JP6490520B2 - Motor drive control device and machine tool equipped with the same - Google Patents

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, when a motor used in a machine tool or the like is positioned from a rotating state to a predetermined stop position (angle), a sequence in which the control mode is switched to position control and then stopped after being decelerated at maximum torque by speed control. It has been adopted. 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. 10, if the switching timing to the 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 increased. 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. 11, when the inertia is small, the deceleration at the time of deceleration with the maximum torque is large, and as shown in FIG. 12, when the inertia is large, the deceleration at 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. 13, 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.

  The present invention has been made to solve such problems, and by optimizing the timing for switching from speed control to position control, the motor can be quickly and reliably set to a predetermined speed with as few revolutions as possible. It is an object of the present invention to provide a motor drive control device that can be stopped at a stop position and a machine tool including the motor drive control device.

  The motor drive control device according to the present invention is a motor drive control device that controls the drive of the motor, and based on the position information of the motor detected by the position detection means, the current speed of the motor, the maximum of the motor A motor state calculation unit that calculates a deceleration and a difference value between the current position and the stop position, and a position control deceleration that calculates a deceleration for position control by multiplying the maximum deceleration of the motor by a margin setting ratio Driving with the calculation unit, the maximum deceleration, the first control speed indicating the motor speed at the timing when the maximum deceleration is calculated, the difference value, the margin setting ratio, and the position control deceleration Based on the position control time set as the minimum value of the control time, the speed at which the sum of the travel distance at the maximum deceleration and the travel distance at the position control deceleration is minimized A switching speed calculation unit that calculates the motor drive control as a second control speed for switching from speed control to position control, and performs deceleration control with maximum torque while the motor speed is greater than the second control speed. And a deceleration control unit that executes deceleration control with the position control deceleration after the speed of the motor becomes lower than the second control speed.

Further, as one aspect of the present invention, the switching speed calculation unit uses the minimum value of the rotation speed n required until the motor satisfying the following expression (2) stops, and The two control speeds ω ₂ may be calculated.
ω ₂ = √ [{X / (1-X)} · {2a ₁ (L + 2πn) −ω ₁ ² }] Formula (1)
n ≧ [[ω ₁ ² + {(1−X) / X} (a ₁ XT) ² ] / 2a ₁ −L] / 2π Formula (2)
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

  Furthermore, as one aspect of the present invention, while the deceleration control unit performs deceleration control of the motor at a speed smaller than the second control speed, the deceleration for position control is performed based on the latest position information. You may have the deceleration control part for position control to adjust.

  A machine tool according to the present invention includes the motor drive control device according to any one of claims 1 to 3.

  According to the present invention, by optimizing the switching timing from the speed control to the position control, the motor can be stopped at a predetermined stop position quickly and surely with as few revolutions as possible.

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. 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. It is a flowchart which shows operation | movement of the motor drive control apparatus of this embodiment. 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 can set a stop position, a positioning condition, a stop determination speed, a first control speed, a margin setting ratio, and a position control time as setting conditions to be output to the motor drive control device 1. It is configured.

  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 a position control deceleration below a 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 provided. 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 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. The machine tool 11 includes a motor 11a that is driven and controlled based on a drive signal supplied from the motor drive control device 1, and position detection means 11b such as a rotary encoder that detects position information (rotational angle position) of the motor 11a. have. 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 and when the arithmetic processing means performs arithmetic processing. The storage means 2 that functions as a working area and the 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 are provided. doing. 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. Then, the arithmetic processing means 3 executes the motor drive control program 1a to cause the motor drive control device 1 as a computer to function as each component described later. In the present embodiment, the motor drive control program 1a includes a speed control mode for controlling the motor 11a at a constant speed and a position control mode for positioning the rotary shaft at a desired stop position. I have.

  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 the present embodiment, as described above, the stop position, the positioning condition, the stop determination speed, the first control speed, the margin setting ratio, and the position control time are set in advance by the host controller 10, These setting conditions are 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 deceleration determination unit 34, position control deceleration calculation unit 35, switching speed calculation unit 36, positioning completion determination unit 37, The position control deceleration adjusting unit 38 and the deceleration control unit 39 function. 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 acquires a setting condition including a stop position, a positioning condition, a stop determination speed, a first control speed, a margin setting ratio, and a position control time output from the host controller 10, 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 detected by the position detection unit 11 b and outputs the position information to the motor state calculation unit 33.

