JP6479256B2 - Motor control device and motor device using the same - Google Patents

Description

  The present invention relates to a motor control device for measuring backlash and a motor device using the same.

  A transmission mechanism that transmits power using a transmission unit such as a screw or a gear is provided with a backlash so that the gears can move freely, for example. Here, the backlash is a gap between teeth when a pair of gears are engaged. Backlash increases due to wear caused by use, and may cause vibration, deterioration of accuracy, decrease in strength, failure, and the like. Accordingly, there is a need for a motor control device that can measure the backlash to determine the degree of wear of the transmission mechanism and estimate the life and deterioration of the transmission mechanism.

  Patent Document 1 acquires the rotation state of a drive shaft of a motor using a position signal from a position detector, acquires the rotation state of a load shaft on a load side using a position signal from the position detector, and drives the drive shaft. Disclosed is a motor control device that measures the backlash of a transmission mechanism based on the rotational state of the motor and the rotational state of a load shaft. Specifically, the backlash of the transmission mechanism is estimated by measuring the power transmission accuracy of the transmission mechanism from the drive shaft to the load shaft by driving the drive shaft in the forward direction with a drive device such as a motor and then rotating in the reverse direction. To do.

  Patent Document 2 discloses a motor control device that measures the backlash of a transmission mechanism by using inputs from a position detector that detects a rotation state of a drive shaft of a motor and a torque sensor that measures torque applied to the drive shaft. Is disclosed. Specifically, the position of the drive shaft from the start of reverse rotation drive to the sudden increase in torque when the drive shaft is driven forward rotation beyond the assumed backlash magnitude and then reversely driven beyond the assumed maximum backlash. Backlash is calculated from the amount of signal change. Here, the mechanical contact inside the transmission mechanism when the drive shaft is reversely driven by an angle corresponding to backlash is determined by a torque sensor.

Japanese Patent Laid-Open No. 7-181107 JP2012-149919A

  However, in the prior art, in order to measure the backlash, the position signal from the position detector that detects the rotation state of both the load shaft and the drive shaft, or the position detector and the drive that detect the rotation state of the motor drive shaft. A signal from a torque sensor that measures the torque applied to the shaft was required. As a result, there is a problem that the device configuration to which the motor control device can be connected is limited.

  The present invention has been made in view of the circumstances as described above, and it is possible to measure the backlash of the transmission mechanism as long as the position signal from the position detector that detects the rotation state of the drive shaft of the motor can be acquired. The object is to provide a device.

  The motor control device according to the present invention includes a drive command generator that generates a drive command that reversely drives the motor in a direction opposite to the one direction after the motor is normally driven in one direction, and the drive command and the motor operation A torque command generator for generating a torque command for driving the motor based on the position signal indicating the state, a drive side transmission unit connected to the motor and a load using the signal calculated based on the position signal A contact detector that detects a contact between the connected load side transmission unit as a measurement completion contact and outputs the detection result as a contact signal, and between the drive side transmission unit and the load side transmission unit based on the contact signal and the position signal. A backlash estimator that estimates the backlash of

  In the motor control device according to the present invention, the backlash of the transmission mechanism can be measured as long as the position signal from the position detector that detects the rotational state of the drive shaft of the motor can be acquired. Thereby, it can connect to the apparatus of a wider structure.

It is a block diagram for demonstrating the motor apparatus which concerns on Embodiment 1 of this invention. It is the figure which showed the internal structure of a transmission mechanism, and the measurement process of the backlash by forward rotation drive and reverse rotation drive. It is the figure which showed an example of the time-sequential waveform at the time of reverse drive of the motor control apparatus which concerns on Embodiment 1 of this invention. It is the figure which showed an example of the time series waveform when the acceleration command value in drive command Cd is made constant. It is the figure which showed an example of the time series waveform when the speed command value in drive command Cd is made constant. It is a block diagram for demonstrating the motor apparatus which concerns on Embodiment 2 of this invention. It is the figure which showed an example of the time-sequential waveform at the time of reverse drive of the motor control apparatus which concerns on Embodiment 2 of this invention. It is a block diagram for demonstrating the motor apparatus which concerns on Embodiment 3 of this invention. It is the figure which showed an example of the time-sequential waveform at the time of reverse drive of the motor control apparatus which concerns on Embodiment 3 of this invention. It is a block diagram for demonstrating the motor apparatus which concerns on Embodiment 4 of this invention. It is the figure which showed an example of the time-sequential waveform at the time of reverse rotation drive of the motor control apparatus which concerns on Embodiment 4 of this invention. It is a block diagram for demonstrating the motor apparatus which concerns on Embodiment 5 of this invention. It is a block diagram for demonstrating the motor apparatus which concerns on Embodiment 6 of this invention. It is a flowchart showing the backlash measurement procedure which concerns on Embodiment 6 of this invention. It is the figure which showed the drive direction at the time of the backlash estimation operation | movement in which the load shaft of the transmission mechanism of the motor control apparatus which concerns on Embodiment 6 of this invention receives external force, and rotates. It is the figure which showed an example of the time-sequential waveform when the motor control apparatus which concerns on Embodiment 6 of this invention produced | generated the drive command which performs the test drive of multiple times. It is the figure which showed the internal structure of the transmission mechanism of the motor apparatus which concerns on Embodiment 6 of this invention, and the measurement process of a backlash. It is a figure for demonstrating the estimated load shaft position which concerns on Embodiment 6 of this invention. It is a block diagram for demonstrating the motor apparatus which concerns on Embodiment 7 of this invention. It is a block diagram for demonstrating the motor apparatus which concerns on Embodiment 8 of this invention. It is the figure which showed an example of the time-sequential waveform at the time of reverse drive of the motor control apparatus which concerns on Embodiment 8 of this invention.

  Embodiments of a motor control device according to the present invention will be described below with reference to FIGS. It should be noted that the present invention is not limited to the following embodiments, and it goes without saying that the embodiments may be appropriately changed or combined appropriately. In the following embodiments, a rotary motor that generates torque as a driving force is described as an example. However, the present invention also relates to a device that generates a linear thrust as a driving force, such as a linear motor. The motor control device can be similarly applied.

Embodiment 1 FIG.
FIG. 1 is a block diagram for explaining a motor device according to Embodiment 1 of the present invention. The motor device includes a motor control device 1, a motor 2, a position detector 3 that detects a rotation state (operation state) of a drive shaft of the motor 2, and a transmission mechanism 100.

  The motor 2 is controlled and driven by the motor control device 1. The transmission mechanism 100 transmits the torque of the motor 2 to the load 4, is connected to the motor 2 via the drive shaft 101, and is connected to the load 4 via the load shaft 102. The position detector 3 detects the rotation state of the drive shaft of the motor 2 and outputs it as a position signal Sp. The position detector 3 is a rotary encoder, for example. In the present embodiment, the position detector 3 and the motor control device 1 are configured separately, but the motor control device 1 may include the position detector 3. A speed sensor or an acceleration sensor may be used instead of the rotary encoder.

  The motor control device 1 includes a drive command generator 10, a torque command generator 11, a current controller 12, a contact detector 13, and a backlash estimator 14. The drive command generator 10 outputs a drive command Cd to the torque command generator 11. The torque command generator 11 first generates a torque command Ct using the position signal Sp and the drive command Cd so that the position signal Sp output from the position detector 3 follows the drive command Cd. Further, this torque command Ct is output to the current controller 12 and the contact detector 13. The current controller 12 outputs a current Im corresponding to the torque command Ct to the motor 2.

  The contact detector 13 detects contact in the transmission mechanism 100 using the input torque command Ct, and outputs a detection result as a contact signal Sc. The backlash estimator 14 estimates the backlash in the transmission mechanism 100 using the contact signal Sc and the position signal Sp.

