JP2003191305A - Drive control device for electrically-driven injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure sufficient responsibility and stability of control operation by making the absolute control value at a plurality of servo motors smaller, even if the synchronization deviates remarkably. <P>SOLUTION: There is provided a synchronization circuit 9 which comprises: a deviation detection part 5 obtaining a deviation value E by subtracting a second detection value Dy at a driving position by the other servo motor 3y from a first detection value Dx at a driving position by the one servo motor 3x; a compensation part 6 compensating the deviation value E; a subtraction part 7 subtracting a correction value for synchronization Se outputted from the compensation part 6 from a control value (Sx) at a first control system Cx; and an addition part 8 adding the correction value for synchronization Se to a control value (Sy) at a second control system Cy. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for an electric injection molding machine suitable for driving a common movable part by a drive part including a pair of servomotors.

[0002]

2. Description of the Related Art Conventionally, an electric injection molding machine is known in which a common movable part is driven by a driving part including a plurality of servomotors.

By the way, in this type of electric injection molding machine, a combination of a plurality of servo motors is used when the target driving force cannot be secured by a single servo motor or when a single servo motor becomes expensive. The purpose is to increase the driving force of the entire drive section or to reduce the cost, but on the other hand, since multiple servo motors are used, how to establish synchronization between each servo motor Is an important issue.

Conventionally, as a means for synchronizing a plurality of servo motors, a synchronizing device disclosed in Japanese Patent Laid-Open No. 2000-117790 is known. This device mechanically establishes synchronization by bridging a timing belt between a plurality of pulleys that are respectively rotated by a plurality of servo motors. On the other hand, in such a mechanical means, there is a limit in responsiveness and accuracy, so a drive control device for establishing synchronization by a plurality of servomotors by an electric means is also known from Japanese Patent No. 2681795. . This device maintains the rotation speed of one of the plurality of electric motors at a set rotation speed, and synchronizes with the rotation speed of the one electric motor so that the rotation speed of the other electric motor becomes equal to the rotation speed of the one electric motor. It is controlled to be equal.

However, in the conventional drive control device which establishes synchronization by such an electric means, the rotation speed of one electric motor (servo motor) is made to follow the rotation speed of the other electric motor to achieve synchronization. As a result, the absolute control amount of the other electric motor becomes larger than that of the one electric motor, and in particular, when the synchronization is largely deviated, there is a drawback in that the responsiveness and stability of the control operation are greatly impaired.

The present invention solves the problems existing in the prior art as described above, and reduces the absolute control amount in a plurality of servomotors, and even if the synchronization is largely deviated, the control operation is suppressed. An object of the present invention is to provide a drive control device for an electric injection molding machine, which can ensure sufficient responsiveness and stability.

[0007]

Means for Solving the Problems and Embodiments The present invention relates to a pair of servomotors 3x, 3y for driving a movable portion 2.
Including a drive unit 3, a first control system Cx that performs feedback control so that the detection value (first detection value) Dx of the drive position by one servo motor 3x becomes the target value Do, and the drive by the other servo motor 3y A drive control device 1 for an electric injection molding machine M including a second control system Cy that performs feedback control so that a detected value (second detected value) Dy of a position becomes a target value Do, and a synchronization unit 4 that synchronizes each drive position. When configuring the above, the deviation detection unit 5 that obtains the deviation value E by subtracting the second detection value Dy from the first detection value Dx, the compensation unit 6 that compensates for the deviation value E, and the synchronization output from this compensation unit 6 It has a subtraction unit 7 that subtracts the correction value Se for control from the control value (Sx) in the first control system Cx, and an addition unit 8 that adds the correction value Se for synchronization to the control value (Sy) in the second control system Cy. It must have a synchronization circuit 9. The features.

Thus, the drive control device 1 according to the present invention
Then, the deviation detection unit 5 obtains a deviation value E obtained by subtracting the second detection value Dy from the first detection value Dx, and further, the deviation value E is compensated by the compensating unit 6 to obtain the synchronization correction value. Se is obtained. On the other hand, the synchronization correction value Se is
It is given to the first control system Cx and the second control system Cy at the same time.
Then, the subtraction unit 7 controls the control value of the first control system Cx (S
The correction value Se for synchronization is subtracted from x), and the correction value Se for synchronization is added to the control value (Sy) of the second control system Cy by the addition unit 8. As a result, for example, even if the synchronization largely deviates from the first detection value Dx in the direction in which the second detection value Dy decreases, the control value (Sx) of the first control system Cx decreases due to the synchronization correction value Se. Is corrected to
Moreover, since the control value (Sy) of the second control system Cy is corrected in the increasing direction, one servo motor 3y (or 3
The problem that the absolute control amount of x) becomes large is solved, and sufficient responsiveness and stability of the control operation are secured.

