the base and having an inclined surface inclined with respect to the surface of the base, a second block mounted on the base and having an inclined surface inclined with respect to the surface of the base, a third block mounted on the base and having an inclined surface inclined with respect to the surface of the base, a fourth block mounted on the base and having an inclined surface inclined with respect to the surface of the base, a first gyro sensor disposed on the inclined surface of the first block, a second gyro sensor disposed on the inclined surface of the second block, a third gyro sensor disposed on the inclined surface of the third block, a fourth gyro sensor disposed on the inclined surface of the fourth block, a determination means for determining whether or not there is a faulty gyro sensor among the first to fourth gyro sensors, a first detection means for detecting a three-axis angular velocity from measured values ​​of the four gyro sensors of the first to fourth gyro sensors, and a first detection means for detecting a three-axis angular velocity from measured values ​​of three of the gyro sensors of the first to fourth gyro sensors. In this multi-axis inertial force sensor, the first and second blocks are positioned opposite each other along a first direction parallel to the surface of the base, while the third and fourth blocks are positioned opposite each other along a second direction parallel to the surface of the base and perpendicular to the first direction. The determination means has a selection function to select a combination of multiple groups containing one, two, or three gyro sensors from the first to fourth gyro sensors, a comparison function to compare the angular velocity measured by the gyro sensors in each group, and a determination function to determine whether there is a faulty gyro sensor based on the results of the comparison function, identify the faulty gyro sensor, and output a fault information signal to the detection means if a faulty gyro sensor exists. The first detection means stops detecting the 3-axis angular velocity when a fault information signal is input. The second detection means detects the 3-axis angular velocity from the three non-faulty gyro sensors when a fault information signal is input.

[0008] The multi-axis inertial force sensor according to the third embodiment disclosed in this specification includes a pedestal, a first block attached to the pedestal and having an inclined surface inclined with respect to the surface of the pedestal, a second block attached to the pedestal and having an inclined surface inclined with respect to the surface of the pedestal, a third block attached to the pedestal and having an inclined surface inclined with respect to the surface of the pedestal, a fourth block attached to the pedestal and having an inclined surface inclined with respect to the surface of the pedestal, a first gyro sensor disposed on the inclined surface of the first block, a second gyro sensor disposed on the inclined surface of the second block, a third gyro sensor disposed on the inclined surface of the third block, a fourth gyro sensor disposed on the inclined surface of the fourth block, a determination means for determining whether there is a failed gyro sensor among the first to fourth gyro sensors, a first detection means for detecting a three-axis angular velocity from the measured values of the four gyro sensors of the first to fourth gyro sensors, and a first detection means for detecting a three-axis angular velocity from the measured values of three gyro sensors among the first to fourth gyro sensors. In this multi-axis inertial force sensor, the first block and the second block are arranged opposite to each other along a first direction parallel to the surface of the pedestal, and the third block and the fourth block are arranged opposite to each other along a second direction parallel to the surface of the pedestal and perpendicular to the first direction. The determination means has a selection function for selecting combinations of a plurality of groups including one, two or three gyro sensors among the first to fourth gyro sensors, a calculation function for calculating an angular velocity using the gyro sensors of each group, a comparison function for comparing the calculated angular velocities, determines the presence or absence of a failed gyro sensor from the result of the comparison function, specifies the failed gyro sensor, and outputs a failure information signal to the detection means when a failed gyro sensor exists. The first detection means stops detecting the three-axis angular velocity when the failure information signal is input. The second detection means detects the three-axis angular velocity from the three non-failed gyro sensors when the failure information signal is input.

[0009] The multi-axis inertial force sensors of the second and third embodiments described above can also identify a failed gyro sensor. Therefore, when a failure occurs in the gyro sensor, measures other than replacing the entire multi-axis inertial force sensor can be taken. Further, since a failed gyro sensor can be identified during use (during the operation of the device equipped with the inertial force sensor), the task of identifying a failed gyro sensor (inspection for identification) after use can be omitted. Furthermore, even if a failure occurs in a gyro sensor, the multi-axis inertial force sensor described above can continue to measure the angular velocity in three axes using the three non-failed gyro sensors. Therefore, even if a failure occurs in a gyro sensor during use, it can continue to be used without performing maintenance or the like.

[0010] In the multi-axis inertial force sensors of the first to third embodiments described above, the determination means may identify a failed gyro sensor based on a combination of groups in which the difference in angular velocity between the groups is greater than a threshold value. Thereby, the group containing the failed gyro sensor is identified, and the failed gyro sensor can be identified from the combination of groups in which the difference in angular velocity is greater than the threshold value.

[0011] In the multi-axis inertial force sensor of the third embodiment described above, the determination means may calculate the angular velocity in a third direction orthogonal to the first direction and the second direction using the gyro sensors of each group. The angular velocity of the third axis can always be measured regardless of the combination of the gyro sensors of each group. Therefore, by calculating the angular velocity in the third direction, it is possible to surely determine the presence or absence of a failure in the gyro sensor and identify the failed gyro sensor.

[0012] In the multi-axis inertial force sensor of the third embodiment described above, the determination means may compare the differences in the calculated angular velocities of each group. The difference between the group containing the failed gyro sensor and the group not containing the failed gyro sensor is larger than the difference between the groups not containing the failed gyro sensor. Therefore, by comparing the differences in the calculated angular velocities of each group, it is possible to determine the presence or absence of a failure in the gyro sensor and identify the failed gyro sensor.

