JP4282066B2 - Automatic pouring control method and storage medium storing ladle tilt control program - Google Patents

Description

The present invention relates to an automatic pouring control method and a storage medium storing a ladle tilting control program, and more specifically, by a servo motor controlled by a computer set in advance to execute a pouring process. A method of tilting the ladle to control automatic pouring from the ladle to the hanging weir to avoid overflow of molten metal from the hanging weir and insufficient flow rate of molten metal injected into the mold, and tilt control for the ladle The present invention relates to a storage medium storing a program.

In recent years, mechanization and automation of the pouring process has been carried out in order to relieve workers from the most dangerous and worst work like pouring in a foundry. And conventionally, as a device for this, the ladle, the drive means for driving the ladle, the detection means for detecting the weight of the ladle, and the weight in the ladle when the ladle is tilted in advance. There is a storage operation device that stores a fluctuation ratio, corrects the tilting speed of the ladle corresponding to the signal from the detection means, and transmits the corrected tilting speed signal to the driving means. (For example, refer to Patent Document 1).
JP-A-6-7919

By the way, in the conventional automatic pouring apparatus configured as described above, information relating to the driving means and the like is input to the storage arithmetic device by the teaching & playback method. However, with such a method, the upper surface position of the molten metal in the hanging weir is not stable due to the inability to counter the inappropriate ladle tilting speed and changes in the pouring situation, and the molten metal overflows from the hanging weir. The molten metal injected into the mold becomes insufficient in flow rate, and impurities such as dust and sludge are swallowed into the mold during pouring, leading to deterioration of the casting quality. It is not possible to perform advanced control such as suppression of molten metal surface vibrations or prediction of molten metal flow rate at the end of pouring, and in addition, it is indispensable to input information related to periodic pouring, so production efficiency is poor. There were problems such as.

The present invention has been made in view of the above circumstances, and its purpose is by tilting the ladle, which can be brought as close as possible to pouring work by a skilled worker by a computer in which a program is set in advance. An object of the present invention is to provide a storage medium storing a control method for automatic pouring and a tilt control program for a ladle.

In order to achieve the above object, an automatic pouring control method according to claim 1 is a computer which stores in advance a program using a control system using a model method and applying supervisory control to perform a pouring process. The ladle is tilted by the servo motor controlled by the control of the automatic pouring from the ladle to the hanging weir to avoid overflow of the molten metal from the hanging weir and insufficient flow rate of the molten metal injected into the mold. Injecting the molten metal by inclining the ladle containing the molten metal to the hanging weir side and injecting the molten metal so that the upper surface thereof is quickly raised to the target level within a range where the molten metal does not overflow from the hanging weir. the launch, pouring adopts feed-forward control system to the step of maintaining substantially constant the position of the upper surface of the molten metal in the Kakeseki with launching, the ladle after the end of the launch of pouring the The between time tilting to the opposite side of the KiKakeseki, controlled by 2-degree-of-freedom control system obtained by adding a feedback control system in the feed forward control system, flows out of the ladle at the end of the start-up of the pouring The hanging weir of the ladle to inject the molten metal into the hanging weir so that the amount of molten metal and the amount of molten metal flowing into the mold are substantially equal and the upper surface position of the molten metal in the hanging weir is maintained substantially constant The timing of switching the tilting from the tilting to the hanging weir side to the countering weir side according to the ladle, the weight information of the molten metal in the hanging weir and the hanging weir of the ladle determined by predictive control the melt weight predicted to finally pouring the runoff chase after the molten metal from the ladle based on the tilt angle information to the side, then the anti of the ladle The tilting to the hanging weir side is controlled by the hybrid shaping method. The molten metal in the ladle, characterized in that to end the pouring perform opposite is tilted hot cut into the ladle so as not to generate sloshing the Kakeseki.

effect

As is apparent from the above description, the present invention is a servo motor controlled by a computer that pre-stores a program using a control system using a model method and applying supervisory control to perform a pouring process. The ladle is tilted to control the automatic pouring from the ladle to the hanging weir to avoid overflow of the molten metal from the hanging weir and insufficient flow rate of the molten metal injected into the mold. the ladle incoming launched pouring and injecting the molten metal so as to increase quickly the upper surface to the extent that the molten metal does not overflow from the Kakeseki is tilted to the hanging dam side to the target level, pouring A feed-forward control system is used to maintain the top surface position of the molten metal in the hanging weir almost constant, and the ladle is tilted to the opposite side of the hanging weir after the start of pouring. Is controlled by a two-degree-of-freedom control system in which a feedback control system is added to the feedforward control system, and the amount of molten metal flowing out of the ladle at the end of the pouring of the molten metal and flowing into the mold The ladle continues to tilt toward the hanging weir to inject the molten metal into the hanging weir so that the amount of the molten metal is substantially equal and the upper surface position of the molten metal in the hanging weir is maintained substantially constant. The timing of switching the tilt from the tilt to the hanging weir side to the hanging weir side related to the ladle, the weight information of the molten metal in the hanging weir and the tilt angle information of the ladle to the hanging weir side, The amount of molten metal to be poured is predicted and controlled based on the amount of molten metal that is finally poured from the ladle, and the tilt of the ladle toward the counter weir is then determined. molten metal nest of the ladle is controlled by a hybrid shaping method The ladle is tilted to the opposite side of the hanging weir so as not to cause sashing, and the pouring is completed by pouring out the hot water. There are excellent practical effects such as automatic pouring with a ladle in a state where it is as close as possible.