In this case, according to the preferred embodiment, the subtracting section 7 causes the deviation value Dxe between the first detection value Dx and the target value Do.
The correction value Se for synchronization can be subtracted from the output value Sx of the compensating section 11x for compensating for the above, and the adder section 8 of the compensating section 11y for compensating for the deviation value Dxe between the second detection value Dy and the target value Do. The synchronization correction value Se can be added to the output value Sy. The screw 2s can be applied to the movable portion 2.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, a schematic configuration of an electric injection molding machine M including the drive control device 1 according to this embodiment will be described with reference to FIGS. 2 and 3.

The electric injection molding machine M is equipped with an injection device Mi and a mold clamping device Mc arranged on the upper surface of the machine base 51. Injection device M
i is supported by the injection device moving base 52, and the injection device moving base 52 is selectively displaced to the forward movement position (nozzle touch position) or the backward movement position (nozzle touch release position) by an unillustrated advancing / retreating drive unit. In addition, the injection device moving table 52
At the end of the mold clamping device Mc side above, the heating cylinder support board 5
3 is erected, a drive part support board 54 is erected at the opposite end, and a plurality of tie bars 55 are installed between the heating cylinder support board 53 and the drive part support board 54. . The movable plate 56 is slidably supported by the tie bars 55.

On the other hand, the rear end of the heating cylinder 57 is attached to the front surface of the heating cylinder support board 53. The heating cylinder 57 has an injection nozzle 58 at the front end and a hopper 59 at the rear part. Further, the screw 2s (movable part 2) is inserted inside the heating cylinder 57, and the rear end of the screw 2s is attached to the movable plate 56.
It is rotatably coupled to the rotation support portion 60 provided on the. A servomotor 61 for measurement is attached to the movable plate 56, and a drive pulley 62 attached to the rotary shaft of the servomotor 61 and a driven pulley 63 attached to the rear end of the screw 2s.
An endless belt 64 is bridged between them to form a driving unit 65 for weighing.

On the other hand, a pair of left and right injection servomotors 3x and 3y forming a drive unit 3 for moving the screw 2s forward and backward are attached to the rear surface of the drive unit support board 54. Then, the rotary shafts 66x and 66y of the servo motors 3x and 3y, respectively.
The movable platen 56 and the movable plate 56 are connected by a ball screw mechanism 67x, 67y. Specifically, a pair of left and right nut portions 68x and 68y are fixed to the rear surface of the movable plate 56, and balls that are screwed to the rotation shafts 66x and 66y of the servo motors 3x and 3y and to the nut portions 68x and 68y. Screw 69x, 69
Join the rear ends of y. The rotary shafts 66x and 66y
Are bearings 70x, 7 attached to the drive unit support board 54.
The nuts 68x, 68 are supported by 0y.
At the position of the movable plate 56 corresponding to y, the ball screw 69
Insertion holes 71x, 71y through which x, 69y can be inserted are formed. In addition, in FIG. 3, 72 is a fixed plate of the mold clamping device Mc, and 73 is a fixed mold attached to the fixed plate 72.

Next, the configuration of the drive control device 1 according to this embodiment will be specifically described with reference to FIGS. 1 and 2.

As shown in FIG. 2, the drive control device 1 includes a pair of servo amplifiers 21x and 21y connected to the servo motors 3x and 3y, respectively. Therefore, the servo motors 3x and 3y form a part of the drive control device 1.
The output side of each servo amplifier 21x, 21y is connected to each servo motor 3x, 3y, respectively, and is attached to each servo motor 3x, 3y to detect the rotation speed (rotation speed) of each servo motor 3x, 3y. 22
x and 22y are connected to the servo amplifiers 21x and 21y, respectively. The input side of each servo amplifier 21x, 21y is connected to the output side of the synchronizing circuit 9, and the input side of this synchronizing circuit 9 is connected to the controller 23. In this case, the servo motor 3x, the servo amplifier 21x, the rotary encoder 22x, and a part of the synchronization circuit 9 constitute the first control system Cx, and one of the servo motor 3y, the servo amplifier 21y, the rotary encoder 22y, and the synchronization circuit 9 is formed. The unit constitutes the second control system Cy.

