Method for detecting vibration

Abstract

To provide a method for accurately detecting vibration of a target object by transmission and reception of waves.SOLUTION: A method for detecting vibration of a target object vibrating at a predetermined frequency by an electronic apparatus that radiates electromagnetic waves includes: a step of setting a distance between the electronic apparatus and the target object to be less than a predetermined value based on a diameter of an equiphase surface of the target object and a half-value width of a gain of an antenna of the electronic apparatus; and a step of detecting the vibration of the target object by the electronic apparatus separated from the target object by the set distance.SELECTED DRAWING: Figure 22

Description

[Technical Field]

[0001] The present disclosure relates to a vibration detection method. [Background technology]

[0002] For example, in fields such as the automobile industry, technology for measuring the distance between a vehicle and a predetermined object has become increasingly important. In particular, in recent years, various RADAR (Radio Detecting and Ranging) technologies have been researched, such as millimeter-wave radar, which measures the distance between a vehicle and an object by transmitting radio waves and receiving waves reflected by the object, such as an obstacle. Such technologies for measuring distance are expected to become increasingly important in the future with the development of technologies for assisting drivers in driving and technologies related to autonomous driving, which automates driving in part or in whole.

[0003] Other proposed technologies include detecting vibrations of an object by transmitting and receiving waves, such as millimeter waves, to detect abnormalities in the object. Non-Patent Document 1 discloses a technology for analyzing the vibration mode of a specific object by detecting its vibration in fields such as civil engineering or architecture. Figure 8 in Non-Patent Document 1 shows that the vibration mode of a damaged bridge changes from its normal state, and proposes detecting bridge abnormalities by detecting the vibration mode. Chapter 2 of Non-Patent Document 2 proposes vibration measurement and a structure excitation method using a laser Doppler vibrometer (LDV). Chapter 3 of Non-Patent Document 2 proposes detecting the presence of defects by applying non-contact acoustic excitation to a concrete wall with circular defects of different sizes, as shown in Figure 9, and acquiring the vibrations using an LDV. Non-Patent Document 3 also discloses a technology for acquiring surface vibrations of a structure using a radar sensor. [Prior art documents] [Non-patent literature]

[0004]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] For example, if the vibration of an object can be detected with good accuracy by transmitting and receiving waves such as radio waves, it can be expected to be useful in a wide variety of fields.

[0006] An object of the present disclosure is to provide a vibration detection method that detects vibrations of an object with high accuracy by transmitting and receiving waves. [Means for solving the problem]

[0007] A vibration detection method according to an embodiment includes: A method for detecting vibrations of an object vibrating at a predetermined frequency by an electronic device that irradiates electromagnetic waves, comprising: setting a distance between the electronic device and the object to be less than a predetermined value based on a diameter of an equiphase surface of the object and a half-width of a gain of an antenna of the electronic device; detecting vibrations of the object by the electronic device spaced apart from the object by the set distance; A vibration detection method comprising: [Effects of the Invention]

[0008] According to one embodiment, it is possible to provide a vibration detection method that can detect vibration of a vibrating body with high accuracy by transmitting and receiving waves. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the configuration of a system including a detection device and electronic devices according to an embodiment. [Figure 2] 1A and 1B are diagrams illustrating a usage mode of a detection device according to an embodiment. [Figure 3] FIG. 2 is a functional block diagram illustrating a schematic configuration of a detection device according to an embodiment. [Figure 4] FIG. 2 is a diagram illustrating the configuration of a signal processed by a detection device according to an embodiment. [Figure 5] FIG. 2 illustrates signal processing by a detection device according to one embodiment. [Figure 6] FIG. 2 illustrates signal processing by a detection device according to one embodiment. [Figure 7] FIG. 2 illustrates signal processing by a detection device according to one embodiment. [Figure 8] 1A and 1B are schematic diagrams illustrating examples of antenna arrangements and operation principles in an antenna array of a detection device according to an embodiment; [Figure 9] 1A and 1B are diagrams illustrating exemplary antenna arrangements in an antenna array of a detection device according to one embodiment. [Figure 10] FIG. 1 is a functional block diagram illustrating a schematic configuration of an electronic device according to an embodiment. [Figure 11] 10A and 10B are diagrams illustrating an example of a correspondence relationship between a vibration waveform of a vibration source and a deformation state of an object according to an embodiment. [Figure 12] 10A and 10B are diagrams illustrating an example of a correspondence relationship between a vibration waveform of a vibration source and a deformation state of an object according to an embodiment. [Figure 13] FIG. 10 is a diagram showing the temporal correspondence between continuous data acquired by a detection device and an excitation waveform according to an embodiment. [Figure 14] 10 is a flowchart illustrating an operation of an electronic device according to an embodiment. [Figure 15A] 1A and 1B are diagrams illustrating examples of vibration mode shapes of an object according to an embodiment. [Figure 15B] 1A and 1B are diagrams illustrating examples of vibration mode shapes of an object according to an embodiment. [Figure 15C] 1A and 1B are diagrams illustrating examples of vibration mode shapes of an object according to an embodiment. [Figure 16] 10A and 10B are diagrams illustrating vibration waveforms used when a vibration source vibrates an object according to an embodiment. [Figure 17] 1 is a diagram showing an example of a waveform detected by the detection device 1 when an object is vibrated. [Figure 18] FIG. 10 is a diagram showing an example in which waveforms measured at each measurement position are time-synchronized by an electronic device according to an embodiment. [Figure 19A] FIG. 10 is a diagram showing the displacement of an object at each measurement position at the instant of the same phase. [Figure 19B] FIG. 10 is a diagram showing the displacement of the object for each measurement position after a predetermined offset time has elapsed from the instant of in-phase. [Figure 19C]FIG. 10 is a diagram showing the displacement of the object for each measurement position after a predetermined offset time has elapsed from the instant of in-phase. [Figure 19D] FIG. 10 is a diagram showing the displacement of the object for each measurement position after a predetermined offset time has elapsed from the instant of in-phase. [Figure 20A] 1 is a diagram illustrating an example of a detection wave irradiated onto an object from a detection device according to an embodiment and a measurement area. FIG. [Figure 20B] 1 is a diagram illustrating an example of a detection wave irradiated onto an object from a detection device according to an embodiment and a measurement area. FIG. [Figure 21A] 1A and 1B are diagrams illustrating an example of a measurement area of ​​a detection device and a change in the shape of an object according to an embodiment. [Figure 21B] 1 is a diagram showing an example of a measurement area of ​​a detection device 1 according to an embodiment and a change in shape of an object 200. FIG. [Figure 22] 1A to 1C are diagrams illustrating a vibration detection method using a detection device 1 according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment will be described with reference to the drawings.

[0011] In the present disclosure, an "electronic device," a "detection device," and a "signal generator" may refer to devices powered by electricity. Various known technologies can be employed to supply power to these devices, and therefore detailed description thereof will be omitted. Furthermore, a "user" may refer to a person (typically a human) who uses an electronic device, a detection device, and / or a system including these according to an embodiment. The user may include a person who detects vibrations of an object using an electronic device and / or a detection device according to an embodiment. Furthermore, an "object" may refer to various objects whose vibrations are detected by an electronic device and / or a detection device according to an embodiment. In the present disclosure, an "object" may include, for example, a building, an apartment building or other structure, a bridge, a road, a highway, a structure under construction, a tunnel, a machine tool, and the like. In the present disclosure, an "object" may include, for example, an automobile, an automobile engine, a motor, a motorcycle, a shovel, a ship, and the like.

[0012] FIG. 1 is a diagram showing the configuration of a system including a detection device and an electronic device according to an embodiment.

[0013] The system according to an embodiment shown in FIG. 1 may include a detection device 1 and an electronic device 100. The system shown in FIG. 1 is used to detect vibrations of an object 200. In FIG. 1, the object 200 is shown as an elongated plate-like member. The object 200 is not limited to the shape shown in FIG. 1 and may have various shapes. The system according to an embodiment may also include a vibration source 300 that vibrates the object 200 and / or a signal generator 400 that outputs a predetermined signal to the vibration source 300. The system according to an embodiment shown in FIG. 1 may not include at least some of the functional units shown in FIG. 1, or may include other functional units as appropriate.

[0014] As shown in FIG. 1 , in a system according to one embodiment, a detection device 1 detects vibrations of an object 200. The detection device 1 may detect vibrations at one or more positions of the object 200. Therefore, the detection device 1 may detect vibrations at one or more positions of the object 200 from one or more arbitrary positions, such as position 1, position 2, ..., position n. The detection device 1 may be configured to be automatically or manually changeable, such as position 1, position 2, ..., position n. The detection device 1 may be appropriately equipped with a mechanism, such as a sliding mechanism, so that it can be displaced in the X-axis direction (positive and / or negative direction of the X-axis) shown in FIG. 1 . FIG. 1 illustrates the detection device 1 irradiating (transmitting) detection waves (transmission waves), such as radio waves, with a viewing angle θ toward the object 200 at each of positions 1, 2, ..., position n. The detection device 1 can detect the distance and / or relative speed between the detection device 1 and the object 200 by receiving reflected waves of the irradiated detection waves (transmission waves) at each of positions 1, 2, ..., position n. The detection device 1 outputs the results of detecting the vibration of the object 200 to the electronic device 100. For this reason, the detection device 1 is connected to the electronic device 100 by wire and / or wirelessly.

[0015] The electronic device 100 can receive the result of the detection of the vibration of the object 200 by the detection device 1 and measure the vibration mode of the object 200, etc. The electronic device 100 can also measure and output instantaneous changes in the displacement of the object 200, etc. The configuration and functions of the electronic device 100 will be described further below. In FIG. 1, the electronic device 100 is shown as a functional unit separate from the detection device 1. However, the electronic device 100 and the detection device 1 may be configured so that one includes (or functions as) the other.

[0016] The object 200 can be any type of object whose vibrations are detected by the detection device 1. As described above, the object 200 may have any type of shape. The object 200 may be configured to include any type of member. Furthermore, the object 200 may be configured to include any type of material. Since the object 200's vibrations are detected by the detection device 1, the object 200 may be configured to include a material that has a certain degree of elasticity. The object 200 is vibrated by the vibration source 300, i.e., vibrations are transmitted to the object 200. The object 200 may be vibrated by the vibration source 300 at any location.

