JPH072368B2 - Motor control device for extrusion molding line - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a motor control device for an extrusion molding line, and more particularly to a motor control device for an extrusion molding line that includes an extruder and is used for plastic molding of long products and laminates. Number of rotations (speed)
The present invention relates to improvement of a motor control device suitable for control.

[Conventional technology]

Extrusion molding line for extruding a laminate such as a long product such as a plastic pipe or a plastic sheet is configured by connecting a take-up machine to an extruder, for example, and extruding a molten plastic raw material in the extruder, The take-out machine takes the extruded product.

In such an extrusion molding line, in order to maintain the quality of the molded product at the time of starting and ending the production of the product and to avoid the mechanical failure of the extruder, the take-off machine, etc., operate the extruder and the take-up machine. The motor to be driven is required to be driven within a predetermined rated range, particularly within a rotation speed (speed) change rate limit.

[Problems to be Solved by the Invention]

However, even if a motor equipped with a rate-of-change limiter is used to drive within the prescribed rate-of-change limit, the motors should be selected in consideration of the entire mechanical system of the extrusion-molding line to operate the extrusion-molding line. It is difficult.

Therefore, in an extrusion molding line in which the number of motors to be controlled is large, there is much room for improvement in the control device for controlling the motors.

When using a motor that does not have a rate of change limiter,
When the rotation speed command signal for rotating the motor suddenly changes for some reason, the mechanical system may be damaged.

The present invention has been made under such circumstances, and provides a motor control device capable of driving a plurality of motors in an extrusion molding line within a range not exceeding an arbitrarily set rotational speed change rate limit. To aim.

[Means for Solving the Problems]

In order to solve such a problem, the present invention provides a plurality of motors 100 arranged in an extrusion molding line including an extruder and a plurality of these motors as shown in the claim correspondence diagram of FIG. Rotation speed command means 1 for commanding the rotation speed to 100
01, a change rate limit storage means 102 for storing beforehand a change rate limit value of the number of rotations of the motor 100, and a control means 103 for controlling the rotation number command means 101.

Then, the control means 103 calculates the rotation speed change rate of each of the motors 100 from the amount of change in the rotation speed output to the rotation speed command means 101, and changes the change rate limit of each motor from the change rate limit storage means 102. When the rotational speed change rate exceeds the change rate limit value, the rotational speed command means 101 is controlled so that the rotational speed change rate of each motor 100 is suppressed to the change rate limit value.

Further, according to the present invention, the change rate limit storage means 102 stores a first change rate limit value as an initial setting value and a first change rate limit value.
Is configured to store a second change rate limit value as a reset value within the range of the change rate limit value constraint, and the control means 103 to preferentially compare the second change rate limit value. Should be configured.

Further, according to the present invention, the rotation speed command means 101 uses the plurality of motors 100 as main motors and slave motors subordinate to the motors and commands them to rotate at a predetermined ratio, and the control means 103 controls the slave motors. When the rotational speed change rate exceeds the change rate limit value, the rotational speeds of the main and slave motors can be suppressed to the change rate limit value.

[Action]

In the present invention including such means, the rotation speed command means 101 outputs a rotation speed command signal to the motor 100 under the control of the control means 103, and the motor 100 is rotationally driven.

At that time, the control means 103 calculates the rotation speed change rate of each motor from the change amount of the rotation speed output to the rotation speed command means 101, and changes rate limit value of each motor from the change rate limit storage means 102. When the rotation speed change rate exceeds the change rate limit value, the rotation speed command means 101 is controlled so that the rotation speed change rate of each motor 100 is suppressed to the change rate limit value. A rotation command signal that does not exceed the limit is output to the motor 100.

The change rate limit storage means 102 stores the first and second change rate limit values, and the control means
In the configuration in which 103 preferentially compares the second change rate limit value, the change amount of the rotational speed and the reset change rate limit are compared, and at various stages, for example, at the time of manufacturing or operating the device. The rate of change limit value can be set arbitrarily.

Further, in the configuration in which the rotation speed command means 101 causes the main and slave motors to operate in ratio, and the control means 103 controls the rotation speeds of the main and slave motors according to the rotation speed change rate of the slave motor, in the ratio operation, Change rate limit control is performed based on the number of rotations of the motor.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic diagram showing an example of an extrusion molding line in which the motor control device according to the present invention is implemented.

In the figure, an extruder 1 includes a main screw 5 inside a molding machine table 3, an extrusion motor 7 for rotationally driving the main screw 5, and a rotation speed detection sensor 9 such as a tachogenerator for detecting the rotation speed of the extrusion motor 7. , And has a conventionally known configuration having other configurations.

