Inertial measuring device

Abstract

The present disclosure relates to an inertial measurement device that makes it possible to improve the detection accuracy of a multi-IMU system. Four island portions, each island portion having a size resulting from dividing a square opening portion provided upon a substrate into four parts and having one inertial measurement unit (IMU) mounted thereupon, and each of a portion of right-side sections or left-side sections relative to the center of each side of the opening portion are connected by a connection portion that has lower stiffness than the substrate and the island portions. The present invention can be employed in a multi-IMU system.

Description

Technical Field

[0001] The present disclosure relates to an inertial measurement device, and particularly to an inertial measurement device configured to improve the detection accuracy of a multi-IMU system. Background Art

[0002] A multi-IMU system configured to improve detection accuracy by integrating detection results from a plurality of IMUs (Inertial Measurement Units) has been proposed.

[0003] As a technique for improving the detection accuracy of a multi-IMU system, there has been proposed a technique that enables appropriate combining of observation values from a plurality of IMUs in accordance with the noise characteristics of the plurality of IMUs and conditions for the observation values (see Patent Document 1). Prior Art Documents Patent Documents

[0004] Patent Document 1 International Publication No. 2020 / 045099 Summary of the Invention Problem to be Solved by the Invention

[0005] Incidentally, in a vibration-type IMU using MEMS (Micro Electro Mechanical Systems) that is used in multi-IMU systems including the example disclosed in Patent Document 1, angular velocity is detected based on Coriolis force generated when an object is rotated while vibration is applied thereto.

[0006] However, since a plurality of IMUs each generate vibration, for each IMU, interference occurs due to the vibration generated by other IMUs, which may result in beat noise caused by such interference.

[0007] In particular, due to the recent improvements in manufacturing precision of IMUs, production variations have decreased, and since a large number of IMUs are manufactured with similar vibration frequencies, interference is more likely to occur, making them more susceptible to interference-induced hum noise.

[0008] This disclosure has been made in view of the above circumstances, and in particular aims to reduce the effects of beat noise caused by interference between individual IMUs constituting a multi-IMU, thereby realizing a high-precision multi-IMU. [Means for solving the problem]

[0009] An inertial measuring device according to one aspect of this disclosure comprises a predetermined number of mounting sections on which one IMU (Inertial Measurement Unit) is mounted, and a predetermined number of connecting sections that connect one of the mounting sections to the edge of an opening provided in a substrate, wherein the connecting section has lower rigidity than the substrate.

[0010] In one aspect of this disclosure, a predetermined number of mounting sections, each mounting an IMU (Inertial Measurement Unit), are connected to the edge of an opening provided in a substrate by a predetermined number of connection sections, wherein the connection sections have lower rigidity than the substrate. [Brief explanation of the drawing]

[0011] [Figure 1] This is a diagram illustrating the multi-IMU (Infrared Measure Unit) concept. [Figure 2] This is a diagram illustrating the structure of an IMU. [Figure 3] This diagram illustrates the circuit configuration of the IMU readout circuit shown in Figure 2. [Figure 4] Figure 2 is a diagram illustrating the operation of the IMU. [Figure 5] This diagram illustrates the operation of a multi-IMU. [Figure 6] This diagram illustrates interference caused by multiple IMUs. [Figure 7] This diagram illustrates interference caused by multiple IMUs. [Figure 8] It is a diagram explaining interference caused by multiple IMUs. [Figure 9] It is a diagram explaining a method for suppressing interference caused by multiple IMUs. [Figure 10] It is a diagram explaining the first embodiment of the multiple IMUs of the present disclosure. [Figure 11] It is a diagram explaining the structure that suppresses beating in the multiple IMUs of FIG. 10. [Figure 12] It is a diagram explaining a first modification of the first embodiment of the multiple IMUs of the present disclosure. [Figure 13] It is a diagram explaining a second modification of the first embodiment of the multiple IMUs of the present disclosure. [Figure 14] It is a diagram explaining a third modification of the first embodiment of the multiple IMUs of the present disclosure. [Figure 15] It is a diagram explaining a first example of the second embodiment of the multiple IMUs of the present disclosure. [Figure 16] It is a diagram explaining a second example of the second embodiment of the multiple IMUs of the present disclosure. [Figure 17] It is a diagram explaining a third example of the second embodiment of the multiple IMUs of the present disclosure. [Figure 18] It is a diagram explaining a fourth example of the second embodiment of the multiple IMUs of the present disclosure. [Figure 19] It is a diagram explaining a first example of the third embodiment of the multiple IMUs of the present disclosure. [Figure 20] It is a diagram explaining a second example of the third embodiment of the multiple IMUs of the present disclosure. [Figure 21] It is a diagram explaining the fourth embodiment of the multiple IMUs of the present disclosure. [Figure 22] It is a diagram explaining the fourth embodiment of the multiple IMUs of the present disclosure. [Figure 23] It is a diagram explaining the fifth embodiment of the multiple IMUs of the present disclosure. [Figure 24] It is a diagram explaining the sixth embodiment of the multiple IMUs of the present disclosure. [Figure 25] This figure illustrates a seventh embodiment of the multi-IMU of the present disclosure. [Figure 26] This figure illustrates an eighth embodiment of the multi-IMU of the present disclosure. [Modes for carrying out the invention]

[0012] Preferred embodiments of this disclosure will be described in detail below with reference to the attached drawings. In this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant descriptions will be omitted.

[0013] The following describes the configurations for implementing this technology. The explanation will proceed in the following order. 1. Summary of this disclosure 2. First Embodiment 3. Second Embodiment 4. Third Embodiment 5. Fourth Embodiment 6. Fifth Embodiment 7. Sixth Embodiment 8. Seventh Embodiment 9. Eighth Embodiment

[0014] <<1. Summary of this Disclosure>> <About Multi-IMU> This disclosure, in particular, reduces the effects of beat noise caused by interference between individual IMUs constituting a multi-IMU (Inertial Measurement Unit), thereby realizing a high-precision multi-IMU.

[0015] First, in order to explain the overview of this disclosure, we will explain multi-IMU.

[0016] As shown in the left part of FIG. 1, a single IMU 1 includes, for example, an acceleration sensor that detects acceleration, which is translational motion, in each of the three axis directions consisting of XYZ axes, and a gyro sensor that detects angular velocity, which is rotational motion, and detects acceleration and angular velocity in each of the three axis directions.

[0017] Although high-precision single IMU 1 exists, generally higher-precision IMUs are larger and more expensive: aiming for higher precision leads to an increase in size and an increase in cost.

[0018] Therefore, as shown in the right part of FIG. 1, a plurality (for example, n pieces) of low-precision but low-cost IMUs 1 are provided as IMU 1-1 to 1-n, and a combiner 2 combines the acceleration and angular velocity, which are the detection results of each of IMU 1-1 to 1-n, thereby reducing noise density and bias fluctuation to 1 / √n, improving detection accuracy, and achieving higher precision. This configuration is the multi-IMU 10.

[0019] The device size and device cost of each low-precision and low-cost IMU 1-1 to 1-n constituting the multi-IMU 10 shown in the right part of FIG. 1 can be sufficiently reduced compared to the device size and device cost when a single high-precision IMU 1 as shown in the left part of FIG. 1 is prepared, and cost reduction can be realized.

[0020] Hereinafter, when there is no particular need to distinguish between IMU 1-1 to 1-n, they will be simply referred to as IMU 1, and other components will be referred to in the same manner. In addition, in the present specification, hereinafter, IMU 1 is assumed to be a small, low-cost IMU with relatively low accuracy, but it may also be a large, expensive, high-precision IMU.

[0021] <Structure of IMU> Next, the structure of IMU 1 will be described with reference to FIG. 2.

[0022] Each IMU 1 constituting the multi-IMU 10 consists of, as shown in the right side of Figure 2, a silicon oscillator 11, a base 12 that fixes the oscillator 11, and a readout circuit 13 that reads the vibration of the oscillator 11 and outputs the angular velocity. These components are bonded together in the order shown in the right side of Figure 2 and integrated by resin molding as shown in the left side of Figure 2.

