Diagnostic device, motor control device, diagnostic method, diagnostic program

Abstract

To provide a diagnosis device, etc. capable of properly detecting a non-continuous abnormality.SOLUTION: A diagnosis device 30 includes a normality frequency acquisition unit 311 that acquires a normality frequency with which a data acquisition unit 12 connected to a detector 21 has normally acquired detection data obtained by the detector 21, an abnormality frequency acquisition unit 312 that acquires an abnormality frequency with which the data acquisition unit 12 has failed to normally acquire detection data obtained by the detector 21, and an abnormality determination unit 32 that determines an abnormality if the difference between the abnormality frequency and the normality frequency is greater than an abnormality determination threshold. The normality frequency acquisition unit 311 and the abnormality frequency acquisition unit 312 are formed of a counter 31 that is incremented to one direction indicating an abnormality frequency if the data acquisition unit 12 fails to normally acquire the detection data, and is incremented to the other direction indicating a normality frequency if the data acquisition unit 12 normally acquires the detection data.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a diagnostic device and the like.

Background Art

[0002] Patent Document 1 discloses a motor drive device including a data acquisition unit that acquires the rotational position of a motor detected by a position detector such as an encoder. In order to determine a communication abnormality between the position detector and the data acquisition unit, a single-occurrence threshold value for determining a single (single-shot) communication abnormality and a continuous threshold value for determining a continuous communication abnormality over a plurality of times are provided.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the determination using the continuous threshold value, since it is necessary for the communication abnormality to continue over a plurality of times, there is a risk of overlooking communication abnormalities that occur discontinuously, intermittently, or intermittently.

[0005] The present invention has been made in view of such a situation, and an object thereof is to provide a diagnostic device or the like that can appropriately detect discontinuous abnormalities.

Means for Solving the Problems

[0006] In order to solve the above problems, a diagnostic device according to an aspect of the present invention includes a normal frequency acquisition unit that acquires the normal frequency at which the data acquisition unit connected to the detector can normally acquire the detection data detected by the detector, an abnormal frequency acquisition unit that acquires the abnormal frequency at which the data acquisition unit cannot normally acquire the detection data detected by the detector, and an abnormality determination unit that determines an abnormality based on the abnormal frequency and the normal frequency.

[0007] In this embodiment, an anomaly is determined based on the frequency of anomalies in which the data acquisition unit failed to acquire detection data properly, and the frequency of normal occurrences in which the data acquisition unit successfully acquired detection data. Discrete anomalies are also appropriately considered as part of the anomaly frequency.

[0008] Another aspect of the present invention is a motor control device. This device is a motor control device for controlling a motor and comprises: a data acquisition unit connected to a detector and acquiring detection data detected by the detector; a motor drive unit that drives the motor based on the detection data acquired by the data acquisition unit; a normal frequency acquisition unit that acquires the normal frequency at which the data acquisition unit was able to acquire the detection data detected by the detector; an abnormal frequency acquisition unit that acquires the abnormal frequency at which the data acquisition unit was unable to acquire the detection data detected by the detector; and an abnormality determination unit that determines an abnormality based on the abnormal frequency and the normal frequency.

[0009] Another aspect of the present invention is a diagnostic method. This method comprises: a normal frequency acquisition step of acquiring the normal frequency at which a data acquisition unit connected to the detector was able to successfully acquire detection data detected by the detector; an abnormal frequency acquisition step of acquiring the abnormal frequency at which the data acquisition unit was unable to successfully acquire detection data detected by the detector; and an abnormality determination step of determining an abnormality based on the abnormal frequency and the normal frequency.

[0010] Furthermore, any combination of the above components, as well as methods, apparatus, systems, recording media, computer programs, etc., derived from these representations, are also included in the present invention. [Effects of the Invention]

[0011] According to the present invention, discontinuous anomalies can be appropriately detected. [Brief explanation of the drawing]

[0012] [Figure 1] The configuration of the motor control device is schematically shown. [Figure 2]An example of abnormality detection by a counter and abnormality detection unit is shown. [Figure 3] This flowchart shows an example of processing performed by a diagnostic device. [Modes for carrying out the invention]

[0013] The following describes in detail the embodiments (hereinafter also referred to as "models") for carrying out the present invention, with reference to the drawings. In the description and / or drawings, identical or equivalent components, members, processes, etc., are denoted by the same reference numerals, and redundant descriptions are omitted. The scale and shape of the illustrated parts are set for convenience to simplify the description and are not to be interpreted restrictively unless otherwise specified. The embodiments are illustrative and do not limit the scope of the present invention in any way. Not all features or combinations thereof described in the embodiments are necessarily essential to the present invention.

