JPH032026A - Control device for motor in extrusion molding line - Google Patents

Abstract

PURPOSE:To properly and stable control a motor while considering the whole extrusion molding line by calculating the rate of change in r.p.m or the respective motors by a controlling means and controlling an r.p.m. command means while keeping the limit value of the rate of change as the rate of change in r.p.m. when the rate of change in r.p.m. exceeds the limit value of the rate of change. CONSTITUTION:An r.p.m. command signal is output to a motor 100 from an r.p.m. command means 101 by control of a controlling means 103. The motor 100 is rotated and driven. In this case, this controlling means 103 calculates the rate of change in r.p.m. of the respective motors and compares this calcu lated value with the limit value of the rate of change for the respective motors which is sent from a limit value memory means 102 of the rate of change. When the rate of change in r.p.m. exceeds the limit value of the rate of change, the r.p.m. command means 101 is controlled so that the rate of change in r.p.m. for the respective motors 100 is inhibited to the limit value of the rate of change. A rotation command signal is output to the respective motors 100 from the r.p.m. command means 101 so that the rate of change in r.p.m. does not exceed the limit value of the rate of change.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a motor control device for an extrusion molding line, and in particular to a motor control device for an extrusion molding line that includes an extruder and is used for plastic molding of long objects and laminates. The present invention relates to an improvement of a motor control device suitable for controlling the number of rotations (speed).

[Conventional technology]

An extrusion molding line for extruding and molding long objects such as plastic pipes and laminates such as plastic sheets is configured by connecting a take-up machine to an extruder, for example, and extrudes and molds molten plastic raw materials in the extruder. The structure is such that the extruded molded product is taken up by a taking-off machine.

In such extrusion molding lines, the extruder and take-off machine are operated in order to maintain the quality of the molded product at the start and end of production and to avoid mechanical failures such as the extruder and take-off machine. It is required that the motor to be driven be driven within a predetermined rated range, particularly within a rotation speed (speed) change rate limit.

[Problem to be solved by the invention]

However, even if a motor is equipped with a rate-of-change limiter to drive within a predetermined rate-of-change limit, the extrusion line cannot be operated by selecting these motors in consideration of the entire mechanical system of the extrusion line. It is difficult. Therefore, in an extrusion molding line where a large number of motors are controlled, there is much room for improvement in the control device that controls the motors.

Also, when using a motor that does not have a rate of change limiter,
When the rotational speed command signal for rotating the motor suddenly changes for some reason, there is a risk that the two mechanical systems will break down.

The present invention was made under these circumstances.

It is an object of the present invention to provide a motor control device capable of driving a plurality of motors in an extrusion molding line within a range that does not exceed an arbitrarily set rotation speed change rate limit.

Means for Solving Problem C] In order to solve such problems, the present invention, as shown in the diagram corresponding to the claims in FIG. O, a rotation speed command means 101 that commands the rotation speed to these plurality of motors 100, a change rate limit storage means 102 that stores in advance a rotation speed limit value of the rotation speed of these motors 1°O, and the rotation speed command means. 101 is provided with a control means 103 for controlling the control means 101.

1 control means 103 calculates the rotation speed change rate of each of the motors 100 and stores the change rate limit storage means 102.
The rotation speed change rate of each motor 100 is compared with the change rate limit value of each motor, and when the rotation speed change rate exceeds the change rate limit value, the rotation speed is set so that the rotation speed change rate of each motor 100 is suppressed to the change rate limit value. It controls the command means 101.

Further, in the present invention, the rate-of-change limit storage means 102 can be configured to store a first rate-of-change limit value and a second rate-of-change limit value within the constraints of the first rate-of-change limit value. It is.

Furthermore, one aspect of the present invention is that the rotation speed command means 101 commands the plurality of motors 100 to rotate at a predetermined ratio as a main motor and a slave motor subordinate thereto,
The control means 103 can be configured to suppress the rotational speeds of the main and slave motors to the rate-of-change limit value when the rotational speed change rate of the secondary motor exceeds the rate-of-change limit value.

C Effect] In the present invention equipped with such means, a rotation speed command signal is output from the rotation speed command means 101 to the motor 100 under the control of the control means 103, and the motor 100 is rotationally driven.