[0013] In the multi-axis inertial force sensors of the first to third embodiments described above, the selection function in the determination means may select a combination of multiple groups, and after confirming the existence of a faulty gyro sensor based on the comparison results of the angular velocity measured by the gyro sensors of each group, it may select another combination of multiple groups to identify the faulty gyro sensor. By separately determining whether a gyro sensor is faulty and identifying the faulty gyro sensor, the process of identifying the faulty gyro sensor can be simplified. Specifically, if no faulty gyro sensors exist, the process of identifying the faulty gyro sensor itself can be omitted.

[0014] In the third embodiment of the multi-axis inertial force sensor described above, the determination means may: the selection function selects two combinations of groups, each containing two of the four gyro sensors, so that all four gyro sensors are included; the identification function calculates the angular velocity in a third direction orthogonal to the first and second directions from the two combinations of groups containing two gyro sensors, and identifies the presence or absence of a faulty gyro sensor based on the combination of groups whose difference in the calculated angular velocities of the two groups is greater than a threshold; if a faulty gyro sensor exists, the selection function selects three combinations of groups from four groups, each containing three of the four gyro sensors, and the identification function calculates the angular velocity in the third direction from the three combinations of groups containing three gyro sensors, and identifies the faulty gyro sensor based on the combination of groups whose difference in the calculated angular velocities of the three groups is greater than a threshold.

[0015] The above-mentioned gyro sensor also simplifies the process of identifying a faulty gyro sensor by separately determining whether a gyro sensor is faulty and identifying the faulty gyro sensor. Furthermore, the number of groups selected when detecting whether a gyro sensor is faulty and the number of groups selected when identifying a faulty gyro sensor can be reduced, thereby decreasing the number of calculations required in the comparison function. [Brief explanation of the drawing]

[0016] [Figure 1] A perspective view of a multi-axis inertial force sensor is shown. [Figure 2] A detailed diagram of the block sensor is shown. [Figure 3] A diagram illustrating the principle of measuring three-axis angular velocity is shown. [Figure 4] The internal structure of a multi-axis inertial force sensor is schematically shown. [Figure 5] A diagram illustrating the method for identifying a fault in the gyro sensor of the first embodiment is shown. [Figure 6] A diagram illustrating the method for identifying a fault in the gyro sensor in the second embodiment is shown. [Figure 7] A diagram illustrating the method for identifying a fault in the gyro sensor of the third embodiment is shown. [Figure 8] A diagram illustrating the method for identifying a fault in the gyro sensor in the fourth embodiment is shown. [Figure 9] A diagram illustrating the method for identifying a fault in the gyro sensor in the fifth embodiment is shown. [Figure 10] This shows a flowchart for detecting failures in a multi-axis inertial force sensor. [Modes for carrying out the invention]

[0017] The inertial force sensor 60 will be described with reference to Figures 1 to 4. The inertial force sensor 60 is an example of a multi-axis inertial force sensor, and although details will be described later, it is a 3-axis angular velocity sensor. As shown in Figure 1, the inertial force sensor 60 comprises a base 2, a first block sensor 10a, a second block sensor 10b, a third block sensor 10c, and a fourth block sensor 10d. The first block sensor 10a comprises a first block 4a and a first gyro sensor 6a. The second block sensor 10b comprises a second block 4b and a second gyro sensor 6b. The third block sensor 10c comprises a third block 4c and a third gyro sensor 6c. The fourth block sensor 10d comprises a fourth block 4d and a fourth gyro sensor 6d. The block sensors 10a to 10d are fixed (mounted) on the surface of the base 2. Blocks 4a to 4d are made of the same material, and block sensors 10a to 10d have substantially the same structure. The inertial force sensor 60 is a three-axis angular velocity sensor that detects angular velocity around the X, Y, and Z axes.

[0018] The surface of base 2 is parallel to the XY plane. The first block sensor 10a and the second block sensor 10b are positioned opposite each other in the X-axis direction. The X-axis direction is an example of the first direction. Specifically, the first block 4a and the second block 4b are positioned opposite each other in the X-axis direction so that their inclined surfaces 22 (see Figure 2) face inward. The third block sensor 10c and the fourth block sensor 10d are positioned opposite each other in the Y-axis direction. The Y-axis direction is an example of the second direction. That is, the third block 4c and the fourth block 4d are positioned opposite each other in the Y-axis direction so that their inclined surfaces 22 face inward.

[0019] Figure 2 shows a detailed view of the block sensor 10 (block sensors 10a to 10d). The gyro sensor 6 is fixed to the inclined surface 22 of block 4 by solder 30. Block 4 is made of LCP (Liquid Crystal Polymer) resin. Also fixed to the inclined surface 22 by solder (not shown) is a socket 34 into which several electronic components (chip resistors, chip capacitors, etc.) 32 and an FPC (Flexible Printed Circuits) 36 are fitted. The gyro sensor 6 and the electronic components 32 are connected to wiring 40 via solder, and are connected to a circuit calculation output unit (not shown) located outside the block sensor 10 via the FPC 36. The wiring 40 is a thin metallic film formed on the surface of the inclined surface 22 by surface modification using MID (Molded Interconnect Device) technology, and is directly formed on the inclined surface 22 of block 4.