[0014] Figure 1 schematically shows the configuration of a motor control device 10 which may include a diagnostic device 30 according to this embodiment. The motor control device 10 is responsible for controlling and / or driving the motor 20 that generates rotational power. The coils, etc. of the stator (not shown) of the motor 20 generate a rotating magnetic field based on the DC or AC drive current applied from the motor drive unit 11 in the motor control device 10. The permanent magnets, coils, etc. of the rotor (not shown) of the motor 20 receive magnetic force from the rotating magnetic field generated by the stator. As a result, the rotor of the motor 20 is rotationally driven relative to the stator, and rotational power is generated.

[0015] The motor 20 is equipped with a detector 21, such as a rotary encoder or a magnetic sensor like a Hall element, which can detect the rotational position (rotation angle) and rotational speed of the rotor. The motor 20 may also be configured as a linear motor. In this case, the detector 21 may be configured as a linear encoder or the like, which can detect the translational position and translational speed of a movable element that can move linearly relative to the stator of the motor 20 (typically forming a linear track).

[0016] The data acquisition unit 12 in the motor control device 10 is communicated with the detector 21 in the motor 20 by wire or wireless means. The data acquisition unit 12 receives detection data of the motor 20's drive position (rotational position of the rotor and translational position of the linear movable element) and drive speed (rotational speed of the rotor and translational speed of the linear movable element) detected and transmitted by the detector 21. The detection data from the detector 21 that is successfully received (acquired) by the data acquisition unit 12 is provided to the motor drive unit 11. As a result, the motor drive unit 11 can apply an appropriate drive current to the stator of the motor 20 to control or maintain the rotor and movable element of the motor 20 in a desired drive state, according to the drive position and drive speed of the motor 20 detected by the detector 21.

[0017] For the data acquisition unit 12 to successfully receive detection data from the detector 21, the detector 21 must be functioning correctly, and communication between the detector 21 and the data acquisition unit 12 must be functioning normally. The diagnostic device 30 according to this embodiment, which will be described in detail below, can effectively detect malfunctions in the detector 21 and communication abnormalities between the detector 21 and the data acquisition unit 12 (i.e., communication abnormalities between the detector 21 and the motor control device 10).

[0018] The diagnostic device 30 includes a counter 31 and an abnormality determination unit 32. These functional blocks may be realized through the cooperation of hardware resources such as the central processing unit, memory, input devices, output devices, and peripheral devices connected to the computer, and software executed using them. Regardless of the type or location of the computer, each of the above functional blocks may be realized using the hardware resources of a single computer, or by combining hardware resources distributed across multiple computers. In this embodiment, the entire diagnostic device 30 is included in the motor control device 10, but all or part of the components of the diagnostic device 30 may be provided outside the motor control device 10.

[0019] The counter 31 is an implementation example for realizing the normal frequency acquisition unit 311 and the abnormal frequency acquisition unit 312. Therefore, as long as part or all of the functions of the normal frequency acquisition unit 311 and the abnormal frequency acquisition unit 312 described below are realized, these implementation modes are not limited to the counter 31.

[0020] The normal frequency acquisition unit 311 acquires the detection data of the motor 20 detected by the detector 21 as the normal frequency that the data acquisition unit 12 has successfully acquired. Here, the normal frequency is any form of information correlated with the ratio of the number of normal acquisitions to the total number of data acquisitions in an arbitrary period that includes at least a plurality of data acquisitions (data reception from the detector 21) by the data acquisition unit 12. For example, in a period when the data acquisition by the data acquisition unit 12 includes "100 times", if "75 times" of them are normal acquisitions, the ratio "75%" itself may be acquired as the normal frequency.