A hopper that supplies plastic raw materials to the molding machine table 3.
A raw material feeder device 15 having an 11 and an auxiliary screw 13 and the like is provided, and the raw material feeder device 15 includes a feeder motor 17 that rotationally drives the auxiliary screw 13 and a sensor 19 that detects the number of rotations of the feeder motor 17. It is arranged. Reference numerals 21 and 23 are a temperature sensor and a pressure sensor arranged on the molding machine base 3.

In this extruder 1, a plastic raw material supplied from a raw material feeder device 15 to a main screw 5 portion by a feeder motor 17 is driven by a rotation drive of the main screw 5 to form a molded product 25 from a die (not shown) arranged near this tip. Is to be extruded as.

The extruded molded product 25 is adapted to be taken by, for example, two sets of take-off machines 27 and 29, and rollers 27a and 29a for taking the molded product 25 in the take-off machines 27 and 29 respectively take motors 31 and 33. The rotation speed of the take-up motors 31, 33 is the same as that of the sensors 9, 19
It is detected by 5, 37.

The extrusion motor 7, the feeder motor 17, the take-up motors 31, 33 and the sensors 9, 19, 35, 37 are connected to the motor control device A of the present invention by a cable. , 17, 31, 33 rpm (speed)
Is to control.

FIG. 3 is a block diagram showing the configuration of a motor control device A for an extrusion molding line according to the present invention.

In the figure, a control circuit 39 as a control means is a CPU 41 that is a main element that achieves the functions described later, a ROM 43 that stores an operation program of the CPU 41, a RAM 45 that temporarily stores data in the calculation process of the CPU 41, and It has a data input / output interface (I / O) 47, etc., and is a main part of a so-called microcomputer.

The master-slave relationship setting device 49, the mode switching device 51, the rotation speed setting device 53, and the change rate limit setting device 55 connected to the control circuit 39 are, as shown in FIG. 2, a keyboard formed on the operation surface of the device main body. It is formed of 57, and the details will be described later.

The master-slave relationship storage circuit 59, the rotation speed storage circuit 61, and the rate-of-change limit storage circuit 63 connected to the control circuit 39 are external storage circuits 65 as storage means composed of RAM and are used by dividing the storage area. There is.

The display device 66 connected to the control circuit 39 is, for example, a plasma display device that displays a setting screen of various data for the motor control device A and an operation monitor screen.

The rotation speed measuring device 67 includes a rotation speed detecting sensor 9 shown in FIG.
A / D that outputs an analog electric signal corresponding to the number of revolutions of the motors 7, 17, 31, 33 including 19, 35, 37, and converts the analog signal into a digital signal and outputs the measured number of revolutions signal.
It is connected to the control circuit 39 via the conversion circuit 69.

The D / A conversion circuit 71 converts the digital rotation speed signal from the control circuit 39 into an analog signal and is connected to the speed command signal output circuit 73 to form speed command means. 73 is each motor 7, 17, 31, in FIG.
It outputs a rotation speed command signal to 33.

The rate-of-change limit setting device 55 is under the control of the control circuit 39.
Change time until reaching the maximum range (maximum number of rotations) for each motor 7, 17, 31, 33, roughly each motor 7,
It is a means to input the change rate limit value of the rotation speed of 17, 31, 33, and each change rate limit value is a change rate limit storage circuit.
It will be remembered in 63.

This change rate limit storage circuit 63 has a first
The initial setting value as the change rate limit value and the reset value as the second change rate limit value can be stored.

To set the change rate limit value for each motor, for example,
This is performed using the motor system setting screen shown in FIG.

That is, the change rate limit value input from the change rate limit setting device 55 for all of the plurality of motors CH1 to CH12,
Under the control of the control circuit 39, "rate of change limit [sec / FS]"
Is input and displayed in the corresponding column of, and is initially set in an arbitrary range from 0 to 999 [seconds / FS]. The motor CH1 of 60 is set so that the motor CH1 does not change faster than 60 [sec / FS].

The motors CH1 to CH12 in FIG. 4 are, for example, the motors 7, 17, 31, 33 in FIG. 2, and the following description is also the same.

Further, as shown in FIG. 5 and FIG. 6, it is also possible to reset within the range of the above-mentioned initial setting by using the setting screen of each motor.

FIG. 5 is a screen for setting the automatic operation mode of a plurality of motors, and FIG. 6 is a speed setting screen in the manual mode of each motor. Again, the change rate limit value input from the change rate limit setting device 55 is displayed. Under the control of the control circuit 39,
The change rate limit [seconds / FS] is entered and displayed in the relevant field and reset.

The master-slave relationship setting device 49 changes the master-slave relationship of which of the motors (motors CH1 to CH12 in FIG. 4) in FIG. 2 is the master motor and which is the slave motor for the master motor. To do.

