JP2015159709A - Motor controller and correction data creation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance accuracy of motor control by creating the correction data used in a motor controller, for controlling a motor based on the signal outputted from a sensor such as a resolver or an encoder, with high accuracy.SOLUTION: While driving a motor in a forward drive pattern, including a constant speed region where the rotating shaft rotates forward at a constant speed, a command signal is sampled when the rotating shaft rotates forward one revolution or more in the constant speed region, and command information during forward rotation is acquired. While driving a motor in a backward drive pattern, including a constant speed region where the rotating shaft rotates backward at a constant speed, a command signal is sampled when the rotating shaft rotates backward one revolution or more in the constant speed region, and command information during backward rotation is acquired. Correction data is created using the command information during forward rotation, and the command information during backward rotation.

Description

  The present invention is obtained by generating a position detection signal of a rotating shaft based on a signal output from a sensor such as a resolver or an encoder connected to the rotating shaft of the motor, and further correcting the position detection signal with correction data. The present invention relates to a motor control apparatus that controls a motor by feeding back a corrected position signal, and a correction data generation method that generates correction data used in the apparatus.

  In the motor control technology, it is necessary to detect the rotational position of the rotary shaft in order to obtain a positional deviation between the position command and the actual rotational position of the rotary shaft of the motor. One of the position detecting means is a resolver. Here, when a resolver is used, a position correction technique that takes into account the position detection error of the resolver is required. Therefore, for example, in the devices described in Patent Document 1 and Patent Document 2, correction data is stored in a memory in advance, and a position detection signal created based on a signal output from the resolver is corrected with correction data during motor control. Thus, a corrected position signal is created, and the motor is feedback-controlled using the corrected position signal.

Japanese Patent No. 2541169 Japanese Patent No. 5281102

  In Patent Document 1 and Patent Document 2, correction data is created from a position detection signal detected by a resolver. However, the correction data is not necessarily highly accurate, and position detection is performed using the correction data. Even if the signal is corrected, it is difficult to control the motor with high accuracy.

  The present invention has been made in view of the above problems, and can accurately create correction data used in a motor control device that controls a motor based on a signal output from a sensor such as a resolver or an encoder. The purpose is to improve the accuracy of control.

  The first aspect of the present invention generates a position detection signal related to the rotational position of the rotating shaft based on a signal output from the sensor corresponding to the rotational angle of the rotating shaft of the motor rotating in response to the command signal, A correction data generation method for generating correction data in a motor control device that controls a motor by feeding back a corrected position signal obtained by correcting a position detection signal with correction data, and a rotating shaft rotates forward at a constant speed. While driving the motor with a forward drive pattern that includes a constant speed region, the command signal is sampled while the rotating shaft rotates forward one or more times in the constant speed region to obtain command information during normal rotation. Reverse rotation obtained by sampling the command signal while driving the motor with a backward drive pattern including a constant speed region that rotates in the reverse direction while the rotating shaft rotates backward one or more times in the constant speed region Time acquires command information, is characterized in that to create the correction data by using a forward rotation command information and the reverse rotation time of command information.

  Further, the second aspect of the present invention generates a position detection signal related to the rotational position of the rotating shaft based on a signal output from the sensor corresponding to the rotational angle of the rotating shaft of the motor rotating in response to the command signal. A motor control apparatus that controls a motor by feeding back a corrected position signal obtained by correcting a position detection signal with correction data, and includes a correction data generation unit that generates correction data, and generates correction data. Sometimes, the motor drive unit has a forward drive pattern that drives the motor in a forward drive pattern that includes a constant speed region in which the rotation axis rotates forward at a constant speed, and a return drive pattern that includes a constant speed region in which the rotation shaft rotates in reverse at a constant speed. The correction data creation unit samples the command signal during the forward path drive while the forward rotation of the rotating shaft is forward or more in the constant speed region, and corrects it. Rotational command information is acquired, reverse rotation command information obtained by sampling a command signal while the rotary shaft rotates backward or more in the constant speed region during backward drive, and forward rotation command information and It is characterized in that correction data is created using the reverse rotation command information.