[0023] <Circuit configuration of the readout circuit> Next, with reference to Figure 3, the circuit configuration of the read circuit 13 for the IMU 1 will be described.

[0024] Furthermore, Figure 3 will describe the configuration for detecting angular velocity among the readout circuits that make up IMU1. The configuration for detecting acceleration in IMU1 is the same as the configuration for detecting angular velocity, but without the detection circuit. Therefore, we will focus on describing the more complex configuration for detecting angular velocity.

[0025] The readout circuit 13 consists of a drive circuit block 31, a sense circuit block 32, and a digital output circuit block 33.

[0026] The drive circuit block 31 supplies an oscillation signal consisting of a predetermined drive frequency to the oscillator 11 and sense circuit block 32, which are made of MEMS (Micro Electro Mechanical Systems), causing the oscillator 11 to vibrate based on the oscillation signal.

[0027] The sense circuit block 32 detects the vibrations generated in response to the Coriolis force acting on the oscillator 11, which vibrates based on the oscillation signal, as an analog signal and outputs it to the digital output circuit block 33.

[0028] The digital output circuit block 33 converts the vibrations generated in response to the Coriolis force acting on the oscillator 11, supplied by the sense circuit block 32, from an analog signal to a digital signal and outputs it as angular velocity.

[0029] More specifically, the drive circuit block 31 includes an oscillator circuit 51 and an automatic gain adjustment circuit 52.

[0030] The oscillation circuit 51 is composed of RC components and generates an oscillation signal using the vibration supplied from the oscillator 11 as a reference signal, which is then output to the automatic gain adjustment circuit 52 and the phase shift circuit 72 of the sense circuit block 32.

[0031] The automatic gain adjustment circuit 52 adjusts the gain of the oscillation signal consisting of the drive frequency supplied from the oscillation circuit 51 and supplies it to the oscillator 11, causing the oscillator 11 to vibrate.

[0032] The sense circuit block 32 includes a charge amplifier circuit 71, a phase shift circuit 72, a synchronous detection circuit 73, and an LPF 74.

[0033] The charge amplifier circuit 71 detects the vibration of the oscillator 11 as a vibration signal, amplifies it, and supplies it to the phase shift circuit 72.

[0034] The phase shift circuit 72 adjusts the phase of the vibration signal of the oscillator 11 detected by the charge amplifier circuit 71 based on the oscillation signal supplied from the oscillation circuit 51, and outputs it to the synchronous detection circuit 73.

[0035] The synchronous detection circuit 73 detects a waveform representing the Coriolis force acting on the oscillator 11, expressed as an envelope, from the phase-adjusted oscillation signal of the oscillator 11, and outputs it to the LPF 74.

[0036] The LPF74 smooths the waveform representing the Coriolis force acting on the oscillator 11 and outputs it to the digital output circuit block 33 as angular velocity information consisting of an analog signal.

[0037] The digital output circuit block 33 includes an AD conversion circuit 91, a decimation filter 92, and a digital output circuit 93.

[0038] The AD conversion circuit 91 converts angular velocity information, which is derived from the Coriolis force acting on the vibrator 11 and is in the form of an analog signal, into a digital signal and outputs the digital signal to the decimation filter 92.

[0039] The decimation filter 92 averages the angular velocity information in the form of a digital signal and outputs the averaged information to the digital output circuit 93.

[0040] The digital output circuit 93 outputs the digitized and averaged angular velocity information as a digital signal.

[0041] <Operation of IMU> Next, the operation of the IMU 1 will be described with reference to FIG. 4.

[0042] As shown in the upper left part of FIG. 4, the vibrator 11 oscillates based on a reference signal formed of an oscillation signal of drive frequency fb oscillated by the oscillation circuit 51 and gain-adjusted by the automatic gain adjustment circuit 52.

[0043] At this time, when Coriolis force acts on the vibrator 11, amplitude modulation by the Coriolis force is applied, so that, for example, the waveform output from the charge amplifier circuit 71 undergoes amplitude modulation corresponding to the Coriolis force with respect to the drive frequency fb, as shown by the waveform fbc.

[0044] The synchronous detection circuit 73 detects the amplitude modulation caused by the Coriolis force from the envelope of the waveform fbc as an analog signal waveform indicating the Coriolis force, that is, the angular velocity, and outputs the detected waveform to the LPF 74.

[0045] The waveform of the analog signal extracted as Coriolis force in this manner is converted into a digital signal by the digital output circuit block 33 and output as a digitized angular velocity value.

[0046] The multi-IMU combines n IMU1 units, as shown in Figure 5, and outputs the angular velocities detected by each of the IMU1-1 to 1-n units by combining them with a synthesizer 2 to improve accuracy.

[0047] <Interference caused by multiple IMUs> The multi-IMU 10 is specifically configured as shown in Figure 6, for example.

[0048] In other words, the multi-IMU 10 in Figure 6 is configured such that IMUs 1-1 to 1-4 are provided on the printed circuit board 110.

[0049] With this configuration, in the multi-IMU10 shown in Figure 6, the angular velocities detected by each of IMU1-1 to IMU1-4 are combined, resulting in improved detection accuracy and output.

[0050] Incidentally, it is known that due to manufacturing variations, the drive frequency of IMU1 can vary by, for example, about 3%.

[0051] Therefore, if IMU1 is designed to have a drive frequency of 20.000kHz, the configuration may be as shown in Figure 6, IMU1-1 to IMU1-4, where IMU1-1 is driven at 20.000kHz, IMU1-2 is driven at 20.010kHz, IMU1-3 is driven at 19.900kHz, and IMU1-1 is driven at 20.020kHz.

[0052] In such a case, the small frequency difference between the driving frequencies of IMU1-1 to IMU1-4 causes interference between them in the vibration of the oscillator 11.

[0053] More specifically, as shown in Figure 7, for example, a reference signal consisting of an oscillation signal with a drive frequency fb output via an automatic gain adjustment circuit 52 in a predetermined IMU1 is affected by interference from a reference signal consisting of a drive frequency fb' (≠fb) of another nearby IMU1, which is a disturbance (acoustic vibration). As a result, amplitude modulation occurs in the reference signal actually supplied to the oscillator 11, and it is supplied to the oscillator 11 as an amplitude-modulated signal fe that includes beats corresponding to the frequency difference.

[0054] Consequently, if a reference signal consisting of a drive frequency fb is supplied to the oscillator 11, the waveform fc shown in Figure 7 is detected as the angular velocity. However, if the reference signal supplied to the oscillator 11 changes to an amplitude-modulated signal fe due to a disturbance, the angular velocity will be detected as an amplitude-modulated signal, shown by the thick line in the figure, instead of the waveform fc that would normally be detected as the angular velocity. This results in an error in the angular velocity.

[0055] Similarly, beats occur as oscillations of frequencies corresponding to the frequency differences between each of the IMU1-1 through IMU1-4.

[0056] In other words, as shown in Figure 8, the beat frequency between IMU1-1 and IMU1-2 is 10 Hz, which is the difference between their drive frequencies; the beat frequency between IMU1-1 and IMU1-3 is 100 Hz, which is the difference between their drive frequencies; and the beat frequency between IMU1-1 and IMU1-3 is 20 Hz, which is the difference between their drive frequencies.

[0057] Furthermore, the beat frequency between IMU1-2 and IMU1-3 is 110Hz, which is the difference between their drive frequencies; the beat frequency between IMU1-2 and IMU1-4 is 10Hz, which is the difference between their drive frequencies; and the beat frequency between IMU1-3 and IMU1-4 is 120Hz, which is the difference between their drive frequencies.

[0058] As a result, IMU1-1 through IMU1-4 each have error oscillations in their undulation frequencies superimposed due to interference from each other's reference signals. Consequently, IMU1-1 through IMU1-4 detect angular velocities that include errors, and there was a risk that combining these would not yield an accurate angular velocity.

[0059] Therefore, as shown in the multi-IMU110 in Figure 9, for example, it is conceivable to suppress the generation of beats by selecting four IMUs 1-11 to 1-14, each with completely different drive frequencies.

