Sensor device

Abstract

To provide a sensor device capable of accurately estimating a correction coefficient to correct an error occurring in an angular velocity signal due to misalignment of an angular velocity sensor.SOLUTION: Provided is a sensor device comprising, assuming that mutually orthogonal three axes consist of a first axis, a second axis, and a third axis: a first angular velocity sensor for detecting an angular velocity around the first axis and outputting a first angular velocity signal; a second angular velocity sensor for detecting an angular velocity around the second axis and outputting a second angular velocity signal; a third angular velocity sensor for detecting an angular velocity around the third axis and outputting a third angular velocity signal; a fourth angular velocity sensor for detecting an angular velocity around a fourth axis corresponding to the third axis and outputting a fourth angular velocity signal; and a correction circuit for estimating a correction coefficient to correct an error of the fourth angular velocity signal due to deviation of the fourth axis with respect to the third axis, on the basis of the first angular velocity signal, the second angular velocity signal, the third angular velocity signal, and the fourth angular velocity signal.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a sensor device. [Background technology]

[0002] Patent Document 1 describes an inertial measurement device that includes an inertial sensor including a three-axis angular velocity sensor and a high-precision Z-axis angular velocity sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-158425 A Summary of the Invention [Problem to be solved by the invention]

[0004] When a high-precision Z-axis angular velocity sensor is provided separately from an inertial sensor including a triaxial angular velocity sensor, as in the inertial measurement device described in Patent Document 1, misalignment may occur between the triaxial angular velocity sensor and the Z-axis angular velocity sensor. This misalignment may cause an error in the angular velocity signal output from the Z-axis angular velocity sensor. [Means for solving the problem]

[0005] One aspect of the sensor device according to the present invention is When three mutually orthogonal axes are defined as the first axis, the second axis, and the third axis, a first axis angular velocity sensor that detects an angular velocity about the first axis and outputs a first angular velocity signal; a second axis angular velocity sensor that detects an angular velocity about the second axis and outputs a second angular velocity signal; a third axis angular velocity sensor that detects an angular velocity about the third axis and outputs a third angular velocity signal; a fourth axis angular velocity sensor that detects an angular velocity around a fourth axis corresponding to the third axis and outputs a fourth angular velocity signal; a correction circuit that estimates a correction coefficient for correcting an error in the fourth angular velocity signal due to a deviation of the fourth axis with respect to the third axis, based on the first angular velocity signal, the second angular velocity signal, the third angular velocity signal, and the fourth angular velocity signal; Equipped with. [Brief description of the drawings]

[0006] [Figure 1] FIG. 2 is a cross-sectional view showing the structure of a main part of the sensor device according to the embodiment. [Diagram 2] An explanatory diagram of the X-axis, Y-axis, and Z-axis. [Diagram 3] FIG. 1 is a diagram showing the configuration of a sensor system. [Figure 4] FIG. 2 is a diagram showing a configuration example of an angular velocity sensor. [Diagram 5] FIG. 2 is a diagram showing a configuration example of an inertial sensor. [Figure 6] FIG. 2 is a diagram showing an example of the configuration of a processing device. [Figure 7] FIG. 11 is a diagram showing a flow of processing by a correction circuit using a Kalman filter. [Figure 8] FIG. 13 is a diagram showing an example of time series data of ωx,k, ωy,k, ωz,k, and Ωz,k. [Figure 9] FIG. 13 is a diagram showing time series data of alignment correction coefficients c1, k, c2, k, and c3, k. [Figure 10] FIG. 13 is a graph showing time series data of deviation of Z-axis angular velocity before and after correction processing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Note that the embodiments described below do not unduly limit the contents of the present invention described in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

[0008] 1. Embodiment 1-1. Structure of the sensor device First, the structure of the sensor device of this embodiment will be described. Fig. 1 is a cross-sectional view showing the structure of a main part of a sensor device 2 of this embodiment. As shown in Fig. 1, the sensor device 2 includes an angular velocity sensor 10, an inertial sensor 20, and a processing device 30. Also, as shown in Fig. 1, the sensor device 2 includes a mounting substrate 4 on which the angular velocity sensor 10, the inertial sensor 20, and the processing device 30 are mounted.

[0009] The mounting substrate 4 is, for example, a multi-layer substrate with a plurality of through holes, and a glass epoxy substrate is used. However, the mounting substrate 4 is not limited to a glass epoxy substrate, and may be any rigid substrate on which the angular velocity sensor 10, the inertial sensor 20, and the processing device 30 can be mounted, and may be, for example, a composite substrate or a ceramic substrate.

[0010] The angular velocity sensor 10 and the processing device 30 are mounted on the first surface 4a of the mounting substrate 4 and are solidified by a molding resin 5 having a substantially rectangular parallelepiped shape. The molding resin 5 makes the angular velocity sensor 10 and the processing device 30 less susceptible to impact, temperature, humidity, and the like. The inertial sensor 20 is mounted on the second surface 4b of the mounting substrate 4, which is opposite to the first surface 4a. Since the angular velocity sensor 10 is mounted on the first surface 4a of the mounting substrate 4 and the inertial sensor 20 is mounted on the second surface 4b of the mounting substrate 4, the size of the mounting substrate 4 can be reduced, thereby realizing area saving. The angular velocity sensor 10 and the inertial sensor 20 are each electrically connected to the processing device 30 by wiring (not shown) provided on the mounting substrate 4. In addition, a plurality of electronic components such as a temperature sensor may be mounted on the mounting substrate 4.

[0011] A plurality of external connection terminals 6 extend from the second surface 4b of the mounting substrate 4. Each external connection terminal 6 is electrically connected to a functional terminal of the processing device 30, a power supply terminal, and a ground terminal of each of the angular velocity sensor 10, the inertial sensor 20, and the processing device 30 by wiring (not shown) provided on the mounting substrate 4.

[0012] The sensor device 2 is composed of a structure consisting of an angular velocity sensor 10, an inertial sensor 20, a processing device 30, a mounting substrate 4, a molding resin 5 and a plurality of leads, and a mounting substrate (not shown) on which the structure is mounted, which are contained in a housing (not shown).

[0013] The inertial sensor 20 detects an angular velocity around the first axis, an angular velocity around the second axis, and an angular velocity around the third axis, where three mutually orthogonal axes are a first axis, a second axis, and a third axis. In this embodiment, the inertial sensor 20 further detects an acceleration in a first axis direction, an acceleration in a second axis direction, and an acceleration in a third axis direction. That is, in this embodiment, the inertial sensor 20 is a 6DOF sensor that detects angular velocities around three axes and an acceleration in three axis directions. DOF is an abbreviation for Degrees Of Freedom. For example, the inertial sensor 20 is a capacitance type sensor in which a silicon substrate is processed by MEMS technology. MEMS is an abbreviation for Micro Electro Mechanical Systems.

[0014] The angular velocity sensor 10 detects the angular velocity around a fourth axis corresponding to the third axis. For example, the angular velocity sensor 10 is a vibration gyro sensor that has a sensor element made of quartz and detects the angular velocity from the Coriolis force applied to a vibrating object. In this embodiment, the detection accuracy of the angular velocity around the fourth axis by the angular velocity sensor 10 is higher than the detection accuracy of the angular velocity around the third axis by the inertial sensor 20.