  In the invention configured as described above, the forward rotation command information and the reverse rotation command information are respectively acquired while driving the motor with the forward drive pattern and the backward drive pattern. This command information at the time of normal rotation is obtained by sampling the command signal while the rotation axis rotates positively one or more times in a constant speed region. Further, the reverse rotation command information is obtained by sampling the command signal while the rotation axis rotates reversely by one rotation or more in a constant speed region. Therefore, as will be described in detail later, the error increasing direction and the phase changing direction included in the forward rotation direction command information and the reverse rotation direction command information are opposite to each other. Correction data can be created with high accuracy from the time command information and the reverse rotation command information. Further, the accuracy of motor control is improved by performing feedback control using the correction data thus created.

  As described above, according to the present invention, the correction data used in the motor control device is created using the forward rotation direction command information and the reverse rotation direction command information, so that the correction data can be created with high accuracy. This can improve the accuracy of motor control.

It is a figure which shows the structure of the motor control apparatus used in order to acquire the knowledge used as the foundation of this invention, and the relationship between the dynamic real error detected by the said apparatus, and current ripple. It is a figure which shows the relationship between the static real error recognized in the apparatus shown to Fig.1 (a), and the dynamic real error at the time of forward rotation. It is a figure which shows the relationship between the static real error recognized in the apparatus shown to Fig.1 (a), and the dynamic real error at the time of reverse rotation. It is a figure which shows the relationship between a static real error, the dynamic actual error at the time of forward rotation, and the dynamic actual error at the time of reverse rotation. It is a figure which shows the electrical constitution of one Embodiment of the motor control apparatus concerning this invention. It is a flowchart which shows the correction data creation operation | movement in the motor control apparatus shown in FIG. It is a figure which shows the rotational speed pattern of the motor in correction data creation. It is a graph which shows an example of the current ripple of forward rotation and reverse rotation. It is a graph which shows an example of phase alignment operation. It is a graph which shows an example of similarity ratio matching operation. It is a graph which shows offset adjustment operation | movement. It is a graph which shows the improvement of a static real error by using correction data.

A. Similarity Relationship between Resolver Position Detection Error and Current Command The inventor of the present application conducted various experiments using the motor control device having the configuration shown in FIG. I gained the knowledge that a relationship exists. The motor control device 100 used in the experiment here is a robot controller, and the motor M is rotated by the motor control device 100. As shown in FIG. 1A, a reference position detector E capable of detecting a position with higher accuracy than the resolver Re is attached to the rotating shaft of the motor M. Detection signals from the resolver Re and the reference position detector E are output to the motor control device 100, respectively. In addition, the code | symbol PC in the figure (a) is a personal computer connected to the motor control apparatus 100 via the serial communication interface (RS232C).

  FIG. 1B is a diagram showing the relationship between the dynamic actual error and the current command when the resolver Re is used. This experimental result was sampled while rotating the motor M at a constant speed of 30 [rps]. The dynamic actual error in FIG. 5B means the difference between the detection position of the resolver measured in the constant speed operation state and the reference position detector. In this embodiment, the dynamic actual error is determined from the detection position of the resolver Re at each rotation angle. A value obtained by subtracting the detection position of the reference position detector E is used, and the position detection error of the resolver Re is indicated by this dynamic actual error. Further, the current command indicates the AC component of the current command value in the constant speed operation state, that is, the current ripple. In this embodiment, the current command signal sampled during one rotation interval is obtained, and the current interval is calculated. The current ripple is obtained by subtracting the above section average from the current command signal. The horizontal axis in FIG. 5B, that is, the rotation angle is obtained by converting the detection position of the reference position detector E into an angle.

  As is clear from FIG. 5B, the dynamic actual error, which is the position detection error of the resolver Re, has a similar relationship with the AC component (current ripple) of the current command value. Therefore, the inventor of the present application can estimate the dynamic actual error from the current ripple, create correction data from the estimation error, and improve the position accuracy by correcting the position detection signal of the resolver Re with the correction data. The knowledge that it was possible to get it. Further, the inventor of the present application measures a dynamic actual error while rotating the motor M at various constant speeds (15 [rps], 30 [rps], 60 [rps]), and uses the measurement result as a static actual error. Together with FIG. Further, the dynamic actual error when the motor M was rotated in the reverse direction was also measured, and the measurement results are summarized in FIG. 3 together with the static actual error. The “static actual error” means a difference between detection angles of the resolver Re and the reference position detector E measured in a stationary state.