FIG. 1 shows a synchronizing circuit 9 and a servo amplifier 21.
A specific configuration of x and 21y is shown. The controller 2
From 3, at least the target value Do of the position is given to the synchronizing circuit 9, and the velocity command offset values Fx and Fy for obtaining the velocity command value are given.

On the other hand, the synchronizing circuit 9 includes a first control system Cx and a second control system Cy. The first control system Cx outputs from the position deviation detection unit 31x that detects a deviation between the detection value (first detection value Dx) of the drive position obtained from the rotary encoder 22x and the target value Do, and the position deviation detection unit 31x. A position compensation unit 11x that compensates the deviation value Dxe with a proportional constant (P constant), and an output value Sxi of the position compensation unit 11x.
Further, an offset value adding unit 32x for adding the speed command offset value Fx and a subtracting unit 7 for subtracting a synchronization correction value Se described later from the output value Sx (control value) of the offset value adding unit 32x are provided.

Similarly, the second control system Cy has a drive position detection value (second detection value D) obtained from the rotary encoder 22y.
y) and the target deviation Do between the position deviation detector 3 for detecting the deviation
1y, a position compensation unit 11y that compensates the deviation value Dye output from the position deviation detection unit 31y with a proportional constant (P constant), and an offset that adds a speed command offset value Fy to the output value Syi of the position compensation unit 11y. Value adder 3
2y and the output value Sy of the offset value adding unit 32y
The (control value) is provided with an adder 8 for adding a synchronization correction value Se described later.

Further, the synchronizing circuit 9 has a first detection value Dx.
A deviation detection unit 5 that obtains a deviation value E by subtracting the second detection value Dy from the compensation unit 6 and a compensation unit 6 that compensates the deviation value E with a proportional integral constant (PI constant). Then, the synchronization correction value Se output from the compensator 6 is given to the subtractor 7 in the first control system Cx and the adder 8 in the second control system Cy.

On the other hand, the servo amplifier 21x provided in the first control system Cx receives, from the input side, the speed deviation detection unit 33x to which the output value Vxo of the subtraction unit 7 is added and the first detection value Dx obtained from the rotary encoder 22x. Differentiate according to the time to obtain the detected value Vxd of the speed, and the detected value Vxd is applied to the speed deviation detection unit 33x and the speed conversion unit 34x and the speed deviation value Vxe output from the speed deviation detection unit 33x are proportional to the integral constant (PI). A deviation value output from the current deviation detection unit 36x and the current deviation detection unit 36x, which is provided with a speed feedback control system having a speed compensation unit 35x for compensation by a constant) Is provided with a current feedback control system having a current compensating unit 37x for compensating the current with a proportional integral constant (PI constant). Output of 7x servomotor 3x
Connect to.

Further, the servo amplifier 21y provided in the second control system Cy receives, from the input side, the speed deviation detection unit 33y to which the output value Vyo of the addition unit 8 is added and the second detection value Dy obtained from the rotary encoder 22y. Differentiate according to time to obtain the detected value Vyd of the speed, and apply the detected value Vyd to the speed deviation detection unit 33y to the speed conversion unit 34y and the speed deviation value Vye output from the speed deviation detection unit 33y. A deviation value output from the current deviation detection unit 36y and the current deviation detection unit 36y, which is provided with a speed feedback control system having a speed compensation unit 35y for compensation by a constant) Is provided with a current feedback control system having a current compensator 37y for compensating with a proportional integral constant (PI constant). Output of 7y servomotor 3y
Connect to.

Next, the operation of the drive control device 1 according to this embodiment, particularly the operation in the injection process, will be described with reference to the drawings.

In the injection process, the screw 2s moves forward according to a preset speed command value. The basic operation of the first control system Cx in this case is as follows. First, the speed command offset value Fx is given from the controller 23, and the position command value Do is calculated as the position deviation detection unit 31x.
Granted to. On the other hand, the first detection value Dx obtained from the rotary encoder 22x is given to the position deviation detection unit 31x, and the deviation value Dxe between the first detection value Dx and the target value Do is obtained from the position deviation detection unit 31x. Then, the deviation value Dxe is compensated by the proportional constant (P constant) in the position compensating unit 11x. As a result, the compensated output value Sxi is obtained, so basically, this output value Sxi is obtained.
The feedback control of the position in the first control system Cx is performed based on the magnitude of.