[0021] The abnormal frequency acquisition unit 312 acquires the detection data of the motor 20 detected by the detector 21 as the abnormal frequency that the data acquisition unit 12 has failed to acquire normally. Here, the abnormal frequency is any form of information correlated with the ratio of the number of abnormal acquisitions (or the number of normal acquisition failures) to the total number of data acquisitions in a period substantially equivalent to the period in which the normal frequency acquisition unit 311 described above acquires the normal frequency (there may be some deviation). For example, in a period when the data acquisition by the data acquisition unit 12 includes "100 times", if "25 times" of them are abnormal acquisitions, the ratio "25%" itself may be acquired as the abnormal frequency.

[0022] When the normal frequency acquisition unit 311 and the abnormal frequency acquisition unit 312 are implemented by a counter 31, if the data acquisition unit 12 fails to acquire detection data from the detector 21 normally, the counter 31 counts up in one direction (hereinafter referred to as the positive direction, but it may also be the negative direction) that represents the abnormal frequency of the abnormal frequency acquisition unit 312, and if the data acquisition unit 12 successfully acquires detection data from the detector 21 normally, the counter 31 counts down in the opposite direction (hereinafter referred to as the negative direction, but it may also be the positive direction) that represents the normal frequency of the normal frequency acquisition unit 311. In other words, the counter 31 counts up by "+1" each time an abnormal acquisition occurs in the data acquisition unit 12, and counts down by "-1" each time a normal acquisition occurs in the data acquisition unit 12. Note that the amount of counting up when an abnormal acquisition occurs and the amount of counting down when a normal acquisition occurs may be different from each other. In particular, by making the count-up amount when an anomaly is detected larger than the count-down amount when a normal detection occurs (for example, by setting the count-up amount to "+2" and the count-down amount to "-1"), it becomes possible to "weight" the detection of an anomaly, thereby increasing the sensitivity of the anomaly detection unit 32, which will be described later.

[0023] The abnormality determination unit 32 determines an abnormality (such as an operational abnormality of the detector 21 or a communication abnormality between the detector 21 and the data acquisition unit 12) if the difference between the abnormality frequency acquired by the abnormality frequency acquisition unit 312 and the normality frequency acquired by the normality frequency acquisition unit 311 is greater than a predetermined abnormality determination threshold. For example, the abnormality determination unit 32 determines an abnormality if the difference between the abnormality frequency "60%" acquired by the abnormality frequency acquisition unit 312 over a predetermined period and the normality frequency "40%" acquired by the normality frequency acquisition unit 311 over a predetermined period is "20%" and this difference is greater than a predetermined abnormality determination threshold of "10%". Note that the abnormality determination unit 32 can determine an abnormality not only when the abnormality frequency is higher than the normal frequency, but also when the abnormality frequency is lower than the normal frequency. For example, if the abnormality detection threshold is set to "-30%", the abnormality detection unit 32 will determine an abnormality if the difference between the abnormality frequency "40%" acquired by the abnormality frequency acquisition unit 312 over a predetermined period and the normality frequency "60%" acquired by the normality frequency acquisition unit 311 over a predetermined period, which is "-20%", is greater than the predetermined abnormality detection threshold "-30%".

[0024] When the normal frequency acquisition unit 311 and the abnormal frequency acquisition unit 312 are implemented by the counter 31, the abnormality determination unit 32 determines an abnormality when the count value of the counter 31 exceeds the abnormality determination threshold in the positive direction (one direction). The abnormality determination threshold for the count value of the counter 31 may be any value of positive, zero, or negative, but in the following example, it is set to "10". Also, the counter 31 has an upper limit (one limit) of the count value in the positive direction (one direction) from the abnormality determination threshold "10" and a lower limit (the other limit) of the count value in the negative direction (the other direction) from the abnormality determination threshold "10".