[0020] The gyro sensor 6 detects angular velocity on one axis. Specifically, the gyro sensor 6 is a so-called Z-axis gyro sensor that detects angular velocity in a direction perpendicular to the mounting surface (inclined surface 22). The gyro sensor 6 has a QFN (Quad Flat Non-lead package) structure. The power and GND of the gyro sensor 6 are supplied from the circuit calculation output unit described above. The detection signal from the gyro sensor 6 is also output to the circuit calculation output unit.

[0021] In addition, instead of LCP resin, metal can be used as the material for block 4. If metal is used as the material for block 4, the gyro sensor 6, angular velocity sensor 8, electronic components 32 and socket 34 are mounted on a printed circuit board with a wiring pattern, and this printed circuit board is mounted on block 4.

[0022] As described above, the inertial force sensor 60 can detect angular velocities in the X, Y, and Z axes. The measurement principle by which the inertial force sensor 60 detects the three-axis angular velocities will be explained below.

[0023] FIG. 3 schematically shows (a) two block sensors (block sensors 10a and 10b) arranged in the X-axis direction and (b) two block sensors (block sensors 10c and 10d) arranged in the Y-axis direction. The angles θ1 formed by the pedestal 2 and the first gyro sensor 6a, the angle θ2 formed by the pedestal 2 and the second gyro sensor 6b, the angle θ3 formed by the pedestal 2 and the third gyro sensor 6c, and the angle θ4 formed by the pedestal 2 and the fourth gyro sensor 6d are shown.

[0024] For example, when an angular velocity “ω x ” around the X-axis is applied to the inertial force sensor 60, “-ω x ” is applied to the first gyro sensor 6a, and “ω x ” is applied to the second gyro sensor 6b (a). Also, in this case, “ω x ” is not applied to the third gyro sensor 6c and the fourth gyro sensor 6d. This is because the third block 4c and the fourth block 4d are arranged side by side in the Y-axis direction and are insensitive to the angular velocity around the X-axis, which is the other axis.

[0025] Also, when an angular velocity “ω y ” around the Y-axis is applied to the inertial force sensor 60, “-ω y ” is applied to the third gyro sensor 6c, and “ω y ” is applied to the fourth gyro sensor 6d (b). Also, in this case, “ω y ” is not applied to the first gyro sensor 6a and the second gyro sensor 6b. This is because the first block 4a and the second block 4b are arranged side by side in the X-axis direction and are insensitive to the angular velocity around the Y-axis, which is the other axis.

[0026] When an angular velocity “ω z ” around the Z-axis is applied to the inertial force sensor 60, “ω z ” is applied to all the gyro sensors 6a to 6d. That is, the angular velocity “ω zAll gyro sensors 6a to 6d can detect this. Gyroscopes 6a to 6d are gyro sensors (Z-axis gyro sensors) that detect angular velocity around directions perpendicular to the surface (S1, S2, S3, S4 directions). Specifically, the principal axis (detection axis) of the first gyro sensor 6a is in the S1 direction, the principal axis of the second gyro sensor 6b is in the S2 direction, the principal axis of the third gyro sensor 6c is in the S3 direction, and the principal axis of the fourth gyro sensor 6d is in the S4 direction.

[0027] The angular velocity "ω" is measured by the inertial force sensor 60. x ", "ω y " and "ω z When '' is applied, it is necessary that angular velocity be applied to the principal axis of each gyro sensor 6a to 6d. For example, if the output signals of each gyro sensor 6a to 6d are S1, S2, S3, and S4 respectively, then each output signal can be expressed by the following equation (1). Furthermore, when equation (1) is expressed as a matrix, it becomes the following equation (2). The inertial force sensor 60 can detect the 3-axis angular velocity based on the following equation (1) or (2).

[0028]

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[0029] Since the inertial force sensor 60 controls the relative positions of blocks 4a to 4d using the base 2, it can detect the three-axis angular velocity with high accuracy based on equations (1) and (2) described above.

[0030] Furthermore, the inertial force sensor 60 can detect 3-axis angular velocity using three of the gyro sensors 6a to 6d. Therefore, even if, for example, one of the gyro sensors 6a to 6d fails, the 3-axis angular velocity can still be detected. For example, if the first gyro sensor 6a or the second gyro sensor 6b fails, the 3-axis angular velocity can be detected based on the matrix equations (3) and (4) below. Note that "θ"1,2 ", "S 1,2 " represents "θ1 or θ2" and "S1 or S2", respectively.

[0031]

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[0032] Furthermore, if the third gyro sensor 6c or the fourth gyro sensor 6d fails, the three-axis angular velocity can be detected based on the matrix equations (5) and (6) below. 3,4 ", "S 3,4 " represents "θ3 or θ4" and "S3 or S4", respectively.

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[0033] Next, with reference to Figure 4, the internal configuration of the inertial force sensor 60 will be described. As mentioned above, the inertial force sensor 60 can detect 3-axis angular velocity using four gyro sensors 6a to 6d, or it can detect axial angular velocity using three of the four gyro sensors 6a to 6d. The inertial force sensor 60 has two means for detecting 3-axis angular velocity.