  FIG. 2 is a diagram showing the relationship between the static actual error recognized in the apparatus shown in FIG. 1 (a) and the dynamic actual error during forward rotation. FIG. 3 is a diagram showing the relationship between the static actual error recognized in the apparatus shown in FIG. 1A and the dynamic actual error during reverse rotation. Further, FIG. 4 shows the relationship between the dynamic actual error during forward rotation, the dynamic actual error during reverse rotation, and the static actual error when the motor is reciprocated at the same constant speed in the apparatus shown in FIG. FIG. In these drawings, “still” indicates a static actual error that is a difference between detection angles of the resolver Re and the reference position detector E measured in a stationary state.

  At the time of forward rotation, as shown in FIG. 2, the phase is delayed as the speed increases, and the error on the (−) side is increased. On the other hand, at the time of reverse rotation, as shown in FIG. 3, since the rotation angle of the horizontal axis is scanned from 360 ° to 0 °, the phase is delayed as the speed increases, and the error on the (+) side is also increased. It has increased. One of the main reasons can be attributed to the RD converter built in the motor control device 100. This “RD converter” is a resolver-digital converter and has a function of converting the output signal of the resolver into digital angle data. Therefore, due to the delay system of the RD converter, it is considered that the error in the detection result of the resolver Re increases and the phase tends to be delayed with respect to the detection result of the reference position detector E without delay.

  Further, when the dynamic actual error when the motor M is rotated forward at a constant speed, for example, 60 [rps], the dynamic actual error when rotated reversely at the same speed, and the static actual error are plotted on the same graph, FIG. As shown in Fig. 3, the error increasing direction and the phase changing direction are opposite in the forward and reverse rotations, and the average of the dynamic actual error in the forward rotation and the dynamic actual error in the reverse rotation is the static actual error. Is approximate. That is, while the motor M is reciprocatingly driven at the same constant speed, the dynamic actual error at the time of forward rotation and the dynamic actual error at the time of reverse rotation are obtained, and the values are averaged for each rotation angle. The inventor of the present application has obtained the knowledge that the actual error can be approximately obtained. 2 to 4, only the measurement result of 15 to 60 [rps] is shown, but the same measurement result is obtained for 60 to 100 [rps], and the above knowledge is established.

  Based on such knowledge, the inventor of the present application uses a forward drive pattern including a constant speed region in which the rotation shaft of the motor M rotates forward at a constant speed and a return path drive pattern including a constant speed region in which the motor M rotates backward at the same speed. It was concluded that the correction data can be created with high accuracy from the dynamic actual error during forward rotation and the dynamic actual error during reverse rotation while the motor M is driven reciprocally. Hereinafter, an embodiment of the invention for creating correction data using the above knowledge will be described with reference to FIGS.

B. Embodiment FIG. 5 is a diagram showing an electrical configuration of an embodiment of a motor control device according to the present invention. The motor control device 1 includes a motor drive unit 2 that drives a motor M based on a position command signal, and a correction data creation unit 3 that creates correction data. In the following, the configuration of the correction data creation unit 3 will be described after the configuration of the motor drive unit 2 is described first.

  In the motor drive unit 2, the position control unit 21 outputs a speed command signal based on a difference between a position command signal given from the outside and a corrected position signal described later. The speed control unit 22 outputs a current command signal based on the difference between the driving speed of the motor M calculated by differentiating the corrected position signal with the differentiator 23 and the speed command signal. This current command signal is output to the correction data creation unit 3 described later and also to the current control unit 24. The current control unit 24 outputs a drive command signal to the motor M via the current sensor 25 based on the current command signal. More specifically, the current sensor 25 detects the drive command signal output from the current control unit 24 and feeds back a current detection signal indicating the current value of the drive command signal to the input side of the current control unit 24. Then, the current control unit 24 outputs a drive command signal based on the difference between the current detection signal and the current command signal. And the motor M which received the drive command signal outputs the torque according to this drive command signal.