Regarding the master-slave relationship, the master-slave relationship input from the master-slave relationship setting device 49 is input and displayed in the "main motor" column under the control of the control circuit 39 using the motor system setting screen of FIG. It is stored in the storage circuit 59, and one or more slave motors are subordinately set to each main motor with a plurality of motors as main motors, or another slave motor is subordinately set to a slave motor subordinate to the main motor.

In the "Main motor" column in Fig. 4, CH1 to which "0" was input is the main motor, and CH1 to which "1" has been input.
H2 indicates a slave motor subordinate to the main motor CH1, and motor CH3 to which "2" is input indicates a submotor subordinate to the submotor CH2.

The "startup group" column in FIG. 4 shows the group number of the motors to be started together, and when the startup group number "1" is designated, the motors CH1 to CH4 are started together.

In the mode switching device 51, the motor control device A uses the motors 7,
It is set whether to control 17, 31, 33 in the independent operation or ratio operation mode.It is configured so that the manual mode and the automatic mode can be selected under the independent operation and ratio operation modes, respectively. It is displayed like the column of the operation mode in FIG.

The manual mode in the single operation mode is for individually controlling each motor 7, 17, 31, 33 under the control of the control circuit 39 with the rotation speed input from the rotation speed setting device 53, and is the automatic mode in the single operation mode. The mode is to automatically control each of the motors 7, 17, 31, and 33 individually at a rotation speed input in advance from the rotation speed setting device 53.

For example, as indicated by "1CH" in FIG. 5, the automatic operation is controlled to reach the automatic operation set value of 240 [rpm] through three stages of automatic operation.

Under the control of the control circuit 39, the ratio operation mode is a designated rotation speed for the main motor, and for the slave motors, the ratio calculation is performed from the rotation speeds of the master motors to which the slave motors depend, and the respective motors 7, 17, It controls the number of rotations of 31, 33.

The rotation speed setting device 53 is for manually inputting the rotation speed of each motor 7, 17, 31, 33, for example, and is stored in the rotation speed storage circuit 61 under the control of the control circuit 39.

The control circuit 39 controls the rotation speed setting device 53 under the condition that the mode switching device 51 selects the manual mode in the independent operation.
When the number of rotations of each motor 7, 17, 31, 33 is input from
Each rotation speed signal is output as it is to the D / A conversion circuit 71, and the rotation speed storage circuit 61 stores the rotation speed.

When the mode switching device 51 selects the automatic mode in the independent operation, the rotation speed input in advance from the rotation speed setting device 53, for example, the rotation speed stored in the rotation speed storage circuit 61 is read to read each of the motors 7 and 17. , 31, 33 are output to the D / A conversion circuit 71 in a predetermined procedure.

The control circuit 39 refers to the master-slave relationship data stored in the master-slave relationship storage device 59 when the mode switching device 51 selects the ratio operation mode, and measures the rotation speed signal from the A / D conversion circuit 69 or A signal related to the speed command signal closest to the D / A conversion circuit 71 (substantially a digital signal equivalent to the speed command signal)
Calculate the rotation speed ratio of the main and slave motors, calculate the rotation speed of each main motor based on the speed setting for the main motor, and calculate the rotation speed of the slave motor from the rotation speed of the main motor according to the rotation speed ratio. It has a function of outputting to the D / A conversion circuit 71 and storing the rotation speed in the rotation speed storage circuit 61.

The control circuit 39 calculates the change rate of the rotation speed from each rotation speed signal output to the D / A conversion circuit 71 for all the motors instructed to start, and the calculated change rate and change rate limit storage circuit 63. Change rate limit value from, and if there is a rotation speed signal that exceeds the change rate limit value,
It has a function of outputting the change rate limit value as a change rate to the D / A conversion circuit 71 and causing the speed command signal output circuit 73 to output a rotation speed command signal that does not exceed the change rate limit value.

The comparison function with the change rate limit value is similarly performed in both the automatic mode and the manual mode, and the change rate limit value read from the change rate limit storage circuit 63 has priority over the reset value and the reset value exists. If not, the initial setting value is read and compared.

The motor control device A of the present invention configured as described above will be clarified by the description of the control operation with reference to the flowchart shown in FIG.

When the program is started by setting, for example, the ratio operation mode in the mode switching device 51, the control circuit 39 calculates the rotation speed change rate V of the motor n (CHn) in step 200, and the control circuit 39 changes in step 201. The rate-of-change limit value S is fetched from the rate-limit storage circuit 63, and in the next step 202, it is determined whether or not the rotational speed change rate V exceeds the rate-of-change limit value S.

This change rate limit value S is compared with the reset value if there is a reset value in the change rate limit storage circuit 63, and with the initial set value if there is no reset value.