[0017] The vibration source 300 has a function of vibrating the object 200, i.e., transmitting vibrations. The vibration source 300 may be configured to include various vibration generators, such as a piezoelectric element or a loudspeaker. The vibration source 300 may transmit its own deformation to the object 200. The vibration source 300 may be, for example, a vibration testing machine or an impact hammer. The number of vibration sources 300 may be one or more. The vibration source 300 may be installed outside the object 200, such as on the top, side, and / or back of the object 200, inside the object 200, or at a certain distance from the object 200. The vibration source 300 may be installed so as to be in contact with the object 200. In this case, the vibration source 300 can directly transmit its deformation to the object 200. Furthermore, the vibration source 300 may be spaced apart from the object 200. In this case, the vibration source 300 can transmit its deformation using a medium such as air. FIG. 1 illustrates a configuration in which one vibration source 300 vibrates the object 200. In one embodiment, a configuration in which multiple vibration sources 300 vibrate one object 200 may also be used. Furthermore, the vibration source 300 may be disposed in an appropriate position, for example, so that it can vibrate the object 200 effectively. As various vibration sources based on known technology may be employed as the vibration source 300, a detailed description thereof will be omitted.

[0018] The signal generator 400 has a function of generating a signal constituting the waveform of the vibration generated by the vibration source 300. For this purpose, the signal generator 400 is connected to the vibration source 300 via a wire and / or wirelessly. The signal generator 400 may generate any signal for generating various types of vibration in the vibration source 300. In one embodiment, the signal generator 400 may generate an acoustic signal. Since various types of signal generators based on known technologies may be employed as the signal generator 400, a detailed description thereof will be omitted. The signal generator 400 may be connected to the electronic device 100 and / or the detection device 1 via a wire and / or wirelessly. In FIG. 1, the signal generator 400 is shown as a functional unit separate from the electronic device 100. However, the signal generator 400 and the electronic device 100 may be configured so that one includes (or functions as) the other.

[0019] Using the system according to one embodiment shown in FIG. 1 , the detection device 1 can acquire instantaneous deformation of the object 200. For example, the object 200 may have a damaged portion 210 in a long plate-like shape. Hereinafter, the detection device 1 with a viewing angle θ can be used for such an object 200 to acquire the vibration mode of the object 200. In one embodiment, the electronic device 100 can use one detection device 1 to perform measurements in the order of position 1, position 2, ..., position n, starting from the left end. A vibration source 300 is installed on the object 200. The vibration source 300 can generate vibration based on an arbitrary waveform using a signal output from a signal generator 400.

[0020] Similar to a radar sensor that transmits and receives normal millimeter waves, the detection device 1 according to one embodiment can measure the distance between the detection device and an object in a situation where the object may be moving around the detection device. Furthermore, the detection device according to one embodiment can measure the distance between the detection device and an object even when both the detection device and the object are stationary. Hereinafter, the detection device 1 will be described as a millimeter wave sensor, which is small and highly portable as a radar sensor, and has a short wavelength and is therefore easy to detect minute vibrations.

[0021] Next, the detection device 1 and the electronic device 100 according to an embodiment will be further described.

[0022] First, an example of object detection by the detector 1 according to one embodiment will be described. As described above, the detector 1 according to one embodiment will be described assuming that it is a sensor based on millimeter-wave radar technology (millimeter-wave sensor). However, as will be described later, the detector 1 according to one embodiment may also be a sensor based on various vibration sensor technologies.

[0023] Fig. 2 is a diagram illustrating an example of a usage mode of the detection device 1 according to an embodiment. Fig. 2 shows an example of the detection device 1 having a sensor function and including a transmitting antenna and a receiving antenna according to an embodiment.

[0024] As shown in FIG. 2, the detector 1 according to an embodiment may include a transmitter and a receiver, which will be described later. As will be described later, the transmitter may include a transmit antenna array 24. The receiver may include a receive antenna array 31. Specific configurations of the detector 1, the transmitter, and the receiver will be described later. For ease of viewing, FIG. 2 shows a simplified view of the detector 1 including the transmit antenna array 24 and the receive antenna array 31. The detector 1 may also include at least one of the other functional units, such as at least a part of the signal processing unit 10 (FIG. 3) included in the detector 1, as appropriate. The detector 1 may also include at least one of the other functional units, such as at least a part of the signal processing unit 10 (FIG. 3), external to the detector 1. In FIG. 2, the detector 1 may be moving or may be stationary.

[0025] In the example shown in FIG. 2, the detection device 1 is shown in a simplified form, with a transmitter having a transmitting antenna array 24 and a receiver having a receiving antenna array 31. The detection device 1 may include, for example, multiple transmitters and / or multiple receivers. The transmitter may include a transmitting antenna array 24 consisting of multiple transmitting antennas. The receiver may include a receiving antenna array 31 consisting of multiple receiving antennas. Here, the positions at which the transmitters and / or receivers are installed in the detection device 1 are not limited to the positions shown in FIG. 2, and may be other positions as appropriate. The number of transmitters and / or receivers may be any number greater than or equal to one, depending on various conditions (or requirements) such as the detection range and / or detection accuracy of vibration by the detection device 1.

[0026] As described below, the detection device 1 transmits electromagnetic waves as transmission waves from the transmission antenna array 24. For example, if a predetermined object (e.g., the target object 200 shown in FIG. 2) is present around the detection device 1, at least a portion of the transmission waves transmitted from the detection device 1 is reflected by the object and becomes a reflected wave. Then, by receiving such a reflected wave, for example, by the receiving antenna array 31 of the detection device 1, the detection device 1 can detect the object as a target.

[0027] The detection device 1 including the transmitting antenna array 24 may typically be a RADAR (Radio Detecting and Ranging) sensor that transmits and receives radio waves. However, the detection device 1 is not limited to a radar sensor. The detection device 1 according to an embodiment may be a sensor based on, for example, LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) technology using light waves. Such sensors may include, for example, a patch antenna. Since technologies such as RADAR and LIDAR are already known, detailed descriptions thereof may be appropriately simplified or omitted. Furthermore, the detection device 1 according to an embodiment may be a sensor based on technology that detects objects by transmitting and receiving sound waves or ultrasonic waves. Furthermore, the detection device 1 according to an embodiment may be a vibration sensor other than the above-mentioned sensors.

[0028] The detection device 1 shown in FIG. 2 receives, from the receiving antenna array 31, reflected waves of transmitted waves transmitted from the transmitting antenna array 24. In this way, the detection device 1 can detect a predetermined object 200 that exists within a predetermined distance from the detection device 1 as a target. For example, as shown in FIG. 2, the detection device 1 can measure the distance L between the detection device 1 and the predetermined object 200. The detection device 1 can also measure the relative speed between the detection device 1 and the predetermined object 200. Furthermore, the detection device 1 can also measure the direction (arrival angle A) in which the reflected wave from the predetermined object 200 arrives at the detection device 1.

[0029] In Fig. 2, the XY plane may be, for example, a plane substantially parallel to the ground surface. In this case, the positive direction of the Z axis shown in Fig. 2 may indicate a vertically upward direction. In Fig. 2, the detection device 1 may be disposed on a plane parallel to the XY plane. Also, in Fig. 2, the target object 200 may be, for example, standing on the ground surface substantially parallel to the XY plane.

[0030] Here, the target object 200 may be, for example, any object present around the detection device 1. The target object 200 may include, for example, automobiles, automobile engines, motors, motorcycles, ships, buildings, apartment buildings and other structures, bridges, roads, highways, under-construction structures, tunnels, machine tools, and excavators present around the detection device 1. As described above, the target object 200 may be moving, stationary, or static. In the present disclosure, the object detected by the detection device 1 includes not only inanimate objects such as any object, but also living objects such as people, dogs, cats, horses, and other animals. The object detected by the detection device 1 of the present disclosure may include targets including people, objects, and animals detected using radar technology. In the present disclosure, the target object may include people, objects, and animals. The detection device 1 according to one embodiment detects vibrations of an object such as the target object 200. Therefore, hereinafter, the "target object 200" may also be referred to as the "vibrating body 200" as appropriate.

[0031] 2, the ratio between the size of the detection device 1 and the size of the target object 200 does not necessarily represent the actual ratio. Also, in FIG. 2, the transmitting antenna array 24 of the transmitting unit and the receiving antenna array 31 of the receiving unit are shown installed outside the detection device 1. However, in one embodiment, the transmitting antenna array 24 of the transmitting unit and / or the receiving antenna array 31 of the receiving unit may be installed at various positions on the detection device 1. For example, in one embodiment, the transmitting antenna array 24 of the transmitting unit and / or the receiving antenna array 31 of the receiving unit may be installed inside the detection device 1 so as not to be visible from the outside of the detection device 1.

[0032] In the following description, as a typical example, the transmitting antenna of the detector 1 is assumed to transmit radio waves in a frequency band such as millimeter waves (30 GHz or higher) or quasi-millimeter waves (for example, around 20 GHz to 30 GHz). Alternatively, the transmitting antenna of the detector 1 may transmit radio waves having a frequency bandwidth of 4 GHz, such as 77 GHz to 81 GHz. Alternatively, the transmitting antenna of the detector 1 may transmit radio waves at a high frequency (for example, 30 GHz to 300 GHz) above the millimeter wave band.

[0033] 3 is a block diagram showing the functional configuration of the detector 1 according to one embodiment. An example of the configuration of the detector 1 according to one embodiment will be described below.

[0034] When measuring distances and the like using millimeter-wave radar, frequency modulated continuous wave radar (hereinafter referred to as FMCW radar) is often used. FMCW radar generates a transmission signal by sweeping the frequency of the radio waves to be transmitted. Therefore, in a millimeter-wave FMCW radar using radio waves in the 79 GHz frequency band, for example, the frequency of the radio waves used has a frequency bandwidth of 4 GHz, such as 77 GHz to 81 GHz. Radar using the 79 GHz frequency band is characterized by a wider usable frequency bandwidth than other millimeter-wave / quasi-millimeter-wave radars, such as those in the 24 GHz, 60 GHz, and 76 GHz frequency bands. Hereinafter, such an embodiment will be described as an example.

[0035] The FMCW radar system used in the present disclosure may include an FCM (Fast-Chirp Modulation) system that transmits chirp signals at a shorter period than normal. The signal generated by the detector 1 is not limited to an FMCW signal. The signal generated by the detector 1 may be a signal of various systems other than the FMCW system. The transmission signal sequence stored in any memory unit may differ depending on these various systems. For example, in the case of the above-mentioned FMCW radar signal, a signal whose frequency increases and decreases with each time sample may be used. Since known technologies can be applied as appropriate to the above-mentioned various systems, a detailed description will be omitted.

[0036] As shown in Fig. 3, the detection device 1 according to one embodiment includes a signal processing unit 10. The signal processing unit 10 may include a signal generation processing unit 11 and a reception signal processing unit 12. The signal generation processing unit 11 performs processing to generate a transmission signal to be transmitted from the detection device 1. The reception signal processing unit 12 can perform various signal processing on a reception signal received by the detection device 1. The signal generation processing unit 11 and the reception signal processing unit 12 will be described further below as appropriate.

