Diagnostic method, diagnostic device, and diagnostic system

Abstract

A diagnosis method, a diagnosis device, and a diagnosis system capable of suppressing deterioration of diagnosis accuracy caused by a deviation in a setting direction. The diagnosis method includes: a physical quantity detection step of detecting a physical quantity generated in a diagnosis target with a physical quantity sensor; a Lissajous figure generation step of generating a three-dimensional Lissajous figure by plotting the physical quantity detected in the physical quantity detection step in a three-dimensional coordinate system having a first axis, a second axis, and a third axis; a vibration surface information acquisition step of acquiring information related to a vibration surface of a vibration from the three-dimensional Lissajous figure generated in the Lissajous figure generation step; and a diagnosis step of diagnosing a state of the diagnosis target based on the information related to the vibration surface acquired in the vibration surface information acquisition step.

Description

Technical Field

[0001] This invention relates to diagnostic methods, diagnostic devices, and diagnostic systems. Background Technology

[0002] The anomaly diagnosis device described in Patent Document 1 comprises: a vibration detection device that detects vibrations at predetermined positions on two axes and outputs vibration waveform signals; a Lissajous waveform generation device that generates a Lissajous waveform based on the two vibration waveform signals output by the vibration detection device; a reference Lissajous waveform setting device that pre-sets and stores multiple reference Lissajous waveforms imagined based on the causes of each anomaly; and an anomaly cause determination device that compares the Lissajous waveform generated by the Lissajous waveform generation device with the reference Lissajous waveforms stored in the reference Lissajous waveform setting device, determines the cause of the anomaly, and outputs the result.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2000-258305

[0004] However, in such an anomaly diagnosis device as Patent Document 1, since a reference Lissajous waveform diagram corresponding to the setting direction of the sensor for the object to which the device is applied is prepared in advance, there is a risk that the diagnostic accuracy will deteriorate due to deviation of the setting direction. Summary of the Invention

[0005] The diagnostic method of the present invention includes: a physical quantity detection step, wherein a physical quantity sensor is used to detect a physical quantity generated in the object being diagnosed;

[0006] The Lissajous figure generation step generates a three-dimensional Lissajous figure by depicting the physical quantity detected in the physical quantity detection step in a three-dimensional coordinate system having a first axis, a second axis, and a third axis.

[0007] The vibration surface information acquisition step involves obtaining information related to the vibration surface from the three-dimensional Lissajous figure generated in the Lissajous figure generation step; and

[0008] The diagnostic step involves diagnosing the state of the object under diagnosis based on the information related to the vibration surface obtained in the vibration surface information acquisition step.

[0009] The diagnostic device of the present invention performs the following steps: a physical quantity detection step, in which a physical quantity sensor is used to detect the physical quantity generated in the diagnostic object;

[0010] The Lissajous figure generation step generates a three-dimensional Lissajous figure by depicting the physical quantity detected in the physical quantity detection step in a three-dimensional coordinate system having a first axis, a second axis, and a third axis.

[0011] The vibration surface information acquisition step involves acquiring information related to the vibration surface from the three-dimensional Lissajous figure generated in the Lissajous figure generation step.

[0012] The diagnostic step involves diagnosing the state of the object under diagnosis based on the information related to the vibration surface obtained in the vibration surface information acquisition step.

[0013] The diagnostic system of the present invention comprises: a physical quantity sensor for detecting a physical quantity generated in the object being diagnosed; and

[0014] The diagnostic device diagnoses the state of the object being diagnosed based on the detection signals from the physical quantity sensor.

[0015] The diagnostic device performs the following steps:

[0016] The physical quantity detection step involves using a physical quantity sensor to detect the physical quantities generated by the object being diagnosed.

[0017] The Lissajous figure generation step generates a three-dimensional Lissajous figure by depicting the physical quantities detected in the physical quantity detection step in a three-dimensional coordinate system of the first axis, the second axis, and the third axis.

[0018] The vibration surface information acquisition step involves obtaining information related to the vibration surface from the three-dimensional Lissajous figure generated in the Lissajous figure generation step; and

[0019] The diagnostic step involves diagnosing the state of the object under diagnosis based on the information related to the vibration surface obtained in the vibration surface information acquisition step. Attached Figure Description

[0020] Figure 1 This is a diagram showing the overall structure of the diagnostic system according to the first embodiment.

[0021] Figure 2 This is a cross-sectional view of a vacuum pump.

[0022] Figure 3 This is a block diagram of the sensor unit.

[0023] Figure 4 This is a flowchart illustrating the diagnostic process of a diagnostic system.

[0024] Figure 5 This is a diagram illustrating digital timing signals.

[0025] Figure 6 It is a diagram showing a three-dimensional Lissajous figure.

[0026] Figure 7 This is a diagram showing a two-dimensional Lissajous figure as viewed from the X-axis direction.

[0027] Figure 8 This is a diagram showing a two-dimensional Lissajous figure as viewed from the X' axis direction.

[0028] Figure 9 This is a diagram showing the rotation angle Ψ1.

[0029] Figure 10 This is a diagram showing a two-dimensional Lissajous figure as viewed from the Z-axis direction.

[0030] Figure 11 This is a diagram showing a two-dimensional Lissajous figure as viewed from the Z' axis.

[0031] Figure 12 This is a diagram showing the rotation angle Ψ2.

