JP2017123763A - Motor drive controller and machine tool including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor drive controller capable of stopping a motor quickly and reliably at a predetermined stop position with as few revolutions as possible, even from a state where the motor is rotating at a relatively low speed or the motor is stopping, and to provide a machine tool including the same.SOLUTION: A motor drive controller has a motor state calculation unit 33, a maximum deceleration possible speed calculation unit 34 for calculating the maximum deceleration possible speed, an inertia measurement minimum distance calculation unit 35 for calculating the inertia measurement minimum distance, and an acceleration deceleration control unit 41 executing a second mode for decelerating by speed control and position control, after accelerating with the maximum torque, when the initial speed of the motor is less that the maximum deceleration possible speed, and the differential value goes above the inertia measurement minimum distance, and executing a third mode for decelerating with a set acceleration, after accelerating with the set acceleration, when the initial speed is less that the maximum deceleration possible speed, and the differential value goes below the inertia measurement minimum distance.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor drive control device for controlling the drive of a motor used in a machine tool or the like, and a machine tool including the same.

  Conventionally, as a control mode for controlling a motor used in a machine tool or the like, it is used when a motor is rotated at a constant speed and when a rotating shaft is made to coincide with a predetermined stop position (angle). There is a position control. When the motor is positioned from the rotational state to a predetermined stop position (angle), a sequence is adopted in which the motor is decelerated with the maximum torque by speed control and then the control mode is switched to position control and stopped. This is because in speed control, the maximum torque can be generated and decelerated quickly, while the maximum torque causes vibrations, overshoots, measurement errors, etc., and accurate positioning is not possible.

  In the above sequence, as shown in FIG. 20, if the timing for switching to position control is too late, the time for deceleration with the maximum torque becomes long and the speed is too low, so the time required for positioning becomes long. On the other hand, if the timing for switching to the position control is too early, the time for deceleration with the maximum torque is shortened, and the amount of rotation is unnecessarily increased, so that the time required for deceleration is lengthened. Therefore, in order to optimize the positioning operation so that the total number of rotations of the motor is minimized, it is important to switch to position control at an optimal timing.

  However, in a motor such as a machine tool, the generated inertia (rotational moment of inertia) varies depending on the weight and shape of a workpiece (workpiece) gripped by a rotary shaft. Therefore, as shown in FIG. 21, when the inertia is small, the deceleration when decelerating with the maximum torque is large, and as shown in FIG. 22, when the inertia is large, the deceleration when decelerating with the maximum torque is large. The deceleration is small. Therefore, the optimum switching timing described above varies depending on the inertia, and also varies depending on the initial angle and positioning angle of the rotating shaft.

  In the second embodiment of Japanese Patent Application Laid-Open No. 2014-7790, the above-described switching timing is fixed at a base rotation speed inherent to the motor, and the base rotation speed is reduced to the base rotation speed and the base rotation speed. If it is lower, a motor drive control device has been proposed that decelerates to a stop position at a constant deceleration based on the minimum required deceleration distance (Patent Document 1).

JP 2014-7790 A

  However, in the invention described in Patent Document 1, since it is necessary to measure the position detection value and the maximum acceleration during high-speed rotation with the maximum torque, a measurement error is likely to occur, and it is difficult to take an overshoot countermeasure. There is. In addition, when it is not possible to stop at a predetermined stop position due to the overshoot or the like, as shown in FIG. 23, it is necessary to temporarily stop and then accelerate / decelerate again to make another rotation. There is also a problem that the time until stopping is unnecessarily prolonged.

  Therefore, the inventors of the present application can stop the motor at a predetermined stop position quickly and surely with as few revolutions as possible by optimizing the switching timing from speed control to position control in Japanese Patent Application No. 2015-136510. A new motor drive control technology is proposed. However, although this technology is suitable for positioning from a state where the motor is rotating at a high speed, positioning from a state where the motor is rotating at a relatively low speed or from a state where it is stopped is possible. There was room for improvement in positioning.

  The present invention has been made based on the background art as described above. Even when the motor is rotating at a relatively low speed or stopped, the rotation speed is as low as possible. It is an object of the present invention to provide a motor drive control device capable of quickly and reliably stopping a motor at a predetermined stop position and a machine tool including the motor drive control device.

  The motor drive control device according to the present invention enables a motor to be quickly and reliably placed at a predetermined stop position with as few revolutions as possible even when the motor is rotating at a relatively low speed or from a stopped state. In order to solve the problem of stopping, based on the position information of the motor detected by the position detection means, the current speed of the motor, the acceleration or deceleration of the motor, and the difference between the current position and the stop position A motor state calculation unit that calculates a value, a maximum decelerable speed calculation unit that calculates the maximum decelerable speed that is the minimum value of the speed at which the motor can be stably stopped even if the motor is decelerated and controlled with the maximum torque, and the inertia is minimum An inertia measurement minimum distance calculation unit for calculating an inertia measurement minimum distance, which is a minimum value of a movement distance necessary for measuring the inertia at the time, and the mode When the initial speed at the start of the drive control is less than the maximum decelerable speed and the difference value is equal to or greater than the minimum inertia measurement distance, the second mode is accelerated by maximum torque and then decelerated by speed control and position control. When the initial speed is less than the maximum decelerable speed and the difference value is smaller than the inertia measurement minimum distance, after accelerating at a set acceleration smaller than the maximum acceleration when accelerating with the maximum torque, And an acceleration / deceleration control unit that executes a third mode of decelerating at the set acceleration.

  Further, as one aspect of the present invention, in order to solve the problem of appropriately realizing the second mode, when the acceleration / deceleration control unit executes the second mode, a margin is set for the maximum deceleration of the motor. A position control deceleration calculating unit that calculates a position control deceleration by multiplying a ratio for use, the initial speed, the maximum acceleration, the position control deceleration, the difference value, and the margin setting The acceleration time at the maximum acceleration, the deceleration time at the maximum deceleration, and the position control time based on the ratio and the position control time set as the minimum value of the drive control time with the position control deceleration A first maximum speed calculation unit that calculates a speed at which the sum of the motor and the motor is controlled as a first maximum speed for switching the drive control from acceleration control to deceleration control, the maximum deceleration, and the first maximum speed, The above Based on the minute value, the margin setting ratio, and the position control time, the speed at which the sum of the moving distance at the maximum deceleration and the moving distance at the position control deceleration is minimized, A switching speed calculation unit that calculates a second control speed for switching the motor drive control from the speed control to the position control, and the acceleration / deceleration control unit is operable while the motor speed is smaller than the first maximum speed. The acceleration control is performed with the maximum torque, the deceleration control is performed with the maximum torque when the speed of the motor reaches the first maximum speed, and the deceleration for position control is performed after the motor speed becomes smaller than the second control speed. Deceleration control may be performed with.

  Furthermore, as one aspect of the present invention, in order to solve the problem of appropriately realizing the third mode, when the acceleration / deceleration control unit executes the third mode, the set acceleration and the difference value are And a second maximum speed calculation unit that calculates a second maximum speed for switching the drive control of the motor from acceleration control to deceleration control, wherein the acceleration / deceleration control unit is configured such that the motor speed is the second maximum speed. The acceleration may be controlled with the set acceleration as long as the speed is smaller, and when the speed of the motor reaches the second maximum speed, the acceleration may be controlled with the set acceleration.