[0037] The detector 1 according to an embodiment includes a transmitter including a transmission DAC 21, a transmission circuit 22, a millimeter-wave transmission circuit 23, and a transmission antenna array 24. The detector 1 according to an embodiment includes a receiver including a reception antenna array 31, a mixer 32, a reception circuit 33, and a reception ADC 34. The detector 1 according to an embodiment may not include at least one of the functional units shown in FIG. 3, or may include functional units other than the functional units shown in FIG. 3. The detector 1 shown in FIG. 3 may be configured using a circuit that is basically similar to that of a general radar using electromagnetic waves in the millimeter-wave band or the like. Meanwhile, in the detector 1 according to an embodiment, the signal processing by the signal processing unit 10 may include processing different from that of conventional general radar.

[0038] The signal processing unit 10 included in the detection device 1 according to an embodiment can control the operation of the entire detection device 1, including the control of each functional unit constituting the detection device 1. In particular, the signal processing unit 10 performs various processes on signals handled by the detection device 1. The signal processing unit 10 may include at least one processor, such as a central processing unit (CPU) or a digital signal processor (DSP), to provide control and processing capabilities for executing various functions. The signal processing unit 10 may be implemented as a single processor, several processors, or individual processors. The processor may be implemented as a single integrated circuit. An integrated circuit is also called an IC (integrated circuit). The processor may be implemented as multiple integrated circuits and discrete circuits connected to each other in a communicative manner. The processor may be implemented based on various other known technologies. In an embodiment, the signal processing unit 10 may be configured as, for example, a CPU (hardware) and a program (software) executed by the CPU. At least a portion of the functional units constituting the detection device 1 according to an embodiment may be implemented by specific means in which software and hardware resources work together. The signal processing unit 10 may include a storage unit (memory) necessary for the operation of the signal processing unit 10 as appropriate.

[0039] The signal generation processing unit 11 of the signal processing unit 10 generates a signal to be transmitted from the detection device 1. In the detection device 1 according to one embodiment, the signal generation processing unit 11 may generate a transmission signal (transmission chirp signal) such as a chirp signal. In particular, the signal generation processing unit 11 may generate a signal whose frequency changes periodically and linearly (linear chirp signal). For example, the signal generation processing unit 11 may generate a chirp signal whose frequency periodically and linearly increases from 77 GHz to 81 GHz over time. Alternatively, the signal generation processing unit 11 may generate a signal whose frequency periodically and linearly increases (up-chirp) and decreases (down-chirp) from 77 GHz to 81 GHz over time. The signal generated by the signal generation processing unit 11 may be preset in, for example, the signal processing unit 10. Alternatively, the signal generated by the signal generation processing unit 11 may be stored in advance in, for example, an arbitrary storage unit in the signal processing unit 10. Chirp signals used in technical fields such as radar are well known, and therefore a detailed description thereof will be appropriately simplified or omitted. The signal generated by the signal generating processing unit 11 is supplied to the transmitting DAC 21. For this reason, the signal generating processing unit 11 may be connected to the transmitting DAC 21.

[0040] The transmission DAC (digital-to-analog converter) 21 has a function of converting the digital signal supplied from the signal generation processing unit 11 into an analog signal. The transmission DAC 21 may be configured to include a general digital-to-analog converter. The signal converted into an analog signal by the transmission DAC 21 is supplied to the transmission circuit 22. For this reason, the transmission DAC 21 may be connected to the transmission circuit 22.

[0041] The transmission circuit 22 has a function of converting the analog signal converted by the transmission DAC 21 into an intermediate frequency (IF) band. The transmission circuit 22 may be configured to include a general IF band transmission circuit. The signal processed by the transmission circuit 22 is supplied to the millimeter wave transmission circuit 23. For this reason, the transmission circuit 22 may be connected to the millimeter wave transmission circuit 23.

[0042] The millimeter-wave transmission circuit 23 has the function of transmitting the signal processed by the transmission circuit 22 as a millimeter wave (RF wave). The millimeter-wave transmission circuit 23 may be configured to include a general millimeter-wave transmission circuit. The signal processed by the millimeter-wave transmission circuit 23 is supplied to the transmission antenna array 24. For this reason, the millimeter-wave transmission circuit 23 may be connected to the transmission antenna array 24. The signal processed by the millimeter-wave transmission circuit 23 is also supplied to the mixer 32. For this reason, the millimeter-wave transmission circuit 23 may also be connected to the mixer 32.

[0043] The transmitting antenna array 24 is an array of multiple transmitting antennas. In Fig. 3, the configuration of the transmitting antenna array 24 is shown in a simplified form. The transmitting antenna array 24 transmits the signal processed by the millimeter-wave transmitting circuit 23 to the outside of the detection device 1. The transmitting antenna array 24 may be configured to include a transmitting antenna array used in a general millimeter-wave radar.

[0044] In this way, the detection device 1 according to one embodiment includes a transmitting antenna (transmitting antenna array 24) and can transmit a transmitting signal (for example, a transmitting chirp signal) as a transmitting wave from the transmitting antenna array 24.

[0045] For example, as shown in FIG. 3 , assume that an object such as a vibrating body 200 is present around the detection device 1. At least a portion of the vibrating body 200 may vibrate. In this situation, at least a portion of the transmission wave transmitted from the transmitting antenna array 24 is reflected by the object such as the vibrating body 200. At least a portion of the transmission wave transmitted from the transmitting antenna array 24 and reflected by the object such as the vibrating body 200 may be reflected toward the receiving antenna array 31.

[0046] The receiving antenna array 31 receives the reflected waves. Here, the reflected waves may be at least a portion of the transmission waves transmitted from the transmitting antenna array 24 that are reflected by an object such as the vibrating body 200.

[0047] The receiving antenna array 31 is an array of multiple receiving antennas. In FIG. 3, the configuration of the receiving antenna array 31 is shown in a simplified form. The receiving antenna array 31 receives reflected waves that are the result of reflection of the transmitted waves transmitted from the transmitting antenna array 24. The receiving antenna array 31 may be configured to include a receiving antenna array used in a general millimeter-wave radar. The receiving antenna array 31 supplies the received signals received as reflected waves to the mixer 32. For this reason, the receiving antenna array 31 may be connected to the mixer 32.

[0048] The mixer 32 converts the signal (transmission signal) processed by the millimeter-wave transmission circuit 23 and the reception signal received by the reception antenna array 31 into an intermediate frequency (IF) band. The mixer 32 may be configured to include a mixer used in a general millimeter-wave radar. The mixer 32 supplies the signal generated as a result of the combination to the reception circuit 33. For this reason, the mixer 32 may be connected to the reception circuit 33.

[0049] The receiving circuit 33 has a function of performing analog processing on the signal converted to the IF band by the mixer 32. The receiving circuit 33 may be configured to include a receiving circuit that converts to a general IF band. The signal processed by the receiving circuit 33 is supplied to the receiving ADC 34. For this reason, the receiving circuit 33 may be connected to the receiving ADC 34.

[0050] The receiving ADC (analog-to-digital converter) 34 has a function of converting the analog signal supplied from the receiving circuit 33 into a digital signal. The receiving ADC 34 may be configured to include a general analog-to-digital converter. The signal digitized by the receiving ADC 34 is supplied to the receiving signal processing unit 12 of the signal processing unit 10. For this reason, the receiving ADC 34 may be connected to the signal processing unit 10.

[0051] The reception signal processing unit 12 of the signal processing unit 10 has a function of performing various processes on the digital signal supplied from the reception ADC 34. For example, the reception signal processing unit 12 calculates the distance from the detector 1 to an object such as the vibrating body 200 based on the digital signal supplied from the reception ADC 34 (distance measurement). The reception signal processing unit 12 also calculates the relative velocity of the object such as the vibrating body 200 with respect to the detector 1 based on the digital signal supplied from the reception ADC 34 (velocity measurement). The reception signal processing unit 12 also calculates the azimuth angle of the object such as the vibrating body 200 as seen from the detector 1 based on the digital signal supplied from the reception ADC 34 (angle measurement or angle of arrival estimation). Specifically, I / Q converted data may be input to the reception signal processing unit 12. By inputting such data, the reception signal processing unit 12 performs fast Fourier transforms (2D-FFT) in the range direction and the velocity direction, respectively. Thereafter, the received signal processing unit 12 may suppress false alarms by removing noise points using processing such as CFAR (Constant False Alarm Rate) and make the probability constant. Then, the received signal processing unit 12 estimates the angle of arrival for points that satisfy the CFAR criteria, thereby obtaining the position of an object such as the vibrating body 200. Information generated as a result of measuring the distance, speed, and angle by the received signal processing unit 12 may be output to the electronic device 100.

[0052] In one embodiment, the reception signal processing unit 12 may detect (calculate) the displacement of the vibrating body 200 based on the digital signal supplied from the reception ADC .

[0053] FIG. 4 is a diagram illustrating an example of a chirp signal generated by the signal generation processing unit 11 of the signal processing unit 10. In FIG.

[0054] FIG. 4 shows the time structure of one frame when using the FCM (Fast-Chirp Modulation) method. FIG. 4 shows an example of a received signal in the FCM method. FCM is a method in which chirp signals shown as c1, c2, c3, c4, ..., cn in FIG. 4 are repeated at relatively short intervals (for example, equal to or longer than the round-trip time between the electromagnetic wave radar and the target, calculated from the maximum measured distance). In FCM, for convenience of signal processing of the received signal, transmission and reception processing is often performed by dividing the signal into subframe units as shown in FIG. 4.

[0055] In Fig. 4, the horizontal axis represents elapsed time, and the vertical axis represents frequency. In the example shown in Fig. 4, the signal generation processing unit 11 generates linear chirp signals whose frequencies change periodically and linearly. In Fig. 4, each chirp signal is represented as c1, c2, c3, c4, ..., cn. As shown in Fig. 4, the frequency of each chirp signal increases linearly with the passage of time.

[0056] In the example shown in FIG. 4, several chirp signals such as c1, c2, c3, c4, ..., cn are included in one subframe. That is, subframe 1 and subframe 2 shown in FIG. 4 are each configured to include several chirp signals such as c1, c2, c3, c4, ..., cn. Also, in the example shown in FIG. 4, several subframes such as subframe 1, subframe 2, ..., subframe N are included in one frame (1 frame). That is, 1 frame shown in FIG. 4 is configured to include N subframes. Also, 1 frame shown in FIG. 4 may be frame 1, followed by frame 2, frame 3, ..., etc. Each of these frames may be configured to include N subframes, just like frame 1. Also, a frame interval of a predetermined length may be included between frames. One frame shown in FIG. 4 may be, for example, 30 to 50 milliseconds long.

[0057] In the detection device 1 according to one embodiment, the signal generation processing unit 11 may generate a transmission signal as any number of frames. Also, some chirp signals are omitted from the illustration in Fig. 4. In this manner, the relationship between time and frequency of the transmission signal generated by the signal generation processing unit 11 may be stored as various setting parameters in, for example, a storage unit of the signal processing unit 10.

