JP5925066B2 - Motor drive control device - Google Patents

Description

  The present invention relates to a motor drive control device that drives and controls a motor that drives a machine tool.

  In general, the rotation axis control includes speed control used when rotating the motor at a constant speed and position control (positioning control) used when matching the rotation axis angle (phase) to a predetermined angle.

  When controlling a spindle motor for a machine tool, rotation axis control is performed while switching a control system (speed control and position control) according to a requested operation. For this reason, when switching from speed control to position control, it is necessary to generate a deceleration pattern in which the commanded angle (phase) matches the motor angle (phase) and then decelerates to speed 0.

  For example, in the technique disclosed in Patent Document 1, a speed for switching from speed control to position control is defined in advance. Then, a position command after switching is generated using the acceleration immediately before reaching the specified speed, and further a speed pattern until deceleration stop is generated.

Japanese Patent No. 4099503

  However, in the above prior art, since the acceleration immediately before reaching the specified speed is not necessarily the maximum acceleration that the motor can output, the time required to decelerate and stop to the specified phase is not the shortest. There was a problem.

  Further, in a spindle motor for machine tools and the like, in order to perform field-weakening control and the like, the outputable acceleration is reduced, thereby realizing high-speed rotation. For this reason, when decelerating from the high speed range, it is necessary to switch from the speed control system to the position control system after decelerating to a low speed where the acceleration is constant. As a result, there is a problem that the time until deceleration stop becomes longer.

  If the switching speed from the speed control system to the position control system is not set appropriately, the time until deceleration stop is unnecessarily long. For this reason, the switching speed needs to be set in advance according to the motor characteristics, and there is a problem that the setting is complicated.

  The present invention has been made in view of the above, and even when the motor output characteristic changes according to the speed, the switching from the speed control system to the position control system is made according to the acceleration that the motor can output. An object of the present invention is to obtain a motor drive control device that can be easily minimized.

In order to solve the above-described problems and achieve the object, the present invention provides a motor drive control device that drives and controls a motor based on a position command, and a difference between the position command and a position detection value detected from the motor. A control input to the motor is calculated based on the positional deviation and a control input calculation unit that sends the calculated control input to the motor side, and the control input calculated by the control input calculation unit is a predetermined control input. Based on the control input restriction unit that restricts to a limit value or less, the position detection value and the control input after the limit , the maximum acceleration that the motor can output is calculated, and the maximum acceleration and the position detection value are calculated. Based on the ratio between the required deceleration distance and the positional deviation, and calculates the required deceleration distance that is the minimum distance required to decelerate and stop at the maximum acceleration. A reference control input calculation unit that calculates a reference control input that is a desired value; and a position deviation shaping unit that corrects the position deviation so that the control input matches the reference control input. The control input is calculated based on the corrected position deviation, and the control input restriction unit outputs the control input after the restriction to the motor and the reference control input calculation unit .

  According to the present invention, it is possible to easily minimize the movement time according to the acceleration that can be output by the motor, and to easily switch from the speed control system to the position control system. Play.

FIG. 1 is a block diagram illustrating a configuration of the motor drive control device according to the first embodiment. FIG. 2 is a flowchart showing a calculation processing procedure according to the first embodiment of the reference control input. FIG. 3 is a flowchart showing a calculation processing procedure according to the second embodiment of the reference control input. FIG. 4 is a diagram for explaining the relationship between speed and acceleration characteristics when the motor exhibits different acceleration characteristics depending on the speed.

  Hereinafter, a motor drive control device according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to these embodiments.

Embodiment 1 FIG.
First, the entire control process of the motor drive control device according to the first embodiment will be described, and then the configuration and operation of each element of the motor drive control device will be described. FIG. 1 is a block diagram illustrating a configuration of the motor drive control device according to the first embodiment. The motor drive control device 1 is a device that drives and controls a spindle motor (hereinafter referred to as a motor 3) that drives a machine tool (not shown).

  The motor drive control device 1 is connected to a motor 3, and a position detector 4 that detects a drive position is attached to the motor 3. The motor drive control device 1 is connected to the position detector 4 and the position command generation device 2. The motor drive control device 1 controls the drive of the motor 3 within the range of the control input restriction based on the position command X output from the position command generation device 2.

