Brushed motor rotation speed detection device, brushed motor control device, drive device, and method for measuring brushed motor rotation speed

Abstract

To make it possible to detect rotation speed of a brushed motor with a simple configuration.SOLUTION: A motor rotation speed detection device 14 includes: a measurement unit 22 that measures a value of a current flowing through a motor 80; a storage unit 26 that stores temporal change data that is temporal change in the current value measured by the measurement unit 22; a calculation unit 30 that calculates moving average data in a predetermined time unit from the temporal change data; an addition unit 32 that calculates threshold data by adding a predetermined deviation amount B to the moving average data; and a derivation unit 40 that derives rotation speed of the motor 80 based on time when a value of the temporal change data becomes larger than a value of the threshold data.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a brushed motor rotation speed detection device, a brushed motor control device, a drive device, and a brushed motor rotation speed measurement method. [Background technology]

[0002] For example, Patent Document 1 discloses a control device for a brushless DC motor that drives and rotates a brushless DC motor having a rotor with a permanent magnet and a stator with a multi-phase stator winding that generates a rotating magnetic field that rotates the rotor, using a current switching means that consists of multiple switching elements and sequentially commutates the current to the stator winding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-252995 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to enable detection of the rotation speed of a brushed motor with a simple configuration. [Means for solving the problem]

[0005] The brushed motor rotation speed detection device disclosed herein comprises a measurement unit that measures the value of the current flowing through the brushed motor, a memory unit that stores time-varying data, which is the change over time in the current value measured by the measurement unit, a calculation unit that calculates moving average data from the time-varying data in predetermined time units, an addition unit that calculates threshold data by adding a predetermined deviation amount to the moving average data, and a derivation unit that derives the rotation speed of the brushed motor based on the time when the value of the time-varying data becomes greater than the value of the threshold data.

[0006] This brushed motor rotation speed detection device derives the rotation speed of the brushed motor based on threshold data obtained by sequentially calculating from time-varying data obtained by measuring the value of the current flowing through the brushed motor. In other words, the brushed motor rotation speed detection device of this aspect calculates the rotation speed of the brushed motor from the value of the current flowing through the brushed motor, making it possible to detect the rotation speed of a brushed motor without a Hall IC. As a result, the brushed motor rotation speed detection device of this aspect makes it possible to detect the rotation speed of a brushed motor with a simple configuration. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to detect the rotation speed of a brushed motor with a simple configuration. [Brief explanation of the drawings]

[0008] [Figure 1] 1A and 1B are diagrams illustrating a drive device according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a diagram showing a current waveform when a brushed motor in a drive device according to an embodiment of the present disclosure starts to rotate. [Figure 3] FIG. 3 is a diagram showing a state in which moving average data is calculated from the current waveform of FIG. 2. [Figure 4] 4 is a diagram showing a state in which threshold data is calculated by adding a deviation amount to the value indicated by the moving average data of FIG. 3. FIG. [Figure 5] 5 is a diagram showing how pulse data is calculated based on the time when the current waveform shown in FIG. 1 exceeds the threshold data shown in FIG. 4. FIG. [Figure 6] FIG. 10 is a diagram showing moving average data according to the embodiment, illustrating how the number of samples is changed depending on the current value. [Figure 7] FIG. 10 is a diagram showing threshold data according to the embodiment, illustrating a state in which ripples are reduced as the rotation of the brushed motor becomes stable. [Figure 8] FIG. 8 is a diagram showing the threshold data of FIG. 7, illustrating how the deviation amount is changed. DETAILED DESCRIPTION OF THE INVENTION

[0009] An example of an embodiment of the present disclosure will be described below with reference to the drawings. In each drawing, the same or equivalent components and parts are designated by the same reference numerals. Furthermore, the dimensional proportions in the drawings are exaggerated for the sake of explanation and may differ from the actual proportions.

[0010] In the following description, a brushed motor will be referred to simply as a "motor" and will be described on the assumption that it is a brushed motor. The rotation speed of a brushed motor will also be referred to simply as the "motor rotation speed," and the same applies to other terms.

[0011] [Embodiment] (composition) 1 is a diagram illustrating a drive device 10 according to an embodiment of the present disclosure. As shown in FIG. 1, the drive device 10 includes a control device 12 and a motor 80.