At this time, the control means 103 calculates the rotation speed change rate of each motor and compares it with the change 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 to suppress the rotation speed change rate of each motor 100 to the change rate limit value.

A rotation command signal that does not exceed the rate of change limit 7 is output from the rotation speed command means 101 to the motor 100.

When the rate-of-change limit storage means 102 stores a plurality of rate-of-change limit values, the rate-of-change limit value can be arbitrarily set at various stages, such as during manufacturing or operation of the device.

Furthermore, in a configuration in which the rotation speed command means 101 causes the main and slave motors to operate at a 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, The rate of change is limited and controlled based on the motor rotation speed.

〔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 on which the motor control device according to the present invention is implemented.

In the figure, the extruder 1 has a main screw in the molding machine table 3.
5, an extrusion motor 7 that rotates the extrusion motor 7, and a rotation speed detection sensor 9 such as a tacho generator that detects the rotation speed of the extrusion motor 7. It has a conventionally known configuration having other configurations.

The molding machine table 3 is equipped with a raw material feeder device 15 having a hopper 11 for supplying plastic raw materials, a sub-screw 13, and the like, and the raw material feeder device 15 includes a feeder motor 1 that rotationally drives the sub-screw 13.
7 and a sensor 19 for detecting the rotation speed of this feeder motor 17 are arranged. Reference numerals 21 and 23 are temperature sensors and pressure sensors arranged on the molding machine stand 3.

This extruder 1 uses a die (not shown) disposed near the tip of the plastic raw material fed to the main screw 5 by the feeder motor 17 from the raw material feeder 15 by rotationally driving the main screw 5 to form the plastic raw material. It is extruded as a product 25.

The extruded molded product 25 is transferred to 9, for example, two sets of take-off machines 27.2.
9, each collection machine 2
-7.29 Roller 27a that takes up the molded product 25
, 29a are each rotated by a take-up motor 31.33, and the rotation speed of the take-up motor 31.33 is detected by a sensor 35.37 similar to the sensors 9 and 19.

The extrusion motor 7, the feeder motor 17, the take-up motors 31, 33, and the sensors 9, 1935.37 are connected to the motor control device A of the present invention by a cable, and the motor control device A controls these motors 7, 17, It controls the number of rotations (speed) of 31.33.

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

In the figure, a control circuit 39 is a control means.

A CPU 41, which is the main element that achieves the functions described later, and a ROM 4 that stores an operating program for this CPU 41.
3, a RAM 45 that temporarily stores data in the calculation process of the CPU 41, and an interface for data input/output (
Ilo) 47 etc.

It is the main part of a so-called microcomputer.

The master-slave relationship setting device 49, mode switching device 512, rotation speed setting device 53, and rate of change limit setting device 55 connected to the control circuit 39 are connected to a keyboard 57 formed on the operation surface of the main body of the device, as shown in FIG. It is formed of
Details will be described later.

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

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

The rotation speed measuring device 67 is the rotation speed detection sensor 9 shown in FIG.
, 19, 35.37 including motor 7.17.31.33
It outputs an analog electrical signal according to the rotation speed of the
It is connected to the control circuit 39 via an A/D conversion circuit 69 that converts an analog signal into a digital signal and outputs a measured rotational speed signal.

The D/A conversion circuit 71 converts the digital rotational 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 in FIG.
．． 1? , 31 and 33 to output a rotation speed command signal.

The change rate IJ limit setting device 55, under the control of the control circuit 39, determines the change time until the maximum range (maximum rotation speed) is reached for each motor 7.17, 31.33. , 31, 33, and each change rate limit value is stored in a change rate limit storage circuit 63.

The rate-of-change limit storage circuit 63 is capable of storing an initial setting value as a first rate-of-change limit value, a reset value as a second rate-of-change limit value, etc., as will be described later.

How to set the rate of change limit value for each motor.

For example, this is done using the motor system setting screen shown in FIG.

That is, the change rate limit values input from the change rate limit setting device 55 for all of the plurality of motors CHI to CH12 are controlled by the control circuit 39.

"Change rate limit [seconds/FS]" is input and displayed in the corresponding column and initialized in any range, for example from 0 to 999 (seconds/FS).The 60 for motor CHI means that the motor CHI is 60. It is set so that it does not change rapidly beyond (seconds/FS).