The model method used in the present invention is to solve the equations of process heat balance, material balance, chemical reaction, limiting conditions, etc. It is a method of seeking and controlling so that it can be achieved.
Furthermore, in the present invention, by using a ladle having a vertical cross-sectional shape that is fan-shaped and supported so as to be tiltable at the center of gravity, the ladle is suitable for small-lot production and the equipment itself is small. can do.

In addition, in the present invention, the position of the upper surface of the molten metal in the hanging weir can be quickly adjusted by adopting a feedforward control system in the process of starting the molten metal and maintaining the position of the upper surface of the molten metal in the hanging weir almost constant. It can be raised to the target level and thereafter the upper surface position of the molten metal in the hanging weir can be maintained substantially constant.
Here, feed-forward control is a control method that adjusts the amount of operation applied to a control target to a predetermined value so that the output becomes a target value. When the influence of the above is clear, control with good performance can be performed.

Further, in the present invention, the two-degree-of-freedom control system in which the feedback control system is added to the feedforward control system from the end of the pouring start up to the time when the ladle is tilted to the opposite side of the hanging weir. By controlling by this, it is possible to reduce the fluctuation of the upper surface position of the molten metal in the hanging weir due to the influence of disturbance.
Here, feedback control is a control method that compares the output from the control target with the target value and adjusts the manipulated variable so as to cancel the difference. Effective control can be performed even when there is an unknown disturbance.

Furthermore, in the present invention, by applying the hybrid shaping method to the tilting of the ladle, feedback is not performed on the upper surface vibration of the molten metal in the ladle, and only the feedback control with respect to the position of the drive system of the tilting shaft of the ladle is performed. The positioning control can be performed at high speed without causing vibration on the upper surface of the molten metal.
Here, the hybrid shaping method limits the control system to a simple set of elements, incorporates quantitative design specifications of time characteristics and frequency characteristics into the control system design, and does not perform on-line measurement or feedback of vibration. The position of the object is controlled so as not to generate residual vibration.

In addition, in the present invention, the timing of switching the tilt from the hanging weir side to the counter hanging weir side according to the ladle, the weight information of the molten metal in the hanging weir and the tilt angle of the ladle toward the hanging weir side By performing the predictive control for predicting the follow-up outflow amount of the molten metal from the ladle based on the information, the molten metal can be finally poured with high accuracy.
Here, predictive control refers to predicting how the future output behaves using the past control input and the past output up to the present time, so that the predicted value becomes the target value. This is the control that determines the control input. This control method is used when the characteristics of the object of optimization control are known in advance and a fairly accurate mathematical model is created.

In addition, in the present invention, by controlling the tilting of the ladle to the side of the hanging weir by the above-described hybrid shaping method, it is possible to suppress sloppy without using a large number of sensors.

Hereinafter, an embodiment of an automatic pouring device to which the present invention is applied will be described in detail with reference to FIGS. As shown in FIG. 1, the automatic pouring apparatus includes a sector ladle 1, an AC servo motor 2 as a tilting means for tilting the sector ladle 1, the sector ladle 1 and the AC servo motor 2. Three sets of ball screw mechanisms 3 to 5 for converting the rotational movement of the output shaft of the AC servo motor to linear movement as moving means for three-dimensional movement, and the weight of the molten metal in the sector ladle 1 are detected. A load cell 6 as detection means; a control system 7 for calculating and controlling the operation of the AC servo motor 2 and the three sets of ball screw mechanisms 3 to 5 using a computer; and a molten metal in the sector ladle 1 And a laser displacement sensor 10 for detecting the upper surface level.

The sector ladle 1 connects the output shaft of the AC servo motor 2 to the center of gravity of the ladle 1 and supports it so that it can tilt in the T-axis direction at the center of gravity. It tilts and counter-tilts with respect to the hanging weir 9 installed on the upper surface of the mold 8. In addition, by tilting about the center of gravity position, it is possible to prevent the load applied to the AC servomotor 2 from becoming large, and in addition, the fan ladle 1 is moved to the opposite side of the hanging weir 9. When the hot water is cut off by tilting, the molten metal slooding in the sector ladle 1 can be suppressed.

