JPH06158125A - Method for controlling weighing of discharged raw material - Google Patents

Abstract

PURPOSE:To improve the precision of the final discharged raw material quantity and to shorten the weighing time of the raw material by obtained the target discharging velocity from a control function of discharging residual amount and the discharging velocity, and the actual discharging residual amount to control the discharging velocity. CONSTITUTION:The actual discharged raw material quantity (w) obtd. by weighing a weighing hopper 1 with a load cell 2a and corrected by a zero regulating computing element 3, is compared with the target raw material quantity W and at the time when the residual amount S becomes zero, the discharge from a stocker 13 is stopped. In this weighing control method, with a first and a second target discharging velocity computing elements 4, 7, limitor 5, high selector 6, etc., the control function F for the discharging residual amount and the discharging velocity is beforehand obtd. in the permissible range of changing velocity in the raw material discharging velocity and in the range of stable control. At the time of actually discharging the raw material, the discharging velocity U is obtd. from the weighing integrated value WL in the weighing hopper 1 and compared with the aimed discharging velocity V obtd. from the S and F. Based on this deviation, control voltage P is obtd. by a PID 9 and an SCR 10 to control a motor 11 for discharging feeder 12.

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a raw material cutting and weighing control method for weighing already cut raw materials and stopping the cutting when a target raw material amount is reached.
To provide a raw material cutting and weighing control method capable of further improving the accuracy of the finally cut raw material quantity and cutting out a desired quantity of raw material in a relatively short time without increasing various data management.

[0002]

2. Description of the Related Art Raw materials to be charged into a blast furnace, such as ore, coke, and auxiliary materials, are weighed by a load cell attached to a weighing hopper, for example, from a predetermined stocker while weighing raw materials that have already been cut out. Only the target raw material quantity is cut out. In addition, the raw material thus cut out by the target raw material amount is transported by a predetermined conveyor or the like and charged into a blast furnace. This is to stop the cutting when the target raw material amount is reached while weighing the already cut raw material (hereinafter referred to as raw material cutting weighing control). Various techniques have been disclosed for such raw material cutting and weighing control.

For example, in JP-A-48-5161, different raw materials supplied from different ore reservoirs equipped with controllable feeders are fed through a continuously running conveyor common to all ore reservoirs. Then, the actual weight value obtained by the weight measuring device is combined with the amount related to the change in weight, and the target weight value and the predetermined comparison device are used as the actual value of the sum. There is disclosed a technique relating to an automatic charging device for various raw materials into a blast furnace, in which the feeding device is stopped when the actual weight value of the sum reaches the target weight value. Said JP-A-48
-5161 is in particular the sum of the weight actual value measured by the weighing device and an additional actual value previously given in relation to the length of the conveyor and the load between the reservoir and the weighing device When the weight target value is reached, the feed rate of the feeding device can be switched from large to small. At the same time, instead of the load actual value, the quantity related to the change in weight formed from the change in weight per unit stroke and the travel distance of the raw material is
Together with the actual weight value measured by the weight measuring device, the actual value of the sum is led to the comparison device. According to the technique disclosed in JP-A-48-5161,
It is possible to reduce measurement errors when the conveyor speed of the conveyor fluctuates or when the conveyor belt on which the material of the conveyor is loaded is stopped and then moved again.

Japanese Patent Application Laid-Open No. 117422/1982 discloses a technique relating to a method of controlling the discharge of powders and granules in a step of charging powders from a plurality of bins into a hopper via a transport means such as a conveyor. there is Said JP-A-57-11742
In 2, the feeder stop timing of the feeding bin this time is determined by the set value of weighing in the hopper (W) and the intermediate weighing value in the hopper (Wo
) and the time when it was obtained (To), the feeder unloading weight speed (Fi), the length of the conveyor between the unloading bin and the hopper (L
bi) and the conveyor speed (Vb). Also, the next feeder start timing for the picking bin is calculated and determined from the W, Wo, To, Fi, Vb and the length of the conveyor between the next picking bin and the hopper. In addition, at the time when the cut-out granular material reached the weighing setting value (W) in the hopper this time and the conveyor was stopped,
This is to leave only the next cut powder or granules on the conveyor. According to JP-A-57-117422,
It is possible to obtain a constant particle property for each batch, and to stably supply a desired weight by accurate moisture measurement.