  Here, the configuration of the transmission mechanism 100 will be described with reference to FIG. FIG. 2 is a diagram illustrating an internal structure of the transmission mechanism 100 of the motor device according to the first embodiment and a backlash measurement process by forward drive and reverse drive. FIGS. 2A, 2B, and 2C show the state of the gear before measuring the backlash, the state of the gear that is driven in the forward direction, and the state of the gear that is driven in the reverse direction, respectively. In the present embodiment, the counterclockwise direction indicated by the arrow (b) in the figure is the forward rotation direction, and the clockwise direction indicated by the arrow (c) is the reverse rotation direction. Needless to say, the direction of the reverse rotation direction may be changed. Hereinafter, driving by the rotary motor corresponds to “forward rotation driving” and “reverse rotation driving”. Further, driving by a rotary motor or linear motor corresponds to “forward driving” and “reverse driving”.

  The drive shaft 101 is a drive rotation shaft of the motor 2, and a drive side gear (drive side transmission unit) 101 a is attached to the drive shaft 101. The load shaft 102 is a driven rotary shaft for transmitting torque from the drive shaft 101 to the load 4 via the transmission mechanism 100. A load side gear (load side transmission portion) 102 a is attached to the load shaft 102. In the transmission mechanism 100, the torque of the motor 2 is transmitted to the load 4 by the drive side gear 101 a and the load side gear 102 a meshing with each other.

  In addition, although the reduction mechanism provided with two gears is mentioned as an example as the transmission mechanism 100 of the present embodiment, a transmission mechanism having three or more gears may be used. Further, instead of the two gears, a rack and pinion, a ball screw, or the like may be used. The drive side gear 101a and the load side gear 102a may be referred to as both gears.

  Next, in the present embodiment, an operation procedure of the motor control device 1 that measures the backlash of the transmission mechanism 100 by forward rotation and reverse rotation of the motor 2 will be described.

  In the present embodiment, backlash will be described below as meaning angular backlash. Here, the angle backlash is a maximum value of an angle at which one gear can move when one gear is fixed. The angle θ between the dotted lines shown in FIG. 2C is the backlash. Therefore, from the state shown in FIG. 2B to the state shown in FIG. 2C, the backlash can be measured from the angle at which the drive shaft 101 rotates, that is, the amount of change in the position signal Sp. Instead of the angle backlash, different types of backlash such as a normal backlash and a circumferential backlash may be used.

  Hereinafter, the time from the state shown in FIG. 2B to the state shown in FIG. 2C is referred to as a contact required time Tc. Further, the amount of change in the position signal Sp of the motor 2 during the required contact time Tc is referred to as a contact position displacement Pc. Furthermore, when measuring the backlash, there are two cases of contact between the drive side gear 101a and the load side gear 102a, and the following description will be given separately. “Contact before measurement” means that both gears 101a and 102a are in the state shown in FIG. 2B in order to start measurement of backlash. More specifically, it is assumed that the drive side gear 101a and the load side gear 102a come into contact with each other by driving the drive shaft 101 in the normal direction in one direction. “Measurement completion contact” means that the state shown in FIG. 2C is reached, and is contact by reverse rotation driving. More specifically, after both the gears 101a and 102a are “contact before measurement”, the motor 2 drives the drive shaft 101 in the reverse direction in the opposite direction to the one direction so that the drive side gear 101a and the load side gear are driven. 102a is in contact.

  As shown in FIG. 2A, the two gears 101a and 102a are not always in mechanical contact with each other at the start of forward rotation driving. Therefore, first, the motor 2 rotates the drive shaft 101 counterclockwise by the drive command Cd in the forward direction indicated by the arrow in the figure generated by the drive command generator 10, so that the drive side gear 101a is driven forward. . The drive command Cd includes, for example, parameters such as a position command value, a speed command value, and an acceleration command value for the motor 2. As shown in FIG. 2B, the two gears 101a and 102a come into contact before measurement by being driven forward.

  Here, an example of a method of detecting the reverse drive start time will be described. The acceleration command value and the speed command value in the drive command Cd are decelerated and stopped when both the gears 101a and 102a come into contact with each other due to the frictional force generated between the load shaft 102 and the bearing supporting the load shaft 102. Is adjusted. Thus, the backlash estimator 14 detects the reverse drive start time from the position signal Sp. For example, after the backlash estimator 14 detects the state in which the position signal Sp does not change, that is, the stop state of the motor 2 for a preset time, the backlash estimator 14 further changes the position signal Sp in the direction opposite to that immediately before the stop state of the motor 2. If detected, the detected time is set as the reverse drive start time. Instead of determining the reverse drive start time from the position signal Sp, the drive command Cd is input to the backlash estimator 14, and the backlash estimator 14 uses the drive command Cd to set the reverse drive start time. You may make it judge.

  Next, when the drive shaft 101 is driven in reverse, both the gears 101a and 102a are in contact with each other as shown in FIG. 2C on the surface opposite to the pre-measurement contact shown in FIG. This measurement completion contact is detected by the contact detector 13, and the detection result is output as a contact signal Sc. When the contact signal Sc is represented by a voltage, for example, the non-contact state is set to a voltage of 0V, and the contact state is output as a voltage different from 0V, for example, a voltage of 2V.

  When both gears 101 a and 102 a come into contact with each other due to the rotation of the drive shaft 101, the moment of inertia driven by the motor 2 increases, and a large torque is required for driving the motor 2. For this reason, the torque command generator 11 increases the torque command Ct necessary for the position signal Sp to follow the drive command Cd in the direction in which the torque signal Ct is driven in the reverse direction (the direction corresponding to the reverse drive). The contact detector 13 detects an increase in the torque command Ct and detects a measurement completion contact of the transmission mechanism 100.

  In order to reliably generate the pre-measurement contact and the measurement completion contact, the drive command Cd for forward rotation and reverse rotation larger than the actual backlash of the transmission mechanism 100 is required. Therefore, the maximum backlash allowed (maximum backlash allowable amount) is determined in advance, and the drive command generator 10 generates a drive command Cd that drives the drive shaft 101 sufficiently larger than the angle corresponding to the maximum backlash allowed. May be.

  FIG. 3 is a diagram illustrating an example of a time-series waveform when the motor control device 1 according to the first embodiment is driven in reverse rotation. That is, the horizontal axis is time in (a) to (d) in the figure. On the vertical axis, (a) shows the torque command Ct, (b) shows the amount of change per unit time of the torque command Ct, (c) shows the position signal Sp, and (d) shows the contact signal Sc.

  When the position signal Sp changes by an angle corresponding to backlash, both gears 101a and 102a come into contact with each other. Here, since the torque command Ct temporarily increases (or decreases), a peak A1 shown in FIG. Since the time differential value indicating the change in the torque command Ct also temporarily increases (or decreases), the peak B1 shown in FIG. 3B appears. A change amount C of the position signal Sp shown in FIG. 3C is a change amount of the position signal Sp in the required contact time Tc, and corresponds to backlash.

  An example of a method for detecting a measurement completion contact by the contact detector 13 will be described. When the amount of change per unit time of the torque command Ct exceeds a preset threshold value in the direction of reverse rotation driving (direction corresponding to reverse rotation driving), the contact detector 13 detects the measurement completion contact, A contact signal Sc indicating the contact state of both gears 101 a and 102 a is output to the backlash estimator 14. Here, the preset threshold value is, for example, a broken line b1 in FIG. Note that the contact detector 13 determines the measurement completion contact when the torque command Ct exceeds the preset threshold value (broken line a1) in the reverse drive direction instead of the change amount per unit time of the torque command Ct. It may be assumed that it has been detected. In other words, the contact detector 13 detects the measurement completion contact when the torque command Ct or the change amount per unit time of the torque command Ct exceeds the preset threshold value in the direction of reverse driving. . Further, as a method for determining the threshold value, for example, it may be set dynamically based on the torque command Ct. Note that the direction of reverse rotation driving (the direction corresponding to reverse rotation driving) in the torque command Ct and the change amount of the torque command Ct is a negative direction in FIGS. 3A and 3B, for example.