[0012] 1, the motor 80 is electrically connected to a DC power supply 84. The motor 80 has brushes 82 on the hot side and the ground side, and each brush 82 slides while electrically connected to a commutator 86 on the rotor of the motor 80, thereby rotating the rotor relative to the stator.

[0013] 1, an object to be moved 90 is mechanically connected to the motor 80, and the object to be moved 90 is moved by driving the motor 80. The object to be moved 90 may be any object, and for example, when the drive device 10 is installed in an automobile, the object to be moved 90 may be a side window glass of a power window, a wiper blade, etc.

[0014] 1, a shunt resistor 24 is provided in series between the motor 80 and the DC power supply 84. Both terminals of the shunt resistor 24 are connected to a measuring unit 22, which will be described later.

[0015] As shown in FIG. 1, the control device 12 includes a control unit 34 and a motor rotation speed detection device 14.

[0016] The motor rotation speed detection device 14 includes a processor 20, a measurement unit 22, a storage unit 26, and a recording unit 28. These components are connected by a bus (not shown).

[0017] The processor 20 is, for example, a CPU, which reads a program 42 from a recording unit 28 (described later) and operates to function as a calculation unit 30, an addition unit 32, and a derivation unit 40, as shown in FIG.

[0018] In a procedure for detecting the motor rotation speed, which will be described later, the calculation unit 30 calculates moving average data from the time-varying data in predetermined time units. In a procedure for detecting the motor rotation speed, which will be described later, the addition unit 32 adds a predetermined deviation amount B to the moving average data to calculate threshold data. In a procedure for detecting the motor rotation speed, which will be described later, the derivation unit 40 derives the rotation speed of the motor 80 based on the time when the value of the time-varying data becomes greater than the value of the threshold data. The specific functions of these components will be described in the procedure for detecting the motor rotation speed, which will be described later.

[0019] The storage unit 26 is, for example, a volatile memory such as a RAM (Random Access Memory), and temporarily stores a program 42 executed by the processor 20 and various data described later.

[0020] The recording unit 28 is, for example, a non-volatile memory such as a ROM (Read Only Memory), and as shown in Fig. 1, a program 42 to be read by the processor 20 is recorded in the recording unit 28. As shown in Fig. 1, in this embodiment, the recording unit 28 also records, as data, the values ​​of a time setting value 44, a deviation amount setting value 46, a current setting value 48, and a pulse ratio setting value 50. The time setting value 44, the deviation amount setting value 46, the current setting value 48, and the pulse ratio setting value 50 will be explained in the procedure for detecting the motor rotation speed, which will be described later.

[0021] The measuring unit 22 is connected to the shunt resistor 24 and measures the magnitude of the current flowing through the motor 80. The measured current value is temporarily stored in the storage unit 26 as time-varying data.

[0022] 1, the control unit 34 communicates with the motor rotation speed detection device 14 and the DC power supply 84. More specifically, the control unit 34 communicates with the motor rotation speed detection device 14, and controls the DC power supply 84 based on the result derived by the derivation unit 40. The control unit 34 also controls the voltage of the DC power supply 84, thereby controlling the rotation speed of the motor 80. Note that any method may be used as the method for controlling the DC voltage by the control unit 34, but a pulse width modulation method is used as an example.

[0023] (Current waveform flowing through the motor) When the control unit 34 controls the DC power supply 84 to apply a DC voltage to the motor 80, the rotor of the motor 80 begins to rotate. At this time, the current flowing through the shunt resistor 24, i.e., the current flowing through the motor 80, is large initially, as shown in FIG. 2, but as the rotation speed increases over time, the measured current value decreases.

[0024] In a motor 80 with brushes 82, the rotor's commutator 86 rotates while in contact with the brushes 82, so the rotation angle of the rotor changes and the commutator 86 in contact with the brushes 82 changes. When the commutator 86 in contact with the brushes 82 changes, an induced electromotive force is generated by the armature reaction, and a ripple (pulsating component) appears in the measured current waveform, as shown in Figure 2.

[0025] Next, the control procedure of the drive device 10 according to this embodiment will be described with reference to Fig. 2 and Fig. 3 to Fig. 5. In this embodiment, the control procedure of the drive device 10 includes a procedure for detecting the motor rotation speed and a procedure for controlling the motor rotation speed.