On the other hand, Japanese Patent Application Laid-Open No. 61-47535 discloses a blast furnace coke cutting and weighing apparatus having a plurality of ore storage tanks, a plurality of cutting devices provided corresponding to the respective ore storage tanks, a belt conveyor, and a weighing hopper. A technique related to a blast furnace coke cutting control device related to equipment is disclosed. The Japanese Patent Laid-Open No. 61-
In 47535, raw material loading amount calculation means for calculating the coke loading amount on the belt conveyor from the product of the cutting speed obtained from the weighing speed, the elapsed time from the start of cutting to the present time, and the current weighing value of the weighing hopper. I have. Further, the coke loading amount calculated by the raw material loading amount computing means is subtracted from the weighed remaining amount value with respect to the weighing target value, and when the result of this subtraction becomes equal to or less than a predetermined amount, a cutting stop signal is output to the cutting device. It has a cutting stop timing control means. According to JP-A-61-47535, the amount of coke of the previous batch mixed in the weighed coke is reduced, accurate moisture measurement of coke, accurate weighing of the required amount of coke and in-furnace for each batch It is possible to allow granular charging to the

[0006] FIG. 4 is a block diagram showing the configuration of a weighing control device to which a conventional raw material cutting and weighing control method is applied.

[0007] In FIG. 4, the weighing controller 80
While weighing the raw material already cut into the weighing hopper 1, the cutting speed of the raw material is controlled by the cutting feeder 12 arranged below the stocker 13 storing the raw material to be weighed. In addition, the weighing control device 80
When the target raw material quantity is reached, the cutting by the cutting feeder 12 is stopped.

[0008] In such a weighing control device 80, the amount of raw material already cut into the weighing hopper 1 is measured by the load cell 2a and the weighing calculator 2b. The output of the weighing calculator 2b is the field indicator 71 and the weighing signal A/
It is input to the D converter 70 . Also, the moisture content of the raw material already cut into the weighing hopper 1 is measured by a neutron moisture meter 60
measured in The measurement results are input to a recorder 61 that prints the values sequentially and to a moisture signal A/D converter 62 .

In the weighing control device 80 shown in FIG. 4, first, the weighing schedule device 72 obtains a weighing set value for weighing the raw materials stored in the stocker 13 this time, that is, a target raw material quantity, This is written into the weighing set value memory 74 .

[0010] On the other hand, the actual extracted raw material quantity A/D-converted by the weighing signal A/D converter 70 is processed by the actual extracted value calculator 40 and the WET/DRY converter 42 as an actual extracted quantity W _FEDi. is converted to Cumulative error value calculator 44
obtains the cumulative error value Σ ⁱ Dj from the output of the WET/DRY converter 42 . Here, the WET/DRY converter 42 obtains a dry cut amount based on the moisture content A/D-converted by the moisture signal A/D converter 62 .

Extraction target value calculator 46 and DRY/WE
The T-converter 48 obtains the cutout target value W _TGTi according to the value written in the weighing set value memory 74 and the cumulative error value Σ ⁱ Dj calculated by the cumulative error value calculator 44 . The cutting target value W _{TG Ti} takes into consideration the moisture content of the material actually cut. A value that takes into account this actual moisture content is obtained by the DRY/WET converter 48 .

