JP7272888B2 - Rotation detector and motor drive device for detecting rotation information of rotating body - Google Patents

Description

The present invention relates to a rotation detector and a motor driving device for detecting rotation information of a rotating body.

2. Description of the Related Art Rotation detectors are used to detect rotation information such as rotational positions and rotational speeds of motors and rotary shafts provided in machine tools and robots. In the rotation detector, analog signals of two phases (A phase and B phase) with different phases, which are output according to the rotation of the rotating body from a sensor provided on the rotating body, are periodically (that is, constant Each interval) is analog-to-digital (AD) converted, and based on the two-phase digital signals obtained by this analog-to-digital conversion processing, rotational information regarding the rotational position (rotational angle) and rotational speed of the rotating body is calculated. . In a mechanical device that controls the rotation of a rotating body based on the rotation information obtained by a rotation detector, the latest digital signal is always used by periodically performing analog-to-digital conversion processing on each of the two-phase analog signals. Since the rotation information can be calculated, the rotation of the rotating body can be controlled with high accuracy. For example, in a motor drive device, a rotation detector for detecting rotation information of the rotor of the motor is provided near the rotor, and the rotation of the rotor of the motor is detected based on the rotation information detected by the rotation detector. controlled.

In addition, as a sensor provided on the rotating body, in addition to two-phase (A phase and B phase) analog signals that are periodically output according to the rotation of the rotating body, Some further output a reference position signal shown. The timing at which the reference position signal is output is used as the timing for acquiring rotation information (reference rotation information) that serves as a reference for increasing the accuracy of periodically acquired rotation information. As the reference position signal, for example, there is a one-rotation signal output from the sensor each time the rotating body makes one rotation.

In the rotation detector, when the rotating body reaches a specific rotational position, that is, when the reference position signal is output from the sensor, each of the two-phase (A-phase and B-phase) analog signals output from the sensor is detected. Analog-to-digital conversion is performed, and reference rotation information regarding the reference rotation position or reference rotation speed of the rotating body is acquired based on the digital signal obtained at this time. In the rotation detector, the reference rotation information is used as a relative reference measure of the rotation information obtained separately periodically. By appropriately adjusting the periodically obtained rotation information based on the reference rotation information, the rotation detection accuracy of the rotation detector can be improved.

For example, a rotor, a magnetic field generator that is fixed opposite to the rotor and generates a magnetic field, and the magnetic field generator that is arranged between the rotor and the magnetic field generator and based on the rotation of the rotor. and a detector for detecting a signal in response to a change in the magnetic field, wherein the rotor has a first cylindrical portion having one or more stages and one or more stages. a second cylindrical portion disposed coaxially with and axially offset from said first cylindrical portion, said second cylindrical portion having a first circumferential width narrower than said first cylindrical portion; a surface and a second circumferential portion having a radius less than the radius of the first circumferential portion; and the rotor includes a plurality of teeth formed on respective stages of the first cylindrical portion. and a first detected portion having the same phase and the same tooth profile dimensions as the tooth portion of the first detected portion, and formed on the first portion peripheral surface of the second cylindrical portion and a second detected portion including at least one tooth that has been set, the at least one tooth of the second cylindrical portion and the tooth of the first cylindrical portion that corresponds to the at least one tooth. is formed at once by machining (see, for example, Patent Document 1).

In addition to the above, various types of rotation detectors for detecting rotation information of motors, rotating shafts, etc. are known.

For example, a position control device for controlling a position for driving a drive section includes signal generation means for generating a signal corresponding to the drive of the drive section, and a multiplied signal generated from the signal generated by the signal generation means. A position control apparatus comprising: multiplication means; and change means for changing the multiplication number of said multiplication means, wherein said change means aligns the phases of the multiplied signals generated by said multiplication means before and after changing the multiplication number. is known (see, for example, Patent Document 2).

For example, a code wheel provided with a first scale and a second scale having different light reflection characteristics or light transmission characteristics and rotating in conjunction with a motor, a light source for irradiating the code wheel with light, and a detection means for detecting the origin position of the motor based on the light reflected or transmitted by the second scale; and light emitted by the light source and reflected or transmitted by the first scale and the second scale. and determining means for determining the absolute position of the motor based on the origin position detected by the detecting means (see, for example, Patent Document 3).

JP 2013-53990 A JP 2016-80547 A JP 2013-246054 A

In the rotation detector that acquires the reference rotation information using the reference position signal described above, the A-phase and B-phase One AD (analog-to-digital) converter is provided for each. That is, analog-to-digital conversion processing is executed by one AD converter for each of the two-phase analog signals. More specifically, the AD converters provided for each of the A phase and the B phase are periodically executed (ie, at regular intervals) to acquire the rotation information of the rotating body. It performs both digital conversion processing and analog-to-digital conversion processing that is executed when a reference position signal is detected (when the rotor reaches a specific rotational position) to obtain reference rotation information of the rotating body. Therefore, the analog-to-digital conversion processing at the time of detection of the reference position signal interrupts between analog-to-digital conversion processing that is performed periodically. Since the analog-to-digital conversion processing by the AD conversion section requires time on the order of several microseconds, depending on the timing of detection of the reference position signal, the execution timing of the periodic analog-to-digital conversion processing and the analog conversion processing at the time of detection of the reference position signal may vary. The execution timing of the digital conversion process may temporally overlap. In the rotation detector having one AD conversion unit for each of the A phase and the B phase, when the execution timings overlap as described above, priority is given to the execution of the analog-to-digital conversion processing when the reference position signal is detected. typical analog-to-digital conversion processing cannot be performed. In this case, the rotation information of the rotating body must be obtained by estimation processing such as uniform velocity interpolation based on the digital signal obtained by the previously executed analog-to-digital conversion processing. There is a problem that the accuracy is lowered. In particular, when the acceleration of the rotating body is large, the decrease in detection accuracy of the rotation detector is more pronounced.