[0026] (Procedure for detecting motor rotation speed) The driving device 10 in this embodiment executes the following various procedures by the processor 20 in the control device 12 executing the program 42 read from the recording unit 28.

[0027] First, the processor 20 acquires the value of the current flowing through the shunt resistor 24 over time from the measuring unit 22, and causes the control unit 34 to start the DC power supply 84 and start driving the motor 80. Then, the processor 20 temporarily stores the current value acquired from the measuring unit 22 in the memory unit 26 as time-varying data, and acquires a current waveform as shown by the solid line in FIG.

[0028] Next, the processor 20, as the calculation unit 30, calculates the average current value for each predetermined time unit for the current waveform shown in Fig. 2. More specifically, the processor 20 calculates the average value for multiple sampling data going back from a specific time point in the time-varying data to a predetermined time unit. The calculated average value is then set as the average value for the specific time point. By repeating this process, moving average data such as that shown by the dashed line in Fig. 3 is calculated.

[0029] For example, Fig. 3 shows an example in which the average of five points D1 to D5 of the time-varying data is set as the value of moving average data point M1, and the average of five points D2 to D6 is set as the value of moving average data point M2. In the example in Fig. 3, the predetermined time unit is a time period equivalent to five points (sampling time). However, the predetermined time unit is not limited to five points.

[0030] In this embodiment, the predetermined time unit is the time setting value 44 recorded in the recording unit 28. In other words, the processor 20 determines the sampling time for calculating the average value of the current value based on the time setting value 44 read from the recording unit 28, and creates moving average data as the calculation unit 30.

[0031] Next, processor 20, functioning as adder 32, adds deviation amount B to each data point of the moving average data, as shown in FIG. 4. More specifically, processor 20 adds a predetermined deviation amount B to each data point of the moving average data. The calculated value is then set as the threshold value for a specific period. By repeating this process, threshold data such as that shown by the dashed line in FIG. 4 is calculated.

[0032] For example, FIG. 4 shows an example in which a deviation amount B is added to a specific value of the moving average data to set the threshold value T1.

[0033] In this embodiment, the predetermined deviation amount B is the deviation amount setting value 46 recorded in the recording unit 28. In other words, the processor 20 determines the deviation amount B based on the deviation amount setting value 46 read from the recording unit 28, and creates threshold data as the adding unit 32.

[0034] Next, as shown in Fig. 5, processor 20, as derivation unit 40, compares the magnitude relationship between the time-varying data and each time period for each data point of the threshold data. More specifically, processor 20 detects the time points at which the time-varying data becomes larger than the threshold data due to ripples, and calculates pulse data in which the detected time periods are defined as "true" and other times as "false." Note that in Fig. 5, "true" refers to the point at which the waveform rises, and "false" refers to other points.

[0035] For example, in FIG. 5, the time when the value of the time-varying data becomes larger (rising) than the threshold data due to the ripple is detected. As shown in FIG. 5, in this embodiment, only the time when the value of the time-varying data becomes larger than the threshold data is detected and the pulse data is determined to be "true." On the other hand, the time when the value of the time-varying data becomes smaller than the threshold data is not compared and the pulse data is determined to be "false." Furthermore, in this embodiment, the width (length of time) of each pulse in the pulse data is not particularly limited. In other words, the width of each pulse does not have to match the width (length of time) of the ripple.

[0036] As described above, in the driving device 10 according to this embodiment, ripples occur when the electrical connection between the brush 82 and the commutator 86 is switched. In other words, the number of pulses in the pulse data that are "true" corresponds to the number of pulses in which ripples occur.

[0037] 1, the number of brushes 82 and commutators 86 in motor 80 is predetermined based on the specifications of motor 80. For example, in the example of FIG. 1, since there are four commutators 86, four ripples will appear in the time-varying data before motor 80 makes one rotation.

[0038] Therefore, the processor 20, as the derivation unit 40, can count the number of "true"s included in the pulse data to derive the number of rotations of the motor 80 and the amount of movement of the moving object 90. Then, the processor 20 notifies the control unit 34 of the calculated number of rotations of the motor 80 or the amount of movement of the moving object 90.