[0034] The inertial force sensor 60 comprises a sensing unit 62 and a circuit calculation output unit 63. The sensing unit 62 has an implementation structure with the block sensor 10 shown in Figure 1. The circuit calculation output unit 63 calculates the sensor output input from the sensing unit 62 and outputs a sensor signal of 3-axis angular velocity to the outside. The circuit calculation output unit 63 also supplies the output of the DC power supply 90 external to the inertial force sensor 60 to the sensing unit 62. Furthermore, the circuit calculation output unit 63 receives the angular velocity measurement result from the sensing unit 62 via SPI communication.

[0035] The circuit calculation output unit 63 includes a first detection means 72, a determination means 64, a second detection means 68, and a switching means 70. The first detection means 72 detects the three-axis angular velocity using four gyro sensors 6a to 6d. The determination means 64 determines whether or not the gyro sensors 6a to 6d are faulty and identifies the faulty gyro sensor. Specifically, the determination means 64 has a selection function to select some of the gyro sensors 6a to 6d, a calculation function to calculate the angular velocity (one-axis angular velocity) using the selected gyro sensors, a comparison function to compare the calculated angular velocities, and an identification function to determine whether or not the gyro sensors 6a to 6d are faulty and to identify the faulty gyro sensor based on the comparison results. Furthermore, if a faulty gyro sensor is confirmed, the determination means 64 outputs a fault error signal to the switching means 70. The error signal is an example of a fault information signal. In addition, the determination means outputs information about the gyro sensor that has been identified as faulty to the second detection means 68. Details regarding the selection, calculation, comparison, and specific functions will be described later.

[0036] The second detection means 68 uses the three normal gyro sensors (3 gyro sensors) other than the gyro sensor identified as faulty by the determination means 64 to detect the 3-axis angular velocity. When the switching means receives an error signal from the determination means 64, it switches the signal (3-axis angular velocity) to be output externally from the detected value obtained by the first detection means 72 to the detected value obtained by the second detection means 68.

[0037] As described above, the inertial force sensor 60 determines whether or not the gyro sensors 6a to 6d are faulty and identifies the faulty gyro sensor. Below, several embodiments of the method for determining whether or not the gyro sensors 6a to 6d are faulty and identifying the faulty gyro sensor will be described.

[0038] (First embodiment) In the inertial force sensor 60 shown in Figure 1, a combination of four groups including one gyro sensor from among gyro sensors 6a to 6d is selected (selection function), and the Z-axis angular velocity of each group is measured (calculation function). Then, the difference in the Z-axis angular velocity of each group is calculated and the calculation result is compared with a set threshold (comparison function) to determine whether or not gyro sensors 6a to 6d are faulty and to identify the faulty gyro sensor (identification function). The angular velocity of each group is calculated using the following equation (7) (see also Figure 3). In the following equation (7), "a" means one of 1, 2, 3, or 4.

[0039]

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[0040] Calculating the difference in Z-axis angular velocity for each group yields six results, "A" to "F," as shown in Figure 5. In Figure 5, "ω z1 " is the Z-axis angular velocity of the first gyro sensor 6a, and "ω z2 " is the Z-axis angular velocity of the second gyro sensor 6b, and "ω z3 " is the Z-axis angular velocity of the third gyro sensor 6c, and "ω z4 This represents the Z-axis angular velocity of the fourth gyro sensor 6d.

[0041] If all gyro sensors 6a to 6d are functioning correctly (not malfunctioning), theoretically the angular velocity results for each group will be equal, and theoretically the results for "A" to "F" will be "0". However, in reality, there is variation in the angular velocity results for each group, so the values ​​for "A" to "F" are often other than "0". However, if all gyro sensors 6a to 6d are functioning correctly, the values ​​(absolute values) for "A" to "F" will be small numbers that do not exceed the threshold.

[0042] However, if, for example, the first gyro sensor 6a is faulty, the values ​​of "A", "B", and "C" will be large, exceeding the threshold. That is, if the first gyro sensor 6a is faulty, but the other gyro sensors 6b, 6c, and 6d are not, the values ​​of "A", "B", and "C" will exceed the threshold, while the values ​​of "D", "E", and "F" will not. In this way, the presence or absence of faults among the gyro sensors 6a to 6d and the faulty gyro sensor can be identified.

[0043] If the second gyro sensor 6b fails, but the other gyro sensors 6a, 6c, and 6d do not fail, the values ​​for "A", "D", and "E" will exceed the threshold, while the values ​​for "B", "C", and "F" will not exceed the threshold. If the third gyro sensor 6c fails, but the other gyro sensors 6a, 6b, and 6d do not fail, the values ​​for "B", "D", and "F" will exceed the threshold, while the values ​​for "A", "C", and "E" will not exceed the threshold. If the fourth gyro sensor 6d fails, but the other gyro sensors 6a, 6b, and 6c do not fail, the values ​​for "C", "E", and "F" will exceed the threshold, while the values ​​for "A", "B", and "D" will not exceed the threshold.