Therefore, for each of the two-phase analog signals output in accordance with the rotation of the rotating body and having different phases, a single AD converter performs periodic analog-to-digital conversion processing and specific rotational position of the rotor. In a rotation detector that performs both analog-to-digital conversion processing upon arrival, it is desired to be able to detect rotation information regarding the rotational position or rotational speed of the rotating body with high accuracy.

According to one aspect of the present disclosure, a rotation detector that detects rotation information of a rotating body receives two-phase analog signals with different phases output from a sensor provided on the rotating body according to the rotation of the rotating body. , an AD conversion unit that performs analog-to-digital conversion processing to convert to a digital signal and output; Rotation information acquisition for acquiring information and obtaining reference rotation information regarding a reference rotation position or a reference rotation speed of the rotation body based on the digital signal output from the AD conversion unit each time the rotation body reaches a specific rotation position. a reference position signal detector that detects a reference position signal output from a sensor each time the rotating body reaches a specific rotational position; and a reference position signal detector that is executed when the reference position signal is detected. The execution timing of the first analog-to-digital conversion processing, which is an analog-to-digital conversion processing, and the first analog-to-digital conversion processing, which is an analog-to-digital conversion processing executed for outputting a digital signal used by the rotation information acquisition unit to acquire normal rotation information. and a determination unit that determines whether or not the execution timing of the analog-to-digital conversion processing of 2 overlaps in terms of time . When the reference position signal detection unit detects the reference position signal, the conversion unit executes analog-to-digital conversion processing, outputs a digital signal used by the rotation information acquisition unit to acquire the reference rotation information, and performs AD conversion. The unit does not execute the second analog-to-digital conversion processing when the determination unit determines that the execution timing of the first analog-to-digital conversion processing overlaps with the execution timing of the second analog-to-digital conversion processing. , a first analog-to-digital conversion process is executed .

According to one aspect of the present disclosure, one AD conversion unit performs periodic analog-to-digital conversion processing and Rotation information relating to the rotational position or rotational speed of the rotor can be detected with high precision in the rotation detector that performs both analog-to-digital conversion processing when the rotor reaches a specific rotational position.

FIG. 2 is a block diagram illustrating a rotation detector according to embodiments of the present disclosure; It is a figure which shows the magnetic sensor provided in a rotating body, (A) is a perspective view of a sensor, (B) is a side view of a sensor. 3A is a diagram for explaining the process of acquiring the rotational position of a rotating body based on two-phase analog signals whose phases are different from each other by about 90 degrees, FIG. (B) shows a comparator signal obtained by comparing the A-phase signal and B-phase signal at a predetermined level, and (C) shows the rotational position of the rotor on the AB coordinate plane. 3 is a diagram illustrating a one-rotation signal output from the sensor of FIG. 2; FIG. FIG. 10 is a diagram illustrating execution timings of AD conversion processing and rotation information acquisition processing in a conventional rotation detector; FIG. 5 is a diagram illustrating execution timings of AD conversion processing and rotation information acquisition processing in the rotation detector according to the embodiment of the present disclosure; FIG. 4 is a diagram for explaining estimation processing by interpolation of a rotation information acquisition unit in a rotation detector according to an embodiment of the present disclosure, (A) exemplifying execution timings of AD conversion processing and rotation information acquisition processing, and (B) A case where linear approximation is used for estimation processing by interpolation is shown. 4 is a diagram illustrating a data configuration of a digital signal for one phase obtained by an AD converter in the rotation detector according to the embodiment of the present disclosure; FIG. 1 is a block diagram illustrating a motor drive with a rotation detector according to an embodiment of the present disclosure; FIG.

A rotation detector for detecting rotation information of a rotating body and a motor drive device including the same will be described below with reference to the drawings. However, it should be understood that the invention is not limited to the drawings or the embodiments described below. Further, in the following description, the rotational position means the rotational angle of the rotating body, and the rotational speed means the rotational angular velocity of the rotating body.

FIG. 1 is a block diagram illustrating a rotation detector according to an embodiment of the present disclosure; FIG.

A rotation detector 1 for detecting rotation information of a rotating body 50 includes an AD conversion section 11 , a rotation information acquisition section 12 , a reference position signal detection section 13 and a determination section 14 .

A sensor 21 is installed on the rotating body 50 from which rotation information is detected. The sensor 21 outputs an A-phase signal and a B-phase signal, which are two-phase analog signals having different phases according to the rotation of the rotating body 50 . The phases of the A-phase signal and the B-phase signal differ by about 90 degrees, for example. The A-phase signal and B-phase signal output from the sensor 21 are sent to the AD converter 11 . In addition to the A-phase signal and the B-phase signal, the sensor 21 outputs a pulse-like reference position signal each time the rotor 50 reaches a specific rotational position. That is, every time the rotating body 50 reaches a specific rotational position, the reference position signal undergoes a signal change of "low (L), high (H), low (L)". In this specification, "to output a reference position signal" has the same meaning as "a signal change of low (L), high (H), and low (L) occurs in the reference position signal". As the sensor 21, the sensor 21 outputs a reference position signal that generates a signal change of "high (H), low (L), high (H)" each time the rotating body 50 reaches a specific rotational position. In this case, the following description applies by replacing "low (L), high (H), low (L)" with "high (H), low (L), high (H)". .

