JP7843170B2 - Condition monitoring device and diagnostic device, and condition monitoring method and diagnostic method - Google Patents

Description

This disclosure relates to a condition monitoring device and a diagnostic device, a condition monitoring method, and a diagnostic method.

In drive systems that use drive units to drive mechanical products, there is a need to diagnose the drive unit system by monitoring the current state variables within the drive unit system. A conventional diagnostic device is, for example, the technology described in Patent Document 1.

Japanese Patent Publication No. 2020-169924

The diagnostic device described in Patent Document 1 determines whether or not there is an abnormality in the phase surface data based on whether the phase surface data acquired during diagnosis is included in a threshold phase surface with a margin over the phase surface acquired under normal conditions. In this case, if the phase surface data is located outside the threshold phase surface, it can be determined that there is an abnormality in the phase surface data. On the other hand, if the phase surface data is located inside the threshold phase surface, it cannot be determined that there is an abnormality in the phase surface data. Therefore, it becomes difficult to diagnose the phase surface data with high accuracy.

This disclosure aims to solve the aforementioned problems and provide a condition monitoring device and method, as well as a diagnostic device and method, that enable high-precision diagnosis by monitoring the state quantities of a drive system.

To achieve the above objective, the state monitoring device disclosed herein comprises: a data acquisition unit for acquiring state quantities; a determination phase plane data creation unit for creating determination phase plane data based on the state quantities under normal conditions; a diagnostic phase plane data creation unit for creating diagnostic phase plane data based on the state quantities acquired during diagnosis; a phase plane data calculation unit for calculating the total displacement amount of the diagnostic phase plane data relative to the determination phase plane data; and an output unit for outputting the total displacement amount.

The diagnostic device of this disclosure comprises a condition monitoring device and an abnormality determination unit that compares the total displacement amount with a preset displacement amount determination value to determine whether or not an abnormality exists.

The state monitoring method disclosed herein comprises the steps of: acquiring state quantities; creating a determination phase plane based on the state quantities under normal conditions; creating a diagnostic phase plane based on the state quantities acquired during diagnosis; calculating the total displacement of the determination phase plane relative to the determination phase plane; and outputting the total displacement.

The diagnostic method of this disclosure includes the steps of: acquiring state quantities; creating a judgment phase surface based on the state quantities under normal conditions; creating a diagnostic phase surface based on the state quantities acquired during diagnosis; calculating the total displacement of the judgment phase surface relative to the judgment phase surface; and determining whether or not an abnormality exists by comparing the total displacement with a preset displacement judgment value.

According to the condition monitoring device, diagnostic device, condition monitoring method, and diagnostic method disclosed herein, highly accurate diagnostics can be performed by monitoring the condition quantities of the drive system.

Figure 1 is a schematic diagram showing the overall configuration of the condition monitoring device according to the first embodiment. Figure 2 is a block diagram showing the functional configuration of the condition monitoring device. Figure 3 is an explanatory diagram illustrating a model of the drive system when a ground fault occurs. Figure 4 is a schematic diagram showing the phase plane data of the current as a function of the angular velocity of a motor used to determine the occurrence of a leakage current. Figure 5 is a schematic diagram showing the phase plane data of voltage against the angular velocity of a motor used to determine the occurrence of a leakage current. Figure 6 is an explanatory diagram illustrating a model of the drive system when a winding short circuit occurs. Figure 7 is a schematic diagram showing the phase plane data of the current as a function of the angular velocity of a motor used to determine the occurrence of a winding short circuit. Figure 8 is a schematic diagram showing the phase plane data of the voltage as a function of the angular velocity of a motor used to determine the occurrence of a winding short circuit. Figure 9 is a schematic diagram showing the phase plane data of the current as a function of the motor's angular velocity, which is used to determine the increase in friction. Figure 10 is a schematic diagram showing the phase plane data of voltage against the angular velocity of a motor used to determine friction increase. Figure 11 is an explanatory diagram illustrating the method for calculating the total displacement. Figure 12 is an explanatory diagram illustrating the method for calculating the displacement in the X direction. Figure 13 is an explanatory diagram illustrating the method for calculating the displacement in the Y direction. Figure 14 is an explanatory diagram illustrating a modified example of the method for calculating the total displacement. Figure 15 is an explanatory diagram showing the current value and position over time. Figure 16 is a flowchart illustrating the status monitoring method and the diagnostic method. Figure 17 is a flowchart illustrating modified examples of the condition monitoring method and the diagnostic method. Figure 18 is a schematic diagram showing the overall configuration of the diagnostic device according to the second embodiment. Figure 19 is a flowchart illustrating the diagnostic method. Figure 20 is a schematic diagram illustrating the condition monitoring device and diagnostic device of the third embodiment.

Preferred embodiments of this disclosure will be described in detail below with reference to the drawings. However, this embodiment does not limit the disclosure, and where there are multiple embodiments, they may be combinations of these embodiments. Furthermore, the components in the embodiments include those readily conceivable by those skilled in the art, those that are substantially identical, and those within the so-called equivalent range.

[First Embodiment]
<Overall configuration of the condition monitoring system>
Figure 1 is a schematic diagram showing the overall configuration of the condition monitoring device according to the first embodiment.

As shown in Figure 1, the drive system 10 includes a motor 11, a rotating shaft 12 as a connecting member, and a load 13. The rotating shaft 12 is rotatably supported by a case (bearing) 14. A motor amplifier 21 is connected to the motor 11, and a motor control unit 22 is connected to the motor amplifier 21.

The motor control unit 22 receives command values such as the angle, angular velocity, and torque of the load 13 as input, and outputs these command values as command signals to the motor amplifier 21. The motor amplifier 21 supplies the necessary power based on the command values. The motor amplifier 21 then receives the actual angle, angular velocity, and torque of the motor 11 as input, detected by various sensors located inside the motor 11. The motor amplifier 21 performs feedback control of the motor 11 based on the actual position, speed, and torque of the input load 13.

Furthermore, while the above description states that the drive system 10 transmits the rotational force of the motor 11 to the load 13 via the rotating shaft 12, thereby rotating the load 13, the system is not limited to this configuration. For example, the drive system 10 may transmit the rotational force of the motor 11 to the load 13 via a connecting member including the rotating shaft 12, thereby causing the load 13 to move linearly.