[0058] In this way, the detector 1 according to one embodiment may transmit a transmission signal consisting of subframes each including a plurality of chirp signals. Also, the detector 1 according to one embodiment may transmit a transmission signal consisting of a frame each including a predetermined number of subframes.

[0059] In the following description, the detection device 1 will be described as transmitting a transmission signal having a frame structure as shown in FIG. 4. However, the frame structure as shown in FIG. 4 is merely an example, and for example, the number of chirp signals included in one subframe may be arbitrary. That is, in one embodiment, the signal generation processing unit 11 may generate subframes including any number (for example, any plural number) of chirp signals. Also, the subframe structure as shown in FIG. 4 is merely an example, and for example, the number of subframes included in one frame may be arbitrary. That is, in one embodiment, the signal generation processing unit 11 may generate a frame including any number (for example, any plural number) of subframes. The signal generation processing unit 11 may generate signals of different frequencies. The signal generation processing unit 11 may generate multiple discrete signals, each having a frequency f with a different bandwidth.

[0060] Fig. 5 is a diagram showing, in another aspect, part of the subframe shown in Fig. 4. Fig. 5 shows each sample of the received signal obtained by receiving the transmitted signal shown in Fig. 4 as a result of 2D-FFT (Two Dimensional Fast Fourier Transform) processing performed by the received signal processing unit 12 (Fig. 3) of the signal processing unit 10.

[0061] As shown in Fig. 5, chirp signals c1, c2, c3, c4, ..., cn are stored in each subframe, such as subframe 1, ..., subframe N. In Fig. 5, each chirp signal c1, c2, c3, c4, ..., cn is composed of samples represented by squares arranged in the horizontal direction. The received signal shown in Fig. 5 is subjected to 2D-FFT, CFAR, and / or integrated signal processing of each subframe by the received signal processing unit 12 shown in Fig. 3.

[0062] FIG. 6 is a diagram showing an example of a point cloud calculated on a range-Doppler (distance-velocity) plane as a result of 2D-FFT, CFAR, and integrated signal processing of each subframe being performed in the received signal processing unit 12 shown in FIG. 3.

[0063] In FIG. 6, the horizontal direction represents range and the vertical direction represents velocity. The filled-in squares s1 in FIG. 6 represent point clouds indicating signals that exceed the CFAR threshold. The unfilled squares s2 in FIG. 6 represent bins (2D-FFT samples) without point clouds that do not exceed the CFAR threshold. The point clouds on the range-Doppler plane calculated in FIG. 6 have their azimuths from the radar calculated by direction estimation, and their positions and velocities on a two-dimensional plane are calculated as point clouds indicating an object such as the vibrating body 200. Here, the direction estimation may be calculated using a beamformer and / or a subspace method. Representative subspace method algorithms include MUSIC (MUltiple SIgnal Classification) and ESPRIT (Estimation of Signal Parameters via Rotation Invariance Technique).

[0064] Fig. 7 is a diagram showing an example of the result of the reception signal processing unit 12 converting the point cloud coordinates from the range-Doppler plane shown in Fig. 6 to the XY plane after performing direction estimation. The XY plane shown in Fig. 7 may be the same as the XY plane shown in Fig. 2. As shown in Fig. 7, the reception signal processing unit 12 can plot the point cloud PG on the XY plane. Here, the point cloud PG is made up of points P. Furthermore, each point P has an angle A and a radial velocity Vr in polar coordinates.

[0065] The received signal processing unit 12 detects an object present within the range where the transmitted wave is transmitted, based on at least one of the results of the 2D-FFT and the angle estimation. The received signal processing unit 12 may perform object detection by, for example, clustering processing based on the estimated distance information, speed information, and angle information. Known algorithms used for clustering data include DBSCAN (Density-based spatial clustering of applications with noise). This is an algorithm that performs clustering based on density. In the clustering processing, for example, the average power of points constituting the detected object may be calculated. The distance information, speed information, angle information, and power information of the object detected by the received signal processing unit 12 may be supplied to the electronic device 100, for example, via a communication interface.

[0066] As described above, the detection device 1 may include a transmitting antenna (transmitting antenna array 24), a receiving antenna (receiving antenna array 31), and a signal processing unit 10. The transmitting antenna array 24 transmits a transmission wave, for example, an electric wave. The receiving antenna array 31 receives a reflected wave of the transmission wave. The signal processing unit 10 then detects an object (such as the vibrating body 200) that reflects the transmission wave based on the transmission signal transmitted as the transmission wave and the reception signal received as the reflected wave.

[0067] Next, estimation of the direction of an incoming wave (incoming reflected wave) by the antenna array of the detector 1 according to one embodiment will be further described.

[0068] 8 is a diagram illustrating the configuration of the receiving antenna array 31 of the detector 1 according to one embodiment and the principle of estimating the direction of an incoming wave by the receiving antenna array 31. FIG. 8 shows an example of reception of radio waves by the receiving antenna array 31.

[0069] As shown in Figure 8, the receive antenna array 31 may be a linear arrangement of sensors such as receive antennas. As shown in Figure 8, in one embodiment, the receive antenna array 31 may include multiple receive antennas arranged in a linear arrangement. In Figure 8, the receive antenna array 31 includes antennas x1, x2, x3, ..., x M In the figure, multiple antennas such as those shown in the figure are represented by small circles. The receiving antenna array 31 may be composed of any number of antennas. As shown in FIG. 8, the multiple antennas constituting the receiving antenna array 31 are arranged at an array pitch d. A sensor array in which sensors (antennas, ultrasonic transducers, microphones, etc.) corresponding to various physical waves are arranged in an array is also called a uniform linear array (ULA). As shown in FIG. 8, physical waves (electromagnetic waves, sound waves, etc.) arrive from various directions, such as A1 and A2. Here, A1 and A2 may be the angles of arrival described above. In this way, a sensor array such as the receiving antenna array 31 can estimate the direction of arrival (angle of arrival) by utilizing the phase difference that occurs in the measurements between sensors depending on the direction of arrival of the physical wave. This method of estimating the direction of arrival of a wave is also referred to as angle of arrival estimation or direction of arrival (DoA).

[0070] In the detection device 1 according to one embodiment, at least one of the transmitting antenna array 24 and the receiving antenna array 31 may be configured with multiple antennas arranged in a line. This allows, for example, millimeter-wave radar to appropriately narrow the directivity when transmitting and receiving radio waves. When transmitting a transmitted wave, the direction of the transmitted beam is often controlled by a beamformer. On the other hand, when receiving a reflected wave, the direction of arrival of the reflected wave is often estimated by a subspace method (such as the above-mentioned MUSIC and ESPRIT) rather than a beamformer. In the beamformer and subspace method, in a ULA such as that shown in FIG. 8, a phase difference occurs in the measurements between sensors depending on the direction of arrival of electromagnetic waves arriving from various directions. Therefore, the phase difference can be used to estimate the direction of arrival of the reflected wave.

[0071] Next, the estimation of angles of the incoming waves in two directions by the antenna array of the detector 1 according to one embodiment will be further described.

[0072] FIG. 9 is a diagram showing an example of an antenna arrangement for estimating directions of arrival at two orthogonal angles.

[0073] As shown in FIG. 9, in the detection device 1 according to one embodiment, the transmitting antenna array 24 and / or the receiving antenna array 31 may include an array of a plurality of patch antenna units.

[0074] In the transmitting antenna array 24 shown in FIG. 9, one patch antenna unit may be configured to include a plurality of elements electrically connected in the direction 1 shown in the figure. In each patch antenna unit, the plurality of elements may be electrically connected by wiring such as a stripline on a substrate. In each patch antenna unit, the plurality of elements are spaced apart at intervals d that are shorter than half the wavelength λ of the transmitting wave. 1,t 9, each patch antenna unit may have any number of elements greater than or equal to two electrically connected together.

[0075] 9, the transmitting antenna array 24 may be configured by arraying a plurality of patch antenna units in the direction 2 shown in the figure. The patch antenna units are spaced apart at intervals d, which are shorter than half the wavelength λ of the transmitting wave. 2,t In one embodiment, the transmit antenna array 24 may include any number of patch antenna units greater than or equal to two.

[0076] As shown in Fig. 9, in one embodiment, the receiving antenna array 31 may be configured by changing the arrangement of the multiple elements in the transmitting antenna array 24. That is, in the receiving antenna array 31 shown in Fig. 9, one patch antenna unit may be configured to include multiple elements electrically connected in the direction 2 shown in the figure. In each patch antenna unit, the multiple elements may be electrically connected by wiring such as a stripline on a substrate. In each patch antenna unit, the multiple elements are spaced apart at intervals d that are shorter than half the wavelength λ of the transmission wave. 2,s 9, each patch antenna unit may have any number of elements greater than or equal to two electrically connected together.

[0077] 9, the receiving antenna array 31 may be configured by arraying a plurality of patch antenna units in a direction 1 shown in the figure. The patch antenna units are spaced apart at intervals d, which are shorter than half the wavelength λ of the transmission wave. 1,s In one embodiment, the receive antenna array 31 may include any number of patch antenna units greater than or equal to two.

[0078] The elements included in the transmitting antenna array 24 and the receiving antenna array 31 may all be arranged on the same plane (for example, on the surface layer of the same substrate). The transmitting antenna array 24 and the receiving antenna array 31 may also be arranged close to each other (monostatic). Furthermore, directions 1 and 2 shown in Figure 9 may be geometrically orthogonal to each other.

[0079] The transmitting antenna array 24 and the receiving antenna array 31 shown in FIG. 9 can appropriately narrow the directivity of each of the transmitting antennas and the receiving antennas. Furthermore, by using the transmitting antenna array 24 shown in FIG. 9 to control the direction of transmission of each transmission wave (transmission signal) at each timing of transmission, a beamformer for direction 2 shown in FIG. 9 can be realized. Furthermore, by using the receiving antenna array 31 shown in FIG. 9, the arrival direction of the reflected wave can be estimated for direction 1 shown in FIG. 9. In this way, it is possible to estimate the arrival direction of the reflected wave for two angles that are substantially orthogonal to each other. Therefore, it is possible to obtain a point cloud representing an object such as the vibrating body 200 in three dimensions.

[0080] 10 is a block diagram showing the functional configuration of the electronic device 100 according to an embodiment. An example of the configuration of the electronic device 100 according to an embodiment will be described below.

[0081] 10, the electronic device 100 according to an embodiment may include a processor 102, a display unit 104, a storage unit 106, a communication unit 108, and an operation unit 110. The electronic device 100 according to an embodiment may not include some of the functional units shown in FIG. 10, or may include functional units other than those shown in FIG.