[0060] In Figure 9, the driving frequencies of IMUs 1-11 to 1-14 are set to 25kHz, 20kHz, 15kHz, and 30kHz, respectively.

[0061] By having IMUs 1-11 through 1-14 each operate at completely different frequencies, the generation of hum is suppressed.

[0062] However, configuring a multi-IMU110 requires manufacturing IMU1 with at least four different drive frequencies, which increases manufacturing costs and limits the number of drive frequency variations that can be combined.

[0063] <<2. First Embodiment>> <Example of the multi-IMU structure of this disclosure> Therefore, in the multi-IMU of this disclosure, by devising the shape of the substrate and arranging each of the multiple IMUs constituting the multi-IMU in an island structure, interference caused by mutual vibration is suppressed, and the generation of hum noise caused by interference is suppressed.

[0064] In other words, in the multi-IMU 200 of this disclosure shown in Figure 10, IMUs 201-1 to 201-4 are arranged on a printed circuit board 210.

[0065] Here, the printed circuit board 210 and IMUs 201-1 to 201-4 in the multi-IMU 200 of Figure 10 correspond to the printed circuit board 110 and IMUs 1-1 to 1-4 in the IMU 10 of Figure 6, respectively. Furthermore, the number of IMUs 201 placed on the printed circuit board 210 is not limited to the four IMUs 201-1 to 201-4 shown in Figure 10, but may be any other number.

[0066] Furthermore, on the printed circuit board 210 of the multi-IMU200 shown in Figure 10, in addition to IMU201-1 to 201-4, a control IC (Integrated Circuit) 202 that controls the multi-IMU200 and synthesizes and outputs the detection results of IMU201-1 to 201-4, and a connector 203 that electrically connects the multi-IMU200 to external equipment are arranged.

[0067] Furthermore, the printed circuit board 210 of the multi-IMU 200 in Figure 10 is provided with screw holes 204-1 and 204-2 for joining the multi-IMU 200 to another circuit board or the like (not shown) using screws or the like.

[0068] IMUs 201-1 to 201-4 are provided in each of the island-like structures 221-1 to 221-4 located on the right side of the printed circuit board 210 in the figure. Note that in the right side of Figure 10, one island-like structure 221 is shown separately.

[0069] The island-like structures 221-1 to 221-4 are structures located within the rectangular area indicated by the dashed-dotted line in the figure, and are formed in the respective areas obtained by dividing the roughly square opening 211 provided in the printed circuit board 210, which is represented by the white area in the figure, into roughly four sections.

[0070] As shown in the right side of Figure 10, each individual island-shaped structure 221 consists of an island portion 221a and a connecting portion 221b, with the IMU 201 positioned on the island portion 221a. In other words, the island portion 221a functions as a mounting portion for the IMU 201. The shape and size of each island portion 221a are approximately 1 / 4 the shape and size of the opening 211. In other words, the island portions 221a-1 to 221a-4 are contained within the opening 211.

[0071] The spacing between adjacent island portions 221a is set to a distance that prevents them from coming into contact with each other due to thermal expansion of the material, etc. Similarly, the spacing between each island portion 221a and each side of the opening 211 (the edge of the opening 211) is also set to a distance that prevents them from coming into contact with each other due to thermal expansion of the material, etc. It should be noted that, after the rectangular opening 211 is formed on the substrate 210, the island portions 221a are not connected to the edge of the opening 211 via connecting portions 221b. Rather, the island portions 221a and connecting portions 221b are formed by cutting the white areas within the opening 211 in Figure 10 into a slit shape using a rotary tool. Therefore, the spacing between adjacent island portions 221a is approximately the size of the outer diameter of the rotary tool used to excavate the substrate 210.

[0072] The connecting portion 221b connects a part of the right side of each side (edge) that constitutes the roughly square opening 211, which is represented by the white outline in the figure, to a part of the island portion 221a, when viewed from the outer periphery. This connects the island portion 221a to the printed circuit board 210.

[0073] With this configuration, when viewed in a clockwise order in the figure, the island-like structures 221-1 to 221-4 are arranged in a way that rotates their respective orientations clockwise by 90 degrees each.

[0074] Furthermore, the clockwise order of the island-like structures 221-1 to 221-4 referred to here specifically means that, starting from island-like structure 221-1, the order is island-like structure 221-1, island-like structure 221-2, island-like structure 221-4, and island-like structure 221-3.

[0075] Specifically, island-shaped structure 221-1 is positioned such that the connecting portion 221b-1 faces upward in the figure, island-shaped structure 221-2 is positioned such that the connecting portion 221b-2 faces to the right in the figure, island-shaped structure 221-4 is positioned such that the connecting portion 221b-4 faces downward in the figure, and island-shaped structure 221-3 is positioned such that the connecting portion 221b-3 faces to the left in the figure.

[0076] Furthermore, the connection portion 221b may be configured such that, when the roughly square opening 211, represented by the white outline in the figure, is viewed from the outer periphery, the island portion 221a is connected to the portion to the left of the center of each side constituting the opening 211, thereby connecting the island portion 221a to the printed circuit board 210.

[0077] The connection section 221b is provided with wiring (not shown) connected to the IMU 201 installed on the island section 221a, thereby physically connecting the IMU 201 and the printed circuit board 210, as well as electrically connecting them.

[0078] The connection portion 221b is configured to have lower rigidity than the island portion 221a, making it difficult for vibrations in the printed circuit board 210 to be transmitted to the island portion 221a. More specifically, the width Wg of the connection portion 221b is smaller than the width Wi of the island portion 221a, resulting in a narrow structure, which means that the rigidity of the connection portion 221b is lower than that of the island portion 221a. With this configuration, even if the connection portion 221b and the island portion 221a are made of the same material, the rigidity of the connection portion 221b is lower than that of the island portion 221a. Furthermore, because the connection portion 221b is smaller than the printed circuit board 210, the rigidity of the connection portion 221b is lower than that of the printed circuit board 210.

[0079] In other words, since a connection portion 221b with lower rigidity than the rigidity of both is formed between each island portion 221a and the printed circuit board 210, the drive vibrations between IMUs 201-1 to 201-4 are less likely to propagate through the printed circuit board 210. As a result, interference of drive vibrations between IMUs 201-1 to 201-4 can be suppressed, and consequently, the generation of hum noise caused by interference can be suppressed.

[0080] The width Wi of the connection portion 221b is set to the minimum necessary to form the wiring connected to the IMU 201, thereby further reducing the rigidity of the connection portion 221b and making it more difficult for drive vibrations of IMUs 201-1 to 201-4 transmitted via the printed circuit board 210 to be transmitted to the island portion 221a.

[0081] In other words, by making the width Wi of the connection part 221b narrower, the rigidity can be reduced, making it more difficult for drive vibrations to propagate between IMUs 201-1 to 201-4. As a result, interference between IMUs 201-1 to 201-4 is suppressed, and the generation of hum noise can be suppressed.

[0082] Furthermore, as shown in Figure 11, among the island-shaped structures 221-1 to 221-4, the island-shaped structures 221 that are subjected to drive vibrations transmitted via the printed circuit board 210 from the same direction are structured such that connection portions 221b are provided at positions separated from each other.

[0083] Due to this structure, the propagation of drive vibrations in the same direction is difficult, interference is suppressed, and the generation of hum noise can be reduced.

[0084] More specifically, as shown in Figure 11, of the island-like structures 221-1 to 221-4, the island portions 221a-1 and 221a-4 of island-like structures 221-1 and 221a-4 are connected to the printed circuit board 210 via connecting portions 221b-1 and 221b-4, respectively. Vibrations from the printed circuit board 210 are easily transmitted to the island portions 221a-1 and 221a-4 via connecting portions 221b-1 and 221b-4, respectively, in the direction of arrow DV in the figure.

[0085] For example, if the connection points 221b-1 and 221b-4 are positioned so that they are close together, vibrations from both will propagate more easily, resulting in interference between IMUs 201-1 and 201-4 and causing hum noise.