Furthermore, the motor 11 is equipped with an angular velocity sensor 23, a current sensor 24, and a voltage sensor 25. The angular velocity sensor 23, current sensor 24, and voltage sensor 25 are connected to the motor control unit 22. The angular velocity sensor 23 measures the angular velocity ω of the motor 11 and outputs it to the motor control unit 22. The current sensor 24 measures the current (motor driver current) i of the motor 11 and outputs it to the motor control unit. The voltage sensor 25 measures the voltage (motor driver voltage) u of the motor 11 and outputs it to the motor control unit 22.

The motor control unit 22 is connected to the status monitoring device 30. The status monitoring device 30 receives the angular velocity ω, current i, and voltage u of the motor 11 from the motor control unit 22. Alternatively, the status monitoring device 30 may receive the angular velocity ω, current i, and voltage u of the motor 11 directly from the angular velocity sensor 23, current sensor 24, and voltage sensor 25. The status monitoring device 30 monitors the status of the drive system based on the angular velocity ω, current i, and voltage u of the motor 11.

Furthermore, the control device, which functions as the motor control unit 22, is a controller, and is realized by executing various programs stored in the memory unit using RAM as the working area, for example, using a CPU (Central Processing Unit) or MPU (Micro Processing Unit).

<Condition monitoring device>
Figure 2 is a block diagram showing the functional configuration of the condition monitoring device.

The status monitoring device 30 comprises a status monitoring control unit 31, an operation unit 32, a display unit (output unit) 33, and a storage unit 34.

The state monitoring control unit 31 determines changes in the state of the motor 11 based on the angular velocity ω, current i, and voltage u input from the motor control unit 22, and monitors for abnormalities. The control device, as the state monitoring control unit 31, is a controller, and is realized, for example, by a CPU (Central Processing Unit) or MPU (Micro Processing Unit) executing various programs stored in the memory unit using RAM as the working area.

The operation unit 32 allows the operator to input various operation commands and data to the state monitoring control unit 31. The operation unit 32 is, for example, a keyboard, mouse, or touch-sensitive display. The display unit 33 can display the processing content of the state monitoring control unit 31. The display unit 33 functions as an output unit, displaying the judgment phase plane data and diagnostic phase plane data described later. The display unit 33 is, for example, a monitor implemented by a display. The output unit may also be, for example, a printer. The storage unit 34 stores various programs executed by the state monitoring control unit 31. These programs include a program for analyzing the state of the motor 11. The storage unit 34 also stores the analysis results performed by the state monitoring control unit 31.

Furthermore, the state monitoring and control unit 31 includes a data acquisition unit 41, a phase plane data creation unit 42 for determination, a phase plane data creation unit 43 for diagnosis, and a phase plane data calculation unit 44.

The data acquisition unit 41 acquires various state variables of the drive system 10, which is the target of monitoring. The data acquisition unit 41 acquires the angular velocity ω, current i, and voltage u of the motor 11 from the motor control unit 22.

The phase plane data creation unit 42 creates phase plane data for determination based on the normal state variables of the drive system 10. The phase plane data creation unit 42 also creates phase plane data for determination based on the angular velocity ω, current i, and voltage u of the motor 11 acquired by the data acquisition unit 41. Furthermore, the phase plane data creation unit 42 creates phase plane data for determination based on the angular velocity ω, current i, and voltage u of the motor 11 as previously acquired state variables.

Specifically, the phase plane data creation unit 42 uses previously created phase plane data as the phase plane data for determination. In this case, for example, the phase plane data for determination is the phase plane data created based on the state variables (initial state variables) before the start of use of the drive system 10. Alternatively, for example, the phase plane data for determination is the phase plane data created based on the state variables (appropriate state variables) adjusted after the start of use of the drive system 10. In other words, the phase plane data creation unit 42 uses the phase plane data created when the drive system 10 was operating normally as the phase plane data for determination.

Furthermore, the phase plane data creation unit 42 for determination is not limited to creating phase plane data for determination using the method described above. For example, the phase plane data for determination may be average phase plane data obtained by averaging multiple phase plane data created from the start of use of the drive system 10 up to a predetermined period. In this case, the predetermined period from the start of use may be the period from the start of use up to immediately before diagnosis, or the period from the start of use up to a predetermined month and year of use. That is, it is preferable that it be the period during which the drive system 10 was operating normally from the start of use up to immediately before diagnosis.

Furthermore, for example, the phase plane data used for judgment may be either the maximum phase plane data created in the past, or the minimum phase plane data created in the past. Phase plane data contains a certain degree of variation even within the normal range. By plotting the data accumulated during periods of normal operation on the phase plane and connecting the outermost plots in order, the outer contour of the region where the data is plotted can be extracted. This represents the maximum possible region of the phase plane at that time, i.e., the maximum phase plane data, and therefore, any phase plane containing plots outside this can be judged as abnormal. Conversely, the minimum phase plane data is obtained by connecting the innermost plots in order, extracting the inner contour of the region where the data is plotted, and therefore, any phase plane containing plots inside this can be judged as abnormal.

Furthermore, the phase plane data creation unit 42 may be pre-programmed with a comprehensive list of abnormal conditions for the drive system 10 (such as leakage current, winding short circuits, and increased friction), and the phase plane data for determination may be created through simulation or experimentation. The phase plane data for determination may also be trained using machine learning methods such as deep learning.

The diagnostic phase plane data creation unit 43 creates diagnostic phase plane data based on the state variables acquired during the diagnosis. The diagnostic phase plane data creation unit 43 creates diagnostic phase plane data based on the angular velocity ω, current i, and voltage u of the motor 11, which are state variables acquired during the diagnosis. Here, the state variables acquired during the diagnosis are the current state variables or the state variables at a predetermined point in the past.