  The position command X is a command for moving the servo motor of each axis included in the motor 3 to a predetermined position, and is generated by the position command generation device 2 and output to the motor drive control device 1. The position detection value B is the position of the servo motor of each axis included in the motor 3, is detected by the position detector 4, and is output to the motor drive control device 1.

  The position deviation DRP is the difference between the position command X and the position detection value B. The corrected position deviation C is obtained by correcting the position deviation DRP so that the control input to the motor 3 (drive signal value for driving and controlling the motor 3) does not become an excessive value (range). When it is not necessary to correct the position deviation DRP, the motor drive control device 1 sets the position deviation DRP as the corrected position deviation C.

  The control input U is a control signal for controlling the motor 3. The post-limit control input D is obtained by limiting the control input U to a predetermined control input limit value or less, and is used as a control signal for controlling the motor 3. The reference control input TLMT is a set value for calculating the corrected position deviation C.

  The motor drive control device 1 calculates a corrected position deviation C based on the position command X output from the position command generation device 2 and the position detection value B that is an output signal from the position detector 4. Further, the motor drive control device 1 calculates the control input U using the corrected position deviation C, and calculates the post-limit control input D using the control input U.

  The motor drive control device 1 includes a position deviation shaping unit 11, a reference control input calculation unit 12, a control input calculation unit 13, and a control input restriction unit 14. The motor drive control device 1 calculates a position deviation DRP that is the difference between the position command X and the position detection value B, and sends the calculated position deviation DRP to the position deviation shaping unit 11. A position command X, a reference control input TLMT, and a position detection value B are input to the position deviation shaping unit 11.

  The position deviation shaping unit 11 basically requires the reference control input TLMT, whereas the position command X and the position detection value B are not required depending on the calculation method (internal structure) in the control input calculation unit 13. There are cases where it is necessary and cases where it is necessary.

  The position deviation shaping unit 11 uses a relational expression between the control input U calculated by the control input calculation unit 13 and the position deviation (corrected position deviation) DRP based on at least the reference control input TLMT. A position deviation amount (corrected position deviation C) for matching with the reference control input TLMT is calculated. The position deviation shaping unit 11 outputs the calculated corrected position deviation C to the control input calculation unit 13.

  The control input calculation unit 13 has an inverse model of the position deviation shaping unit 11 and calculates a control input U to the motor 3 based on the corrected position deviation C. The control input calculation unit 13 includes a general feedback compensator (feedback controller). The control input calculation unit 13 includes, for example, a proportional compensator (P compensator) and a proportional-integral compensator (PI compensator). As described above, the control input calculation unit 13 calculates the control input U to the motor 3 by performing integral operation, differential operation, and four arithmetic operations on the position deviation (corrected position deviation C).

  Therefore, the calculation method of the control input U is not specified and is arbitrary. The control input calculation unit 13 may be configured by a control system having a minor loop (inner loop) inside, or may be configured by a control system in which a speed control system is nested inside the position control system. Good. The control input calculation unit 13 sends the calculated control input U to the control input restriction unit 14.

  The control input restriction unit 14 is a filter that restricts the control input U from the control input calculation unit 13 based on a preset control input restriction value. The control input limit value is set in advance in the control input limit unit 14 in accordance with the characteristics of the actuator such as the motor 3 and the mechanical system (for example, the allowable force of the speed reducer).

  When the control input U exceeds a predetermined control input limit value, the control input limiter 14 clamps the control input U with a predetermined control input limit value, and sends the clamped post-limit control input D to the motor 3. Output as drive signal. For example, when the control input limit value is TLMT0, a control input U equal to or greater than TLMT0 is output to the motor 3 as a post-limit control input D = TLMT0. The control input restriction unit 14 sends the calculated post-restriction control input D to the motor 3 and the reference control input calculation unit 12.

  The control input limit value may be a fixed value set in advance according to the characteristics of the motor 3, or may be a value calculated sequentially from feedback information to be controlled. Further, a plurality of control input limit values may be prepared in advance, and the control input limit unit 14 may select one of the plurality of control input limit values according to the acceleration / deceleration state of the motor 3. Further, the control input limiting unit 14 uses a positive control input limit value when the acceleration of the motor 3 is positive, and uses a negative control input limit value when the acceleration is negative. Also good.