[0025] The upper limit of the count value may be any value greater than the abnormality determination threshold (10), but it is preferably between 1.5 times (15) and 3 times (30) of the abnormality determination threshold, and more preferably between 1.5 times (15) and 2.5 times (25) of the abnormality determination threshold. In the following example, the upper limit of the count value is set to "20", which is 2 times the abnormality determination threshold. The lower limit of the count value may be any value (positive / zero / negative) smaller than the abnormality determination threshold (10), but in the following example, it is set to "0" only for the purpose of simplifying the explanation.

[0026] When the upper limit "20" and the lower limit "0" are set for the counter 31 in this way, the count value of the counter 31 is restricted between "0" and "20". For example, when the count value of the counter 31 is the lower limit "0", even if normal acquisition occurs in the data acquisition unit 12 that would normally involve a count - down of "-1", the counter 31 does not count down and the count value is maintained at "0". On the other hand, when abnormal acquisition occurs in the data acquisition unit 12 in this state, the counter 31 counts up by "+1" as normal and the count value is updated to "1". Similarly, when the count value of the counter 31 is the upper limit "20", even if abnormal acquisition occurs in the data acquisition unit 12 that would normally involve a count - up of "+1", the counter 31 does not count up and the count value is maintained at "20". On the other hand, when normal acquisition occurs in the data acquisition unit 12 in this state, the counter 31 counts down by "-1" as normal and the count value is updated to "19".

[0027] Figure 2 shows an example of abnormality detection by the counter 31 and the abnormality detection unit 32. Figure 2A schematically shows normal acquisition and abnormal acquisition in the data acquisition unit 12 using binary values. Figure 2B schematically shows the count value of the counter 31. When a normal acquisition occurs, indicated as "Normal" in Figure 2A, the count value of the counter 31 in Figure 2B counts down by "-1" (if the count value was at the lower limit of "0", it is maintained at "0"). Also, when an abnormal acquisition occurs, indicated as "Abnormal" in Figure 2A, the count value of the counter 31 in Figure 2B counts up by "+1" (if the count value was at the upper limit of "20" which is not shown, it is maintained at "20").

[0028] In the example shown in Figure 2A, as time progresses from left to right, abnormal data acquisition becomes dominant over normal data acquisition. In other words, the abnormal frequency acquired by the abnormal frequency acquisition unit 312 remains higher than the normal frequency acquired by the normal frequency acquisition unit 311. When abnormal data acquisition, caused by malfunctions in the detector 21 or communication errors between the detector 21 and the data acquisition unit 12, continues to be dominant, the count value of the counter 31 gradually accumulates in the positive direction, as shown in Figure 2B, resulting in it exceeding the abnormality detection threshold "10" in the positive direction (i.e., becoming "11" or higher). Upon receiving this, the abnormality detection unit 32 can accurately determine the abnormality at the point indicated as "abnormality detected" in Figure 2B.

[0029] The dotted line in Figure 2B represents a comparative example when the continuous threshold disclosed in Patent Document 1 is applied. Since the continuous threshold only considers continuous abnormal acquisitions, if normal acquisitions occur discontinuously, intermittently, or intermittently as in Figure 2A, the counter 31 is "reset" to "0". As a result, even if abnormal acquisitions are dominant, the count value of the counter 31 may not exceed the abnormality detection threshold of "10", and there is a risk that abnormalities will be overlooked.

[0030] As described above, the diagnostic device 30 according to this embodiment can accurately determine abnormalities based on the difference between the frequency of abnormalities in which detection data was not properly acquired by the data acquisition unit 12 and the frequency of normalities in which detection data was properly acquired by the data acquisition unit 12. Discrete abnormalities, which may have been overlooked in Patent Document 1, are also appropriately considered as abnormalities acquired by the abnormality frequency acquisition unit 312.

[0031] Furthermore, by setting an upper limit such as "20" and / or a lower limit such as "0" for the count value of the counter 31, excessive accumulation or buildup of abnormal and / or normal acquisitions in the data acquisition unit 12 is prevented. For example, when the motor control device 10 and motor 20 are operating normally, it is expected that normal acquisitions accompanied by a countdown of the counter 31's count value will continue at a very high frequency. In such a case, if a lower limit such as "0" is not set for the counter 31's count value, the absolute value of the count value will increase indefinitely in the negative direction. Also, even if abnormal acquisitions become dominant from this state, it will take an enormous amount of time for the counter 31's count value to count up to the abnormality detection threshold of "10". Therefore, by setting a lower limit such as "0", the counter 31's count value will remain at "0" during normal operation, and when an abnormality occurs, it will quickly count up to the abnormality detection threshold of "10".