In this embodiment, the state variables of the drive system 10 acquired by the data acquisition unit 41 are the angular velocity ω, current i, and voltage u of the motor 11. The determination phase plane data creation unit 42 and the diagnostic phase plane data creation unit 43 create at least one of the following: first phase plane data for current i relative to angular velocity ω, and second phase plane data for voltage u relative to angular velocity ω. Specifically, the determination phase plane data creation unit 42 creates first determination phase plane data for current i relative to angular velocity ω, and second determination phase plane data for voltage u relative to angular velocity ω. The diagnostic phase plane data creation unit 43 also creates first diagnostic phase plane data for current i relative to angular velocity ω, and second diagnostic phase plane data for voltage u relative to angular velocity ω. Note that, if necessary, only the first phase plane data or only the second phase plane data may be created.

The phase plane data calculation unit 44 calculates the total displacement of the diagnostic phase plane data created by the diagnostic phase plane data creation unit 43 relative to the judgment phase plane data created by the judgment phase plane data creation unit 42. The phase plane data calculation unit 44 also calculates the total displacement of the first diagnostic phase plane data relative to the first judgment phase plane data. Furthermore, the phase plane data calculation unit 44 calculates the total displacement of the second diagnostic phase plane data relative to the second judgment phase plane data. The display unit 33 displays the two calculation results: the total displacement of the first diagnostic phase plane data relative to the first judgment phase plane data, and the total displacement of the second diagnostic phase plane data relative to the second judgment phase plane data. The operator can monitor the leakage current displacement, winding short circuit displacement, and friction displacement in the drive system 10 using the display unit 33.

Here, the phase plane data calculation unit 44 calculates the total displacement of the diagnostic phase plane data relative to the determination phase plane data. The total displacement is, for example, the displacement of the centroid of the diagnostic phase plane data relative to the centroid of the determination phase plane data. Furthermore, the total displacement is, for example, the displacement of multiple fixed points set in the diagnostic phase plane data relative to multiple fixed points set in the determination phase plane data. In this case, it is preferable that the multiple fixed points sample values from the same time on the time axis.

<Phase plane data for leakage detection>
Figure 3 is an explanatory diagram representing a model of the drive system when a leakage current occurs, Figure 4 is a schematic diagram representing the phase plane data of the current with respect to the angular velocity of the motor used to determine the occurrence of a leakage current, and Figure 5 is a schematic diagram representing the phase plane data of the voltage with respect to the angular velocity of the motor used to determine the occurrence of a leakage current.

As shown in Figure 3, when an armature resistance _RM is provided in the current path of the motor 11, the current i _M is obtained. Here, leakage current in the drive system 10 is caused by the occurrence of a different current path (leakage path) in the current path after the output of the motor driver, and includes insulation failure of the motor 11, etc. That is, a leakage resistance _RL is generated in the current path of the motor 11, and a leakage current i _L flows. The leakage current generation model in this case is shown by the following equation. Here, Ke is the back electromotive force constant.

The equation of motion is given by the following formula, where Kt is the torque constant.
By eliminating the current i _M from equations (1) and (3), and solving the equation for voltage u, we obtain equation (4).

Here, the leakage rate _μL is expressed by formula (5) as a parameter for evaluating leakage current.
Equation (5) represents the phase plane data of angular velocity ω and voltage u as measurable state variables, and does not include the leakage rate _μL as a parameter for leakage current. Therefore, it is not possible to determine the occurrence of leakage current from the phase plane data of angular velocity ω and voltage u.

On the other hand, we obtain the phase plane data of the angular velocity ω and current i as state variables. For angular velocity ω and current i, we can obtain equation (6).
Equation (6) represents the phase plane data of angular velocity ω and current i as measurable state variables, and since all terms are affected by the leakage current parameter (leakage rate _μL ), it is possible to determine the occurrence of leakage current from the phase plane data of angular velocity ω and current i.

The first phase plane data shown in Figure 4 represents the change in current i in response to a change in angular velocity ω. Specifically, in region A, the current i supplied to motor 11 increases in one direction, causing motor 11 to begin forward rotation. In region B, the angular velocity ω (rotational speed) of motor 11 increases, and the torque also increases gradually. Between region B and region C, the current i supplied to motor 11 becomes constant, and the angular velocity ω of motor 11 also becomes constant. Then, in region C, the current i supplied to motor 11 decreases sharply, and the angular velocity ω of motor 11 also decreases. In region D, the current i supplied to motor 11 decreases gradually, and the angular velocity ω of motor 11 also decreases.

As shown in Figure 4, the phase plane data for determination is represented by a solid line, and the phase plane data for diagnosis is represented by a dashed line. In the first phase plane data of angular velocity ω and current i, when a leakage current occurs, the current i is displaced upward as the angular velocity ω increases. That is, in regions B, C, and D, the diagnostic phase plane data is displaced upward relative to the phase plane data for determination. In other words, in region B, the diagnostic phase plane data is displaced outside the phase plane data for determination; in region C, the diagnostic phase plane data is displaced outside the phase plane data for determination; and in region D, the diagnostic phase plane data is displaced inside the phase plane data for determination.

The first phase plane data shown in Figure 5 represents the change in voltage u in response to a change in angular velocity ω. Specifically, in region A, the voltage u supplied to motor 11 increases in one direction, initiating forward rotation. In region B, the voltage u supplied to motor 11 increases gradually, and the angular velocity ω (rotational speed) of motor 11 also increases. Between region B and region C, the voltage u supplied to motor 11 becomes constant, and the angular velocity ω (rotational speed) of motor 11 also becomes constant. Then, in region C, the voltage u supplied to motor 11 decreases sharply, and motor 11 begins to decelerate. In region D, the voltage u supplied to motor 11 decreases gradually, and the angular velocity ω (rotational speed) of motor 11 also decreases.

As shown in Figure 5, the phase plane data for determination is represented by a solid line. In the second phase plane data of angular velocity ω and voltage u, even if leakage current occurs, the voltage u does not change as the angular velocity ω increases. That is, in all regions A, B, C, and D, the diagnostic phase plane data does not change relative to the phase plane data for determination.

<Phase plane data for winding short circuit detection>
Figure 6 is an explanatory diagram representing a model of the drive system when a winding short occurs, Figure 7 is a schematic diagram representing the phase plane data of the current against the angular velocity of the motor used to determine if a winding short occurs, and Figure 8 is a schematic diagram representing the phase plane data of the voltage against the angular velocity of the motor used to determine if a winding short occurs.