  In addition, a resolver Re is connected to the rotation shaft (not shown) of the motor M, and the rotation position of the rotation shaft is detected and an analog signal indicating the rotation position is output. This analog signal is input to the RD converter 26, converted into a digital position detection signal, and output. A signal corrected by adding a correction signal generated by the correction data generating unit 3 described below to the position detection signal is the corrected position signal. As described above, the position control unit 21 and the differentiator 23 receive the corrected signal. Given.

  Next, after describing the configuration of the correction data creation unit 3, a method for creating correction data will be described. The correction data creation unit 3 includes an arithmetic processing unit 31 having an arithmetic function such as a CPU (Central Processing Unit) and a storage unit 32 having four memories 321 to 324. The arithmetic processing unit 31 samples a current command signal output from the speed control unit 22 in accordance with a program stored in advance while the motor M is reciprocatingly driven by the motor driving unit 2 with a predetermined driving pattern. Next, correction data is created by executing phase alignment processing, similarity ratio alignment processing, and offset alignment processing, which will be described in detail below. As described above, in this embodiment, the arithmetic processing unit 31 functions as the current command value sampling unit 311, the phase matching unit 312, the similarity ratio matching unit 313, and the offset matching unit 314.

  FIG. 6 is a flowchart showing a correction data creation operation in the motor control device shown in FIG. In the present embodiment, when the motor M or the resolver Re is attached or exchanged or when the creation of correction data is instructed by the user, the motor M is incorporated in the apparatus, for example, the motor M is driven by the robot. When used as a source, correction data creation processing described below is executed while the movable part of the robot (moving mechanism part such as a ball screw) is connected to the rotation axis of the motor M.

  In step S1, the distance for moving the robot by operating the motor M by the motor driving unit 2 and the speeds V0 + and V0− (where | V0 + | = | V0− |) in the constant speed region are set. With these settings, when the correction data creation process is performed, the motor M drives the robot and the operation pattern in which the robot operates, that is, the motor M drive pattern by the motor driving unit 2 is determined. In addition, a plurality of operation modes are prepared in advance as the operation mode of the motor drive unit 2, but in the correction data creation process, a correction signal is not first output to the motor drive unit 2, that is, correction by correction data is performed. “No correction operation” for driving the motor M is selected (step S2), and the phase matching process is executed (steps S3 to S6).

  In this phase matching process, the motor M is started to be driven by the motor drive unit 2 to reciprocate the robot, and current sampling is performed during the movement (step S3). In other words, when the motor M starts to be driven, as shown in FIG. 7, for example, the motor M rotates forward, and the moving speed of the robot is accelerated to the speed V0 + over a predetermined time, according to the moving distance set in step S1. After maintaining the constant speed V0 + for the time, deceleration is started and the forward rotation of the motor M is stopped. In this way, moving the robot by rotating the motor M forward is referred to as “outward movement”, and the drive pattern of the motor M for such movement is referred to as “outward drive pattern” and the forward drive pattern. A region where the constant speed V0 + is maintained in is referred to as a “constant speed region”. In addition, the current command signal output from the speed control unit 22 of the motor drive unit 2 during one rotation of the motor M is sampled at regular time intervals at approximately the intermediate position of the constant speed region during the forward movement. Is written in the current sampling memory 321 as “positive rotation sampling data”.

  When the forward movement of the robot is completed, the motor M rotates in the reverse direction and moves the robot with a drive pattern obtained by inverting the forward drive pattern. That is, the moving speed of the robot is accelerated to the speed V0−, and after maintaining the constant speed V0− for the time according to the moving distance set in step S1, the deceleration is started and the reverse rotation of the motor M is stopped. The movement of the robot by reversely rotating the motor M in this way is referred to as “return movement”, and the drive pattern of the motor M for such movement is referred to as “return path drive pattern”. An area where the constant speed V0− is maintained is also referred to as a “constant speed area”. In addition, the current command signal output from the speed control unit 22 of the motor drive unit 2 during one rotation of the motor M is sampled at a constant time interval at each intermediate rotation angle at a substantially intermediate position in the constant speed region during the backward movement. Is written in the current sampling memory 321 as “reverse rotation sampling data”.