Further, as one aspect of the present invention, in order to solve the problem of determining whether to control in the second mode or in the third mode, the inertia measurement minimum distance calculation unit calculates the following equation (2): The minimum inertia measurement distance may be calculated using
S _min = a _max (2T _i ² + XT ² −X ² T ² ) / 2 + ω ₀ T _i (2)
However, each symbol represents the following.
ω ₀ : Initial speed a _max : Maximum set acceleration X: Margin setting ratio T _i : Time required for measuring inertia T: Position control time

Furthermore, as one aspect of the present invention, in the second mode, in order to solve the problem of minimizing the sum of the acceleration time at the maximum acceleration, the deceleration time at the maximum deceleration, and the position control time, the first maximum The speed calculation unit may calculate the first maximum speed ω _max1 by the following formula (5) using the minimum value of the rotation speed n required until the motor satisfying the following formula (6) stops. .
ω _max1 = √ [{ω ₀ ² −a ₁ ² T ² X (1−X)} / 2 + a ₁ (L + 2πn)] (5)
n ≧ [[ω ₀ ² + a ₁ ² T ² X (1-X)] / 2a ₁ −L] / 2π Formula (6)
However, each symbol represents the following.
ω ₀ : Initial speed a ₁ : Maximum acceleration (maximum deceleration)
n: Number of rotations required until the motor stops L: Difference value between the current position and the stop position X: Margin setting ratio T: Position control time

  A machine tool according to the present invention includes the motor drive control device according to any one of the above-described aspects.

  According to the present invention, even when the motor is rotating or stopped at a relatively low speed, the motor can be quickly and reliably stopped at a predetermined stop position with as few revolutions as possible. it can.

1 is a block diagram illustrating an embodiment of a motor drive control device according to the present invention and a machine tool including the motor drive control device. FIG. It is a figure which shows the torque characteristic of a motor. It is a figure which shows operation | movement of the motor by the drive control of this embodiment. It is a figure which shows operation | movement of the motor by the drive control of this embodiment, and operation | movement when not setting position control time. In this embodiment, it is a figure explaining the calculation method of the maximum decelerable speed. In this embodiment, it is a figure explaining the inertia measurement minimum distance. In this embodiment, it is a figure explaining the calculation method of an inertia measurement minimum distance. It is a figure which shows the operation | movement of the motor by the drive control of this embodiment, and the operation | movement at the time of giving a margin to deceleration from a high-speed area | region. In this embodiment, it is a figure explaining the calculation method of 2nd control speed. In this embodiment, it is a figure which shows the adjustment method of the deceleration for position control. In this embodiment, it is a figure explaining the calculation method of 1st maximum speed. It is a flowchart which shows operation | movement of the motor drive control apparatus of this embodiment. In this embodiment, it is a graph which shows operation | movement of a 1st mode. In this embodiment, it is a flowchart which shows operation | movement of a 1st mode. In this embodiment, it is a graph which shows operation | movement of a 2nd mode. In this embodiment, it is a flowchart which shows operation | movement of a 2nd mode. In this embodiment, it is a graph which shows operation | movement of a 3rd mode. In this embodiment, it is a flowchart which shows the operation | movement of a 3rd mode. It is the figure which compared the operation | movement by the motor drive control apparatus which concerns on this invention, and the operation | movement of patent document 1. FIG. In motor drive control, it is a figure which shows the relationship between the switching timing from speed control to position control, and the time taken to stop. FIG. 6 is a diagram illustrating switching timing when the workpiece inertia is small in motor drive control. FIG. 5 is a diagram illustrating switching timing when the inertia of a workpiece is large in motor drive control. In the drive control of patent document 1, it is a figure which shows operation | movement when it cannot stop at a stop position.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of a motor drive control device according to the invention and a machine tool including the same will be described with reference to the drawings.

  As shown in FIG. 1, the motor drive control device 1 according to the present embodiment controls driving of a motor 11 a used in the machine tool 11 based on an instruction from the host controller 10 and positions the motor at a predetermined stop position. Is for. Hereinafter, each configuration will be described in detail.

  The host controller 10 instructs the motor drive control device 1 regarding the drive control of the motor 11a, and is configured by a programmable logic controller (PLC), a personal computer, or the like. The host controller 10 has, as setting conditions to be output to the motor drive control device 1, a stop position, a positioning condition, a stop determination speed, a first control speed, a margin setting ratio, a position control time, and a set maximum acceleration. The inertia measurement time and the set acceleration can be set.

  The stop position is a position (angle) at which the rotation axis of the motor 11a is desired to be stopped. The positioning condition is for setting an allowable error range with respect to the stop position. For example, the positioning condition is set to “within ± 1 degree with respect to the stop position”. The stop determination speed sets a speed for determining whether or not the positioning of the motor 11a is completed.

  The first control speed indicates the motor speed at the timing when the maximum deceleration that is the maximum value of the deceleration of the motor 11a is calculated. In general, as shown in FIG. 2, the torque characteristic of the motor 11a outputs a constant torque up to a base rotational speed (base rotational speed) inherent to the motor 11a, but is weaker above the base rotational speed. The output (= torque × rotational speed) is controlled to be constant by field control. For this reason, in this embodiment, as shown in FIG. 3, the deceleration (slope) immediately after the motor speed is reduced to the base rotation speed is considered as the maximum deceleration, and the first control speed is the control target. The base rotation speed of the motor 11a is set.

  The margin setting ratio is a parameter for calculating the position control deceleration, which is the deceleration at the time of position control, by multiplying the maximum deceleration of the motor 11a. In the present embodiment, as shown in FIG. 3, the margin setting ratio is set such that the position control deceleration below the second control speed, which will be described later, is made slower than the maximum deceleration to provide a margin, and the motor 11a is always For example, a value of about 90 to 95% is set.

  The position control time is a parameter that is set as the minimum value of time for drive control with the position control deceleration. As described above, in this embodiment, a margin is set for the deceleration for position control. However, if the drive control time is too short with the deceleration for position control, as shown in FIG. Measurement errors may not be completely absorbed. In this case, since it is necessary to make one more rotation after the motor 11a is stopped, the time until the motor 11a is stopped is unnecessarily prolonged. Therefore, in this embodiment, the margin is set so as to execute the position control at least for the position control time, and a value of, for example, about 10 to 100 msec is set.

  The set maximum acceleration indicates the acceleration when the motor 11a is accelerated with the maximum torque when the inertia (rotational inertia) applied to the rotating shaft is minimum. In this embodiment, the case where the inertia is minimum is, for example, a case where a work or the like is not attached to the rotating shaft. Alternatively, when the same workpiece is repeatedly mass-produced and processed, the inertia measured with the processed workpiece attached is minimized. In the present embodiment, the set maximum acceleration is set in advance according to the type of the motor 11 a used in the machine tool 11. Note that when the inertia applied to the rotating shaft is minimum, the deceleration when the motor 11a is decelerated with the maximum torque is also the same as the set maximum acceleration. Therefore, the maximum acceleration including the deceleration is referred to as the set maximum acceleration.

  The inertia measurement time indicates the time required to measure the inertia applied to the rotating shaft. Usually, several cycles of data are required to measure inertia. For this reason, the inertia measurement time is ensured according to the type of the motor 11a used in the machine tool 11 and the like.

  The set acceleration is an acceleration used in a third mode described later. In the present embodiment, as the set acceleration, a value separately set as another parameter is used, such as an acceleration at the time of manual operation. However, the set acceleration is not limited to the value, and may be set to a value smaller than the maximum acceleration when accelerating with the maximum torque.