  The reference control input calculator 12 calculates the reference control input TLMT based on the position detection value B, the post-limit control input D that is an output signal of the control input limiter 14, and the position deviation DRP. The reference control input calculation unit 12 sends the calculated reference control input TLMT to the position deviation shaping unit 11.

  As described above, the control input calculation unit 13 calculates the control input U from the corrected position deviation C, whereas the position deviation shaping unit 11 calculates the reference control input TLMT (the control input calculation unit 13 of the control input calculation unit 13). The corrected position deviation C (input signal of the control input calculation unit 13) is calculated from the output signal). Therefore, when the control input calculation unit 13 has an integral characteristic or an inner loop (minor loop), the position deviation shaping unit 11 considers the influence of the integral characteristic and the influence of the minor loop, and then uses the reference control input TLMT. The corrected position deviation C is calculated.

Next, a calculation processing example of the corrected position deviation C will be described. Processing p1 to processing p3 shown below is a calculation processing example of the corrected position deviation C.
(Process p1)
For example, when the control input calculation unit 13 is a proportional compensator (P compensator), the position deviation shaping unit 11 can calculate the corrected position deviation C using the reference control input TLMT. The input / output relationship of the control input calculation unit 13 in this case is expressed by the following equation (1) using the control input U, the proportional gain KP, and the position deviation DRP.
U = KP × DRP (1)

At this time, the position deviation DRP ′ such that the control input U becomes the reference control input TLMT can be calculated using the control input U that is the output of the control input calculation unit 13 and the proportional gain KP. Become.
DRP ′ = TLMT / KP (2)

(Process p2)
When the control input calculation unit 13 is a proportional-integral compensator (PI compensator), the position deviation shaping unit 11 uses the reference control input TLMT, the position command X, and the position detection value B to calculate the corrected position deviation C. Perform the calculation. In this case, the input / output relationship of the control input calculation unit 13 is expressed by the following equation (3) using the time integral value (cumulative value) DRP2 of the control input U, the proportional gain KP, the position deviation DRP, the integral gain KI, and the position deviation DRP. )
U = KP × DRP + KI × DRP2 (3)

At this time, the position deviation DRP ′ for the control input U to match the reference control input TLMT = TLMT is equal to the corrected position deviation C that is an input of the control input calculation unit 13 as will be described later. Is calculated by subtracting the integral component in the proportional integral compensator (the value obtained by integrating the position deviation signal and multiplying by the integral gain) from the control input U, which is the output of the following equation (4).
DRP ′ = (TLMT−KI × DRP2) / KP (4)
Here, DRP2 is a value calculated by time-integrating (accumulating) the difference (position deviation DRP) between the position command X and the position detection value B.

(Process p3)
The control input calculation unit 13 includes a position control system and a speed control system, and each compensator (controller) includes a position proportional compensator (position P compensator) and a speed proportional integral compensator (speed PI compensation). The position deviation shaping unit 11 calculates the corrected position deviation C using the reference control input TLMT, the position command X, and the position detection value B. In this case, the input / output relationship of the control input calculation unit 13 is as follows: time integral value (accumulated value) of the control input U, the speed proportional gain KV, the proportional gain KP, the position deviation DRP, the speed detection value VFB, the speed integral gain KI, and the speed deviation VDRP. Value) Using VDRP2, the following equation (5) is obtained.
U = KV × (KP × DRP−VFB) + KI × VDRP2 (5)

At this time, the position deviation DRP ′ for the control input U to coincide with the reference control input TLMT takes into account the integral component and the speed detection value of the speed controller from the control input U that is the output of the control input calculator 13. And can be calculated by the following equation (6).
DRP ′ = ((TLMT−KI × VDRP2) / KV + VFB) / KP (6)

Here, the speed deviation VDRP can be expressed by the following relational expression (7). Further, the speed deviation accumulated value VDRP2 can be calculated by time integration of Expression (7). The speed detection value VFB can be calculated by time differentiation of the position detection value.
VDRP = (KP × DRP−VFB) (7)

  Note that information required by the position deviation shaping unit 11 (position deviation accumulated value, speed detection value VFB, speed deviation accumulated value VDRP2, etc.) may be generated by calculation inside the position deviation shaping unit 11 or a control input. An internal signal of the calculation unit 13 may be used.