[0032] Figure 13 It is a graph showing the change of rotation angle Ψ1 over time.

[0033] Figure 14 It is a graph showing the change of rotation angle Ψ2 over time.

[0034] Figure 15 It is a graph showing the time-dependent changes in the standard deviations of rotation angles Ψ1 and Ψ2.

[0035] Figure 16 It is a graph showing the time-dependent changes in the standard deviations of rotation angles Ψ1 and Ψ2.

[0036] Figure 17 This is a diagram illustrating a three-dimensional Lissajous figure according to the second embodiment.

[0037] Figure 18 This is a diagram illustrating a two-dimensional Lissajous figure according to the third embodiment.

[0038] Explanation of reference numerals in the attached figures

[0039] 1…Diagnostic system, 2…Sensor unit, 21x…Acceleration sensor, 21y…Acceleration sensor, 21z…Acceleration sensor, 22x…Processing circuit, 22y…Processing circuit, 22z…Processing circuit, 3…Diagnostic device, 4…Display device, 9…Diagnostic object, 90…Vacuum pump, 91…Housing, 92…Pump chamber, 921…Inlet, 922…Exhaust port, 931…Pump rotor, 932…Pump rotor, 941…Motor, 942…Electric… Machine, A…Predetermined direction, Ax…Acceleration, Ay…Acceleration, Az…Acceleration, DAx…Digital timing signal, DAy…Digital timing signal, DAz…Digital timing signal, F…Vibration surface, L…Plotting point, LF…Three-dimensional Lissajous figure, S1…Physical quantity detection step, S2…Lissajous figure generation step, S3…Vibration surface information acquisition step, S4…Diagnostic step, T1…Time, V…Rotation vector, Ψ1…Rotation angle, Ψ2…Rotation angle. Detailed Implementation

[0040] Hereinafter, preferred embodiments of the diagnostic method, diagnostic apparatus, and diagnostic system of the present invention will be described in detail.

[0041] First Implementation Method

[0042] Figure 1 This is a diagram showing the overall structure of the diagnostic system according to the first embodiment. Figure 2 This is a cross-sectional view of a vacuum pump. Figure 3 This is a block diagram of the sensor unit. Figure 4 This is a flowchart illustrating the diagnostic process of a diagnostic system. Figure 5 This is a diagram illustrating digital timing signals. Figure 6 It is a diagram showing a three-dimensional Lissajous figure. Figure 7 This is a diagram showing a two-dimensional Lissajous figure as viewed from the X-axis direction. Figure 8 This is a diagram showing a two-dimensional Lissajous figure as viewed from the X' axis direction. Figure 9 This is a diagram showing the rotation angle Ψ1. Figure 10 This is a diagram showing a two-dimensional Lissajous figure as viewed from the Z-axis direction. Figure 11 This is a diagram showing a two-dimensional Lissajous figure as viewed from the Z' axis. Figure 12 This is a diagram showing the rotation angle Ψ2. Figure 13 It is a graph showing the change of rotation angle Ψ1 over time. Figure 14 It is a graph showing the change of rotation angle Ψ2 over time. Figure 15 as well as Figure 16 These are graphs showing the changes in the standard deviations of rotation angles Ψ1 and Ψ2 over time. It should be noted that, for ease of explanation, the three orthogonal axes are designated as the X-axis, Y-axis, and Z-axis.

[0043] Figure 1 The diagnostic system 1 shown is a system for analyzing the vibration of the diagnostic object 9 and diagnosing the state of the diagnostic object 9. It includes a sensor unit 2 for detecting the vibration of the diagnostic object 9, a diagnostic device 3 for diagnosing the state of the diagnostic object 9 based on the detection signal of the sensor unit 2, and a display device 4 for reporting the required information to the user.

[0044] It should be noted that the diagnostic object 9 is not particularly limited. For example, it can be various devices such as motors with rotating or vibrating mechanisms, structures such as bridges and buildings that vibrate due to external forces, or electrical circuits that generate periodic signals.

[0045] In this embodiment, the diagnostic object 9 is the vacuum pump 90. For example... Figure 1 as well as Figure 2 As shown, the vacuum pump 90 includes: a housing 91; a pump chamber 92 formed within the housing 91 and having an intake port 921 and an exhaust port 922; a pair of pump rotors 931 and 932 disposed within the pump chamber 92; and a pair of motors 941 and 942 that rotate the pump rotors 931 and 932 around their central axis. Thus, the motors 941 and 942 rotate the pump rotors 931 and 932 in opposite directions, thereby drawing air from the intake port 921 and discharging air from the exhaust port 922. In this vacuum pump 90 structure, vibration is generated due to the rotation of the pump rotors 931 and 932.

[0046] In diagnostic system 1, the vibration of vacuum pump 90 is detected, the detected vibration is analyzed, and the condition of vacuum pump 90 is diagnosed. For example... Figure 1 As shown, sensor unit 2 is mounted on the housing 91 of vacuum pump 90 to detect physical quantities generated by the vibration of vacuum pump 90. The mounting location of sensor unit 2 is not particularly limited as long as it can detect the physical quantities generated by the vibration of vacuum pump 90. Furthermore, sensor unit 2 can be installed or removed during each diagnostic test, or it can be permanently installed.