[0015] In the following description, the first axis is the X-axis, the second axis is the Y-axis, the third axis is the Z-axis, and the fourth axis is the Z'-axis.

[0016] The angular velocity sensor 10 and the inertial sensor 20 are housed in one housing so that the Z'-axis and the Z-axis are in the same direction, forming a sensor device 2 that detects angular velocities around three axes and acceleration in the three axial directions. Ideally, the Z'-axis coincides with the Z-axis, but in reality, since the angular velocity sensor 10 and the inertial sensor 20 are separate bodies, there is a possibility that the Z'-axis and the Z-axis are slightly misaligned. The processing device 30 corrects the angular velocity around the Z'-axis detected by the angular velocity sensor 10 by estimating the misalignment between the Z'-axis and the Z-axis. The processing device 30 is, for example, an MCU, and is configured as a one-chip IC. MCU is an abbreviation for Micro Controller Unit, and IC is an abbreviation for Integrated Circuit.

[0017] The sensor device 2 is fixed to a surface of an object to be attached, such as an automobile or a robot, and detects the behavior of the object. The object to be attached is not limited to a moving body such as an automobile, but may be a structure such as a bridge or an elevated track. When the sensor device is attached to a structure, it is used, for example, as a structural health monitoring system that checks the soundness of the structure.

[0018] 2, when the sensor device 2 is mounted on the automobile 400, the sensor device 2 is attached so that, for example, the X-axis is aligned with the traveling direction of the automobile 400, the Y-axis is aligned with the rightward direction perpendicular to the traveling direction, and the Z-axis is aligned with the downward direction perpendicular to the traveling direction. The angular velocity sensor 10 detects the angular velocity around the Z'-axis corresponding to the Z-axis, and the inertial sensor 20 detects the angular velocity around the X-axis, the angular velocity around the Y-axis, the angular velocity around the Z-axis, the acceleration in the X-axis direction, the acceleration in the Y-axis direction, and the acceleration in the Z-axis direction. The sensor device 2 may output data including the angular velocity around the Z-axis corrected for the angular velocity around the Z'-axis detected by the angular velocity sensor 10, and the angular velocities around the three axes and the acceleration in the three axes detected by the inertial sensor 20. Also, for example, the sensor device 2 may output data including an angular velocity around the Z-axis corrected from the angular velocity around the Z'-axis detected by the angular velocity sensor 10, and the angular velocity around the X-axis, the angular velocity around the Y-axis, and the acceleration in the three axial directions detected by the inertial sensor 20.

[0019] 2, the sensor device 2 may output data including a roll angle φ, a pitch angle θ, and a yaw angle ψ that represent the attitude of the automobile 400. The roll angle φ is a rotation angle about an X-axis along the traveling direction of the automobile 400. The pitch angle θ is a rotation angle about a Y-axis along a rightward direction perpendicular to the traveling direction of the automobile 400. The yaw angle ψ is a rotation angle about a Z-axis along a downward direction perpendicular to the traveling direction of the automobile 400.

[0020] 1-2. Sensor system configuration Next, a configuration and functions of a sensor system 1 using the sensor device 2 will be described. A functional configuration of the sensor device 2 will also be described. FIG. 3 is a diagram showing the configuration of the sensor system 1. As shown in FIG. 3, the sensor system 1 includes the sensor device 2 and a host device 3.

[0021] The sensor device 2 includes an angular velocity sensor 10, an inertial sensor 20, and a processing device 30. Note that the sensor device 2 may have a configuration in which some of the components in FIG. 3 are omitted or modified, or other components are added.

[0022] As described above, the angular velocity sensor 10 is an angular velocity sensor that detects the angular velocity around the Z' axis. FIG.

[0023] 4, the angular velocity sensor 10 includes an angular velocity sensor element 11 and a processing circuit 12. For example, the angular velocity sensor 10 may be a device in which a printed circuit board on which the angular velocity sensor element 11 and the processing circuit 12 are mounted is housed in a package. The processing circuit 12 may be, for example, an IC chip realized by a semiconductor. The angular velocity sensor 10 has terminals TCS1, TCK1, TDI1, TDO1, and TR1 that are external connection terminals provided in the package.

[0024] The angular velocity sensor element 11 is a sensor element made of quartz crystal, and detects angular velocity around the Z' axis, which is the detection axis.

[0025] The processing circuit 12 performs an angular velocity detection process on the signal output from the angular velocity sensor element 11, and outputs a detection signal SD1 obtained by the detection process. The processing circuit 12 includes a detection circuit 121 that performs an angular velocity detection process on the signal output from the angular velocity sensor element 11, and an interface circuit 122 that outputs the detection signal SD1 obtained by the detection process of the detection circuit 121.

[0026] The detection circuit 121 acquires the signal output from the angular velocity sensor element 11 at a predetermined period and performs a predetermined calculation to generate a detection signal SD1. The detection signal SD1 includes a Z'-axis angular velocity detection signal SD1GZ' obtained based on the output signal from the angular velocity sensor element 11. In addition, the detection circuit 121 generates a data ready signal DRDY1 notifying completion of preparation of the detection signal SD1 every time generation of the detection signal SD1 is completed. The detection signal SD1 is output to the interface circuit 122, and the data ready signal DRDY1 is output from a terminal TR1 and input to a terminal TMR1 of the processing device 30.

[0027] The interface circuit 122 acquires the detection signal SD1 output from the detection circuit 121 in response to a read command input from the processing device 30, and outputs the acquired detection signal SD1 to the processing device 30.

[0028] Returning to the description of FIG. 3, as described above, the inertial sensor 20 is a 6DOF sensor that detects angular velocities around three axes, namely, the X-axis, the Y-axis, and the Z-axis, and accelerations in three axial directions, namely, the X-axis, the Y-axis, and the Z-axis. FIG. 5 is a diagram showing a configuration example of the inertial sensor 20. As shown in FIG. 5, the inertial sensor 20 includes angular velocity sensor elements 21X, 21Y, and 21Z, acceleration sensor elements 22X, 22Y, and 22Z, and a processing circuit 23. For example, the inertial sensor 20 may be a silicon MEMS sensor in which a silicon substrate on which the angular velocity sensor elements 21X, 21Y, and 21Z, the acceleration sensor elements 22X, 22Y, and 22Z, and the processing circuit 23 are formed, is housed in a package. The inertial sensor 20 has a terminal TCS2, a terminal TCK2, a terminal TDI2, a terminal TDO2, and a terminal TR2 that are terminals for external connection provided in the package.

[0029] Angular velocity sensor element 21X is a sensor element that detects angular velocity around the X-axis using the X-axis as its detection axis. Angular velocity sensor element 21Y is a sensor element that detects angular velocity around the Y-axis using the Y-axis as its detection axis. Angular velocity sensor element 21Z is a sensor element that detects angular velocity around the Z-axis using the Z-axis as its detection axis.