[0086] In contrast, in the multi-IMU 200 of this disclosure, as shown in Figure 11, the two connection parts 221b-1 and 221b-4 are located on opposite sides of the substantially square opening 211, and are positioned symmetrically with respect to the center of the opening 211, and are arranged at separate locations on the printed circuit board 210 that transmits vibrations.

[0087] Vibrations are attenuated more as the distance they travel increases, but as mentioned above, the distance between the connection parts 221b-1 and 221b-4 is large, and they are located far apart within the printed circuit board 210, so the structure makes it difficult for vibrations to propagate between the connection parts 221b-1 and 221b-4.

[0088] In other words, this structure makes it possible to suppress interference between IMU201-1 and 201-4, thereby suppressing the generation of beat noise caused by interference.

[0089] Furthermore, as shown in Figure 11, among the island-like structures 221-1 to 221-4, the island portions 221a-2 and 221a-3 of island-like structures 221-2 and 221-3 are connected to the printed circuit board 210 via connecting portions 221b-2 and 221b-3, respectively. Vibrations from the printed circuit board 210 are easily transmitted to the island portions 221a-2 and 221a-3 in the direction of arrow DV in the figure via connecting portions 221b-2 and 221b-3, respectively.

[0090] Similarly to connection parts 221b-1 and 221b-4, as shown in Figure 11 and indicated by the dotted arrows, both connection parts 221b-2 and 221b-3 are located on opposite sides of the roughly square opening 211, in a point-symmetrical position with respect to the center of the opening 211, and are positioned at separate locations on the printed circuit board 210 that transmits vibrations.

[0091] In other words, this structure makes it possible to suppress interference between IMU201-2 and 201-3, just as it does between IMU201-1 and 201-4, thereby suppressing the generation of beat noise caused by interference.

[0092] Figure 11 shows only the area of ​​the multi-IMU 200 in Figure 10 where the island-shaped structures 221-1 to 221-4, enclosed by the rectangular dotted lines in Figure 10, are located. Hereafter, this area where the island-shaped structures 221-1 to 221-4 are located will simply be referred to as the IMU placement unit 200U.

[0093] Furthermore, while the above describes an example where the opening 211 is approximately square and the island portion 211a is approximately 1 / 4 the size and shape of the opening 211, the shape does not necessarily have to be square or rectangular. It is sufficient to form an island portion 211a that can be contained within the opening 211 and on which the IMU 201 can be mounted.

[0094] For this reason, for example, multiple round island portions 211a may be formed within the rectangular opening 211, each of a size that allows the IMU 201 to be mounted and can be contained within the opening 211 in terms of arrangement, or the island portions 211a may be of other shapes.

[0095] However, the greater the physical distance between the connecting parts 211b that connect each island portion 211a and the edge of the opening 211, the more the vibrations propagating in the printed circuit board 210 between them are attenuated, interference is suppressed, and the effect of reducing hum noise caused by interference is enhanced. Therefore, it is desirable to arrange the connecting parts 211b so that they are further apart.

[0096] <Example 1> In the above, we have described an example configuration of a multi-IMU200 consisting of four IMU201 units. However, the number of IMU201 units may be greater than this. For example, for a multi-IMU200 consisting of eight IMU201 units, the configuration may be as shown in Figure 12, with two IMU placement units 200U as shown in Figure 11 arranged side by side.

[0097] In Figure 12, an example is shown in which the IMU placement units 200U-1 and 200U-2 are arranged side by side in the vertical direction shown in the figure. Needless to say, they may also be arranged side by side horizontally, or two or more units may be arranged side by side.

[0098] In this configuration as well, it is possible to suppress interference of drive vibrations between multiple IMU201s and to suppress the generation of hum noise caused by interference.

[0099] <Modification 2> Furthermore, for example, in the case of a multi-IMU200 in which IMU201 is configured in units of 16, the IMU arrangement unit 200U shown in Figure 11 may be arranged in a configuration where two units are placed side by side in the horizontal and vertical directions, as shown in Figure 13.

[0100] Furthermore, Figure 13 shows an example in which two IMU placement units 200U are arranged side by side in the horizontal and vertical directions, respectively, as indicated by IMU placement units 200U-11 to 200U-14 in the figure.

[0101] In this configuration as well, it is possible to suppress interference of drive vibrations between multiple IMU201s and to suppress the generation of hum noise caused by interference.

[0102] Furthermore, even in configurations where many more IMU placement units 200U are arranged in a row horizontally and vertically, it is possible to similarly suppress the generation of hum noise.

[0103] <Variation 3> In the above, we have described an example in which the connecting portion 221b connects a portion of the right side of each side (each edge) constituting the roughly square opening 211, which is represented by the white outline in the figure, to a portion of the island portion 221a when viewed from the outer periphery. However, the connecting portion 221b may also be provided at the corner of the opening 211.

[0104] Figure 14 shows an example configuration of the multi-IMU 200 in which the connection portion 221b is provided at each of the four corners of the opening 211.

[0105] In the multi-IMU200 shown in Figure 14, components with the same functionality as those in the multi-IMU200 shown in Figure 11 are denoted by the same reference numerals, and their explanations are omitted as appropriate.

[0106] In other words, the difference between the multi-IMU 200 in Figure 14 and the multi-IMU 200 in Figure 11 is that island-like structures 221'-1 to 221'-4 are provided instead of island-like structures 221'-1 to 221'-4.

[0107] The island-like structures 221'-1 to 221'-4 are basically the same as the island-like structures 221'-1 to 221'-4, each equipped with IMUs 201'-1 to 201'-4, and their basic functions are identical, but their structures differ.

[0108] In other words, each island-like structure 221'-1 to 221'-4 is composed of island sections 221'a-1 to 221'a-4 and connecting sections 221'b-1 to 221'b-4.

[0109] The connecting portions 221'b-1 to 221'b-4 each connect the printed circuit board 210 to the corners of the island portions 221'a-1 to 221'a-4 via the four corners of the opening 211.

[0110] As shown in Figure 14, among the island-shaped structures 221'-1 to 221'-4, the island-shaped structures 221' that are easily subjected to vibrations propagated from the printed circuit board 210 from the same direction are connected by connection parts 221'b at positions far apart from each other. This makes it difficult for vibrations to propagate from each other in the same direction, thereby suppressing vibration interference and thus suppressing the generation of hum noise caused by interference.

[0111] More specifically, as shown in Figure 14, of the island-like structures 221'-1 to 221'-4, the island portions 221'a-1 and 221'a-4 of island-like structures 221'-1 and 221'a-4 are connected to the printed circuit board 210 via connecting portions 221'b-1 and 221'b-4, respectively. The island portions 221'a-1 and 221'a-4 are structured in such a way that vibrations from the printed circuit board 210 are easily transmitted to them in the direction of arrow D1 in the figure via connecting portions 221'b-1 and 221'b-4, respectively.

[0112] For example, if the connection points 221'b-1 and 221'b-4 are positioned so that they are close to each other, vibrations from both will propagate more easily, resulting in interference between IMUs 201-1 and 201-4, which in turn causes hum noise.

[0113] In contrast, in the multi-IMU 200 of this disclosure, as shown in Figure 14, the two connection points 221'b-1 and 221'b-4 are arranged on the diagonal of the opening 211, as indicated by the dashed arrows, and are positioned at the furthest possible locations on the opening 211 in the printed circuit board 210 that transmits vibrations.

[0114] Therefore, the island-like structures 221'-1 and 221'-4 are designed to make it difficult for vibrations to propagate, thereby suppressing interference caused by vibrations between IMUs 201-1 and 201-4, and thus suppressing the generation of hum noise caused by interference.

[0115] Similarly, as shown in Figure 14, among the island-like structures 221'-1 to 221'-4, the island portions 221'a-2 and 221'a-3 of island-like structures 221'-2 and 221'a-3 are connected to the printed circuit board 210 via connecting portions 221'b-2 and 221'b-3, respectively, and the island portions 221'a-2 and 221'a-3 are structured in such a way that vibrations from the printed circuit board 210 can easily propagate in the direction of arrow D2 in the figure via connecting portions 221'b-2 and 221'b-3, respectively.

