JP2014003836A - Motor controller and motor control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve response performance when resistance force in response to the velocity of an object to be moved is generated.SOLUTION: A motor controller comprises: a control unit for calculating a thrust command value from a command value externally inputted; a compensation coefficient calculation unit for calculating, when moving a movable element of a motor at certain acceleration velocity, a coefficient showing correlation between the moving velocity of the movable element and resistance force generated when moving an object on the basis of the moving velocity of the movable element and the thrust command value; a compensation value calculation unit for calculating a compensation value for the thrust command value on the basis of the moving velocity of the movable element and the coefficient; an operation unit for calculating a compensated thrust command value on the basis of the thrust command value and the compensation value; and a thrust control unit for driving the motor on the basis of the compensated thrust command value.

Description

  The present invention relates to a motor control device and a motor control method.

In order to move members and parts in OA (Office Automation) equipment, FA (Factory Automation) equipment, vehicles and the like, a configuration in which a guide device and a driving device (for example, a motor) are combined is often used. Yes. In such a configuration, it is necessary to control the drive device in accordance with the frictional force generated in the guide device or the like when moving a member or a component.
For example, Patent Document 1 describes that a motor is driven in accordance with sliding resistance generated when a roof glass provided in a vehicle is moved to open and close.

JP 2004-232280 A

  However, in the technique of Patent Document 1, since the control of suppressing the influence of sliding resistance is performed based on the position of the roof glass that is the object to be moved, the sliding is performed according to the speed of the object such as the roof glass. When resistance (resistance force) is generated, there is a problem that response performance in movement control is deteriorated.

  The present invention has been made to solve the above problems, and an object of the present invention is to improve the response performance when a resistance force corresponding to the speed of the object to be moved is generated, and to provide a motor control device and a motor control method. Is to provide.

  In order to solve the above problem, the present invention provides a motor control device that controls a motor that moves an object, a control unit that calculates a thrust command value from a command value input from the outside, and a movable unit of the motor. Based on the moving speed of the mover and the thrust command value when moving the child at a constant acceleration, the moving speed of the mover and the resistance force generated when moving the object A correction coefficient calculation unit that calculates a coefficient indicating a correlation with the above, a speed at which the mover moves, a correction value calculation unit that calculates a correction value for the thrust command value from the coefficient, the thrust command value, and the A motor control device comprising: an arithmetic unit that calculates a thrust command value corrected from a correction value; and a thrust control unit that drives the motor based on the corrected thrust command value.

  The present invention also relates to a motor control method performed by a motor control device that controls a motor that moves an object, a control step of calculating a thrust command value from a command value input from the outside, and a mover of the motor , When the movable element is moved at a constant acceleration, based on the moving speed of the movable element and the thrust command value, the moving speed of the movable element and the resistance force generated when moving the object A correction coefficient calculating step for calculating a coefficient indicating the correlation of the above, a speed at which the mover moves, a correction value calculating step for calculating a correction value for the thrust command value from the coefficient, the thrust command value and the correction A calculation step of calculating a thrust command value corrected from the value, and a thrust control step of driving the motor based on the corrected thrust command value. Which is another control method.

  According to the present invention, when the object is moved at a constant acceleration, the coefficient indicating the correlation of the counter force against the moving speed is calculated. Since the thrust command value is corrected based on the calculated coefficient and the moving speed of the object, the motor can be controlled while suppressing the influence of the resistance force generated according to the moving speed of the object. It is possible to improve the response performance when controlling.

It is a schematic diagram showing motor system 1 in this embodiment. It is a schematic block diagram which shows the structure of the motor control apparatus 10 in the embodiment. It is a figure which shows the outline | summary at the time of calculating the correction coefficient in this embodiment. It is a flowchart which shows an example of the motor control process which the motor control apparatus 10 of the embodiment performs.

  Hereinafter, a motor control device and a motor control method according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a case where the motor control device controls the linear motor will be described.

  FIG. 1 is a schematic view showing a motor system 1 in the present embodiment. The motor system 1 includes a motor control device 10 and a linear motor 20 as shown in FIG. The motor control device 10 controls to drive the linear motor 20 based on the position command value input from the host control device. The linear motor 20 includes a long stator 21, a mover 25 that moves on the stator 21, and a pair of guide devices 22 and 22 for assembling the stator 21 and the mover 25.

  The guide device 22 includes, for example, a track rail 23 and slide blocks 26 and 26 assembled via a ball. The track rail 23 of the guide device 22 is fixed to the base 54 of the stator 21, and the slide block 26 of the guide device 22 is fixed to the mover 25. Thereby, the mover 25 is freely guided along the track rail 23 on the stator 21.