Further, the three sets of ball screw mechanisms 3 to 5 are arranged so that the AC servo motor 2 supporting the sector ladle 1 is perpendicular to the X axis in the X axis direction parallel to the moving direction of the mold 8 and in the horizontal plane. The Y-axis direction and the Z-axis direction in which the fan-shaped ladle 1 moves up and down are reciprocated. The position and tilt angle in the three-dimensional space related to the sector ladle 1 can be measured by a total of four rotary encoders attached to each AC servo motor.

In this automatic pouring apparatus, the transfer function from the input voltage on the T-axis, X-axis, Y-axis, and Z-axis to the position of the sector ladle 1 is used as a first-order lag system + integrator. Express as follows.

Here, K _m is a motor gain, and T _m is a time constant. These are applied to each of the T-axis, X-axis, Y-axis, and Z-axis AC servo motors in a step-like manner, and simulation results and experimental results. And so that they are equal.

The fan ladle 1 is equipped with two stainless steel electrodes having a diameter of 2 mm as a sensor for measuring the behavior of the molten metal, and the change in the upper surface position of the molten metal is taken as a change in resistance between the two stainless steel wires. By capturing, the position of the upper surface of the molten metal is detected.

The control system 7 includes a program for tilting the sector ladle 1 by driving the AC servo motor 2 and the three sets of ball screw mechanisms 3 to 5 and performing a pouring process using a model method. Data is stored.

Next, the operation of the automatic pouring apparatus configured as described above will be described. After charging the required amount of molten metal into the sector ladle 1 and operating the automatic pouring device via the control system 7, the AC servo motor of the X-axis ball screw mechanism 3 rotates in the forward and reverse directions to form a sector-shaped ladle. After the pan 1 moves to a required position corresponding to the hanging weir 9, the sector ladle 1 tilts to perform the pouring process.

In this pouring process, as shown in FIG. 2, the upper surface of the pouring ladle 1 with the molten metal is raised to the target level quickly as long as the molten ladle 1 tilts toward the hanging weir 9 and the molten metal does not overflow from the hanging weir 9. Then, the molten metal is injected to start up the molten metal, and the amount of molten metal flowing out from the sector ladle 1 and the amount of molten metal flowing into the mold 8 at the end of the molten metal pouring are almost equal and the inside of the hanging weir 9 The pouring ladle 1 continues to tilt toward the hanging weir 9 side so as to inject the molten metal into the hanging weir 9 so that the upper surface position of the molten metal is maintained substantially constant, and then the molten metal in the fan-shaped ladle 1 does not generate sloshing. In this way, the sector ladle 1 is tilted to the opposite side of the hanging weir 9 to perform hot water cutting and finish pouring.

Since this pouring process is complicated as shown in FIG. 2, the control system 7 uses a control system to which supervisory control as shown in FIG. 3 is applied.

Here, u is the tilt input of the sector ladle 1, and y is the expression y ^T = [θ M
h _c ] is an observation output given by (4), w is an external disturbance, and σ is a switching signal given by the formula σ ^T = [σ ₁ σ ₂ ] (5). Where θ is the tilt angle of the sector ladle 1
M is the weight of the molten metal in the sector ladle 1, and h _c is the upper surface level of the molten metal in the sector ladle 1.

When the above-described supervisory control is applied, in the process of maintaining the top surface position of the molten metal in the hanging weir 9 substantially constant after starting the pouring in the series of pouring processes described above, The top surface position of the molten metal is controlled by a feedforward control system.

Further, when the above-described supervisory control is applied, if the pouring situation changes due to a dimensional error of the mold 8 or clogging of a runner, etc., the above-described feedforward control alone will cause the inside of the hanging weir 9 The upper surface position of the molten metal cannot be kept constant. Therefore, when fluctuations occur in the upper surface position of the melt due to the influence of some disturbance, a control system is added to the two-degree-of-freedom control system in which a feedback control system effective for reducing the influence of the disturbance is added to the feedforward control system. It changes and it controls so that the upper surface position of the molten metal in a hanging weir becomes healthy with respect to the change of the pouring situation. For this reason, the control system 7 applies _H∞ robust control to the feedback control system.

Here, the _H∞ robust control is a well-known and well-known advanced control. A brief description is given below. The mathematical model of the process has inaccuracies in parameters, etc., and it is often the case that the model considered by the designer is inconsistent with the actual phenomenon, but the maximum modeling error (worst case) should be included in the design specification. Even if the model considered and the actual phenomenon fluctuate within the range of the maximum error, the control does not impair the stability and can obtain a certain degree of control performance. Robust refers to robust control in which the control performance falls within a certain range even if the actual process phenomenon differs from the mathematical model considered within a certain range.