[0032] Similarly, if an abnormality occurs in the motor control device 10 and / or the motor 20, it is likely that abnormal acquisitions accompanied by an increment in the counter 31's count value will continue at an extremely high frequency. In such cases, if an upper limit such as "20" is not set for the counter 31's count value, the absolute value of the count value will increase indefinitely in the positive direction. Furthermore, even if the abnormality is resolved and normal acquisition becomes dominant, it will take an enormous amount of time for the counter 31's count value to count down to the normal value (lower limit) of "0". Therefore, by setting an upper limit such as "20", the counter 31's count value will stick to "20" during abnormal operation, and can quickly count down to the normal value of "0" when the abnormality is resolved.

[0033] Figure 3 is a flowchart showing an example of processing by the diagnostic device 30 according to this embodiment. In the flowchart, "S" represents a step or process. In S1, the data acquisition unit 12 determines whether or not an abnormal acquisition has occurred. If "Yes" is determined in S1, the process proceeds to S2, where it is determined whether or not the count value of the counter 31 is at its upper limit (e.g., "20"). If "No" is determined in S2, the process proceeds to S3, where the count value of the counter 31 is incremented according to the abnormal acquisition determined in S1. In the following S4, it is determined whether or not the count value of the counter 31 is greater than the abnormality determination threshold (e.g., "10"). If "Yes" is determined in S4, the process proceeds to S5, where the abnormality determination unit 32 determines an abnormality, assuming that the count value of the counter 31 has exceeded the abnormality determination threshold due to the abnormal acquisition determined in S1. If "No" is determined in S4, the process returns to S1.

[0034] If "Yes" is determined in S2, proceed to S6, and counter 31 will not count up, maintaining its count at the upper limit. Then return to S1. If "No" is determined in S1, proceed to S7, where it is determined whether the count of counter 31 is at the lower limit (for example, "0"). If "No" is determined in S7, proceed to S8, and the count of counter 31 will count down according to the successful acquisition determined in S1. Then return to S1. If "Yes" is determined in S7, proceed to S6, and counter 31 will not count down, maintaining its count at the lower limit. Then return to S1.

[0035] The present invention has been described above based on embodiments. Various modifications are possible for each component and each combination of processes in the exemplary embodiments, and it will be obvious to those skilled in the art that such modifications are included within the scope of the present invention.

[0036] The configuration, operation, and function of each device and method described in the embodiments can be realized by hardware resources or software resources, or by the cooperation of hardware resources and software resources. Hardware resources include, for example, processors, ROMs, RAMs, and various integrated circuits. Software resources include, for example, operating systems and application programs. [Explanation of symbols]

[0037] 10 Motor control device, 11 Motor drive unit, 12 Data acquisition unit, 20 Motor, 21 Detector, 30 Diagnostic device, 31 Counter, 32 Anomaly determination unit, 311 Normal frequency acquisition unit, 312 Anomaly frequency acquisition unit.

Claims

1. A normal frequency acquisition unit acquires the normal frequency at which the detection data detected by the detector was successfully acquired by the data acquisition unit connected to the detector, The detection data detected by the detector is acquired by an abnormal frequency acquisition unit that acquires the abnormal frequency at which the data acquisition unit could not acquire the data normally, An abnormality determination unit based on the abnormality frequency and the normal frequency, Equipped with, The abnormality determination unit determines an abnormality when the difference between the abnormality frequency and the normal frequency is greater than the abnormality determination threshold. The normal frequency acquisition unit and the abnormal frequency acquisition unit are each composed of a counter that counts in one direction representing the abnormal frequency when the data acquisition unit fails to acquire the detection data normally, and counts in the other direction opposite to the one direction representing the normal frequency when the data acquisition unit successfully acquires the detection data normally. The abnormality determination unit determines an abnormality when the count value of the counter exceeds the abnormality determination threshold in one direction. The counter has one limit to its count value in one direction above the abnormality detection threshold, and if the data acquisition unit fails to acquire the detection data normally when the count value is at that limit, the count value is maintained at that limit. Diagnostic equipment.