  The machine tool 11 cuts, drills, grinds, grinds, rolls, and cuts workpieces such as metal, wood, stone, and resin, such as a lathe, drilling machine, boring machine, milling machine, gear cutting machine, and grinding machine. It is a machine for performing processing such as forging and bending. As shown in FIG. 1, the machine tool 11 includes a motor 11a that is drive-controlled based on a drive signal supplied from an acceleration / deceleration control unit 41 of the motor drive control device 1, and position information (rotational angle position) of the motor 11a. ), And position detection means 11b such as a rotary encoder. In the present embodiment, the spindle motor of the machine tool 11 is a control target, but it is also possible to control another motor 11a.

  The motor drive control device 1 is constituted by a computer such as a numerical control device for controlling the machine tool 11 and stores various data as shown in FIG. 1 while the arithmetic processing means 3 performs arithmetic processing. Storage means 2 that functions as a working area of the computer, and arithmetic processing means 3 that executes various arithmetic processes by executing the motor drive control program 1a installed in the storage means 2 and functions as each component described later. Have. Hereinafter, each constituent means will be described.

  The storage means 2 includes a hard disk, a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory, etc. As shown in FIG. 1, a program storage unit 21 and a setting condition storage unit 22 are provided. Have.

  The program storage unit 21 is installed with a motor drive control program 1a for controlling the motor drive control device 1 of the present embodiment. The arithmetic processing means 3 executes the motor drive control program 1a so that the motor drive control device 1 as a computer functions as each component described later. In this embodiment, the motor drive control program 1a has a speed control mode for controlling at a constant speed as a basic control mode of the motor 11a, and a position control for positioning the rotary shaft at a desired stop position. Mode.

Further, as will be described later, the motor drive control program 1a is selected as a characteristic control mode according to the present invention according to the initial speed at the start of drive control of the motor 11a and the difference value from the current position to the stop position. It has the following three modes.
First mode: a mode suitable when the initial speed is lower than the vicinity of the base rotational speed and is equal to or higher than the maximum decelerable speed described later. Second mode: the initial speed is less than the maximum decelerable speed and the difference value is described later. Mode suitable for the case where the inertia measurement distance is greater than or equal to the third mode: Mode suitable for the case where the initial speed is less than the maximum decelerable speed and the difference value is smaller than the minimum inertia measurement distance

  The usage form of the motor drive control program 1a is not limited to the above configuration. For example, the motor drive control program 1a may be stored in a computer-readable non-transitory recording medium such as a CD-ROM or a USB memory, and directly read from the recording medium and executed. Moreover, you may utilize by a cloud computing system, an ASP (Application Service Provider) system, etc. from an external server.

  The setting condition storage unit 22 stores various setting conditions output from the host controller 10. In this embodiment, as described above, the stop position, the positioning condition, the stop determination speed, the first control speed, the margin setting ratio, the position control time, the set maximum acceleration, the inertia measurement time, and the setting The acceleration is set in advance by the host controller 10, and these setting conditions are read and stored in the setting condition storage unit 22.

  Next, the arithmetic processing means 3 is constituted by a CPU (Central Processing Unit) or the like, and by executing the motor drive control program 1a installed in the storage means 2, as shown in FIG. Unit 31, position information acquisition unit 32, motor state calculation unit 33, maximum decelerable speed calculation unit 34, inertia measurement minimum distance calculation unit 35, position control deceleration calculation unit 36, switching speed calculation unit 37, a position control deceleration adjustment unit 38, a first maximum speed calculation unit 39, a second maximum speed calculation unit 40, an acceleration / deceleration control unit 41, and a positioning completion determination unit 42. Yes. Hereinafter, each component will be described in more detail.

  The setting condition acquisition unit 31 acquires various setting conditions necessary for positioning the motor 11a. In the present embodiment, the setting condition acquisition unit 31 is the stop position, positioning condition, stop determination speed, first control speed, margin setting ratio, position control time, set maximum acceleration, and inertia measurement time output from the host controller 10. Are acquired, and these setting conditions are stored in the setting condition storage unit 22.

  The position information acquisition unit 32 acquires position information (rotational angle position) of the motor 11a. In the present embodiment, the position information acquisition unit 32 acquires the position information of the motor 11 a detected by the position detection unit 11 b provided in the machine tool 11 and outputs the position information to the motor state calculation unit 33 as shown in FIG. It is supposed to be.

  The motor state calculation unit 33 calculates various values indicating the state of the motor 11a. In the present embodiment, the motor state calculation unit 33 acquires the position information of the motor 11a detected by the position detection unit 11b from the position information acquisition unit 32, and calculates the state of the motor 11a based on the position information.

  Specifically, the motor state calculation unit 33 calculates a value obtained by differentiating position information once as the current speed of the motor 11a, and calculates a value obtained by differentiating position information twice as the acceleration or deceleration of the motor 11a. Further, as described later, the motor state calculation unit 33 calculates the maximum deceleration based on the deceleration data for several cycles in the first mode, and calculates the maximum based on the acceleration data for several cycles in the second mode. The acceleration is calculated. Further, the motor state calculation unit 33 calculates a difference value between the current position specified by the position information and the stop position stored as the setting condition.

  The maximum decelerable speed calculation unit 34 calculates the maximum decelerable speed that is the minimum value of the speed at which the motor 11a can be stably stopped even if the motor 11a is decelerated and controlled with the maximum torque. In the present embodiment, in addition to positioning from a state where the motor 11a is stopped, positioning from a state where the motor 11a is rotating at a relatively low speed is assumed. For this reason, when the motor 11a is decelerated and controlled with the maximum torque, it immediately stops and the threshold value of the speed at which the motor 11a cannot be stably stopped is calculated as the maximum decelerable speed. Based on the maximum decelerable speed, it is determined whether the control is performed in the first mode, the second mode, or the third mode.

Specifically, when the motor 11a is decelerated with maximum torque and stopped stably, as shown in FIG. 5, after decelerating with the maximum torque during the inertia measurement time, during the position control time. Deceleration is performed at a deceleration for position control (margin setting ratio × set maximum acceleration). Therefore, the maximum decelerable speed calculating unit 34 calculates the maximum decelerating rate by the following equation (1) based on the set maximum acceleration, inertia measurement time, margin setting ratio, and position control time stored in the setting condition storage unit 22. The possible speed ω _d is calculated.
ω _d = a _max T _i + Xa _max T (1)
However, each symbol represents the following.
a _max : set maximum acceleration T _i : inertia measurement time X: margin setting ratio T: position control time

  The inertia measurement minimum distance calculation unit 35 calculates an inertia measurement minimum distance that is a minimum value of a moving distance necessary for measuring the inertia when the inertia applied to the rotation axis is minimum. In the present embodiment, as described above, positioning from a state where the motor 11a is rotating at a relatively low speed and positioning from a state where the motor 11a is stopped are assumed. However, when the current position is very close to the stop position, it is assumed that the vehicle cannot be stopped at the shortest distance from the moment when the inertia is calculated, but is accelerated once and makes another round.

  For this reason, when the inertia is the minimum, the distance that is minimum traveled by measuring the inertia, and the distance that cannot stop at the stop position when accelerating and decelerating with the maximum torque is calculated as the minimum inertia measurement distance. . When the inertia actually exists, as shown in FIG. 6, the minimum distance becomes smaller than the minimum inertia measurement distance. For this reason, if the distance from the current position to the stop position is smaller than the minimum inertia measurement distance, the inertia cannot be stopped at the maximum torque regardless of the value of the inertia. Whether to control in the second mode or in the third mode is determined based on the minimum inertia measurement distance.

Specifically, the inertia measurement minimum distance, as shown in FIG. 7, between the initial speed omega ₀ state of inertia measurement time T _i, the movement distance S ₁ when the acceleration at specified maximum acceleration a _max, later total from the first maximum speed omega _max1 and moving distance S ₂ when the deceleration to a second control speed omega _2, a moving distance S ₃ to a stop from the second control speed omega ₂ between the position control time T to It is.