[0116] In other words, similar to connection parts 221'b-1 and 221'b-4, as indicated by the dotted arrows in Figure 14, both connection parts 221'b-2 and 221'b-3 are positioned diagonally across the opening 211, and are structured to be located at the furthest positions on the opening 211 in the printed circuit board 210 that transmits vibrations.

[0117] Therefore, the structure is designed to prevent vibration propagation between the island-like structures 221'-2 and 221'-3, thereby suppressing interference caused by vibrations between IMUs 201-2 and 201-3, and preventing the generation of hum noise caused by interference.

[0118] Furthermore, the IMU placement unit 200U shown in Figure 14 can also be arranged as shown in Figures 12 and 13, and the same effect can be achieved by using not only 4 IMUs 201, but also 8, 16, or other numbers.

[0119] <<3. Second Embodiment>> <Part 1> In the above, we have described an example of the configuration of a multi-IMU 200 which is composed of four island-shaped structures 221 as a unit. However, it may also be configured with other numbers of units, for example, it may be configured with two island-shaped structures 221 as a unit.

[0120] Figure 15 shows an example of the configuration of a multi-IMU 200, which is composed of two island-like structures 221 as units.

[0121] The multi-IMU 200 in Figure 15 is composed of island-like structures 221-11 and 221-12, with island sections 221a-11 and 221a-12 adjacent to each other, and connecting sections 221b-11 and 221b-12 provided on a part of the opposite side of the opening 211, sandwiching island sections 221a-11 and 221a-12. In the multi-IMU 200 in Figure 15, the opening 211 is configured as a rectangular shape that is elongated horizontally in the figure.

[0122] Thus, in the multi-IMU 200 shown in Figure 15, the two connection points 221b-11 and 221b-12 are positioned on the short sides that form opposite sides of the opening 211, and are structured to be located at the furthest possible positions within the opening 211 of the printed circuit board 210 that transmits vibrations.

[0123] Therefore, the island-like structures 221-11 and 221-12 are designed to make it difficult for vibrations to propagate, thereby suppressing interference caused by vibrations between IMUs 201-11 and 201-12, and thus suppressing the generation of hum noise caused by interference.

[0124] Furthermore, IMU placement units 200UA, each consisting of a multi-IMU 200 as shown in Figure 15, may be arranged adjacently in the horizontal and vertical directions to form a multi-IMU 200 consisting of two or more island-like structures 221.

[0125] <Part 2> In the above, we have described an example configuration in which two island-shaped structural units 221 are used as a unit, with two island sections 221a adjacent to each other horizontally, and two connecting sections 221b provided on a part of the short side opposite the opening 211, sandwiching the two island sections 221a.

[0126] However, the two connecting portions 221b may be provided on the long sides opposite each other of the opening 211, in a positional relationship that is point-symmetrical with respect to the center position.

[0127] Figure 16 shows an example of the configuration of a multi-IMU 200, which is composed of two island-like structural units 221, in which the two connecting parts 221b are located on the long sides opposite each other of the opening 211, and are positioned in a point-symmetrical relationship with respect to the center position.

[0128] In other words, the multi-IMU 200 in Figure 16 is composed of island-like structures 221-21 and 221-22, with island sections 221a-21 and 221a-22 adjacent to each other, and connecting sections 221b-21 and 221b-22 provided on the opposing long sides of the opening 211 at point-symmetrical positions with respect to the center position.

[0129] Thus, in the multi-IMU 200 shown in Figure 16, the two connection points 221b-21 and 221b-22 are located on the opposing long sides of the opening 211, in a point-symmetrical position with respect to the center position, and are positioned at separate locations on the printed circuit board 210 that transmits vibrations.

[0130] Therefore, the island-like structures 221-21 and 221-22 are designed to make it difficult for vibrations to propagate, thereby suppressing vibration interference between IMUs 201-21 and 201-22, and making it possible to suppress the generation of hum noise caused by interference.

[0131] Furthermore, IMU placement units 200UB, each consisting of the multi-IMU 200 shown in Figure 16, may be arranged adjacently in the horizontal and vertical directions to form a multi-IMU 200 consisting of two or more island-shaped structural units 221.

[0132] <Part 3> In the above, we have described an example in which two island-like structural parts 221 are used as a unit, and the two connecting parts 221b are provided on the long sides opposite each other of the rectangular opening 211, in a positional relationship that is point-symmetric with respect to the center position.

[0133] However, the two connecting portions 221b may be provided in such a positional relationship that they are located on adjacent sides (edges) of the rectangular opening 211.

[0134] Figure 17 shows an example of the configuration of a multi-IMU 200, which is composed of two island-like structural units 221, in which the two connecting units 221b are arranged in a positional relationship where they are located on adjacent sides (edges) of a rectangular opening 211.

[0135] In other words, the multi-IMU 200 in Figure 17 is composed of island-like structures 221-31 and 221-32, with island sections 221a-31 and 221a-32 adjacent to each other, a connecting section 221b-31 provided on the horizontal side of the opening 211, and a connecting section 221b-32 provided on the vertical side of the opening 211.

[0136] Thus, in the multi-IMU 200 shown in Figure 17, the two connection points 221b-31 and 221b-32 are positioned on the horizontal and vertical sides of the opening 211, respectively, and are structured to be located at separate positions on the printed circuit board 210 that transmits vibrations.

[0137] Therefore, the island-like structures 221-31 and 221-32 are designed to make it difficult for vibrations to propagate, thereby suppressing vibration interference between IMUs 201-31 and 201-32 and making it possible to suppress the generation of hum noise caused by vibrations.

[0138] In Figure 17, an example is shown in which the connecting portion 221b-31 is connected to a part of the left portion from the center position of the upper horizontal edge of the opening 211 in the figure, and the connecting portion 221b-32 is connected to a part of the right vertical edge of the opening 211 in the figure. However, it is also possible to connect the connecting portion 221b-32 to a part of the right portion from the center position of the upper horizontal edge of the opening 211 in the figure, and the connecting portion 221b-31 is connected to a part of the left vertical edge of the opening 211 in the figure.

[0139] Alternatively, IMU placement units 200UC, each consisting of a multi-IMU 200 as shown in Figure 17, may be arranged adjacently in the horizontal and vertical directions to form a multi-IMU 200 consisting of two or more island-shaped structural units 221.

[0140] <Part 4> In the above, we have described an example in which the island-like structure 221 is configured as a unit, and the two connecting parts 221b are positioned on adjacent sides of the rectangular opening 211.

[0141] However, the two connecting portions 221b may be positioned at the corners of the rectangular opening 211 rather than at the sides.

[0142] Figure 18 shows an example configuration of a multi-IMU 200, which is composed of two island-like structural units 221, in which the two connecting units 221b are positioned at the diagonal corners of a rectangular opening 211.

[0143] In other words, the multi-IMU 200 in Figure 18 is composed of island-like structures 221-41 and 221-42, with island sections 221a-41 and 221a-42 adjacent to each other, and connecting sections 221'b-41 and 221'b-42 provided at diagonal corners of the opening 211.

[0144] Thus, in the multi-IMU 200 shown in Figure 18, the two connection points 221'b-41 and 221'b-42 are located at the diagonal corners of the rectangular opening 211, which are the upper left and lower right corners, respectively, and are positioned at the furthest possible locations on the opening 211 in the printed circuit board 210 that transmits vibrations.

[0145] Therefore, the island-like structures 221-41 and 221-42 are designed to make it difficult for vibrations to propagate, thereby suppressing interference caused by vibrations between IMUs 201-41 and 201-42, and making it possible to suppress the generation of hum noise caused by interference.

[0146] In Figure 18, an example is shown in which both connecting parts 221'b-41 and 221'b-42 are positioned at diagonal corners formed by the upper left and lower right corners of the rectangular opening 211, respectively. However, the connecting parts 221b-41 and 221b-42 may also be positioned at diagonal corners formed by the upper right and lower left corners of the rectangular opening 211, respectively.