[0047] Furthermore, no particular limitation is made on the physical quantities generated by the vibration of the vacuum pump 90; for example, acceleration, angular velocity, velocity, displacement, pressure, current, voltage, etc., can be listed. The following explanation will focus on the case where acceleration is the physical quantity generated by the vibration of the vacuum pump 90.

[0048] like Figure 3 As shown, the sensor unit 2 has three acceleration sensors 21x, 21y, and 21z that serve as physical quantity sensors, and three processing circuits 22x, 22y, and 22z that process the signals from the acceleration sensors 21x, 21y, and 21z.

[0049] In addition, accelerometer 21x detects acceleration Ax in the X-axis direction, accelerometer 21y detects acceleration Ay in the Y-axis direction, and accelerometer 21z detects acceleration Az in the Z-axis direction. These three accelerometers 21x, 21y, and 21z are synchronized with each other and periodically detect accelerations Ax, Ay, and Az at the same timing interval.

[0050] It should be noted that, for example, the accelerometers 21x, 21y, and 21z can be sensors using MEMS (Micro ElectroMechanical Systems) oscillators or sensors using crystal oscillators. Furthermore, for example, the accelerometers 21x, 21y, and 21z can be integrated into a device such as an IMU (Inertial Measurement Unit), or at least one of the accelerometers 21x, 21y, and 21z can be physically separated from other sensors.

[0051] In addition, the processing circuit 22x processes the detection signal from the accelerometer 21x and outputs the digital timing signal DAx of the acceleration Ax, the processing circuit 22y processes the detection signal from the accelerometer 21y and outputs the digital timing signal DAy of the acceleration Ay, and the processing circuit 22z processes the detection signal from the accelerometer 21z and outputs the digital timing signal DAz of the acceleration Az.

[0052] The diagnostic device 3 processes the three digital timing signals DAx, DAy, and DAz output from the sensor unit 2 and diagnoses the state of the vacuum pump 90. For example, the diagnostic device 3 includes a processor configured as a computer to process information, a memory connected to the processor in a communicative manner, and an external interface for connecting to external devices. The memory stores various programs that can be executed by the processor, and the processor can read and execute these programs stored in the memory.

[0053] like Figure 4 As shown, the diagnostic system 1 performs the following steps: physical quantity detection step S1, using sensor unit 2 to detect physical quantities generated due to the vibration of vacuum pump 90; Lissajous figure generation step S2, generating a three-dimensional Lissajous figure LF based on the detection results in physical quantity detection step S1; vibration surface information acquisition step S3, acquiring information related to the vibration surface F generated by the vibration of vacuum pump 90 from the three-dimensional Lissajous figure LF generated in Lissajous figure generation step S2; and diagnostic step S4, diagnosing the state of vacuum pump 90 based on the information related to vibration surface F acquired in vibration surface information acquisition step S3.

[0054] Physical quantity detection step S1

[0055] In the physical quantity detection step S1, such as Figure 5 As shown, the diagnostic device 3 acquires three digital timing signals DAx, DAy, and DAz output from the sensor unit 2.

[0056] Lissajous figure generation step S2

[0057] In the Lissajous figure generation step S2, the diagnostic device 3, based on the data obtained in the physical quantity detection step S1... Figure 5 The digital timing signals DAx, DAy, and DAz shown are as follows: Figure 6 As shown, a three-dimensional Lissajous figure LF is generated in a three-dimensional orthogonal coordinate system consisting of the X-axis, Y-axis, and Z-axis. That is, the diagnostic device 3 assigns a digital timing signal DAx to the X-axis, a digital timing signal DAy to the Y-axis, and a digital timing signal DAz to the Z-axis, thereby generating the three-dimensional Lissajous figure LF in the three-dimensional orthogonal coordinate system. It should be noted that in this embodiment, the X-axis is the first axis, the Y-axis is the second axis, and the Z-axis is the third axis.

[0058] Step S3 for obtaining vibration surface information

[0059] Here, the inventors focused their research and discovered that there are many cases where three-dimensional Lissajous figures (LF) vibrate on a predetermined plane. Therefore, as... Figure 6 As shown, in the vibration surface information acquisition step S3, the diagnostic device 3 determines the "predetermined plane" as the vibration surface F based on the three-dimensional Lissajous figure LF generated in the Lissajous figure generation step S2, and acquires the determined information related to the vibration surface F. The method for determining the vibration surface F is not particularly limited; for example, the following methods can be listed.

[0060] First, such as Figure 7 As shown, the diagnostic device 3 views the three-dimensional Lissajous figure LF from the X-axis direction, projects each depicted point L of the three-dimensional Lissajous figure LF onto the YZ plane with the X-axis as the normal, and approximates the linear shape of each depicted point L using the least squares method. Hereinafter, this process is referred to as the first linear approximation process. Then, the diagnostic device 3 performs this first linear approximation process multiple times while changing the direction of viewing the three-dimensional Lissajous figure LF from the X-axis, wherein, as... Figure 8 As shown, the result that minimizes the error of the straight line approximation is determined. Next, as... Figure 9 As shown, the diagnostic device 3 sets the top view direction of the determined result as the X' axis direction, and determines the rotation angle Ψ1 of the X' axis relative to the X axis around the Y axis.

