JP3537012B2 - Automatic pouring control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic pouring control method in which a ladle is fixed to a pouring machine and tilted to automatically pour molten metal into a mold.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 4-46665 discloses an automatic pouring machine for pouring a ladle so that a desired pouring speed and pouring amount are obtained. This is to control the tilt angle of the ladle by pouring the molten metal stored in the ladle into the mold side from the pouring port by appropriately tilting the ladle supported to be tiltable. In the automatic pouring machine made by the ladle, the driving means for tilting the ladle, the weight detecting means for detecting the total weight of the ladle including the ladle and the molten metal therein, and the output from the weight detecting means A control means for calculating a pouring speed and a pouring amount from a pouring start time based on the pouring speed, and controlling a tilt angle of a ladle by a driving means so as to set the pouring speed and the pouring amount to a predetermined amount set in advance. It is characterized by having.

[0003]

In the above-mentioned known example, a conventional well-known automatic pouring machine sets the shape of a ladle so that its tilting angle and the amount of tapping water have a linear relationship, and the tilting angle of the ladle is changed. The control of the pouring speed and the pouring amount is controlled by the control of the weight, but by controlling based on the change in weight, the tilting angle and the pouring amount use a deformed ladle with no linear relationship. It is also stated that the pouring speed of the molten metal can be maintained at a predetermined value. However, when attempting to control the pouring speed and pouring amount with high precision, the amount of hot water is greatly affected by the shape and tilt angle of the ladle due to the viscosity and mass of the molten metal. Then it is actually difficult. The present invention uses a tilting ladle for storing several tons of molten metal,
The primary purpose is to pouring a ton of molten metal at a high speed of several tens of kg / sec without speed fluctuation as much as possible. Further, automatic pouring can be performed so that the pouring amount is within a range of several kg. It is intended to provide a hot water control method.

[0004]

According to an automatic pouring control method of a tilting type automatic pouring apparatus having a tilting drive means capable of detecting a tilting angle and having a servo controllable tilting means, for each tilting angle of a ladle, The molten metal weight flowing out when the tilting is advanced by a unit angle from the tilting angle is determined and set as a pouring speed, an arithmetic average value of the pouring speed for each tilting angle in a predetermined range is set as an average pouring speed, The value of the pouring speed / average pouring speed at each tilt angle is set as a correction coefficient, and the target pouring speed / average pouring speed is calculated with respect to the presented target pouring speed, and the correction value is calculated. Is set as the first target tilt angular velocity, and a) Until a predetermined time has elapsed from the start of pouring, tilt at the initial target tilt angular velocity obtained by multiplying the first target tilt angular velocity by a predetermined value, b) The predetermined time After elapse, the control target value is C) After that, every time the tilt angle changes, it is updated to the first target tilt angular speed corresponding to it and a new control target value is obtained. It is characterized by controlling the tilt of the ladle

Further, in the automatic pouring control method of the tilting type automatic pouring device having the tilting angle and the tapping weight, and having the tilting drive means capable of servo control, the tilting angle of the ladle is changed for each tilting angle of the ladle. The weight of the molten metal flowing out when tilting is advanced by a unit angle from the tilt angle is determined and set as a pouring speed, and the arithmetic average value of the pouring speed for each tilt angle in a predetermined range is set as an average pouring speed. A value obtained by dividing the pouring speed at the tilt angle by the average pouring speed is set as a correction coefficient, and the target pouring speed is divided by the average pouring speed with respect to the presented target pouring speed, and the correction is performed. The product obtained by multiplying the value is set as the first target tilting angular velocity, and further, the tilting angular velocity calculated from the deviation of the actual pouring weight and the target pouring weight after tapping calculated from the presented target pouring rate. As the second target tilt angular velocity A) Until a predetermined time has elapsed from the start of pouring, tilt at an initial target tilt angular speed which is a predetermined multiple of the first target tilt angular speed. B) After a predetermined time has elapsed, the control target value is tilted at that time. Changing to the first target tilt angular velocity corresponding to the angle, c) thereafter, every time the tilt angle changes, updating to the first target tilt angular velocity corresponding thereto, and adding the second target tilt angular velocity, The new control target value is used, and the tilting of the ladle is controlled based on the new control target value.