[0147] Alternatively, IMU placement units 200UD, each consisting of a multi-IMU 200 as shown in Figure 18, may be arranged adjacently in the horizontal and vertical directions to form a multi-IMU 200 consisting of two or more island-shaped structural units 221.

[0148] <<4. Third Embodiment>> <Part 1> In the above, we have described an example in which island-shaped structures 221 are formed in openings 211 provided on the printed circuit board 210, and the connection portions 221b are arranged to be separated from each other, thereby suppressing the propagation of drive vibrations of each island portion 221a, reducing interference due to vibration, and suppressing the generation of hum noise caused by interference.

[0149] However, in addition to this configuration, a heavy object with a sufficiently large weight relative to the IMU 201 (for example, about 10g or more) may be placed on the back side of the island portion 221a to increase the rigidity of the island portion 221a, thereby making it difficult for vibrations to propagate, reducing interference due to vibrations, and suppressing the generation of hum noise caused by interference.

[0150] Figure 19 shows an example of the back configuration of the multi-IMU 200, in which heater resistors are placed as heavy objects on the back side of island sections 221a-51 to 221a-54 to increase the rigidity of island section 221a.

[0151] Furthermore, the surface structure in Figure 19 is the same as that of the multi-IMU200 in Figure 10, so its explanation will be omitted.

[0152] In other words, the multi-IMU 200 in Figure 19 is equipped with island-like structures 221-51 to 221-54, and heater resistors 251-1 and 251-2 are placed on each island 221a as heavy objects.

[0153] More specifically, heater resistors 251-51-1 and 251-51-2 are located in island section 221a-51, heater resistors 251-52-1 and 251-52-2 are located in island section 221a-52, heater resistors 251-53-1 and 251-53-2 are located in island section 221a-53, and heater resistors 251-54-1 and 251-54-2 are located in island section 221a-54.

[0154] This configuration improves the rigidity of the island-like structures 221-51 to 221-54, thereby suppressing the propagation of operational vibrations from other IMUs 201 via the connection parts 221b-51 to 221b-54 and the printed circuit board 210, and reducing vibration-related interference, thereby suppressing the generation of hum noise caused by interference.

[0155] Furthermore, the heater resistor 251 may be placed on the back side of the island portion 221a in the multi-IMU 200, which consists of two island-shaped structures 221 as described with reference to Figures 15 to 18, and this configuration will achieve the same effect.

[0156] <Part 2> In the above, we have described an example in which vibrations are less likely to propagate and humming is suppressed by increasing the rigidity of the island portion 221a by placing a heavy object on the back side of the island portion 221a. However, any heavy object that is sufficiently large relative to the IMU 201 can be used, for example, by attaching a metal plate.

[0157] Figure 20 shows an example of the back configuration of the multi-IMU 200, in which a metal plate is attached to the back of the island portion 221a as a weight to increase the rigidity of the island portion 221a.

[0158] Furthermore, the surface structure in Figure 20 is the same as that of the multi-IMU200 in Figure 10, so its explanation will be omitted.

[0159] In other words, the multi-IMU 200 in Figure 20 is equipped with island-like structures 221-61 to 221-64, and metal plates 261-61 to 261-64 are attached to each of the island sections 221a-61 to 221a-64 as weights.

[0160] This configuration improves the rigidity of the island-like structures 221-61 to 221-56, thereby suppressing the propagation of operating vibrations from other IMUs 201 via the connection parts 221b-61 to 221b-64 and the printed circuit board 210, and reducing interference related to vibrations, thereby suppressing the generation of hum noise caused by interference.

[0161] Furthermore, in the multi-IMU 200 consisting of two island-shaped structural parts 221 as described with reference to Figures 15 to 18, the metal plate 261 may be placed on the back side of the island part 221a, and this configuration will achieve the same effect.

[0162] <<5. Fourth Embodiment>> In the above, we have described an example in which rigidity is improved by placing a heavy object on the back side of the island portion 221a of the island-shaped structure 221, thereby suppressing the propagation of operating vibrations and reducing interference related to vibrations, and thereby suppressing the generation of hum noise caused by interference.

[0163] However, vibrations generated in the island portions 221a may be reduced by applying a substance with a viscosity higher than a predetermined viscosity, such as grease, to the island portions 221a so as to surround and fill the IMU 201.

[0164] Figure 21 is a side view of the island portion 221a, which is coated with a highly viscous substance such as grease, surrounding the IMU 201.

[0165] In the island portion 221a shown in Figure 21, grease 271, a highly viscous substance, is applied to the island portion 221a so as to surround the IMU 201-71.

[0166] In other words, since the operating vibrations of the IMU201-71 are transmitted through the island portion 221a, applying grease 271 with a viscosity higher than a predetermined viscosity to surround and fill the IMU201-71 in the island portion 221a will dampen the vibrations of the island portion 221a, thereby suppressing the propagation of the operating vibrations of the IMU201. The viscosity of the grease 271 should preferably be such that it remains in the applied area within the normal operating temperature range and shock / acceleration range.

[0167] Furthermore, for example, as shown in Figure 22 for IMUs 201-81 and 201-82, when the distance between adjacent units is narrow, applying grease 271' across both units, together with the grease 271 applied to the surrounding area, dampens the vibrations of the island portion 221a through which the operating vibrations of IMUs 201-81 and 201-82 are transmitted, thereby suppressing the propagation of operating vibrations of IMUs 201-81 and 201-82.

[0168] As a result, in both cases, the propagation of operating vibrations from the IMU201 is suppressed, thus suppressing interference related to vibrations, and thus making it possible to suppress the generation of hum noise caused by interference.

[0169] <<6. Fifth Embodiment>> In the above, we have described an example in which, by applying high-viscosity grease 271 to the island portion 221a so as to surround the IMU 201, the vibrations of the island portion 221a, which are directly transmitted from the IMU 201, are attenuated. As a result, the operating vibrations of the IMU 201 are suppressed, and the generation of hum noise is reduced.

[0170] Incidentally, although the printed circuit board 210 was configured assuming a rigid board, it may be replaced with a flexible board made of a flexible material such as polyimide to suppress the propagation of drive vibrations between multiple IMUs 201.

[0171] Figure 23 shows an example configuration of a multi-IMU 200 in which a flexible printed circuit board 291 is used instead of the printed circuit board 210, and IMUs 201-91 to 201-94 are mounted on the flexible printed circuit board 291.

[0172] The left side of Figure 23 shows an example of the surface configuration of the multi-IMU200, and the right side of Figure 23 shows an example of the back surface configuration of the multi-IMU200.

[0173] Specifically, IMUs 201-91 to 201-94 are formed on the surface of the multi-IMU 200, and each is mounted on a flexible printed circuit board 291, with a control IC 202 also provided. However, since the flexible circuit board 291 is soft, mounting the IMUs 201-91 to 201-94 directly would cause problems in the mounting process. For this reason, reinforcing plates 201P-91 to 201P-94, made of, for example, glass epoxy board or stainless steel plate, are attached to the back of the mounting surface of each IMU 201-91 to 201-94. The reinforcing plates 201P-91 to 201P-94 suppress the occurrence of problems in the mounting process of the IMUs 201-91 to 201-94 onto the flexible circuit board 291.

[0174] Furthermore, each of the IMUs 201-91 to 201-94 in Figure 23 has a configuration in which the oscillator 11 and readout circuit 13 in IMU1 of Figure 1 are arranged in parallel with the configuration corresponding to the base 12.

[0175] Therefore, only the configuration corresponding to the base 12 in IMUs 201-91 to 201-94 is visible on the back of the multi-IMU 200. In addition, a connector 203 is formed at the end of the flexible printed circuit board 291 on the back of the multi-IMU 200.

[0176] With this configuration, each of the IMUs 201-91 to 201-94 is connected by a flexible printed circuit board made of a flexible material. This suppresses the propagation of operating vibrations between the IMUs 201-91 to 201-94, reducing vibration-related interference and thereby suppressing the generation of hum noise caused by interference.

[0177] <<7. Sixth Embodiment>> In the above, we have described a configuration in which the rigid printed circuit board 210 is replaced with a flexible printed circuit board made of a flexible material such as polyimide, thereby suppressing the propagation of drive vibrations between multiple IMUs 201.