[0061] Next, as Figure 10As shown, the diagnostic device 3 views the three-dimensional Lissajous figure LF from the Z-axis direction, projects each depicted point L of the three-dimensional Lissajous figure LF onto the XY plane with the Z-axis as the normal, and approximates the linear shape of each depicted point L using the least squares method. Hereinafter, this process is referred to as the second linear approximation process. Then, the diagnostic device 3 performs this second linear approximation process multiple times while changing the direction of viewing the three-dimensional Lissajous figure LF from the Z-axis direction, wherein, as... Figure 11 As shown, the result that minimizes the error of the straight line approximation is determined. Next, as... Figure 12 As shown, the diagnostic device 3 sets the top view direction of the determined result as the Z' axis direction and determines the rotation angle Ψ2 of the Z' axis around the X axis relative to the Z axis.

[0062] Next, the diagnostic device 3 determines the vibration surface F based on the determined rotation angles Ψ1 and Ψ2. In this case, the surface defined by the X' axis and Z' axis becomes the vibration surface F. This method allows for easy determination of the vibration surface F. It should be noted that the more times the first linear approximation process is performed (i.e., the smaller the change around the Y-axis), the more accurately the rotation angle Ψ1 can be calculated; similarly, the more times the second linear approximation process is performed (i.e., the smaller the change around the X-axis), the more accurately the rotation angle Ψ2 can be calculated, thus improving the characteristic accuracy of the vibration surface F.

[0063] As described above, the diagnostic device 3 stores the determined information related to the vibration surface F. The diagnostic device 3 includes the following information as related to the vibration surface F: rotation angle Ψ1, rotation angle Ψ2, the top view of the three-dimensional Lissajous figure LF when viewed from the X' axis direction, the top view of the three-dimensional Lissajous figure LF when viewed from the Z' axis direction, and the top view of the three-dimensional Lissajous figure LF when viewed from the normal direction of the vibration surface F.

[0064] The diagnostic device 3 continuously or periodically performs the physical quantity detection step S1, the Lissajous figure generation step S2, and the vibration surface information acquisition step S3, accumulating at least two pieces of information related to the vibration surface F.

[0065] Diagnostic step S4

[0066] Next, the diagnostic device 3 diagnoses the state of the vacuum pump 90 based on the accumulated information related to the vibration surface F. The diagnostic device 3 performs diagnoses based on changes in the tilt of the vibration surface F and changes in the top-view shape of the three-dimensional Lissajous figure LF.

[0067] In the diagnosis based on the change in tilt of the vibration surface F, the diagnostic device 3 diagnoses the state of the vacuum pump 90 based on the change in rotation angle Ψ1 over time. Additionally, the diagnostic device 3 diagnoses the state of the vacuum pump 90 based on the change in rotation angle Ψ2 over time. The diagnostic method based on the change in tilt of the vibration surface F is not particularly limited.

[0068] The diagnostic method based on the change of rotation angle Ψ1 over time is not particularly limited. For example, it can diagnose an abnormality in vacuum pump 90 when rotation angle Ψ1 changes drastically. Alternatively, even without a drastic change in rotation angle Ψ1, if the difference between the minimum and maximum values ​​of rotation angle Ψ1 due to accumulated operating time exceeds a predetermined value, it can be diagnosed that vacuum pump 90 has reached the end of its lifespan. Based on this diagnostic method, the condition of vacuum pump 90 can be easily and appropriately diagnosed.

[0069] The diagnostic method based on the change of rotation angle Ψ2 over time is not particularly limited. For example, it can diagnose an abnormality in vacuum pump 90 when rotation angle Ψ2 changes drastically. Alternatively, even without a drastic change in rotation angle Ψ2, if the difference between the minimum and maximum values ​​of rotation angle Ψ2 due to accumulated operating time exceeds a predetermined value, it can be diagnosed that vacuum pump 90 has reached the end of its lifespan. Using this diagnostic method, the condition of vacuum pump 90 can be easily and appropriately diagnosed.

[0070] Furthermore, in the diagnosis based on the shape change of the three-dimensional Lissajous figure LF, the diagnostic device 3 diagnoses the state of the vacuum pump 90 based on the change in the top-view shape of the three-dimensional Lissajous figure LF viewed from the X' axis direction over time. Additionally, the diagnostic device 3 diagnoses the state of the vacuum pump 90 based on the change in the top-view shape of the three-dimensional Lissajous figure LF viewed from the Z' axis direction over time. Furthermore, the diagnostic device 3 diagnoses the state of the vacuum pump 90 based on the change in the top-view shape of the three-dimensional Lissajous figure LF viewed from the in-plane direction of the vibration surface F over time. Additionally, the diagnostic device 3 diagnoses the state of the vacuum pump 90 based on the change in the top-view shape of the three-dimensional Lissajous figure LF viewed from the normal direction of the vibration surface F over time. The diagnostic method based on the shape change of the three-dimensional Lissajous figure LF is not particularly limited.

[0071] The diagnostic method based on the change in the top-view shape of the three-dimensional Lissajous figure LF viewed from the X' axis over time is not particularly limited. For example, it is possible to diagnose an abnormality in the vacuum pump 90 when the top-view shape of the three-dimensional Lissajous figure LF changes drastically. Alternatively, even without a drastic change in the top-view shape, if the cumulative operating time has resulted in a difference of more than a fixed value between the top-view shape at the start of the initial diagnosis and the current top-view shape, it can be diagnosed that the vacuum pump 90 has reached the end of its lifespan. Based on this diagnostic method, the condition of the vacuum pump 90 can be easily and appropriately diagnosed.