[0039] (Procedure for controlling motor rotation speed) Then, the control unit 34, having received notification of the number of rotations of the motor 80 or the amount of movement of the object 90 to be moved, controls the number of rotations of the motor 80. For example, when the amount of movement of the object 90 to be moved reaches a predetermined amount, the control unit 34 may control the DC power supply 84 to stop the application of voltage (supply of DC current) to the motor 80. The control unit 34 may also control the DC power supply 84 to reverse the voltage of the DC power supply 84 supplied to the motor 80, thereby reversing the direction of rotation of the motor 80.

[0040] Further, an adjustment operation of the motor rotation speed detection method further performed by the motor rotation speed detection device 14 in this embodiment will be described with reference to FIGS.

[0041] (Adjustment of motor rotation speed detection method) The processor 20, functioning as the calculation unit 30, changes the predetermined time unit in accordance with the current value measured by the measurement unit 22. Specifically, as shown in Fig. 6, when calculating moving average data, if the current value measured by the measurement unit 22 is smaller than a predetermined threshold, the predetermined time unit is increased.

[0042] 6, for example, in the time-varying data, the sampling time S1 shortly after the motor 80 starts is shorter than the sampling time S2 when the rotation speed of the motor 80 has stabilized. More specifically, the sampling time S1 when the current value is greater than A1 is shorter than the sampling time S2 when the current value is smaller than A1. The current value A1 is an example of a predetermined threshold value in this modification.

[0043] Incidentally, when the power of DC motor 80 is not controlled, the current value immediately after starting (when the rotation speed is low) is larger than the current value when the rotation speed of motor 80 has stabilized (when the rotation speed is high). This is because the load (torque) on motor 80 is larger when the rotation speed of motor 80 is low than at other times.

[0044] Furthermore, when the current value flowing through motor 80 is large, i.e., when the rotation speed of motor 80 is low, the magnitude of the ripple also increases in accordance with the current value. In other words, when the current value flowing through motor 80 is small, i.e., when the rotation speed of motor 80 is stable, the magnitude of the ripple also decreases in accordance with the current value.

[0045] In this embodiment, the rate of change of the threshold data depends on the rate of change of the moving average data, which in turn depends on the length of the sampling time for calculating the moving average data. That is, in this embodiment, if the rate of change of the moving average data is large, the value of the time-varying data may exceed the threshold data due to noise superimposed on the threshold data. In other words, if the rate of change of the moving average data is large, the noise superimposed on the threshold data increases the possibility of false detection of ripples.

[0046] In this embodiment, when the current value of the time-varying data becomes smaller than a predetermined threshold A1, the sampling time is lengthened, as shown in Fig. 6. In other words, when the current value is smaller than the predetermined threshold, the motor rotation speed detection device 14 according to this aspect lengthens the predetermined time unit, thereby reducing the sensitivity of the threshold data to the time-varying data.

[0047] In this embodiment, the predetermined threshold value is the current setting value 48 recorded in the recording unit 28. In other words, the processor 20 changes the sampling time when the current value measured by the measuring unit 22 is smaller than the current setting value 48 read from the recording unit 28. Then, the processor 20 functions as the calculation unit 30 to create subsequent moving average data based on the changed sampling time.

[0048] Furthermore, in the above-described embodiment, when the current value is low, the number of detected ripples may be determined to be less than the expected number. Specifically, as shown in Fig. 7, although ripples are observed in the time-varying data, the time-varying data on which the ripples are superimposed may not be larger than the threshold data, and the ripples may not be detected. This is because, when the rotation speed of the motor 80 stabilizes and the current value decreases, the magnitude of the ripples decreases in accordance with the current value.

[0049] Therefore, in this embodiment, the processor 20, as the adder 32, changes the deviation amount B with respect to the magnitude of the measured current value relative to a predetermined threshold value. More specifically, as shown in FIG. 8, when it is determined that the number of ripples expected for the current value, i.e., the rotation speed of the motor 80, is small, the deviation amount B is reduced. For example, as shown by the dotted line in FIG. 8, the threshold data is reduced by a correction amount Δ to correct the deviation amount B to be smaller than the initial value. This reduces the value of the threshold data from the initial value. That is, FIGS. 7 and 8 show an example in which the deviation amount B is reduced when the current value is smaller than the predetermined threshold value.