[0178] However, it is also possible to mount one IMU on a single circuit board, and further provide connectors that can electrically connect the front and back surfaces of each circuit board, thereby electrically connecting them and physically connecting the circuit boards in a stacked manner. This configuration allows for the suppression of the propagation of operational vibrations between IMUs on each circuit board due to friction between the connectors.

[0179] Figure 24 shows an example configuration of a multi-IMU200 in which one IMU is mounted on a single substrate, and an electrically connectable connector bracket is provided on both the front and back of each substrate. By inserting the connectors through the brackets, the substrates are electrically connected and physically connected in a stacked manner.

[0180] Note that the left side of Figure 24 is an exploded perspective view of the multi-IMU200, and the right side of Figure 24 is a perspective view with only the bottom circuit board 311-5 separated.

[0181] The multi-IMU 201 in Figure 24 consists of substrates 311-1 to 311-5 and support columns 321-1 to 321-4.

[0182] Boards 311-1 to 311-4 are each provided with IMUs 201-101 to 201-104, and board 311-5 is provided with a control IC 202.

[0183] Each of the circuit boards 311-2 to 311-5 is provided with concave connectors 313-1 to 313-4 on the upper surface side in the figure, and each of the circuit boards 311-1 to 311-4 is provided with convex connectors 312-1 to 312-4 on the lower surface side in the figure.

[0184] Then, the concave connectors 313-1 to 313-4 are mated with the convex connectors 312-1 to 312-4 facing each other, thereby connecting them electrically and physically, and as a result, the substrates 311-1 to 311-5 are connected in an electrically and physically stacked state.

[0185] Of the stacked substrates 311-1 to 311-5, substrates 311-1 and 311-5 are larger in size than substrates 311-2 to 311-4. In addition, substrate 311-5, which is stacked at the upper end, has holes 311a-1 to 311a-4 at each of its four corners.

[0186] Screws 322-1 to 322-4 are inserted through each of the holes 311a-1 to 311a-4 and engaged with each of the support columns 321-1 to 321-4, thereby joining the upper and lower ends of the stacked substrates 311-1 to 311-5, and sandwiching the substrates 311-2 to 311-4 between them, so that the multi-IMU 200 in Figure 24 is fixed as a whole.

[0187] With this configuration, each of the boards 311-1 to 311-5 is connected by the mating of concave connectors 313-1 to 313-4 and convex connectors 312-1 to 312-4 located at opposing positions. As a result, vibration propagation is attenuated by the friction involved in the mating, making it difficult for vibrations to propagate between the boards 311-1 to 311-5.

[0188] Therefore, the mutual operational vibrations between IMUs 201-101 to 201-104, each provided on substrates 311-1 to 311-4, are less likely to propagate, and interference related to vibrations is reduced, making it possible to suppress the generation of hum noise caused by interference.

[0189] <<8. Seventh Embodiment>> In the above, we have described a configuration in which multiple circuit boards, each equipped with a single IMU, are provided, and electrically connectable connectors are provided on both the front and back surfaces of each circuit board. By inserting these connectors, the boards are electrically connected and physically connected in a stacked manner.

[0190] However, by providing multiple connectors on a single circuit board and connecting an IMU201 through each of these connectors, the transmission of vibrations is attenuated by the friction involved in the mating of the connectors. Furthermore, if the compatibility of the operating vibrations is poor and hum noise is easily generated, the generation of hum noise can be suppressed overall by replacing it with a different IMU201 that generates operating vibrations of a different frequency and connecting it via a connector.

[0191] Figure 25 shows an example of a multi-IMU200 configuration in which multiple connectors are provided on a single circuit board, and an IMU201 is connected through each of the connectors.

[0192] Note that the left side of Figure 25 is a top view of the Multi-IMU 200, and the right side of Figure 25 is an exploded perspective view of the Multi-IMU 200.

[0193] In other words, the multi-IMU 200 in Figure 25 consists of connectors 351-101 to 351-104, a control IC 202 that controls the overall operation of the multi-IMU 200, and a connector 203 used for connecting to external devices, all located on a printed circuit board 210.

[0194] Furthermore, IMUs 201-111 to 201-114 are electrically and physically connected via connectors 351-101 to 351-104, respectively. Although not shown in the diagram, IMUs 201-111 to 201-114 are each provided with connectors corresponding to connectors 351-101 to 351-104.

[0195] In this configuration, each of the connectors (not shown) of IMU201-111 to IMU201-114 is mated and connected to the corresponding connectors 351-101 to 351-104. Due to the friction involved in the mating, the operating vibrations of each of the IMU201-111 to IMU201-114 are attenuated and propagated to the printed circuit board 210.

[0196] As a result, the operating vibrations of IMU201-111 to IMU201-114 are less likely to propagate to the printed circuit board 210 via the respective connectors 351-101 to 351-104.

[0197] Therefore, since the mutual operational vibrations between IMUs 201-111 to 201-114 are less likely to propagate, interference related to vibrations is reduced, and the generation of hum noise caused by interference can be suppressed.

[0198] Furthermore, if humming occurs even with such a configuration, the humming noise can be suppressed by replacing it with another IMU201 with different operating vibrations, thereby creating a combination where the overall operating vibrations do not interfere.

[0199] <<9. Eighth Embodiment>> In the above, we have described a configuration in which multiple connectors are provided on the printed circuit board, and the IMU201 is connected through each of these connectors, thereby attenuating the propagation of operating vibrations from the IMU201 to the printed circuit board due to friction related to the mating of the connectors, and suppressing hum noise.

[0200] However, a structure that makes it difficult for operational vibrations between IMU201s to propagate may be created by attaching multiple IMU201s to a relatively heavy base.

[0201] Figure 26 is a side view of a multi-IMU200, in which multiple IMU201s are attached to a relatively heavy base.

[0202] In the multi-IMU200 shown in Figure 26, IMUs 201-121 and 201-122 are connected to a base 362 that is significantly heavier than the IMU 201, for example, a relatively heavy base of about 10g or more, via double-sided tapes 361-111 and 361-112.

[0203] With this configuration, the IMUs 201-121 and 201-122 are fixed to the heavy base 362 using double-sided tapes 361-111 and 361-112, respectively, thereby suppressing the propagation of operating vibrations.

[0204] As a result, the propagation of operating vibrations between IMU201-121 and 201-122 is suppressed, thus reducing vibration-related interference and the resulting hum noise.

[0205] In this specification, a system refers to a collection of multiple components (devices, modules (parts), etc.), regardless of whether all components are located in the same enclosure. Therefore, multiple devices housed in separate enclosures and connected via a network, and a single device containing multiple modules within a single enclosure, are both considered systems.

[0206] The embodiments described herein are not limited to those described above, and various modifications are possible without departing from the gist of this disclosure.