[0072] The diagnostic method based on the change in the top view shape of the three-dimensional Lissajous figure LF viewed from the Z' axis over time is not particularly limited. For example, it is possible to diagnose an abnormality in the vacuum pump 90 when the top view shape of the three-dimensional Lissajous figure LF changes drastically. Alternatively, even without a drastic change in the top view shape, if the cumulative operating time has resulted in a difference of more than a fixed value between the top view shape at the start of the diagnosis and the current top view shape, it is possible to diagnose that the vacuum pump 90 has reached the end of its lifespan. Based on this diagnostic method, the condition of the vacuum pump 90 can be easily and appropriately diagnosed.

[0073] The diagnostic method based on the change in the top-view shape of the three-dimensional Lissajous figure LF viewed from the in-plane direction of the vibration surface F over time is not particularly limited. For example, it is possible to diagnose an abnormality in the vacuum pump 90 when the top-view shape of the three-dimensional Lissajous figure LF changes drastically. Alternatively, even without a drastic change in the top-view shape, if the cumulative operating time has resulted in a difference of more than a fixed value between the top-view shape at the start of the diagnosis and the current top-view shape, it is possible to diagnose that the vacuum pump 90 has reached the end of its lifespan. Based on this diagnostic method, the condition of the vacuum pump 90 can be easily and appropriately diagnosed.

[0074] The diagnostic method based on the change in the top-view shape of the three-dimensional Lissajous figure LF viewed from the normal direction of the vibration surface F over time is not particularly limited. For example, it is possible to diagnose an abnormality in the vacuum pump 90 when the top-view shape of the three-dimensional Lissajous figure LF changes drastically. Alternatively, even without a drastic change in the top-view shape, if the cumulative operating time has resulted in a difference of more than a fixed value between the top-view shape at the start of the diagnosis and the current top-view shape, it is possible to diagnose that the vacuum pump 90 has reached the end of its lifespan. Based on this diagnostic method, the condition of the vacuum pump 90 can be easily and appropriately diagnosed.

[0075] Among these, the example of the time-dependent changes in rotation angles Ψ1 and Ψ2 will be used as a representative illustration. Figure 13 The diagram shows the time-dependent change in the rotation angle Ψ1. Figure 14The diagram shows the time-dependent change in the rotation angle Ψ2. For example, in... Figure 13 as well as Figure 14 At time T1, as shown, both rotation angles Ψ1 and Ψ2 change abruptly. Therefore, the diagnostic device 3 can diagnose an abnormality in the vacuum pump 90 at time T1.

[0076] in addition, Figure 15 as well as Figure 16 The diagram shows the time-dependent changes in the standard deviations of rotation angles Ψ1 and Ψ2. It should be noted that... Figure 15 as well as Figure 16 The result is from the same model of vacuum pump (90), but... Figure 16 Compare Figure 15 The total working time is longer. For example, Figure 15 as well as Figure 16 As shown, the longer the vacuum pump 90 operates, the larger the standard deviations of the rotation angles Ψ1 and Ψ2 become, and the more unstable the orientation of the vibration surface F becomes. Furthermore, it can be seen that the rate of change of the standard deviation increases with the total operating time. Based on this information, the diagnostic device 3 can diagnose the lifespan and maintenance schedule of the vacuum pump 90.

[0077] By using the above indicators for diagnosis, the rotation angles Ψ1 and Ψ2 absorb the orientation error of the detection axes of the accelerometers 21x, 21y, and 21z caused by the deviation in the setting direction of the sensor unit 2. For the top view of the three-dimensional Lisajous figure LF (hereinafter also referred to as the "two-dimensional Lisajous figure"), the error no longer has an impact. That is to say, by calculating the two-dimensional Lisajous figure that excludes the dependence on the setting direction, a diagnostic system 1 with superior diagnostic accuracy is achieved. Furthermore, when the sensor unit 2 is placed on the vacuum pump 90, i.e., when the setting direction of the sensor unit 2 does not change, the phase information, amplitude ratio, and ratio of higher harmonic components between the digital timing signals DAx, DAy, and DAz will affect the rotation angles Ψ1 and Ψ2, thus enabling further diverse diagnoses based on changes in the rotation angles Ψ1 and Ψ2. In particular, the phase information is dimensionless, thus offering the advantage of being applicable regardless of the characteristics or setting of the sensor unit 2.

[0078] Furthermore, based on the diagnostic method described above, the vibration of the vacuum pump 90 can be separated into rotation angles Ψ1 and Ψ2 and a two-dimensional Lissajous figure. Therefore, diagnosis can be performed from different perspectives, namely, the shifts in rotation angles Ψ1 and Ψ2 and the image recognition of the two-dimensional Lissajous figure, thus enabling a more detailed diagnosis of the vacuum pump 90.