[0030] The acceleration sensor element 22X is a sensor element that detects acceleration in the X-axis direction using the X-axis as its detection axis. The acceleration sensor element 22Y is a sensor element that detects acceleration in the Y-axis direction using the Y-axis as its detection axis. The acceleration sensor element 22Z is ​​a sensor element that detects acceleration in the Z-axis direction using the Z-axis as its detection axis.

[0031] The processing circuit 23 performs angular velocity detection processing on the signals output from the angular velocity sensor elements 21X, 21Y, and 21Z, and performs acceleration detection processing on the signals output from the acceleration sensor elements 22X, 22Y, and 22Z, and outputs a detection signal SD2 obtained by the detection processing. The processing circuit 23 includes a detection circuit 231 that performs detection processing on the signals output from the angular velocity sensor elements 21X, 21Y, and 21Z and the acceleration sensor elements 22X, 22Y, and 22Z, and an interface circuit 232 that outputs the detection signal SD2 obtained by the detection processing of the detection circuit 231.

[0032] The detection circuit 231 acquires the signals output from the angular velocity sensor elements 21X, 21Y, and 21Z and the acceleration sensor elements 22X, 22Y, and 22Z at a predetermined cycle, and performs a predetermined calculation to generate a detection signal SD2. The detection signal SD2 includes an X-axis angular velocity detection signal SD2GX obtained based on the output signal of the angular velocity sensor element 21X, a Y-axis angular velocity detection signal SD2GY obtained based on the output signal of the angular velocity sensor element 21Y, and a Z-axis angular velocity detection signal SD2GZ obtained based on the output signal of the angular velocity sensor element 21Z. Furthermore, the detection signal SD2 includes an X-axis acceleration detection signal SD2AX obtained based on the output signal of the acceleration sensor element 22X, a Y-axis acceleration detection signal SD2AY obtained based on the output signal of the acceleration sensor element 22Y, and a Z-axis acceleration detection signal SD2AZ obtained based on the output signal of the acceleration sensor element 22Z. In addition, the detection circuit 231 generates a data ready signal DRDY2 that indicates the completion of preparation of the detection signal SD2 every time the generation of the detection signal SD2 is completed. The detection signal SD2 is output to the interface circuit 232, and the data ready signal DRDY2 is output from the terminal TR2 and input to the terminal TMR2 of the processing device 30.

[0033] The interface circuit 232 acquires the detection signal SD2 output from the detection circuit 231 in response to a read command input from the processing device 30, and outputs the acquired detection signal SD2 to the processing device 30.

[0034] Returning to the description of FIG. 3, the sensor device 2 includes a digital interface bus BS that electrically connects the angular velocity sensor 10 and the inertial sensor 20 to the processing device 30 .

[0035] The digital interface bus BS is a bus that complies with the communication standard of the interface processing performed by the interface circuits 122 and 232. In this embodiment, the digital interface bus BS is a bus that complies with the communication standard of SPI, and includes two data signal lines, a clock signal line, and a chip select signal line. SPI is an abbreviation of Serial Peripheral Interface. Specifically, the angular velocity sensor 10 is electrically connected to the digital interface bus BS via the terminals TCS1, TCK1, TDI1, and TDO1. The inertial sensor 20 is electrically connected to the digital interface bus BS via the terminals TCS2, TCK2, TDI2, and TDO2. The processing device 30 is electrically connected to the digital interface bus BS via the terminals TMCS1, TMCS2, TMCK, TMDO, and TMDI. Here, the term "electrically connected" means that an electrical signal can be transmitted, and is a connection that allows information to be transmitted by an electrical signal. However, the digital interface bus BS may be a bus conforming to the I2C communication standard, a communication standard developed from SPI or I2C, or a communication standard that is an improvement or modification of part of the SPI or I2C standard. I2C is an abbreviation for Inter-Integrated Circuit.

[0036] The processing device 30 is a master controller for the angular velocity sensor 10 and the inertial sensor 20. The processing device 30 is an integrated circuit device and is realized by a processor such as an MCU. Alternatively, the processing device 30 may be realized by an ASIC using automatic placement and wiring such as a gate array.

[0037] The processing device 30 outputs a chip select signal XMCS1 from a terminal TMCS1, outputs a chip select signal XMCS2 from a terminal TMCS2, outputs a serial clock signal MSCLK from a terminal TMCK, and outputs a serial data signal MSDI from a terminal TMDO.

[0038] The interface circuit 122 performs interface processing of the SPI communication standard based on the chip select signal XMCS1 input from the terminal TCS1, the serial clock signal MSCLK input from the terminal TCK1, and the serial data signal MSDI input from the terminal TDI1, and outputs the detection signal SD1 to the terminal TDO1 when the serial data signal MSDI is a read command for the detection signal SD1.

[0039] The interface circuit 232 performs interface processing of the SPI communication standard based on the chip select signal XMCS2 input from the terminal TCS2, the serial clock signal MSCLK input from the terminal TCK2, and the serial data signal MSDI input from the terminal TDI2, and outputs the detection signal SD2 to the terminal TDO2 when the serial data signal MSDI is a read command for the detection signal SD2.

[0040] The detection signal SD1 output from the terminal TDO1 of the angular velocity sensor 10 and the detection signal SD2 output from the terminal TDO2 of the inertial sensor 20 are each input to the terminal TMDI of the processing device 30 as a serial data signal MSDO.

[0041] The processing device 30 receives the detection signal SD1 output from the angular velocity sensor 10 and the detection signal SD2 output from the inertial sensor 20, and outputs measurement data based on the detection signals SD1 and SD2. Specifically, when a data ready signal DRDY1 is input from the terminal TMR1, the processing device 30 outputs a read command for the detection signal SD1 to the angular velocity sensor 10 to read the detection signal SD1, and performs various arithmetic processing on the detection signal SD1. When a data ready signal DRDY2 is input from the terminal TMR2, the processing device 30 outputs a read command for the detection signal SD2 to the inertial sensor 20 to read the detection signal SD2, and performs various arithmetic processing on the detection signal SD2.

[0042] For example, the processing device 30 may perform a temperature correction calculation, a sensitivity correction calculation, an offset correction calculation, an alignment correction calculation, and the like, on the detection signals SD1 and SD2. The temperature correction calculation is a calculation for correcting the detection signals SD1 and SD2 to reduce the temperature dependency of the detection signals SD1 and SD2 by increasing or decreasing the detection signals SD1 and SD2 according to the temperature detected by a temperature sensor (not shown) within a predetermined temperature range. The sensitivity correction calculation is a calculation for correcting the detection sensitivity of each axis to a reference value. The offset correction calculation is a calculation for correcting the zero point of each axis to a reference value. The alignment correction calculation is a calculation for correcting an error due to a deviation between the detection axis of each sensor element and the X-axis, Y-axis, or Z-axis of the sensor device 2.

[0043] Furthermore, the processing device 30 may perform calculations to calculate the attitude, speed, angle, etc. of the sensor device 2 based on the detection signals SD1 and SD2.