  In the next step S4, normal rotation sampling data is read from the current sampling memory 321, and an average value of current command values for one rotation is calculated. Then, for each rotation angle, the average value is subtracted from the current command value to obtain a positive rotation current ripple, and the current sampling memory 321 is overwritten. Thus, a positive rotation current ripple that is an AC component of the current command value during the forward movement is acquired (solid line in FIG. 8).

  On the reverse rotation side, the reverse rotation current ripple is obtained in the same manner as the normal rotation side (step S5). That is, the reverse rotation sampling data is read from the current sampling memory 321, the average value of the current command value for one rotation is calculated, and the normal rotation current ripple is obtained by subtracting the average value from the current command value for each rotation angle, The current sampling memory 321 is overwritten. Thus, the reverse rotation current ripple which is the AC component of the current command value during the backward movement is acquired (dotted line in FIG. 8).

  When the normal rotation current ripple and the reverse rotation current ripple are obtained, the normal rotation current ripple and the reverse rotation current ripple are read from the current sampling memory 321 for each rotation angle, and the average value of these values is calculated. Then, the average value (= (forward rotation current ripple + reverse rotation current ripple) / 2) is written as an average current ripple in the correction source table in the memory 322 (step S6). In FIG. 9, an example of the average current ripple obtained as described above is indicated by a broken line in FIG.

  When the above phase matching process is completed (timing T1 in FIG. 7), “similarity matching operation” is selected as the operation mode (step S7), and the similarity ratio matching process described below is executed (steps S8 to S8). S16). In this similarity ratio matching process, various initial settings are performed in step S8. In the present embodiment, as one of the initial settings, a value obtained by subtracting the minimum value from the maximum value of the average current ripple for one rotation, that is, the minimum value RWmin of the current ripple amplitude is a default value (in this embodiment, “10000”). And “1” is set as the initial value of the count value n. In the next step S9, the similarity ratio is set to a value (n / 20). For example, when n = 1, the similarity ratio is set to an initial value (1/20).

  After setting the similarity ratio (n / 20), the average current ripple is read from the correction source table memory 322, and a value obtained by multiplying the similarity ratio by the average current ripple for each rotation angle is output to the motor drive unit 2 as a correction signal. Then, while performing correction using the correction signal, the motor driving unit 2 starts driving the motor M to reciprocate the robot, and current sampling is performed during the movement (step S10). The reciprocating movement operation and the current sampling operation are the same as those in the phase matching process (step S3) except that the correction signal is used for correction, and positive rotation sampling data for one rotation and one rotation. The reverse rotation sampling data is written in the current sampling memory 321. For example, when n = 1, while driving the motor M with the continuous forward drive pattern and the backward drive pattern from the timing T1 to the timing T2 in FIG. Sampling is performed.

  When the current sampling is completed, the current ripple is calculated and written into the similarity ratio matching memory 323 (step S11). That is, the forward rotation current ripple is calculated in the same manner as in step S4, the reverse rotation current ripple is calculated in the same manner as in step S5, and the average current ripple is calculated in the same manner as in step S6. Then, the average current ripple when the similarity ratio is set to (n / 20) is written to the similarity ratio matching memory 323.

  In the next step S12, after obtaining the current ripple amplitude from the average current ripple for one rotation written in the similarity comparison memory 323, it is determined whether or not the current ripple amplitude is less than the minimum value RWmin. Then, when “YES” is determined in step S12, that is, when it is determined that the current ripple amplitude at the count value n is less than the minimum value RWmin, the minimum value RWmin is updated to the current ripple amplitude and the count value n is optimized. After the value Kbest is written in the similarity ratio matching memory 323 (step S13), the process proceeds to step S14. Note that the storage destination of the optimum value Kbest is not limited to the similarity comparison memory 323, and can be written to an arbitrary memory. On the other hand, if “NO” is determined in the step S12, the minimum value RWmin and the optimum value Kbest are not updated, and the process directly proceeds to a step S14.

  After the count value n is incremented by “1” in step S14, it is determined whether or not the count value n is “21” (step S15). Then, while it is determined as “NO” in step S15, that is, the count value n is “20” or less, the process returns to step S9 to repeat the similarity ratio derivation process (steps S9 to S15) that minimizes the current ripple amplitude. . That is, in the present embodiment, (1/20), (2/20),..., (20/20) are prepared as candidates for similarity ratio, and the similarity ratio derivation process is performed for each similarity ratio candidate. In addition, the optimum value Kbest is determined.