  FIG. 2 is a flowchart showing a calculation processing procedure according to the first embodiment of the reference control input. When the position command generation device 2 outputs the position command X to the motor drive control device 1, the motor 3 starts its operation. When the motor 3 starts operating, the position detector 4 detects the position of the motor 3 and outputs the detection result to the motor drive control device 1 as a position detection value B.

The reference control input calculation unit 12 calculates the acceleration (FB acceleration) calculated by second-order differentiation (difference) of the position detection value B, which is the output of the position detector 4, and the control input U (control after limitation) to the motor 3. Based on the input D), the maximum acceleration that the motor 3 can output is calculated (step ST10). The maximum acceleration that can be output by the motor 3 can be calculated using the ratio (percentage) of the control input U to the control input limit value. For example, consider a case where the control input limit value to the motor 3 is 120% of the rated current, and the control input U at a certain time is 100% of the rated current of the motor 3. At this time, if the acceleration is A, the maximum acceleration AMAX can be calculated using the following equation (8).
AMAX = A × 120/100 = 1.2 × A (8)

After calculating the maximum acceleration AMAX, the reference control input calculation unit 12 uses the maximum acceleration AMAX and the value of the speed V at this time to calculate the distance required to decelerate and stop from the speed V to the speed 0 (servo motor (Movement distance) is calculated as the deceleration required distance LDCC (step ST20). Specifically, when decelerating from the speed V to the speed 0 with the acceleration AMAX, the reference control input calculation unit 12 calculates the deceleration required distance LDCC using the following equation (9).
LDCC = V × V / (2 × AMAX) (9)

Thereafter, the reference control input calculation unit 12 compares the calculated deceleration required distance LDCC with the position deviation DRP that is an input signal to the control input calculation unit 13, and the position deviation DRP is updated based on the comparison result. It is determined whether or not it is necessary (step ST30). Specifically, the reference control input calculation unit 12 determines the position deviation when the position deviation DRP is smaller than the deceleration required distance LDCC or when the movement amount ROT for one rotation satisfies the relationship of the following expression (10). It is determined that the DRP needs to be updated. On the other hand, the reference control input calculation unit 12 calculates the position deviation DRP when the position deviation DRP is equal to or greater than the deceleration required distance LDCC and when the movement amount ROT for one rotation does not satisfy the relationship of the following equation (10). It is determined that no update is necessary.
DRP> LDCC + ROT (10)

  In other words, the reference control input calculation unit 12 determines that the update of the position deviation DRP is not necessary when LDCC ≦ DRP ≦ LDCC + ROT, and determines that the position deviation DRP needs to be updated otherwise. .

  When the reference control input calculation unit 12 determines that the position deviation DRP needs to be updated (step ST30, Yes), the reference control input calculation unit 12 determines whether the position deviation DRP is smaller than the required deceleration distance LDCC. When the position deviation DRP is smaller than the deceleration required distance LDCC, the reference control input calculation unit 12 adds the movement amount ROT to the position deviation DRP by one rotation until the position deviation DRP becomes equal to or greater than the deceleration required distance LDCC.

Specifically, the reference control input calculation unit 12 calculates N that satisfies the following expression (11).
LDCC <DRP + N × ROT <LDCC + ROT (11)
Then, the reference control input calculation unit 12 updates the position deviation DRP to a new position deviation DRP ″ (DRP ″ = DRP + N × ROT), and updates the distance to the deceleration stop position (deceleration required distance LDCC) (step ST40). ).

  When the movement amount ROT for one rotation satisfies the relationship of Expression (10), the reference control input calculation unit 12 calculates the movement amount ROT for one rotation from the position deviation DRP until the relationship of Expression (11) is satisfied. Subtract in order. Thereby, the reference control input calculation unit 12 calculates N and updates the position deviation DRP to a new position deviation DRP ″ (DRP ″ = DRP−N × ROT). Then, the distance to the deceleration stop position is updated.

  On the other hand, when the reference control input calculation unit 12 determines that the position deviation DRP is not required to be updated (No in step ST30), the reference control input calculation unit 12 sets DRP ″ = DRP (step S50).