[0082] The processor 102 performs various functions for controlling and / or managing the electronic device 100. The processor 102 may include at least one processor, such as a central processing unit (CPU), to provide control and processing power for performing the various functions. The processor 102 may be implemented as a single processor, as several processors, or as individual processors. Here, the "processor" may be implemented as a single integrated circuit. An integrated circuit is also called an IC (Integrated Circuit). The "processor" may also be implemented as multiple integrated circuits and discrete circuits connected to each other in a communicative manner. The "processor" may also be implemented based on various other known technologies.

[0083] In one embodiment, the processor 102 may be configured as, for example, a CPU and a program executed by the CPU. The program executed by the processor 102 and the results of the processing executed by the processor 102 may be stored in the storage unit 106. Furthermore, the results of the processing executed by the processor 102 may be reflected in the control of the electronic device 100, the detection device 1, and / or the signal generator 400.

[0084] The display unit 104 may be any display device, such as a liquid crystal display (LCD), an organic electroluminescence (EL) display (organic electroluminescence) panel, or an inorganic electroluminescence (EL) display. The display unit 104 may display various types of information, such as characters, figures, or symbols. The display unit 104 may also display various GUI objects, such as a pointer, and icon images, to prompt the user to perform an operation. Various types of data required for display on the display unit 104 may be supplied from, for example, the processor 102 or the memory unit 106. The display unit 104 may also be configured to include a backlight, etc., as appropriate.

[0085] Furthermore, the electronic device 100 according to an embodiment may include, instead of the display unit 104 or in addition to the display unit 104, a speaker or the like that conveys various pieces of information by voice to the user operating the electronic device 100.

[0086] In one embodiment, the display unit 104 may display, for example, the results of processing executed by the processor 102. The display unit 104 may also display, for example, characters or images stored in the storage unit 106. The display unit 104 may also display, for example, characters or images based on data received via the communication unit 108. The display unit 104 may also display, for example, information input from the operation unit 110.

[0087] The storage unit 106 stores various pieces of information acquired from the processor 102, the communication unit 108, and the like. In one embodiment, the storage unit 106 may store, for example, information input by a user. The storage unit 106 also stores programs (e.g., application software) executed by the processor 102. The storage unit 106 may also store various pieces of data, such as calculation results by the processor 102. The storage unit 106 may also include a work memory used when the processor 102 operates. The storage unit 106 may be configured, for example, by a semiconductor memory or a magnetic disk, but is not limited to these, and may be any storage device. For example, the storage unit 106 may be a memory such as a memory card inserted into the electronic device 100 according to one embodiment. The storage unit 106 may also be an internal memory of a CPU used as the processor 102.

[0088] The communication unit 108 can realize various functions including wireless communication. The communication unit 108 may realize communication using various communication methods, such as LTE (Long Term Evolution), 4G, or 5G. The communication unit 108 may include, for example, a modem whose communication method is standardized by ITU-T (International Telecommunication Union Telecommunication Standardization Sector). The communication unit 108 may also realize wireless communication using various methods, such as Wi-Fi or Bluetooth (registered trademark). The communication unit 108 may wirelessly communicate with a communication unit of an external device, such as the detection device 1, via a network. The communication unit 108 may also wirelessly communicate with a communication unit of an external device, such as an external server or a cloud server, via a network, for example, via an antenna. In one embodiment, the communication unit 108 may receive various information, such as detection results by the detection device 1, from the detection device 1. The information received by the communication unit 108 may be supplied to, for example, the processor 102 and / or the storage unit 106. Additionally, the information transmitted from the communication unit 108 may be provided by the processor 102 and / or the memory unit 106, for example.

[0089] The various types of information transmitted and received by the communication unit 108 may be stored in, for example, the storage unit 106. The communication unit 108 may be configured to include, for example, an antenna for transmitting and receiving radio waves and an appropriate RF unit. The communication unit 108 may be configured using known technology for performing wireless communication. The communication unit 108 may also be an interface for wired communication between the electronic device 100 and other devices. In this case, for example, the communication unit 108 may be a connector or terminal for wired connection.

[0090] The operation unit 110 detects, for example, an operation by a user as an input. The operation unit 110 may be configured with an input device such as a keyboard. The operation unit 110 may be any input device used by a user to perform an operation, such as keys (physical keys) like a keyboard, buttons (physical buttons), switches (mechanical switches), and / or pointing devices such as a mouse or trackball. In one embodiment, the operation unit 110 may be any known input device. An operation signal (input signal) detected by the operation unit 110 may be supplied to, for example, the processor 102 and / or the memory unit 106.

[0091] The operation unit 110 may also be an input device such as a touch panel or a touch sensor. In this case, the operation unit 110 may employ various types of touch panels, such as a resistive type, a capacitive type, or an optical type.

[0092] In one embodiment, the display unit 104 may be configured as, for example, a touchscreen display together with the operation unit 110. In this case, the touchscreen display may include, as the display unit 104, a display device such as a liquid crystal display or an organic EL display. In addition, in this case, the touchscreen display may include, as the operation unit 110, a touch sensor or a touch panel that detects whether or not a user has made a touch and the position of the touch. In such a configuration, for example, keys such as a numeric keypad or icons can be displayed as objects on the display unit 104, and the operation of the operator (user) touching the object can be detected by the operation unit 110.

[0093] At least a part of each functional unit constituting the electronic device 100 according to an embodiment may be constituted by specific means in which software and hardware resources work together.

[0094] Next, the operation of the electronic device 100 and the detection device 1 according to an embodiment when detecting vibrations of the object 200 excited by the excitation source 300 will be described.

[0095] An electronic device 100 according to an embodiment can measure vibrations of an object 200 at multiple points using a detection device 1 such as a radar sensor, and detect the shape of the vibration mode of the object 200. As shown in FIG. 1 , for example, if a damaged portion 210 exists in the object 200, a change in the shape of the vibration mode may be observed. The electronic device 100 according to an embodiment can be useful in diagnosing whether or not there is a high possibility that an abnormality exists in a structure such as the object 200, based on such a change in the shape of the vibration mode.

[0096] On the other hand, when measuring vibration at many points, installing sensors for each measurement point increases the cost and / or labor burden. Therefore, when measuring vibration at multiple points, it is more convenient to use a single sensor and move it between multiple measurement points, as shown in Figure 1.

[0097] To experimentally obtain the vibration mode of a structure such as the object 200, it is necessary to measure vibrations while the structure is excited in some way. The electronic device 100 and the detection device 1 according to an embodiment detect the vibration of the object 200 while acoustically exciting the object 200 with the excitation source 300. When acoustically excited in this manner, a structure such as the object 200 is generally expected to vibrate steadily. When the structure vibrates steadily in response to excitation by the excitation source 300, the deformation state of the structure such as the object 200 due to the vibration corresponds one-to-one to the phase of the vibration waveform of the excitation source 300 (hereinafter also referred to as "excitation waveform").

[0098] FIG. 11 is a diagram showing an example of the correspondence between the vibration waveform of the vibration source 300 and the deformation state (due to vibration) of the object 200. The upper part of FIG. 11 shows the vibration waveform of the vibration source 300 (i.e., the excitation waveform). The vertical axis of the upper part of FIG. 11 represents the amplitude of the excitation waveform, and the horizontal axis of the upper part of FIG. 11 represents time. The lower part of FIG. 11 shows the deformation state of the object 200 at several points in time shown in the upper part of FIG. 11. For example, the lower part of FIG. 11 may show the entire object 200 as seen from a predetermined direction. Furthermore, for example, the lower part of FIG. 11 may show the deformation of the object 200 in a somewhat exaggerated manner.

[0099] At time u1 of the excitation waveform shown in the upper part of Fig. 11, the object 200 is in a deformed state as shown in the lower part (u1) of Fig. 11. At time u2 of the excitation waveform shown in the upper part of Fig. 11, the object 200 is in a deformed state as shown in the lower part (u2) of Fig. 11. At time u3 of the excitation waveform shown in the upper part of Fig. 11, the object 200 is in a deformed state as shown in the lower part (u3) of Fig. 11. As shown in Fig. 11, it can be seen that the deformation states (due to vibration) of the object 200 are different at times when the excitation waveform phases are different.

[0100] Similar to FIG. 11, FIG. 12 is a diagram showing an example of the correspondence between the vibration waveform of the vibration source 300 and the deformation state (due to vibration) of the object 200. The upper part of FIG. 12 shows the vibration waveform of the vibration source 300 (i.e., the excitation waveform). The vertical axis of the upper part of FIG. 12 represents the amplitude of the excitation waveform, and the horizontal axis of the upper part of FIG. 12 represents time. The lower part of FIG. 12 shows the deformation state of the object 200 at several points in time shown in the upper part of FIG. 12. For example, the lower part of FIG. 12 may show the entire object 200 as viewed from a predetermined direction. Furthermore, for example, the lower part of FIG. 12 may show the deformation of the object 200 in a somewhat exaggerated manner.

[0101] At time u4 of the excitation waveform shown in the upper part of Fig. 12, the object 200 is in a deformed state as shown in the lower part (u4) of Fig. 12. At time u5 of the excitation waveform shown in the upper part of Fig. 12, the object 200 is in a deformed state as shown in the lower part (u5) of Fig. 12. At time u6 of the excitation waveform shown in the upper part of Fig. 12, the object 200 is in a deformed state as shown in the lower part (u6) of Fig. 12. As shown in Fig. 11, it can be seen that at the times when the excitation waveforms have the same phase, the deformation states (due to vibration) of the object 200 are also in the same state.

[0102] From the above, it can be seen that for a steadily vibrating structure, the vibration mode of the structure can be reproduced from data of each measurement point acquired at different times. For this reason, electronic device 100 according to one embodiment synchronizes the phase of the excitation waveform between the data acquired as a result of measurement at each time point, i.e., searches for a measurement time point at which the phase of the excitation waveform becomes the same.

[0103] In this way, one possible method for synchronizing the phase of the excitation waveform is to acquire time labels between the excitation waveform and the measurement waveform of the detection wave (transmission wave) transmitted from the detection device 1 while time synchronizing them. However, developing a system that realizes such a method requires significant cost and / or effort. Therefore, the electronic device 100 according to one embodiment utilizes the fact that the time interval between measurements by the detection device 1 is constant, and continuously vibrates the object 200 while continuously acquiring data by the detection device 1. In this way, the electronic device 100 according to one embodiment can perform time synchronization between each measurement point.

[0104] Generally, experimental analysis of vibration modes requires time synchronization between the excitation source 300 and the detection device 1. However, developing such a system requires cost and / or effort. According to the electronic device 100 of one embodiment, time synchronization between the excitation source 300 and the detection device 1 is not required. Therefore, according to the electronic device 100 of one embodiment, vibrations of the object 200 can be detected easily with good accuracy by transmitting and receiving waves, and such a measurement system can be constructed inexpensively.