[0044] (Second example) In the inertial force sensor 60 shown in Figure 1, a combination of six groups, each containing two gyro sensors from among gyro sensors 6a to 6d, is selected (selection function), and the Z-axis angular velocity of each group is measured (calculation function). Subsequently, the difference in the Z-axis angular velocity of each group is calculated, and the calculation result is compared with a set threshold (comparison function) to determine whether or not gyro sensors 6a to 6d are faulty and to identify the faulty gyro sensor (identification function). The angular velocity of each group is calculated using the following equation (8) (see also Figure 3). In the following equation (8), "a" means 1, 2, or 3, and "b" means one of 2, 3, or 4.

[0045]

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[0046] Calculating the difference in Z-axis angular velocity for each group yields 15 results, labeled "A" to "O" as shown in Figure 6. In Figure 6, "ω z12 " is the Z-axis angular velocity of the group of the first gyro sensor 6a and the second gyro sensor 6b, and "ω z13 " is the Z-axis angular velocity of the group of the first gyro sensor 6a and the third gyro sensor 6c, and "ω z14 " is the Z-axis angular velocity of the group of the first gyro sensor 6a and the fourth gyro sensor 6d, and "ω z23 " is the Z-axis angular velocity of the group of the second gyro sensor 6b and the third gyro sensor 6c, and "ω z24 " is the Z-axis angular velocity of the group of the second gyro sensor 6b and the fourth gyro sensor 6d, and "ω z34 " represents the Z-axis angular velocity of the group consisting of the third gyro sensor 6c and the fourth gyro sensor 6d. If all gyro sensors 6a to 6d are functioning correctly, the values ​​(absolute values) of "A" to "O" will be small values ​​that do not exceed the threshold. The identification method in this embodiment involves a large number of calculations (comparisons) of the difference in Z-axis angular velocity, allowing for highly accurate determination of whether or not gyro sensors 6a to 6d are faulty and identification of the faulty gyro sensor.

[0047] In this embodiment, if the first gyro sensor 6a fails but the other gyro sensors 6b, 6c, and 6d do not fail, the values ​​of "C", "D", "E", "G", "H", "I", "J", "K", and "L" will exceed the threshold, while the values ​​of "A", "B", "F", "M", "N", and "O" will not exceed the threshold. If the second gyro sensor 6b fails but the other gyro sensors 6a, 6c, and 6d do not fail, the values ​​of "A", "B", "E", "G", "H", "J", "K", "N", and "O" will exceed the threshold, while the values ​​of "C", "D", "F", "I", "L", and "M" will not exceed the threshold. If the third gyro sensor 6c fails, but the other gyro sensors 6a, 6b, and 6d do not fail, the values ​​of "A", "C", "E", "F", "H", "J", "L", "M", and "O" will exceed the threshold, while the values ​​of "B", "D", "G", "I", "K", and "N" will not exceed the threshold. If the fourth gyro sensor 6d fails, but the other gyro sensors 6a, 6b, and 6c do not fail, the values ​​of "B", "D", "E", "F", "H", "I", "J", "M", and "N" will exceed the threshold, while the values ​​of "A", "C", "G", "K", "L", and "O" will not exceed the threshold.

[0048] (Third embodiment) In the inertial force sensor 60 shown in Figure 1, a combination of four groups, each containing three gyro sensors from among gyro sensors 6a to 6d, is selected (selection function), and the Z-axis angular velocity of each group is measured (calculation function). Subsequently, the difference in the Z-axis angular velocity of each group is calculated, and the calculation result is compared with a set threshold (comparison function) to determine whether or not gyro sensors 6a to 6d are faulty and to identify the faulty gyro sensor (identification function). The angular velocity of each group is calculated using the following formula (9) (see also Figure 3). In formula (9) below, "a" means 1 or 2, "b" means 2 or 3, and "c" means 3 or 4.

[0049]

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[0050] Calculating the difference in Z-axis angular velocity for each group yields six results, "A" to "F," as shown in Figure 7. In Figure 6, "ω z123 " is the Z-axis angular velocity of the group consisting of the first gyro sensor 6a, the second gyro sensor 6b, and the third gyro sensor 6c, and "ω z124 " is the Z-axis angular velocity of the group of the first gyro sensor 6a, the second gyro sensor 6b, and the fourth gyro sensor 6d, and "ω z134 " is the Z-axis angular velocity of the group consisting of the first gyro sensor 6a, the third gyro sensor 6c, and the fourth gyro sensor 6d, and "ω z234 " represents the Z-axis angular velocity of the group consisting of the second gyro sensor 6b, the third gyro sensor 6c, and the fourth gyro sensor 6d. If all gyro sensors 6a to 6d are functioning correctly, the values ​​(absolute values) of "A" to "F" will be small values ​​that do not exceed the threshold. The identification method in this embodiment calculates the difference in Z-axis angular velocity using the three gyro sensors, so it is possible to determine whether or not there is a malfunction in gyro sensors 6a to 6d and to identify the faulty gyro sensor with high accuracy.

[0051] In this embodiment, if the first gyro sensor 6a fails but the other gyro sensors 6b, 6c, and 6d do not fail, the values ​​of "C", "E", and "F" will exceed the threshold, while the values ​​of "A", "B", and "D" will not exceed the threshold. If the second gyro sensor 6b fails but the other gyro sensors 6a, 6c, and 6d do not fail, the values ​​of "B", "D", and "F" will exceed the threshold, while the values ​​of "A", "C", and "E" will not exceed the threshold. If the third gyro sensor 6c fails but the other gyro sensors 6a, 6b, and 6d do not fail, the values ​​of "A", "D", and "E" will exceed the threshold, while the values ​​of "B", "C", and "F" will not exceed the threshold. If the fourth gyro sensor 6d fails, but the other gyro sensors 6a, 6b, and 6c are not failing, the values ​​of "A", "B", and "C" will exceed the threshold, while the values ​​of "D", "E", and "F" will not exceed the threshold.