In the expression (9), the relationship between the maximum acceleration AMAX and the required deceleration speed LDCC is an inversely proportional relationship. Therefore, using the deceleration required distance LDCC that is the minimum distance required for deceleration and the updated distance to the deceleration stop position (position deviation DRP ″), the deceleration (acceleration) AREF during the fixed position stop control is as follows: Equation (13) can be obtained by using Equation (9) and Equation (12).
AREF = (LDCC / DRP ″) × AMAX (12)
DRP ”= V × V / (2 × AREF) (13)

  Therefore, only by changing the magnitude of the acceleration AREF, the distance (deceleration required distance LDCC) required to decelerate and stop from the speed V to the acceleration AREF is matched with the DRP ″ updated in step ST40 or step ST50. It becomes possible.

  For this reason, the reference control input calculation unit 12 calculates the reference control input TLMT using the deceleration required distance LDCC calculated in step ST20 and the position deviation DRP "updated in step ST40 or step ST50 (step ST60). ).

Specifically, the reference control input calculation unit 12 uses the updated position deviation DRP ″, the deceleration required distance LDCC, and the control input limit value TLMT0 set in the control input limit unit 14 as follows: By (14), the reference control input TLMT = TLMT, which is the output signal of the reference control input calculation unit 12, is calculated.
TLMT = (LDCC / DRP ″) × TLMT0 (14)
As a result, it is possible to automatically minimize the movement time according to the maximum acceleration AMAX that the motor 3 can output.

  When the reference control input calculation unit 12 and the position deviation shaping unit 11 that operate as described above cooperate with each other, the vehicle decelerates at a constant acceleration AREF until it decelerates from the predetermined speed V to the speed 0, and when the speed becomes zero. At the same time, a deceleration pattern in which the position deviation DRP becomes 0 can be generated. For this reason, even when the motor output characteristic of the motor 3 changes according to the speed, the deceleration in the shortest time can be realized according to the acceleration A that the motor 3 can output. In addition, it is not necessary to preset the switching speed from the speed control system to the position control system.

  Note that the motor drive control device 1 may not have the control input restriction unit 14. In this case, the control input U calculated by the control input calculation unit 13 is sent to the motor 3 and the reference control input calculation unit 12.

  In this way, in the motor drive control device 1, the control input calculation unit 13 calculates the control input U to the motor 3 based on the position deviation DRP or the corrected position deviation C, and the motor 3 side (control input calculation unit 13). Send to. Then, the reference control input calculation unit 12 calculates the maximum acceleration AMAX that the motor 3 can output based on the position detection value B and the control input U (post-limit control input D) sent to the motor 3 side, Based on the maximum acceleration AMAX and the position detection value B, a deceleration required distance LDCC, which is the minimum distance required to decelerate and stop at the maximum acceleration AMAX, is calculated. Further, the reference control input calculation unit 12 calculates a reference control input that is a desired value of the control input based on the ratio between the deceleration required distance LDCC and the corrected position deviation C. Then, the position deviation shaping unit 11 calculates the corrected position deviation C by correcting the position deviation DRP so that the control input U matches the reference control input. Further, the control input calculation unit 13 calculates a control input U based on the corrected position deviation C.

  In the motor drive control device 1, the process by the position deviation shaping unit 11, the process by the control input calculation unit 13, the process by the control input restriction unit 14, and the process by the reference control input calculation unit 12 are repeated to control the drive of the motor 3. The

  As described above, according to the first embodiment, since the deceleration pattern is generated from the position deviation DRP and the distance required for deceleration (deceleration required distance LDCC), it is possible to generate the deceleration pattern of the shortest time within the control input limit range. Is possible. Thereby, deceleration in the shortest time becomes possible.

  Further, since the maximum acceleration AMAX is calculated based on the acceleration of the motor 3, even when the control input U to the motor 3 is not the maximum value (when the detected acceleration is not the maximum value), the deceleration using the maximum acceleration is performed. Deceleration pattern generation until stop is possible. For this reason, waste of deceleration time can be eliminated. Further, since the speed pattern can be automatically generated, the time required for setup such as setting of the control system switching speed can be eliminated.

  Therefore, even when the motor output characteristic changes according to the speed, the switching from the speed control system to the position control system can be easily made the shortest according to the maximum acceleration AMAX that the motor 3 can output.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, a deceleration pattern is generated when the maximum acceleration AMAX that can be output by the motor 3 decreases as the speed increases.