[0012] The extraction stop value calculator 50 is the DRY/
The cutout target value W _TGTi obtained by the WET converter 48
Then, the extraction stop value W _ST is obtained. The comparison device 52
Determination of pre-quantitative detection, determination of quantitative detection, and determination of empty amount detection are performed mainly according to the extraction stop value W _ST . The pre-quantitation detection is a determination that the raw material being discharged to the weighing hopper 1 is approaching the target raw material quantity. The quantitative detection is a determination as to whether or not the target raw material quantity has been reached. The empty amount detection is to determine whether or not all the materials in the weighing hopper 1 that have already been weighed have been discharged.

[0013] Based on the result of such determination, the sequence control device 54 outputs an operation command or a low speed command to the clipping control circuit 56 . The operation command is transmitted from the stocker 13 to the weighing hopper 1 to the cutting feeder 1.
In 2, the raw material is cut out. The low speed instruction is to perform such extraction at low speed. The cutting control circuit 56 actually controls the cutting feeder 12 based on the operation command and the low speed command.

[0014] Further, the conventional weighing control device described above specifically performs the following calculations.

That is, first, according to the following equation, the extraction actual value calculator 40 and the WET/DRY converter 42
, W _FEDi
Ask for

_{WFEDi =} ( _W100i - _W0i )*(1-αi) (1)

Also, the accumulated error value Σ ⁱ Dj at this time can be obtained by the accumulated error value calculator 44 according to the following equation.

^ΣiDj =Σi ^- 1Dj+(WFEDi- _WSETi ) (2)

At this time point, the target extraction value W _TGTi to be further extracted is obtained by the target extraction value calculator 46 according to the following equation.

_WTGTi = _WSETi+1 - ^ΣiDj (3)

Furthermore, the cutting stop value W _ST , that is, the judgment value for stopping the cutting performed while weighing is set to the DRY/W
In the ET converter 48 and the extraction stop value calculator 50, it is obtained by the following equation.

W _STi+1 =W _oi+1 +W _TGTi+1 /(1−α _i )−W _OVF (4)

When the extraction stop value W _ST is obtained in this way, the determination of pre-quantitative detection, the determination of quantitative detection, and the determination of empty amount detection are carried out by the comparison device 52 as follows. It is done with two formulas.

_WIN ≧ _{W ST} −WL → Before quantitative determination (5a) _WIN ≧W _ST → Fixed quantity (100%) (5b) _WIN ≤ _WE → Empty amount (0%) (5c)

Various constants and variables in the above equations (1) to (5c) are as follows.

W ₁₀₀ : Full amount read value (WET value) (6a) W ₀ : Empty amount read value (WET value) (6b) W _FED : Actual output amount (DRY value) (6c) ΣDj: Accumulated error value (DRY value) …(6d) W _SET : Weighing set value (DRY value)* …(6e) _WTGT : Cutting target value (DRY value) …(6f) W _OVF : Inflow amount (WET value) …(6g) W _ST : Extraction stop value (WET value) …(6h) _{W IN} : Weighing read value (WET value) …(6i) WL : Set value before weighing (WET value)* …(6j) W _E : Empty volume set value (WET value)* … (6k) α : Moisture content … (6l)

Here, * marks are preset data.

FIG. 5 is a graph showing the cutting speed command voltage and the actual cutting speed in the conventional weighing controller.

In FIG. 5, the cutting speed command voltage E used in the cutting control circuit 56 during the control of the cutting feeder 12 and the actual cut raw material amount obtained from the weighing calculator 2b are shown. Extraction speed
A graph with v is shown. The actual extraction speed v is
It is obtained by differentiating the actual extracted raw material amount.

In the graph of FIG. 5, first, time t ₀
, the cutting speed command voltage E of the cutting control circuit 56 is approximately the rated voltage, and the cutting speed at that time is set to the maximum. After the time t ₀ , the actual cutting speed v of the raw material to be cut fluctuates due to various external factors during cutting, as indicated by the dashed line in FIG.