As shown in Figure 6, the changes in the identified values of the armature resistance _RM and the back electromotive force constant Ke are investigated through analysis. A portion of the winding is short-circuited, and the short-circuited portion is denoted by the short-circuit ratio λ(0 to 1), and the effective portion of the armature resistance _RM is represented by _RM (1-λ). At this time, the back electromotive force constant Ke also decreases by the same ratio, so it is represented by Ke(1-λ). In this case, the winding short-circuit generation model is shown by the following equation.
Since the generated torque decreases due to the winding short circuit, the torque constant Kt is corrected in the same way as the back electromotive force constant Ke mentioned above. That is, the torque constant Kt is corrected to Kt(1-λ).
Solving equations (7) and (8) for angular velocity ω and voltage u, we obtain equation (9).

Equation (9) represents the phase-plane data of angular velocity ω and voltage u as measurable state variables. Since it includes the winding short-circuit ratio λ, the occurrence of a winding short can be determined from the phase-plane data of angular velocity ω and voltage u.

On the other hand, we obtain the phase plane data of the angular velocity ω and current i as state variables. For angular velocity ω and current i, we can obtain equation (10).
Equation (10) represents the phase plane data of angular velocity ω and current i as measurable state variables, and since it includes the winding short-circuit ratio λ, it is possible to determine the occurrence of a winding short circuit from the phase plane data of angular velocity ω and current i.

As shown in Figure 7, the phase plane data for determination is represented by a solid line, and the phase plane data for diagnosis is represented by a dashed line. In the first phase plane data of angular velocity ω and current i, when a winding short circuit occurs, the current i is displaced upward. That is, in regions B and D, the diagnostic phase plane data is displaced upward relative to the determination phase plane data. In other words, in region B, the diagnostic phase plane data is displaced outside the determination phase plane data, and in region D, the diagnostic phase plane data is displaced inside the determination phase plane data.

As shown in Figure 8, in the second phase plane data of angular velocity ω and voltage u, when a winding short circuit occurs, the voltage u is displaced downward. That is, in regions B and D, the diagnostic phase plane data is displaced downward relative to the determination phase plane data. In other words, in region B, the diagnostic phase plane data is displaced outside the determination phase plane data, passing inside it, and in region D, the diagnostic phase plane data is displaced outside the determination phase plane data.

<Phase surface data for detecting increased friction>
Figure 9 is a schematic diagram showing the phase plane data of the current as a function of the angular velocity of the motor used to determine the increase in friction, and Figure 10 is a schematic diagram showing the phase plane data of the voltage as a function of the angular velocity of the motor used to determine the increase in friction.

Solving the rolling equation for current i yields equation (11).
Since the increase in friction is affected by the increase in angular velocity ω, the increase in friction can be determined from the phase plane data of angular velocity ω and voltage u, and the phase plane data of angular velocity ω and current i.

As shown in Figure 9, the phase plane data for determination is represented by a solid line, and the phase plane data for diagnosis is represented by a dashed line. In the first phase plane data of angular velocity ω and current i, when friction increases, the current i is displaced upward. That is, in regions B and D, the diagnostic phase plane data is displaced upward relative to the phase plane data for determination. In other words, in region B, the diagnostic phase plane data is displaced outside the phase plane data for determination, and in region D, the diagnostic phase plane data is displaced inside the phase plane data for determination.

As shown in Figure 10, in the second phase plane data of angular velocity ω and voltage u, when friction increases, the voltage u is displaced upward. That is, in regions B and D, the diagnostic phase plane data is displaced upward relative to the determination phase plane data. In other words, in region B, the diagnostic phase plane data is displaced outside the determination phase plane data, passing inside it, and in region D, the diagnostic phase plane data is displaced outside the determination phase plane data.

<Method for calculating the total displacement amount>
Figure 11 is an explanatory diagram showing the method for calculating the total displacement, Figure 12 is an explanatory diagram showing the method for calculating the displacement in the X direction, and Figure 13 is an explanatory diagram showing the method for calculating the displacement in the Y direction.

The phase plane data calculation unit 44 calculates the total displacement of the diagnostic phase plane data relative to the determination phase plane data. Here, the total displacement is the displacement of the centroid of the diagnostic phase plane data relative to the centroid of the determination phase plane data. The centroids of the determination phase plane data and the centroid of the diagnostic phase plane data will be explained below.

As shown in Figure 11, if state variable 1 is X and state variable 2 is Y, then the determination phase plane data 101 and the diagnostic phase plane data 111 are two-dimensional data. Here, state variable 1 (X) is, for example, angular velocity ω, and state variable 2 (Y) is current i or voltage u. The determination phase plane data 101 has a centroid 102, and the diagnostic phase plane data 111 has a centroid 112. The centroids 102 and 112 are the points where the respective figures of the determination phase plane data 101 and the diagnostic phase plane data 111 balance when their positions are used as pivot points.

As shown in Figures 12 and 13, for example, the determination phase surface data 101 is divided in the X direction into multiple regions 101x that form a strip shape along the Y direction. That is, the determination phase surface data 101 is obtained by integrating each region 101x in the X direction. Similarly, the determination phase surface data 101 is divided in the Y direction into multiple regions 101y that form a strip shape along the X direction. That is, the determination phase surface data 101 is obtained by integrating each region 101y in the Y direction. Then, the centroid 102 of the determination phase surface data 101 is calculated using the following formulas for its position in the X direction and Y direction.

The centroid 122 of the diagnostic phase plane data 111 is also calculated in the same way, with its position in the X and Y directions.

Once the XY positions of the centroid 102 of the determination phase plane data 101 and the XY positions of the diagnostic phase plane data 111 are calculated, the displacement amount D is calculated based on the deviation between the XY positions of the centroid 102 of the determination phase plane data 101 and the XY positions of the diagnostic phase plane data 111.

Furthermore, the total displacement is not limited to the displacement of the centroid of the diagnostic phase plane data relative to the centroid of the judgment phase plane data.

The total displacement may be the displacement of multiple fixed points set in the diagnostic phase surface data relative to multiple fixed points set in the judgment phase surface data.

As shown in Figure 14, if state variable 1 is X and state variable 2 is Y, then the determination phase plane data 121 and the diagnostic phase plane data 131 are two-dimensional data. Here, state variable 1 (X) is, for example, angular velocity ω, and state variable 2 (Y) is current i or voltage u. The determination phase plane data 101 has multiple (eight in this embodiment) fixed points 141, 142, 143, 144, 145, 146, 147, and 148.