[0006]

FIG. 1 shows an overall view of a control system. The pouring machine body 1 is provided with a hydraulic cylinder 2, which is a driving means for tilting the ladle, an encoder 3 for detecting the tilt angle of the ladle, and a load cell 4 for detecting the weight of the ladle including the molten metal. The control personal computer 7 obtains in advance information of the pouring machine control conditions such as the number of pouring molds, the position and the type of the melting furnace to be supplied to the ladle from the host computer 8, the target pouring speed, the target pouring weight, Take in pouring information such as the amount of hot water stored and the type of ladle. Further, it takes in data from the encoder 3, the load cell 4, and the tapping sensor 6 for detecting tapping, and outputs a command voltage to a hydraulic amplifier 5 that controls the speed and the amount of movement of the hydraulic cylinder 2 according to a control algorithm described later.

The control algorithm will be described below. As control for keeping the pouring speed constant, the measured ladle tilt angle is compared with the target ladle tilt angle,
This is encoder feedback control for calculating the output.
The point of the present invention lies in how to make a target ladle tilting angle, which basically calculates a target tilting angular speed from a target pouring speed and further calculates a target ladle tilting angle (target encoder value). Here, the ladle used for pouring is that the hot water storage section shape that has been conventionally used at the casting site is to be used as it is as a cylindrical shape as it is, and based on the various pouring information, an appropriate size The thing is selected and set in the pouring machine,
A predetermined amount of molten metal is supplied from the melting furnace. This ladle has a non-linear characteristic that the pouring speed varies depending on the tilt angle even if the ladle is tilted at a constant tilt angular speed. Therefore, the tilt angular velocity is corrected in accordance with the tilt angle of the ladle so that the molten metal is tilted slowly at an angle at which the molten metal easily comes out, and is tilted quickly at an angle at which the molten metal is hard to come out. Molten metal has viscosity and mass.To collect accurate tilt angular velocity correction data, many experiments with actual molten metal are necessary. It takes time and effort. Therefore, we calculate the pouring characteristics of the ladle from the geometric shape of the ladle,
Approximate tilt angular velocity correction data was created.

[0008] Hereinafter, a method for preparing a ladle having a capacity of 5 tons and an almost cylindrical shape having a diameter of 0.85 m and a height of 1.16 m will be described. First, the shape of the ladle is approximated to a cylinder, and for each tilt angle within a predetermined range set in advance, the amount of hot water discharged when tilted by 1 ° is geometrically calculated, and it is calculated at a tilt angular velocity of 1 ° / sec. It is the pouring speed at the tilt angle.
FIG. 2 is a graph showing an example of a calculation result in the range of 0 to 90 °. Next, an average value is obtained from the pouring speed for all tilt angles. In this example, it is 26.8 kg / sec. With this as a reference value 1, a conversion value at each tilt angle is calculated. The reciprocal of the calculated value was used as a tilt angular velocity correction coefficient corresponding to each tilt angle specific to the type of ladle. FIG. 3 shows a part of the result of the above calculation based on the pouring speed shown in FIG. The first row is the tilt angle (θ), the second row is the pouring speed (Vcal) when tilting at a tilt angular velocity of 1 ° / sec calculated from the geometrical shape, and the third row is the pouring speed / The average speed in the fourth column is the reciprocal of the third column, which is the correction coefficient (K (θ)).

The data is calculated and filed for all types of ladles to be used. At the time of actual pouring, a file corresponding to the input ladle type is opened, and a target pouring speed and a target tilting angular speed corresponding to the ladle tilting angle are calculated and used. For example, if the target pouring speed is 5
Assuming that the pressure is 0 kg / sec, the average pouring speed at 1 ° / sec is 26.8 kg / sec from FIG. 3. Therefore, first, a provisional tilt angular velocity 50 ÷ 26.8 = 1.87 ° / sec is calculated. . When the tilting is started from the tilting angle of 40 °, the correction coefficient is 1.01, and 1.01 × 1.87 = 1.88 ° / sec is calculated, and this is set as the first target tilting angular velocity. That is,
The first target tilt angular velocity is defined as follows. First target tilt angular velocity = Target pouring speed ÷ Average pouring speed × Correction coefficient During pouring, the first target tilt angular velocity in which the correction coefficient is updated every tilt angle 1 ° measured by the encoder 3 is used. .

[0010]

Next, an embodiment of the automatic pouring control method of the present invention will be described. In the present embodiment, the ladle is used, and the target pouring amount is sequentially poured into four molds having a target pouring amount of about 600 kg at a target pouring speed of 50 kg / sec and a target pouring amount variation of 6 kg. At this time, it is assumed that the hot water is discharged from the tilt angle of 40 °. Here, pouring is performed at the target pouring speed of 50 kg / sec until pouring is completed, and when the ladle is inverted at the end, the weight of the molten metal flowing out during the inversion is large and the dispersion is large. Can not be obtained. Therefore, at the end of the pouring of the part relating to the casting of the actual product, for example, is almost completed, and at the time of the pouring step to the feeder or the runner, once a small reversal,
Thereafter, the second pouring is performed with the pouring speed reduced, and finally, the control is performed at a two-stage pouring speed such that complete inversion is performed.