  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 the position information once as a current speed of the motor 11a, and calculates a value obtained by differentiating the position information twice as a deceleration of the motor 11a. 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 deceleration determination unit 34 determines a maximum deceleration that is the maximum value of the deceleration of the motor 11a. In the present embodiment, the maximum deceleration determination unit 34 determines whether the current speed of the motor 11 a calculated by the motor state calculation unit 33 is slower than the first control speed stored in the setting condition storage unit 22. Is constantly monitored. Then, immediately after the current speed becomes slower than the first control speed, the calculated deceleration is determined as the maximum deceleration.

  The position control deceleration calculating unit 35 calculates a position control deceleration which is a deceleration used during position control. In the present embodiment, the position control deceleration calculation unit 35 acquires the maximum deceleration of the motor 11 a determined by the maximum deceleration determination unit 34 and acquires the margin setting ratio from the setting condition storage unit 22. The position control deceleration calculating unit 35 calculates the position control deceleration by multiplying the maximum deceleration by the margin setting ratio.

  The switching speed calculation unit 36 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. As shown in FIG. 5, 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 36 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 36 determines the maximum deceleration determined by the maximum deceleration determination unit 34, the first control speed, the margin setting ratio, and the position control time stored in the setting condition storage unit 22. And the speed at which the sum of the movement distance at the maximum deceleration and the movement distance at the position control deceleration is minimized is calculated as the second control speed based on the difference value calculated by the motor state calculation unit 33. It is supposed to be.

Here, the calculation method of the second control speed will be specifically described. As shown in FIG. 6, from the first control speed ω ₁ to the second control speed ω ₂ , the vehicle is decelerated over the time t ₁ at 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 (1) 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 }] Formula (1)

Here, in order for the route (root) in the above formula (1) 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 (2) 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 (2)

That is, the switching speed calculation unit 36 calculates the second control speed ω ₂ by the following formula (1) using the minimum value of the rotation speed n necessary until the motor 11a satisfying the following formula (2) stops. It is like that.
ω ₂ = √ [{X / (1-X)} · {2a ₁ (L + 2πn) −ω ₁ ² }] Formula (1)
n ≧ [[ω ₁ ² + {(1−X) / X} (a ₁ XT) ² ] / 2a ₁ −L] / 2π Formula (2)
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 positioning completion determination unit 37 determines whether or not the positioning of the motor 11a has been completed. In the present embodiment, the positioning completion determination unit 37 refers to the stop position, the positioning condition, and the stop determination speed stored in the setting condition storage unit 22, and 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 37 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. .

  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 present embodiment, the position control deceleration adjustment unit 38 is used for position control based on the latest position information while the deceleration control unit 39 performs deceleration control of the motor 11a at a speed smaller than the second control speed. Adjust the deceleration.

Specifically, as shown in FIG. 7, at the time when the small speed omega ₃ than the second control speed is decelerating controls the motor 11a, multiplied by t ₃ the remaining moving distance S ₃ to the stop position Time 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 39.

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%.

The deceleration control unit 39 outputs a drive signal to the motor 11a and executes deceleration control. In the present embodiment, the deceleration control unit 39 constantly monitors the current speed of the motor 11 a calculated by the motor state calculation unit 33. Then, as shown in FIG. 3, while the speed of the motor 11a is larger than the second control speed, deceleration control (speed control) is performed with the maximum torque, and after the speed of the motor 11a becomes smaller than the second control speed. Is configured to execute deceleration control (position control) with the position control deceleration calculated by the position control deceleration calculation unit 35. In the present embodiment, when the position control deceleration adjustment unit 38 adjusts the position control deceleration, the deceleration control unit 39 performs deceleration control ( ₃₎ using the position control deceleration a ₃ after the adjustment. Position control) is executed.

  Next, the operation of the motor drive control device 1 of the present embodiment will be described with reference to the flowchart of FIG.

  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 including the condition, stop determination speed, first control speed, margin setting ratio, and position control time 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, and the processes of subsequent steps S2 to S14 are repeated at a predetermined cycle until the positioning is completed.

  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 performs the current speed and deceleration of the motor 11a based on the position information. And a difference value between the current position and the stop position is calculated (step S3). Thereby, the current state of the motor 11a is grasped.

  Subsequently, the maximum deceleration determination unit 34 monitors whether or not the current speed of the motor 11a is slower than the first control speed (step S4). Then, immediately after the current speed becomes slower than the first control speed (step S4: YES), if the maximum deceleration has not yet been determined (step S5: NO), the deceleration calculated in step S3 Is determined as the maximum deceleration (step S6).