[0031] After that, when the amount of material that has been actually cut out is 80 to
At the point of time when it reaches 90%, that is, at time t ₁ , the comparison device 52 makes the determination of the pre-quantitation detection and outputs this to the sequence control device 54 . As a result, the sequence control device 54 and the clipping control circuit 56
The cutting speed of the raw material cut out from the stocker 13 is reduced. As a result, the starting speed command voltage E
is also reduced.

After that, when the quantitative detection is determined by the comparison device 52, the cutting of the raw material is stopped at _time t2. At this time, the cutting speed command voltage E becomes zero. Even after _time t2, the inflow amount W _OVF indicated by hatching in FIG. 5 is added. For this reason, the weighing control device 80 carries out predictive control of this inflow amount W _OVF according to past actual values. This means that cutting is stopped a little early in anticipation of the inflow amount W _OVF .

[0033]

However, the above-described conventional raw material dispensing and weighing control method has the following problems.

1. Problem of Weighing Control Accuracy: Conventional raw material extraction and weighing control has many elements of predictive control, and the accuracy of weighing control may decrease. Predictive control is to correct accumulated error values sequentially. Therefore, the error in the average value is constant over a large number of batches, but there is a tendency for the absolute weighing control accuracy per batch to deteriorate. In particular, in the case of raw materials charged into a blast furnace, control of the ratio of ore and coke in one batch is an important control index. Therefore, deterioration of weighing control accuracy in one batch becomes a problem.

2. Too much data management: The aforementioned conventional raw material cutting and weighing control has many elements of predictive control, which increases the amount of various data, resulting in a problem of data management. Accumulated error values and the like as described above need to be accumulated in a large number of batches, resulting in a complicated control configuration including data management and reset processing.

3. Weighing time becomes long: When a certain amount is cut out in order to ensure weighing control accuracy, the cutting speed is slowed down as described above, so weighing time becomes long.

4. The actual cutting speed fluctuates during weighing: As indicated by the dashed line in FIG. 5, the actual cutting speed v fluctuates even though the cutting speed command voltage E is constant. Such fluctuations are caused by the characteristics of the stocker 13 and the cutting feeder 12,
It depends on the brand and moisture content of the raw material being cut. Such fluctuations in the actual extraction speed v become a factor that deteriorates the weighing control accuracy.

[0038] The present invention has been made to solve the above-mentioned conventional problems. It is an object of the present invention to provide a raw material cutting and weighing control method capable of cutting out a predetermined amount of raw material in a short time.

[0039]

[Means for Accomplishing the Object] The present invention is a method of weighing raw materials that have already been cut out, and at the time when the target raw material quantity is reached,
In this raw material cutting and weighing control method for stopping cutting, the rate of change in the cutting speed of the raw material is within the allowable range of the cutting speed change speed of the electric motor system and the mechanical system that controls it, and the control of the cutting speed control A control function F between the remaining amount Sf to be cut and the cutting speed Vf, which is within the stable control range of the system, is obtained in advance.
The actual cutting remaining amount s and the actual cutting speed v are measured, the actual cutting remaining amount s is compared with the control function F, the target cutting speed V is obtained from the corresponding cutting speed Vf, and the actual cutting speed v is the above The object is achieved by performing closed-loop control so as to achieve the target cutting speed V and continuously controlling the actual cutting speed v.

In the raw material cutting and weighing control method, first, a control function F1 between the elapsed time Tf and the cutting speed Vf is obtained. By considering the stable control range of the control system when obtaining the control function F from the control function F1, the above object is achieved and the control function F can be obtained more efficiently. It is.

[0041]

In order to improve the accuracy of the finally cut raw material quantity and at the same time shorten the weighing time of the raw material, the present invention continuously changes the actual cutting speed v during weighing. This was accomplished by finding a more effective method that could be controlled to reduce variability.

In the present invention, first, the control function F of the cutting remaining amount Sf and the cutting speed Vf is obtained in advance. The control function F is obtained based on the weighing result of the raw material already cut out, and when the remaining amount to be cut out from this, that is, the cut out residual amount SF is obtained,
This is a function for obtaining the clipping speed Vf, which is a reference for finding the target clipping speed V for this.