The diagnostic phase plane data 131 has a total displacement amount between it and the judgment phase plane data 121. That is, multiple fixed points 141, 142, 143, 144, 145, 146, 147, and 148 move between the judgment phase plane data 121 and the diagnostic phase plane data 131. The displacement amounts Da, Db, Dc, Dd, De, Df, Dg, and Dh of the multiple fixed points 141, 142, 143, 144, 145, 146, 147, and 148 are calculated between the judgment phase plane data 121 and the diagnostic phase plane data 131. The method for calculating the displacement amounts Da, Db, Dc, Dd, De, Df, Dg, and Dh is the method described above. The total displacement amount can be expressed as a vector quantity based on the displacement amounts Da, Db, Dc, Dd, De, Df, Dg, and Dh.

Furthermore, in order to determine the total displacement, when calculating the displacement of multiple fixed points set in the diagnostic phase surface data relative to multiple fixed points set in the judgment phase surface data, each fixed point in the phase surface can be sampled at the same time on the time axis. As an explanation, Figure 15 shows an example where angular velocity ω and current i are sampled from fixed point 145 to 148. For example, fixed point 145 of the judgment phase surface data in Figure 14 is plotted based on the angular velocity ω and current i at fixed point 145 during judgment. Similarly, by calculating the displacement between the fixed point in the diagnostic phase surface data plotted based on the angular velocity ω and current i at fixed point 145 during diagnosis and fixed point 145 of the judgment phase surface data, the displacement amount De can be obtained.

<Methods for monitoring and diagnosing the condition>
Figure 16 is a flowchart illustrating the status monitoring method and the diagnostic method.

As shown in Figures 2 and 16, in step S11, the data acquisition unit 41 acquires the angular velocity ω, current i, and voltage u of the motor 11 as various state quantities of the drive system 10. In step S12, the determination phase plane data creation unit 42 creates determination phase plane data based, for example, on previously created phase plane data. The determination phase plane data is the phase plane data created when the drive system 10 was operating normally. Here, the determination phase plane data consists of, for example, first determination phase plane data of angular velocity ω and current i, and second determination phase plane data of angular velocity ω and voltage u.

In step S13, the diagnostic phase plane data creation unit 43 creates diagnostic phase plane data based on the state variables (angular velocity ω, current i, voltage u) acquired during the diagnosis. The diagnosis refers to a specific time in the present or past. Here, the diagnostic phase plane data includes, for example, first diagnostic phase plane data of angular velocity ω and current i, and second diagnostic phase plane data of angular velocity ω and voltage u.

In step S14, the phase plane data calculation unit 44 calculates the total displacement amount of the diagnostic phase plane data created by the diagnostic phase plane data creation unit 43 relative to the judgment phase plane data created by the judgment phase plane data creation unit 42. Then, in step S15, the display unit 33 displays the judgment phase plane data and the diagnostic phase plane data output from the phase plane data calculation unit 44, overlaid on top of each other.

In other words, the display unit 33 overlays the first phase surface data for judgment and the first phase surface data for diagnosis, and also overlays the second phase surface data for judgment and the second phase surface data for diagnosis. Therefore, it becomes possible to monitor the total first displacement amount of the first phase surface data for judgment and the first phase surface data for diagnosis, and the total second displacement amount of the second phase surface data for judgment and the second phase surface data for diagnosis.

In step S16, the operator checks the total first displacement amount of the first phase surface data for determination and the first phase surface data for diagnosis, and the total second displacement amount of the second phase surface data for determination and the second phase surface data for diagnosis, displayed on the display unit 33. Based on this, the operator compares the displacement amounts for leakage current, winding short circuit, and friction in the drive system 10 with preset determination values. If the operator determines that the displacement amounts for leakage current, winding short circuit, and friction are smaller than the determination values, the operator determines that the drive system 10 is functioning normally. On the other hand, if the operator determines that the displacement amounts for leakage current, winding short circuit, and friction are larger than the determination values, the operator determines that there is an abnormality due to leakage current, winding short circuit, or increased friction.

<Variations of condition monitoring and diagnostic methods>
The status monitoring and diagnostic methods are not limited to those described above. Figure 17 is a flowchart showing a modified example of the status monitoring and diagnostic methods.

As shown in Figures 2 and 17, in step S21, the data acquisition unit 41 acquires the angular velocity ω, current i, and voltage u of the motor 11 as various state quantities of the drive system 10. In step S22, the determination phase plane data creation unit 42 comprehensively provides conditions for abnormalities in the drive system 10 (e.g., leakage current, winding short circuit, increased friction) in advance and creates determination phase plane data through simulation or experimentation. Here, the determination phase plane data consists of, for example, first determination phase plane data of angular velocity ω and current i, and second determination phase plane data of angular velocity ω and voltage u.

In step S23, the diagnostic phase plane data creation unit 43 creates diagnostic phase plane data based on the state variables (angular velocity ω, current i, voltage u) acquired during the diagnosis. Here, the diagnostic phase plane data includes, for example, first diagnostic phase plane data of angular velocity ω and current i, and second diagnostic phase plane data of angular velocity ω and voltage u.

In step S24, the phase plane data calculation unit 44 calculates the total displacement amount of the diagnostic phase plane data created by the diagnostic phase plane data creation unit 43 relative to the judgment phase plane data created by the judgment phase plane data creation unit 42. Then, in step S25, the display unit 33 displays the judgment phase plane data and the diagnostic phase plane data output from the phase plane data calculation unit 44, superimposed on each other. Note that the display of the judgment phase plane data and the diagnostic phase plane data by the display unit 33 may be omitted at this point.

In step S26, the state monitoring control unit 31 monitors the image data of the first phase surface data for determination and the image data of the first phase surface data for diagnosis. Then, using machine learning such as deep learning, it monitors the displacement of leakage current, winding short circuit, and friction in the drive system 10 based on the total displacement of the second phase surface data for determination and the second phase surface data for diagnosis. As a result, the normal or abnormal state of the drive system 10 is determined.