Here, the calculation method of the inertia measurement minimum distance will be specifically described. As shown in FIG. 7, the moving distances S _{1 to} S ₃ are represented by the following equations, respectively.
^{_{S 1 = a max T i 2}} /2 + ω 0 T i
^{_{S 2 = a max t 2 2}} /2 + ω 2 T i
^{_{S 3 = Xa max T 2/}} 2
The time _{t 2} when the deceleration from omega _max1 to omega ₂ is expressed by the following equation.
t ₂ = (ω _max1 −ω ₂ ) / a _max = T _i −XT

Therefore, the inertia measurement minimum distance calculation unit 35 calculates the inertia measurement minimum distance S _min using the following equation (2).
S _min = S ₁ + S ₂ + S ₃ = a _max (2T _i ² + XT ² −X ² T ² ) / 2 + ω ₀ T _i (2)
However, each symbol represents the following.
ω ₀ : Initial speed a _max : Maximum set acceleration X: Margin setting ratio T _i : Time required for measuring inertia T: Position control time

  The position control deceleration calculation unit 36 calculates a position control deceleration that is a deceleration used during position control in the first mode or the second mode. In the present embodiment, the position control deceleration calculation unit 36 acquires the maximum acceleration or maximum deceleration of the motor 11 a calculated by the motor state calculation unit 33 and acquires the margin setting ratio from the setting condition storage unit 22. To do. The position control deceleration calculation unit 36 calculates the position control deceleration by multiplying the maximum acceleration or the maximum deceleration by the margin setting ratio.

  Specifically, in the first mode, the position control deceleration calculation unit 36 calculates the position control deceleration by multiplying the maximum deceleration by the margin setting ratio. On the other hand, in the second mode, the position control deceleration calculation unit 36 assumes that the maximum deceleration at the maximum torque and the maximum acceleration coincide with each other, and multiplies the maximum acceleration by the margin setting ratio. The control deceleration is calculated. If the torque values are the same, the maximum deceleration becomes larger than the maximum acceleration due to the influence of friction, and the above assumption can be made because it is easy to stop safely.

  The switching speed calculation unit 37 calculates a second control speed that defines the timing for switching the drive control of the motor 11a from the speed control to the position control in the first mode or the second mode. As shown in FIG. 8, if a margin is given to the deceleration from the high speed region, the time required to stop increases even with a slight margin, and waste occurs. Therefore, the switching speed calculation unit 37 specifies the switching timing that can surely stop at the stop position while securing the time for deceleration with the maximum torque as much as possible.

  Specifically, the switching speed calculation unit 37 calculates the maximum deceleration and the difference value calculated by the motor state calculation unit 33, the first control speed, the margin setting ratio, and the position stored in the setting condition storage unit 22. Based on the control time, the speed at which the sum of the moving distance at the maximum deceleration and the moving distance at the position control deceleration is minimized is calculated as the second control speed.

Here, the calculation method of the second control speed will be specifically described. As shown in FIG. 9, from the first control speed ω ₁ to the second control speed ω ₂ , the vehicle is decelerated over the time t ₁ with the maximum deceleration a ₁ and until it stops from the second control speed ω ₂ . When the vehicle is decelerated over time t ₂ with the position control deceleration a ₂ , the following equations (a) to (d) hold.
_{S 1 = (ω 1 + ω} 2) t 1/2: the moving distance ... formula at the time of deceleration in _{a 1 (a)
S 2 = ω 2 t 2/} 2: the moving distance ... formula at the time of deceleration in _{a 2} (b)
ω ₁ = a ₁ t ₁ + a ₂ t ₂ Formula (c)
ω ₂ = a ₂ t ₂ Formula (d)

Further, since the moving distance until stopping is expressed as L + 2πn using the difference value L between the current position and the stopping position and the rotation speed n of the motor 11a, the following formulas (a) to (d) Equation (e) holds.
_{S 1 + S 2 = ω 1} t 1/2 + ω 2 (t 1 + t 2) / 2 = L + 2πn ... formula (e)
Further, the following relational expressions (f) and (g) are established by using the margin setting ratio X and the margin parameters of the position control time T described above.
a ₂ = a ₁ X Formula (f)
t ₂ ≧ T Equation (g)

In the above, when t ₁ = (ω ₁ −ω ₂ ) / a ₁ and t ₂ = ω ₂ / a ₂ derived from the above formulas (c) and (d) are substituted into the above formula (e), The following formula (h) holds.
ω ₂ ² (1 / 2a ₂ −1 / 2a ₁ ) + ω ₁ ² / 2a ₁ = L + 2πn Formula (h)
Therefore, the following formula (3) is derived for the second control speed ω ₂ by the above formula (h) and the above formula (f).
ω ₂ = √ [{X / (1-X)} · {2a ₁ (L + 2πn) −ω ₁ ² }] Equation (3)

Here, in order for the route (root) in the above formula (3) to be a positive number, the following formula (i) needs to be satisfied.
n ≧ (ω ₁ ² / 2a ₁ −L) / 2π Formula (i)
On the other hand, from the above formulas (d), (f), and (g), the following formula (j) holds as a restriction on the margin.
ω ₂ ≧ a ₂ T = a ₁ XT Equation (j)
Therefore, the following equation (4) is derived for the rotational speed n required until the motor 11a stops by the above equation (i) and the above equation (j).
n ≧ [[ω ₁ ² + {(1−X) / X} (a ₁ XT) ² ] / 2a ₁ −L] / 2π Formula (4)

That is, the switching speed calculation unit 37 calculates the second control speed ω ₂ by the following equation (3) using the minimum value of the rotation speed n necessary until the motor 11a satisfying the following equation (4) stops. It is like that.
ω ₂ = √ [{X / (1-X)} · {2a ₁ (L + 2πn) −ω ₁ ² }] Equation (3)
n ≧ [[ω ₁ ² + {(1−X) / X} (a ₁ XT) ² ] / 2a ₁ −L] / 2π Formula (4)
However, each symbol represents the following.
ω ₁ : First control speed (base rotation speed)
ω ₂ : Second control speed (switching speed)
a ₁ : Maximum deceleration n: Number of rotations required until the motor stops L: Difference value between current position and stop position X: Margin setting ratio T: Position control time

  The position control deceleration adjusting unit 38 adjusts the position control deceleration so as to absorb the measurement error caused by the position detecting means 11b in the first mode or the second mode. In the present embodiment, the position control deceleration adjusting unit 38 controls the position based on the latest position information while the acceleration / deceleration control unit 41 performs the deceleration control of the motor 11a at a speed smaller than the second control speed. Adjust the deceleration.

Specifically, as shown in FIG. 10, when the motor 11a is decelerated and controlled at a speed ω ₃ smaller than the second control speed, the remaining moving distance S ₃ to the stop position is multiplied by time t ₃ . When the vehicle decelerates, the following equation (k) holds as in the above equation (b).
_{S 3 = ω 3 t 3/} 2 ... formula (k)
Further, when the vehicle is decelerating at the position control deceleration a ₂ at that time, the following equation (1) is established for the velocity ω ₃ , as in the equation (d).
ω ₃ = a ₂ t ₃ Formula (l)
Therefore, the following formula (m) is derived from the above formulas (k) and (l).
S ₃ = ω ₃ ² / 2a ₂ Formula (m)

As described above, the position control deceleration adjustment unit 38 calculates the remaining movement distance S ₃ and the speed ω ₃ calculated by the motor state calculation unit 33 based on the latest position information while performing the position control. It is acquired and constantly monitored whether or not the above formula (m) is established. When the above formula (m) is not satisfied (when S ₃ ≠ ω ₃ ² / 2a ₂ ), it means that the position control deceleration a ₂ cannot be stopped at the stop position. It determines that require adjustment of the position control deceleration, and calculates the position control deceleration a ₃ after adjustment by the above formula the following equation obtained by modifying (m) (n).
a ₃ = ω ₃ ² / 2S ₃ Formula (n)
Then, the position control deceleration adjusting unit 38 is adapted to indicate the position control deceleration a ₃ after the adjustment to the deceleration control unit 41.