The output value Sxi is given to the offset value adding unit 32x, and the offset value adding unit 32x is provided.
Then, the speed command offset value Fx is added to the output value Sxi. As a result, the output value Sx is obtained from the offset value adding unit 32x. This output value Sx is obtained by ignoring the subtracting unit 7 when the speed deviation detecting unit 3 of the servo amplifier 21x is used.
It becomes the command value of the speed given to 3x. On the other hand, the first detection value Dx is given to the speed conversion unit 34x, converted into the speed detection value Vxd by the speed conversion unit 34x, and the speed detection value Vxd is given to the speed deviation detection unit 33x. From the speed deviation detection unit 33x, a speed deviation value Vxe between the speed command value and the detected value Vxd is obtained. The speed deviation value Vxe is compensated by the proportional-plus-integral constant (PI constant) in the speed compensator 35x, and the compensated output value Kx is obtained from the speed compensator 35x.
Therefore, basically, the speed feedback control in the first control system Cx is performed based on the magnitude of the output value Kx. Further, the output value Kx is determined by the current deviation detection unit 36.
x and a current compensating unit 37x, the current is output via a feedback control system (minor loop), and basic servo control is performed on the servo motor 3x.

On the other hand, the basic operation of the second control system Cy is performed in the same manner as the first control system Cx. First, the controller 23 gives a speed command offset value Fy (usually Fy = Fx) and a position command value Do to the position deviation detector 31y. On the other hand, the rotary encoder 22y
The second detection value Dy obtained from the position deviation detection unit 31y is given to the position deviation detection unit 31y.
The deviation value Dye between the target value Do and the target value Do is obtained. The deviation value Dye is the proportional constant (P
Constant). As a result, the compensated output value Syi is obtained, and therefore the position feedback control is performed in the second control system Cy based on the magnitude of this output value Syi.

Further, the output value Syi is given to the offset value adding section 32y, and this offset value adding section 32y is provided.
Then, the speed command offset value Fy is added to the output value Syi. As a result, the output value Sy is obtained from the offset value adding unit 32y. This output value Sy is obtained by ignoring the addition unit 8 and detecting the speed deviation detection unit 3 of the servo amplifier 21y.
It becomes the command value of the speed given to 3y. On the other hand, the second detection value Dy is given to the speed conversion unit 34y, converted into the speed detection value Vyd by the speed conversion unit 34y, and the speed detection value Vyd is given to the speed deviation detection unit 33y. From the speed deviation detection unit 33y, the speed deviation value Vye between the speed command value and the detection value Vyd is obtained. The speed deviation value Vye is compensated by the proportional-plus-integral constant (PI constant) in the speed compensator 35y, and the compensated output value Ky is obtained from the speed compensator 35y.
Therefore, basically, the speed feedback control in the second control system Cy is performed based on the magnitude of the output value Ky. Furthermore, the output value Ky is determined by the current deviation detection unit 36.
y and a current feedback control system (minor loop) having a current compensating unit 37y are used for output, and basic servo control for the servo motor 3y is performed.

As described above, the first control system Cx and the second control system Cy are independent of each other, and feedback control is performed on the position, speed, and current, and the position command value Do is obtained.
And speed command values (position command offset values Fx, Fy)
The control is performed so as to match with.

On the other hand, the synchronization circuit 9 establishes the synchronization so that the driving positions of the servo motors 3x and 3y coincide with each other. First, in the non-inverting input section of the deviation detecting section 5,
The first detection value Dx obtained from the rotary encoder 22x is given, and the second detection value Dy obtained from the rotary encoder 22y is given to the inverting input section of the deviation detection unit 5. As a result, the deviation value E obtained by subtracting the second detection value Dy from the first detection value Dx is obtained from the output unit of the deviation detection unit 5. Further, this deviation value E is given to the compensation unit 6,
It is compensated by the proportional-plus-integral constant (PI constant) in the compensator 6.

Therefore, since the compensated synchronization correction value Se is obtained from the compensator 6, the synchronization correction value Se is
It is simultaneously given to the subtracting unit 7 of the first control system Cx and the adding unit 8 of the second control system Cy. As a result, in the subtracting unit 7, the output value Sx (control value) of the offset value adding unit 32x
The correction value Se for synchronization is subtracted from the addition unit 8
Then, the synchronization correction value Se is added to the output value Sy (control value) of the offset value addition unit 32y. Therefore, for example, even if the synchronization largely deviates from the first detection value Dx in the direction in which the second detection value Dy decreases, the synchronization correction value Se reduces the control value (Sx) of the first control system Cx. Direction, and the control value (Sy) of the second control system Cy is increased, the problem that the absolute control amount of one servo motor 3y (or 3x) becomes large is solved, Sufficient responsiveness and stability of control operation are ensured.