After pouring hot water by tilting the sector ladle 1 to the hanging weir 9 side, hot water cutting is performed by tilting the sector ladle 1 to the counter hanging weir side 8.
In this case, when the above-described supervisory control is applied, the switching timing of the tilting from the side of the hanging weir 9 to the side of the hanging weir 9 on the sector ladle 1 is not excessive or insufficient with respect to the target filling amount. The amount of molten metal in the hanging weir 9 and the tilting angle information of the fan-shaped ladle toward the hanging weir are predicted, and finally the amount of follow-up outflow from the fan-shaped ladle 1 is predicted. It is determined by predictive control of the molten metal weight to be poured.

Furthermore, when the above-described supervisory control is applied, the tilting of the fan-shaped ladle 1 for hot water cutting toward the counter-wetting weir is controlled by the hybrid shaping method.

On the other hand, in this automatic pouring apparatus, since the sector ladle 1 tilts around the center of gravity, the displacement y of the pouring tip of the sector ladle 1 in the Y-axis direction and Z-axis direction that occurs during tilting y _In order to guarantee _n and z _n , as shown in FIG. 3, the sector ladle 1 is moved in the Y-axis direction and the Z-axis direction in accordance with the rotation in the T-axis direction, and the tip of the pouring spout of the sector-shaped ladle 1 is molded. Positioning control is performed so as to be fixed at an upper position of 8.

In this case, the control input is such that the tilt angle θ is first expressed by the equation y _n = r {cos (θ ₀ −θ) −cos (θ ₀ )} (2) and the equation z _n = −r {sin (θ ₀ − θ) −sin (θ ₀ )} Substituting each into (3) to obtain the necessary correction amounts for the Y and Z axes, and then substituting them into the inverse model of equation (1).

Here, θ ₀ is the initial angle at which the pouring tip of the sector ladle 1 forms a horizontal plane, θ is the tilt angle of the sector ladle 1, and r is the rotation center of the sector ladle 1 and the pouring tip of the sector ladle 1. Is the distance.
In addition, during the pouring operation by tilting the sector ladle 1, the molten metal in the sector ladle 1 does not vibrate, so that throttling suppression is not considered, and only the pouring port position is controlled by feedback control.

Next, in order to control the automatic pouring apparatus using the model method, the control system 7 performs simulation analysis. First, in order to rationally obtain a pouring control input that stabilizes the upper surface position of the molten metal in the hanging weir 9, as a first step, pouring from the tilting operation of the molten metal ladle 1 toward the hanging weir 9 to the mold 8 is performed. Modeling of a series of processes up to the flow rate of the hot water and further to the upper surface position of the molten metal in the hanging weir 9 is performed.

The schematic diagram used for explaining the pouring process is as shown in FIG.
Here, ω (t) is the tilting angular velocity of the sector ladle 1, q (t) is the pouring flow rate from the sector ladle 1 to the hanging weir 9, and h _C (t) is the upper surface level of the molten metal in the hanging weir 9. , _h m (t) is a top level of the molten metal in the mold 8, _{a C} is the cross-sectional area of the Kakeseki 9, the _{a M} cross-sectional area of the mold 8, _{a G} is the cross-sectional area of the dam portion 8.

As a modeling procedure, first, a model from the input voltage u (t) to the T-axis AC servomotor 2 to the tilting angular velocity ω (t) of the sector ladle 1 is derived, and then the sector ladle 1 The pouring flow rate q (t) to the hanging weir 9 from the tilt angular velocity ω (t) and the model from the pouring flow rate q (t) to the upper surface level h _C (t) of the molten metal in the hanging weir 9 are sequentially To derive. Finally, they are integrated, and a model of a series of processes from the tilt input of the sector ladle 1 to the upper surface level of the molten metal in the hanging weir 9 is derived.

Note that the model related to the AC servo motor is as shown by the equation (1) as described above.

Moreover, since the fan-type ladle 1 tilts around the center of gravity position in this automatic pouring apparatus, the model relating to the flow rate and the model relating to the upper surface position of the molten metal will be tilted. It is considered that a constant pouring flow rate can be obtained. Therefore, the flow rate model can be described by a first-order lag system represented by Equation (6).

Here, _Kf is a flow rate gain [m ³ / deg], and _Tf is a time constant [s]. The identification of these parameters is obtained by applying a step-like input voltage to the T-axis AC servomotor 2 and measuring the outflow rate at that time.