[Second Embodiment]
Figure 18 is a schematic diagram showing the overall configuration of the diagnostic device of the second embodiment, and Figure 19 is a flowchart showing the diagnostic method. Components having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and detailed explanations are omitted.

As shown in Figure 18, the diagnostic device 50 includes a diagnostic control unit 51, an operation unit 32, a display unit 33, and a storage unit 34. The state monitoring control unit 31A includes a data acquisition unit 41, a phase plane data creation unit 42 for determination, a phase plane data creation unit 43 for diagnosis, a phase plane data calculation unit 44, and an abnormality determination unit 45.

The operation unit 32, display unit 33, storage unit 34, data acquisition unit 41, judgment phase plane data creation unit 42, diagnostic phase plane data creation unit 43, and phase plane data calculation unit 44 are the same as in the first embodiment.

The abnormality determination unit 45 compares the total displacement amount calculated by the phase plane data calculation unit 44 with a preset displacement amount determination value to determine whether the drive system 10 is abnormal or not.

The total displacement is the displacement between the phase plane data used for judgment and the phase plane data used for diagnosis. Specifically, the phase plane data consists of a first phase plane data set of angular velocity ω and current i, and a second phase plane data set of angular velocity ω and current i. Therefore, the total displacement is the first displacement between the first judgment phase plane data and the first diagnosis phase plane data, and the second displacement between the second judgment phase plane data and the second diagnosis phase plane data.

In this embodiment, the total displacement is determined as the phase surface movement vector. That is, the relationship between the phase surface data movement vector and the leakage rate _μL , winding short-circuit rate λ, and friction Tf of the drive system 10 is determined by testing or simulation and expressed as a function. Here, an appropriate method can be used for expressing the relationship, such as the response surface method (response surface approximation), partial least squares regression method, or principal component regression method.

In other words, by formulating a function for the relationship between the phase surface data's movement vector and the leakage rate _μL , winding short-circuit rate λ, and friction Tf, the first movement vector δV1 of the first phase surface data (i-ω) and the second movement vector δV2 of the second phase surface data (u-ω) are obtained as the total displacement. Then, the state of the leakage rate _μL , winding short-circuit rate λ, and friction Tf are estimated from these two movement vectors δV1 and δV2.
Leakage rate μ _L = F1 (δV1, δV2)
Winding short-circuit ratio λ = F2(δV1, δV2)
Friction Tf=F3 (δV1, δV2)

Therefore, the abnormality determination unit 45 compares the leakage rate _μL as the total displacement, the winding short-circuit rate λ, and the friction Tf with the leakage rate determination value μth, the winding short-circuit rate determination value λth, and the friction determination value Tth, which are predetermined displacement determination values, to determine an abnormality in the drive system 10.

As shown in Figures 18 and 19, in step S31, the data acquisition unit 41 acquires the angular velocity ω, current i, and voltage u of the motor 11 as various state quantities of the drive system 10. In step S32, the determination phase plane data creation unit 42 creates determination phase plane data based, for example, on previously created phase plane data. Here, the determination phase plane data consists of, for example, first determination phase plane data of angular velocity ω and current i, and second determination phase plane data of angular velocity ω and voltage u.

In step S33, the diagnostic phase plane data creation unit 43 creates diagnostic phase plane data based on the state variables (angular velocity ω, current i, voltage u) acquired during the diagnosis. Here, the diagnostic phase plane data includes, for example, first diagnostic phase plane data of angular velocity ω and current i, and second diagnostic phase plane data of angular velocity ω and voltage u.

In step S34, the phase plane data calculation unit 44 calculates the total displacement amount of the diagnostic phase plane data created by the diagnostic phase plane data creation unit 43 relative to the judgment phase plane data created by the judgment phase plane data creation unit 42. Then, in step S35, the display unit 33 displays the judgment phase plane data and the diagnostic phase plane data output from the phase plane data calculation unit 44, overlaid on top of each other.

In step S36, the abnormality determination unit 45 calculates the movement vector of the diagnostic phase surface data. That is, by formulating a function for the relationship between the movement vector of the phase surface data and the leakage rate _μL , winding short circuit rate λ, and friction Tf of the drive system 10, the first movement vector δV1 of the first phase surface data (i-ω) and the second movement vector δV2 of the second phase surface data (u-ω) are obtained. In step S37, the state of the leakage rate _μL , winding short circuit rate λ, and friction Tf are estimated from the movement vectors δV1 and δV2 as the displacement amount of the diagnostic phase surface data.
Leakage rate μ _L = F1 (δV1, δV2)
Winding short-circuit ratio λ = F2(δV1, δV2)
Friction Tf=F3 (δV1, δV2)

Then, in step S38, the abnormality determination unit 45 determines whether the leakage rate _μL is greater than a preset leakage rate determination value μth. Here, the leakage rate determination value μth is set by testing or simulation based on past state variables and phase plane data. If the abnormality determination unit 45 determines that the leakage rate _μL is not greater than the leakage rate determination value μth (No), then in step S39, it determines that the drive system 10 is normal. On the other hand, if the abnormality determination unit 45 determines that the leakage rate _μL is greater than the leakage rate determination value μth (Yes), then in step S40, it determines that the drive system 10 is abnormal.

Furthermore, in step S41, the abnormality determination unit 45 determines whether the winding short-circuit ratio λ is greater than a preset winding short-circuit ratio determination value λth. Here, the winding short-circuit ratio determination value λth is set based on past state variables and phase plane data through testing or simulation. If the abnormality determination unit 45 determines that the winding short-circuit ratio λ is not greater than the winding short-circuit ratio determination value λth (No), then in step S42, it determines that the drive system 10 is normal. On the other hand, if the abnormality determination unit 45 determines that the winding short-circuit ratio λ is greater than the winding short-circuit ratio determination value λth (Yes), then in step S43, it determines that the drive system 10 is abnormal.

Furthermore, in step S44, the abnormality determination unit 45 determines whether the friction Tf is greater than a preset friction determination value Tth. Here, the friction determination value Tth is set based on past state variables and phase surface data through testing or simulation. If the abnormality determination unit 45 determines that the friction Tf is not greater than the friction determination value Tth (No), then in step S45, it determines that the drive system 10 is normal. On the other hand, if the abnormality determination unit 45 determines that the friction Tf is greater than the friction determination value Tth (Yes), then in step S46, it determines that the drive system 10 is abnormal.