Further, in the present invention, once the target cutout speed V is obtained, the actual cutout speed v is calculated by a predetermined method.
is obtained, the actual clipping speed v is continuously controlled by closed-loop control. Therefore, according to the present invention, it is possible to improve the accuracy of the amount of material finally cut out and to shorten the weighing time of the material.

Further, in the present invention, the control function F is such that the rate of change in the cutting speed of the raw material is within the allowable range of the cutting speed change speed of the electric motor system and the mechanical system that controls it, and the cutting speed The cutting remaining amount Sf and the cutting speed V are such that they are within the stable control range of the control system of control.
It is a function of f.

In raw material cutting and weighing control, for example, the cutting feeder and the electric motor for the cutting feeder, which change the cutting speed of the raw material, always have an upper limit to the response speed due to their respective limited torques. Therefore, in the present invention, focusing on this point, the rate of change in the cutting speed of the raw material is set to be within the allowable range of the cutting speed change speed of the electric motor system and the mechanical system that control this. For example, as in the examples described later, changes in the raw material cutting speed,
That is, since it is difficult to control the acceleration of the extraction speed to a predetermined value or more, the control function F as described above is obtained so that the acceleration of the extraction speed is within the allowable range.

Also, in the present invention, as described above, the remaining amount of clipping Sf is obtained first, and by using this and the control function F,
The target cutout speed V is obtained, and the actual cutout speed v
It is a combination of several control systems that perform closed-loop control of Also, each control system has its own stable control range. For example, there is a measurement error or the like when obtaining the cut-out remaining amount Sf. Also, with regard to the control function F, when a data table or the like is used, discrete errors may occur. Further, the closed loop control related to the actual cutting speed v also has a stable control range peculiar to the closed loop control. In the present invention, the control function F is obtained in consideration of such a stable control range of the control system for controlling the cutting speed.

Therefore, according to the invention, the control function F
is within the permissible range of the cutting speed change rate as described above, and is considered to be within the stable control range of the control system as described above, so the accuracy of the finally cut raw material amount is further improved. In addition to being able to
It is also possible to reduce variations in the actual cutting speed v during weighing of the raw material.

In the present invention, the control function F is not specifically limited, but the clipping speed F, which serves as a reference for obtaining the target clipping speed V as described above, according to the calculated remaining clipping amount Sf. Any function can be used as long as it can obtain Vf.

The control function F is obtained by determining the relationship between the elapsed time Tf and the clipping speed Vf, that is, the control function F1, as in the embodiment described later. You may make it consider the permissible range of speed. Further, when obtaining the control function F from the control function F1, the stable control range of the control system may be considered. In this way, by obtaining several functions in a supplementary manner, it is possible to take into account the conditions regarding the control function F as described above. Also, the obtained control function F can be easily made to have a margin in the allowable range of the rate of change of the cutting speed and the stable control range of the control system. According to the control function F with such a margin, even if there are various disturbances, it is possible to ensure the accuracy of the finally cut raw material amount, and the actual cutting speed v during raw material weighing can be increased. Variation can also be reduced.

In the present invention, the data management basically concerns only the control function F described above. For example, there is basically no need to manage performance data for each of a large number of batches, unlike in the past. In this respect, it is possible to reduce various problems in data management. However, the present invention is not limited to not using performance data relating to such a large number of batches, and various data may be stored and used as control parameters.

[0051] Further, the raw material cutting and weighing control of the present invention is not limited to being used in combination with other control methods. For example, as in the conventional example described above with reference to FIGS. 4 and 5, the water content of the raw material is measured by the neutron moisture meter 60, and when the raw material is cut out or weighed, this is done. Consideration may also be given to the moisture content measured by

[0052]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a raw material cutting and weighing control device to which the present invention is applied.