[0105] FIG. 13 is a diagram visually showing an example of the temporal correspondence between continuous data acquired by the detection device 1 and the excitation waveform.

[0106] The upper part of Fig. 13 shows the vibration waveform (i.e., excitation waveform) of the vibration source 300, similar to the upper parts of Fig. 11 and Fig. 12. The vertical axis of the upper part of Fig. 12 represents the amplitude of the excitation waveform, and the horizontal axis of Fig. 12 represents time. The lower part of Fig. 13 shows continuous data acquired by the detection device 1.

[0107] The detection device 1 according to one embodiment performs measurements (detections) at regular, equal intervals. That is, in the detection device 1 according to one embodiment, the time interval from the first detection to the second detection, the time interval from the second detection to the third detection, ..., the time interval from the nth detection to the (n+1)th detection are all the same. A radar sensor assumed as the detection device 1 according to one embodiment performs measurements (detections) at regular, equal intervals. Furthermore, various vibration sensors other than radar sensors also generally perform measurements (detections) at regular, equal intervals.

[0108] The lower part of Figure 13 shows the continuous data measured (acquired) by the detection device 1, plotted as white circles (○). The horizontal intervals (i.e., time intervals) between the continuous data (white circles (○)) acquired by the detection device 1 are all the same. The horizontal intervals between the white circles (○) shown in the lower part of Figure 13 correspond to the time intervals of measurements by the detection device 1.

[0109] If the frequency of the excitation waveform shown in FIG. 13 is f, the data acquired at a time difference of n / f (where n is an integer) from any data (white circle symbol (○)) measured by the detection device 1 has the same phase (in-phase) of the excitation waveform. In FIG. 13, if the time interval from time t1 to time t2 is represented as δT1, it can be expressed as δT1=n1 / f (where n1 is an integer). Similarly, in FIG. 13, if the time interval from time t2 to time t3 is represented as δT2, it can be expressed as δT2=n2 / f (where n2 is an integer).

[0110] 13, the excitation waveforms are all in the same phase at time t1, time t2, and time t3. Therefore, it can be considered that the data detected by the detection device 1 at time t1, time t2, and time t3 indicate the same deformation state of the object 200. Using this principle, the electronic device 100 according to one embodiment can synchronize the phase of the excitation waveform between the data acquired as a result of measurement at each time, i.e., can find a measurement time at which the phase of the excitation waveform is the same.

[0111] In this way, the vibration source 300 according to one embodiment continuously vibrates the object 200. In addition, in such a situation, the detection device 1 according to one embodiment continuously acquires (measures) the vibrations of the object 200 that is continuously vibrated.

[0112] Next, a description will be given of the operation of the electronic device 100 according to an embodiment. Fig. 14 is a flowchart illustrating a procedure including an operation of synchronizing the phase of the excitation waveform, which is performed by the electronic device 100 according to an embodiment.

[0113] As shown in step S11 of FIG. 14, first, the resonant frequency and vibration mode of the object 200 to be inspected are logically analyzed.

[0114] In the operation of the electronic device 100 according to the embodiment described below, it is necessary to know in advance what kind of resonant frequency the object 200 to be inspected has and what kind of vibration mode shape exists at that time. For this purpose, for example, a simulation using the finite element method (FEM) or the like may be performed.

[0115] 15A, 15B, and 15C are diagrams showing the shape of each mode calculated by using FEM for the resonance modes of the plate-shaped object 200. Fig. 15A shows the shape of the fundamental vibration mode among the vibration modes of the object 200. Fig. 15B shows the shape of the second harmonic vibration mode among the vibration modes of the object 200. Fig. 15C shows the shape of the third harmonic vibration mode among the vibration modes of the object 200.

[0116] In one embodiment, the simulation in step S11 does not necessarily have to be performed. For example, since the structure of the object 200 is simple, it may be easy to calculate the resonance mode of the object 200 by formulating an equation of motion. Also, it may be the case that the vibration mode of the object 200 is known by using another method. In such cases, it is not necessarily necessary to perform the simulation in step S11.

[0117] Next, as shown in step S12 of FIG. 14, the resonance frequency of the object 200 is measured (actually measured).

[0118] In most cases, the resonant frequency of the object 200 obtained by simulation does not exactly match the actual resonant frequency of the object 200. The procedure of step S12 does not necessarily have to be performed if the resonant frequency of the object 200 is known, for example, by simulation. However, if possible, the resonant frequency of the actual object 200 may be measured by the following procedure.

[0119] In step S12, the object 200 may be excited by the excitation source 300. In this case, the frequency characteristics of the signal supplied from the signal generator 400 to the excitation source 300 may be such that the frequency band to be measured is sufficiently included. Such a signal may be, for example, a signal whose frequency changes over time, such as a chirp signal, or a signal based on random noise. Alternatively, the object 200 may be excited by gradually changing the frequency of the signal based on a sine wave having a constant frequency.

[0120] In the following example, we will explain the case where a chirp signal whose frequency increases linearly with time (linear chirp signal) is used. A linear chirp signal can be expressed as the following equation (1) using an initial phase Φ0.

[0121]

number

[0122] In one embodiment, the signal generator 400 may supply a linear chirp signal as shown in the above equation (1) to the vibration source 300. This allows the vibration source 300 to vibrate the object 200 based on this signal. In this situation, the vibration amplitude of the object 200 may be measured using the detection device 1 according to one embodiment.

[0123] Fig. 16 is a diagram showing a vibration waveform used when the vibration source 300 vibrates the object 200. The vertical axis of Fig. 16 represents the amplitude of the vibration waveform, and the horizontal axis of Fig. 16 represents time. As shown in Fig. 16, the vibration source 300 may use, for example, a linear chirp signal when vibrating the object 200.

[0124] Fig. 17 is a diagram showing an example of a waveform detected (measured) by the detector 1 when the object 200 is vibrated using the excitation waveform shown in Fig. 16. The vertical axis of Fig. 17 represents the amplitude of the waveform detected (measured) by the detector 1, and the horizontal axis of Fig. 17 represents time. As shown in Fig. 17, the waveform measured by the detector 1 has a time t0 at which the vibration amplitude reaches a peak. In this case, the resonant frequency of the object 200 can be determined as the frequency f0 of the chirp signal at time t0.

[0125] The object 200 may have multiple resonant frequencies depending on its material and / or shape. Furthermore, depending on the vibration mode of the object 200, the location where the measurement is performed may be a node. Therefore, the final resonant frequency may be determined after repeatedly identifying the resonant frequency at multiple points (positions) on the object 200. However, if the shape of the object 200 is simple and the vibration mode is easy to estimate, or if the vibration mode and resonant frequency of the object 200 are estimated by simulation or the like, such identification of the resonant frequency may not be necessary. The following description will be given assuming that the mode in which the measurement is performed is a vibration mode corresponding to a single resonant frequency.

[0126] 14, conditions for measuring the vibration of the object 200 by the detector 1 are set in consideration of the vibration mode of the object 200 and the antenna directivity of the detector 1. In step S13, conditions for measuring the vibration of the object 200 by the detector 1 may be determined in consideration of the vibration mode analyzed in step S11.

[0127] The applicant also discovered that in a radar sensor, the detection area of ​​an object is determined by the directivity of the antenna, and vibrations within that detection range are averaged. As the applicant has already filed a patent application for this content (Patent Application No. 2023-199461, filed on October 27, 2023), further detailed explanation will be omitted.

[0128] Furthermore, the spatial vibration period may vary depending on the vibration mode of the object 200 being measured. For this reason, it is desirable to narrow the intervals between measurement points (positions where the detector 1 measures) when measuring the vibration mode of an object 200 with a shape having a shorter vibration period. As a guideline, the detection area (measurement area) of the detector 1 may be set to half a wavelength or less. In this case, measurements may be taken at least at two or more locations per wavelength. By doing so, the shape of the vibration mode can be identified well.

[0129] Next, as shown in step S14 of FIG. 14, the object 200 is vibrated by the vibration source 300, and the detected vibration of the object 200 is measured by the detection device 1.

[0130] Step S14 may be executed as follows: First, the signal generator 400 supplies a sine wave signal of the resonant frequency determined in step S12 to the vibration source 300. As a result, the vibration source 300 vibrates the object 200. In this state, the detection device 1 detects (measures) the vibration of the object 200 according to the conditions set in step S13.

[0131] Here, it is desirable that the vibration mode assumed under the measurement conditions of the object 200 is sufficiently excited in the object 200. For this reason, it is desirable that the intensity with which the vibration source 300 vibrates the object 200 is set appropriately. As shown in FIG. 1 , in a system according to one embodiment, there may be one detection device 1 that measures the vibration of the object 200. Furthermore, the detection device 1 may continue to continuously detect data while measuring the vibration of the object 200. Furthermore, during this time, the vibration source 300 may continue to continuously vibrate the object 200.

[0132] For example, in the device configuration shown in FIG. 1, when the vibration of the object 200 is measured by the detection device 1, the result shown in FIG. 13 may be obtained.

[0133] For example, during the time period from time w1 to time w2 shown in Fig. 13, the detection device 1 may detect vibrations of the object 200 while remaining stationary at position 1 shown in Fig. 1. During the time period from time w2 to time w3 shown in Fig. 13, the detection device 1 may be in a state of moving from position 1 to position 2 shown in Fig. 1. During the time period from time w2 to time w3 shown in Fig. 13, the detection device 1 may not be able to detect data constituting a valid waveform, or may detect data containing noise.

[0134] 13, the detection device 1 may detect vibrations of the object 200 while stationary at position 2 shown in FIG. 1. From time w4 to time w5 shown in FIG. 13, the detection device 1 may be moving from position 2 to position 3 shown in FIG. 1. From time w4 to time w5 shown in FIG. 13, the detection device 1 may not be able to detect data constituting a valid waveform, or may detect data containing noise. From time w5 to time w6 shown in FIG. 13, the detection device 1 may detect vibrations of the object 200 while stationary at position 3, which is next to position 2 shown in FIG. 1.

[0135] Next, as shown in step S15 of FIG. 14, the electronic device 100 may synchronize the time points of the measurement results at each position. When the intended excitation waveform is excited in the object 200, as shown in FIG. 11, the displacement of the surface of the object 200 corresponds one-to-one to the phase of the excitation waveform. Therefore, the electronic device 100 may extract displacement data of each measurement point corresponding to a certain phase of the excitation waveform from the measurement waveforms of each measurement point measured at different times in step S14. The electronic device 100 may generate data indicating the shape of the vibration mode from the displacement data extracted in this manner.