In FIG. 5, the pouring flow rate q (t) from the sector ladle 1 flows into the hanging weir 9, and the flow rate q _G (t) flows out from the hanging weir 9 into the mold 8. Then, mass balance equation when the upper surface level of the molten metal in Kakeseki 9 rises by Δh _C (t) in the short time Δt is of the formula _{A C Δh C (t) =} {q (t) -q G (t )} Δt (7).
Furthermore, by setting Δt → 0, the change in the upper surface position of the molten metal in the hanging weir 8 is expressed by the equation (8).

Similarly, the change in the upper surface level of the molten metal in the mold 8 is expressed by Equation (9).

When the mold 8 as shown in FIG. 5 is considered, regarding the outflow flow rate q _G (t) to the mold 8, the upper surface level model of the molten metal in the mold 8 is cast down and pushed up with the weir part as a boundary. It is necessary to divide into two cases of casting. Using the Bernoulli equation and the continuous equation, the flow rate q _Gdown (t) in the case of drop casting and the flow rate Q _Gup (t) in the case of push-up casting are _obtained .
Equations (10) and (11) are obtained.
Here, c is a flow coefficient, and g is a gravitational acceleration.

Finally, by substituting Equation (10) into Equation (8) and Equation (9), respectively, the upper surface level h _C of the molten metal in the hanging weir 9 and the upper surface of the molten metal in the mold 8 in the case of drop casting. model expression level _{h m} is the formula (12), obtained with the formula (13).
Similarly, by substituting Equation (11) into Equation (8) and Equation (9), respectively, a model of the upper surface level of the molten metal in the hanging weir 9 and the upper surface level of the molten metal in the mold 2 in the case of push-up casting. Expressions are obtained as Expression (14) and Expression (15).

The parameter identified here is the flow coefficient c. The flow coefficient represents the efficiency of the flow when the molten metal flows from the hanging weir 9 through the runner and is filled into the mold 8. When the flow coefficient is 1, the inflow flow rate from the hanging weir 9 to the runner is equal to the outflow flow rate of the weir, and there is no flow loss. However, in reality, the flow coefficient does not become 1, there is some loss, and the flow coefficient is generally about 0.2 to 0.8.

Finally, the model from the input voltage u (t) to the AC servomotor 2 of the T-axis to the upper surface level h _C (t) of the molten metal in the hanging weir 9 is The model P _m (s) from the input voltage to the tilt angle of the sector ladle 1 and the flow rate model P _f (s) of the equation (6), the molten metal in the hanging weir 9 obtained from the equations (13) and (14) The model P _h (s) of the upper surface level of the above, and further, the equation P (s) = P _m (s) according to the ^dead time e ^−Td required for the molten metal to reach the hanging weir 9 from the pouring hole of the sector ladle 1 P _f (s) P _h (s) e ^−Td
It is expressed as (16).

When the target mold is a drop casting method or a push-up casting method, only the respective models need be applied. On the other hand, as shown in FIG. 5, when the mold 8 is a middle casting method, a total process model can be obtained by switching between the drop casting model and the push-up casting model.

On the other hand, the molten metal work for filling the molten metal in the sector ladle 1 into the mold 8 can be efficiently performed by calculating in advance the molten metal flow rate curve for each batch. Therefore, in the control system 7, by applying the derived upper surface level model of the molten metal, the upper surface of the molten metal in the hanging weir 9 is raised to the target level as quickly as possible, and the molten metal is started up. The method of deriving the input of the tilting of the sector ladle 1 that can maintain the position substantially constant and perform hot water cutting after pouring an arbitrary molten metal is adopted.

As for the flow rate of the rising portion of the pouring, in order to avoid giving a sudden input change to the AC servo motor 2, as shown in FIG. 6 and the equations (17) to (19), 2 with different amplitudes and cycles. Two sine waves are combined.

The following considerations are necessary for determining the amplitude and period of these sine waves.
(1) The flow rate is an equilibrium flow rate at the end of pouring of the pouring.
(2) The upper surface level of the molten metal is a target level at the end of pouring of the molten metal.
(3) At the start of pouring, the upper surface level of the equilibrium molten metal is not exceeded.

Next, the mold 8 in the equilibrium state portion in which the amount of molten metal flowing out from the sector ladle 1 and the amount of molten metal flowing into the mold 8 are made substantially equal and the upper surface position of the molten metal in the hanging weir 9 is maintained almost constant. The outflow flow rate q (t) is obtained.
Here, the mold 8 handled in the present example has a large pushed-up portion and a dominant volume compared to the drop-in portion, and the simulation results when the middle casting and the pushing casting are almost the same. Since the result is shown, the equilibrium flow rate q (t) of the molten metal is derived in consideration of only the push-up portion that is easy to calculate. That is, the flow rate q (t) when the equilibrium molten metal upper surface level h _C (t) = h _ref is obtained from the equation (14).