When adjusting the above-described deceleration for position control, if the post-adjustment position control deceleration a ₃ becomes larger than the maximum deceleration a ₁ due to the occurrence of a large disturbance or the like, an overshoot occurs. There is a risk that the desired control may become impossible, for example. Therefore, in the above case (a ₃ > a ₁ ), the position control deceleration adjusting unit 38 may appropriately reduce the margin setting ratio X and reset it. For example, when the margin setting ratio X is set to 95%, the above case is avoided by setting it to 90%. However, even when resetting as described above, overshoot and many rotations that occur before the resetting are unavoidable. Therefore, for mass production, etc., test processing is performed in advance with a predetermined margin setting ratio X, and if it is not successful, the margin setting ratio X on the safer side is set to minimize the influence of disturbance, etc. It is preferable to limit to the limit.

  The first maximum speed calculation unit 39 calculates a first maximum speed for switching the drive control of the motor 11a from the acceleration control to the deceleration control in the second mode. In the present embodiment, the first maximum speed calculation unit 39 is for setting the initial speed (current speed), the maximum acceleration and the difference value calculated by the motor state calculation unit 33, and the margin setting stored in the setting condition storage unit 22. Based on the ratio and the position control time, and the position control deceleration calculated by the position control deceleration calculating unit 36, the sum of the acceleration time at the maximum acceleration, the deceleration time at the maximum deceleration, and the position control time. The speed at which the value is minimum is calculated as the first maximum speed.

Here, the calculation method of the first maximum speed will be specifically described. As shown in FIG. 11, from the current speed ω ₀ to the first maximum speed ω _max1 , acceleration is performed with the maximum acceleration a ₁ over time t ₁ , and from the first maximum speed ω _max1 to the second control speed ω _2. The vehicle is decelerated over the time t ₂ at the maximum deceleration a ₁ and decelerated over the position control time T at the position control deceleration a ₂ (= Xa ₁ ) until the second control speed ω ₂ is stopped. In this case, the movement distances S _{1 to} S ₃ in each control section are represented by the following equations, respectively.
S ₁ = (ω _max1 + ω ₀ ) t _1/2 Formula (A)
S ₂ = (ω _max1 + ω ₂ ) t _1/2 Formula (B)
S ₃ = ω ₂ T / 2 Formula (C)
Further, time t ₁ when accelerating from ω ₀ to ω _max1 and time t ₂ when decelerating from ω _max1 to ω ₁ are expressed by the following equations, respectively.
t ₁ = (ω _max1 −ω ₀ ) / a ₁ Formula (D)
t ₂ = (ω _max1 −ω ₂ ) / a ₁ Formula (E)

Further, since the moving distance until stopping is expressed as L + 2πn using the difference value L between the current position and the stopping position and the rotation speed n of the motor 11a, the following formulas (A) to (C) are used. Formula (F) is established.
_{S 1 + S 2 + S 3} = (ω max1 + ω 0) t 1/2 + (ω max1 + ω 2) t 1/2 + ω 2 T / 2 = L + 2πn ... formula (F)
Further, the following relational expression (G) is established by using the margin setting ratio X and the margin parameter of the position control time T described above.
ω ₂ = a ₂ T = a ₁ XT Formula (G)

In the above, when the above formulas (D) and (E) are substituted into the above formula (F), the following formula (H) is established.
2ω _max1 ² −ω ₀ ² −ω ₂ ² + a ₁ Tω ₂ = 2a ₁ (L + 2πn) Equation (H)
Summarizing this for ω _max1 , since ω _max1 > 0, the following equation holds.
ω _max1 = √ [{ω ₀ ² + ω ₂ ² −a ₁ Tω ₂ )} / 2 + a ₁ (L + 2πn)] Formula (I)
Therefore, the following formula (5) is derived for the first maximum speed ω _max1 by the above formula (I) and the above formula (G).
ω _max1 = √ [{ω ₀ ² −a ₁ ² T ² X (1−X)} / 2 + a ₁ (L + 2πn)] (5)

Here, in order for the route in the above formula (5) to be a positive number, the rotation speed n required until the motor 11a stops needs to satisfy the following formula (6). .
n ≧ [[ω ₀ ² + a ₁ ² T ² X (1-X)] / 2a ₁ −L] / 2π Formula (6)

That is, the first maximum speed calculation unit 39 satisfies the following formula (6) and uses the minimum value of the rotation speed n required until the motor 11a stops, and the first maximum speed ω _max1 by the following formula (5). Is calculated.
ω _max1 = √ [{ω ₀ ² −a ₁ ² T ² X (1−X)} / 2 + a ₁ (L + 2πn)] (5)
n ≧ [[ω ₀ ² + a ₁ ² T ² X (1-X)] / 2a ₁ −L] / 2π Formula (6)
However, each symbol represents the following.
ω ₀ : Initial speed a ₁ : Maximum acceleration (maximum deceleration)
n: Number of rotations required until the motor stops L: Difference value between the current position and the stop position X: Margin setting ratio T: Position control time

  The second maximum speed calculation unit 40 calculates a second maximum speed for switching the motor drive control from the acceleration control to the deceleration control in the third mode. In the present embodiment, the second maximum speed calculation unit 40 accelerates motor drive control based on the set acceleration stored in the setting condition storage unit 22 and the difference value calculated by the motor state calculation unit 33. A second maximum speed for switching from control to deceleration control is calculated.

Specifically, assuming that the difference value L is within one rotation, the second maximum speed calculation unit 40 determines the time t until the second maximum speed is reached (the time until the stop position is reached). Half) and the set acceleration a _set , the following equation is established.
L = a _set t ² Formula (7)
In the third mode, assuming that the graph indicating the relationship between speed and time is an isosceles triangle, the second maximum speed ω _max2 is represented by a _set t. Therefore, the second maximum speed calculation unit 40 calculates the second maximum speed ω _max2 by the following formula (8).
ω _max2 = a _set × √ (L / a _set ) = √ (a _set L) (8)
However, each symbol represents the following.
a _set : set acceleration L: difference value between current position and stop position

  The acceleration / deceleration control unit 41 outputs a drive signal to the motor 11a to execute acceleration control and deceleration control. In the present embodiment, the acceleration / deceleration control unit 41 constantly monitors the current speed of the motor 11 a calculated by the motor state calculation unit 33. Based on the initial speed at the start of drive control of the motor 11a and the difference value from the current position to the stop position, one of the above-described first mode, second mode, and third mode is selected. It is supposed to be executed unilaterally.

  Specifically, in the first mode, the acceleration / deceleration control unit 41 performs deceleration control with the maximum torque if the motor speed is equal to or higher than the second control speed, and after the motor speed becomes smaller than the second control speed. Performs deceleration control with deceleration for position control. In the second mode, the acceleration / deceleration control unit 41 performs acceleration control with the maximum torque while the motor speed is lower than the first maximum speed, and performs deceleration control with the maximum torque when the motor speed reaches the first maximum speed. Then, after the motor speed becomes lower than the second control speed, the deceleration control is performed by the position control deceleration. Further, in the third mode, the acceleration / deceleration control unit 41 performs acceleration control at the set acceleration while the motor speed is smaller than the second maximum speed, and performs deceleration control at the set acceleration when the motor speed reaches the second maximum speed. To do.