The specific rotational position of the rotating body 50 may be provided at one position during one rotation of the rotating body 50, or may be provided at a plurality of positions. For example, when one specific rotational position of the rotating body 50 for the reference position signal is provided during one rotation of the rotating body 50, the reference position signal is sent from the sensor 21 each time the rotating body 50 makes one rotation. This is the one-rotation signal to be output. In this case, the reference position signal (single-rotation signal) changes low (L), high (H), and low (L) only once each time the rotating body 50 makes one rotation. Further, for example, when a plurality of specific rotational positions of the rotating body 50 for the reference position signal are provided during one rotation of the rotating body 50, the reference position signal is generated from the sensor 21 during one rotation of the rotating body 50. It will be output multiple times. In this case, each time the rotating body 50 makes one rotation, the reference position signal changes from low (L) to high (H) to low (L) a plurality of times (that is, the number of specific rotation positions).

A reference position signal output from the sensor 21 is sent to the reference position signal detector 13 . The sensor 21 itself is not a limitation of this embodiment and may be magnetic or optical. A specific example of the sensor 21 will be described later.

The reference position signal detector 13 detects a reference position signal output from the sensor 21 each time the rotating body 50 reaches a specific rotational position. In this specification, "detecting the reference position signal" has the same meaning as "detecting low (L), high (H), and low (L) signal changes in the reference position signal".

The AD (analog-to-digital) converter 11 converts two-phase analog signals (A-phase signal and B-phase signal) output from the sensor 21 provided on the rotating body 50 according to the rotation of the rotating body 50 and having mutually different phases. Each of them is converted into a digital signal and output. The AD converter 11 includes an AD (analog-to-digital) converter that performs analog-to-digital conversion processing on the A-phase signal and an AD (analog-to-digital) converter that performs analog-to-digital conversion processing on the B-phase signal. Although provided separately, these two AD converters are collectively indicated as an AD converter 11 in FIG. A digital signal obtained by analog-to-digital conversion processing (hereinafter referred to as “AD conversion processing”) by the AD conversion section 11 is sent to the rotation information acquisition section 12 .

AD conversion processing by the AD conversion unit 11 includes a first AD conversion processing that is executed each time the body of rotation 50 reaches a specific rotational position for obtaining reference rotation information, and a normal rotation information processing. and a second AD conversion process that is periodically executed for acquisition. For example, if one specific rotational position of the rotating body 50 for the reference position signal is provided during one rotation of the rotating body 50, the first AD conversion process is performed every time the one-rotation signal is output from the sensor 21. is executed. Hereinafter, reference rotation information will be referred to as "reference rotation information", and normal rotation information will be referred to as "normal rotation information". The reference rotation information is information about a reference rotation position (hereinafter referred to as "reference rotation position") or a reference rotation speed (hereinafter referred to as "reference rotation speed") of the rotor 50. The normal rotation information is information about the normal rotation position (hereinafter referred to as "normal rotation position") or normal rotation speed (hereinafter referred to as "normal rotation speed") of the rotating body 50.

In the rotation detector 1, the reference rotation information is used as a relative reference for the normal rotation information obtained separately from this. That is, the rotation detection accuracy of the rotation detector 1 can be increased by appropriately adjusting the normal rotation information obtained periodically based on the reference rotation information. Although not shown in FIG. 1, the rotation detector 1 may further include an adjustment unit that adjusts the normal rotation information based on the reference rotation information.

In the present embodiment, the AD conversion unit 11 obtains normal rotation information during one cycle of normal rotation information acquisition by the rotation information acquisition unit 12, which will be described later (hereinafter referred to as "normal rotation information acquisition cycle"). is executed a plurality of times. Further, when the reference position signal detection unit 13 detects the reference position signal, it instructs the AD conversion unit 11 to perform the first AD conversion processing. A first AD conversion process is performed on each of the A-phase signal and the B-phase signal received from the sensor 21 to obtain a two-phase digital signal, which is output to the rotation information acquisition unit 12 .

Note that the first AD conversion process and the second AD conversion process are two-phase analog signals (A-phase signal and B-phase signal) output from the sensor 21 according to the rotation of the rotating body 50 and having mutually different phases. are converted into digital signals. The first AD conversion process is executed each time the rotating body 50 reaches a specific rotational position, whereas the second AD conversion process is periodically executed regardless of whether the rotating body 50 is rotating. They differ only in that Note that the analog-to-digital (AD) conversion result obtained by the second AD conversion processing may be used for normal rotation information estimation processing in the rotation information acquisition unit 12 as will be described later. not shown). The storage unit may be provided within the rotation information acquisition unit 12 as a function of a software program, or may be stored separately from the rotation information acquisition unit 12, such as an EEPROM (registered trademark). It may comprise recordable non-volatile memory or fast read/write random access memory such as DRAM, SRAM, or the like.

In this embodiment, the first AD conversion process, which is performed when the reference position signal is detected, interrupts between the second AD conversion processes, which are performed a plurality of times in the normal rotation information acquisition period. Since the AD conversion process by the AD converter 11 requires a time on the order of several microseconds, depending on the timing of detection of the reference position signal, the execution timing of the periodic AD conversion process and the AD conversion process at the time of detection of the reference position signal may vary. The execution timing of the conversion process may overlap in terms of time. The determination unit 14 is used by the rotation information acquisition unit 12 to acquire the normal rotation information and the execution timing of the first AD conversion process executed when the reference position signal detection unit 13 detects the reference position signal. It is determined whether or not the execution timing of the second AD conversion process that is executed to output the digital signal overlaps in terms of time. As long as the reference position signal detection unit 13 does not detect the reference position signal, the execution timing of the first AD conversion process and the execution timing of the second AD conversion process do not overlap. Therefore, the determination processing by the determination unit 14 may be executed only when the reference position signal detection unit 13 detects the reference position signal. A specific example of determination processing by the determination unit 14 will be described later.