In FIG. 1, the raw material cutting and weighing control device of this embodiment weighs the already cut raw material in the weighing hopper 1, and when the target raw material amount W is reached, the material is moved from the stocker 13 to the cutting feeder 12. is to stop the segmentation performed via . The cutting feeder 12
3, the control of the actual cutting speed v during cutting and the stopping of the cutting are performed by being driven by the cutting feeder motor 11 . Further, the weighing of the already cut material in the weighing hopper 1 is carried out using a load cell 2a attached to the weighing hopper 1 and a weighing calculator 2b connected thereto. From the weighing calculator 2b, an output _wL corresponding to the amount of material already stored in the weighing hopper 1 is produced.

[0055] Such a raw material cutting and weighing controller mainly comprises a zero-normalization calculator 3, a differential calculator 8, a first target cutting speed calculator 4, a target cutting speed limiter 5, and a second target cutting speed. Speed calculator 7 and high selector 6
, adders 14a and 14b, a PID calculator 9, and a thyristor primary voltage controller 10 (hereinafter referred to as SCR 10).

Since the load cell output w _L output from the weighing computing unit 2b has a weight error due to adhered matter in the weighing hopper 1, it is corrected by the zero-normalization computing unit 3, that is, zero-calibration is performed. conduct. The zero correction is to subtract the load cell output w _L when the weighing hopper 1 is empty from the load cell output w _L during raw material unloading. Further, the differential calculator 8 is used to obtain the load cell output w _L
By differentiating , the actual extraction speed v is obtained.

The adder 14a calculates the target raw material quantity W
By subtracting the actual extracted raw material quantity w from the above, the actual extracted remaining amount s is obtained. The actual cut remaining amount s is the amount of raw material that must be further cut at that time. The actual cutout remaining amount s decreases as time elapses.

The first target clipping speed calculator 4, the target clipping speed limiter 5, the second target clipping speed calculator 7, and the high selector 6 determine the remaining clipping speed Sf and the clipping speed Vf. A control function F of is formed. In addition, these configurations collate the actual clipping remaining amount s with the control function F, and from the corresponding clipping speed Vf,
A target cutting speed V is obtained. For these configurations,
Details will be described later with reference to FIGS. 2 and 3. FIG.

The adder 14b and the PID calculator 9
and the SCR 10, the actual extraction speed v
is the target cutting speed V, a closed-loop control is performed.

The adder 14b is connected to the high selector 6
The actual clipping speed v output from the differentiation calculator 8 is subtracted from the target clipping speed V output from . Thereby, the adder 14b obtains the deviation between the target cutting speed V and the actual cutting speed v.

The PID calculator 9 calculates a PID (proportional PID) related to closed-loop control for the input deviation.
(integral and derivatine) calculation is performed, and the cutting speed command voltage E according to the deviation is obtained. The cutting speed command voltage E is proportional to the raw material cutting speed controlled by the cutting feeder 12 and the cutting feeder motor 11 .

The SCR 10 controls the cutting feeder motor 1 according to the inputted cutting speed command voltage E.
1 to control the cutting feeder motor power P supplied to 1. The SCR 10 follows the cutting speed command voltage E of the cutting feeder motor 11 and the cutting feeder 12 while measuring the operating position of the cutting feeder 12 with a pulse generator attached to the cutting feeder motor 11 . position control. In addition, the SCR10
At this time, while the rotation speed of the cutting feeder motor 11 is being detected by the pulse generator, the cutting feeder motor power P is controlled by closed-loop control of the rotation speed.

FIG. 2 is a graph showing the control functions of elapsed time and cutting speed used in this embodiment.

In FIG. 2, the control function F1 of the elapsed time Tf and the clipping speed Vf, which is used when obtaining the control function F, is indicated by a solid line. This graph shows the remaining time t until the desired target raw material quantity W is reached. The remaining time t decreases according to the elapsed time Tf. That is, the elapsed time Tf progresses from right to left in this graph. Further, as the elapsed time Tf progresses or as the remaining time t decreases, the actual cutout remaining amount s decreases.