[0050] In this embodiment, the magnitude of the measured current value relative to the predetermined threshold value is the pulse ratio set value 50 recorded in the recording unit 28. In other words, if the ratio between the current value measured by the measuring unit 22 and the number of ripples included in the pulse data is smaller than the pulse ratio set value 50 read from the recording unit 28, the processor 20 reduces the deviation amount B. Then, the processor 20, functioning as the adding unit 32, creates subsequent threshold data based on the changed threshold value.

[0051] In this way, the motor rotation speed detection device 14 according to this modified example adjusts the sensitivity of the threshold data to the time-varying data by changing the predetermined deviation amount B in accordance with the current value measured by the measurement unit 22.

[0052] In other words, the motor rotation speed detection device 14 according to this modified example increases the sensitivity of the threshold data to the time-varying data by reducing the predetermined deviation amount B when the current value is smaller than the predetermined threshold value.

[0053] The motor rotation speed detection device 14 according to this embodiment derives the rotation speed of the motor 80 based on threshold data that is sequentially calculated from time-varying data obtained by measuring the value of the current flowing through the motor 80. That is, the motor rotation speed detection device 14 according to this embodiment calculates the rotation speed of the motor 80 from the value of the current flowing through the motor 80, and therefore can detect the rotation speed of the motor 80 without a Hall IC. As a result, the motor rotation speed detection device 14 according to this embodiment can detect the rotation speed of the motor 80 with a simple configuration.

[0054] Furthermore, the motor rotation speed detection device 14 according to this embodiment adjusts the sensitivity of the threshold data to the time-varying data by changing the predetermined time unit in accordance with the current value measured by the measurement unit 22. This reduces erroneous detection or non-detection by the derivation unit in the motor rotation speed detection device 14 according to this embodiment, thereby improving the accuracy of deriving the rotation speed of the motor 80.

[0055] Furthermore, when the current value is smaller than a predetermined threshold, the motor rotation speed detection device 14 according to this embodiment increases the predetermined time unit to reduce the sensitivity of the threshold data to the time-varying data. This reduces false detections by the derivation unit in the motor rotation speed detection device 14 according to this embodiment, thereby improving the accuracy of deriving the rotation speed of the motor 80.

[0056] Furthermore, the motor rotation speed detection device 14 according to this embodiment adjusts the sensitivity of the threshold data to the time-varying data by changing the predetermined deviation amount B in accordance with the current value measured by the measurement unit 22. As a result, the motor rotation speed detection device 14 according to this embodiment can improve the accuracy of deriving the rotation speed of the motor 80, since erroneous detection or non-detection by the derivation unit is suppressed.

[0057] Furthermore, when the current value is smaller than a predetermined threshold, the motor rotation speed detection device 14 according to this embodiment increases the sensitivity of the threshold data to the time-varying data by reducing the predetermined deviation amount B. This reduces non-detection by the derivation unit in the motor rotation speed detection device 14 according to this embodiment, thereby improving the accuracy of deriving the rotation speed of the motor 80.

[0058] Furthermore, the control device 12 according to this embodiment performs the functions of the calculation unit 30, the addition unit 32, and the derivation unit 40 by the processor 20 executing the program 42 read from the recording unit 28. In other words, the control device 12 according to this embodiment measures the rotation speed of the motor 80 by software control. As a result, the control device 12 according to this embodiment can control the rotation speed of the motor 80 with a simple configuration.

[0059] Furthermore, the control device 12 according to this embodiment performs the functions of the calculation unit 30, the addition unit 32, and the derivation unit 40 by the processor 20 executing the program 42 read from the recording unit 28. In other words, the control device 12 according to this embodiment measures the rotation speed of the motor 80 by software control. As a result, the drive device 10 according to this embodiment can be provided with a motor 80 whose rotation speed is controlled by a simple configuration.

[0060] Furthermore, the motor rotation speed measurement method according to this embodiment derives the rotation speed of motor 80 based on threshold data that is obtained by sequentially calculating from time-varying data obtained by measuring the value of the current flowing through motor 80. That is, according to the motor rotation speed measurement method according to this embodiment, the rotation speed of motor 80 is calculated from the value of the current flowing through motor 80, so it is possible to measure the rotation speed of motor 80 that does not have a Hall IC. As a result, according to the motor rotation speed measurement method according to this embodiment, it is possible to measure the rotation speed of motor 80 with a simple configuration.