Finally, the control input relating to the tilting of the sector ladle 1 toward the hanging weir 2 side is derived by substituting the above-described flow rate curve into the inverse model of the equations (1) and (6). FIG. 7 shows a control simulation result in which the sector ladle 1 tilt input considering the obtained upper surface level of the molten metal is applied to the upper surface level model of the molten metal of Equation (16). In the figure, the input voltage, the fan ladle 1 tilt angle, the pouring flow rate, and the upper surface level of the molten metal in the hanging weir 2 are shown.

As a result, an ideal pouring flow curve as shown in FIG. 2 is obtained, and after the upper surface level of the molten metal in the hanging weir 2 quickly rises to the target level, the upper surface level of the molten metal is kept constant at the target level. You can confirm that it is done.

Incidentally, as described above, when the upper surface of the molten metal in the hanging weir 2 fluctuates due to some disturbance, a two-degree-of-freedom control system is used. A block diagram of the two-degree-of-freedom control system in the control system 7 is as shown in FIG.

In FIG. 8, u _ff feed Ford input, u _fb is the feedback control input, a reference input to the target top level h _ref of the molten metal in Kakeseki 9, and outputs the upper surface level hc of the molten metal in Kakeseki 9 To do. A loop shaping method, which is a general method of _H∞ control theory, was applied to the feedback control system.

The loop shaping method is a design method in the frequency domain, and is a method of determining the controller so that the frequency characteristics of the closed loop control system become the frequency characteristics desired by the designer.

Normally, as shown in FIG. 8, the switch is opened, that is, Fieldford control is performed, but when it is determined that there is a disturbance, the switch is closed and the control system is changed to the two-degree-of-freedom control system.
In the control system 7, the expression | h _c (t) −h _ref |> h _e (t ≧ t ₂ )
When the condition indicated by (21) is satisfied, a switching signal σ ₁ is sent.
Here, h _e is the tolerance of the upper surface level of the melt with respect to the target level of the molten metal.

A system diagram used when designing feedback control by the above-described loop shaping method is as shown in FIG.
Here, W _i (s) and W _o (s) are weight functions, P (s) is an object to be controlled, and K _∞ (s) corresponds to W _i (s) P (s) W _o (s). _H∞ control. The actual control is as shown in FIG.
K (s) = − W _o (s) K _∞ (s) W _i (s).
At the time of design, the dead time portion of Equation (16) is expressed as Equation (22) as a secondary Padé approximation.

Regarding the weight design, W _i (s) increases the gain in the low frequency band for improvement of sensitivity characteristics, and W _o (s) decreases the gain in the high frequency band for noise removal and higher mode reduction. In addition, the plant P (s) is weighted. Then, K (s) of the _H∞ controller that satisfies Expression (23) is designed.

Further, in the control system 7, when the sector ladle 1 is tilted to the counter dam side 8, in order to apply the hybrid shaping method on the tilt axis of the sector ladle 1, a feedback control system as shown in FIG. 10 is applied. . Thereby, the feedback of the vibration of the upper surface of the molten metal is not performed, and the positioning control can be performed at high speed without causing the vibration of the upper surface of the molten metal only by the feedback control with respect to the position of the drive system of the tilt shaft of the sector ladle 1.
Here, the control object P _m (s) indicates the drive system expressed by the equation (1),
K (s) is a controller for driving the sector ladle 1.

Thus, after pouring hot water by tilting the sector ladle 1 to the hanging weir 9 side, hot water cutting is performed by tilting the sector ladle 1 to the counter hanging weir 9 side.
In this case, the switching timing of the tilting from the side of the hanging weir 9 to the side of the hanging weir 9 according to the sector ladle 1 is changed to the weight information of the molten metal in the hanging weir 9 and the side of the hanging ladle 9 of the sector ladle 1 This is performed by predictive control for predicting the amount of follow-up outflow of the molten metal from the sector ladle 1 on the basis of the tilt angle information toward the center.

That is, the molten metal weight in the sector ladle 1 from the load cell and the sector ladle 1 from the encoder attached to the AC servo motor 2 for driving the sector ladle so as to pour the molten metal without excess or deficiency with respect to the target filling amount of the molten metal. Based on the information on the tilt angle, the amount of the trailing flow that is the weight of the molten metal flowing out from the sector ladle 1 from the start of the hot water cutting to the end of the hot water cutting is predicted, and the weight of the molten metal finally poured is controlled by the control system 7 Has predictive control.