Hereinafter, description will be made sequentially with reference to FIG. First, the ladle initial angle is naturally set to be smaller than 40 °, for example, 37 ° to prevent the molten metal from spilling. Therefore, an initial target tilt angular velocity was set in order to tilt from 37 ° to 40 ° in as short a time as possible. In this example, the initial target tilt angular velocity was set to twice the first target tilt angular velocity (set appropriately according to the target pouring speed). That is, 3.8 ° / sec, which is twice the above-mentioned 1.88 ° / sec, was set as the initial target tilt angular velocity.

At 15, at the same time that the tapping sensor 6 detects tapping from the ladle, the control personal computer 7 resets the weight value. Since the molten metal outflow speed at the beginning of tapping is low, in order to reach the target pouring speed quickly, a predetermined several seconds indicated by 20 (appropriately set according to the target pouring speed) is the initial target tilting angular speed of 3.8 ° /. Hold seconds. After the predetermined time, the target tilt angular velocity is changed from the initial target tilt angular velocity to the first target tilt angular velocity calculated from the initial target pouring speed. At this time, if the ladle is tilted to, for example, 45 °, the first target tilt angular velocity is 0.88 × 1.87 = 1.65 ° / sec based on the correction coefficient shown in FIG. During the period 21 thereafter, the ladle is decelerated while updating the first target tilt angular velocity corrected for the tilt angular velocity based on the correction coefficient every time the tilt angle changes by 1 °.

During this time, the load cell data is continuously monitored to determine whether the weight has reached a preset weight (set appropriately according to the target pouring speed). The set weight is a weight that reaches a point at which a change in the load cell measurement value due to a rapid change in the tilt angular velocity stops. The section indicated by 22 after 16 when the set value is detected is an important section that actually determines the quality of the product section, and is a zone where the pouring should be performed at the target pouring speed.
During this time, the second target tilting speed which is the tilting angular speed by weight feedback using the actual pouring speed calculated from the temporal change of the pouring weight measured from the load cell 4 as the first target tilting speed. To provide encoder feedback. Details of the control will be described later.

Thereafter, at a time 17 when the pouring weight is obtained by subtracting a preset first weight (appropriately set according to the product to be cast) from the target pouring weight, the pouring speed is converted into a predetermined pouring speed. In this example, the first weight is set to 100 kg, and the small inversion is performed. This inversion is performed at a predetermined speed at a predetermined angle. For example, if the hot water may be drained, the angle may cause the hot water drainage. If the hot water drainage causes a failure, be careful not to cause the hot water drainage by the start of the next second pouring. The inversion angle is set to be small, and the pouring speed is set to be small.

A predetermined time 23 from when the small inversion is started to when the predetermined inversion angle is reached and until the influence of the recoil due to the small inversion on the load cell is eliminated, the same control as in the section 21 is performed. During this time, the amount of hot water is not constant because the tilting angular velocity until immediately before the small inversion is large. From the time point 18 after the lapse of the predetermined time, the section of the second pouring indicated by 24 is similar to the control performed in the section 22,
Perform tilt angular velocity control with weight feedback.
In this section, the pouring speed in the product section is almost a fraction of the target pouring rate, since the main purpose is to fill the final pouring volume to the target value, since the pouring into the so-called hot water section where the pouring of the product section is almost completed. Is set in advance. In this embodiment, it is 10 kg / sec.

Then, at time 19, when the pouring weight is obtained by subtracting the second predetermined weight from the target pouring weight,
The ladle is inverted by returning the ladle at a preset constant inversion speed by a preset angle, and the pouring is completed. At this time, the weight flowing out during the reversal must match as much as possible the second weight set in advance. The inversion speed and the second weight set value for that purpose are related, and the inversion speed is made constant, the second weight set value may be determined for each ladle, or the second weight set value is made constant and the inversion is performed. The speed may be determined for each ladle. In the present example, the second weight set value was fixed at 30 kg. FIG. 5 shows the result of pouring continuously into different molds. Although the target pouring amount differs from the pouring start angle of the ladle, the error of the final pouring amount is very small, and it can be seen that the pouring is accurate.