For example, the change rate limit value S is 400 and the rotation speed change rate V is 5
If it is 00, the rotational speed change rate V is slower than the change rate limit value S (V ≧ S), so that step 202 becomes YES and the routine proceeds to step 204, where the change rate limit value is 400 and the rotational speed change rate V is In the case of 300, the rotational speed change rate V is faster than the change rate limit value S (V <S), so step 202 becomes NO and the routine proceeds to step 203.

In step 203, the rotational speed change rate A is set to the change rate limit value S
And the value obtained by adding the number of revolutions corresponding to the change amount to the old (previous) number of revolutions in step 204 is set as the new number of revolutions of the motor n. Speed command signal output circuit 73 so that n rotates comparatively
Control and exit.

〔The invention's effect〕

As described above, in the motor control device of the present invention, the rotation speed change rate of each motor is calculated by the control means and compared with the preset change rate limit value, and the rotation speed change rate to those motors is changed. When the value exceeds the change rate, the change rate limit value is used as the change rate of the rotation number to control the rotation number command means, and the rotation number command signal to the motor is controlled so as not to exceed the change rate limit. It becomes easy to drive all of them within a range that does not exceed the change rate limit value, and proper and stable motor control can be performed in consideration of the entire extrusion molding line when the molding line is started up or down.

Therefore, it is difficult to cause an abnormality in the extrusion molding line by avoiding a failure of a mechanical system such as an extruder or a take-up machine.

In particular, the present invention is suitable when a motor having a large number of motor points to be controlled and having no change rate limiter is used.

Then, in the configuration in which the first and second change rate limit values are stored and compared with the second change rate limit value with priority, the change rate is arbitrarily set at various stages, for example, at the time of manufacturing or operating the device. The limit value can be set and various molding can be supported.

Furthermore, in the configuration in which the rotation speeds of the main and slave motors are controlled by the rotation speed change rate of the secondary motor during ratio operation,
The rate of change limit control is performed based on the rotation speed of the motor during the ratio operation, and further safe operation can be achieved.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram corresponding to the claims according to the present invention, FIG. 2 is a schematic diagram showing an example of an extrusion molding line including a motor control device of the present invention, and FIG. 3 is a motor according to the present invention. Block diagram showing an embodiment of the control device, FIG.
FIG. 6 is a diagram showing a screen for setting the change rate limit value in the present invention, and FIG. 7 is a flowchart for explaining the operation of the present invention. 1 …… Extruder 3 …… Molding machine stand 5 …… Screw 7 …… Extrusion motor 9,19,35,37 …… Sensor 13 …… Sub screw 15 …… Raw material feeder device 17 …… Feeder motor 25… … Molded products 27, 29 …… Pulling machine 31, 33 …… Pulling motor 39 …… Control circuit 41 …… CPU 49 …… Master-slave relationship setting device 51 …… Mode switching device 53 …… Rotation speed setting device 55 …… Change rate limit setting device 59 …… Master-slave relationship storage circuit 61 …… Ratio rotation speed storage circuit 63 …… Change rate limit storage circuit 66 …… Display device 67 …… Rotation speed measurement device 69 …… A / D conversion circuit 71… D / A converter circuit 73 Speed command signal output circuit A Motor control device 100 Motor 101 Rotation speed command means 102 Change rate limit storage means 103 Control means

Front page continuation (72) Inventor Toshihisa Miyaki 5-16-6 Kugahara, Ota-ku, Tokyo Rika Kogyo Co., Ltd. (56) Reference JP-A-61-172718 (JP, A)

Claims (3)

[Claims] 1. A plurality of motors arranged in an extrusion molding line including an extruder, a rotation speed command means for commanding a rotation speed to the plurality of motors, and a change rate limit value of the rotation speed of each motor is stored. Change rate limit storage means and control means for controlling the rotation speed command means, wherein the rotation speed change rate of each motor is calculated from the amount of change in the rotation speed output to the rotation speed command means. The change rate limit value of each motor from the rate limit storage means is compared, and when the rotation speed change rate exceeds the change rate limit value, the rotation speed change rate of each motor is suppressed to the change rate limit value. A motor control device for an extrusion molding line, comprising: a control unit that controls the rotation speed command unit. 2. The change rate limit storage means has a first change rate limit value as an initial set value, and a second change rate as a reset value within a constraint range of the first change rate limit value. The motor control device for an extrusion molding line according to claim 1, wherein a limit value is stored, and the control means preferentially compares the second change rate limit value. 3. The rotation speed command means serves as a main motor and a slave motor subordinate to the plurality of motors to command rotation of these at a predetermined ratio, and the control means changes the rotation speed of the slave motor. 3. The motor control device for an extrusion molding line according to claim 1, wherein when the rate exceeds the change rate limit value, the rotation speeds of the main and slave motors are suppressed to the change rate limit value.