[0061] (Variation) In the above explanation, the adding unit 32 reduces the deviation amount B when the current value measured by the measuring unit 22 is smaller than the current setting value 48 recorded in the recording unit 28, but the motor rotation speed detection device 14 according to the present embodiment is not limited to this. For example, even when the rotation speed of the motor 80 is stable, if the ripple is sufficiently large and there is no need to reduce the deviation amount B (if it is fully expected that the time-varying data will become larger than the threshold data due to the ripple), the adding unit 32 does not need to reduce the deviation amount B.

[0062] Furthermore, in the above description, the adding unit 32 changes the deviation amount B based on the current value measured by the measuring unit 22 and the current setting value 48 recorded in the recording unit 28, but the motor rotation speed detecting device 14 according to this embodiment is not limited to this. For example, if the ripple is sufficiently large and there is no need to change the deviation amount B (if it is fully expected that the time-varying data will become larger than the threshold data due to the ripple), the adding unit 32 does not need to reduce the deviation amount B.

[0063] In the above description, calculation unit 30 increases the number of samples when the current value measured by measurement unit 22 is smaller than current setting value 48 recorded in recording unit 28, but motor rotation speed detection device 14 according to the present embodiment is not limited to this. For example, even when the rotation speed of motor 80 has stabilized, if the ripple is sufficiently large and there is no need to increase the number of samples (if it is fully expected that the time-varying data will exceed the threshold data due to the ripple even without changing the sensitivity), calculation unit 30 does not need to increase the number of samples.

[0064] Furthermore, in the above description, the calculation unit 30 changes the number of samples based on the current setting value 48 recorded in the recording unit 28, where the current value measured by the measurement unit 22 is measured. However, the motor rotation speed detection device 14 according to this embodiment is not limited to this. For example, if the ripple is sufficiently large and there is no need to change the number of samples (if it is sufficiently expected that the time-varying data will exceed the threshold data due to the ripple, even without changing the sensitivity), the calculation unit 30 does not need to reduce the deviation amount B.

[0065] In the above description, the recording unit 28 records the time setting value 44, deviation setting value 46, current setting value 48, and pulse ratio setting value 50, but the motor rotation speed detection device 14 according to this embodiment is not limited to this. For example, the various setting values ​​may be acquired from a device separate from the motor rotation speed detection device 14. Furthermore, the various setting values ​​may be values ​​measured as characteristic values ​​of the motor 80 when the motor rotation speed detection device 14 is incorporated into the drive device 10 together with the motor 80, and may be recorded as learning data. Alternatively, values ​​obtained when the drive device 10 is used may be stored as learning data.

[0066] Furthermore, in the above description, the control unit 34 in the control device 12 is configured separately from the motor rotation speed detection device 14, but the configuration of the control unit 34 according to the present disclosure is not limited to this. That is, the control unit 34 in the control device 12 may have the same configuration as the motor rotation speed detection device 14. More specifically, the processor 20 of the motor rotation speed detection device 14 may load the program 42 to perform the same functions as the control unit 34 in this embodiment.

[0067] In the above description, the calculation unit 30, the addition unit 32, and the derivation unit 40 are configured by the CPU executing the program 42, but the rotation speed detection device according to the present disclosure is not limited to this. In other words, the calculation unit 30, the addition unit 32, and the derivation unit 40 may be separate components as long as they perform the same functions as those described above.

[0068] The above describes an embodiment of the present disclosure with reference to the accompanying drawings. However, it is clear that a person with ordinary knowledge in the field of technology to which the present disclosure pertains can conceive of various modifications or applications within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0069] Further preferred aspects of the present disclosure will be described below.

[0070] (Appendix 1) a measuring unit that measures a current value flowing through the brushed motor; a storage unit that stores time-varying data that is a time-varying change in the current value measured by the measurement unit; a calculation unit that calculates moving average data from the time-varying data in a predetermined time unit; an adder that adds a predetermined deviation amount to the moving average data to calculate threshold data; a derivation unit that derives the rotation speed of the brushed motor based on the time when the value of the time-varying data becomes greater than the value of the threshold data; A brushed motor rotation speed detection device comprising:

[0071] (Appendix 2) the calculation unit changes the predetermined time unit in accordance with the current value measured by the measurement unit. 2. A brushed motor rotation speed detection device according to claim 1.