Next, the pouring speed control will be described with reference to the block diagram of FIG. For a target encoder value of 30,
The actual ladle tilt angle measured by the encoder 3 is fed back, and the hydraulic cylinder 2 is controlled to control the ladle tilt angle. Using the ladle-specific file described above to generate the target encoder value 30, a path based on the tilting angular velocity corrected from the target pouring speed and the ladle tilting angle is indicated by a dotted line 36. A path for calculating the target pouring weight from the target pouring speed and calculating the tilt angular velocity from the weight feedback comparing the pouring weight from the load cell is added.

First, when weight feedback by the load cell is not used (in FIG. 4, sections 20, 21, and 23).
Will be described. Set target pouring speed 33
At 32, the tilt angular velocity is corrected using the correction value calculated according to the tilt angle (θ) of the ladle as described above, and the first target tilt angular velocity 31 is calculated. The calculation formula is shown in the following formula 1. mmv (θ) = V / Vave × K (θ) (1) where mmv (θ): first target tilt angular velocity (゜ / s) V: target set in advance Pouring speed (kg / s) Vave: Average calculated pouring speed at 1 ° / s tilting angle speed (kg / s) K (θ): Correction coefficient Target encoder value 30 calculated from first target tilting angular speed 31 And the deviation from the actually measured encoder value is subjected to known feedback processing, for example, PID processing, and output to the hydraulic amplifier 5. The hydraulic amplifier 5 includes the hydraulic cylinder 2
For example, a voltage is output to a servo valve (not shown) that controls the speed of the motor. Here, the relationship between the hydraulic cylinder speed with respect to the ladle tilting angular speed and the voltage is determined and set in advance.
As a result, the hydraulic cylinder 2 is subjected to encoder feedback control. As described above, since the correction coefficient is updated each time the tilt angle changes by 1 °, the first target tilt angular velocity changes accordingly.

Next, the control of the section where the weight feedback is added by the load cell (sections 22 and 24 in FIG. 4) will be described. First, set target pouring speed 3
3 is compared with the pouring weight 35 measured by the load cell, the deviation calculated by the following equation 2 is calculated according to the equations 3 and 4, and the deviation from the load cell value shown by the equation 4 is calculated. A second target tilt angular velocity is calculated. e = mj−rmj (2) se = Σe (3) ie = Kp × (Ki × se + e) (4) where e: deviation mj : Preset target pouring weight (kg) rmj: Measured pouring weight (kg) se: Total of deviation ie: Second target tilt angular velocity (゜ / s) Kp: Weight / speed conversion with proportional element Coefficient Ki: Integral coefficient or more. From Equations 1 and 4, the periods 22 and 24 shown in FIG.
Is expressed by the following equation (5). mv = ie + mmv (θ) (5)

In this embodiment, a target encoder value is calculated from the target tilt angular velocity every 20 milliseconds, and a feedback signal is output to the hydraulic amplifier in comparison with the measured value of the encoder. When weight feedback is added, 1
The load cell measurement value is measured every 00 milliseconds, and the target tilt angular velocity is corrected as described above.

FIG. 7 shows a change in pouring weight in the case where the tilting angular velocity is not corrected based on the ladle shape but is controlled only by weight feedback, and FIG. 8 shows the result of the control according to the present invention. The target pouring speed at this time is 30 kg / sec.
This is data of the section from 20 to 22 in FIG. From FIG. 7, it can be seen that the pouring speed is large in the first half and small in the second half, and it is not possible to maintain the pouring speed with high accuracy even though the feedback is performed only by the feedback based on the weight. On the other hand, FIG. 8 shows that the pouring speed is almost constant.

It should be noted that the present invention is not limited to the above-described explanation range, but is calculated from the tilt angular velocity correction using a file in which the above-described ladle-specific correction coefficients and the like are calculated depending on the pouring specifications. It is also possible to cope with only the encoder feedback control based on the target encoder value or the control in which the weight monitoring is added thereto. The conversion of the pouring speed in the section indicated by 23 is to change the tilting angle direction and the tilting angle change per unit time, and not only the inversion but also the second pouring after the pause or directly. The operation to move to is also included. Further, not only the second pouring but also a third pouring or more may be added. In addition to controlling the second pouring and thereafter while rotating forward as shown by the section 24 in FIG. The control may be performed while reversing. Also,
The calculation of the ladle correction coefficient is performed by selecting a container shape that is similar to the actual shape of the ladle hot water storage section, but ultimately the container shape is appropriately adjusted based on the actual pouring data. You may change all or some and recalculate. The sampling cycle of the feedback can be determined as appropriate, and the ladle tilting means can be applied not only to the hydraulic cylinder but also to a hydraulic motor, an electric motor or any other device capable of servo control.