As shown in FIG. 11, the amount of follow-up flow is divided into two parts: a molten metal in the sector ladle 1 and a molten metal in the upper part and a molten metal in the lower part, and the weight M of the molten metal in the sector ladle 1 is an over-the product weight M ₁ which is the weight of the top of the molten metal, the sum of the equilibrium weight M ₂ is the weight of the bottom of the molten metal. If the tilting of the sector ladle 1 is stopped in the state shown in FIG. 11, the overload weight M ₁ decreases, and finally the molten metal in the sector ladle 1 becomes only the equilibrium weight M ₂ .

The decrease in the overload weight M ₁ at this time has a first-order lag relationship as shown in Expression (6) between the angular velocity ω [rad / s] and the flow rate q [m ³ / s].
Here, since the angular velocity ω is 0 [rad / s], it is considered that the overload weight at this time fluctuates as in the equation M ₁ (t) = M ₁ (t ₀ ) e− ^αt (27).
Considering in discrete time, Equation (27) can be expressed as Equation M ₁ [k + j] = C _d1 A _d1 ^j x _d1 [k] (28).
Here, A _d1 and C _d1 are discrete time state equation parameters obtained from the flow rate model, and A ₁ = e ^−αt , C ₁ = 1, and x _d1 [k] = M ₁ [k].

This hot water cutting is not actually performed with the sector ladle 1 stopped, but is performed by tilting the sector ladle 1 to the counter weir 2 side. Since the pouring gate of the pan 1 rises quickly, it is considered that the amount of follow-up flow decreases. In this case, it is considered that the follow-up flow amount does not satisfy Qp = M ₁ but satisfies Qp <M ₁ . That is, when the center of tilting toward the counter weir 2 is set to the vicinity of the center of gravity of the sector ladle 1, the pouring gate of the sector ladle 1 rises and the equilibrium weight increases as shown in FIG. Since this equilibrium weight can be calculated from the tilt angle of the sector ladle 1, the locus of the tilt angle θ of the sector ladle 1 from the start of hot water cutting is predicted, and the equilibrium weight is calculated from the value.

The sector ladle 1 tilted by the control by the hybrid shaping method described above represents a closed loop system G _cl from the target value r to the output y (= tilt angle θ of the sector ladle 1) in FIG. The discrete equation of this system is expressed as follows: x _d2 [k + 1] = A _d2 x _d2 [k] + B _d2 u _d2 [k]
(30) and the equation θ [k] = C _d2 x _d2 [k] (31).

From the equations (30) and (31), θ [k + 1] can be expressed by the equation θ [k + 1] = C _d2 x _d2 [k + 1] = C _d2 (A _d2 x _d2 [k] + B _d2 u _d2 [k]) (32 )
Finally, the locus θ [k + j] at the time of tilting toward the counter weir 9 becomes as shown in Expression (33).

Increase of the equilibrium weight fraction _M 2 [k + j] is to determine by multiplying trajectories of tilting of the counter Kakeseki 9 side θ [k + j] and the flow rate gain 1000 K _f, can be expressed as Equation (34).

Finally, M ₁ (t) and M ₂ (t) can be expressed as Expression (28) and Expression (34), respectively, and considering the decrease in overload weight and the increase in equilibrium weight together, It becomes like 13.
Here, the weight of the molten metal located above the tip of the pouring spout of the sector ladle 1 that is tilting toward the counter weir 9 is the difference between M ₁ (t) and M ₂ (t). Given that these differences are equal at time t _n, after the time t _n, be subjected to further tilting of the counter Kakeseki 9 side, the molten metal will not flow out. Therefore, the predicted amount Q _p (t _o ) of the trailing flow until the time t _n shown in the following formula is Q _p (t _o ) = M ₁ (t _o ) −M ₂ (t _o ) (35) It becomes.

From these results, when the condition of Q _ref (t _o ) = Q _p (t _o ) + M (t _o ) is satisfied, the switching signal σ ₂ is sent, and the hot water cutting is started from the state where the upper surface level of the molten metal is controlled. Switch to operation.
Here, M (t _o ) is the total weight that has flowed out until time t _o , and Q _ref is the target pouring amount.

For reference, the result of a series of pouring control by the control system 7 is shown in FIG.
From the top in the figure, the control input, the tilt angle of the sector ladle 1, the upper surface level of the molten metal in the hanging weir 9,
The amount of pouring is shown, the solid line shows the result of the hot water cutting by predicting the follow-up flow amount, and the broken line is the result of starting the hot water cutting when the amount of pouring reaches the target amount.

In the above embodiment, the hanging weir 9 is manufactured separately from the mold 8 and installed on the mold 8. Of course.