[0052] (Fourth embodiment) This embodiment is a modification of the second and third embodiments. In the inertial force sensor 60 shown in Figure 1, a combination of two groups is selected from six groups containing two gyro sensors from gyro sensors 6a to 6d, and a combination of three groups is selected from four groups containing three gyro sensors from gyro sensors 6a to 6d (selection function), and the Z-axis angular velocity of each group is measured (calculation function). The two groups containing two gyro sensors are selected so that all gyro sensors 6a to 6d are included. Then, the difference in the Z-axis angular velocity of each group is calculated and the calculation result is compared with a set threshold (comparison function) to determine whether or not there is a malfunction in gyro sensors 6a to 6d and to identify the malfunctioning gyro sensor (identification function). The angular velocity of each group is calculated using the above equations (8) and (9).

[0053] Calculating the difference in Z-axis angular velocity for each group yields 10 results labeled "A" to "J" as shown in Figure 8. z12 ", "ω z34 ", "ω z123 ", "ω z124 ", "ω z134 " is the Z-axis angular velocity of the group described in the second and third embodiments. If all gyro sensors 6a to 6d are functioning correctly, the values ​​(absolute values) of "A" to "F" will be small values ​​that do not exceed the threshold. The identification method in this embodiment allows for the detection of faults in gyro sensors 6a to 6d and the identification of faulty gyro sensors with high accuracy, while reducing the number of calculations (comparisons) for the difference in Z-axis angular velocity compared to the second embodiment, by selecting a portion of the group containing two gyro sensors and a portion of the group containing three gyro sensors.

[0054] In this embodiment, if the first gyro sensor 6a fails but the other gyro sensors 6b, 6c, and 6d do not fail, the values ​​of "A", "E", "F", and "G" will exceed the threshold, while the values ​​of "B", "C", "D", "H", "I", and "J" will not exceed the threshold. If the second gyro sensor 6b fails but the other gyro sensors 6a, 6c, and 6d do not fail, the values ​​of "A", "D", "E", "F", "I", and "J" will exceed the threshold, while the values ​​of "B", "C", "G", and "H" will not exceed the threshold. If the third gyro sensor 6c fails but the other gyro sensors 6a, 6b, and 6d do not fail, the values ​​of "A", "B", "D", "F", "H", and "J" will exceed the threshold, while the values ​​of "C", "E", "G", and "I" will not exceed the threshold. If the fourth gyro sensor 6d fails, but the other gyro sensors 6a, 6b, and 6c do not fail, the values ​​of "A", "C", "D", "E", "H", and "I" will exceed the threshold, while the values ​​of "B", "F", "G", and "J" will not exceed the threshold.

[0055] (Fifth example) This embodiment is a modification of the fourth embodiment. In this embodiment, first, in the inertial force sensor 60 shown in Figure 1, a combination of two groups is selected from six groups that include two gyro sensors from among the gyro sensors 6a to 6d (selection function), and only the presence or absence of a malfunction in the gyro sensors 6a to 6d is determined. The two groups that include two gyro sensors are selected so that all of the gyro sensors 6a to 6d are included. Subsequently, if a malfunction is determined, a combination of three groups is selected from four groups that include three gyro sensors from among the gyro sensors 6a to 6d (selection function), and the Z-axis angular velocity of each group is measured (calculation function). That is, if a gyro sensor malfunctions, the selection function operates intermittently twice, with the malfunction determination in between. Subsequently, the difference in the Z-axis angular velocity of each group is calculated, and the calculation result is compared with a set threshold (comparison function) to identify the malfunctioning gyro sensor (identification function). The angular velocity of each group is calculated using the above equations (8) and (9).

[0056] Two groups of Z-axis angular velocity "ω" including two gyro sensors z12 ", "ωz34 If we calculate the difference between ", then if all gyro sensors 6a to 6d are working correctly, then "ω z12 ", "ω z34 The numerical difference (absolute value) of " will be a small number that does not exceed the threshold. On the other hand, if there is a malfunctioning gyro sensor, "ω z12 ", "ω z34 The numerical difference (absolute value) of " exceeds the threshold. In this example, "ω z12 ", "ω z34 If the difference in numerical value (absolute value) of " exceeds the threshold, the 3 groups of Z-axis angular velocity "ω z123 ", "ω z124 ", "ω z134 The Z-axis angular velocity of each group is measured and the difference is calculated. Four results, "A" to "D" shown in Figure 9, are obtained as the difference in Z-axis angular velocity for each group. In this embodiment, the identification method first identifies whether or not there is a malfunction in the gyro sensors 6a to 6d, and only if there is a malfunction, the faulty gyro sensor is identified. As a result, the presence or absence of a malfunction in the gyro sensors 6a to 6d and the identification of the faulty gyro sensor can be performed with high accuracy while suppressing an increase in the number of measurements (calculations).