  In FIG. 3D, T1 indicates a period during which the drive shaft 101 is driven in reverse rotation (hereinafter referred to as “reverse rotation drive period”). T2 is a non-contact state in which both gears 101a and 102a are not in contact (hereinafter referred to as “non-contact period”). During this time, only the drive-side gear 101a rotates and the load-side gear is rotated. 102a is stopped. On the other hand, the contact period T3 is a period of contact state in which both gears 101a and 102a are in contact (hereinafter referred to as “contact period”). In the contact period T3, the load side gear 102a rotates together with the drive side gear 101a. doing. The point at which the non-contact period T2 switches to the contact period T3 is the start time of the measurement completion contact. During the contact period T3, the drive side gear 101a drives the load side gear 102a. Since the two gears 101a and 102a are separated after the lapse of time, the contact signal Sc indicates a non-contact state. Further, the non-contact period T2 is also the above-described required contact time Tc.

  Here, a backlash estimation method by the backlash estimator 14 will be described. A contact signal Sc (FIG. 3 (d)) is generated by the contact detector 13 based on the torque command Ct shown in FIGS. 3 (a) and 3 (b) or the value of the change amount of the torque command Ct. The backlash estimator 14 first obtains a non-contact period (required contact time Tc) T2 from the start of reverse rotation drive until the contact signal Sc rises. Next, as shown in FIG. 3C, a change amount C of the position signal Sp in the time from the pre-measurement contact to the measurement completion contact (contact required time Tc) is obtained, and the backlash is estimated from the change amount C.

  Further, when the torque command Ct is maximum (or minimum), that is, the peak A1 shown in FIG. 3A, or the amount of change per unit time of the torque command Ct is maximum (or minimum), that is, shown in FIG. When the peak B1 is reached, the contact detector 13 may be configured to detect a measurement completion contact. This eliminates the need to set a threshold when detecting a measurement completion contact.

  In the present embodiment, the torque command generator 11 generates a torque command Ct based on the drive command Cd and the position signal Sp. Thereby, when the change amount per unit time of the torque command Ct or the torque command Ct exceeds a preset threshold value in the direction corresponding to the reverse rotation drive, or when it becomes the maximum, the contact detector 13 The backlash can be estimated by detecting the measurement completion contact. As an example of a method for determining that the torque command Ct or the amount of change per unit time of the torque command Ct is the maximum, a method in which a maximum value is defined in advance, or a torque command Ct that is the largest in the reverse drive period TI or A method of maximizing the value of change per unit time of the torque command Ct can be mentioned.

  FIG. 4 is a diagram showing an example of a time-series waveform when the acceleration command value in the drive command Cd is constant. In the drawings (a) to (d), the horizontal axis represents time. On the vertical axis, (a) shows the acceleration command value by the drive command Cd, (b) shows the torque command Ct, (c) shows the position signal Sp, and (d) shows the contact signal Sc. Further, as shown in FIG. 4A, the drive command generator 10 gives a drive command Cd so that the acceleration of the motor 2 becomes constant during reverse rotation drive for a preset time Ta. As a result, as shown in FIG. 4B, when the motor 2 is driven in reverse rotation, the change in the torque command Ct is small except when the measurement completion contact is made, so that the peak A11 of the torque command Ct appears prominently. . In addition, when the drive command Cd that greatly changes the acceleration command value is used, the torque command Ct changes greatly even at a time other than the time when the measurement completion contact is made, and the torque command Ct peaks. The peak of the torque command Ct becomes noise and may be erroneously detected as a measurement completion contact. On the other hand, such a problem of noise can be solved by making the acceleration command value constant as in the present embodiment. Note that T1, T2, and T3 in FIG. 4D are a reverse drive period, a non-contact period, and a contact period, respectively, as in FIG. 3D.

  FIG. 5 is a diagram showing an example of a time-series waveform when the speed command value in the drive command Cd is constant. In the drawings (a) to (d), the horizontal axis represents time. On the vertical axis, (a) shows the speed command value in the drive command Cd, (b) shows the torque command Ct, (c) shows the position signal Sp, and (d) shows the contact signal Sc. Further, as shown in FIG. 5A, in the period Tb, the torque command Ct becomes a substantially constant value except for the time point when the measurement completion contact is made by the drive command Cd that makes the speed command value constant. Therefore, by using such a drive command Cd, as shown in FIG. 5B, when the drive-side gear 101a rotates by the amount corresponding to the backlash, the peak A12 of the torque command Ct appears more prominently. . The time change of the contact signal Sc at this time is ideally as shown in FIG. Note that T1, T2, and T3 in FIG. 5D are a reverse drive period, a non-contact period, and a contact period, respectively, as in FIG. 3D.

  In the prior art described in Patent Document 2, it is necessary to measure the mechanical contact between both gears 101a and 102a using the torque sensor of the drive shaft 101 and simultaneously measure the backlash using the position signal Sp. However, in the motor control device of the present embodiment, the torque command generator 11 generates the torque command Ct based on the drive command Cd and the position signal Sp, and the current controller 12 generates the motor 2 based on the torque command Ct. Is supplied with current Im, and the motor 2 is driven. Therefore, in the motor control apparatus of the present embodiment, the backlash can be measured as long as the position signal Sp is obtained as information obtained from the sensor. Thereby, it can connect to the apparatus of a wider structure.

Embodiment 2. FIG.
FIG. 6 is a block diagram for explaining a motor apparatus according to Embodiment 2 of the present invention. The present embodiment is different from the first embodiment in that the contact detector 13a detects the measurement completion contact using the position signal Sp instead of the torque command Ct.

  In the present embodiment, only components different from those in the first embodiment will be described, and the same or corresponding components in the figure are denoted by the same reference numerals, and description of those components will not be repeated.

  In the present embodiment, the contact detector 13 a detects the measurement completion contact inside the transmission mechanism 100 using the acceleration of the motor 2 obtained from the position signal Sp indicating the rotation state of the motor 2.

  In the present embodiment, the contact detector 13a derives the speed, acceleration, and jerk of the motor 2 by differentiating the position signal Sp once, twice, and three times with respect to time, respectively. Instead of differentiating the speed, acceleration, and jerk as described above, the difference in discrete time may be taken. Further, a high-pass filter may be applied to the position signal Sp before performing differentiation or difference in discrete time. Thereby, the fluctuation component of the position signal Sp can be made clearer.

  The contact detector 13a detects the measurement completion contact in the transmission mechanism 100 using the acceleration at the time of reverse rotation driving, and outputs the detection result as a contact signal Sc.

  FIG. 7 is a diagram illustrating an example of a time-series waveform at the time of reverse rotation driving of the motor control device according to the second embodiment. In the figure, regarding the vertical axis, (a) is the acceleration calculated from the position signal Sp, (b) is the jerk that is the amount of change of acceleration per unit time, (c) is the position signal Sp, and (d) is the contact. Signal Sc is shown.

  The contact detector 13a makes a measurement completion contact when the acceleration exceeds a preset threshold value (for example, a broken line a2 in FIG. 7A) in a direction for normal rotation driving (direction corresponding to normal rotation driving). Is detected. This is because the acceleration of the drive side gear 101a temporarily decreases (or increases) when both the gears 101a and 102a come into contact with each other. Moreover, the contact detector 13a may detect the measurement completion contact when the jerk exceeds the broken line b2 shown in FIG. As a method for determining the threshold value, for example, the threshold value may be dynamically set based on the torque command Ct. Note that the direction of forward rotation in acceleration and jerk (direction corresponding to forward rotation) is a positive direction in FIGS. 7A and 7B, for example.

  It should be noted that instead of setting the threshold value, the acceleration is maximum (or minimum), that is, peak A2 shown in FIG. 7A, or the jerk is maximum (or minimum), that is, peak B2 shown in FIG. 7B. In this case, the measurement completion contact may be detected. This eliminates the need to set a threshold value.

  In the present embodiment, when the contact detector 13a exceeds the acceleration calculated by the position signal Sp or the jerk calculated by the position signal Sp in a direction corresponding to the reverse rotation driving, or The backlash can be estimated by detecting that the measurement completion contact is detected when the maximum is reached. Therefore, the torque command generator 11 does not necessarily have to generate the torque command Ct based on the drive command Cd and the position signal Sp, and a configuration in which the torque command Ct is generated based only on the drive command Cd is also conceivable. As an example of a method for determining that the acceleration calculated by the position signal Sp or the jerk calculated by the position signal Sp is the maximum, a method in which these maximum values are defined in advance, or a reverse drive period TI A method of maximizing the value of the largest acceleration or jerk is mentioned.