It is a schematic diagram which shows one Example of the automatic pouring apparatus to which this invention is applied. It is a graph which shows the flow rate curve of the pouring by the controller system to which this invention is applied, and the relationship figure which shows the relationship between tilting of a ladle and the amount of molten metal in a hanging weir. It is a block diagram of a control system to which supervisory control is applied. It is explanatory drawing explaining the change of the pouring spout tip by tilting of a sector ladle. It is explanatory drawing explaining the relationship between the amount of molten metal in a sector ladle, a hanging dam, and a casting_mold | template in a pouring process. It is a graph shown about the flow rate curve of a molten metal, and the upper surface level of a molten metal. It is a graph which shows the simulation result by feedforward control. It is a block diagram which shows the structure of 2 free control system. It is a block diagram which shows the structure of a loop shaping method. It is a block diagram which shows the structure of the feedback control used for one Example of this invention. In the molten metal in the sector ladle is an explanatory diagram showing the relationship between excessive product weight M ₁ and the balanced weight M _2. Is an explanatory view showing a tilt change in the equilibrium weight M ₂ of the fan ladle the melt due to the counter-hooking weir side of the form ladle. In the molten metal in the sector ladle is a graph showing the relationship between time course of over-the product weight M ₁ and the balanced weight M _2. It is a graph which shows the control result of pouring in the state where disturbance does not exist in order to show the effectiveness of the present invention.

Claims (3)

The ladle is tilted by a servo motor controlled by a computer that pre-stores a program using a control system using the model method and applying supervisory control to perform the pouring process, and the molten metal from the hanging weir A method of controlling automatic pouring from the ladle to the hanging weir to avoid overflow and insufficient flow of molten metal injected into the mold,
The ladle of molten metal entering is tilted to the hanging dam side up pouring and injecting the molten metal so as to increase quickly the upper surface to the extent that the molten metal does not overflow from the Kakeseki to a target level, Notes A feed-forward control system is adopted in the process of starting up the hot water and maintaining the top surface position of the molten metal in the hanging weir almost constant, and the ladle is moved to the opposite side of the hanging weir after the start of pouring. The time until tilting is controlled by a two-degree-of-freedom control system in which a feedback control system is added to the feedforward control system, and the amount of molten metal flowing out of the ladle at the end of the pouring of the molten metal and the mold are controlled. The ladle is continuously tilted toward the hanging weir so as to inject the molten metal into the hanging weir so that the amount of molten metal flowing in is substantially equal and the upper surface position of the molten metal in the hanging weir is maintained substantially constant. , engaged in the ladle The timing of switching the tilt from the tilt to the hanging weir side to the counter-hanging weir side is based on the weight information of the molten metal in the hanging weir and the tilt angle information of the ladle toward the hanging weir side. It is determined by predicting the amount of molten metal that will be poured after the molten metal from the ladle and predicting and controlling the weight of the molten metal that is finally poured, and then controlling the tilting of the ladle toward the counterweed weir by the hybrid shaping method. Then , the molten metal in the ladle does not cause sloshing, and the ladle is tilted to the opposite side of the hanging weir to cut the hot water and finish pouring. In the automatic pouring control method according to claim 1 ,
An automatic pouring control method using a ladle having a fan-shaped longitudinal section and supported so as to be tiltable at the center of gravity. The ladle is tilted by a servo motor controlled by a computer that pre-stores a program using a control system using the model method and applying supervisory control , and the molten metal overflows from the hanging weir and is poured into the mold. A storage medium storing a control program for controlling automatic pouring from the ladle to the hanging weir to avoid a shortage of molten metal flow,
The ladle of molten metal entering is tilted to the hanging dam side up pouring and injecting the molten metal so as to increase quickly the upper surface to the extent that the molten metal does not overflow from the Kakeseki to a target level, Notes A feed-forward control system is adopted in the process of starting up the hot water and maintaining the top surface position of the molten metal in the hanging weir almost constant, and the ladle is moved to the opposite side of the hanging weir after the start of pouring. The time until tilting is controlled by a two-degree-of-freedom control system in which a feedback control system is added to the feedforward control system, and the amount of molten metal flowing out of the ladle at the end of the pouring of the molten metal and the mold are controlled. The ladle is continuously tilted toward the hanging weir so as to inject the molten metal into the hanging weir so that the amount of molten metal flowing in is substantially equal and the upper surface position of the molten metal in the hanging weir is maintained substantially constant. , engaged in the ladle The timing of switching the tilt from the tilt to the hanging weir side to the counter-hanging weir side is based on the weight information of the molten metal in the hanging weir and the tilt angle information of the ladle toward the hanging weir side. It is determined by predicting the amount of molten metal that will be poured after the molten metal from the ladle and predicting and controlling the weight of the molten metal that is finally poured, and then controlling the tilting of the ladle toward the counterweed weir by the hybrid shaping method. Then , the ladle tilting control program ends the pouring by tilting the ladle to the opposite side of the hanging weir so that the molten metal in the ladle does not cause sloshing. A storage medium that stores