[0044] If the period for performing the series of calculations is longer than each period of the data ready signals DRDY1 and DRDY2, the processing device 30 may perform a downsampling calculation to thin out a part of the detection signals SD1 and SD2.

[0045] In this embodiment, the processing device 30 is electrically connected to the host device 3 via the terminals THCS, THCK, THDI, THDO, and THR. The host device 3 is a controller that serves as a master for the processing device 30. The processing device 30 outputs a data ready signal DRDY, which indicates the completion of preparation of measurement data, from the terminal THR to the host device 3 every time a series of calculations for the detection signals SD1 and SD2 is completed. The host device 3 outputs a chip select signal XHCS, a serial clock signal HSCLK, and a serial data signal HSDI, which is a read command for measurement data, conforming to the SPI communication standard, to the processing device 30 every time the data ready signal DRDY is input from the terminal THR. The processing device 30 performs interface processing of the SPI communication standard based on the chip select signal XHCS input from the terminal THCS, the serial clock signal HSCLK input from the terminal THCK, and the serial data signal HSDI input from the terminal THDI, and outputs the measurement data to the terminal THDO. The measurement data output from the terminal THDO of the processing device 30 is input to the host device 3 as a serial data signal HSDO. However, the processing device 30 may perform interface processing such as an I2C communication standard, a communication standard developed from SPI or I2C, or a communication standard that is an improvement or modification of part of the SPI or I2C standard.

[0046] As described above, the acceleration sensor element 22X of the inertial sensor 20 detects the acceleration in the X-axis direction. Therefore, the processing device 30 derives the X-axis acceleration measurement data A based on the X-axis acceleration detection signal SD2AX included in the detection signal SD2. X Generate X-axis acceleration measurement data A from host device 3 X When a read command is received, the generated X-axis acceleration measurement data A X Similarly, the acceleration sensor element 22Y of the inertial sensor 20 detects acceleration in the Y-axis direction. Therefore, the processing device 30 outputs Y-axis acceleration measurement data A based on the Y-axis acceleration detection signal SD2AY included in the detection signal SD2. Y Generate Y-axis acceleration measurement data A from host device 3 YWhen a read command is received, the generated Y-axis acceleration measurement data A Y Similarly, the acceleration sensor element 22Z of the inertial sensor 20 detects acceleration in the Z-axis direction. Therefore, the processing device 30 outputs Z-axis acceleration measurement data A based on the Z-axis acceleration detection signal SD2AZ included in the detection signal SD2. Z and generate Z-axis acceleration measurement data A from host device 3. Z When the read command is received, the generated Z-axis acceleration measurement data A Z Output.

[0047] As described above, the angular velocity sensor element 21X of the inertial sensor 20 detects the angular velocity around the X-axis. Therefore, the processing device 30 calculates the X-axis angular velocity measurement data G based on the X-axis angular velocity detection signal SD2GX included in the detection signal SD2. X and generates X-axis angular velocity measurement data G from the host device 3. X When the read command is received, the generated X-axis angular velocity measurement data G X Similarly, the angular velocity sensor element 21Y of the inertial sensor 20 detects an angular velocity around the Y-axis. Therefore, the processing device 30 outputs the Y-axis angular velocity measurement data G based on the Y-axis angular velocity detection signal SD2GY included in the detection signal SD2. Y and transmits Y-axis angular velocity measurement data G Y When the read command is received, the generated Y-axis angular velocity measurement data G YOn the other hand, the angular velocity sensor element 21Z of the inertial sensor 20 detects the angular velocity around the Z-axis, and the angular velocity sensor element 11 of the angular velocity sensor 10 detects the angular velocity around the Z'-axis corresponding to the Z-axis. In this embodiment, the angular velocity sensor element 11 is an element made of quartz, whereas the angular velocity sensor element 21Z is an element formed from a silicon substrate using MEMS technology. Therefore, the angular velocity sensor 10 having the angular velocity sensor element 11 has high frequency temperature characteristics and frequency stability, and low noise and jitter, and therefore high detection accuracy, compared to the inertial sensor 20 having the angular velocity sensor element 21Z. Therefore, the processing device 30 detects the Z-axis angular velocity measurement data G based on the Z'-axis angular velocity detection signal SD1GZ' included in the detection signal SD1. Z and generates Z-axis angular velocity measurement data G from the host device 3. Z When the read command is received, the generated Z-axis angular velocity measurement data G Z As will be described later, in this embodiment, the processing device 30 generates a Z-axis angular velocity detection signal SD1GZ in which an error in the Z'-axis angular velocity detection signal SD1GZ' caused by a deviation of the Z'-axis with respect to the Z-axis is corrected, and calculates the Z-axis angular velocity measurement data G based on the Z-axis angular velocity detection signal SD1GZ. Z Generate.

[0048] The host device 3 receives the X-axis angular velocity measurement data G X , Y-axis angular velocity measurement data G Y , Z-axis angular velocity measurement data G Z , X-axis acceleration measurement data A X , Y-axis acceleration measurement data A Y and Z-axis acceleration measurement data A Z Upon receiving the command, the processing device 30 may transmit a command to read out the measurement data including the X-axis angular velocity measurement data G X , Y-axis angular velocity measurement data G Y , Z-axis angular velocity measurement data G Z , X-axis acceleration measurement data A X , Y-axis acceleration measurement data A Y and Z-axis acceleration measurement data A Z Send.

[0049] 1-3. Processing device configuration Next, a specific configuration of the processing device 30 will be described. Fig. 6 is a diagram showing an example of the configuration of the processing device 30. As shown in Fig. 6, the processing device 30 includes a digital interface circuit 31, a processing circuit 32, a host interface circuit 33, and a memory 34.

[0050] The digital interface circuit 31 is a circuit that performs interface processing with the angular velocity sensor 10 and the inertial sensor 20. That is, the digital interface circuit 31 performs interface processing as a master between the interface circuit 122 and the interface circuit 232. The digital interface circuit 31 is connected to the digital interface bus BS via the terminals TMCS1, TMCS2, TMCK, TMDO, and TMDI. In this embodiment, the digital interface circuit 31 performs interface processing of the SPI communication standard, similar to the interface circuits 122 and 232. However, the digital interface circuit 31 may perform interface processing of the I2C communication standard, a communication standard developed from the SPI or I2C, or a communication standard improved or modified from a part of the SPI or I2C standard. The digital interface bus BS and the digital interface circuit 31 may be provided in common for the angular velocity sensor 10 and the inertial sensor 20, or may be provided separately for the angular velocity sensor 10 and the inertial sensor 20.

[0051] The host interface circuit 33 is a circuit that performs interface processing with the host device 3. That is, the host interface circuit 33 performs interface processing as a slave with the host device 3. The host interface circuit 33 performs interface processing of the SPI communication standard with the host device 3 via the terminals THCS, THCK, THDO, and THDI. However, the host interface circuit 33 may also perform interface processing of the I2C communication standard, a communication standard developed from SPI or I2C, or a communication standard that is an improvement or modification of a part of the SPI or I2C standard.