[0136] Here, if the frequency of the excitation waveform is f, the period can be expressed as 1 / f. That is, for any natural number n, the phase of the excitation waveform is the same at time points n / f apart. Therefore, in the detected data shown in FIG. 13, the electronic device 100 may search for time points (time points t1, t2, t3, ... in FIG. 13) at which the time difference of the detector 1 is an integer multiple of the vibration period 1 / f of the target object 200 (for example, n1, n2, ... in the figure). Once the operation of step s15 is completed, the electronic device 100 can synchronize the phase of the excitation waveform between the data acquired as a result of measurement at each time point.

[0137] Next, as shown in step S16 of FIG. 14, the electronic device 100 may display the instantaneous deformation of the object 200 as a graph or a 3D model on the display unit 104, for example.

[0138] In step S16, the electronic device 100 may perform the following operation: That is, the electronic device 100 may generate a diagram in which the waveforms measured by the detection device 1 at each of the time points t1, t2, t3, ... obtained in step S15 are arranged by measurement position, and may display the diagram on the display unit 104, for example.

[0139] FIG. 18 is a diagram showing an example of time synchronization of waveforms measured at each measurement position. The upper part of FIG. 18 shows continuous data acquired by the detection device 1, similar to the lower part of FIG. 13. The upper part of FIG. 18 shows a waveform detected by the detection device 1 by smoothly connecting the plotted points of the continuous data acquired by the detection device 1. The vertical axis of the upper part of FIG. 18 represents the amplitude of the detected waveform, and the horizontal axis of the upper part of FIG. 18 represents time. The lower part of FIG. 18 shows the displacement of the object 200 corresponding to the detected waveform shown in the upper part of FIG. 18. The vertical axis of the lower part of FIG. 18 represents the displacement of the object 200, and the horizontal axis of the lower part of FIG. 18 represents the position of the object 200. The lower part of FIG. 18 also shows, as examples, the displacement of the object 200 at time t4, which is before time t3 shown in the upper part of FIG. 18, and the displacement of the object 200 at an even further future time t5. The electronic device 100 may display a graph such as that shown in FIG. 18 on the display unit 104, for example.

[0140] As shown in FIG. 18, when the waveforms detected by the detector 1 at each time point are displayed side by side for each measurement position, the instantaneous deformation at each measurement position when the excitation waveform is at a certain phase can be easily recognized.

[0141] In addition, in one embodiment, for example, the time points t1+ΔT, t2+ΔT, t3+ΔT, ... at which a certain time offset ΔT has elapsed from the time points t1, t2, t3, ... shown in Figure 18 may also be illustrated in a similar manner to that shown in Figure 18.

[0142] 19A, 19B, 19C, and 19D are diagrams showing examples of changes in the overall vibration displacement of the object 200 over time. Similar to the diagram shown in the lower part of FIG. 18, FIG. 19A shows the displacement of the object 200 at each measurement position at instants of the same phase (time points t1, t2, t3, ...). FIG. 19B shows the displacement of the object 200 at each measurement position at instants (time points t1+ΔT, t2+ΔT, t3+ΔT, ...) when a certain offset time ΔT has elapsed since the instant shown in FIG. 19A. FIG. 19C shows the displacement of the object 200 at each measurement position at instants (time points t1+2ΔT, t2+2ΔT, t3+2ΔT, ...) when a certain offset time ΔT has elapsed since the instant shown in FIG. 19B. 19D is a diagram showing the displacement of the object 200 at each measurement position at a certain offset time ΔT (times t1+3ΔT, t2+3ΔT, t3+3ΔT, ...) after the time shown in FIG. 19C. The electronic device 100 may display graphs such as those shown in FIGS. 19A to 19D on the display unit 104, for example.

[0143] Furthermore, in one embodiment, electronic device 100 may display, on display unit 104, for example, a 3D model as a representation of the deformation of object 200. In this way, the deformation of the entire object 200 can be represented in a visually easy-to-understand manner.

[0144] As described above, electronic device 100 according to one embodiment can synchronize the phase of the excitation waveform between data acquired as a result of measurement at each point in time. Therefore, electronic device 100 according to one embodiment can easily detect the vibration of the vibrating body with good accuracy by transmitting and receiving waves.

[0145] (Vibration detection method) Next, a method for detecting vibrations of a vibrating body with high accuracy using the detection device 1 and / or the electronic device 100 according to an embodiment will be further described.

[0146] In one embodiment, to detect the vibration mode of a structure such as the object 200, the vibration of the entire structure such as the object 200 may be detected, and the deformation of each part due to the vibration may be captured. When detecting vibration of a structure such as the object 200 using the detection device 1 and / or the electronic device 100 according to one embodiment, the following points should be noted. First, when employing a technology such as a radar sensor, it should be noted that the detection device 1 has the property of acquiring vibrations by averaging within a certain field of view determined by the antenna directivity. The applicant mentioned this point in the aforementioned patent application (Japanese Patent Application No. 2023-199461, filed October 27, 2023). Next, it should be noted that the physical wavelength due to vibration of a structure such as the object 200 varies depending on the vibration mode. These points will be further explained below.

[0147] When the detector 1 employs a technology such as a radar sensor, it has angular directionality, and therefore has the property of receiving reflected waves within a certain range within a certain angle of view (field of view) θ when viewed from the antenna.

[0148] 20A and 20B are diagrams showing an example of a field of view θ of the detector 1 according to one embodiment. As shown in FIGS. 20A and 20B, the detector 1 has a detection range with a certain angle of view (field of view) θ relative to the object 200. The detector 1 transmits detection waves, such as radio waves, toward the object 200. In FIG. 20A, the detection waves irradiated from the detector 1 toward the object 200 are shown as a measurement region (detection region) R1. Similarly, in FIG. 20B, the detection waves irradiated from the detector 1 toward the object 200 are shown as a measurement region (detection region) R2.

[0149] 20A and 20B, when the viewing angle θ of the detector 1 is constant, the areas of the measurement region R1 and the measurement region R2 vary depending on the distance between the detector 1 and the object 200. As shown in FIG. 20A, when the distance D1 between the detector 1 and the object 200 is relatively short, the measurement region R1 is also relatively small. On the other hand, as shown in FIG. 20B, when the distance D2 between the detector 1 and the object 200 is relatively long, the measurement region R2 is relatively large. In other words, when the viewing angle θ from the detector 1 is constant, when the distance between the detector 1 and the object 200 is short, the measurement region on the object 200 is narrow, and when the distance between the detector 1 and the object 200 is long, the measurement region on the object 200 is wide.

[0150] Next, a description will be given of the relationship between the measurement area of ​​the detection device 1 and the shape change of the object 200. Figures 21A and 21B are diagrams showing an example of the measurement area of ​​the detection device 1 and the shape change of the object 200 according to one embodiment.

[0151] FIG. 21A shows that the measurement area R of the detection device 1 is relatively large compared to the shape change of the object 200. The measurement area R shown in FIG. 21A may be too large compared to the shape change of the object 200. The diameter (particularly the major axis Ra) of the measurement area R shown in FIG. 21A is far larger than the width of the object 200. As described above, the detection device 1 has the property of acquiring vibrations within a certain field of view by averaging them. Therefore, if the detection device 1 detects the vibrations of the object 200 by averaging them within the range of the measurement area R shown in FIG. 21A, for example, it may be difficult to accurately measure the vibration pattern of the object 200. Furthermore, the interval B between the detection areas R shown in FIG. 21A is wide compared to the shape change of the object 200. Therefore, in the state shown in FIG. 21A, it may be difficult for the detection device 1 to capture the overall deformation of the long, plate-shaped object 200.

[0152] 21B shows that the measurement area R of the detector 1 is smaller than the measurement area R shown in FIG. 21A relative to the shape change of the object 200. The diameter (particularly the major axis Ra) of the measurement area R shown in FIG. 21B is approximately the same as the width of the object 200. Furthermore, the interval B between the detection areas R shown in FIG. 21B is relatively narrow relative to the shape change of the object 200. Therefore, in the state shown in FIG. 21B, the detector 1 can easily capture the deformation of the long plate-shaped object 200 as a whole, and can easily obtain the vibration mode of the object 200. In the state shown in FIG. 21B, the measurement area and measurement points of the detector 1 are sufficiently small compared to the shape change due to the vibration mode of the object 200.

[0153] In consideration of the above considerations, the detection device 1 according to one embodiment may perform vibration detection as follows. (1) The distance D between the detector 1 and the object 200 may be set so that the shape of the expected vibration mode of the object 200 can be appropriately resolved. (2) The intervals between the measurement points of the object 200 measured by the detection device 1 may be set so that the vibration mode of the object 200 can be resolved appropriately.

[0154] FIG. 22 is a diagram illustrating parameter settings for vibration detection by the detection device 1 according to an embodiment. In one embodiment, the detection device 1 may perform measurement so that, in an assumed vibration mode shape, the half-width α of the detection wave (electromagnetic wave) beam falls within an equiphase surface (a region in which the direction of displacement from the vibration center of the object 200 is the same), as shown in FIG. 22 . The vibrating object 200 vibrates in a predetermined direction or in a direction opposite to the predetermined direction, centered on a certain reference point (for example, the vibration center shown in FIG. 22 ). The equiphase surface may also be defined as a portion of the vibrating body in which the displacement from the vibration center is directed in a predetermined direction. Generally, structures such as the object 200 do not always have simple vibration modes, such as a long, plate-shaped object as shown in FIG. 22 . Depending on the structure, for example, a vibration mode shape in which an equiphase surface and an antiphase surface are arranged in a patch pattern may also be considered. Therefore, in one embodiment, the distance D between the detection device 1 and the object 200 may be set so that the condition shown in the following equation (2) is satisfied. In equation (2), the diameter of the equiphase surface (the area in which the direction of displacement from the vibration center of the object 200 is the same) is L, and the half-width of the gain of the antenna that transmits the detection wave (electromagnetic wave) of the detection device 1 is α. D <L / 2tan(α / 2) (2)

[0155] In one embodiment, the detection device 1 may detect vibration of the object 200 by selecting a beam center such that an equiphase surface falls within the half-width of the beam irradiated by the antenna, according to the distance D from the object 200 that is set to satisfy the above formula (2). Furthermore, if the object 200 is a structure having a planar extension, the detection device 1 may detect vibration of the object 200 by satisfying the above-mentioned condition on all surfaces perpendicular to the direction in which the beam is irradiated. The applicant has confirmed that the vibration detection method as described above can detect vibration of a vibrating body such as the object 200 with good accuracy.

[0156] In one embodiment, the diameter L of the equiphase surface (the region in which the direction of displacement from the vibration center of the object 200 is the same) in the above equation (2) may be the spacing between multiple measurement points at which the detection device 1 detects (measures) the vibration of the object 200. The spacing between multiple measurement points is set to L in this way to sufficiently resolve and measure n-fold (n is a natural number) vibrations from the fundamental vibration of the vibration mode of the object 200 in the case of a long plate-like object. The concept of "spatial frequency" may be used to evaluate the scale of spatial changes in the vibration mode shape. This concept applies the frequency of a time-domain signal to real space. To analyze this spatial frequency without aliasing, the sampling theorem must be satisfied, just as with time-domain signals. The sampling theorem states that if measurements are performed at intervals that provide two or more measurement points per wavelength, the frequency components of the original signal can be completely reproduced. For a long plate-shaped object 200 such as that shown in Figures 15A to 15C, the sampling theorem is satisfied if the size is set to be equal to or less than L, which is the length of the equiphase surface (the area where the displacement direction is the same).