Further, in the present embodiment, acceleration and deceleration control section 41, when the position control for deceleration by the position control deceleration adjusting unit 38 is adjusted, the deceleration controlled by the position control deceleration a ₃ after the adjustment (Position control) is executed.

  The positioning completion determination unit 42 determines whether or not the positioning of the motor 11a has been completed. In the present embodiment, the positioning completion determination unit 42 refers to the stop position, the positioning condition, and the stop determination speed stored in the setting condition storage unit 22 and acquires the position information (current position) acquired by the position information acquisition unit 32. Is within an allowable error range with respect to the stop position, and it is determined whether the current speed calculated by the motor state calculation unit 33 is equal to or less than the stop determination speed. The positioning completion determination unit 42 determines that the positioning is completed only when the current position is within an allowable error range with respect to the stop position and the current speed is equal to or less than the stop determination speed. .

  Next, the operation of the motor drive control device 1 of the present embodiment will be described with reference to the flowchart of FIG. In the present embodiment, positioning from a state where the motor 11a rotates at a relatively low speed or positioning from a stopped state is assumed. For this reason, when positioning from a state of rotating at a higher speed than the base rotational speed, the maximum torque is applied as long as the speed of the motor 11a is higher than the second control speed according to the drive control according to Japanese Patent Application No. 2015-136510. After the deceleration control (speed control) is performed and the speed of the motor 11a becomes smaller than the second control speed, the deceleration control (position control) is performed with the deceleration for position control.

  When the motor drive control device 1 according to the present embodiment controls the motor 11a of the machine tool 11 and performs positioning at a predetermined stop position, first, the setting condition acquisition unit 31 first outputs the stop position and positioning output from the host controller 10. A setting condition consisting of a condition, a stop determination speed, a first control speed, a margin setting ratio, a position control time, a set maximum acceleration, an inertia measurement time, and a set acceleration is acquired and stored in the setting condition storage unit 22 (step S1). . Thereby, the motor drive control device 1 shifts to the positioning sequence.

  Next, when the position information acquisition unit 32 acquires the position information detected by the position detection unit 11b (step S2), the motor state calculation unit 33 uses the current speed, acceleration, or acceleration of the motor 11a based on the position information. The deceleration and the difference value between the current position and the stop position are calculated (step S3). Thereby, the current state information of the motor 11a is grasped. In the subsequent processing steps, the processing corresponding to the position information acquisition step (step S2) by the position information acquisition unit 32 and the state information calculation step (step S3) by the motor state calculation unit 33 is summarized in one step. Shall be explained.

  Subsequently, the maximum decelerable speed calculating unit 34 calculates the maximum decelerable speed based on the set maximum acceleration, the inertia measurement time, the margin setting ratio, and the position control time (step S4). As a result, the minimum value of the speed at which the motor 11a can be stably stopped even when the motor 11a is decelerated with the maximum torque is obtained as the maximum decelerable speed. For this reason, if the current speed is equal to or greater than the maximum decelerable speed (step S5: NO), control is performed in the first mode (step S7).

  On the other hand, if the current speed is less than the maximum decelerable speed (step S5: YES), the inertia measurement minimum distance calculation unit 35 calculates the inertia measurement minimum distance in order to control in the second mode or the third mode (step S5). S6). As a result, when the inertia applied to the rotating shaft is the minimum, the minimum value of the movement distance necessary for measuring the inertia is obtained as the minimum inertia measurement distance. Therefore, if the difference value is equal to or greater than the minimum inertia measurement distance (step S8: YES), control is performed in the second mode (step S9). If the difference value is smaller than the minimum inertia measurement distance (step S8: NO), Control is performed in the third mode (step S10). Hereinafter, each of the first mode, the second mode, and the third mode will be described.

[1] Regarding the first mode When the first mode is executed, the initial speed of the motor 11a is present in the low speed range from the vicinity of the base rotational speed as shown in FIG. For this reason, as shown in FIG. 14, the acceleration / deceleration control unit 41 first starts the deceleration control of the motor 11a with the maximum torque (step S11). At this time, since the initial speed of the motor 11a is equal to or higher than the maximum decelerable speed, it is ensured that the motor 11a can be stably stopped without being immediately stopped even if the deceleration control is performed with the maximum torque.

  While decelerating at the maximum torque, the position information acquisition unit 32 acquires the position information, and the motor state calculation unit 33 calculates various state information (step S12) and repeats until the maximum deceleration is calculated (step S13). . As a result, the maximum deceleration in consideration of the influence of the inertia actually generated on the rotating shaft of the motor 11a is calculated. Further, as will be described later, since the maximum deceleration is calculated during the deceleration with the maximum torque, the optimum deceleration can always be performed for each of the workpieces having different inertias.

  When the maximum deceleration is calculated (step S13: YES), the position control deceleration calculation unit 36 calculates the position control deceleration by multiplying the maximum deceleration by the margin setting ratio (step S14). . Thereby, by setting an appropriate margin setting ratio, a deceleration for position control is calculated so that the motor 11a can always stop stably.

  Subsequently, the switching speed calculation unit 37 determines the movement distance and the position control decrease at the maximum deceleration based on the maximum deceleration, the first control speed, the margin setting ratio, the position control time, and the difference value. The speed that minimizes the sum of the moving distances at the speed is calculated as the second control speed (step S15). As a result, the optimum timing for switching the drive control of the motor 11a from the speed control to the position control is specified so that the motor 11a can be stopped at the stop position with the smallest number of rotations.

  In the present embodiment, the calculation of the second control speed uses two margin parameters, the margin setting ratio and the position control time. For this reason, even if there is a measurement error or disturbance due to the position detection means 11b, it can be stably controlled, and it is necessary to rotate it one turn without being positioned at the stop position, or to reversely rotate without preventing overshoot. There is no. In addition, the setting values of the margin parameters do not need to be changed depending on the work, and are intuitive and easy to set and adjust.

  Subsequently, while the vehicle is decelerated with the maximum torque, the position information acquisition unit 32 acquires position information, and the motor state calculation unit 33 calculates various state information (step S16), and the current speed of the motor 11a is the first speed. The process is repeated until it becomes slower than the two control speeds (step S17). As long as the speed of the motor 11a is equal to or higher than the second control speed (step S17: NO), deceleration control (speed control) is performed with the maximum torque. For this reason, the deceleration time at the maximum torque is ensured as much as possible, and the vehicle is quickly decelerated before switching to position control, so the time until the positioning is completed is shortened.

  On the other hand, when the speed of the motor 11a becomes smaller than the second control speed (step S17: YES), the position control deceleration adjusting unit 38 determines whether or not the position control deceleration needs to be adjusted (step S18). ). If adjustment is necessary (step S18: YES), the position control deceleration adjustment unit 38 calculates and adjusts a new position control deceleration (step S19).

  As a result, even if a position control deceleration that cannot be stopped at the stop position due to a measurement error of the position detection means 11b is set, a margin is secured by the position control time. Position control is performed during the position control time. Therefore, based on the latest position information, the position control deceleration is adjusted as appropriate so that the vehicle can be reliably stopped at the stop position.