[Third Embodiment]
Figure 20 is a schematic diagram illustrating the condition monitoring device and diagnostic device of the third embodiment. Components having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and detailed descriptions are omitted.

As shown in Figure 20, in the first and second embodiments, the state monitoring device 30 and the diagnostic device 50 monitor or diagnose the state of the drive system 10 based on the angular velocity ω, current i, and voltage u of the motor 11. At this time, the phase plane data processed consists of first phase plane data of angular velocity ω and current i, and second phase plane data of angular velocity ω and voltage u. The first and second phase plane data are two-dimensional data.

In the third embodiment, as shown in Figure 20, the first and second phase plane data are treated as three-dimensional data (multidimensional data). The determination phase plane data 151 is three-dimensional phase plane data of state variables X, Y, and Z. Similarly, the diagnostic phase plane data 152 is three-dimensional phase plane data of state variables X, Y, and Z. Here, state variables X, Y, and Z are, for example, angular velocity ω, current i, and voltage u. The phase plane data calculation unit 44 (see Figure 18) calculates the total displacement in the three-dimensional direction of the determination phase plane data 151 and the diagnostic phase plane data 152. The abnormality determination unit 45 (see Figure 18) compares the total displacement in the three-dimensional direction with the displacement determination value in the three-dimensional direction to determine an abnormality. The calculation direction for the total displacement in the three-dimensional direction is the same as the calculation method for the total displacement in the two-dimensional direction.

In this case, the state variables could be multidimensional, combining control deviation e, currents for each phase of a three-phase motor, etc., as controls for the control device.

[Effects of this embodiment]
The state monitoring device according to the first embodiment includes a data acquisition unit 41 that acquires state quantities, a determination phase plane data creation unit 42 that creates determination phase plane data based on state quantities acquired in the past, a diagnostic phase plane data creation unit 43 that creates diagnostic phase plane data based on state quantities acquired during diagnosis, a phase plane data calculation unit 44 that calculates the total displacement amount of the diagnostic phase plane data relative to the determination phase plane data, and a display unit (output unit) 33 that outputs the total displacement amount.

According to the first embodiment of the condition monitoring device, the total displacement of the diagnostic phase surface data relative to the determination phase surface data is calculated and displayed, allowing for appropriate identification of abnormalities corresponding to the state quantities acquired during diagnosis. Specifically, the diagnostic phase surface data may be partially or entirely displaced relative to the determination phase surface data. In other words, the diagnostic phase surface data may be partially or entirely displaced outside or inside the determination phase surface data. By displaying the total displacement of the diagnostic phase surface data relative to the determination phase surface data, it is possible to detect displacements of the diagnostic phase surface data outside and inside the determination phase surface data. As a result, highly accurate diagnosis can be achieved by monitoring the state quantities of the drive system.

In the second embodiment of the state monitoring device, the total displacement is the displacement of the centroid of the diagnostic phase plane data relative to the centroid of the determination phase plane data. This allows for easy calculation of the total displacement.

In the third embodiment of the condition monitoring device, the total displacement is the displacement of multiple fixed points set in the diagnostic phase plane data relative to multiple fixed points set in the determination phase plane data. This allows for easy calculation of the total displacement.

In the fourth embodiment of the state monitoring device, the determination phase plane data creation unit 42 uses previously created phase plane data or average phase plane data obtained by averaging multiple previously created phase plane data as the determination phase plane data. This allows for a comparison between a specific past state of the drive system 10 and the state at the time of diagnosis by applying previously created phase plane data as the determination phase plane data. Furthermore, by applying average phase plane data as the determination phase plane data, a comparison between the state of the drive system, taking into account past state changes, and the state at the time of diagnosis is possible.

In the fifth embodiment of the state monitoring device, the determination phase plane data creation unit 42 uses previously created maximum or minimum phase plane data as the determination phase plane data. This allows for a comparison between a specific past state of the drive system 10 and the state at the time of diagnosis.

The sixth embodiment of the condition monitoring device has a display unit 33 that displays the total displacement amount by superimposing judgment phase plane data and diagnostic phase plane data. This allows the operator to easily diagnose abnormalities by visually observing the total displacement amount of the judgment phase plane data and diagnostic phase plane data on the display unit 33.

In the seventh embodiment of the state monitoring device, the data acquisition unit 41 acquires the motor's angular velocity ω, current i, and voltage u as state variables, and the determination phase plane data creation unit 42 and the diagnostic phase plane data creation unit 43 create at least one of a first phase plane data of current i relative to angular velocity ω and a second phase plane data of voltage u relative to angular velocity ω. This allows for appropriate determination of abnormalities in the drive system 10 based on the state variables of the motor 11.

The condition monitoring device according to the eighth embodiment includes a phase plane data calculation unit 44 that calculates the total first displacement amount of the diagnostic first phase plane data relative to the determination first phase plane data, and also calculates the total second displacement amount of the diagnostic second phase plane data relative to the determination second phase plane data. The display unit 33 displays the total first displacement amount and the total second displacement amount. This allows for appropriate determination of leakage current, winding short circuits, and friction abnormalities in the drive system 10 driven by the motor 11.

The diagnostic device according to the ninth embodiment includes a data acquisition unit 41 for acquiring state quantities, a determination phase plane data creation unit 42 for creating determination phase plane data based on previously acquired state quantities, a diagnostic phase plane data creation unit 43 for creating diagnostic phase plane data based on state quantities acquired during diagnosis, a phase plane data calculation unit 44 for calculating the total displacement amount of the diagnostic phase plane data relative to the determination phase plane data, and an abnormality determination unit 45 for determining whether an abnormality exists by comparing the total displacement amount with a preset displacement amount determination value. This allows for the detection of outward and inward displacements of the diagnostic phase plane data relative to the determination phase plane data by comparing the total displacement amount of the diagnostic phase plane data with the displacement amount determination value to determine an abnormality. As a result, highly accurate diagnosis can be achieved by monitoring the state quantities of the drive system.

In the diagnostic device according to the tenth embodiment, the abnormality determination unit 45 determines that an abnormality exists if the total displacement exceeds the displacement determination value. This enables highly accurate diagnosis of the drive system.