As indicated by the solid line in the graph of FIG. 2, until the remaining time _tD , control is performed at the target cutting speed V as shown by the following equation.

V=Vm (6)

Also, until the remaining time _tD , the target clipping remaining amount S is expressed by the following equation.

S=Vm·t (7)

where Vm is the maximum cutting speed (ton/
seconds). That is, the raw material is cut out at the maximum cutting speed Vm until the remaining time _tD , thereby shortening the weighing time of the raw material. After the remaining time t _D , the target raw material amount W
Until the remaining time t becomes zero, the target extraction speed V is obtained by the following equation.

V=Km·t (8)

Km is a predetermined constant so as to prevent over-weighing when stopping the cutting when the target raw material amount W is reached. For example, the constant Km is set in consideration of the delay of the control system, the raw material remaining in the cutting feeder 12, and the like.
Further, the constant Km is set so that the acceleration of the cutting speed is within the allowable range of the limit torque of the electric motor system and the allowable range of the limit torque of the mechanical system in the remaining time _tD . In addition, in the period from the remaining time _tD until the remaining time becomes zero, the target extraction remaining amount S is expressed by the following equation.

S=(Km·t ² )/2 (9)

Eliminating the remaining time t from the above equations (8) and (9) yields the following equation.

V=(2·Km·S) ^1/2 (10)

The above equation (10) corresponds to the control function F1 between the elapsed time Tf and the clipping speed Vf. The calculation of the function of the equation (10) is performed by the first target clipping speed calculator 4 and the target clipping speed limiter 5 . That is, what is obtained by the above equation (10) and the first target clipping speed calculator 4 is the first target clipping speed V1. Also, the first target clipping speed V1 is clamped to a certain upper limit value by the target clipping speed limiter 5 . The clamp corresponds to the formulas (6) and (7). Also, the target clipping speed limiter 5 provides a first target clipping speed clamp value V3. According to the first target cutting speed clamp value V3, the raw material can be weighed in the shortest time within the allowable range of the cutting speed change speed of the electric motor system and the mechanical system.

[0076] However, in the vicinity of the target cut-out remaining amount S being zero, as shown in the following equation, the value becomes infinite, and the loop gain of the weighing control system becomes extremely high. Therefore, it is not preferable in terms of control stability.

lim _S → ₀ (Dv/Ds)→∞ (11)

Therefore, in this embodiment, when the stability limit gain of the weighing control system is k, the second target extraction speed V2 obtained by the following equation is also used.

[0079] V2=k S (12)

The calculation of the above equation (12) is performed by the second target clipping speed calculator 7 .

The high selector 6 selects the larger one of the first target clipping speed clamp value V3 and the second target clipping speed V2 and outputs it as the target clipping speed V. FIG. Such an operation of the high selector 6 is represented by the formula (10) and the formula (1).
2) Switching operation at the contact as shown by the following formula is performed.

S1=(2·Km)/k ² (13)

Note that the first target clipping speed calculator 4
, the target extraction speed limiter 5, the second target extraction speed calculator 7, and the high selector 6, the control function of the extraction remaining amount Sf and the extraction speed Vf used in this embodiment F is as shown in the graph of FIG.

In the graph of FIG. 3, (v=k.multidot.s) is obtained when the remaining cutout amount Sf is from zero to S1.
From S1 to tD, (v=( _2.Km.S ) ^1/2 ).

Above tD, (v= _Vm ).

In this embodiment, the function F
The target clipping speed V can be obtained by:
Further, in this embodiment, according to the target cutting speed V, the actual cutting speed v is controlled as described above.