[0079] The above describes the diagnostic system 1. As previously described, the diagnostic method performed by such a diagnostic system 1 includes: a physical quantity detection step S1, in which accelerometers 21x, 21y, and 21z, acting as physical quantity sensors, detect physical quantities generated in the diagnostic object 9; a Lissajous figure generation step S2, in which a three-dimensional Lissajous figure LF is generated by depicting the physical quantities detected in the physical quantity detection step S1 in a three-dimensional coordinate system having a first axis, a second axis, and a third axis; a vibration surface information acquisition step S3, in which information related to the vibration surface F of the vibration is acquired from the three-dimensional Lissajous figure LF generated in the Lissajous figure generation step S2; and a diagnostic step S4, in which the state of the diagnostic object 9 is diagnosed based on the information related to the vibration surface F acquired in the vibration surface information acquisition step S3. According to this diagnostic method, as information related to the vibration surface F, information unaffected by the deviation of the detection axes of the accelerometers 21x, 21y, and 21z can be acquired, for example, a two-dimensional Lissajous figure. Therefore, it is possible to suppress the decrease in diagnostic accuracy caused by the deviation of the detection axes of the accelerometers 21x, 21y, and 21z.

[0080] Furthermore, as mentioned earlier, in diagnostic step S4, the state of the diagnostic object 9 is diagnosed based on the change in the shape of the three-dimensional Lissajous figure LF, i.e., the two-dimensional Lissajous figure, observed from the in-plane direction of the vibration surface F, over time. According to this diagnostic method, the state of the vacuum pump 90 can be easily and appropriately diagnosed.

[0081] Furthermore, as mentioned earlier, in diagnostic step S4, the state of the diagnostic object 9 is diagnosed based on the change in the shape of the three-dimensional Lissajous figure LF, i.e., the two-dimensional Lissajous figure, observed from the normal direction of the vibration surface F, over time. According to this diagnostic method, the state of the vacuum pump 90 can be easily and appropriately diagnosed.

[0082] Furthermore, as mentioned earlier, in diagnostic step S4, the state of the diagnostic object 9 is diagnosed based on the change in the tilt of the vibrating surface F over time. Using this diagnostic method, the state of the vacuum pump 90 can be easily and appropriately diagnosed.

[0083] Furthermore, as mentioned earlier, in step S3 of obtaining vibration surface information, among multiple planes that face different directions, the plane with the smallest error obtained by approximating each depicted point L of the three-dimensional Lissajous figure LF projected onto the plane using the least squares method is taken as the vibration surface F. This method allows for easy determination of the vibration surface F.

[0084] Furthermore, as described above, the diagnostic device 3 of the diagnostic system 1 performs the following steps: a physical quantity detection step S1, using accelerometers 21x, 21y, and 21z as physical quantity sensors to detect physical quantities generated in the diagnostic object 9; a Lissajous figure generation step S2, generating a three-dimensional Lissajous figure LF by depicting the physical quantities detected in the physical quantity detection step S1 in a three-dimensional coordinate system having a first axis, a second axis, and a third axis; a vibration surface information acquisition step S3, acquiring information related to the vibration surface F from the three-dimensional Lissajous figure LF generated in the Lissajous figure generation step S2; and a diagnostic step S4, diagnosing the state of the diagnostic object 9 based on the information related to the vibration surface F acquired in the vibration surface information acquisition step S3. According to this diagnostic device 3, information related to the vibration surface F, unaffected by deviations in the detection axes of the accelerometers 21x, 21y, and 21z, such as a two-dimensional Lissajous figure, can be acquired. Therefore, it is possible to suppress the decrease in diagnostic accuracy caused by the deviation of the detection axes of the accelerometers 21x, 21y, and 21z.

[0085] Furthermore, as described above, the diagnostic system 1 includes accelerometers 21x, 21y, and 21z, which are physical quantity sensors for detecting physical quantities generated in the diagnostic object 9; and a diagnostic device 3 for diagnosing the state of the diagnostic object 9 based on the detection signals of the accelerometers 21x, 21y, and 21z. The diagnostic device 3 performs the following steps: a physical quantity detection step S1, using the accelerometers 21x, 21y, and 21z as physical quantity sensors to detect physical quantities generated in the diagnostic object 9; a Lissajous figure generation step S2, generating a three-dimensional Lissajous figure LF by depicting the physical quantities detected in the physical quantity detection step S1 on a three-dimensional coordinate system having a first axis, a second axis, and a third axis; a vibration surface information acquisition step S3, acquiring information related to the vibration surface F of vibration from the three-dimensional Lissajous figure LF generated in the Lissajous figure generation step S2; and a diagnostic step S4, diagnosing the state of the diagnostic object 9 based on the information related to the vibration surface F acquired in the vibration surface information acquisition step S3. According to such a diagnostic system 1, as information related to the vibration surface F, it is possible to obtain information unaffected by the deviations of the detection axes of the accelerometers 21x, 21y, and 21z, such as a two-dimensional Lissajous figure. Therefore, it is possible to suppress the reduction in diagnostic accuracy caused by the deviations of the detection axes of the accelerometers 21x, 21y, and 21z.

[0086] Second Implementation Method

[0087] Figure 17 This is a diagram illustrating a three-dimensional Lissajous figure according to the second embodiment.

[0088] The diagnostic system 1 of this embodiment is the same as the diagnostic system 1 of the first embodiment described above, except for the method of acquiring information related to the vibration surface F. Therefore, in the following description, this embodiment will be described mainly for its differences from the first embodiment described above, and descriptions of the same matters will be omitted. In addition, in the drawings of this embodiment, the same reference numerals are used for the same structures as in the embodiments described above.