  The stator 21 includes a plurality of driving magnets 24 arranged between the pair of track rails 23 and 23. The plurality of drive magnets 24 are arranged so that the N-pole and S-pole magnetic poles alternate in the direction in which the mover 25 moves. Further, the drive magnets 24 have the same length in the arranged direction, and a constant thrust can be obtained regardless of where the mover 25 is located on the stator 21. ing.

The mover 25 has three coils corresponding to the U phase, the V phase, and the W phase. Electric power is supplied from the motor control device 10 to the U-phase, V-phase, and W-phase coils via the power line 31. The mover 25 moves along the guide of the guide device 22 by the force generated by the interaction between the current flowing through each coil and the magnetic field generated by each drive magnet 24.
The movable element 25 is provided with a table 53 on which a conveyed product is placed and an encoder 27 that detects the distance that the movable element 25 has moved per unit time.

The encoder 27 is, for example, a measuring device that detects an optical or magnetic distance. The encoder 27 detects information recorded on a scale (not shown) provided in the stator 21 in advance, and the mover 25 moves. Detect the distance. The encoder 27 outputs distance information indicating the detected distance to the motor control device 10 via the transmission line 32.
The motor control device 10 controls the linear motor 20 based on the position command value and the distance information.

  FIG. 2 is a schematic block diagram showing the configuration of the motor control device 10 in the present embodiment. As shown in the figure, the motor control apparatus 10 includes a phase calculator 101, a speed calculator 102, a position calculator 103, a correction coefficient table 104, a correction value calculator 105, a position controller 106, a speed controller 107, and a correction. Value selector 108, switch 109, arithmetic unit 110, thrust controller 111, q-axis current controller 112, d-axis current controller 113, vector rotation / two-phase three-phase converter 114, power converter 115, current transformer 116, a vector rotation / three-phase / two-phase converter 117, and a correction coefficient calculator 118.

The phase calculator 101 calculates an electrical angle (phase) at the position of the mover 25 of the linear motor 20 based on the distance information input from the encoder 27 after the origin return process is performed. The phase calculator 101 outputs the calculated phase to the vector rotation / two-phase / three-phase converter 114 and the vector rotation / three-phase / two-phase converter 117. For example, the phase calculator 101 calculates the phase at the position of the mover 25 from the phase corresponding to the origin and the distance from the origin.
The speed calculator 102 calculates the speed (moving speed) at which the mover 25 moves based on the distance information input from the encoder 27. The speed calculator 102 outputs the calculated speed of the mover 25 to the correction value calculator 105 and the speed controller 107.

The position calculator 103 calculates the position of the mover 25 of the linear motor 20 based on the distance information input from the encoder 27 after the origin return process is performed. The position calculator 103 outputs the calculated position to the position controller 106.
In the origin return processing, for example, the mover 25 is moved to any one end on the stator 21 of the linear motor 20, and the end is set as the origin (distance = 0).

In the correction coefficient table 104, correction coefficients calculated by the correction coefficient calculator 118 are stored.
The correction value calculator 105 calculates a sliding resistance (resistance force) generated in the linear motor 20 using the correction coefficient stored in the correction coefficient table 104 and the speed calculated by the speed calculator 102. The correction value calculator 105 outputs the calculated sliding resistance to the switch 109 as a correction value in thrust control.

The position controller 106 moves the mover 25 to the position indicated by the position command value based on the deviation between the position command value input from the host controller and the position of the mover 25 calculated by the position calculator 103. The speed command value for making it calculate is calculated.
The speed controller 107 is a thrust command for moving the mover 25 at the speed indicated by the speed command value based on the deviation between the speed command value calculated by the position controller 106 and the speed calculated by the speed calculator 102. Calculate the value.
The position controller 106 and the speed controller 107 calculate the command value by, for example, PI control or PID control based on the input command value.

The correction value selector 108 determines whether the correction coefficient calculator 118 is calculating a correction coefficient. When the correction coefficient calculator 118 is calculating the correction coefficient, the correction value selector 108 selects not to correct the thrust command value using the correction value calculated by the correction value calculator 105, and switches 109. To control.
On the other hand, when the correction coefficient calculator 118 has not calculated the correction coefficient, the correction value selector 108 performs acceleration to increase the speed of the mover 25 from the speed command value calculated by the position controller 106. It is determined whether the vehicle is decelerating or reducing the speed. When acceleration for increasing the speed of the mover 25 is performed, the correction value selector 108 selects to perform correction by adding the correction value to the thrust command value, and controls the switch 109. When acceleration is performed to reduce the speed of the mover 25, the correction value selector 108 selects to perform correction by subtracting the correction value from the thrust command value, and controls the switch 109.