[0057] In this embodiment, if the first gyro sensor 6a fails but the other gyro sensors 6b, 6c, and 6d do not fail, the value of "A" exceeds the threshold, while the values ​​of "B", "C", and "D" do not exceed the threshold. If the second gyro sensor 6b fails but the other gyro sensors 6a, 6c, and 6d do not fail, the values ​​of "A", "C", and "D" exceed the threshold, while the value of "B" does not exceed the threshold. If the third gyro sensor 6c fails but the other gyro sensors 6a, 6b, and 6d do not fail, the values ​​of "A", "B", and "D" exceed the threshold, while the value of "C" does not exceed the threshold. If the fourth gyro sensor 6d fails but the other gyro sensors 6a, 6b, and 6c do not fail, the values ​​of "A", "B", and "C" exceed the threshold, while the value of "D" does not exceed the threshold.

[0058] Figure 10 shows the fault detection process for gyro sensors 6a to 6d in the inertial force sensor 60. The inertial force sensor 60 typically uses four gyro sensors 6a to 6d, as shown in step S2, to measure the three-axis angular velocity using equations (1) and (2) above (first detection means). A combination of multiple groups containing one to three gyro sensors is selected from the four gyro sensors 6a to 6d (step S4: selection function). Then, the Z-axis angular velocity of each group is calculated (step S6), and the difference in the Z-axis angular velocity of each group is compared with a threshold (step S8). If the difference in Z-axis angular velocity is smaller than the threshold, it is determined that there is no fault, and the process returns to step S4 (step S10: NO). In other words, the measurement of the three-axis angular velocity using the four gyro sensors 6a to 6d continues.

[0059] If a faulty device is detected (Step S10: YES), the process proceeds to Step S12, where the circuit calculation output unit 63 outputs an error signal to the switching means 70 (see Figure 4). The switching means 70 stops the first detection means (which measures the 3-axis angular velocity using the four gyro sensors 6a to 6d) (Step S14) and determines whether or not the faulty device can be identified (Step S16). That is, the switching means 70 determines whether or not it can measure the 3-axis angular velocity using the three gyro sensors 6a to 6d and the above equations (3) to (6). If it is possible to measure the 3-axis angular velocity using the three gyro sensors 6a to 6d (Step S16: YES), the switching means 70 switches the measurement of the 3-axis angular velocity to the second detection means (Step S18). Subsequently, the inertial force sensor 60 measures the 3-axis angular velocity using the three gyro sensors and the above equations (3) to (6). If it is not possible to measure the three-axis angular velocity using the three gyro sensors 6a to 6d (step S16: NO), the system will notify that there is a malfunction in the inertial force sensor 60 (step S20).

[0060] The inertial force sensor 60 disclosed in this embodiment can be suitably used, for example, in autonomous driving systems for vehicles and autonomous driving systems for aircraft such as drones. As described above, the inertial force sensor 60 can not only detect when a gyro sensor 6a to 6d has failed, but also identify which gyro sensor has failed and continue measuring the three-axis angular velocity with the gyro sensor that is not failing. Therefore, even if a gyro sensor fails, the estimation of the self-position (current path) can be continued, and there is no need to interrupt use (driving, flying). In addition, since the three-axis angular velocity is measured with the gyro sensor that is not failing when a gyro sensor fails, accurate estimation of the self-position can be performed. Furthermore, by identifying which gyro sensor has failed, the work of identifying the failed gyro sensor (inspection for identification) after use can be omitted.

[0061] In the inertial force sensor 60, a single-axis gyro sensor (Z-axis gyro sensor) with one detection axis is used as the gyro sensor, but a two-axis gyro sensor with two detection axes or a three-axis gyro sensor with three detection axes can also be used.

[0062] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. Furthermore, the technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness. [Explanation of Symbols]

[0063] 2: Pedestal 4: Block 6: Gyroscope sensor 60: Inertial force sensor 64: Circuit calculation output section

Claims

1. The base and A first block is attached to a base and has an inclined surface that is inclined with respect to the surface of the base, A second block is attached to a base and has an inclined surface that is inclined with respect to the surface of the base, A third block is attached to a base and has an inclined surface that is inclined with respect to the surface of the base, A fourth block is attached to a base and has an inclined surface that is inclined with respect to the surface of the base, The first gyro sensor is positioned on the inclined surface of the first block, The second gyro sensor is located on the inclined surface of the second block, The third gyro sensor is located on the inclined surface of the third block, The fourth gyro sensor is located on the inclined surface of the fourth block, A means for determining whether or not there is a faulty gyro sensor among the first to fourth gyro sensors, A detection means for detecting the three-axis angular velocity from the measurements of the first to fourth gyro sensors, It is equipped with, The first and second blocks are arranged opposite each other along a first direction parallel to the surface of the base. The third and fourth blocks are positioned opposite each other along a second direction that is parallel to the surface of the base and perpendicular to the first direction. The determination means includes a selection function to select a combination of multiple groups containing one, two, or three gyro sensors from the first to fourth gyro sensors, a comparison function to compare the angular velocity measured by the gyro sensors in each group, and a determination of whether or not there is a faulty gyro sensor based on the results of the comparison function, the identification of the faulty gyro sensor, and if a faulty gyro sensor is present, a fault information signal to the detection means. The detection means is a multi-axis inertial force sensor that stops detecting the three-axis angular velocity using the first to fourth gyro sensors when a fault information signal is input.