Incidentally, the motors CHI to CH12 in FIG.

For example, each motor 7.17, 31.33 in FIG.
The same applies to the following description.

Further, as shown in FIGS. 5 and 6, it is also possible to reset the settings within the range of the above-mentioned initial settings using the setting screens for each of the nine motors.

FIG. 5 is a screen for setting the automatic operation mode of a plurality of motors, and FIG. 6 is a speed setting screen for each motor in manual mode. .

Under the control of the control circuit 39, the "rate of change limit [seconds/FS]
) to reset the settings by inputting and displaying them in the relevant column of J.

The master-slave relationship setting device 49 changes the settings of the master-slave relationship of which of the motors in FIG. 2 (motors CH-CH12 in FIG. 4) becomes the main motor and which becomes the slave motor for the main motor. It is something to do.

Regarding the master-slave relationship, using the motor system setting screen shown in FIG. The information is stored in the memory circuit 59, and a plurality of motors can be set as main motors, and one or more slave motors can be slaved to each of the main motors, or another slave motor can be slaved to a slave motor that is slaved to the main motor.

In the column of "Main motor" in Fig. 4, the motor CHI for which "0" is input is the main motor, the motor CH2 for which "l" is input is the slave motor subordinate to the main motor CHI, and "2" is the motor CH2 that is subordinate to the main motor CHI. The input motor CH3 indicates a slave motor subordinate to the slave motor CH2.

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

The mode switching device 51 is configured so that the motor control device A controls each motor 7.
．． This is to set whether to control 17.31.33 in independent operation or ratio operation mode, and is configured so that manual mode and automatic mode can be selected under individual operation and ratio operation modes, respectively. It will be displayed as shown in the operation mode column in Figure 5.

The manual mode in the independent operation mode is to individually control each motor 7.17, 31.33 with the rotation speed input from the rotation speed setting device 53 under the control of the control circuit 39, and the automatic mode in the independent operation mode The mode is set for each motor 7, 17, 3 at the rotation speed input in advance from the rotation speed setting device 53.
1.33 are individually and automatically controlled.

For example, as shown by rlcHJ in FIG.

After 3 stages of automatic operation, the automatic operation setting value is 24o [rpm]
).

The ratio mode of operation is under the control of control circuit 39.

For the main motor, the specified rotation speed is used, and for the slave motor, the ratio is calculated from the rotation speed of the main motor to which this slave motor is dependent. , ·31°33 rotation speed is controlled.

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

The control circuit 39 is in a situation where the mode switching device 51 selects the manual mode in independent operation.

From the rotation speed setting device 53 to each motor 7.17, 31°33
When the rotation speed is input, each rotation speed signal is directly input to D/
Output to the A conversion circuit 71 and the rotation speed storage circuit 61
The number of revolutions is memorized.

When the mode switching device 51 selects the automatic mode in independent operation, the rotation speed 2 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 out and the rotation speed of each motor 7.17 is read out. A rotation speed signal of .31.33 is output to the D/A conversion circuit 71 in a predetermined procedure.

When the mode switching device 51 selects the ratio operation mode, the control circuit 39 refers to the master-slave relationship data stored in the master-slave relationship storage circuit 59 and outputs the measured rotational speed signal from the A/D conversion circuit 69 or D The rotation speed ratio of the main and slave motors is calculated from the signal related to the most recent speed command signal sent to the /A conversion circuit 71 (a digital signal that is essentially equivalent to a speed command signal), and based on the speed setting for the main motor. The rotation speed of each main motor is calculated, and the rotation speed of the slave motor is calculated from the rotation speed of the main motor according to the rotation speed ratio, and outputted to the D/A conversion circuit 71, and the rotation speed is stored in the 2 rotation speed storage circuit 61. It has a memory function.

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

This comparison function with the rate of change limit value is performed in the same way in both automatic mode and manual mode, and the rate of change limit value read from the rate of change limit storage circuit 63 is given priority to the reset value, and the reset value does not exist. If not, the initial setting value is read and compared.

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

When the program starts with the mode switching device 51 setting 9, for example, the ratio operation mode, 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 the rotation speed in step 201. The rate of change limit value S is fetched from the rate limit storage circuit 63, and in the subsequent step 202, it is compared and determined whether or not the rotational speed change rate (2) exceeds the rate of change limit value S.