  FIG. 3 is a flowchart showing a calculation processing procedure according to the second embodiment of the reference control input. Here, reference control input calculation processing by the reference control input calculation unit 12 of the motor drive control device 1 will be described. In FIG. 3, processes that are the same as or equivalent to the steps shown in FIG. 2 (Embodiment 1) are denoted by the same reference numerals. Here, the description will focus on the features of the second embodiment.

  In the present embodiment, a processing example in the case of calculating a reference control input for the motor 3 when the motor 3 to be controlled is controlled so as to exhibit different acceleration characteristics depending on the speed will be described.

  FIG. 4 is a diagram for explaining the relationship between speed and acceleration characteristics when the motor exhibits different acceleration characteristics depending on the speed. In FIG. 4, the horizontal axis represents speed (rotation speed), and the vertical axis represents acceleration (torque).

  When the motor 3 exhibits different acceleration characteristics depending on the speed, for example, as shown in FIG. 4, a constant torque (acceleration) can be output up to a predetermined rotation speed (base rotation speed NB) regardless of the speed. is there. The motor 3 is controlled so that the output is constant (torque (acceleration) changes in an inverse proportion) at a speed equal to or higher than the base rotational speed (base rotational speed) NB. The acceleration characteristic (torque characteristic) in the motor 3 is a characteristic realized by field-weakening control, and is controlled so that the output is constant at a speed equal to or higher than the base rotational speed NB.

  When the motor 3 exhibits the acceleration characteristics shown in FIG. 4, when the motor 3 starts operating, the position detector 4 detects the position of the motor 3 and sets the detection result as the position detection value B to the motor drive control device 1. Output.

  At this time, the reference control input calculator 12 compares the base rotational speed NB and the speed V, and determines whether or not V <NB (step ST1). When the speed V is less than the base rotation speed NB (step ST1, Yes), the reference control input calculation unit 12 performs the same processing as steps ST10 to ST60 described in FIG. 2 of the first embodiment.

On the other hand, when the speed V is equal to or higher than the base rotation speed NB (step ST1, No), the reference control input calculation unit 12 calculates the maximum acceleration in the constant output region (step ST2). Here, in the constant output region, assuming that the speed V and the torque T, the output PNB in the constant output region satisfies the relationship of the following equation (15).
T = PNB / V (15)

Here, when inertia J is used, the acceleration AMAX is expressed by the following equation (16).
AMAX = PNB / (J × V) (16)
Using this relationship, the maximum acceleration AMAX at the base rotation speed NB or lower can be calculated by the following equation (17) using the speed V in the constant output region and the maximum acceleration AMAX2 at the speed V.
AMAX = (AMAX2 × V) / NB (17)

  Note that the maximum acceleration AMAX2 is the ratio (percentage) of the acceleration in the constant output region and the control input U to the control input limit value to the motor 3 as in the process in step ST10 in FIG. 2 (Embodiment 1). Can be used to calculate.

Thus, the maximum acceleration AMAX that can be output from the motor 3 at the base rotational speed NB or less can be calculated from the acceleration, the speed, and the base rotational speed NB even from the rotational speed that is the base rotational speed NB or higher. For example, when the post-limit control input D is 80% of the control input limit value and the acceleration A at the speed V in the constant output region, the maximum acceleration AMAX2 at the speed V is calculated using the following equation (18). be able to.
AMAX2 = A / 0.8 = 1.25A (18)
As a result, the maximum acceleration AMAX at the base rotation speed NB or lower can be calculated.

  After calculating the maximum acceleration AMAX in the constant output region, the reference control input calculation unit 12 calculates the distance (servo motor movement distance) required to decelerate and stop from a rotational speed equal to or higher than the base rotational speed NB (step ST3). ). Here, a method of calculating the movement distance from the rotation speed of the base rotation speed NB to the deceleration stop will be described.