When the determination unit 14 determines that the execution timing of the first AD conversion process and the execution timing of the second AD conversion process temporally overlap, the AD conversion unit 11 does not execute the second AD conversion process. The first AD conversion process is executed without A specific example of selective execution of AD conversion processing by the AD conversion unit 11 based on the determination result of the determination unit 14 will be described later.

Rotation information acquiring unit 12 acquires normal rotation information about the normal rotational position or normal rotational speed of rotating body 50 based on the digital signal output by AD converting unit 11 executing the second AD conversion process. It is acquired at each rotation information acquisition cycle (that is, at regular intervals). Further, upon receiving the reference position signal detection notification from the reference position signal detection unit 13, the rotation information acquisition unit 12, based on the digital signal output by the AD conversion unit 11 performing the first AD conversion processing, Reference rotation information about the reference rotation position or the reference rotation speed of the rotating body 50 is acquired. In this manner, the rotation information acquisition unit 12 acquires normal rotation information in each normal rotation information acquisition cycle, and acquires reference rotation information each time the rotating body 50 reaches a specific rotation position. The reference timing at which the normal rotation information acquisition process by the rotation information acquisition unit 12 is started may be defined by, for example, an interrupt signal from a mechanical device in which the rotation detector 1 is provided, or may be set within the rotation detector 1. It may be defined by a provided clock.

Note that if the determination unit 14 determines that the execution timing of the first AD conversion process and the execution timing of the second AD conversion process temporally overlap, the AD conversion unit 11 performs the second AD conversion process. Not executed. In this case, the rotation information acquisition unit 12 performs estimation processing by interpolation based on the digital signal output in the AD conversion processing executed by the AD conversion unit 11 prior to the first AD conversion processing. Get normal rotation information. The estimation processing by interpolation of the rotation information acquisition unit 12 will be described later.

As described above, in the rotation detector 1, the reference rotation information is used as a relative reference for the normal rotation information obtained separately from this, and is used to determine the rotation detection accuracy of the rotation detector 1. Contribute to raising That is, by using the reference rotation information (reference rotation position or reference rotation speed) acquired when the rotor 50 reaches a specific rotation position as the origin (reference point), more accurate normal rotation information (normal rotation position or normal rotation speed) can be obtained.

The rotation information acquisition unit 12, the reference position signal detection unit 13, and the determination unit 14 described above may be constructed, for example, in the form of a software program, or may be constructed by combining various electronic circuits and software programs, or may be constructed by combining various electronic circuits and software programs. It may be composed only of an electronic circuit. For example, when constructing these in a software program format, the functions of the above-described units can be realized by operating an arithmetic processing unit such as ASIC, DSP, or FPGA according to this software program. Alternatively, the rotation information acquisition unit 12, the reference position signal detection unit 13, and the determination unit 14 may be implemented as a semiconductor integrated circuit in which a software program that implements the functions of each unit is written. Alternatively, the rotation information acquisition section 12, the reference position signal detection section 13, and the determination section 14 may be implemented as a recording medium in which a software program that implements the functions of each section is written.

Further, the AD conversion unit 11 described above is configured by, for example, a successive approximation type AD (analog-to-digital) converter, but may be configured by other AD converters.

Further, the sensor 21 described above outputs an A-phase signal and a B-phase signal, which are two-phase analog signals whose phases are different from each other by about 90 degrees, according to the rotation of the rotating body 50. It may be of a magnetic type or an optical type, as long as it outputs a reference position signal every time it reaches the position. As an example, a magnetic sensor 21 capable of outputting a one-rotation signal as a reference position signal will be described with reference to FIGS. 2 to 4. FIG.

2A and 2B are diagrams showing a magnetic sensor provided on a rotating body, where (A) is a perspective view of the sensor and (B) is a side view of the sensor.

For example, the sensor 21 is configured by providing a first cylindrical portion 110 and a second cylindrical portion 120 as sensor gears around the rotating body 50 . Teeth 115 and 115a are provided on the first partial peripheral surface 121 of the first cylindrical portion 110 for generating an A-phase signal and a B-phase signal, which are two-phase analog signals having mutually different phases. A toothing 125 is provided on the second partial circumference 122 of the second cylindrical section 120 for the generation of the one-turn signal. A magnet 130 is installed facing a portion of the rotating body 50 . This magnet 130 functions as a magnetic field generator that generates a magnetic field. Furthermore, two magnetoresistive elements 131 and 132 are installed between the magnet 130 and the rotor 50 . The first magnetoresistive element 131 is an AB-phase signal sensor that detects two-phase analog signals consisting of an A-phase signal and a B-phase signal that are out of phase with each other by about 90 degrees. It is arranged at a position corresponding to the portion 110 . The second magnetoresistive element 132 is a one-rotation signal sensor that detects a one-rotation signal (Z-phase signal) that is generated only once while the rotating body 50 makes one rotation. It is arranged at a position corresponding to 120 .