This rate of change limit value S is stored in the rate of change limit storage circuit 63.
If there is a reset value, the reset value.

If the reset value does not exist, it is compared with the initial setting value.

For example, if the change rate limit value S is 400, the rotation speed change rate V
is 500, step 202 is YES because the one-rotation speed change rate ■ is slower than the change rate limit value S (V≧S).
Then, the process moves to step 204, and the change rate limit value is 4.
If the rotation speed change rate ■ is 300 at 00, the rotation speed change rate ■ is faster than the change rate limit value S (v<3).
, step 202 becomes NO, and the process moves to step 203.

In step 203, the rotation speed change rate A is replaced with the change rate limit value S, and in step 204, the value obtained by adding the amount of change to the old (previous) rotation speed is set as the new rotation speed of motor n.
At 05, the control circuit 39 controls the speed command signal output circuit 73 so that the motor n rotates at the new rotation speed, and the process ends.

〔Effect of the invention〕

As explained above, the motor control device of the present invention is provided.

The control means calculates the rotation speed change rate of each motor and compares it with a preset change rate limit value, and when the rotation speed change rate exceeds the change rate limit value, the rotation speed is changed using the change rate limit value as the rotation speed change rate. Since the rotation speed command signal to the motor is controlled so as not to exceed the rate of change limit, all arbitrary morphs in the extrusion line can be driven within a range that does not exceed the rate of change limit. This makes it easy to perform proper and stable motor control that takes into consideration the entire extrusion molding line when starting up or shutting down the molding line.

Therefore, failures in mechanical systems such as extruders and bow machines are avoided, and abnormalities are less likely to occur in the extrusion molding line.

In particular, the present invention is suitable when a large number of motors are to be controlled and motors without a change rate limiter are used.

In a configuration that stores multiple rate of change limit values, 1
It is possible to arbitrarily set change rate limit values at various stages, such as during manufacturing and operation of the device, to accommodate various types of molding.

Furthermore, in a configuration in which the rotation speeds of the main and slave motors are controlled by the rotation speed change rate of the slave motor during ratio operation,
During ratio operation, the rate of change IJ is strictly controlled based on the rotation speed of the slave motor, allowing for safe operation in the - layer.

[Brief explanation of drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention, and FIG. 2 is a schematic diagram showing an example of an extrusion molding line including the motor control device of the present invention. FIG. 3 is a block diagram showing an embodiment of the motor control device according to the present invention, and FIGS. 4 to 6 show screens for setting the rate of change limit value in the present invention. FIG. 7 shows details of the present invention. This is a flowchart explaining the process. ■・・・・・・・・・・・・・・・Extruder 3...
・・・・・・・・・・・・・・・Molding machine stand 5・・・・・・
・・・・・・・・・－・・・・・・Main Screw-7・・・・
・・・・・・・・・・・・Extrusion motor 9.19,
35.37 Sensor 13 Subscrew 15 Raw material feeder Device 17......Feeder motor 25......
・・Molded product 27.29・・・・・・・Take-up machine

Claims (3)

[Claims] (1) A plurality of motors disposed in an extrusion molding line including an extruder, a rotation speed command means for commanding rotation speeds to the plurality of motors, and a change that stores a rotation speed change rate limit value for each of the motors. A rate limit storage means and a control means for controlling the rotation speed command means, the control means calculating the rotation speed change rate of each of the motors and reading the change rate limit value of each of the motors from the change rate limit storage means. and controlling the rotation speed command means to control the rotation speed change rate of each motor to the change rate limit value when the rotation speed change rate exceeds the change rate limit value. A motor control device for an extrusion molding line featuring: (2) The rate-of-change limit storage means stores a first rate-of-change limit value and a second rate-of-change limit value within a range of constraints of the first rate-of-change limit value. Motor control device for extrusion molding line. (3) The rotation speed command means commands the plurality of motors to rotate at a predetermined ratio as a main motor and a slave motor subordinate thereto, and the control means controls the rotation speed change rate of the slave motors. 3. The motor control device for an extrusion molding line according to claim 1, wherein when the rate of change exceeds the rate of change, the rotation speeds of the main and slave motors are suppressed to the rate of change limit.