  Thereby, the maximum deceleration of the motor 11a is specified only by setting a base rotation speed (first control speed) specific to the motor 11a to be controlled. As will be described later, since the maximum deceleration is determined during the deceleration with the maximum torque, the optimum deceleration can always be performed for each of the workpieces having different inertias (rotational inertia moments).

  On the other hand, when the current speed of the motor 11a is equal to or higher than the first control speed (step S4: NO), the process proceeds to step S14 described later, and deceleration control (speed control) is executed by the deceleration control unit 39 with the maximum torque. Is done. In step S5, if the maximum deceleration has already been determined (step S5: YES), the process proceeds to step S9 described later.

  When the maximum deceleration is determined in step S6, the position control deceleration calculation unit 35 calculates the position control deceleration by multiplying the maximum deceleration by the margin setting ratio (step S7). 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 36 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 S8). 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.

  Next, the positioning completion determination unit 37 determines whether the positioning of the motor 11a is completed based on the stop position, the positioning condition, the stop determination speed, the position information (current position), and the current speed (step S9). . As a result of the determination, when the positioning is completed (step S9: YES), this sequence is terminated while the stop position is kept (step S15).

  On the other hand, if the positioning has not been completed (step S9: NO), the deceleration control unit 39 monitors whether or not the current speed of the motor 11a is slower than the second control speed (step S10). Then, while the speed of the motor 11a is larger than the second control speed (step S10: NO), deceleration control (speed control) is performed with the maximum torque (step S14). 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 is smaller than the second control speed (step S10: YES), the position control deceleration adjusting unit 38 determines whether or not the position control deceleration needs to be adjusted (step S11). ). If adjustment is necessary (step S11: YES), the position control deceleration adjusting unit 38 calculates and adjusts a new position control deceleration (step S12).

  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 the deceleration for position control is not adjusted (step S11: NO), the deceleration control unit 39 executes deceleration control (position control) with the deceleration for position control calculated in step S7 (step S13). ). Further, when the position control deceleration is adjusted (step S11: YES), deceleration control (position control) is executed using the adjusted position control deceleration (step S13).

  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.

  The processes in steps S2 to S14 are repeated at a predetermined cycle unless it is determined in step S9 that the positioning has been completed.

According to the present embodiment as described above, the following effects can be obtained.
1. By optimizing the switching timing from the speed control to the position control, the motor 11a can be stopped at a predetermined stop position quickly and reliably with as few revolutions as possible.
2. Since the second control speed using the two margin parameters, the margin setting ratio and the position control time, is used as the switching timing, even if there is an influence of measurement error or disturbance, it is possible to always stably position the stop position. .
3. The margin setting ratio and the position control time do not need to be changed depending on the workpiece, and are intuitive and can be easily set and adjusted.
4). In position control, since the deceleration for position control can be adjusted, even if there is a measurement error or the like, it is possible to reliably stop at the stop position.

  Further, 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, if there is no error and the motor 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. 9, 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 section 34 Maximum deceleration determination section 35 Position control deceleration calculation section 36 Switching speed calculation section 37 Positioning completion determination section 38 Position control deceleration adjustment section 39 Deceleration control section

Claims (4)

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, a 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 position control deceleration calculating unit that calculates a position control deceleration by multiplying a margin setting ratio by the maximum deceleration of the motor;
The maximum deceleration, the first control speed indicating the motor speed at the timing at which the maximum deceleration is calculated, the difference value, the margin setting ratio, and the time for drive control with the position control deceleration. Based on the position control time set as the minimum value, 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, and the drive control of the motor is speeded up. A switching speed calculation unit for calculating as a second control speed for switching from control to position control;
While the motor speed is higher than the second control speed, the deceleration control is performed with the maximum torque, and after the motor speed becomes lower than the second control speed, the deceleration control is performed with the position control deceleration. A deceleration control unit to be executed;
A motor drive control device. The switching speed calculation unit calculates the second control speed ω _{2 according} to the following formula (1) using the minimum value of the rotation speed n required until the motor satisfying the following formula (2) stops. The motor drive control device according to claim 1;
ω ₂ = √ [{X / (1-X)} · {2a ₁ (L + 2πn) −ω ₁ ² }] Formula (1)
n ≧ [[ω ₁ ² + {(1−X) / X} (a ₁ XT) ² ] / 2a ₁ −L] / 2π Formula (2)
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   A position control deceleration adjustment unit that adjusts the position control deceleration based on the latest position information while the deceleration control unit performs deceleration control of the motor at a speed smaller than the second control speed. The motor drive control device according to claim 1, comprising:   A machine tool comprising the motor drive control device according to any one of claims 1 to 3.

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