[0207] Furthermore, this disclosure can also be structured as follows: <1> A predetermined number of mounting sections, each equipped with one IMU (Inertial Measurement Unit), The substrate comprises a predetermined number of connection parts that connect one of the mounting parts to the edge of an opening provided in the substrate, The aforementioned connection portion has lower rigidity than the aforementioned substrate. Inertial measuring device. <2> The aforementioned connection portion has lower rigidity than the aforementioned mounting portion. <1> The inertial measuring device described in [reference]. <3> The aforementioned opening is rectangular, Each of the connecting parts connects each side of the rectangle to the mounting part. <1> or <2> The inertial measuring device described in [reference]. <4> The mounting portion has a shape in which the area that becomes the opening is divided into a predetermined number of substantially equal parts. Each of the connecting parts connects a portion of each side of the rectangle to the mounting part. <3> The inertial measuring device described in [reference]. <5> The aforementioned predetermined number is 4. The mounting section has a shape in which the area that will become the opening is divided into four substantially equal parts. Each of the connecting parts connects the mounting part to a portion to the right or left of the center of each side of the rectangle. <4> The inertial measuring device described in [reference]. <6> The aforementioned predetermined number is 4. The mounting section has a shape in which the area that will become the opening is divided into four substantially equal parts. Each of the connecting parts connects the corners of the rectangle to the mounting part. <4> The inertial measuring device described in [reference]. <7> The aforementioned predetermined number is 2. The mounting section has a shape in which the area that becomes the opening is divided into two almost equally. Each of the connecting parts connects a portion of the short side opposite the rectangle to the mounting part. <4> The inertial measuring device described in [reference]. <8> The aforementioned predetermined number is 2. The mounting section has a shape in which the area that becomes the opening is divided into two almost equal parts. The aforementioned connecting portion connects the mounting portion to the right or left portion of the center of the long side opposite the rectangular shape. <4> The inertial measuring device described in [reference]. <9> The aforementioned predetermined number is 2. The mounting section has a shape in which the area that becomes the opening is divided into two almost equal parts. The first connecting portion connects the right or left portion of the center of the long side of the rectangle to the mounting portion. The second connecting portion connects a part of the shorter side of the rectangle to the mounting portion. <4> The inertial measuring device described in [reference]. <10> The aforementioned predetermined number is 2. The mounting section has a shape in which the area that becomes the opening is divided into two almost equal parts. Each of the aforementioned connecting parts connects the diagonal corners of the rectangle to the mounting part. <4> The inertial measuring device described in [reference]. <11> Units comprising a predetermined number of mounting sections and a predetermined number of connecting sections, enclosed within the opening, are arranged in a plurality in at least one of the horizontal and vertical directions. <1> ~ <10> An inertial measuring device as described in any of the following. <12> The mounting section includes a heavy object on the back surface of the surface on which the IMU is mounted, which is significantly heavier than the IMU. <1> ~ <11> An inertial measuring device as described in any of the following. <13> The aforementioned heavy object includes a heater resistor and a metal plate. <12> The inertial measuring device described in [reference]. <14> In the mounting section, a substance with a viscosity higher than a predetermined level is applied to surround and fill the IMU. <1> ~ <13> An inertial measuring device as described in any of the following. <15> The substance with a viscosity higher than the predetermined viscosity is grease. <14> The inertial measuring device described in [reference]. <16> The spacing between adjacent mounting parts is such that they do not physically come into contact even when the main body undergoes thermal expansion. <1> ~ <15> An inertial measuring device as described in any of the following. <17> The distance between the mounting portion and the edge of the opening is such that they do not physically come into contact even when the main body undergoes thermal expansion. <1> ~ <16> An inertial measuring device as described in any of the following. <18> The system includes a combining unit that combines and outputs the detection results of multiple IMUs. <1> ~ <17> An inertial measuring device as described in any of the following. [Explanation of Symbols]

[0208] 200 Multi-IMU (Inertial Measuring Unit), 201, 201-1 to 201-4, 201-11, 201-12, 201-21, 201-22, 201-31, 201-32, 201-41, 201-42, 201-81, 201-82, 201-91 to 201-94, 201-101 to 201-104, 201-111 to 201-114, 201-121, 201-122 IMU, 210 Printed circuit board, 211 Aperture, 221-1 to 221-4,221-11,221-12,221-21,221-22,221-31,221-32,2 21-41, 221-42, 221-51 to 221-54, 221-61 to 221-64, 221'-1 to 221'-4 island structure, 221a, 221a-1 to 221a-4, 221a-11, 221a-12, 221a-21, 221a-22, 221a-31, 221a-32, 22 1a-41, 221a-42, 221a-51 to 221a-54, 221a-61 to 221a-64, 221'a, 221'a-1 to 221'a-4 island, 221b,221b-1 to 221b-4,221b-11,221b-12,221b-11,221b-12,221b-21,221b-22,221b-31,22 1b-32,221b-41,221b-42,221b-51 to 221b-54,221b-61 to 221b-64,221'b,221'b-1 to 221'b-4 Connection, 251,251-51-1,251-51-2,251-52-1,251-52-2,251-53-1,251-53-2,251-54-1,251-54-2 Heater resistance, 261-61 to 261-64 Metal plate, 271, 271' Grease, 291 Flexible circuit board, 311-1 to 311-5 Printed circuit board, 312-1 to 312-4 Convex connector, 313, 313-1 to 313-4 Concave connector, 351, 351-1 to 351-4 Connector, 361-111, 361-112 Double-sided tape, 362 Base

Claims

1. Multiple mounting units, each equipped with one IMU (Inertial Measurement Unit), Each of the edges of the openings provided on the substrate is provided with a plurality of connecting parts, each connecting the substrate to one of the mounting parts, The aforementioned connection portion has lower rigidity than the aforementioned substrate. Inertial measuring device.

2. The aforementioned connection portion has lower rigidity than the aforementioned mounting portion. The inertial measuring device according to claim 1.

3. The aforementioned opening is rectangular, Each of the connecting parts connects the substrate and the one mounting part to a part of one of the multiple sides that make up the rectangle. The inertial measuring device according to claim 1.

4. The mounting portion has a shape in which the area that becomes the opening is divided into the plurality of areas in a substantially equal manner. Each of the connecting parts connects a portion of one of the multiple sides constituting the rectangle to one of the mounting parts. The inertial measuring device according to claim 3.

5. The aforementioned plural is 4, Each of the mounting sections has a shape in which the area that will become the opening is divided into four substantially equal parts. Each of the connecting parts connects the one mounting part to a portion to the right or left of the center position of one of the multiple sides constituting the rectangle. The inertial measuring device according to claim 4.

6. The aforementioned plural is 4, Each of the mounting sections has a shape in which the area that will become the opening is divided into four substantially equal parts. Each of the connecting parts connects one of the multiple corners constituting the rectangle to the one mounting part. The inertial measuring device according to claim 4.

7. The aforementioned plurality is 2, Each of the mounting sections has a shape in which the area that becomes the opening is divided into two substantially equal parts. The connecting portion connects each of the shorter sides that are opposite each other among the multiple sides that make up the rectangle to the one mounting portion. The inertial measuring device according to claim 4.

8. The aforementioned plurality is 2, Each of the mounting sections has a shape in which the area that becomes the opening is divided into two substantially equal parts. The connecting portion connects the one mounting portion to the right or left portion of the center of each of the longer sides that are opposite each other among the multiple sides that make up the rectangle. The inertial measuring device according to claim 4.

9. The aforementioned plurality is 2, Each of the mounting sections has a shape in which the area that becomes the opening is divided into two substantially equal parts. The first connecting portion connects the right or left portion of the center of one of the longer sides of the rectangle to the one mounting portion. The second connecting portion connects a part of the shorter side of the multiple sides constituting the rectangle to one of the mounting portions. The inertial measuring device according to claim 4.

10. The aforementioned plurality is 2, The aforementioned mounting portion has a shape in which the area that becomes the opening is divided into two substantially equal parts. Each of the connecting parts connects one of the mounting parts to each of the diagonal corners among the multiple corners that make up the rectangle. The inertial measuring device according to claim 4.

11. Units comprising the plurality of mounting portions and the plurality of connecting portions enclosed within the opening are arranged in a row in at least one of the horizontal and vertical directions. The inertial measuring device according to claim 1.

12. The mounting section includes a heavy object on the back surface of the surface on which the IMU is mounted, which is significantly heavier than the IMU. The inertial measuring device according to claim 1.

13. The aforementioned heavy object includes a heater resistor and a metal plate. The inertial measuring device according to claim 12.

14. In the mounting section, a substance with a viscosity higher than a predetermined level is applied to surround and fill the IMU. The inertial measuring device according to claim 1.

15. The substance with a viscosity higher than the predetermined viscosity is grease. The inertial measuring device according to claim 14.

16. The spacing between adjacent mounting parts is such that they do not physically come into contact even when the main body undergoes thermal expansion. The inertial measuring device according to claim 1.

17. The distance between the mounting portion and the edge of the opening is such that they do not physically come into contact even when the main body undergoes thermal expansion. The inertial measuring device according to claim 1.

18. The system includes a combining unit that combines and outputs the detection results of multiple IMUs. The inertial measuring device according to claim 1.

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