  In the prior art described in Patent Document 2, it is necessary to measure the mechanical contact between both gears 101a and 102a using the torque sensor of the drive shaft 101 and simultaneously measure the backlash using the position signal Sp. However, in the present embodiment, the contact detector 13a detects the mechanical contact between the two gears 101a and 102a using the acceleration or jerk calculated using the position signal Sp. That is, the contact detector 13a detects a contact between the drive side gear 101a connected to the motor 2 and the load side gear 102a as a measurement completion contact using a signal calculated based on the position signal Sp, and detects the detection result. Output as a contact signal Sc. Further, the backlash estimator 14 estimates the backlash between the drive side gear 101a and the load side gear 102a based on the contact signal Sc and the position signal Sp. Therefore, in this embodiment, the backlash can be measured as long as the position signal Sp is obtained as information obtained from the sensor. Thereby, it can connect to the apparatus of a wider structure.

Embodiment 3 FIG.
FIG. 8 is a block diagram for explaining a motor apparatus according to Embodiment 3 of the present invention. The present embodiment is different from the first embodiment in that the contact detector 13b detects the measurement completion contact using the position signal Sp in addition to the torque command Ct.

  In the present embodiment, only components different from those in the first embodiment will be described, and the same or corresponding components in the figure are denoted by the same reference numerals, and description of those components will not be repeated.

The contact detector 13b first calculates an extraction disturbance De indicating the torque generated by the contact between the two gears 101a and 102a in the transmission mechanism 100. Next, the measurement completion contact is detected using the extraction disturbance De, and the detection result is output as the contact signal Sc. Note that the extraction disturbance De is calculated as in Expression (1).
De = Jm · Ac-Ct Formula (1)

  Here, the first term on the right side shows the torque for the inertia used to actually accelerate the motor 2. Jm and Ac represent the moment of inertia of the rotor of the motor 2 and the acceleration obtained by the position detector 3, respectively. The acceleration obtained by the position detector 3 is also called an acceleration signal. The second term on the right side is the torque command Ct generated by the torque command generator 11. As in equation (1), the torque of the transmission mechanism 100 calculated by taking the difference between the torque command Ct and the inertia torque, that is, the extracted disturbance De is used. Therefore, even when the acceleration command value in the drive command Cd changes and the torque command Ct fluctuates, a difference from the torque corresponding to the inertia due to the rotation of the motor 2 is taken to detect erroneous detection when detecting the measurement completion contact. The generation of causal peaks can be suppressed. Therefore, it is possible to accurately extract a change in torque due to a measurement completion contact inside the transmission mechanism 100.

  FIG. 9 is a diagram illustrating an example of a time-series waveform when the motor control device according to the third embodiment is driven in reverse rotation. In the figure, regarding the vertical axis, (a) shows the extracted disturbance De, (b) shows the amount of change per unit time of the extracted disturbance De, (c) shows the position signal Sp, and (d) shows the contact signal Sc. Show. When the position signal Sp changes by an angle corresponding to backlash, both the gears 101a and 102a come into contact with completion of measurement, and the extraction disturbance De increases rapidly. Thereby, the time differential value of the extraction disturbance De also increases rapidly.

  The contact detector 13b of the present embodiment is configured so that the extraction disturbance De exceeds the preset threshold indicated by the broken line a3 in FIG. 9A in the direction of normal rotation or the time differentiation of the extraction disturbance De. Assume that the measurement completion contact is detected when the value exceeds a preset threshold value indicated by a broken line b3 in FIG. Note that the forward driving direction (the direction corresponding to the forward driving) in the extraction disturbance De is a positive direction in FIGS. 9A and 9B, for example.

  When the extraction disturbance De is maximum (or minimum) like the peak A3 in FIG. 9A, or the time differential value of the extraction disturbance De is maximum (or minimum) as the peak B3 in FIG. 9B. ), The contact detector 13b may detect the measurement completion contact. This eliminates the need to set a threshold value.

  In the present embodiment, the contact detector 13b has a direction in which the extraction disturbance De calculated by the position signal Sp and the torque command Ct or the time differential value of the extraction disturbance De corresponds to the reverse drive with a preset threshold value. The backlash can be estimated by determining that the measurement completion contact is detected when the value exceeds or reaches the maximum. Therefore, the torque command generator 11 does not necessarily have to generate the torque command Ct based on the drive command Cd and the position signal Sp, and a configuration in which the torque command Ct is generated based only on the drive command Cd is also conceivable. As an example of a method for determining that the extraction disturbance De or the time differential value of the extraction disturbance De is the maximum, a method in which these maximum values are defined in advance, or the extraction disturbance De or extraction having the largest value in the reverse drive period TI A method of maximizing the time differential value of the disturbance De is mentioned.

  The contact detector 13b of the present embodiment detects a measurement completion contact based on the extracted disturbance De calculated by the torque command Ct and the position signal Sp. Therefore, even when using a motor device having a slow response speed to the torque command Ct, there is no delay in contact detection compared to using only the torque command Ct. Therefore, a decrease in backlash measurement accuracy can be suppressed.

  In the prior art described in Patent Document 2, it is necessary to measure the mechanical contact between both gears 101a and 102a using the torque sensor of the drive shaft 101 and simultaneously measure the backlash using the position signal Sp. However, in the present embodiment, the contact detector 13b calculates the extraction disturbance De based on the acceleration calculated using the position signal Sp and the torque command Ct, and the drive side gear 101a connected to the motor 2 and the load side A contact with the gear 102a is detected as a measurement completion contact, and the detection result is output as a contact signal Sc. Further, the backlash estimator 14 estimates the backlash between the drive side gear 101a and the load side gear 102a based on the contact signal Sc and the position signal Sp. Therefore, in this embodiment, the backlash can be measured as long as the position signal Sp is obtained as information obtained from the sensor.

  With the above-described configuration, in addition to the effects of the first embodiment, the motor control device of the present embodiment can accurately measure the backlash even if the motor control device has a slow response speed to the torque command Ct, and the drive command Cd Even when the command value by fluctuates greatly, it is possible to stably measure the backlash.

Embodiment 4 FIG.
FIG. 10 is a block diagram for explaining a motor apparatus according to Embodiment 4 of the present invention. The current detector 15 detects the current Im as a current signal Sim. The motor control apparatus according to the present embodiment is different from the first embodiment in that the motor control apparatus includes a contact detector 13c that detects a measurement completion contact using the current signal Sim instead of the position signal Sp.

  FIG. 11 is a diagram showing an example of a time-series waveform when the motor control device according to the fourth embodiment of the present invention is driven in reverse rotation. That is, the horizontal axis is time in (a) to (d) in the figure. On the vertical axis, (a) shows the current signal Sim, (b) shows the time differential value of the current signal Sim, (c) shows the position signal Sp, and (d) shows the contact signal Sc.

  In the present embodiment, only components different from those in the first embodiment will be described, and the same or corresponding components in the figure are denoted by the same reference numerals, and description of those components will not be repeated.

  The contact detector 13c of the present embodiment detects a measurement completion contact inside the transmission mechanism 100 from the current signal Sim. When the position signal Sp changes by an angle corresponding to backlash, both gears 101a and 102a come into contact with each other. This contact increases the moment of inertia that the motor 2 drives, so that the torque for driving the motor 2 becomes larger than in the non-contact state. Therefore, the current Im supplied to the motor 2 also increases abruptly. Here, the current value of the current signal Sim increases (or decreases), and the time differential value of the current signal Sim also increases (or decreases). For example, as shown in FIG. 11A, the current signal Sim also temporarily increases and a peak A4 appears. As shown in FIG. 11B, the time differential value indicating the change in the current signal Sim also temporarily increases (or decreases), and a peak B4 appears.