3A and 3B are diagrams for explaining the process of acquiring the rotational position of the rotating body based on two-phase analog signals whose phases are different from each other by about 90 degrees. A B-phase signal is shown, (B) shows a comparator signal obtained by comparing the A-phase signal and B-phase signal at a predetermined level, and (C) shows the rotational position of the rotating body on the AB coordinate plane. In FIGS. 3A and 3B, the A-phase signal is indicated by a solid line, and the B-phase signal is indicated by a broken line. The magnetic flux from magnet 130 passes through first magnetoresistive element 131 and returns to magnet 130 through first cylindrical portion 110 of rotating body 50 . When the rotating body 50 is rotated around its center by a drive section (not shown), the magnetic resistance of the first magnetic resistance element 131 changes due to the teeth 115 . As a result, as shown in FIG. 3A, the sensor 21 outputs an A-phase signal and a B-phase signal, which are two-phase analog sinusoidal signals whose phases are different from each other by about 90 degrees. The A-phase signal and B-phase signal output from the sensor 21 are sent to the AD converter 11 and are analog-to-digital (AD) converted. Based on the A-phase and B-phase digital signals output from the AD converter 11, the rotation information acquisition unit 12 determines the rotation of the rotor 50 during one rotation of the rotor 50 as shown in FIG. Get position. The amount of rotation of the rotating body 50 can be obtained by counting high (H) and low (L) in each of the A-phase and B-phase digital signals. It can be obtained from the phase difference between each digital signal of the phase. When the rotation detector 1 is requested to output the rotational speed of the rotating body 50 , the rotation information acquisition unit 12 acquires the rotational speed of the rotating body 50 by differentiating the rotational position of the rotating body 50 . Rough information for each tooth portion 115 of the first cylindrical portion 110, which is the sensor gear, can be obtained from the comparator signal shown in FIG. 3B. In acquiring the rotational position of the rotating body 50 during one rotation of the rotating body 50, not only the A-phase signal and B-phase signal shown in FIG. 3(A) but also the comparator signal shown in FIG. 3(B) may be used. .

FIG. 4 is a diagram illustrating a one-rotation signal output from the sensor of FIG. 2; Magnetic flux from magnet 130 passes through second magnetoresistive element 132 and returns to magnet 130 through second cylindrical portion 120 of rotating body 50 . When the rotating body 50 is rotated around its center by a driving section (not shown), the magnetic resistance of the second magnetic resistance element 132 is changed by the teeth 125 . When the output voltage from the second magnetoresistive element 132 is compared at a predetermined level, a pulse-like one-rotation signal as shown in FIG. 4 is obtained. Since one tooth portion 125 is provided on the second partial peripheral surface 122 of the second cylindrical portion 120, each time the rotating body 50 makes one rotation, "low (L), high (H), low ( L)” occurs only once. A one-rotation signal output from the sensor 21 is sent to the one-rotation signal detection section 13 . When the one-rotation signal detection unit 13 detects the one-rotation signal, that is, when it detects a signal change of “low (L), high (H), low (L)”, the one-rotation signal detection unit 13 sends a first signal to the AD conversion unit 11 . 1, and notifies the rotation information acquiring unit 12 of detection of a one-rotation signal. If a plurality of tooth portions 125 are provided on the second partial peripheral surface 122 of the second cylindrical portion 120, during one rotation of the rotor 50, "low (L), high (H), low (L)” occurs a plurality of times (that is, the number of teeth 125).

2 to 4, the case where one sensor 21 that outputs both the A-phase signal, the B-phase signal, and the one-rotation signal (reference position signal) is attached to the rotating body 50 has been described. As an alternative example, a sensor for outputting the A-phase signal and the B-phase signal and a sensor for outputting the one-rotation signal (reference position signal) may be attached to the rotor 50 separately.

Further, the sensor 21 for detecting the A-phase signal, the B-phase signal and the reference position signal from the rotating body 50 is not limited to the magnetic type described with reference to FIGS. 2 to 4, and may be an optical type. The optical sensor 21 outputs an A-phase signal, a B-phase signal, and a reference position signal based on the brightness change of the transmitted light or the reflected light that changes according to the rotation of the rotating body 50 .

Subsequently, specific examples of the determination processing of the determination unit 14 in the rotation detector 1 according to the embodiment of the present disclosure and the selective execution of the AD conversion processing by the AD conversion unit 11 based on the determination result will be compared with a conventional rotation detector. I will explain while

FIG. 5 is a diagram illustrating execution timings of AD conversion processing and rotation information acquisition processing in a conventional rotation detector.

In FIG. 5, T is the acquisition cycle of normal rotation information. In the conventional rotation detector, the normal rotation information obtaining process and the second AD conversion process for obtaining the normal rotation information are in one-to-one correspondence, and both are executed at the same cycle T. In the example shown in FIG. 5, the second AD conversion process Q11 is executed immediately before the normal rotation information acquisition process S1 started at time _t0 , and the normal rotation information acquisition process started at time _t2 . A second AD conversion process Q21 is executed immediately before S2 corresponding to S2. Also, the second AD conversion process Q31 should be executed immediately before the normal rotation information acquisition process S3 that starts at time _t4 . However, when the reference position signal is detected at time _tx immediately before time _t4 (i.e., when a signal change of "low (L), high (H), low (L)" is detected), AD The conversion unit executes a first AD conversion process P for obtaining reference rotation information. The AD conversion processing by the AD conversion unit requires time on the order of several microseconds. When the time t _x is earlier than the time t ₄ by a time shorter than the time required for the AD conversion process, the execution timing of the first AD conversion process P and the execution timing of the second AD conversion process Q31 overlaps. In this case, the AD converter starts executing the first AD conversion process P at the time _tx , so it cannot execute the second AD conversion process Q31. Therefore, since the digital signal obtained by the second AD conversion processing Q31 cannot be obtained, in the normal rotation information acquisition processing S3, the digital signal obtained by the previously executed second AD conversion processing Q11 and Q21 is Based on this, it is necessary to acquire the rotation information of the rotating body by estimation processing such as uniform velocity interpolation.

FIG. 6 is a diagram illustrating execution timings of AD conversion processing and rotation information acquisition processing in the rotation detector according to the embodiment of the present disclosure. Here, as an example, a case where the reference position signal detector 13 detects the reference position signal at time _tx between time _t3 and time _t4 will be described.

In FIG. 6, T is the normal rotation information acquisition period of the rotation information acquisition unit 12 . That is, the rotation information acquisition unit 12 executes the rotation information acquisition process S1 at time _t0 , executes the rotation information acquisition process S2 at time _t2 after one cycle T from time _t0 , and executes the rotation information acquisition process S2 for one cycle from time _t2 . At time _t4 after T, the rotation information acquisition process S3 is executed.