[0052] The processing circuit 32 performs control processing of the digital interface circuit 31 and the host interface circuit 33, various arithmetic processing, etc. The processing circuit 32 includes a register unit 321, a detection signal acquisition circuit 322, a correction circuit 323, and an arithmetic circuit 324. The processing circuit 32 may perform control processing and arithmetic processing by executing a program (not shown) stored in a non-volatile memory 34.

[0053] The register unit 321 includes various registers.

[0054] The detection signal acquisition circuit 322 outputs a read command for the detection signal SD1 to the angular velocity sensor 10 via the digital interface circuit 31 every time a data ready signal DRDY1 is input from the terminal TMR1, and acquires the detection signal SD1 output from the angular velocity sensor 10 via the digital interface circuit 31. In addition, the detection signal acquisition circuit 322 outputs a read command for the detection signal SD2 to the inertial sensor 20 via the digital interface circuit 31 every time a data ready signal DRDY2 is input from the terminal TMR2, and acquires the detection signal SD2 output from the inertial sensor 20 via the digital interface circuit 31.

[0055] As described above, the inertial sensor 20 functions as an X-axis angular velocity sensor that detects an angular velocity around the X-axis and outputs an X-axis angular velocity detection signal SD2GX. The inertial sensor 20 also functions as a Y-axis angular velocity sensor that detects an angular velocity around the Y-axis and outputs a Y-axis angular velocity detection signal SD2GY. The inertial sensor 20 also functions as a Z-axis angular velocity sensor that detects an angular velocity around the Z-axis and outputs a Z-axis angular velocity detection signal SD2GZ. The X-axis angular velocity sensor, the Y-axis angular velocity sensor, and the Z-axis angular velocity sensor are integrally mounted on the first surface 4a of the mounting substrate 4 as the inertial sensor 20. Therefore, in the manufacturing stage of the inertial sensor 20, the X-axis, the Y-axis, and the Z-axis have already been adjusted so that they are mutually orthogonal. In contrast, the angular velocity sensor 10 is mounted on the second surface 4b of the mounting substrate 4 as a separate body from the inertial sensor 20 that functions as the X-axis angular velocity sensor, the Y-axis angular velocity sensor, and the Z-axis angular velocity sensor, so that the Z'-axis and the Z-axis are easily misaligned. If the Z' axis deviates from the Z axis, the Z' axis will no longer be perpendicular to the X and Y axes, and therefore the angular velocity sensor 10 will not only be unable to accurately detect the angular velocity around the Z axis, but will also detect the angular velocity around the X axis and the angular velocity around the Y axis.

[0056] Therefore, the correction circuit 323 estimates an alignment correction coefficient based on the X-axis angular velocity detection signal SD2GX, the Y-axis angular velocity detection signal SD2GY, and the Z-axis angular velocity detection signal SD2GZ included in the detection signal SD2 acquired by the detection signal acquisition circuit 322, and the Z'-axis angular velocity detection signal SD1GZ' included in the detection signal SD1 acquired by the detection signal acquisition circuit 322. The alignment correction coefficient is a correction coefficient for correcting an error in the Z'-axis angular velocity detection signal SD1GZ' due to a deviation of the Z'-axis with respect to the Z-axis. Then, the correction circuit 323 generates the Z-axis angular velocity detection signal SD1GZ in which the error in the Z'-axis angular velocity detection signal SD1GZ' is corrected based on the estimated alignment correction coefficient. Details of the processing by the correction circuit 323 will be described later.

[0057] The arithmetic circuit 324 executes various calculations on the detection signal SD2 acquired by the detection signal acquisition circuit 322 and the Z-axis angular velocity detection signal SD1GZ generated by the correction circuit 323. For example, the arithmetic circuit 324 performs temperature correction calculations on the X-axis angular velocity detection signal SD2GX, the Y-axis angular velocity detection signal SD2GY, the X-axis acceleration detection signal SD2AX, the Y-axis acceleration detection signal SD2AY, and the Z-axis acceleration detection signal SD2AZ, which are included in the detection signal SD2, and the Z-axis angular velocity detection signal SD1GZ, based on a temperature signal output from a temperature sensor (not shown). In addition, the arithmetic circuit 324 performs sensitivity correction calculations, offset correction calculations, alignment correction calculations, and the like on the X-axis angular velocity detection signal SD2GX, the Y-axis angular velocity detection signal SD2GY, the Z-axis angular velocity detection signal SD1GZ, the X-axis acceleration detection signal SD2AX, the Y-axis acceleration detection signal SD2AY, and the Z-axis acceleration detection signal SD2AZ. The arithmetic circuit 324 may not perform some of the temperature correction calculation, the sensitivity correction calculation, the offset correction calculation, and the alignment correction calculation, or may perform other correction calculations.

[0058] Through this series of calculations, the calculation circuit 324 obtains the X-axis angular velocity measurement data G based on the X-axis angular velocity detection signal SD2GX. X , Y-axis angular velocity measurement data G based on the Y-axis angular velocity detection signal SD2GY Y and Z-axis angular velocity measurement data G based on the Z-axis angular velocity detection signal SD1GZ Z , X-axis acceleration measurement data A based on the X-axis acceleration detection signal SD2AX X , Y-axis acceleration measurement data A based on the Y-axis acceleration detection signal SD2AY Y and Z-axis acceleration measurement data A based on the Z-axis acceleration detection signal SD2AZ Z Generate the X-axis angular velocity measurement data G X , Y-axis angular velocity measurement data G Y , Z-axis angular velocity measurement data G Z , X-axis acceleration measurement data A X , Y-axis acceleration measurement data A Y and Z-axis acceleration measurement data A Z are stored in different registers in the register section 321, respectively.

[0059] When the period for performing a series of calculations is longer than the period of the data ready signals DRDY1 and DRDY2, the calculation circuit 324 performs a downsampling calculation for thinning out a part of the detection signals SD1 and SD2, and then performs various calculation processes.

[0060] Then, when the series of calculations is completed, the calculation circuit 324 outputs a data ready signal DRDY via the terminal THR to the host device 3. When a measurement data read command is input from the host device 3 via the host interface circuit 33, the calculation circuit 324 outputs the measurement data requested by the command to the host device 3 via the host interface circuit 33.

[0061] The host device 3 specifies different addresses to store the X-axis angular velocity measurement data G X , Y-axis angular velocity measurement data G Y , Z-axis angular velocity measurement data G Z , X-axis acceleration measurement data A X , Y-axis acceleration measurement data A Y and Z-axis acceleration measurement data A Z The host device 3 may read out the X-axis angular velocity measurement data G separately, or may read out a plurality of measurement data collectively. The host device 3 may calculate the velocity and attitude of the sensor device 2 based on the read measurement data. Alternatively, the arithmetic circuit 324 may calculate the X-axis angular velocity measurement data G X , Y-axis angular velocity measurement data G Y , Z-axis angular velocity measurement data G Z , X-axis acceleration measurement data A X , Y-axis acceleration measurement data A Y and Z-axis acceleration measurement data A Z Based on this, a calculation may be performed to calculate the attitude and velocity of the sensor device 2. The measurement data of the attitude and velocity of the sensor device 2 are stored in different registers of the register unit 321. As described above, the attitude may be expressed by the roll angle φ, the pitch angle θ, and the yaw angle ψ, or may be expressed by Euler angles or quaternions.