  The switch 109 determines whether or not to correct the thrust command value with the correction value calculated by the correction value calculator 105 according to the control of the correction value selector 108, and if so, sets the correction value for the thrust command value. Switch between adding and subtracting.

The arithmetic unit 110 corrects the thrust command value with the correction value in accordance with the switching of the switch 109, and outputs the corrected thrust command value to the thrust controller 111.
Based on the corrected thrust command value, the thrust controller 111 calculates a q-axis current command value for obtaining a thrust indicated by the thrust command value. At this time, the thrust controller 111 uses a thrust coefficient of the linear motor 20 to be controlled. Further, the thrust controller 111 outputs the calculated current command value to the q-axis current controller 112.

The q-axis current controller 112 determines the deviation based on the deviation between the q-axis current command value input from the thrust controller 111 and the q-axis current value input from the vector rotation / three-phase two-phase converter 117. The q-axis voltage command value is set to 0 (zero).
The d-axis current controller 113 sets the deviation to 0 (zero) based on the deviation between the input d-axis current command value and the d-axis current value input from the vector rotation / three-phase / two-phase converter 117. D-axis voltage command value is calculated.
The q-axis current controller 112 and the d-axis current controller 113 are, for example, command values by PI control or PID control based on an input command value, similarly to the position controller 106 and the speed controller 107. Is calculated. The d-axis current command value input to the d-axis current controller 113 is 0 (zero).

The vector rotation / two-phase / three-phase converter 114 includes a phase calculated by the phase calculator 101, a q-axis voltage command value calculated by the q-axis current controller 112, and a d-axis calculated by the d-axis current controller 113. The voltage command value is input. Based on the phase (electrical angle) of the linear motor 20, the vector rotation / two-phase / three-phase converter 114 determines voltages for the U phase, the V phase, and the W phase from the q-axis voltage command value and the d-axis voltage command value. Calculate the command value. The vector rotation / three-phase / two-phase converter 117 outputs the calculated voltage command value of each phase to the power converter 115.
The power converter 115 applies the voltage indicated by the voltage command value of each phase calculated by the vector rotation / two-phase three-phase converter 114 to the U-phase, V-phase, and W-phase coils of the linear motor 20. Specifically, the power converter 115 performs PWM control based on the voltage command value of each phase with respect to the external voltage supplied from the outside, converts the external voltage into a voltage indicated by the voltage command value, The voltage obtained by the conversion is applied to the linear motor 20.

The current transformer 116 measures the current value flowing through the U-phase and V-phase coils of the linear motor 20 and outputs the measurement result to the vector rotation / three-phase two-phase converter 117.
The vector rotation / three-phase / two-phase converter 117 includes a phase calculated by the phase calculator 101, a current value flowing through the U-phase and V-phase coils measured by the current transformer 116, and a U-phase and V-phase current. The value of the current flowing in the W-phase coil calculated from the value is input. The vector rotation / three-phase / two-phase converter 117 calculates a q-axis current value and a d-axis current value from the U-phase, V-phase, and W-phase current values based on the phase of the linear motor 20. The vector rotation / three-phase / two-phase converter 117 outputs the calculated q-axis current value to the q-axis current controller 112, and outputs the calculated d-axis current value to the d-axis current controller 113.

  The correction coefficient calculator 118 receives the moving speed calculated by the speed calculator 102 and the thrust command value calculated by the speed controller 107. The correction coefficient calculator 118 calculates a correction coefficient indicating a correlation with the sliding resistance that changes according to the moving speed from the moving speed and the thrust command value. The correction coefficient calculator 118 stores the calculated correction coefficient in the correction coefficient table 104.

Here, a correction coefficient calculation method by the correction coefficient calculator 118 will be described.
FIG. 3 is a diagram showing an outline when calculating the correction coefficient in the present embodiment. In the figure, the horizontal axis indicates time, and the vertical axis indicates the speed at which the mover 25 moves. In the drawing shows a control to stop by reducing the speed at a constant acceleration a movable member 25 which is stopped by increasing the speed at constant acceleration, at time t ₃ while changing the acceleration.