At a rotational speed that is equal to or higher than the base rotational speed NB, the speed and acceleration are in the relationship of equation (16). In this case, when the vehicle is decelerated with the acceleration AMAX from the speed V at time T to the speed V1 at time T1, the time function of the deceleration speed can be expressed by the following equation (19).
V1 = √ (2 × (PNB / J) × (T1-T) + V ^ 2) (19)

Here, when the equation (19) is time-differentiated, the relationship of the following equation (20) is obtained with the acceleration from time T to T1 as A1.
A1 = (PNB / J) / √ (2 × (PNB / J) × (T1-T) + V ^ 2) (20)

From this equation (20), it can be seen that the velocity function of equation (19) satisfies the relationship of equation (16). For this reason, the travel distance (deceleration required distance LDCC2) required to decelerate from the speed V equal to or higher than the base rotation speed NB to the speed 0 is obtained by integrating the equation (19) with the deceleration time from the speed V to the base rotation speed NB It is calculated as the sum of the distance and the distance required to decelerate from the base rotational speed NB calculated from the formula (9) to the speed 0. Specifically, the deceleration required distance LDCC2 is calculated using the following equation (21).
LDCC2 = (2 × V ^ 3 + NB ^ 3) / (6 × AMAX × NB) (21)

  Thereafter, the processes of steps ST30 to ST60 of the first embodiment are performed. In the present embodiment, the required deceleration speed LDCC in the first embodiment is replaced with the required deceleration distance LDCC2 calculated in the second embodiment, and the same processing (step ST30 to step ST60) as in the first embodiment is performed. Done.

As in the first embodiment, the relationship between the value of the maximum acceleration AMAX and the value of LDCC2 is also inversely proportional to the equation (21). Therefore, if the deceleration AREF2 at the fixed position stop position control can be expressed by the following expression (22) from the required deceleration distance LDCC2 required for deceleration and the distance to the deceleration stop position (position deviation DRP "). By simply changing the magnitude of acceleration, the distance required for deceleration can be made to coincide with a desired value.
AREF2 = (LDCC2 / DRP ″) AMAX (22)

  As described above, the reference control input calculation unit 12 of the present embodiment rotates the motor 3 at a rotational speed lower than the base rotational speed NB (base rotational speed) set in advance according to the acceleration characteristics of the motor 3. In this case, the deceleration required distance LDCC is calculated based on the maximum acceleration AMAX and the position detection value B. On the other hand, when the motor 3 is rotated at a rotational speed higher than the base rotational speed NB, the maximum acceleration AMAX below the base rotational speed NB is calculated based on the maximum acceleration AMAX, the position detection value B, and the base rotational speed NB. calculate.

  As described above, according to the second embodiment, the deceleration required distance can be calculated even when the maximum acceleration AMAX that can be output by the motor 3 decreases as the speed increases. For this reason, it is possible to easily generate a deceleration pattern in which the position deviation DPR, which is the difference between the position command X and the position detection value B, becomes 0 at the same time as the deceleration stop. Therefore, even in the case of deceleration from the constant output region, it is possible to easily generate a deceleration pattern using the maximum acceleration.

  As described above, the motor drive control device according to the present invention is suitable for drive control of a motor that drives a machine tool.

DESCRIPTION OF SYMBOLS 1 Motor drive control apparatus 2 Position command generation apparatus 3 Motor 4 Position detector 11 Position deviation shaping part 12 Reference control input calculation part 13 Control input calculation part 14 Control input restriction part

Claims (2)

In a motor drive control device that drives and controls a motor based on a position command,
A control input calculation unit that calculates a control input to the motor based on a position deviation that is a difference between the position command and a position detection value detected from the motor, and sends the calculated control input to the motor side,
A control input limiting unit that limits the control input calculated by the control input calculation unit to a predetermined control input limit value or less;
The maximum acceleration that can be output by the motor is calculated based on the position detection value and the control input after the limit, and the minimum acceleration until the vehicle stops decelerating at the maximum acceleration based on the maximum acceleration and the position detection value. A reference control input calculation unit that calculates a deceleration required distance that is a limited necessary distance and calculates a reference control input that is a desired value of the control input based on a ratio between the deceleration required distance and the position deviation;
A position deviation shaping unit that corrects the position deviation so that the control input matches the reference control input;
With
The control input calculation unit calculates the control input based on the corrected position deviation ,
The control input restriction unit outputs the control input after the restriction to the motor and the reference control input calculation unit . The reference control input calculator is
When the motor is rotated at a rotation speed lower than a preset base rotation speed according to the acceleration characteristics of the motor, the deceleration required distance is calculated based on the maximum acceleration and the position detection value. ,
When rotating the motor at a higher rotational speed than the base rotational speed, a maximum acceleration below the base rotational speed is calculated based on the maximum acceleration, the position detection value, and the base rotational speed. The motor drive control device according to claim 1 .

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