[0089] In the vibration surface information acquisition step S3, the diagnostic device 3 determines the vibration surface F and acquires information related to the vibration surface F in the following manner. It should be noted that, for ease of explanation, the number of depiction points L included in the three-dimensional Lisajous figure LF is set to n (where n is an integer greater than 2), and they are arranged in chronological order (from oldest to newest) as depiction points L1, L2, L3, ..., L... n .

[0090] First, the diagnostic device 3 calculates the distance from the drawing point L1 to the drawing point L. n+1 The angular velocity vectors at each plotted point L. The method for obtaining the angular velocity vectors is based on the i-th plotted point L (where i is an integer greater than or equal to 1 and less than or equal to n-1). i coordinates (x) i y i , z i ) and the (i+1)th drawing point L i+1 coordinates (x) i+1 y i+1 , z i+1 Find Δ = L i+1 -L i Furthermore, by calculating L i ×Δ can be used to obtain the i-th plotting point L. i The angular velocity vector at that point. It should be noted that "×" in the formula represents the cross product.

[0091] Next, the diagnostic device 3 calculates the distance from the depiction point L1 to the depiction point L. n+1 The sum of the angular velocity vectors at each depicted point L is used to set the obtained vector as the rotation vector V of the three-dimensional Lissajous figure LF. Then, as... Figure 17 As shown, the diagnostic device 3 defines the surface orthogonal to the rotation vector V as the vibration surface F. Furthermore, the diagnostic device 3 determines the rotation angle Ψ1 of the rotation vector relative to the X-axis around the Y-axis, and the rotation angle Ψ2 of the rotation vector relative to the Z-axis around the X-axis. Using this method, the vibration surface F can be easily determined.

[0092] In diagnostic step S4, diagnostic device 3 diagnoses the state of vacuum pump 90 based on accumulated information related to the vibration surface F. The diagnostic method is the same as in the first embodiment described above, performing diagnoses based on changes in the tilt of the vibration surface F and changes in the top-view shape of the three-dimensional Lissajous figure LF. In the diagnosis based on changes in the tilt of the vibration surface F, diagnostic device 3 diagnoses the state of vacuum pump 90 based on changes in rotation angles Ψ1 and Ψ2 over time. Similarly, in the diagnosis based on changes in the shape of the three-dimensional Lissajous figure LF, diagnostic device 3 diagnoses the state of vacuum pump 90 based on changes in the top-view shape of the three-dimensional Lissajous figure LF viewed along the direction of the rotation vector over time. The diagnostic method is not particularly limited.

[0093] As described above, in the diagnostic method of this embodiment, the surface orthogonal to the vector obtained by summing the vectors at each depicted point L of the three-dimensional Lissajous figure LF per unit time is defined as the vibration surface F. With this method, the vibration surface F can be easily determined.

[0094] According to this second embodiment, the same effect as the first embodiment described above can be achieved.

[0095] Third Implementation Method

[0096] Figure 18 This is a diagram illustrating a two-dimensional Lissajous figure according to the third embodiment.

[0097] The diagnostic system 1 of this embodiment is the same as the diagnostic system 1 of the first embodiment described above, except that the method for acquiring information related to the vibration surface F is different. Therefore, in the following description, this embodiment will be described mainly in terms of its differences from the first embodiment described above, and descriptions of the same matters will be omitted. In addition, in the figures of this embodiment, the same reference numerals are used to mark the same structures as in the embodiments described above.

[0098] In the vibration surface information acquisition step S3, the diagnostic device 3 determines the vibration surface F and acquires information related to the vibration surface F in the following manner. It should be noted that, for ease of explanation, the number of depiction points L included in the three-dimensional Lisajous figure LF is set to n (where n is an integer greater than or equal to 2), and they are arranged in chronological order (from oldest to newest) as depiction points L1, L2, L3, ..., L... n .

[0099] First, such as Figure 18 As shown, the diagnostic device 3 views the three-dimensional Lissajous figure LF from a predetermined direction A and projects the three-dimensional Lissajous figure LF onto a plane orthogonal to the predetermined direction A. Figure 18In this context, a predetermined direction A is fixed as the Z-axis direction. Next, the diagnostic device 3 calculates the area of ​​the three-dimensional Lisajous figure. For example, the area of ​​the three-dimensional Lisajous figure can be calculated as follows. First, the diagnostic device 3 calculates the origin of the three-dimensional orthogonal coordinate system and the i-th drawing point L for all i (where i is an integer greater than or equal to 1 and less than or equal to n-1). i and the (i+1)th drawing point L i+1 The area of ​​the connected triangles. Next, the diagnostic device 3 sums up the areas of all the n-1 triangles and uses it as the area of ​​the three-dimensional Lissajous figure LF (hereinafter, this process is also referred to as the "area calculation process").

[0100] Then, the diagnostic device 3 performs the area calculation process multiple times while changing the predetermined direction A to the X-axis, Y-axis, and Z-axis, determining the result that maximizes the area of ​​the three-dimensional Lisajous figure LF. Next, the diagnostic device 3 defines the plane orthogonal to the predetermined direction A of the determined result as the vibration surface F. Furthermore, it determines the rotation angle Ψ1 of the predetermined direction A relative to the X-axis around the Y-axis, and the rotation angle Ψ2 of the predetermined direction A relative to the Z-axis around the X-axis. Using this method, the vibration surface F can be easily determined.