2. The diagnostic device according to claim 1, wherein the counter has a limit to the count value in the other direction, and when the count value is at the limit to the other direction, if the data acquisition unit is able to successfully acquire the detection data, the count value is maintained at the limit to the other direction.

3. The diagnostic device according to claim 1 or 2, wherein the detector detects the rotational position of the motor as the detection data.

4. A motor control device that controls a motor, A data acquisition unit connected to a detector and which acquires detection data detected by the detector, A motor drive unit drives the motor based on the detection data acquired by the data acquisition unit, The detection data detected by the detector is acquired by a normal frequency acquisition unit that acquires the normal frequency that the data acquisition unit was able to acquire successfully, The detection data detected by the detector is acquired by an abnormal frequency acquisition unit that acquires the abnormal frequency at which the data acquisition unit could not acquire the data normally, An abnormality determination unit based on the abnormality frequency and the normal frequency, Equipped with, The abnormality determination unit determines an abnormality when the difference between the abnormality frequency and the normal frequency is greater than the abnormality determination threshold. The normal frequency acquisition unit and the abnormal frequency acquisition unit are each composed of a counter that counts in one direction representing the abnormal frequency when the data acquisition unit fails to acquire the detection data normally, and counts in the other direction opposite to the one direction representing the normal frequency when the data acquisition unit successfully acquires the detection data normally. The abnormality determination unit determines an abnormality when the count value of the counter exceeds the abnormality determination threshold in one direction. The counter has one limit to its count value in one direction above the abnormality detection threshold, and if the data acquisition unit fails to acquire the detection data normally when the count value is at that limit, the count value is maintained at that limit. Motor control device.

5. A normal frequency acquisition step involves acquiring the normal frequency at which the detection data detected by the detector was successfully acquired by the data acquisition unit connected to the detector, and The detection data detected by the detector is used in an abnormal frequency acquisition step to acquire the abnormal frequency at which the data acquisition unit failed to acquire the data correctly. An abnormality determination step that determines an abnormality based on the abnormality frequency and the normal frequency, Equipped with, The abnormality determination step determines an abnormality if the difference between the abnormality frequency and the normal frequency is greater than the abnormality determination threshold. The normal frequency acquisition step and the abnormal frequency acquisition step are performed by a counter that counts in one direction representing the abnormal frequency when the data acquisition unit fails to acquire the detection data normally, and counts in the other direction opposite to the one direction representing the normal frequency when the data acquisition unit succeeds in acquiring the detection data normally. The abnormality determination step determines an abnormality when the count value of the counter exceeds the abnormality determination threshold in one direction. The counter has one limit to its count value in one direction above the abnormality detection threshold, and if the data acquisition unit fails to acquire the detection data normally when the count value is at that limit, the count value is maintained at that limit. Diagnostic methods.

6. A normal frequency acquisition step involves acquiring the normal frequency at which the detection data detected by the detector was successfully acquired by the data acquisition unit connected to the detector, and The detection data detected by the detector is used in an abnormal frequency acquisition step to acquire the abnormal frequency at which the data acquisition unit failed to acquire the data correctly. An abnormality determination step that determines an abnormality based on the abnormality frequency and the normal frequency, Have the computer run it, The abnormality determination step determines an abnormality if the difference between the abnormality frequency and the normal frequency is greater than the abnormality determination threshold. The normal frequency acquisition step and the abnormal frequency acquisition step are performed by a counter that counts in one direction representing the abnormal frequency when the data acquisition unit fails to acquire the detection data normally, and counts in the other direction opposite to the one direction representing the normal frequency when the data acquisition unit succeeds in acquiring the detection data normally. The abnormality determination step determines an abnormality when the count value of the counter exceeds the abnormality determination threshold in one direction. The counter has one limit to its count value in one direction above the abnormality detection threshold, and if the data acquisition unit fails to acquire the detection data normally when the count value is at that limit, the count value is maintained at that limit. Diagnostic program.

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