The state monitoring method according to the eleventh embodiment includes the steps of: acquiring state quantities; creating a determination phase surface based on previously acquired state quantities; creating a diagnostic phase surface based on state quantities acquired during diagnosis; calculating the total displacement of the determination phase surface relative to the determination phase surface; and outputting the total displacement. By calculating the total displacement of the diagnostic phase surface data relative to the determination phase surface data, it is possible to detect outward and inward displacements of the diagnostic phase surface data relative to the determination phase surface data. As a result, highly accurate diagnosis can be achieved by monitoring the state quantities of the drive system.

The diagnostic method according to the twelfth embodiment includes the steps of: acquiring state variables; creating a judgment phase surface based on previously acquired state variables; creating a diagnostic phase surface based on state variables acquired at the time of diagnosis; calculating the total displacement of the judgment phase surface relative to the judgment phase surface; and comparing the total displacement with a preset displacement judgment value to determine whether or not an abnormality exists. By comparing the total displacement of the diagnostic phase surface data with the displacement judgment value relative to the judgment phase surface data to determine an abnormality, it is possible to detect outward and inward displacements of the diagnostic phase surface data relative to the judgment phase surface data and determine the abnormality. As a result, highly accurate diagnosis can be achieved by monitoring the state variables of the drive system.

In the above-described embodiment, the phase plane data calculation unit 44 and the abnormality determination unit 45 processed the first phase plane data and the second phase plane data, but this is not limited to two phase plane data. The number of phase plane data to be processed may be one or three or more. Furthermore, while angular velocity ω, current i, and voltage u were used as state variables, this configuration is not limited to this.

Furthermore, in addition to the above, control deviation and current data for each phase of a three-phase motor can also be used as state variables. If there is an abnormality in the control system, the deviation will change, and if the current of each phase decreases or increases below normal, this can be detected as a change on the phase plane. By expressing this phase plane shift and the abnormality as a function, it is possible to handle more detailed abnormality classification.

10 Drive system 11 Motor 12 Rotating shaft 13 Load 14 Case 21 Motor amplifier 22 Motor control unit 23 Angular velocity sensor 24 Current sensor 25 Voltage sensor 30 Status monitoring device 31 Status monitoring control unit 32 Operation unit 33 Display unit 34 Storage unit 41 Data acquisition unit 42 Phase plane data creation unit for determination 43 Phase plane data creation unit for diagnosis 44 Phase plane data calculation unit 45 Anomaly determination unit 50 Diagnostic device 51 Diagnostic control unit

Claims (11)

A data acquisition unit that acquires state variables,
A determination phase plane data creation unit that creates determination phase plane data based on the state variables under normal conditions,
A diagnostic phase plane data creation unit that creates diagnostic phase plane data based on state quantities acquired during diagnosis,
A phase surface data calculation unit calculates the total displacement amount of the diagnostic phase surface data relative to the determination phase surface data,
An output unit that outputs the total displacement amount,
Equipped with,
The total displacement is the displacement of the centroid of the diagnostic phase plane data relative to the centroid of the determination phase plane data.
Condition monitoring device. A data acquisition unit that acquires state variables,
A determination phase plane data creation unit that creates determination phase plane data based on the state variables under normal conditions,
A diagnostic phase plane data creation unit that creates diagnostic phase plane data based on state quantities acquired during diagnosis,
A phase surface data calculation unit calculates the total displacement amount of the diagnostic phase surface data relative to the determination phase surface data,
An output unit that outputs the total displacement amount,
Equipped with,
The data acquisition unit acquires the motor's angular velocity, current, and voltage as state variables, and the determination phase plane data creation unit and the diagnostic phase plane data creation unit create at least one of the following: a first phase plane data of the current relative to the angular velocity and a second phase plane data of the voltage relative to the angular velocity.
Condition monitoring device. The phase plane data calculation unit calculates the total first displacement amount of the diagnostic first phase plane data relative to the determination first phase plane data, and calculates the total second displacement amount of the diagnostic second phase plane data relative to the determination second phase plane data, and the output unit outputs the total first displacement amount and the total second displacement amount.
The status monitoring device according to claim 2 . The total displacement is the displacement of multiple fixed points set in the diagnostic phase surface data relative to multiple fixed points set in the determination phase surface data.
A condition monitoring device according to claim 2 or claim 3 . The determination phase plane data creation unit uses previously created phase plane data or average phase plane data obtained by averaging multiple previously created phase plane data as the determination phase plane data.
A condition monitoring device according to any one of claims 1 to 4 . The determination phase plane data creation unit uses the maximum phase plane data or minimum phase plane data created in the past as the determination phase plane data.
A condition monitoring device according to any one of claims 1 to 4 . The output unit has a display unit that displays the total displacement amount by superimposing the determination phase plane data and the diagnostic phase plane data.
A condition monitoring device according to any one of claims 1 to 6 . A condition monitoring device according to any one of claims 1 to 7 ,
An abnormality determination unit that compares the total displacement amount with a preset displacement amount determination value to determine whether or not it is abnormal,
A diagnostic device that has [a certain feature]. The abnormality determination unit determines that an abnormality exists if the total displacement exceeds the displacement determination value.
The diagnostic device according to claim 8 . The process of acquiring state variables,
A process to create a phase plane for determination based on the state variables under normal conditions,
A process of creating a diagnostic phase surface based on state quantities obtained during diagnosis,
A step of calculating the total displacement of the diagnostic phase surface with respect to the determination phase surface,
A step of outputting the total displacement amount,
It has,
The total displacement is the displacement of the centroid of the diagnostic phase surface relative to the centroid of the determination phase surface.
Status monitoring method. The process of acquiring state variables,
A process to create a phase plane for determination based on the state variables under normal conditions,
A process of creating a diagnostic phase surface based on state quantities obtained during diagnosis,
A step of calculating the total displacement of the diagnostic phase surface with respect to the determination phase surface,
A step of comparing the total displacement amount with a predetermined displacement amount determination value to determine whether or not it is abnormal,
It has,
The total displacement is the displacement of the centroid of the diagnostic phase surface relative to the centroid of the determination phase surface.
Diagnostic methods.