Aside from the first AD conversion process P, the AD conversion unit 11 periodically executes a second AD conversion process for acquiring normal rotation information. The second AD conversion process is executed multiple times during one cycle T of the normal rotation information acquisition cycle. In the example shown in FIG. 6, it is executed twice during one cycle T. During one cycle T, the second AD conversion process may be performed at uniform intervals or at non-uniform intervals.

The AD converter 11 executes the second AD conversion process Q11 immediately before time _t0 . In addition, during one cycle T from time _t0 to time _t2 , the AD conversion unit 11 executes the second AD conversion process _Q12 just before time t1, which is midway between time _t0 and time _t2 . Then, immediately before time _t2 , the second AD conversion process Q21 is executed.

During one cycle T from time _t2 to time _t4 , the AD conversion unit 11 executes the second AD conversion process _Q22 immediately before time t3, which is midway between time _t2 and time _t4 . do.

Here, when the reference position signal detector 13 detects the reference position signal at time _tx between time _t3 and time _t4 (i.e., "low (L), high (H), low (L)" ), the AD conversion unit 11 detects each of the two-phase analog signals (A-phase signal and B-phase signal) output from the sensor 21 and having different phases to acquire the reference rotation information. A first AD conversion process P is executed for the purpose. At time t _x , the determination unit 14 determines whether or not the execution timing of the first AD conversion process P and the execution timing of the second AD conversion process Q31 temporally overlap. When the time t _x is earlier than the time t ₄ by a time shorter than the time required for the AD conversion process, the execution timing of the first AD conversion process P and the execution timing of the second AD conversion process Q31 overlaps with In this case, the determination unit 14 determines that the execution timing of the first AD conversion process P and the execution timing of the second AD conversion process Q31 temporally overlap. Since the determination unit 14 has determined that the execution timing of the first AD conversion process and the execution timing of the second AD conversion process overlap, the AD conversion unit 11 does not execute the second AD conversion process Q31. The first AD conversion process P is executed without Although not shown in FIG. 6, the rotation information acquisition unit 12 obtains the reference rotation position or reference rotation position of the rotating body 50 based on the digital signal output by the AD conversion unit 11 executing the first AD conversion processing P. Get reference rotation information about speed. Further, as shown in FIG. 6, the rotation information obtaining unit 12 cannot obtain the digital signal obtained by the second AD conversion processing Q31. Based on the digital signals obtained by the AD conversion processes Q21 and S22, the normal rotation information of the rotating body 50 is acquired by an estimation process such as uniform velocity interpolation.

Here, with respect to the normal rotation information acquisition process S3 that starts to be executed at time _t4 , the operation of the conventional rotation detector shown in FIG. 5 and the operation of the rotation detector 1 according to the embodiment of the present disclosure shown in FIG. compare. In _the conventional rotation detector shown in FIG. ₅ , the digital Rotation information of the rotating body is obtained by estimation processing such as uniform velocity interpolation based on the signal. On the other hand, in the rotation detector 1 according to the embodiment of the present disclosure shown in _{FIG .} Based on the digital signal obtained by the conversion processing Q22, rotation information of the rotating body is obtained by estimation processing such as uniform velocity interpolation. As described above, in the rotation detector 1 according to the embodiment of the present disclosure, compared to the conventional rotation detector, _{the second} Rotation information can be acquired based on the digital signal output by the AD conversion process of . Thus, the rotation detector 1 according to the embodiments of the present disclosure has higher detection accuracy than conventional rotation detectors, as rotation information can be calculated using "fresher" digital signals.

It should be noted that executing the normal rotation information acquisition process immediately after each of the second AD conversion processes that are executed multiple times in one cycle T imposes a burden on the arithmetic processing unit that realizes the function of the rotation information acquisition unit 12. This is not preferable because Therefore, in the rotation detector 1 according to the embodiment of the present disclosure, the execution frequency of the normal rotation information processing is maintained at the same level as in the conventional art, while the execution frequency of the second AD conversion processing for acquiring the normal rotation information is increased. As a result, the detection accuracy of the rotation detector 1 can be increased without imposing a burden on the arithmetic processing device that implements the functions of the rotation information acquisition section 12 .

In addition, in the example shown in FIG. 6, the number of executions of the second AD conversion process during one cycle T of the normal rotation information acquisition cycle is two times as an example. In the present embodiment, the greater the number of executions of the second AD conversion process during one period T of the normal rotation information acquisition period, the shorter the interval between execution timings of the second AD conversion process. Therefore, as the number of executions of the second AD conversion process during one cycle T of the normal rotation information acquisition cycle increases, the rotation information acquisition unit 12 detects the second AD conversion process executed in the past at a timing closer to the original execution timing. Since the digital signal output by the AD conversion process can be used, the detection accuracy is further improved.

Next, a specific example of estimation processing by interpolation of the rotation information acquisition unit 12 in the rotation detector 1 according to the embodiment of the present disclosure will be described.

FIG. 7 is a diagram for explaining estimation processing by interpolation of the rotation information acquisition unit in the rotation detector according to the embodiment of the present disclosure. (B) shows a case where linear approximation is used for estimation processing by interpolation. Here, as an example, the second AD conversion process is executed three times at irregular intervals during one cycle T of the normal rotation information acquisition cycle, and at time t _x between time t ₃ and time t ₄ A case where the reference position signal detector 13 detects the reference position signal will be described.

As shown in FIG. 7A, immediately before time _t0 , the AD converter 11 executes the second AD conversion process Q11. The rotation information acquisition unit 12 executes normal rotation information acquisition processing S1 for acquiring normal rotation information based on the digital signal D11 output in the second AD conversion processing Q11 at time _t0 .