[0023]

As described above, according to the automatic pouring control method of the present invention, the correction coefficient based on the shape of the ladle to be used is set in advance, and the ladle tilt angular velocity is set for each tilt angle. Since the correction is performed, the influence of the viscosity and mass of the molten metal can be reduced, and the pouring speed of the molten metal can be maintained at a predetermined value even when using a ladle in which the tilt angle and the amount of molten metal do not have a linear relationship. In addition, since the correction coefficient is calculated from the ladle hot water storage unit by geometric calculation, it is not necessary to perform an enormous and troublesome experiment, and a large number of data according to the conditions are obtained, and the change is easy. Further, in addition to the calculation of the first target tilt angular velocity by the ladle tilt angular velocity correction based on the correction coefficient, the second target tilt angular velocity is calculated from the weight feedback that measures the actual pouring amount, and the target tilt angular velocity is calculated. Since the tilt angle data is updated, the pouring speed with little fluctuation can be realized.

[Brief description of the drawings]

FIG. 1 is an overall view of a control system.

FIG. 2 is a graph for explaining a tilt angular velocity correction method;

FIG. 3 is an example of a file in which ladle-specific correction factors and the like are described.

FIG. 4 is an example of a tilt angular velocity pattern diagram

FIG. 5 is an example showing an error between a target pouring amount and an actual pouring amount.

FIG. 6 is a block diagram of a control system.

FIG. 7 is a graph showing a change in pouring weight without tilt angular velocity correction;

FIG. 8 is a graph showing a change in pouring weight when tilting angular velocity is corrected;

[Explanation of symbols]

1 ... pouring machine, 3 ... encoder, 4 ... load cell, 7
... Control personal computer 15 ... Hot water start point, 16 ... Feedback start point,
17 ... Small reversal start point 18 ... Second pouring speed, 19 ... Holding reversal start point

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-133969 (JP, A) JP-A-53-72738 (JP, A) JP-A-62-57758 (JP, A) 344125 (JP, A) JP-A-6-262342 (JP, A) JP-A 63-47062 (JP, U) JP-A 64-38161 (JP, U) (58) Fields investigated (Int. ⁷ , DB name) B22D 39/04 B22D 11/18 B22D 41/06 G05D 7/00

Claims (2)

(57) [Claims] 1. A tilting-type automatic pouring control method including means for detecting a tilting angle and a tapping weight and having a tilting drive means capable of being servo-controlled, wherein for each tilting angle of a ladle, a unit angle is calculated from the tilting angle. The weight of the molten metal flowing out when only tilting is advanced is set as the pouring speed, the arithmetic average value of the pouring speed for each tilt angle within a predetermined range is set as the average pouring speed, and the pouring at each tilt angle is performed. The value obtained by dividing the speed by the average pouring speed is set as a correction coefficient, and the target pouring speed is divided by the average pouring speed with respect to the presented target pouring speed, and the product is multiplied by the correction value. Is set as the first target tilting angular velocity, and the tilting angular velocity calculated from the deviation between the target pouring weight after tapping calculated from the presented target pouring rate and the actual tapping weight i) is used as the second target tilting angular velocity. Set the target tilt angular velocity of Until a predetermined time has elapsed from the start, the tilt is performed at an initial target tilt angular speed obtained by multiplying the first target tilt angular speed by a predetermined value. B) After a predetermined time has elapsed, the target tilt angular speed is set to a first value corresponding to the tilt angle at that time. After that, every time the tilt angle changes, the target tilt angular velocity is updated to the first target tilt angular velocity, and the second target tilt angular velocity is added to obtain a new target tilt angular velocity. Automatic pouring control method characterized by controlling the tilt of the ladle based on 2. The automatic pouring control method according to claim 1, wherein: (a) tilting is performed at an initial target tilt angular velocity obtained by multiplying the first target tilt angular velocity by a predetermined value until a predetermined time has elapsed from the start of pouring; After a predetermined time has elapsed, the target tilt angular velocity is changed to a first target tilt angular velocity corresponding to the tilt angle at that time, and tilt control is performed. And the second target tilt angular velocity is added to perform tilt control as a new target tilt angular velocity. D) When a preset first hot water supply amount is reached, a preset time and a preset tilt angle are applied. E) After the set time has elapsed, a new first target tilt angular velocity and a new target tilt angular velocity are calculated by using another preset pouring speed as a new target pouring speed, and the tilt angle is calculated. Every time it changes The tilt angle is updated to the first target tilt angular velocity corresponding to the above, and the second target tilt angular velocity is added to perform tilt control as a new target tilt angular velocity. Automatic pouring control method characterized by performing.