  On the other hand, when “YES” is determined in step S15, the optimum value Kbest is read from the similarity ratio matching memory 323, and the optimum similarity ratio (= Kbest / 20) at which the current ripple amplitude is minimized is determined. Then, the average current ripple is read from the correction source table memory 322, and a value obtained by multiplying the average current ripple for each rotation angle by the optimum similarity ratio is written in the correction table memory 324 as similarity ratio completed data (step S16).

  In this way, by adjusting the average current ripple with the optimum similarity ratio, similar ratio-matched data (solid line in FIG. 10) approximated to the static actual error (dotted line in FIG. 10) is obtained. For example, as shown in FIG. In this embodiment, the similarity ratio-matched data is offset from the static actual error, and the static actual error when the rotation angle is 0 ° is zero as shown by the dotted line in FIG. Finally, offset adjustment is performed (step S17). That is, the similarity-matched data with the rotation angle of zero is subtracted from the similarity-matched data for each rotation angle, and the offset-matched data is used as final correction data (for example, a solid line in FIG. 11) to the correction table memory 324 Overwrite to. Thereby, more accurate correction data can be obtained.

  As described above, according to the present embodiment, correction data used in the motor control device 1 is created based on the knowledge described in the section “A. Similarity between position detection error of resolver and current command”. Therefore, the correction data can be created with high accuracy, and the control accuracy of the motor M can be improved.

  In addition, as a method for creating correction data, a method has been proposed in which a reference position detector is attached and an error from a position measured by the reference position detector is used as correction data. A correction facility for preparation is separately required. On the other hand, in the said embodiment, correction data can be created by the original function of the motor control apparatus 1 without using the said correction equipment at all, and own performance can be improved. That is, the motor control device 1 according to the above embodiment has a self-correction function. Further, the correction data can be created with the motor M attached to the robot. Therefore, even when the motor M is replaced or repaired at a factory or the like where the robot is installed, correction data can be created after replacement and repair on the spot.

  Further, in the above embodiment, the correction data is created using the current command signal after the speed command signal is amplified by the speed control unit 22, and the resolution can be sufficiently high, and the corrected position accuracy is achieved by the prior art. Than can be raised. Here, the correction data may be created using the current detection signal instead of the current command signal, and the same effect as the above embodiment can be obtained.

  Thus, in the present embodiment, the resolver Re corresponds to an example of the “sensor” of the present invention. Further, “forward rotation current ripple” corresponds to an example of “forward rotation command information” of the present invention, and “reverse rotation current ripple” corresponds to an example of “reverse rotation command information” of the present invention. Further, the average current ripple obtained in step S6 corresponds to “phase alignment information” of the present invention. The sampling of the current command signal executed during one forward movement corresponds to an example of “sampling during forward rotation” of the present invention, and the sampling of the current command signal executed during one backward movement is performed according to the present invention. Is an example of “sampling during reverse rotation”, and the operation of continuously performing these corresponds to an example of “a pair of sampling operations” of the present invention. Correction data is created by repeating n + 1) times. In the present embodiment, as shown in FIG. 7, the pair of sampling operations are repeated 20 times while switching the similarity ratio candidates during the similarity ratio matching process, but the number of repetitions (number of similarity ratio candidates) is It is not limited to this, and is arbitrary.

C. Others The present invention is not limited to the above-described embodiment, and various modifications can be made to the above-described one without departing from the gist thereof. For example, in the above embodiment, the present invention is applied to the motor control device 1 that controls the motor M using a signal output from the resolver Re. However, the present invention is applicable to position detection sensors other than the resolver Re, such as an encoder. The present invention can also be applied to a motor control device used as a “sensor”.

  In the above embodiment, the sampling period of the current command signal is one rotation of the motor M, but may be sampled exceeding one rotation. For example, when the current command signal for m rotations is sampled, m sampling data may be averaged for each rotation angle to derive “forward rotation current ripple” or “reverse rotation current ripple”.