The correction coefficient calculator 118 calculates a correction coefficient based on combinations of speeds and thrust command values at different times during a period in which the mover 25 is moved at a constant acceleration. Here, when the thrust indicated by the thrust command value is f, the acceleration is a, the mass of the object to be moved including the mover 25 and the table 53 is m, and the sliding resistance that changes according to the speed is μ, The following equation (1) holds.
f = ma + μ (1)

Here, when the sliding resistances at time t ₁ and time t ₂ are μ ₁ and μ ₂ , the thrust command value f is expressed by the following equations (2) and (3).
f ₁ = ma + μ ₁ (2)
f ₂ = ma + μ ₂ (3)
The difference between the thrust force command value at time t ₁ and time t ₂ Metropolitan is expressed by the following equation (4).
f ₂ −f ₁ = μ ₂ −μ ₁ = μ _Δ (4)

The correction coefficient k can be calculated by dividing the thrust command value difference _μΔ by the speed difference at time t ₁ and time t ₂ .
k = _μΔ / (S ₂ −S ₁ ) (5)
By multiplying the correction coefficient k obtained by the equation (5) by the moving speed, it is possible to calculate the sliding resistance that changes according to the speed.

  When calculating the correction coefficient, the correction coefficient calculator 118 outputs a signal indicating that the correction coefficient is being calculated to the correction value selector 108. Further, the correction coefficient is calculated by the correction coefficient calculator 118 when performing origin return processing or at a predetermined timing.

FIG. 4 is a flowchart illustrating an example of a motor control process performed by the motor control device 10 of the present embodiment.
When motor control processing is started in the motor control device 10, a position command value is input to the position controller 106 (step S101), and the position controller 106 calculates a speed command value (step S102).
The speed controller 107 calculates a thrust command value from the speed command value (step S103), and the correction value calculator 105 calculates a correction value (sliding resistance) from the moving speed of the mover 25 and the correction coefficient (step S104). ).

The correction value selector 108 determines whether the speed of the mover 25 is increased (acceleration) or decreased (deceleration) from the change amount of the speed command value (step S105).
When accelerating (step S105: acceleration), in other words, when the sliding resistance hinders acceleration of the moving speed of the mover 25, the correction value selector 108 adds the correction value to the thrust command value. And the switch 109 is controlled to add the correction value. The calculator 110 adds the thrust command value and the correction value according to the switching of the switch 109, and outputs the addition result as a corrected thrust command value (step S106).
On the other hand, when the vehicle is decelerating (step S105: deceleration), in other words, when the sliding resistance is helping to reduce the moving speed of the mover 25, the correction value selector 108 subtracts the correction value from the thrust command value. The switch 109 is controlled so that the correction value is subtracted. The computing unit 110 subtracts the correction value from the thrust command value according to the switching of the switch 109, and outputs the subtraction result as a corrected thrust command value (step S107).

Each of the q-axis current controller 112 to the power converter 115 supplies power to the linear motor 20 based on the corrected thrust command value, drives the linear motor 20 (step S108), and the process proceeds to step S101. return.
Thereafter, in the motor control device 10, the processes from step S101 to step S108 are repeated.

As described above, in the motor control device 10 according to the present embodiment, the sliding resistance (when the correction value calculator 105 drives the linear motor 20 to move the conveyed object (object) placed on the table 53 ( Resistance force) is calculated, and the thrust command calculated by the speed controller 107 is corrected using the calculated sliding resistance as a correction value. Thereby, the influence of the sliding resistance produced when moving a target object can be suppressed, and the response performance in control of the linear motor 20 can be improved. In addition, since the sliding resistance is calculated based on the correction coefficient calculated by the correction coefficient calculator 118 and the speed at which the object is moved, the influence of the sliding resistance that changes according to the speed can be accurately suppressed. Can do.

  Further, in the motor control device 10, the correction value selector 108 determines whether the mover 25 is accelerated or decelerated, and when it is accelerated (when the absolute value of the speed is increased). Corrects the thrust command value so as to compensate for the thrust lost by the sliding resistance. On the other hand, when the vehicle is decelerating (the absolute value of the speed is close to 0), the thrust command value is corrected so as to reduce the force obtained by the sliding resistance. As a result, the speed can be quickly accelerated up to the speed indicated by the speed command value, the moving speed can be controlled without excessive deceleration, and the response performance can be improved.

  The correction coefficient calculator 118 in the above-described embodiment calculates a correction coefficient for each weight of the transported object placed on the table 53, and associates the calculated correction coefficient with the weight of the transported object in the correction coefficient table 104. You may make it memorize | store. In this case, weight information indicating the weight of the transported object placed on the table 53 is input to the motor control device 10, and the correction value calculator 105 corrects the resistance coefficient corresponding to the weight indicated by the weight information. A correction value is calculated using the read resistance coefficient read from the coefficient table 104. Thereby, even when sliding resistance changes with the weight of a conveyed product, control which suppressed the influence of sliding resistance can be performed and response performance can be improved.