[0062] For example, when the sensor device 2 is attached to the automobile 400, the host device 3 can perform, for example, driving support or automatic driving control of the automobile 400 based on the speed and attitude of the sensor device 2, that is, the speed and attitude of the automobile 400. In the driving support or automatic driving control of the automobile 400, among the roll angle φ, pitch angle θ, and yaw angle ψ representing the attitude of the automobile 400, the yaw angle ψ is the most important. Therefore, it is desirable that the error of the yaw angle ψ is smaller than the errors of the roll angle φ and pitch angle θ. For this reason, the sensor device 2 includes an angular velocity sensor 10 that accurately detects the angular velocity around the Z' axis in order to accurately calculate the yaw angle ψ.

[0063] In particular, due to the bias error Bx [deg / sec] of the X-axis angular velocity detection signal SD2GX, the bias error By [deg / sec] of the Y-axis angular velocity detection signal SD2GY, and the bias error Bz' [deg / sec] of the Z'-axis angular velocity detection signal SD1GZ', the errors of the roll angle φ, pitch angle θ, and yaw angle ψ increase over time. Since the host device 3 can calculate the direction of the gravitational acceleration based on the X-axis acceleration detection signal SD2AX, Y-axis acceleration detection signal SD2AY, and Z-axis acceleration detection signal SD2AZ when the automobile 400 is stopped, the roll angle φ and pitch angle θ can be corrected from the direction of the gravitational acceleration. However, when the automobile 400 is traveling on a substantially horizontal road, since the direction of the Z' axis almost coincides with the direction of the gravitational acceleration, it is extremely difficult for the host device 3 to correct the yaw angle ψ from the direction of the gravitational acceleration. Therefore, it is desirable that the bias error Bz' [deg / sec] of the Z'-axis angular velocity detection signal SD1GZ' is small. Since the sensor device 2 uses the Z'-axis angular velocity detection signal SD1GZ' instead of the Z-axis angular velocity detection signal SD2GZ to generate the Z-axis angular velocity measurement data G Z it is necessary that at least Bz' < Bz, and preferably Bz' < Bz / 2. In this way, by relatively reducing the bias error Bz' of the Z'-axis angular velocity detection signal SD1GZ', the error of the yaw angle ψ can be reduced.

[0064] 1-4. Processing of the correction circuit Next, a specific process will be described in the correction circuit 323. In this embodiment, the correction circuit 323 estimates the alignment correction coefficient by a Kalman filter calculation in which the Z-axis angular velocity detection signal SD2GZ is set as a target value for the Z'-axis angular velocity detection signal SD1GZ'.

[0065] In the following description, the X-axis angular velocity detection signal SD2GX is expressed as ω x,k and the Y-axis angular velocity detection signal SD2GY is ω y,k The Z-axis angular velocity detection signal SD2GZ is ω z,k and the Z'-axis angular velocity detection signal SD1GZ' is Ω z,k Let k represent the time.

[0066] First, as shown in equation (1), ω x,k ,ω y,k ,Ω z,k A 1-by-3 angular velocity matrix X with k is defined.

[0067]

number

[0068] In addition, as shown in equation (2), the estimated alignment correction coefficient c 1,k ,c 2,k ,c 3,k A 3-by-1 correction coefficient matrix Θ with elements k is defined. The correction coefficient matrix Θ k The correction coefficient matrix Θ0, which is the initial value of

[0069]

number

[0070]

number

[0071] The correction circuit 323 executes the prediction step, observation step, and update step of the Kalman filter, and calculates the correction coefficient matrix Θ k 7 shows a flow of processing by the correction circuit 323 using a Kalman filter.

[0072] First, in the prediction step, the correction circuit 323 calculates the correction coefficient matrix Θ updated in the update step at time k-1 according to the formula (4). k From this, Ω at time k z,k Correction value Y' k This correction value Y' k corresponds to the Z-axis angular velocity detection signal SD1GZ obtained by correcting the Z'-axis angular velocity detection signal SD1GZ'.

[0073]

number

[0074] In addition, in the prediction step, the correction circuit 323 calculates the covariance matrix P k From the covariance matrix P' at time k k Predict the covariance matrix P k The covariance matrix P0, which is the initial value of

[0075]

number

[0076]

number

[0077] Next, in the observation step, the correction circuit 323 calculates the expected value Y of the angular velocity around the Z axis as shown in equation (7). k ω x,k Let us assume that.

[0078]

number

[0079] In addition, in the observation step, the correction circuit 323 calculates the variance ρ of the angular velocity around the Z axis as shown in equation (8). k 2 In equation (8), η is the expected value Y of the angular velocity around the Z axis, as shown in equation (9). k and the predicted value Ω at the kth prediction step. z,k Correction value Y' k It is calculated as the difference between

[0080]

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[0081]

number

[0082] Next, in the update step, the correction circuit 323 calculates the angular velocity matrix X k and the covariance matrix P' predicted at the prediction step at time k k and the variance ρ calculated at the observation step at time k k 2 From this, the Kalman gain G at time k+1 is calculated by equation (10). k+1 Calculate.

[0083]

number

[0084] Then, in the update step, the correction circuit 323 calculates the Kalman gain G at time k+1 using equation (11). k+1 and the expected value of the angular velocity around the Z axis at time k, Y k and the angular velocity matrix X at time k k Based on this, the correction coefficient matrix Θ at time k is k Let us use the correction coefficient matrix Θ at time k+1. k+1 In this way, the correction circuit 323 uses the Kalman filter to update the correction coefficient matrix Θ at time k+1.k+1 Estimate.

[0085]

number

[0086] In addition, in the update step, the correction circuit 323 calculates the Kalman gain G at time k+1 using equation (12). k+1 and the angular velocity matrix X at time k k Based on this, the covariance matrix P' predicted at the prediction step for time k is k Let P be the covariance matrix at time k+1. k+1 to update.

[0087]

number

[0088] The correction circuit 323 calculates the correction coefficient matrix Θ at time k+1, which is updated in the update step at time k. k+1 In the prediction step at time k+1, the correction value Y' is calculated using the above formula (4). k+1 Calculate.

[0089] This Kalman filter calculates the expected value of the angular velocity around the Z axis, Y k and the correction value Y' of the angular velocity around the Z' axis k Difference Y k -Y' k =Y k -X k Θ k is controlled so that it approaches zero. As a result, the error in the Z'-axis angular velocity detection signal SD1GZ' caused by the deviation of the Z'-axis from the Z-axis is corrected. In this way, the correction circuit 323 uses a Kalman filter to calculate the correction coefficient matrix Θ k and the correction formula Y', which is the above formula (4), is used. k =X k Θ k Thus, the Z-axis angular velocity detection signal SD1GZ is generated by correcting the Z'-axis angular velocity detection signal SD1GZ'.