The embodiment has been described in detail above.
The present invention is not limited to such an embodiment,
The detailed configuration, shape, quantity, etc. can be arbitrarily changed, added, or deleted without departing from the scope of the present invention.

For example, in the embodiment, a pair of servo motors 3
Although the case where x, 3y is used is shown, the same operation can be performed when three or more servo motors 3x are used. In this case, for example, if three servo motors 3x, 3y, 3z are used, a pair of servo motors 3x, 3y, a pair of servo motors 3y, 3z, and a pair of servo motors 3x,
The same operation can be performed using a plurality of sets of 3z. In addition, the movable part 2
Although the screw 2s is illustrated as above, it can be similarly applied to other movable parts such as a movable plate on the mold clamping device Mc side.

[0033]

As described above, the drive control device for an electric injection molding machine according to the present invention includes a drive section including a pair of servo motors for driving a movable section, and a first detection value of a drive position by one servo motor. Synchronizes each drive position with a first control system that performs feedback control so that the target value becomes the target value, and a second control system that performs feedback control so that the second detected value of the drive position by the other servo motor becomes the target value. An apparatus including a synchronization unit, wherein a deviation detection unit that obtains a deviation value by subtracting a second detection value from a first detection value, a compensation unit that compensates this deviation value, and a synchronization correction output from this compensation unit An absolute control amount in a plurality of servo motors is provided because a synchronization circuit having a subtraction unit that subtracts the value from the control value in the first control system and an addition unit that adds the synchronization correction value to the control value in the second control system is provided. To Can fence, even if the even synchronization is lost greatly, it is possible to ensure a sufficient response and stability of the control operation. Therefore, it is particularly suitable for use in an injection servomotor that requires high responsiveness and high stability.

[Brief description of drawings]

FIG. 1 is a specific configuration diagram of a drive control device according to a preferred embodiment of the present invention,

FIG. 2 is a plan configuration diagram showing a part of an electric injection molding machine including the drive control device.

FIG. 3 is a side view showing a part of an electric injection molding machine including the drive control device.

[Explanation of symbols]

1 Drive control device 2 movable parts 2s screw 3 drive 3x servo motor 3y servo motor 4 synchronization section 5 Deviation detection section 6 Compensation Department 7 Subtraction unit 8 adder 9 Synchronous circuit 11x compensation section 11y Compensation Department Cx first control system Cy Second control system Dx first detection value Dy second detection value Do target value Dxe deviation value Dye deviation value Correction value for Se synchronization Sx output value Sy output value M electric injection molding machine E deviation value

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshito Ariga             2110 Nanjo, Nanjo, Sakagi-cho, Hanashina-gun, Nagano             Within Seisei Kogyo Co., Ltd. (72) Inventor Mitsuhiro Ogasawara             2110 Nanjo, Nanjo, Sakagi-cho, Hanashina-gun, Nagano             Within Seisei Kogyo Co., Ltd. F-term (reference) 4F206 AP06 AR07 JA07 JD01 JL02                       JP13 JP30 JT33 JT35 JT40

Claims (4)

[Claims] 1. A drive unit including a pair of servo motors that drive a movable unit, and a first control system that performs feedback control so that a detection value (first detection value) of a drive position by one servo motor becomes a target value. And a second control system that performs feedback control so that the detection value (second detection value) of the drive position by the other servo motor becomes the target value, and an electric injection molding machine including a synchronization unit that synchronizes each drive position. In the drive control device, a deviation detection unit that subtracts the second detection value from the first detection value to obtain a deviation value, a compensation unit that compensates the deviation value, and a synchronization correction value that is output from the compensation unit. An electric injection molding machine comprising: a synchronous circuit having a subtracting unit for subtracting from the control value in the first control system, and an adding unit for adding the synchronization correction value to the control value in the second control system. Drive Dynamic control device. 2. The subtraction unit subtracts the synchronization correction value from an output value of a compensation unit that compensates a deviation value between the first detection value and the target value. Drive controller for electric injection molding machine. 3. The addition unit adds the synchronization correction value to an output value of a compensation unit that compensates for a deviation value between the second detection value and the target value. Drive controller for electric injection molding machine. 4. The drive control device for an electric injection molding machine according to claim 1, wherein the movable portion is a screw.