Immediately before time _t1 , the AD converter 11 executes a second AD conversion process Q12 and outputs a digital signal D12. Further, immediately before time _t2 , the AD converter 11 executes a second AD conversion process Q13 and outputs a digital signal D13.

At time _tx between time _t3 and time _t4 , when the reference position signal detector 13 detects the reference position signal (i.e., the signal change of "low (L), high (H), low (L)" is detected), the AD conversion unit 11 outputs the first signal for obtaining the reference rotation information for each of the two-phase analog signals (the A-phase signal and the B-phase signal) output from the sensor 21 and having different phases. 1 AD conversion processing P is executed. Also, at time t _x , the determination unit 14 determines whether or not the execution timing of the first AD conversion process P and the execution timing of the second AD conversion process Q31 temporally overlap. When the time t _x precedes the time t ₄ by a time shorter than the time required for AD conversion processing, the execution timing of the first AD conversion processing P and the execution timing of the second AD conversion processing Q21 overlaps with In this case, the determination unit 14 determines that the execution timing of the first AD conversion process P and the execution timing of the second AD conversion process Q21 temporally overlap. Based on this determination result, the AD converter 11 executes the first AD conversion process P without executing the second AD conversion process Q21. Although not shown in FIG. 7, the rotation information acquisition unit 12 obtains the reference rotation position or reference rotation position of the rotating body 50 based on the digital signal output by the AD conversion unit 11 executing the first AD conversion processing P. Get reference rotation information about speed.

Further, since the rotation information acquisition unit 12 cannot acquire a digital signal by the second AD conversion processing Q21, in the normal rotation information acquisition processing S2, for example, by the second AD conversion processing Q11 executed previously, Based on the obtained digital signal D11, the digital signal D12 obtained by the second AD conversion processing Q12, and the digital signal D13 obtained by the second AD conversion processing Q13, the first The digital signal D21 obtained by the AD conversion process Q21 of No. 2 is estimated, and the normal rotation information acquisition process S2 for acquiring the normal rotation information of the rotor 50 is executed based on the estimated digital signal D21.

In the normal rotation information acquisition process S2 by the rotation information acquisition unit 12, when the digital signal D21 is calculated using an approximate straight line, for example, when the estimated value of the digital signal at time t is _D , the estimated value is calculated as follows: The approximation straight line is represented by Equation 1 below.

For example, when obtaining the slope α and the intercept β of the approximate straight line shown in Equation 1 using the least squares method, the values of the digital signal D11, the digital signal D12, and the digital signal D13 are obtained for each of the A phase and the B phase. used for Further, for example, when the slope α and the intercept β of the approximate straight line shown in Equation 1 are obtained using first-order approximation (linear approximation), two values of the digital signal D11, the digital signal D12, and the digital signal D13 are used as A It is used for each phase of phase and B phase. The rotation information acquiring unit 12 substitutes the time _{t3 into} Equation 1 having the slope α and the intercept β of the approximate straight line calculated in this way, so that the first It is possible to estimate the digital signal D21 for two phases obtained in the AD conversion process Q21 of 2.

As described above, in the estimation processing by interpolation of the rotation information acquisition unit 12, the analog data obtained by the past second AD conversion processing that was executed before the second AD conversion processing that could not be executed. Time information is required along with the digital (AD) conversion result. Therefore, the digital signal obtained by the second AD conversion processing by the AD converter 11 is provided with time information in addition to the analog-to-digital conversion result. FIG. 8 is a diagram illustrating a data configuration of a digital signal for one phase obtained by an AD converter in the rotation detector according to the embodiment of the present disclosure; As shown in FIG. 8, the digital signal output by the second AD conversion process by the AD converter 11 is the result of analog-to-digital conversion of the analog signal (phase A signal or phase B signal) output from the sensor 21. It consists of a data part and a data part consisting of time information when the analog-to-digital conversion result is obtained. As an example, the time data shown in FIG. 8 represents a time period within one cycle of the normal rotation information acquisition cycle with 8 bits. The numerical values shown in FIG. 8 are merely examples, and other numerical values may be used.

The rotation detector 1 according to the embodiment of the present disclosure described above can be used for controlling the rotation of a rotating body in a mechanical device having the rotating body.

FIG. 9 is a block diagram illustrating a motor drive with a rotation detector according to an embodiment of the present disclosure; Here, as an example, a case in which the motor drive device 1000 controls the motor 3 based on the AC power supplied from the AC power supply 2 will be described. The number of phases of the AC power supply 2 and the motor 3 is not particularly limited in this embodiment, and may be, for example, three-phase AC or single-phase AC. Also, the type of the motor 3 is not particularly limited in this embodiment, and may be, for example, an induction motor or a synchronous motor. In addition to machine tools and robots, the machines provided with the motor 3 include forging machines, injection molding machines, industrial machines, various electrical appliances, trains, automobiles, and aircraft. Examples of the AC power supply 2 include a three-phase AC 400V power supply, a three-phase AC 200V power supply, a three-phase AC 600V power supply, and a single-phase AC 100V power supply.

As shown in FIG. 9 , motor drive device 1000 includes rectifier 101 , inverter 102 , motor controller 103 , and rotation detector 1 .

The rectifier 101 converts AC power on the AC power supply 2 side into DC power and outputs the power to the DC side. The rectifier 101 is configured as a three-phase bridge circuit when three-phase alternating current is supplied from the alternating current power supply 2, and is configured as a single-phase bridge circuit when single-phase alternating current is supplied from the alternating current power supply 2. The rectifier 101 is composed of, for example, a diode rectifier circuit, a 120-degree conduction rectifier circuit, a PWM switching control type rectifier circuit, or the like. For example, if the rectifier 101 is a PWM switching control type rectifier circuit, it is composed of a switching element and a bridge circuit of diodes connected in anti-parallel to the switching element. Each switching element is on/off-controlled to perform power conversion in both AC and DC directions. Examples of switching elements include unipolar transistors such as FETs, bipolar transistors, IGBTs, thyristors, and GTOs. good.