  As a method of detecting the measurement completion contact, as in the method described with reference to FIG. 3, when the current signal Sim exceeds the preset threshold value in the direction of reverse driving (direction corresponding to the reverse driving). Assume that a measurement completion contact is detected. In FIG. 11A, a broken line a4 is a preset threshold value. Instead of using the current signal Sim, a time differential value of the current signal Sim may be used. In this case, a broken line b4 in FIG. 11B is a preset threshold value. Note that the direction in which the current signal Sim and the time differential value of the current signal Sim are driven in the reverse direction (the direction corresponding to the reverse drive) is a negative direction in FIGS. 11A and 11B, for example.

  Instead of using a preset threshold value, when the current signal Sim is maximum (or minimum), that is, when the peak A4 shown in FIG. 11A is reached, or the time differential value of the current signal Sim is maximum (or minimum). That is, the measurement completion contact may be performed when the peak B4 shown in FIG. This eliminates the need to set a threshold value.

  In the present embodiment, the torque command generator 11 generates a torque command Ct based on the drive command Cd and the position signal Sp. Further, the current controller 12 supplies the current Im to the motor 2 based on the torque command Ct, and the current detector 15 detects the current signal Sim. As a result, when the current signal Sim or the amount of change per unit time of the current signal Sim exceeds a preset threshold value in the direction corresponding to the reverse rotation or becomes maximum, the contact detector 13c is The backlash can be estimated by detecting the measurement completion contact. As an example of a method for determining that the current signal Sim or the amount of change per unit time of the current signal Sim is maximum, a method in which these maximum values are defined in advance, or a current signal that is the largest in the reverse drive period TI A method of maximizing the time differential value of the amount of change per unit time of Sim or current signal Sim can be mentioned.

  In the prior art described in Patent Document 2, it is necessary to measure the mechanical contact between both gears 101a and 102a using the torque sensor of the drive shaft 101 and simultaneously measure the backlash using the position signal Sp. However, in the motor control device of the present embodiment, the torque command generator 11 generates the torque command Ct based on the drive command Cd and the position signal Sp, and the current controller 12 applies to the motor 2 based on the torque command Ct. The current Im is supplied and the motor 2 is driven. Further, the contact detector 13c detects the measurement completion contact using the current signal Sim. Therefore, in this embodiment, the backlash can be measured as long as the position signal Sp is obtained as information obtained from the sensor.

  With the above-described configuration, the motor control device of the present embodiment has the effects of the first embodiment.

Embodiment 5. FIG.
FIG. 12 is a block diagram illustrating a motor device according to Embodiment 5 of the present invention. The contact detector 13d according to the present embodiment is different from the fourth embodiment in that the measurement completion contact is detected using the position signal Sp in addition to the current signal Sim.

  In the present embodiment, only components different from those in the first embodiment will be described, and the same or corresponding components in the figure are denoted by the same reference numerals, and description of those components will not be repeated.

First, the contact detector 13d calculates an extraction disturbance De including disturbances such as mechanical contact generated inside the transmission mechanism 100. Next, the measurement completion contact is detected using the extraction disturbance De, and the detection result is output as the contact signal Sc. The extraction disturbance De is calculated as in equation (2).
De = Jm.Ac-Kt.Sim (2)

  However, in Equation (2), the first term on the right side is the torque for the inertia used to actually accelerate the motor 2 as in the first term on the right side of Equation (1). The second term on the right side of Equation (2) is the total torque generated in the motor 2 calculated from the current signal Sim. Here, Kt is a torque constant indicating the relationship between the current signal Sim corresponding to the current Im supplied to the motor 2 and the generated torque. The torque used to drive the transmission mechanism 100 can be derived by taking the difference between the total torque in the motor 2 and the torque for inertia as shown in Expression (2).

  The contact detector 13d detects the measurement completion contact using the torque derived from the current signal Sim instead of the torque command Ct. Therefore, the influence of the responsiveness of the torque command generator 11 and the current controller 12 can be reduced, and the disturbance due to the measurement completion contact inside the transmission mechanism 100 can be accurately calculated.

  As a method for detecting the measurement completion contact by the contact detector 13d, the measurement completion contact may be detected when the extraction disturbance De or the amount of change of the extraction disturbance De per unit time exceeds a threshold value. Alternatively, the measurement completion contact may be detected when the extraction disturbance De or the amount of change in the extraction disturbance De is maximum (or minimum). This eliminates the need to set a threshold value.

  In the present embodiment, the contact detector 13d has a direction in which the extraction disturbance De calculated by the position signal Sp and the current signal Sim or the time differential value of the extraction disturbance De corresponds to the reverse drive with a preset threshold value. The backlash can be estimated by determining that the measurement completion contact is detected when the value exceeds or reaches the maximum. Therefore, the torque command generator 11 does not necessarily have to generate the torque command Ct based on the drive command Cd and the position signal Sp, and a configuration in which the torque command Ct is generated based only on the drive command Cd is also conceivable. As an example of a method for determining that the extraction disturbance De or the time differential value of the extraction disturbance De is the maximum, a method in which these maximum values are defined in advance, or the extraction disturbance De or extraction that is the largest in the reverse drive period TI A method of maximizing the time differential value of the disturbance De is mentioned.

  The contact detector 13c of the fourth embodiment uses the current signal Sim for contact determination, and the response to the position signal Sp of the torque command generator 11 or the response to the torque command Ct of the current controller 12 is low. In some cases, there is a delay in contact detection, and the backlash measurement accuracy is lowered. Further, the contact detector 13a of the second embodiment uses the acceleration of the position signal Sp for contact determination, and when the acceleration command value of the drive command Cd is greatly changed, the contact may be erroneously detected. is there. In the present embodiment, since both the position signal Sp and the current signal Sim are used, it is possible to reduce contact detection delay or contact detection error.

  In the prior art described in Patent Document 2, it is necessary to measure the mechanical contact between both gears 101a and 102a using the torque sensor of the drive shaft 101 and simultaneously measure the backlash using the position signal Sp. However, in the present embodiment, the contact detector 13d calculates the extraction disturbance De based on the acceleration calculated using the position signal Sp and the current signal Sim, and the drive side gear 101a and the load side gear connected to the motor 2. The contact with 102a is detected as a measurement completion contact, and the detection result is output as a contact signal Sc. Further, the backlash estimator 14 estimates the backlash between the drive side gear 101a and the load side gear 102a based on the contact signal Sc and the position signal Sp. Therefore, in this embodiment, the backlash can be measured as long as the position signal Sp is obtained as information obtained from the sensor.

  With the above configuration, the motor control device of the present embodiment has a high accuracy because the contact detector 13d detects the measurement completion contact using both the position signal Sp and the current signal Sim in addition to the effects of the fourth embodiment. And backlash can be measured easily.

Embodiment 6 FIG.
FIG. 13 is a block diagram illustrating a motor device according to Embodiment 6 of the present invention. As shown in FIG. 13, the motor control apparatus of the present embodiment has a drive command generator 10a and a backlash estimator 14a instead of the drive command generator 10 and the backlash estimator 14 shown in FIG. Is different. The motor control device according to the present embodiment is configured such that backlash can be measured even when an external force Fd is applied to the load 4 and the load shaft 102 connected thereto.

  The drive command generator 10a generates a drive command Cd for performing a plurality of test drives described later. Although the details will be described later, the backlash estimator 14a estimates the backlash in consideration of the position of the load shaft 102 that changes according to the external force Fd.

  In the present embodiment, only components different from those in the first embodiment will be described, and the same or corresponding components in the figure are denoted by the same reference numerals, and description of those components will not be repeated.

  With the above configuration, in the present embodiment, even when the load shaft 102 is rotated by the external force Fd, the position of the load shaft 102 can be estimated and the backlash can be accurately measured by multiple forward and reverse rotations.

  FIG. 14 is a flowchart showing a backlash measurement procedure according to the sixth embodiment. The measurement procedure will be described along the flow shown in FIG. A symbol Si (i = 1, 2,...) In the flow diagram indicates each step.