[0101] In diagnostic step S4, the diagnostic device 3 diagnoses the state of the vacuum pump 90 based on accumulated information related to the vibration surface F. The diagnostic method is the same as in the first embodiment described above, performing diagnoses based on changes in the tilt of the vibration surface F and changes in the top-view shape of the three-dimensional Lissajous figure LF. In the diagnosis based on changes in the tilt of the vibration surface F, the diagnostic device 3 diagnoses the state of the vacuum pump 90 based on changes in rotation angles Ψ1 and Ψ2 over time. Similarly, in the diagnosis based on changes in the shape of the three-dimensional Lissajous figure LF, the diagnostic device 3 diagnoses the state of the vacuum pump 90 based on changes in the top-view shape of the three-dimensional Lissajous figure LF viewed from the direction along the rotation vector over time. The diagnostic method is not particularly limited.

[0102] As described above, in the diagnostic method of this embodiment, among multiple planes that face different directions, the plane with the largest area of ​​the three-dimensional Lissajous figure LF projected onto the plane is taken as the vibration surface F. This method allows for easy determination of the vibration surface F.

[0103] This third implementation method can achieve the same effect as the first implementation method described above.

[0104] The diagnostic method, diagnostic apparatus, and diagnostic system of the present invention have been described above based on the illustrated embodiments. However, the present invention is not limited thereto, and the structure of each part can be replaced with any structure having the same function. In addition, the present invention may also include other arbitrary structures.

Claims

1. A diagnostic method, characterized in that, include: The physical quantity detection step involves using a physical quantity sensor to detect the physical quantities generated by the object being diagnosed. The Lissajous figure generation step generates a three-dimensional Lissajous figure by depicting the physical quantity detected in the physical quantity detection step in a three-dimensional coordinate system having a first axis, a second axis, and a third axis. The vibration surface information acquisition step involves acquiring information related to the vibration surface from the three-dimensional Lissajous figure generated in the Lissajous figure generation step. as well as The diagnostic step, based on the information related to the vibration surface obtained in the vibration surface information acquisition step, diagnoses the state of the object under diagnosis. In the step of obtaining vibration surface information, among multiple planes that face different directions, the plane with the smallest error obtained by approximating each point of the three-dimensional Lisajous figure projected onto the plane using the least squares method is taken as the vibration surface.

2. The diagnostic method according to claim 1, characterized in that, In the diagnostic step, the state of the diagnostic object is diagnosed based on the change in the shape of the three-dimensional Lisajous figure observed from the in-plane direction of the vibration surface over time.

3. The diagnostic method according to claim 1, characterized in that, In the diagnostic step, the state of the object to be diagnosed is determined based on the change in the shape of the three-dimensional Lisajous figure observed from the normal direction of the vibration surface over time.

4. The diagnostic method according to claim 1, characterized in that, In the diagnostic step, the state of the object under diagnosis is diagnosed based on the change in the tilt of the vibrating surface over time.

5. The diagnostic method according to any one of claims 1 to 4, characterized in that, The vibration surface can also be determined by: among multiple planes that face different directions, the plane with the largest area of ​​the three-dimensional Lisajous figure projected onto the plane is taken as the vibration surface.

6. The diagnostic method according to any one of claims 1 to 4, characterized in that, The vibration surface can also be determined by taking the surface orthogonal to the vector obtained by summing the vectors at each point of the three-dimensional Lissajous figure per unit time as the vibration surface.

7. A diagnostic device, characterized in that, Perform the following steps: The physical quantity detection step involves using a physical quantity sensor to detect the physical quantities generated by the object being diagnosed. The Lissajous figure generation step generates a three-dimensional Lissajous figure by depicting the physical quantity detected in the physical quantity detection step in a three-dimensional coordinate system having a first axis, a second axis, and a third axis. The vibration surface information acquisition step involves acquiring information related to the vibration surface from the three-dimensional Lissajous figure generated in the Lissajous figure generation step. as well as The diagnostic step, based on the information related to the vibration surface obtained in the vibration surface information acquisition step, diagnoses the state of the object under diagnosis. In the step of obtaining vibration surface information, among multiple planes that face different directions, the plane with the smallest error obtained by approximating each point of the three-dimensional Lisajous figure projected onto the plane using the least squares method is taken as the vibration surface.

8. A diagnostic system, characterized in that, have: Physical quantity sensors detect physical quantities generated by the object being diagnosed; and The diagnostic device diagnoses the state of the object being diagnosed based on the detection signals from the physical quantity sensor. The diagnostic device performs the following steps: The physical quantity detection step involves using a physical quantity sensor to detect the physical quantities generated by the object being diagnosed. The Lissajous figure generation step generates a three-dimensional Lissajous figure by depicting the physical quantities detected in the physical quantity detection step in a three-dimensional coordinate system of the first axis, the second axis, and the third axis. The vibration surface information acquisition step involves acquiring information related to the vibration surface from the three-dimensional Lissajous figure generated in the Lissajous figure generation step. as well as The diagnostic step, based on the information related to the vibration surface obtained in the vibration surface information acquisition step, diagnoses the state of the object under diagnosis. In the step of obtaining vibration surface information, among multiple planes that face different directions, the plane with the smallest error obtained by approximating each point of the three-dimensional Lisajous figure projected onto the plane using the least squares method is taken as the vibration surface.

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