Note that the rectifier 101 may be omitted when the motor 3 is controlled based on a DC power source such as a battery instead of an AC power source.

The inverter 102 converts the DC power supplied from the DC side into AC power for driving the motor 3 and outputs the AC power. The inverter 102 is configured by, for example, a PWM inverter including semiconductor switching elements inside. Inverter 102 is configured as a three-phase bridge circuit when motor 3 is a three-phase AC motor, and is configured as a single-phase bridge circuit when motor 3 is a single-phase motor. When the inverter 102 is composed of a PWM inverter, it is composed of a semiconductor switching element and a diode bridge circuit connected in anti-parallel thereto. In this case, examples of semiconductor switching elements include FETs, IGBTs, thyristors, GTOs (Gate Turn-OFF thyristors), SiCs (silicon carbide), and transistors. The embodiment is not limited, and other semiconductor switching elements may be used.

A sensor 21 is provided near the rotor of the motor 3 . The rotation detector 1 according to the embodiment of the present disclosure detects the rotor 51 of the motor, which is the rotating body 50 , based on the two-phase analog signals (A-phase signal and B-phase signal) output from the sensor 21 and having different phases. Detects the rotation information of Rotation information detected by the rotation detector 1 is sent to the motor control unit 103 .

Motor control unit 103 controls the power conversion operation of inverter 102 . That is, the motor control unit 103 controls rotation information of the rotor 51 of the motor 3 detected by the rotation detector 1, current flowing through the windings of the motor 3 (current feedback), a predetermined torque command, and an operation program of the motor 3. Based on such as, a drive command for controlling the speed and torque of the motor 3 or the position of the rotor is generated according to the PWM control method. Power conversion operation by the inverter 102 is controlled based on the drive command generated by the motor control unit 103 . The speed, torque, or position of the rotor of the motor 3 is controlled based on, for example, voltage-variable and frequency-variable AC power supplied from the inverter 102 . The motor control unit 103 may be constructed, for example, in the form of a software program, or may be constructed by combining various electronic circuits and software programs. For example, when constructing them in a software program format, the functions of the motor control unit 103 can be realized by operating an arithmetic processing unit such as a DSP or FPGA according to this software program. Alternatively, the motor control unit 103 may be implemented as a semiconductor integrated circuit in which a software program that implements the functions of each unit is written.

In this way, the motor drive device 1000 controls the rotation of the rotor 51 of the motor 3 based on the rotation information detected by the rotation detector 1 according to the embodiment of the present disclosure, thereby realizing highly accurate motor control. be able to.

1 rotation detector 2 AC power supply 3 motor 11 AD converter 12 rotation information acquisition unit 13 reference position signal detection unit 14 determination unit 21 sensor 50 rotor 51 rotor 101 rectifier 102 inverter 103 motor control unit 110 first cylindrical portion 115 , 115a, 125 tooth portion 120 second cylindrical portion 121 first partial peripheral surface 122 second partial peripheral surface 130 magnet 131 first magnetic resistance element 132 second magnetic resistance element 1000 motor drive device

Claims (4)

A rotation detector for detecting rotation information of a rotating body,
An AD converter for executing analog-to-digital conversion processing for converting two-phase analog signals having different phases output from a sensor provided on the rotating body according to the rotation of the rotating body into digital signals and outputting the analog signals. and,
For each cycle, normal rotation information about the rotational position or rotational speed of the rotating body is acquired based on the digital signal output from the AD conversion unit, and each time the rotating body reaches a specific rotational position, a rotation information acquisition unit that acquires reference rotation information about a reference rotation position or a reference rotation speed of the rotating body based on the digital signal output from the AD conversion unit;
a reference position signal detection unit that detects a reference position signal output from the sensor each time the rotating body reaches a specific rotational position;
execution timing of a first analog-to-digital conversion process which is the analog-to-digital conversion process executed when the reference position signal detection unit detects the reference position signal; and the rotation information acquisition unit acquires the normal rotation information. a determination unit that determines whether or not the execution timing of the second analog-to-digital conversion processing, which is the analog-to-digital conversion processing executed to output the digital signal used for
with
The AD conversion unit executes the analog-to-digital conversion process a plurality of times during the one cycle,
When the reference position signal detection section detects the reference position signal, the AD conversion section executes the analog-to-digital conversion processing, and the rotation information acquisition section performs the digital signal used by the rotation information acquisition section to acquire the reference rotation information. output a signal,
The AD conversion unit converts the second analog-digital A rotation detector that performs the first analog-to-digital conversion process without performing a digital conversion process . When the judging unit judges that the execution timing of the first analog-to-digital conversion process and the execution timing of the second analog-to-digital conversion process overlap in terms of time, the rotation information acquisition unit performs the first 2. The rotation detector according to claim 1 , wherein said normal rotation information is acquired based on said digital signal output in analog-to-digital conversion processing executed by said AD conversion section prior to analog-to-digital conversion processing. 3. The rotation detector according to claim 1, wherein said reference position signal is a one-rotation signal output from said sensor each time said rotating body rotates once . The rotation detector according to any one of claims 1 to 3 , which detects rotation information of the rotor of the motor, which is the rotating body;
an inverter that converts the DC power supplied from the DC side into AC power for driving the motor and outputs it;
a motor control unit that controls a process of converting the DC power to the AC power by the inverter based on the rotation information detected by the rotation detector;
A motor drive device.

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