  First, in step S1, the drive command generator 10a determines the direction of forward rotation and reverse rotation, the number of repetitions (number of times of test drive), acceleration, the amount of rotation of the drive shaft 101 during forward rotation and reverse rotation, and the like. Are obtained from a storage unit (not shown). In addition, you may acquire setting conditions via an external input terminal instead of acquiring from a memory | storage part.

  FIG. 15 is a diagram illustrating a direction in which the load shaft 102 of the transmission mechanism 100 of the motor control device according to the sixth embodiment of the present invention rotates in response to the external force Fd and a driving direction at the time of backlash measurement. In the drawing, the rotation direction of the load shaft 102 by the external force Fd is set in advance, the driving in the direction that prevents the rotation of the load shaft 102 is set as the forward rotation driving, and the driving in the reverse direction of the forward driving is the reverse driving. Is set.

  FIG. 16 is a diagram illustrating an example of a time-series waveform when the motor control device according to the sixth embodiment of the present invention generates a drive command Cd for performing test drive a plurality of times. In the figure, in each of (a), (b), and (c), the vertical axis indicates a position command value, a speed command value, and an acceleration command value. In (a) to (c), the drive command Cd is generated so that the test drive including the forward rotation drive and the reverse rotation drive is performed three times. In the following description, periods corresponding to three test drives are described as a test drive period Td1, a test drive period Td2, and a test drive period Td3, respectively. Further, the required contact times in the test drive periods Td1, Td2, and Td3 are Tc1, Tc2, and Tc3, respectively. The contact position displacements corresponding to the contact required times Tc1, Tc2, and Tc3 are Pc1, Pc2, and Pc3, respectively. In the test drive periods Td1 to Td3, drive commands Cd are generated so that parameters such as acceleration command values are different from each other. As shown in FIG. 16C, in each of the test drive periods Td1 to Td3, the double-dotted arrow and the double-dotted solid line indicate the forward drive period and the reverse drive period, respectively. As shown in FIG. 16C, the acceleration command value in the reverse drive period increases in the order of the test drive period Td1, the test drive period Td2, and the test drive period Td3. Moreover, the contact required time shown to Fig.16 (a) is shortened in order of Tc1, Tc2, and Tc3.

  Steps S2 and S3 will be described with reference to FIG. FIG. 17 is a diagram illustrating an internal structure of the transmission mechanism 100 of the motor device according to the sixth embodiment and a backlash measurement process.

  In step S2, the gears 101a and 102a come into contact with each other, that is, before measurement, inside the transmission mechanism 100 by the forward rotation of the motor 2.

  Next, in step S3, first, by reverse rotation driving of the motor 2, as shown by a solid line in FIG. 17B, the surface opposite to the tooth surface that was in contact with the gears 101a and 102a at the time of the pre-measurement contact. Contact. Here, the contact detector 13 detects a measurement completion contact and outputs a contact signal Sc. In the figure, the position of the load side gear 102a is influenced by the external force Fd, and is rotated from the position at the start of reverse rotation indicated by the dotted line in FIG. 17B to the position indicated by the solid line after the required contact time Tc.

  In step S4, the backlash estimator 14a compares the number of repetitions set in step S1 with the number of measurement completion contact detections, and determines whether or not the number of measurement completion contact detections has reached the number of repetitions. If the number of detections of the measurement completion contact is smaller than the number of repetitions (NO), steps S2 to S3 are repeated again in a test drive different from the previous time. On the other hand, if the number of detections of measurement completion contact is greater than or equal to the number of repetitions (YES), the process proceeds to step S5.

  In step S5, the load shaft position is estimated. In describing step S5, first, the load shaft position and the estimated load shaft position will be described.

  The load shaft position in the present embodiment will be described with reference to FIG. The load shaft position is based on the rotational position of the drive shaft 101 at the start of reverse rotation driving, and the rotational position of the load shaft 102 is converted into the rotational angle of the drive shaft 101 using the reduction ratio between the two gears 101a and 102a. It is a representation.

  For example, in FIG. 17A, the load axis position is an angle formed by a line segment Oa (solid line) and a line segment Ob (dotted line), and is a rotation angle corresponding to the backlash B. However, the line segment Oa (solid line) is the rotational position of the drive shaft 101 at the start of the reverse rotation drive. A line segment Ob (dotted line) is a load shaft position at the start of reverse rotation driving.

  In FIG. 17B, the load axis position is an angle formed by the line segment O-a (solid line) and the line segment O-b1 (solid line), and the line segment O-b ( It can be seen that the dotted line) moves to the line segment O-b1 (solid line), and the load shaft position increases as the load shaft 102 rotates. Since the line segment Oa (solid line) is the reference rotational position, it does not change from the start of reverse rotation driving. When both gears 101a and 102a are in contact as shown in FIG. 17B, the load shaft position corresponds to the contact position displacement Pc.

  Next, the estimated load shaft position will be described. FIG. 18 is a diagram for explaining the estimated load shaft position Ple (t) according to the sixth embodiment of the present invention. The estimated load axis position Ple (t) is an estimate of the load axis position at an arbitrary time t. However, the time t indicates the time from the reverse drive start time.

  In FIG. 18A, the vertical axis represents the load axis position, and the horizontal axis represents the time from the start of reverse rotation driving. FIG. 18B shows the amount of change in the position signal Sp on the drive shaft 101 from the start of reverse rotation driving. Moreover, the double-headed arrow in the figure indicates the size of the backlash B derived by the method described later. 18 (a) and 18 (b) plot the relationship between the contact position displacement Pc and the required contact time Tc when the number of repetitions is 3 in (Step S1). In the figure, each plot is a plot of the contact position displacement Pc and the required contact time Tc corresponding to the test drive periods Td1 to Td3 shown in FIG. 16, and is indicated as Pl1 to Pl3, respectively. For example, Pl1 is (Tc1, Pc1).

  Next, in step S5, the backlash estimator 14a uses the sets Pl11 to Pl3 of the contact position displacement Pc and the required contact time Tc corresponding to each of the test drive periods Td1 to Td3 to estimate the load axis position Ple (t ).

In the present embodiment, for simplicity of explanation, the external force Fd applied to the load shaft 102 has the same magnitude during the test drive periods Td1 to Td3, and the load shaft 102 driven with the external force Fd is in the test drive period Td1. It is assumed that they are driven at the same acceleration at Td3. The estimated load shaft position Ple (t) is approximated by an approximate function composed of a quadratic polynomial shown in Expression (3).
Ple (t) = Ka · t2 + Kb Formula (3)

  However, in Equation (3), Ka and Kb are coefficients relating to the acceleration of the load shaft 102 due to the external force Fd, and approximate coefficients representing the load shaft position at the start of the reverse rotation drive, that is, the backlash B shown in FIG. . Although details will be described later, the values of Ka and Kb are derived by using a plurality of data sets including the required contact time Tc and the contact position displacement Pc. The approximation function may be of any order and number of terms as long as it is suitable for approximating the position of the load shaft 102 that is moved by the external force Fd in addition to the expression (3). Instead of a polynomial, an approximate function using a logarithm, an exponent, a trigonometric function, or the like may be used.

  As a method for deriving the approximation coefficients Ka and Kb, for example, a least square method is used. In the least square method, the approximation coefficient is determined so that the sum of squares of the residuals between the set of the required contact time Tc and the contact position displacement Pc and the estimated load shaft position Ple (t) is minimized. Needless to say, a method other than the method of least squares may be used as a method for deriving the approximation coefficient. Needless to say, the magnitude of the external force Fd may be variable.

  To determine Ka and Kb, it is only necessary to obtain at least two sets of data sets for the required contact time Tc and the contact position displacement Pc. Therefore, when more than two sets of data sets are obtained, abnormal values may be removed. As a method for removing abnormal values, for example, when there is a data set whose standard residual with an approximate function is equal to or greater than a preset value, the data set is removed. Thereby, the dispersion | variation in a backlash measurement result can be suppressed. In the present embodiment, since the number of test drives is three, a maximum of one data set can be removed.