[0157] As described above, a method for detecting vibrations of an object 200 vibrating at a predetermined frequency (such as the frequency of a reference vibration) using an electronic device (detection device 1) that irradiates electromagnetic waves may include the following steps. That is, a vibration detection method according to one embodiment may include a step of setting the distance between the detection device 1 and the object 200 to be less than a predetermined value based on the diameter of an equiphase surface of the object 200 and the half-width of the gain of the antenna of the detection device 1. The vibration detection method may also include a step of detecting vibrations of the object 200 using the detection device 1 spaced a set distance from the object 200.

[0158] In one embodiment, the predetermined value may satisfy D=L / 2tan(α / 2), where D is the predetermined value, L is the diameter of the equiphase surface of the vibration of the object 200, and α is the half-width of the antenna gain of the detection device 1. Furthermore, when there are multiple equiphase surfaces of the object 200, the diameter of the smallest equiphase surface of the equiphase surfaces of the object 200 may be used as the diameter of the smallest equiphase surface.

[0159] In one embodiment, the object 200 may be vibrated by the vibration source 300. In this case, the vibration source 300 may continuously vibrate the object 200 at a constant frequency over time. In this case, the vibration source 300 may also vibrate the object 200 by acoustic vibration.

[0160] The vibration detection method according to one embodiment may include outputting a state about the object 200 based on the detected vibration.

[0161] (Other embodiments) Other embodiments will be described below.

[0162] In the above-described embodiment, the vibration source 300 has been described as applying acoustic vibration to the object 200. In this case, for example, the vibration source 300 may apply vibration in a contact manner using a piezoelectric speaker or an impulse hammer, or may apply vibration in a non-contact manner using a loud speaker via air. Also, in the above-described embodiment, the vibration source 300 has been described as applying vibration by contacting the object 200. However, in one embodiment, the vibration source 300 may apply vibration to the object 200 in a non-contact manner.

[0163] In the above-described embodiment, the detector 1 has been described as a millimeter-wave radar, for example. However, in one embodiment, the detector 1 may be a radar using any wavelength band other than the millimeter wave band, or may employ other sensors such as a piezoelectric sensor or an LDV. Furthermore, the detector 1 may employ, for example, a pulse radar or an FMCW radar as a radar system, or may employ any of various radar systems.

[0164] In the above-described embodiment, the vibration source 300 performs vibration at a single frequency, exciting only a specific vibration mode, and performing measurement using the detection device 1. However, in one embodiment, the vibration source 300 may excite multiple vibration modes at once, and performing measurement using the detection device 1. In this case, frequency filtering may be performed on the measured vibration waveform to extract only the vibration component due to the vibration mode corresponding to a single frequency, and the shape of the vibration mode may be determined.

[0165] In the above-described embodiment, measurements were performed using a single detector 1. However, in one embodiment, multiple detectors 1 may be used to simultaneously measure multiple measurement points. This can shorten the measurement time. In this case, the multiple detectors 1 may be synchronized in time by some means.

[0166] In the above-described embodiment, an example has been described in which the shape of a single vibration mode corresponding to a single frequency is acquired. However, in one embodiment, there may be multiple vibration modes to be measured. The vibration mode in which an abnormality is likely to occur may change depending on the degree of damage to the damaged portion 210 in the object 200. For this reason, the detection device 1 may perform measurements in as many vibration modes as possible. When performing measurements in multiple modes, the detection device 1 may change the conditions of the measurement point for each mode, or may use common conditions that allow the shape of the vibration mode with the shortest wavelength to be sufficiently grasped.

[0167] In the above-described embodiment, an example has been described in which the detection device 1 detects vibrations of the object 200 from only one direction. However, in one embodiment, the detection device 1 may measure vibrations of the object 200 from any direction. In one embodiment, the detection device 1 may acquire two-dimensional or three-dimensional shapes of each vibration mode.

[0168] In the above-described embodiment, it has been assumed that the detection device 1 continues to acquire data while moving between measurement points. When time synchronization between the excitation waveform and the measurement data is sequentially achieved, the detection device 1 and / or the electronic device 100 may associate the measurement data with the phase of the excitation waveform. In this case, the detection device 1 does not need to continue to acquire data while moving between measurement points. Also, in this case, in a system including the detection device 1 and / or the electronic device 100, the excitation source 300 and the signal generator 400 do not need to continue to vibrate the detection device 1 while it moves between measurement points.

[0169] In the above-described embodiment, the electronic device 100 displays the vibration mode using only one point corresponding to a phase of a certain excitation waveform at each measurement position, as shown in FIGS. 19A to 19D . However, in one embodiment, the electronic device 100 may extract several points instead of one point and perform denoising by averaging the extracted points. This allows the vibration mode to be displayed with higher accuracy. Furthermore, in one embodiment, the electronic device 100 may remove unnecessary frequency components from the measured vibration waveform by processing such as a frequency filter. This allows the vibration mode shape to be acquired with higher accuracy.

[0170] In this way, the electronic device 100 is configured to be able to detect vibrations of the object 200 that are excited at a predetermined frequency. The electronic device 100 acquires first measurement information by measuring the vibrations of the object 200 at a first time point when the excitation of the object 200 is at a first phase. The electronic device 100 also acquires second measurement information by measuring the vibrations of the object 200 at a second time point when the excitation of the object 200 is at a second phase that is the same as the first phase. The electronic device 100 then detects the vibrations of the object 200 based on the first measurement information and the second measurement information.

[0171] Furthermore, the electronic device 100 may measure the vibration of the object 200 based on the output from the detection device 1. Furthermore, the electronic device 100 may measure the vibration of the object 200 at a first time point different from the position of the object 200 at a second time point.

[0172] The object 200 may be vibrated by the vibration source 300. In this case, the vibration source 300 may continuously vibrate the object 200 at a constant vibration frequency over time. Alternatively, the vibration source 300 may vibrate the object 200 by acoustic vibration. In this case, the first phase and the second phase may be the phases of the acoustic vibration that vibrates the object 200.

[0173] Furthermore, the time difference t between the first point in time and the second point in time may be given by t=n / f, where f is a predetermined frequency at which the object 200 is vibrated and n is a natural number.

[0174] Furthermore, the electronic device 100 may perform time synchronization at two points P1 and P2 that are separated by an arbitrary time interval, thereby assuming that vibrations applied to the object 200 are in phase at P1 and P2. In this case, the electronic device 100 may perform a fast Fourier transform on the signal for a certain period after P2, multiply the result by a complex phase, and then perform an inverse fast Fourier transform. On the other hand, in the above case, the electronic device 100 may apply a Hilbert transform to the signal for a certain period after P2, convert it into an analytic signal containing amplitude and phase information at each point in time, and multiply the result by a complex phase.

[0175] In one embodiment, the operations and / or processes of the electronic device 100 as described above may be performed by the processor 102.

[0176] While the present disclosure has been described based on various drawings and examples, it should be noted that those skilled in the art would easily be able to make various modifications and alterations based on the present disclosure. Therefore, it should be noted that these modifications and alterations are within the scope of the present disclosure. For example, the functions contained in each functional unit can be rearranged so as not to cause logical inconsistencies. Multiple functional units may be combined into one or divided. The above-described embodiments of the present disclosure are not limited to faithful implementation of each of the described embodiments, but may be implemented by combining features or omitting some features as appropriate. In other words, those skilled in the art can make various modifications and alterations based on the present disclosure. Therefore, these modifications and alterations are within the scope of the present disclosure. For example, in each embodiment, each functional unit, means, step, etc. can be added to other embodiments so as not to cause logical inconsistencies, or can be replaced with each functional unit, means, step, etc. of other embodiments. Furthermore, in each embodiment, multiple functional units, means, steps, etc. can be combined into one or divided into two or more. Furthermore, each of the above-described embodiments of the present disclosure is not limited to being implemented faithfully according to each of the described embodiments, but can also be implemented by combining each feature or omitting some of them as appropriate.

[0177] The above-described embodiments are not limited to implementation as devices such as the electronic device 100. For example, the above-described embodiments may be implemented as a control method for devices such as the electronic device 100. Furthermore, the above-described embodiments may be implemented as a program executed by a device such as the electronic device 100, or as a storage medium or recording medium on which a program is recorded.

[0178] The detection device 1 according to the above-described embodiment has been described as including components constituting a so-called radar sensor, such as the transmitting antenna array 24 and the receiving antenna array 31. However, the electronic device according to the embodiment may be implemented as, for example, a configuration such as the signal processing unit 10. In this case, the signal processing unit 10 may be implemented as having a function of processing signals handled by the transmitting antenna array 24, the receiving antenna array 31, etc. [Explanation of symbols]

[0179] 1. Detection equipment 10 Signal Processing Section 11 Signal generation processing section 12 Received signal processing section 21 Transmit DAC 22 Transmitting circuit 23 Millimeter wave transmitter circuit 24 Transmitting Antenna Array 31 Receiving Antenna Array 32 Mixer 33 Receiving circuit 34 Receive ADC 100 Electronic equipment 102 processors 104 Display section 106 Storage section 108 Communications Department 110 Operation section 200 objects 300 Excitation source 400 Signal Generator

Claims

1. A method for detecting vibrations of an object vibrating at a predetermined frequency by an electronic device that irradiates electromagnetic waves, comprising: setting a distance between the electronic device and the object to be less than a predetermined value based on a diameter of an equiphase surface of the object and a half-width of a gain of an antenna of the electronic device; detecting vibrations of the object by the electronic device spaced apart from the object by the set distance; A vibration detection method comprising:

2. 2. The vibration detection method according to claim 1, wherein the predetermined value satisfies D<L / 2 tan(α / 2), where D is the predetermined value, L is a diameter of an equiphase surface of the vibration of the object, and α is a half-value width of an antenna gain of the electronic device.

3. 2. The vibration detection method according to claim 1, wherein the diameter of the equiphase surface of the object is the diameter of the smallest equiphase surface among the equiphase surfaces of the object.

4. The object is excited by an excitation source; The vibration detection method according to claim 1 , wherein the vibration source continuously vibrates the object at a constant frequency over time.

5. The vibration detection method according to claim 4 , wherein the vibration source vibrates the object with acoustic vibration.

6. The vibration detection method according to claim 1 , further comprising the step of outputting a state of the object based on the detected vibration.

Images