[0072] (Appendix 3) the calculation unit increases the predetermined time unit when the current value measured by the measurement unit is smaller than a predetermined threshold value; 3. A brushed motor rotation speed detection device according to claim 2.

[0073] (Appendix 4) the adding unit changes the predetermined deviation amount in accordance with the current value measured by the measuring unit. 4. A brushed motor rotation speed detection device according to any one of claims 1 to 3.

[0074] (Appendix 5) the adding unit reduces the predetermined deviation amount when the current value measured by the measuring unit is smaller than a predetermined threshold value; 5. A brushed motor rotation speed detection device according to claim 4.

[0075] (Appendix 6) A brushed motor rotation speed detection device according to any one of Supplementary Note 1 to Supplementary Note 5; a control unit that controls the brushed motor based on the rotation speed of the brushed motor derived by the deriving unit; A brushed motor control device comprising:

[0076] (Appendix 7) a brushed motor control device according to Supplementary Note 6; a brushed motor that moves an object to be moved; A drive device comprising:

[0077] (Appendix 8) The current value flowing through the brushed motor is measured and the time-varying data is stored. calculating a moving average from the time-varying data in a predetermined time unit to calculate moving average data; calculating threshold data by adding a predetermined deviation amount to the moving average data; deriving the rotation speed of the brushed motor based on the number of times the value of the time-varying data is greater than the value of the threshold data; How to measure the rotation speed of a brushed motor. [Explanation of symbols]

[0078] 10 Drive unit 12 Control device 14 Motor rotation speed detector (brush motor rotation speed detector) 20 processors 22 Measurement section 24 Shunt resistor 26 Memory section 28 Recording Section 30 Calculation Unit 32 Addition section 34 Control Unit 40 Derivation part 42 Programs 44 Time setting value (an example of a predetermined time unit) 46 Deviation setting value (an example of a predetermined deviation amount) 48 Current setting value (an example of a predetermined threshold value) 50 Pulse ratio setting value (an example of a predetermined threshold) 80 motor (an example of a brushed motor) 82 Brush 84 DC power supply 86 Commutator 90 Moving Objects

Claims

1. a measuring unit that measures a current value flowing through the brushed motor; a storage unit that stores time-varying data that is a time-varying change in the current value measured by the measurement unit; a calculation unit that calculates moving average data from the time-varying data in a predetermined time unit; an adder that adds a predetermined deviation amount to the moving average data to calculate threshold data; a derivation unit that derives the rotation speed of the brushed motor based on the time when the value of the time-varying data becomes greater than the value of the threshold data; A brushed motor rotation speed detection device comprising:

2. the calculation unit changes the predetermined time unit in accordance with the current value measured by the measurement unit.

2. The brushed motor rotation speed detection device according to claim 1.

3. the calculation unit increases the predetermined time unit when the current value measured by the measurement unit is smaller than a predetermined threshold value; 3. The brushed motor rotation speed detection device according to claim 2.

4. the adding unit changes the predetermined deviation amount in accordance with the current value measured by the measuring unit.

2. The brushed motor rotation speed detection device according to claim 1.

5. the adding unit reduces the predetermined deviation amount when the current value measured by the measuring unit is smaller than a predetermined threshold value; 5. The brushed motor rotation speed detection device according to claim 4.

6. The brushed motor rotation speed detection device according to any one of claims 1 to 5, a control unit that controls the brushed motor based on the rotation speed of the brushed motor derived by the deriving unit; A brushed motor control device comprising:

7. The brushed motor control device according to claim 6, a brushed motor that moves an object to be moved; A drive device comprising:

8. The current value flowing through the brushed motor is measured and the time-varying data is stored. calculating a moving average from the time-varying data in a predetermined time unit to calculate moving average data; calculating threshold data by adding a predetermined deviation amount to the moving average data; deriving the rotation speed of the brushed motor based on the number of times the value of the time-varying data is greater than the value of the threshold data; How to measure the rotation speed of a brushed motor.

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