  In the above description, the drive command Cd is generated a plurality of times so that the acceleration at the time of reverse rotation (step S3) is different each time. However, by using the drive command Cd a plurality of times at the same acceleration, a plurality of drive commands Cd are used. A configuration in which an average value is calculated from the data set of the contact required time Tc and the contact position displacement Pc is also conceivable. In this case, the influence of the external force Fd changing with time can be averaged, and variations in the backlash measurement results can be suppressed. A configuration is also conceivable in which an abnormal value is removed from a data set of a plurality of required contact times Tc and a contact position displacement Pc by using a plurality of drive commands Cd at the same acceleration. As a configuration for removing the abnormal value, as in the case where the acceleration is different every time, for example, when there is a data set in which the standard residual with the approximate function is equal to or greater than a preset value, a configuration for removing the data set is included. Can be mentioned. In this case, the influence of the external force Fd changing instantaneously can be removed, and variations in the backlash measurement results can be suppressed.

  In the above description, the measurement completion contact is detected during reverse rotation driving (step S3), but the reverse rotation driving and the measurement completion contact detection are not necessarily performed simultaneously. First, the time-series waveform data obtained in steps S2 and S3 (eg, FIGS. 3A to 3D) are recorded in advance in a storage unit (not shown) for all test drives, and then stored in the storage unit. Detection of measurement completion contact in each test drive may be collectively performed by the contact detector 13 after step S4 using the recorded time-series waveform data.

  Finally, in step S6, the backlash estimator 14a estimates the backlash of the transmission mechanism 100 using the estimated load shaft position Ple (t). FIG. 18A shows an example of the estimated load shaft position Ple (t) estimated from the three sets of contact position displacement Pc and the required contact time Tc. When t = 0 is substituted into the estimated load shaft position Ple (t) shown in FIG. 18A, the backlash B can be calculated. In the present embodiment, | Kb |, which is the absolute value of Kb, corresponds to the estimated backlash B.

  In FIG. 18B, three dotted lines indicate the amount of change in the position signal Sp in each of the test drive periods Td1 to Td3. The round plot shown in FIG. 18B is the contact position displacement Pc, that is, the backlash B, which is the amount of change in the position signal Sp from the start of reverse rotation driving to the measurement completion contact when there is no external force Fd. When there is no external force Fd, the position of the load shaft 102 does not change. Thereby, in the test drive periods Td1 to Td3, even if the acceleration command value in the drive command Cd is changed, the required contact time Tc is changed, but the contact position displacement Pc is not changed. Therefore, the position corresponding to the backlash B indicated by the broken line in the figure is equal to the contact position displacement Pc. Therefore, it is plotted as a round shape shown in FIG.

  When the external force Fd is applied, if the required contact time Tc changes (extends) by changing (for example, decreasing) the acceleration of the driving gear 101a, the change (extension) of the required contact time Tc causes the load side gear 102a to change. The amount of rotation changes (increases). Therefore, the contact position displacement Pc changes (increases) by the amount of change (increase) in the rotation amount.

  For example, in the test drive period Td3, since the acceleration command value during reverse drive is the largest, the required contact time Tc3 is the shortest, and the load shaft 102 is rotated the least by the external force Fd. Thereby, the contact position displacement Pc becomes the smallest. The plot Pl3 is arranged on the left side and the upper side most in FIG. On the other hand, in the test drive period Td1, since the acceleration during the reverse drive is the smallest, the required contact time Tc1 is the longest, and the load shaft 102 rotates most by the external force Fd. Thereby, the contact position displacement Pc becomes the largest. In the drawing, the plot Pl1 is arranged on the rightmost side and the lower side.

  As described above, the backlash estimator 14a of the present embodiment derives the estimated load shaft position Ple (t) and estimates the backlash. Thereby, in addition to the effect of the first embodiment, the motor control device of the present embodiment can transmit the transmission mechanism 100 by the test drive including the forward rotation drive and the reverse rotation drive a plurality of times even in an environment where the external force Fd is applied to the load shaft 102. There is an effect that the backlash can be easily measured with high accuracy.

Embodiment 7 FIG.
FIG. 19 is a block diagram for explaining a motor device according to Embodiment 7 of the present invention. In the sixth embodiment, the direction of the external force Fd is set in advance. On the other hand, in this embodiment, it is assumed that the external force Fd works in an arbitrary direction.

  In the figure, the torque command Ct is used to determine the direction of the external force Fd applied to the load shaft 102, and a drive direction determiner 16 that newly outputs the drive direction Dd during forward rotation and reverse rotation is different. . Moreover, it is different in that it has a drive command generator 10b that generates a drive command Cd so that the acceleration is different for each reverse drive according to the drive direction Dd instead of the drive command generator 10a. In the present embodiment, only configurations different from those in Embodiment 6 will be described, and the same or corresponding configurations will be denoted by the same reference numerals, and description of those configurations will not be repeated.

  In the present embodiment, the direction of the external force Fd applied to the load shaft 102 is determined by the drive direction determiner 16 in step S1 of FIG. The drive command generator 10b performs control to stop the drive side gear 101a, and the drive direction determiner 16 determines the direction of the external force Fd using the torque command generated with both the gears 101a and 102a in contact with each other. Further, the driving direction Dd is determined.

  Specifically, the drive command Cd is generated by the drive command generator 10b so that the position signal Sp does not change, that is, the drive side gear 101a does not rotate. When the gears 101a and 102a are not in contact with each other, it is not necessary to apply torque to the driving gear 101a. Therefore, if the influence of friction applied to the driving shaft 101 is ignored, the torque command Ct is zero. After that, in a state where both the gears 101a and 102a are in contact with each other after a certain period of time, the load side gear 102a tries to rotate the drive side gear 101a by the external force Fd. However, since the drive-side gear 101a is controlled so as to be stationary, the drive-side gear 101a tries to rotate so as to cancel the force applied from the load-side gear 102a by the torque command Ct. Therefore, the direction of the external force Fd and the drive direction Dd of the forward rotation drive can be estimated using the rotation direction of the drive side gear 101a corresponding to the torque command Ct.

  For example, if both the gears 101a and 102a are in contact with each other and the torque command Ct generated in a stationary state is intended to rotate the driving gear 101a counterclockwise, the driving gear 101a is rotated clockwise. It can be determined that the external force Fd to be applied is working. Therefore, it can be seen that the rotation direction of the load side gear 102a, that is, the direction of the external force Fd is counterclockwise as shown in FIG. Furthermore, if the direction of the external force Fd is known, the drive direction Dd can also be determined.

  Instead of stopping the drive-side gear 101a, the drive-side gear 101a is reciprocated by reverse rotation drive and forward rotation drive, and the torque command Ct at the time of forward rotation drive and at the time of reverse rotation drive is compared, so that the drive direction Dd may be determined. The drive direction determiner 16 may determine the drive direction Dd from the current Im of the motor 2 instead of the torque command Ct.

  The motor control device of the present embodiment may be configured to include any one of the contact detectors 13a, 13b, 13c, and 13d instead of the contact detector 13, and in those cases as well, Backlash can be measured.

  With the above configuration, the motor control device of the present embodiment automatically determines the drive direction of the drive command Cd and reduces backlash even when the external force Fd is applied to the load shaft 102 in addition to the effects of the first embodiment. There is an effect that it can be measured.

Embodiment 8 FIG.
FIG. 20 is a block diagram for explaining a motor apparatus according to Embodiment 8 of the present invention. In the present embodiment, the contact detector 13e detects the measurement completion contact inside the transmission mechanism 100 within a range in which the position signal Sp indicating the rotation state of the motor 2 is determined by a preset minimum detection position and maximum detection position. This is different from the first embodiment.

  With the above configuration, in the present embodiment, stable contact can be detected even when there are many disturbances such as the influence of friction and deceleration, and the backlash can be measured with high accuracy.

  In the present embodiment, only components different from those in the first embodiment will be described, and the same or corresponding components in the figure are denoted by the same reference numerals, and description of those components will not be repeated.