[0090] Figure 8 shows thex,k ,ω y,k ,ω z,k ,Ω z,k 9 and 10 show a simulation result of the correction process by the correction circuit 323 using the time series data of FIG. x,k ,ω y,k ,ω z,k ,Ω z,k Alignment correction coefficient c calculated from 1,k ,c 2,k ,c 3,k 10 is a diagram showing time series data of the correction coefficient matrix Θ in FIG. k 10 is a diagram showing time series data of the deviation of the Z-axis angular velocity before and after the correction process using the Z-axis angular velocity deviation Y' k -ω z,k is the deviation of the Z-axis angular velocity before compensation Ω z,k -ω z,k This proves that the correction process by the correction circuit 323 of this embodiment is extremely effective.

[0091] In this embodiment, the inertial sensor 20 is an example of a "first axis angular velocity sensor," and the X-axis angular velocity detection signal SD2GX is an example of a "first angular velocity signal." The inertial sensor 20 is also an example of a "second axis angular velocity sensor," and the Y-axis angular velocity detection signal SD2GY is an example of a "second angular velocity signal." The inertial sensor 20 is also an example of a "third axis angular velocity sensor," and the Z-axis angular velocity detection signal SD2GZ is an example of a "third angular velocity signal." The angular velocity sensor 10 is an example of a "fourth axis angular velocity sensor," and the Z'-axis angular velocity detection signal SD1GZ' is an example of a "fourth angular velocity signal."

[0092] 1-5.Effects As described above, in the sensor device 2 of this embodiment, the X-axis angular velocity sensor, the Y-axis angular velocity sensor, and the Z-axis angular velocity sensor are integrally mounted on the mounting substrate 4 as the inertial sensor 20, so orthogonality of the X-axis, Y-axis, and Z-axis is guaranteed. On the other hand, since the angular velocity sensor 10 is mounted on the mounting substrate 4 separately from the inertial sensor 20, misalignment of the angular velocity sensor 10 with respect to the inertial sensor 20 may occur. In contrast, in the sensor device 2 of this embodiment, the processing device 30 detects the Z-axis angular velocity detection signal SD2GZ, ω z,k and Z'-axis angular velocity detection signal SD1GZ' is Ω z,k Based on this, the Z' axis is offset by Ω z,k Alignment correction coefficient c that corrects the error of 1,k ,c 2,k ,c 3,k Furthermore, the processing device 30 estimates ω x,k , Y-axis angular velocity detection signal SD2GY is ω y,k and Z'-axis angular velocity detection signal SD1GZ' is Ω z,k Based on this, the alignment correction coefficient c, which also takes into account the misalignment of the Z' axis relative to the X and Y axes, is 1,k ,c 2,k ,c 3,k Therefore, according to the sensor device 2 of the present embodiment, the processing device 30 can estimate Ω due to misalignment of the angular velocity sensor 10 with respect to the inertial sensor 20. z,k Alignment correction coefficient c that corrects the error that occurs in 1,k ,c 2,k ,c 3,k In particular, according to the sensor device 2 of the present embodiment, the processing device 30 can estimate ω z,k Ω z,k The target value of the Kalman filter is calculated as Ω due to the deviation of the Z' axis from the Z axis. z,k Alignment correction coefficient c that corrects the error of 1,k ,c 2,k ,c 3,k The processing unit 30 can then efficiently estimate the alignment correction coefficient c 1,k ,c 2,k ,c3,k Using Ω z,k can be accurately corrected.

[0093] In addition, in the sensor device 2 of this embodiment, the processing device 30 calculates the alignment correction coefficient c 1,k ,c 2,k ,c 3,k Estimate Ω z,k Therefore, it is not necessary for the manufacturer of the sensor device 2 to perform an adjustment to accurately align the Z' axis with the Z axis, and the processing device 30 can correct Ω even if the amount of deviation between the Z' axis and the Z axis changes due to aging. z,k can be accurately corrected.

[0094] 2. Variations The present invention is not limited to the present embodiment, and various modifications are possible within the scope of the present invention.

[0095] For example, in the above embodiment, the sensor device 2 includes the angular velocity sensor 10 which is a Z'-axis angular velocity sensor, and the inertial sensor 20 which functions as an X-axis angular velocity sensor, a Y-axis angular velocity sensor, a Z-axis angular velocity sensor, an X-axis acceleration sensor, a Y-axis acceleration sensor, and a Z-axis angular velocity sensor, but may include an X-axis angular velocity sensor, a Y-axis angular velocity sensor, and a Z-axis angular velocity sensor instead of the inertial sensor 20. Also, for example, the sensor device 2 may include an X'-axis angular velocity sensor which detects an angular velocity around the X'-axis corresponding to the X-axis, a Y'-axis angular velocity sensor which detects an angular velocity around the Y'-axis corresponding to the Y-axis, a Z'-axis angular velocity sensor which detects an angular velocity around the Z'-axis corresponding to the Z-axis, and the inertial sensor 20 which functions as an X-axis angular velocity sensor, a Y-axis angular velocity sensor, a Z-axis angular velocity sensor, an X-axis acceleration sensor, a Y-axis acceleration sensor, and a Z-axis angular velocity sensor. Furthermore, for example, the sensor device 2 may include an X'-axis angular velocity sensor, a Y'-axis angular velocity sensor, a Z'-axis angular velocity sensor, an X-axis angular velocity sensor, a Y-axis angular velocity sensor, and a Z-axis angular velocity sensor.

[0096] In the above embodiment, the angular velocity sensor 10 is a quartz sensor with relatively high detection accuracy, and the inertial sensor 20 is a silicon MEMS sensor that is relatively inexpensive, but the types of the angular velocity sensor 10 and the inertial sensor 20 are not limited to this. For example, the angular velocity sensor 10 may be a FOG sensor with relatively high detection accuracy, and the inertial sensor 20 may be a silicon MEMS sensor that is relatively inexpensive. FOG is an abbreviation for Fiber Optic Gyroscope.

[0097] The above-described embodiment and modifications are merely examples, and the present invention is not limited to these. For example, the embodiments and modifications can be appropriately combined.

[0098] The present invention includes configurations that are substantially the same as the configurations described in the embodiments, for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effects. The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects as the configurations described in the embodiments, or configurations that can achieve the same purpose. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments.

[0099] The following can be derived from the above-described embodiment and modifications.

[0100] One aspect of the sensor device is When three mutually orthogonal axes are defined as the first axis, the second axis, and the third axis, a first axis angular velocity sensor that detects an angular velocity about the first axis and outputs a first angular velocity signal; a second axis angular velocity sensor that detects an angular velocity about the second axis and outputs a second angular velocity signal; a third axis angular velocity sensor that detects an angular velocity about the third axis and outputs a third angular velocity signal; a fourth axis angular velocity sensor that detects an angular velocity around a fourth axis corresponding to the third axis and outputs a fourth angular velocity signal; a correction circuit that estimates a correction coefficient for correcting an error in the fourth angular velocity signal due to a deviation of the fourth axis with respect to the third axis, based on the first angular velocity signal, the second angular velocity signal, the third angular velocity signal, and the fourth angular velocity signal; Equipped with.