  In the above embodiment, the average current ripple is obtained by averaging the forward rotation current ripple and the reverse rotation current ripple. However, the sampling data during the forward rotation and the sampling data during the reverse rotation are averaged. An average current ripple may be obtained. That is, the step of removing the direct current component may be omitted, and the phase matching information may be obtained from both sampling data, thereby simplifying the signal processing.

  In the above-described embodiment, in the phase matching process and the similarity ratio matching process, current sampling is performed while driving the motor with the same drive pattern. However, it is not essential to match the drive patterns. In the phase matching process, it is desirable to perform current sampling at a speed that is less affected by rotational friction of a speed reducer (not shown) connected to the rotating shaft of the motor and has high similarity to the position detection error of the resolver. On the other hand, in the similarity ratio matching process, it is desirable to perform current sampling at a speed that is not affected by the rotational friction and that greatly shows the effect of the correction. Therefore, in order to satisfy such a demand, the drive pattern is set so that the absolute values of the velocities V0 + and V0− in the constant speed region in the phase matching process are larger than those in the similarity ratio matching process. Is preferred.

  Furthermore, although the case where the motor M is used as a driving source of the robot has been described in the above embodiment, the application target of the present invention is not limited to the technique for controlling the motor attached to the robot. That is, the present invention can also be applied to a motor control device that controls a motor attached to an industrial device such as a surface mounter, a component inspection device, or a semiconductor manufacturing device, in which a movable part is driven by a motor.

  The present invention can be applied to a correction data generation technique for generating correction data for correcting a signal output from a sensor connected to a rotating shaft of a motor and a motor control technique for controlling a motor using the correction data. It is.

DESCRIPTION OF SYMBOLS 1 ... Motor control apparatus 3 ... Correction data creation part 31 ... Operation processing part M ... Motor Re ... Resolver

Claims (16)