  FIG. 21 is a diagram illustrating an example of a time-series waveform at the time of reverse rotation driving of the motor control device according to the eighth embodiment. In the first embodiment, the contact detector 13 determines contact during reverse rotation regardless of the position of the motor 2 indicated by the position signal Sp. However, the torque command Ct and the amount of change per unit time of the torque command Ct have a peak X13 shown in FIG. 21 (a) or a peak Y13 shown in FIG. You may have. Further, the amount of change per unit time of the torque command Ct may have a peak Z13 shown in FIG. 21B due to an undesired contact between the two gears 101a and 102a when the motor 2 decelerates. Therefore, in the first embodiment, the contact detector 13 may erroneously detect contact by the peak X13, the peak Y13, or the peak Z13, and the backlash estimation accuracy may deteriorate.

  The contact detector 13e of the present embodiment is configured so that the position of the motor 2 indicated by the position signal Sp exceeds the preset minimum detection position S13 in the reverse drive direction, and then sets the preset maximum detection position L13 in the reverse drive direction. Detect contact in the period until it is exceeded. That is, contact is detected in a period T13 shown in FIG. 21D, and a contact signal Sc indicating measurement completion contact is generated.

  As a method for detecting the measurement completion contact, as in the method described with reference to FIG. 3, the torque command Ct is driven in the direction in which the predetermined threshold value a1 indicated by the broken line is driven in the reverse direction (the direction corresponding to the reverse drive). Suppose that the measurement completion contact is detected when exceeding. Instead of using the torque command Ct, the time differential value of the torque command Ct may be used, and the threshold value of the broken line b1 may be used instead of using the threshold value a1.

  Instead of using a preset threshold value, the torque command Ct is maximum (or minimum), that is, the peak A13 shown in FIG. 21A, or the time differential value of the torque command Ct is maximum (or minimum). ) That is, the measurement completion contact may be performed when the peak B13 shown in FIG. This eliminates the need to set a threshold value.

  However, as described above, even when the threshold value is exceeded and when a peak is used, contact detection is not performed outside the period T13, and a signal indicating measurement completion contact is not generated.

  The minimum detection position is desirably set to a value sufficiently smaller than the assumed backlash, and can be determined from the influence of friction on the torque command Ct and the standard processing accuracy when the transmission mechanism 100 is manufactured. The maximum detection position is desirably set to a value sufficiently larger than the assumed backlash, and an appropriate value can be selected from the motor position at which deceleration is started, the number of gear teeth, the shape, and the like.

  Note that when the measurement completion contact is detected using the position signal Sp instead of the torque command Ct as in the contact detector 13a in the second embodiment, the torque command Ct and the torque command Ct are detected as in the contact detector 13b in the third embodiment. When the measurement completion contact is detected using the position signal Sp, when the measurement completion contact is detected using the current signal Sim as in the contact detector 13c of the fourth embodiment, and the contact detector of the fifth embodiment Similarly to the present embodiment, when the measurement completion contact is detected using the current signal Sim and the position signal Sp as in 13d, the range in which the contact detector of each embodiment is determined by the minimum detection position and the maximum detection position. Thus, it is possible to detect the measurement completion contact inside the transmission mechanism 100.

  Further, as in the sixth embodiment, the drive command generator 10a generates a drive command Cd for performing the test drive a plurality of times instead of the drive command generator 10, and the backlash estimator 14a is replaced with the backlash estimator 14. When the backlash is estimated, the measurement completion contact inside the transmission mechanism 100 can be detected within the range determined by the minimum detection position and the maximum detection position by the contact detector 13 as in the present embodiment. .

  As described above, the motor control device of the present embodiment can measure the backlash of the transmission mechanism 100 without erroneously detecting contact even when there are many disturbances such as friction and deceleration. As a result, the backlash can be measured with high accuracy using an apparatus having a wider configuration.

  1 motor controller, 2 motor, 3 position detector, 4 load, 10, 10a, 10b drive command generator, 11 torque command generator, 12 current controller, 13, 13a, 13b, 13c, 13d, 13e contact detection 14, 14a Backlash estimator, 15 Current detector, 16 Drive direction determiner, 100 Transmission mechanism, 101 Drive shaft, 101a Drive side transmission part (drive side gear), 102 Load shaft, 102a Load side transmission part (load) Side gear).

Claims (17)

A drive command generator for generating a drive command for driving the motor in the opposite direction to the one direction after driving the motor forward in one direction;
A torque command generator that generates a torque command for driving the motor based on the drive command and a position signal indicating an operation state of the motor;
Using the signal calculated based on the position signal, contact between the drive side transmission unit connected to the motor and the load side transmission unit connected to the load is detected as a measurement completion contact, and the detection result is used as a contact signal. A contact detector to output,
A motor control apparatus comprising: a backlash estimator that estimates a backlash between the drive side transmission unit and the load side transmission unit based on the contact signal and the position signal.   The contact detector, when the acceleration obtained from the position signal or a change amount per unit time of the acceleration exceeds a preset threshold in a direction corresponding to the positive drive, the measurement completion contact The motor control device according to claim 1, wherein the motor control device is detected.   The contact detector calculates an acceleration signal using the position signal, calculates an extraction disturbance based on the acceleration signal and the torque command, and detects the measurement completion contact using the extraction disturbance. The motor control device according to claim 1.   The contact detector calculates an acceleration signal using the position signal, calculates an extraction disturbance based on the acceleration signal and a current signal corresponding to a current supplied to the motor, and uses the extraction disturbance to perform the measurement. The motor control device according to claim 1, wherein completion contact is detected.   The motor control device according to claim 1, wherein the torque command generator generates the torque command based on the drive command and the position signal.   The contact detector detects the measurement completion contact when the torque command or a change amount per unit time of the torque command exceeds a preset threshold value in a direction corresponding to the reverse drive. The motor control device according to claim 5, wherein:   The contact detector, when the current signal corresponding to the current supplied to the motor or the amount of change per unit time of the current signal exceeds a preset threshold in the direction corresponding to the reverse drive The motor control device according to claim 5, wherein the measurement completion contact is detected. The motor control device according to claim 5, further comprising a drive direction determiner that determines a positive drive direction of the drive command based on the torque command. The motor control device according to claim 5, further comprising: a drive direction determiner that determines a positive drive direction of the drive command based on a current signal corresponding to a current supplied to the motor. The motor control device according to claim 1, wherein the drive command generator generates the drive command to perform the reverse drive beyond a predetermined maximum backlash allowable amount. The motor control device according to claim 1, wherein the drive command generator generates the drive command in which an acceleration or a speed of the motor at the time of reverse driving is constant for a preset time. The motor control device according to claim 1, wherein the contact detector detects the measurement completion contact within a range in which the position signal is determined by a preset minimum detection position and a maximum detection position. The backlash estimator estimates the backlash by calculating, as a contact position displacement, a change amount of the position signal of a required contact time, which is a time from the start of the reverse drive to the measurement completion contact. The motor control device according to claim 1.   The motor control device according to claim 13, wherein the drive command generator generates the drive command for causing the motor to perform a test drive including the forward drive and the reverse drive a plurality of times.   The motor control device according to claim 14, wherein the magnitudes of accelerations of the reverse drive are different from each other in the plurality of test drives.   The motor control apparatus according to claim 14, wherein the backlash estimator estimates the backlash using the required contact time and the contact position displacement corresponding to each of the plurality of test drives. A motor,
A position detector that outputs the operation state of the motor as a position signal;
A drive command generator that generates a drive command to reverse drive the motor in a direction opposite to the one direction after the motor is positively driven in one direction;
A torque command generator for generating a torque command for driving the motor based on the drive command and the position signal;
Using the signal calculated based on the position signal, contact between the drive side transmission unit connected to the motor and the load side transmission unit connected to the load is detected as a measurement completion contact, and the detection result is used as a contact signal. A contact detector to output,
A motor apparatus comprising: a backlash estimator that estimates a backlash between the drive-side transmission unit and the load-side transmission unit based on the contact signal and the position signal.

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