  Subsequently, if it is unnecessary to adjust the deceleration for position control (step S18: NO), the acceleration / deceleration control unit 41 executes deceleration control (position control) with the deceleration for position control calculated in step S14. (Step S20). When the position control deceleration is adjusted (step S18: YES), deceleration control (position control) is executed using the adjusted position control deceleration (step S20).

  As a result, the position control is performed at the position control deceleration with the margin set, so that the stability in the positioning operation of the motor 11a is improved. Further, by securing a margin in advance according to the position control time, the motor 11a always stops at the stop position, so that the reliability in the positioning operation of the motor 11a is improved. Furthermore, since it is not driven beyond the set position control time, unexpected waste does not occur in the time until stopping.

  While the position is controlled, the position information is acquired by the position information acquisition unit 32, and various state information is calculated by the motor state calculation unit 33 (step S21), and the processing from step S18 is performed until the positioning is completed. Repeated (step S22). When the positioning completion determination unit 42 determines that the positioning of the motor 11a has been completed (step S22: YES), this sequence is terminated while the stop position is kept.

[2] Regarding the second mode When the second mode is executed, the initial speed of the motor 11a is extremely low or stopped as shown in FIG. Therefore, as shown in FIG. 16, the acceleration / deceleration control unit 41 first starts acceleration control of the motor 11a with the maximum torque (step S31). At this time, since the difference value from the current position to the stop position is equal to or greater than the minimum inertia measurement distance (step S8: YES), even when accelerating and decelerating at the maximum torque, stop at the shortest distance from the point when the calculation of inertia is completed. It is guaranteed that it can stop in position.

  While accelerating with the maximum torque, the position information acquisition unit 32 acquires the position information, and the motor state calculation unit 33 calculates various state information (step S32), and repeats until the maximum acceleration is calculated (step S33). Thereby, the maximum acceleration in consideration of the influence of the inertia actually generated on the rotating shaft of the motor 11a is calculated. As will be described later, since the maximum acceleration is calculated during acceleration with the maximum torque, optimum acceleration / deceleration is always possible for each of the workpieces having different inertias.

  When the maximum acceleration is calculated (step S33: YES), the position control deceleration calculation unit 36 calculates the position control deceleration by multiplying the maximum acceleration by the margin setting ratio (step S34). At this time, since the torque during acceleration and deceleration is the same (maximum), the maximum acceleration can be used as the maximum deceleration. In addition, by setting an appropriate margin setting ratio, a deceleration for position control is calculated so that the motor 11a can surely stop stably.

  Subsequently, the first maximum speed calculation unit 39 performs the drive control with the initial speed, the maximum acceleration, the position control deceleration, the difference value, the margin setting ratio, and the position control deceleration. The speed at which the sum of the acceleration time at the maximum acceleration, the deceleration time at the maximum deceleration, and the position control time is minimized based on the position control time set as Is calculated as the first maximum speed to be switched to (step S35).

  Further, the switching speed calculation unit 37 determines the moving distance and the position control deceleration at the maximum deceleration based on the maximum deceleration, the first control speed, the margin setting ratio, the position control time, and the difference value. The speed that minimizes the sum of the movement distances at is calculated as the second control speed (step S36). As a result, the optimum timing for switching the drive control of the motor 11a from the speed control to the position control is specified so that the motor 11a can be stopped at the stop position with the smallest number of rotations.

  In the present embodiment, the calculation of the second control speed uses two margin parameters, the margin setting ratio and the position control time. For this reason, even if there is a measurement error or disturbance due to the position detection means 11b, it can be stably controlled, and it is necessary to rotate it one turn without being positioned at the stop position, or to reversely rotate without preventing overshoot. There is no. In addition, the setting values of the margin parameters do not need to be changed depending on the work, and are intuitive and easy to set and adjust.

  Subsequently, while accelerating at the maximum torque, the position information acquisition unit 32 acquires position information, and the motor state calculation unit 33 calculates various state information (step S37), and the current speed of the motor 11a is the first speed. The process is repeated until the maximum speed is reached (step S38). Then, while the speed of the motor 11a is slower than the first maximum speed (step S38: NO), acceleration control is performed with the maximum torque. For this reason, the acceleration time at the maximum torque is ensured as much as possible, and the vehicle is accelerated quickly before switching to the deceleration control, so the time until the positioning is completed is shortened.

  On the other hand, when the speed of the motor 11a reaches the first maximum speed (step S38: YES), the acceleration / deceleration control unit 41 switches from acceleration control to deceleration control and falls below the second control speed (step S39: NO). Decelerate with the maximum torque (step S43). Thereafter, when the speed of the motor 11a falls below the second control speed (step S39: YES), the position control deceleration adjusting unit 38 determines whether or not the position control deceleration adjustment is necessary (step S40). . If adjustment is necessary (step S40: YES), the position control deceleration adjustment unit 38 calculates and adjusts a new position control deceleration (step S41).

  As a result, even if a position control deceleration that cannot be stopped at the stop position due to a measurement error of the position detection means 11b is set, a margin is secured by the position control time. Position control is performed during the position control time. Therefore, based on the latest position information, the position control deceleration is adjusted as appropriate so that the vehicle can be reliably stopped at the stop position.

  Subsequently, if it is not necessary to adjust the deceleration for position control (step S40: NO), the acceleration / deceleration control unit 41 executes deceleration control (position control) with the deceleration for position control calculated in step S34. (Step S42). If the position control deceleration is adjusted (step S40: YES), deceleration control (position control) is executed by the adjusted position control deceleration (step S42).

  As a result, the position control is performed at the position control deceleration with the margin set, so that the stability in the positioning operation of the motor 11a is improved. Further, by securing a margin in advance according to the position control time, the motor 11a always stops at the stop position, so that the reliability in the positioning operation of the motor 11a is improved. Furthermore, since it is not driven beyond the set position control time, unexpected waste does not occur in the time until stopping.

  While being decelerated by the position control deceleration (step S42) or decelerating by the maximum torque (step S43), the position information acquisition unit 32 acquires position information and the motor state calculation unit 33. As a result, various state information is calculated (step S44), and the processing from step S39 is repeated until the positioning is completed (step S45: NO). When the positioning completion determination unit 42 determines that the positioning of the motor 11a has been completed (step S45: YES), this sequence is terminated while the stop position is kept.

[3] Third Mode When the third mode is executed, the initial speed of the motor 11a exists in the low speed range from the vicinity of the base rotational speed as shown in FIG. 17, and the current position is stopped. Very close to location. For this reason, as shown in FIG. 18, the acceleration / deceleration control unit 41 first starts acceleration control of the motor 11a with the set acceleration (step S51). As a result, the motor 11a is not accelerated excessively, and is accelerated to a speed at which it can be stably stopped at the shortest distance.

  Along with the start of acceleration at the set acceleration, the second maximum speed calculation unit 40 calculates a second maximum speed for switching the motor drive control from the acceleration control to the deceleration control based on the set acceleration and the difference value (step S52). . Then, the position information acquisition unit 32 acquires the position information, and the motor state calculation unit 33 calculates various state information (step S53), and the process is repeated until the current speed of the motor 11a becomes equal to or higher than the second maximum speed ( Step S54).

  When the speed of the motor 11a reaches the second maximum speed (step S54: YES), the acceleration / deceleration control unit 41 switches from acceleration control to deceleration control and decelerates at the set acceleration until the positioning is completed (step S55). . As a result, even when the current position is very close to the stop position, it is possible to stop at the shortest possible distance without making another round.

  While being decelerated at the set acceleration, position information is acquired by the position information acquisition unit 32, and various state information is calculated by the motor state calculation unit 33 (step S56), and from step S55 until the positioning is completed. The process is repeated (step S59: NO). When the positioning completion determination unit 42 determines that the positioning of the motor 11a has been completed (step S59: YES), the present sequence is terminated while maintaining the stop position.