[0101] In this sensor device, a correction coefficient for correcting an error in the fourth angular velocity signal due to a misalignment of the fourth axis with respect to the third axis can be estimated based on the third angular velocity signal and the fourth angular velocity signal. Furthermore, in this sensor device, a correction coefficient that also takes into account a misalignment of the fourth axis with respect to the first axis and the second axis can be estimated based on the first angular velocity signal, the second angular velocity signal, and the fourth angular velocity signal. Therefore, according to this sensor device, it is possible to accurately estimate a correction coefficient for correcting an error occurring in the fourth angular velocity signal due to a misalignment of the fourth axis angular velocity sensor with respect to the first axis angular velocity sensor, the second axis angular velocity sensor, and the third axis angular velocity sensor.

[0102] In one embodiment of the sensor device, The correction circuit may estimate the correction coefficient by a Kalman filter calculation using the third angular velocity signal as a target value of the fourth angular velocity signal.

[0103] According to this sensor device, a correction coefficient for correcting an error in the fourth angular velocity signal due to a deviation of the fourth axis with respect to the third axis can be efficiently estimated by a Kalman filter calculation in which the third angular velocity signal is used as a target value for the fourth angular velocity signal.

[0104] In one embodiment of the sensor device, The first angular velocity signal is ω x,k and the second angular velocity signal is ω y,k and the fourth angular velocity signal is Ω z,k Then, the angular velocity matrix X k =(ω x,k ,ω y,k ,Ω z,k ) and the correction coefficient is c 1,k ,c 2,k ,c 3,k Then, the correction coefficient matrix Θ k=(c 1,k ,c 2,k ,c 3,k ) T When The correction circuit is a correction formula Y' k =X k Θ k The fourth angular velocity signal may be corrected by:

[0105] According to this sensor device, a correction coefficient that takes into account the deviation of the fourth axis relative to each of the first axis, second axis, and third axis can be estimated, and the error in the fourth angular velocity signal can be accurately corrected using the correction coefficient.

[0106] In one embodiment of the sensor device, the first axis angular velocity sensor, the second axis angular velocity sensor, and the third axis angular velocity sensor are integrally mounted on a mounting substrate; The fourth axis angular velocity sensor may be mounted on the mounting substrate separately from the first axis angular velocity sensor, the second axis angular velocity sensor, and the third axis angular velocity sensor.

[0107] In this sensor device, the first axis angular velocity sensor, the second axis angular velocity sensor, and the third axis angular velocity sensor are integrally mounted on the mounting board, so orthogonality between the first axis, the second axis, and the third axis is guaranteed. Meanwhile, the fourth axis angular velocity sensor is mounted on the mounting board separately from the first axis angular velocity sensor, the second axis angular velocity sensor, and the third axis angular velocity sensor. Therefore, with this sensor device, misalignment of the fourth axis angular velocity sensor with respect to the first axis angular velocity sensor, the second axis angular velocity sensor, and the third axis angular velocity sensor may occur, but a correction coefficient that corrects the error occurring in the fourth angular velocity signal due to this misalignment can be accurately estimated.

[0108] In one embodiment of the sensor device, the first axis angular velocity sensor, the second axis angular velocity sensor, and the third axis angular velocity sensor are mounted on a first surface of the mounting substrate; The fourth axis angular velocity sensor may be mounted on a second surface of the mounting substrate that is opposite to the first surface.

[0109] According to this sensor device, the size of the mounting substrate can be reduced, thereby realizing space saving.

[0110] In one embodiment of the sensor device, When the bias error of the third angular velocity signal is Bz [deg / sec] and the bias error of the fourth angular velocity signal is Bz' [deg / sec], Bz' <Bzであってもよい。

[0111] According to this sensor device, since the bias error of the fourth angular velocity signal is relatively small, it is possible to reduce the error in the angle about the fourth axis obtained by integrating the fourth angular velocity signal. [Explanation of symbols]

[0112] 1...sensor system, 2...sensor device, 3...host device, 4...mounting board, 4a...first surface, 4b...second surface, 5...molding resin, 6...external connection terminal, 10...angular velocity sensor, 11...angular velocity sensor element, 12...processing circuit, 20...inertial sensor, 21X, 21Y, 21Z...angular velocity sensor element, 22X, 22Y, 22Z...acceleration sensor element, 23...processing circuit, 30...processing device, 31...digital interface circuit, 32...processing circuit, 33...host interface circuit, 34...memory, 121...detection circuit, 122...interface circuit, 231...detection circuit, 232...interface circuit, 321...register section, 322...detection signal acquisition circuit, 323...correction circuit, 324...arithmetic circuit, 400...automobile

Claims

1. When three mutually orthogonal axes are defined as the first axis, the second axis, and the third axis, a first axis angular velocity sensor that detects an angular velocity about the first axis and outputs a first angular velocity signal; a second axis angular velocity sensor that detects an angular velocity about the second axis and outputs a second angular velocity signal; a third axis angular velocity sensor that detects an angular velocity about the third axis and outputs a third angular velocity signal; a fourth axis angular velocity sensor that detects an angular velocity about a fourth axis corresponding to the third axis and outputs a fourth angular velocity signal; a correction circuit that estimates a correction coefficient for correcting an error of the fourth angular velocity signal due to a deviation of the fourth axis with respect to the third axis, based on the first angular velocity signal, the second angular velocity signal, the third angular velocity signal, and the fourth angular velocity signal; A sensor device comprising:

2. In claim 1, The correction circuit estimates the correction coefficient by a Kalman filter calculation using the third angular velocity signal as a target value of the fourth angular velocity signal.

3. In claim 2, The first angular velocity signal is ω ｘ，ｋ and the second angular velocity signal is ω ｙ，ｋ and the fourth angular velocity signal is Ω ｚ，ｋ Let us assume that the angular velocity matrix X ｋ = (ω ｘ，ｋ , ω ｙ，ｋ , Ω ｚ，ｋ ) and the correction coefficient is c １，ｋ , c ２，ｋ , c ３，ｋ Then, the correction coefficient matrix Θ ｋ = (c １，ｋ , c ２，ｋ , c ３，ｋ ) Ｔ When The correction circuit is a correction formula Y' ｋ =X ｋ Θ ｋ The sensor device corrects the fourth angular velocity signal by

4. In claim 1, the first axis angular velocity sensor, the second axis angular velocity sensor, and the third axis angular velocity sensor are integrally mounted on a mounting substrate; The fourth axis angular velocity sensor is mounted on the mounting substrate separately from the first axis angular velocity sensor, the second axis angular velocity sensor, and the third axis angular velocity sensor.

5. In claim 4, the first axis angular velocity sensor, the second axis angular velocity sensor, and the third axis angular velocity sensor are mounted on a first surface of the mounting substrate, The fourth axis angular velocity sensor is mounted on a second surface of the mounting substrate, the second surface being opposite to the first surface.

6. In claim 1, The sensor device, wherein when the bias error of the third angular velocity signal is Bz [deg / sec] and the bias error of the fourth angular velocity signal is Bz' [deg / sec], Bz'<Bz.

Images