A position detection signal related to the rotation position of the rotation shaft is generated based on a signal output from the sensor in accordance with the rotation angle of the rotation shaft of the motor that rotates in accordance with the command signal, and the position detection signal is corrected. A correction data creating method for creating the correction data in a motor control device that controls the motor by feeding back a corrected position signal obtained by correcting in
While the motor is driven in an outward drive pattern including a constant speed region in which the rotating shaft rotates normally at a constant speed, the command signal is sampled while the rotating shaft rotates positively one or more times in the constant speed region. Get command information during rotation,
The command signal is sampled while the motor is driven in a backward drive pattern including a constant speed region in which the rotating shaft reversely rotates at the constant speed while the rotating shaft reversely rotates one or more times in the constant speed region. Obtain the reverse rotation command information obtained,
A correction data creation method, wherein the correction data is created using the forward rotation command information and the reverse rotation command information. The correction data creation method according to claim 1,
The correction data creation method in which the sampling at the time of forward rotation and the sampling at the time of reverse rotation are both performed N (where N is a natural number of 2 or more). The correction data creation method according to claim 2,
A correction data generation method in which a pair of sampling operations for performing sampling at the time of forward rotation and sampling at the time of reverse rotation are repeated N times. The correction data creation method according to claim 3,
A correction data creation method for determining the correction data after repeating the pair of sampling operations N times. A correction data creation method according to any one of claims 1 to 4,
The correction signal generation method, wherein the command signal is a signal related to a current applied to the motor, and the forward rotation command information and the reverse rotation command information are current command values for each rotation angle of the rotating shaft. A correction data creation method according to any one of claims 1 to 4,
The command signal is a signal related to the current applied to the motor, and the forward rotation command information and the reverse rotation command information are current detection signals of the motor for each rotation angle of the rotating shaft. . The correction data creation method according to claim 5 or 6,
A method of creating correction data in which sampling of the command signal is performed for each rotation angle of the rotating shaft. The correction data creation method according to claim 7,
The position detection signal is fed back without being corrected with the correction data to drive the motor back and forth, and a DC component is removed from the forward rotation command information acquired during the forward drive, and a positive rotation current ripple is obtained. The reverse rotation current ripple is obtained by removing the DC component from the reverse rotation command information acquired during the backward drive, and the average of the forward rotation current ripple and the reverse rotation current ripple is calculated for each rotation angle of the rotating shaft. A first step for obtaining an average current ripple for each rotation angle obtained as phase alignment information;
And a second step of obtaining the correction data from the phase alignment information. The correction data creation method according to claim 7,
The position detection signal is fed back without being corrected by the correction data, and the motor is reciprocally driven. The forward rotation command information acquired during the forward drive and the reverse rotation command acquired during the backward drive. A first step of obtaining, as phase matching information, an average current ripple for each rotation angle obtained by calculating an average with the information for each rotation angle of the rotation shaft;
And a second step of obtaining the correction data from the phase alignment information. The correction data creation method according to claim 8 or 9,
In the second step, a correction data creation method for obtaining the correction data based on the similarity ratio-adjusted data for each rotation angle obtained by multiplying the similarity ratio by the average current ripple for each rotation angle constituting the phase alignment information . The correction data creation method according to claim 10,
A plurality of different similarity ratio candidate values are prepared as candidates for the similarity ratio,
For each similarity ratio candidate value, the motor is reciprocated by feeding back a corrected position signal obtained by correcting the position detection signal based on data obtained by multiplying the similarity ratio candidate value by the phase matching information. In addition, the DC component is removed from the forward rotation command information acquired during the forward drive to obtain the positive rotation current ripple, and the DC component is removed from the reverse rotation command information acquired during the backward drive A ripple is obtained, and the difference between the maximum value and the minimum value of the average current ripple for each rotation angle obtained by calculating the average of the forward rotation current ripple and the reverse rotation current ripple for each rotation angle of the rotation shaft is determined as a current ripple. Calculated as amplitude,
A correction data creation method for setting a similarity ratio candidate value that is a minimum value among the plurality of current ripple amplitudes as the similarity ratio. The correction data creation method according to claim 10,
A plurality of different similarity ratio candidate values are prepared as candidates for the similarity ratio,
For each similarity ratio candidate value, the motor is reciprocated by feeding back a corrected position signal obtained by correcting the position detection signal based on data obtained by multiplying the similarity ratio candidate value by the phase matching information. For each rotation angle obtained by calculating the average of the forward rotation command information acquired during the forward drive and the reverse rotation command information acquired during the backward drive for each rotation angle of the rotary shaft. The difference between the maximum and minimum values of the average current ripple is calculated as the current ripple amplitude.
A correction data creation method for setting a similarity ratio candidate value that is a minimum value among the plurality of current ripple amplitudes as the similarity ratio. The correction data creation method according to any one of claims 10 to 12,
In the second step, the similarity ratio-matched data in which the rotation angle is zero among the similarity ratio-matched data for each rotation angle of the rotating shaft is set as offset data, and the offset from the similarity ratio-matched data for each rotation angle A correction data creation method in which offset-adjusted data obtained by subtracting data is used as the correction data. The correction data creation method according to any one of claims 8 to 13,
The correction data creation method in which the absolute value of the constant speed in the first step is larger than the absolute value of the constant speed in the second step. The correction data creation method according to any one of claims 1 to 14,
The sensor is a resolver;
The correction data creation method, wherein the constant speed is 15 [rps] to 100 [rps]. A position detection signal related to the rotation position of the rotation shaft is generated based on a signal output from the sensor in accordance with the rotation angle of the rotation shaft of the motor that rotates in accordance with the command signal, and the position detection signal is corrected. A motor control device for controlling the motor by feeding back a corrected position signal obtained by correction in
A correction data creation unit for creating the correction data;
When creating the correction data,
The motor driving unit includes a forward drive for driving the motor in an outward drive pattern including a constant speed region in which the rotating shaft is normally rotated at a constant speed, and a constant speed region in which the rotational shaft is reversely rotated at the constant speed. Performing a return path drive for driving the motor in a return path drive pattern;
The correction data creation unit acquires the command information at the time of forward rotation by sampling the command signal while the rotary shaft is rotated forward by one or more rotations in the constant speed region during the forward drive, and during the backward drive. The reverse rotation command information obtained by sampling the command signal while the rotation shaft rotates reversely by one rotation or more in the constant speed region is acquired, and the forward rotation command information and the reverse rotation command information are used. And generating the correction data.

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