  The correction coefficient calculator 118 calculates a resistance coefficient every time the linear motor 20 is controlled, and when the calculated correction coefficient is a value outside a predetermined appropriate range, or when the calculated correction coefficient and the previously calculated correction are calculated. When the absolute value of the difference from the coefficient is a value equal to or greater than a predetermined threshold, problems such as aged deterioration of the lubricant, a failure in the mechanism for moving the conveyed product such as the guide device 22 or the linear motor 20 occur. It may be determined that error information is output. Thereby, the user can grasp | ascertain the malfunction which arises in the motor system 1. FIG. As the output of error information, for example, a lamp or the like is turned on or an alarm sound is sounded.

  The correction coefficient calculator 118 also displays the guidance device 22 and the linear motor 20 when the absolute value of the difference between the calculated correction coefficient and the correction coefficient stored in the correction coefficient table 104 is a predetermined threshold value or more. For example, it may be determined that a defect has occurred in the error information and output error information.

  In the example illustrated in FIG. 3, the configuration in which the correction coefficient calculator 118 calculates the correction coefficient from the two movement speeds and the thrust command value corresponding to each movement speed has been described. However, a plurality of correction coefficients may be calculated from three or more moving speeds and a thrust command value corresponding to each moving speed. That is, the speed range for moving the mover 25 may be divided into a plurality of sections, and the correction coefficient may be calculated for each section. In this case, the correction coefficient calculator 118 stores the movement speed range and the correction coefficient in association with each other in the correction coefficient table 104, and the correction value calculator 105 performs correction using the correction coefficient corresponding to the movement speed of the mover 25. Calculate the value. Thereby, even when the relationship between the speed and the sliding resistance is not proportional, the influence of the sliding resistance can be suppressed.

  Moreover, although the structure which moves a conveyed product using the linear motor 20 was demonstrated in the motor system 1 in the above-mentioned embodiment, it is good also as a structure which moves a conveyed product using a rotary motor.

  The motor control apparatus 10 described above may have a computer system inside. In this case, the process of the motor control process described above is stored in a computer-readable recording medium in the form of a program, and the above process is performed by the computer reading and executing this program. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  The control unit described in the present invention corresponds to the speed controller 107 in the embodiment. The correction coefficient calculator described in the present invention corresponds to the correction coefficient calculator 118 in the embodiment. The correction value calculation unit described in the present invention corresponds to the correction value calculator 105 in the embodiment. The computing unit described in the present invention corresponds to the computing unit 110 in the embodiment. The thrust control unit described in the present invention corresponds to the thrust controller 111 in the embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Motor system, 10 ... Motor control apparatus, 20 ... Linear motor, 25 ... Movable element, 105 ... Correction value calculator, 107 ... Speed controller, 110 ... Calculator, 111 ... Thrust controller, 118 ... Correction coefficient calculation vessel

Claims (4)

A motor control device for controlling a motor for moving an object,
A control unit that calculates a thrust command value from a command value input from the outside;
When moving the mover of the motor at a constant acceleration, when moving the mover and the speed of the mover based on the moving speed of the mover and the thrust command value A correction coefficient calculation unit for calculating a coefficient indicating a correlation with the resistance force generated in
A correction value calculation unit that calculates a correction value for the thrust command value from the speed at which the mover moves and the coefficient;
A calculation unit for calculating a thrust command value corrected from the thrust command value and the correction value;
And a thrust control unit that drives the motor based on the corrected thrust command value. The motor control device according to claim 1,
The computing unit is
When accelerating the moving speed of the mover, the corrected thrust command value is calculated by adding the thrust command value and the correction value, and when the moving speed of the mover is decelerated. The motor control device, wherein the corrected thrust command value is calculated by subtracting the correction value from the thrust command value. The motor control device according to claim 1 or 2,
The correction coefficient calculation unit
An error information is output when it determines with the mechanism for moving the said motor or the said object having produced the malfunction based on the said coefficient. The motor control apparatus characterized by the above-mentioned. A motor control method performed by a motor control device that controls a motor that moves an object,
A control step for calculating a thrust command value from a command value input from the outside;
When moving the mover of the motor at a constant acceleration, when moving the mover and the speed of the mover based on the moving speed of the mover and the thrust command value A correction coefficient calculating step for calculating a coefficient indicating a correlation with the resistance force generated in
A correction value calculating step for calculating a correction value for the thrust command value from the moving speed of the mover and the coefficient;
A calculation step of calculating a thrust command value corrected from the thrust command value and the correction value;
And a thrust control step of driving the motor based on the corrected thrust command value.

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