2. The base and A first block is attached to a base and has an inclined surface that is inclined with respect to the surface of the base, A second block is attached to a base and has an inclined surface that is inclined with respect to the surface of the base, A third block is attached to a base and has an inclined surface that is inclined with respect to the surface of the base, A fourth block is attached to a base and has an inclined surface that is inclined with respect to the surface of the base, The first gyro sensor is positioned on the inclined surface of the first block, The second gyro sensor is located on the inclined surface of the second block, The third gyro sensor is located on the inclined surface of the third block, The fourth gyro sensor is located on the inclined surface of the fourth block, A means for determining whether or not there is a faulty gyro sensor among the first to fourth gyro sensors, A first detection means for detecting the three-axis angular velocity from the measured values ​​of four gyro sensors, from the first to the fourth gyro sensors, A second detection means for detecting the three-axis angular velocity from the measured values ​​of three of the first to fourth gyro sensors, It is equipped with, The first and second blocks are arranged opposite each other along a first direction parallel to the surface of the base. The third and fourth blocks are positioned opposite each other along a second direction that is parallel to the surface of the base and perpendicular to the first direction. The determination means includes a selection function to select a combination of multiple groups containing one, two, or three gyro sensors from the first to fourth gyro sensors, a comparison function to compare the angular velocity measured by the gyro sensors in each group, and a determination of whether or not there is a faulty gyro sensor based on the results of the comparison function, the identification of the faulty gyro sensor, and if a faulty gyro sensor is present, a fault information signal to the detection means. The first detection means stops detecting the three-axis angular velocity when a fault information signal is input. The second detection means is a multi-axis inertial force sensor that, when a fault information signal is input, detects the three-axis angular velocity from three non-faulty gyro sensors.

3. The base and A first block is attached to a base and has an inclined surface that is inclined with respect to the surface of the base, A second block is attached to a base and has an inclined surface that is inclined with respect to the surface of the base, A third block is attached to a base and has an inclined surface that is inclined with respect to the surface of the base, A fourth block is attached to a base and has an inclined surface that is inclined with respect to the surface of the base, The first gyro sensor is positioned on the inclined surface of the first block, The second gyro sensor is located on the inclined surface of the second block, The third gyro sensor is located on the inclined surface of the third block, The fourth gyro sensor is located on the inclined surface of the fourth block, A means for determining whether or not there is a faulty gyro sensor among the first to fourth gyro sensors, A first detection means for detecting the three-axis angular velocity from the measured values ​​of four gyro sensors, from the first to the fourth gyro sensors, A second detection means for detecting the three-axis angular velocity from the measured values ​​of three of the first to fourth gyro sensors, It is equipped with, The first and second blocks are arranged opposite each other along a first direction parallel to the surface of the base. The third and fourth blocks are positioned opposite each other along a second direction that is parallel to the surface of the base and perpendicular to the first direction. The determination means includes a selection function for selecting a combination of multiple groups containing one, two, or three gyro sensors from the first to fourth gyro sensors, a calculation function for calculating angular velocity using the gyro sensors in each group, a comparison function for comparing the calculated angular velocities, and a function for determining whether a gyro sensor is faulty based on the results of the comparison function, identifying the faulty gyro sensor, and outputting a fault information signal to the detection means if a faulty gyro sensor is present. The first detection means stops detecting the three-axis angular velocity when a fault information signal is input. The second detection means is a multi-axis inertial force sensor that, when a fault information signal is input, detects the three-axis angular velocity from three non-faulty gyro sensors.

4. The multi-axis inertial force sensor according to any one of claims 1 to 3, wherein the determination means identifies a faulty gyro sensor based on a combination of groups in which the difference in angular velocity between each group is greater than a threshold.

5. The multi-axis inertial force sensor according to claim 3, wherein the determination means uses the gyro sensors of each group to calculate the angular velocity in a third direction orthogonal to the first and second directions.

6. The determination means is a multi-axis inertial force sensor according to claim 3, which compares the difference in angular velocity of each group calculated.

7. The multi-axis inertial force sensor according to any one of claims 1 to 3, wherein the determination means includes a selection function which selects a combination of multiple groups, and after it is confirmed that there is a faulty gyro sensor based on the comparison results of the angular velocity measured by the gyro sensors of each group, it selects a combination of multiple groups again in order to identify the faulty gyro sensor.

8. In the means of judgment, The selection function selects two combinations of gyro sensors, each containing two of the four gyro sensors, so that all four gyro sensors are included. The specific function calculates the angular velocity in a third direction orthogonal to the first and second directions from combinations of two groups containing two gyro sensors, and identifies the presence or absence of a faulty gyro sensor based on the combination of groups where the difference between the calculated angular velocities of the two groups is greater than a threshold. If a faulty gyro sensor is present, the selection function will select a combination of three groups from four groups, each containing three of the four gyro sensors. The multi-axis inertial force sensor according to claim 3, wherein the specific function calculates the angular velocity in a third direction from combinations of three groups, each containing three gyro sensors, and identifies a faulty gyro sensor based on the combination of groups whose difference in the calculated angular velocities of the three groups is greater than a threshold.

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