According to the present embodiment as described above, the following effects can be obtained.
1. Even from a state where the motor is rotating at a relatively low speed or a state where it is stopped, the motor can be quickly and reliably stopped at a predetermined stop position with as few revolutions as possible.
2. In the first mode and the second mode, the second control speed using the two margin parameters, the margin setting ratio and the position control time, is used as the switching timing, so that it is always stable even if there is an influence of measurement error or disturbance. Can be positioned at the stop position.
3. The margin setting ratio and the position control time in the first mode and the second mode do not need to be changed depending on the workpiece, and are intuitive and can be easily set and adjusted.
4). In the first mode and the second mode, since the position control deceleration can be adjusted in the position control, even if there is a measurement error or the like, it is possible to reliably stop at the stop position.
5. In the third mode, even when the current position is very close to the stop position, it is possible to stop at the shortest possible distance without making another round.
6). By using the maximum decelerable speed, it is possible to determine whether the control is performed in the first mode, the second mode, or the third mode.
7). By using the minimum inertia measurement distance, it is possible to determine whether the control is performed in the second mode or the third mode.
8). By using the first maximum speed, the sum of the acceleration time at the maximum acceleration, the deceleration time at the maximum deceleration, and the position control time can be minimized in the second mode.
9. By using the second maximum speed, the motor drive control can be switched from the acceleration control to the deceleration control at an optimal timing in the third mode.

  When the operation of the motor drive control device 1 according to the present invention is compared with the operation of Patent Document 1 described above, when there is no error and it can be stopped at the stop position as theoretically, Patent Document 1 is better. There may be cases where it can be stopped quickly. However, in reality, as shown in FIG. 19, in Patent Document 1, since deceleration is performed while maintaining a deceleration close to the maximum deceleration even in a low speed region, in many cases, the vehicle stops at a stop position due to a measurement error or the like. It cannot be done, and one more rotation is required.

  On the other hand, according to the operation of the motor drive control device 1 according to the present invention, as described above, since the motor is decelerated with the maximum torque up to the second control speed, the time until stopping is shortened. In addition, at the second control speed or less, the vehicle is highly stable because it decelerates at a position control deceleration with a margin, and the position control is performed at least during the position control time, so that it can always stop at the stop position. It is effective and a realistic and ideal control result can be obtained.

  The motor drive control device 1 and the machine tool 11 including the motor drive control device 1 according to the present invention are not limited to the above-described embodiment, and can be changed as appropriate.

  For example, in the above-described embodiment, the motor drive control device 1 is realized as one function of the numerical control device, but is not limited to this configuration. That is, the motor drive control device 1 may be provided independently of the numerical control device.

DESCRIPTION OF SYMBOLS 1 Motor drive control apparatus 1a Motor drive control program 2 Memory | storage means 3 Arithmetic processing means 10 Host controller 11 Machine tool 11a Motor 11b Position detection means 21 Program storage part 22 Setting condition storage part 31 Setting condition acquisition part 32 Position information acquisition part 33 Motor State calculation unit 34 Maximum deceleration possible speed calculation unit 35 Inertia measurement minimum distance calculation unit 36 Position control deceleration calculation unit 37 Switching speed calculation unit 38 Position control deceleration adjustment unit 39 First maximum speed calculation unit 40 Second maximum speed Calculation unit 41 Acceleration / deceleration control unit 42 Positioning completion determination unit

Claims (6)

A motor drive control device for controlling the drive of a motor,
A motor state calculation unit that calculates a current value of the motor, acceleration or deceleration of the motor, and a difference value between the current position and the stop position based on the position information of the motor detected by the position detection unit;
A maximum decelerable speed calculating unit that calculates the maximum decelerable speed that is the minimum value of the speed at which the motor can be stably stopped even if the motor is decelerated and controlled with the maximum torque;
An inertia measurement minimum distance calculation unit for calculating an inertia measurement minimum distance that is a minimum value of a moving distance necessary for measuring the inertia when the inertia is minimum;
When the initial speed at the start of the drive control of the motor is less than the maximum decelerable speed and the difference value is equal to or greater than the minimum inertia measurement distance, the motor is accelerated by the maximum torque and then decelerated by speed control and position control. Run 2 mode,
When the initial speed is less than the maximum decelerable speed and the difference value is smaller than the minimum inertia measurement distance, the set acceleration is accelerated after accelerating with a set acceleration smaller than the maximum acceleration when accelerating with the maximum torque. An acceleration / deceleration control unit that executes a third mode of decelerating at
A motor drive control device. When the acceleration / deceleration control unit executes the second mode,
A position control deceleration calculating unit that calculates a position control deceleration by multiplying a margin setting ratio by the maximum deceleration of the motor;
Position control set as the minimum value of drive control with the initial speed, the maximum acceleration, the position control deceleration, the difference value, the margin setting ratio, and the position control deceleration Based on the time, the motor drive control is switched from acceleration control to deceleration control for the speed at which the sum of the acceleration time at the maximum acceleration, the deceleration time at the maximum deceleration, and the position control time is minimized. A first maximum speed calculation unit that calculates the first maximum speed;
Based on the maximum deceleration, the first maximum speed, the difference value, the margin setting ratio, and the position control time, the moving distance at the maximum deceleration and the position control deceleration A switching speed calculation unit that calculates a speed at which the sum of the movement distance of the motor and the motor is minimized as a second control speed for switching the drive control of the motor from speed control to position control,
The acceleration / deceleration control unit performs acceleration control with the maximum torque while the speed of the motor is smaller than the first maximum speed, and performs deceleration control with the maximum torque when the speed of the motor reaches the first maximum speed, 2. The motor drive control device according to claim 1, wherein after the motor speed becomes lower than the second control speed, deceleration control is performed with the position control deceleration. 3. When the acceleration / deceleration control unit executes the third mode,
Based on the set acceleration and the difference value, a second maximum speed calculation unit that calculates a second maximum speed for switching the drive control of the motor from acceleration control to deceleration control,
The acceleration / deceleration control unit performs acceleration control at the set acceleration while the motor speed is smaller than the second maximum speed, and performs deceleration control at the set acceleration when the motor speed reaches the second maximum speed. The motor drive control device according to claim 1 or 2. The motor drive control device according to any one of claims 1 to 3, wherein the inertia measurement minimum distance calculation unit calculates the inertia measurement minimum distance using the following equation (2).
S _min = a _max (2T _i ² + XT ² −X ² T ² ) / 2 + ω ₀ T _i (2)
However, each symbol represents the following.
ω ₀ : Initial speed a _max : Maximum set acceleration X: Margin setting ratio T _i : Time required for measuring inertia T: Position control time The first maximum speed calculation unit calculates the first maximum speed ω _{max1 according} to the following formula (5) using the minimum value of the rotation speed n required until the motor satisfying the following formula (6) stops. The motor drive control device according to claim 2;
ω _max1 = √ [{ω ₀ ² −a ₁ ² T ² X (1−X)} / 2 + a ₁ (L + 2πn)] (5)
n ≧ [[ω ₀ ² + a ₁ ² T ² X (1-X)] / 2a ₁ −L] / 2π Formula (6)
However, each symbol represents the following.
ω ₀ : Initial speed a ₁ : Maximum acceleration (maximum deceleration)
n: Number of rotations required until the motor stops L: Difference value between the current position and the stop position X: Margin setting ratio T: Position control time   A machine tool comprising the motor drive control device according to any one of claims 1 to 5.

Images