Therefore, according to this embodiment, the previously cut raw material is weighed using the control function F suitable for various situations of the electric motor system, the mechanical system, and the control system. However, this clipping can be controlled. Therefore, it is possible not only to improve the accuracy of the amount of raw material finally cut out, but also to shorten the weighing time of the raw material.

In addition, fluctuations in the actual cutting speed v during weighing can be reduced. This is the actual extraction speed v
is controlled in a closed loop according to the target cutting speed V.

In this embodiment, the control function F as shown in FIG. 3 can be realized with a relatively simple configuration by using the high selector 6 or the like. That is, the function represented by the formula (10),
Switching to the function represented by the formula (12) can be performed with a relatively simple configuration.

[0090] In this embodiment, the desired control accuracy is ensured without performing predictive control as in the conventional example. However, the present invention can also be performed in combination with various predictive controls. For example, the delay time of the control system is
The cutting feeder motor 11 and the cutting feeder 1
2 operation delay and the effect of the raw material remaining in the cutting feeder 12 or the portion after it, there is a possibility that _overweighing corresponding to the inflow amount _WOVF in the conventional example may occur. In this embodiment, when the target raw material quantity W is reached and the extraction is stopped, the target extraction speed V and the actual extraction speed v are decelerated.
Such overweighing is believed to be rare. However, it is also possible to apply predictive control with the present invention to account for such overweighing.

[0091]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, it is possible to improve the accuracy of the amount of raw material finally cut out without increasing the management of various data, and to obtain the desired amount in a relatively short time. It is possible to obtain the excellent effect of being able to weigh the raw materials.

[Brief description of the drawing]

FIG. 1 is a block diagram showing the configuration of a raw material cutting and weighing control device of an embodiment to which the present invention is applied;

FIG. 2 is a graph showing a control function F1 between elapsed time Tf and cutting speed Vf used in the embodiment;

FIG. 3 is a graph showing a control function F for the cutting remaining amount Sf and the cutting speed Vf used in the embodiment;

FIG. 4 is a block diagram showing the configuration of a conventional weighing control device;

FIG. 5 is a graph showing cutting speed command voltage E and actual cutting speed v in the conventional weighing control device;

[Description of symbols]

Reference Signs List 1 Weighing hopper 2a Load cell 2b Weighing calculator 3 Zero normalization calculator 4 First target cutting speed calculator 5 First target cutting speed limiter 6 High selector 7 Second target cutting speed calculator 8 Differential calculator 9 PID calculator 10 Thyristor primary voltage controller 11 Cutting feeder electric motor 12 Cutting feeder 13 Stocker 14a, 14b Adder W Target raw material quantity (unit ton) w Actual cut raw material quantity (unit ton) w _L ... load cell output s ... actual cutting remaining amount V ... target cutting speed V1 ... first target cutting speed V2 ... second target cutting speed V3 ... first target cutting speed clamp value v ... actual cutting speed E ... Cutting speed command voltage P... Cutting feeder motor power

Claims (2)

[Claims] 1. A raw material cutting and weighing control method for weighing already cut raw materials and stopping the cutting when a target raw material amount is reached, wherein the rate of change in the raw material cutting speed controls this. A control function F of the cutting residual amount Sf and the cutting speed Vf that is within the allowable range of the cutting speed change speed of the electric motor system and the mechanical system and is within the stable control range of the control system of the cutting speed control is obtained in advance. , During the actual raw material cutting, the actual cutting remaining amount s and the actual cutting speed v are measured, the actual cutting remaining amount s is compared with the control function F, and the target cutting speed V is calculated from the corresponding cutting speed Vf. A method for controlling the weighing and weighing of raw material, characterized in that closed-loop control is performed so that the actual cutting speed v becomes the target cutting speed V, and the actual cutting speed v is continuously controlled. 2. A method according to claim 1, wherein a control function F1 for the elapsed time Tf and the clipping speed Vf is first obtained, and the control function A raw material weighing control method, wherein the stable control range of the control system is taken into consideration when obtaining the control function F from F1.