JPS62138728A - Control method for raw material supply - Google Patents

Abstract

PURPOSE:To estimate the time when a scaled quantity integral value reaches a target value by sampling scaled values of a scaling hopper, applying a method of the least squares to them and finding a straight line for predicting the scaled quantity integral value, and further finding the throw-in speed of a raw material. CONSTITUTION:The raw material is stored in the scaling hopper 1 and taken out to a throw-in feeder 2 by a specific amount at each time. The raw material is further supplied to a specific raw material receiver 4 through a belt conveyor 3. At this time, the quantity of variation in the scaling hopper 1 is detected by an attached scaled quantity sensor, whose detected value is sampled by a data processor at the specific intervals of time and stored. The method of the least squares is applied while the quantity of the raw material thrown in through the feeder 2 is denoted as xi and the scaled quantity integral value measured by sampling is denoted as yi, thereby obtaining the prediction curve of the scaled quantity integral value. Then, the throw-in speed of the raw material is found from the sampled data. The quantity of thrown-in material for a throw-in target is controlled precisely based on those values.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling the supply of raw materials supplied via an input feeder from a weighing hopper having a weighing sensor and capable of weighing raw materials.

[Conventional technology]

Conventionally, this type of control method generally involves setting a target raw material input value and stopping the feeder when this target value is reached.

[Problem that the invention seeks to solve]

However, with this method, there is a problem that depending on the state of the raw material in the weighing hopper, the weighing sensor may not be able to accurately weigh the raw material, and therefore the raw material cannot be fed according to the target value.

Therefore, it is an object of the present invention to provide a control method that can accurately control the amount of raw material input.

[Means for solving problems]

By sampling the weighing value in the weighing hopper at regular intervals, applying the least squares method to this sampling data to find a straight line that predicts the cumulative weighing value, and then finding the feed speed of the raw material from this straight line, the cumulative weighing value can be calculated. Estimate the time when will reach its target value.

[Effect]

The above operations are performed when the integrated value of the scale ffi reaches a value smaller than the target value by a predetermined amount, and the time taken to reach the target value based on this point is calculated and used as the timing for stopping the input feeder. This allows the input amount to be controlled with high precision.

〔Example〕

FIG. 1 is a configuration diagram showing an embodiment of this invention, FIG. 2 is a schematic diagram showing a raw material supply system to which this invention is applied, and FIG.
The figure is a graph showing sampled weight integrated values, and is used to explain how to obtain a predicted straight line.

The operation will be explained below with reference to these figures.

The raw material is stored in a weighing hopper 1 as shown in FIG. 2, and a predetermined amount of raw material is taken out via an input feeder 2.

The extracted raw material is further supplied to a predetermined raw material receiver 4 via a belt conveyor 3 or the like.

At this time, the amount of change in the weighing hopper 1 is determined by the attached weighing sensor (
(not shown), and the detected value is sampled at predetermined time intervals (T) by a data processing device (not shown) and stored (see FIG. 1). FIG. 6 shows an example of the relationship between the sampling time t and the weighing integrated value W at this time.

By the way, the 61st constant i of a measuring instrument whose input-output relationship is a helical shape is
About iX n human power X11X2+...xn
and the reading of the measuring device Y1+)'2+・
...Calibration line y =' a x + b from yn
Considering the case where we determine the sum of the squares of the residual using the least squares method, J-, Σ(y・−(a・+b))2 ・・・・・・
(1) Define a constant a + b as shown in the following equation to minimize I-111, and...
...(2) (However, X=-;, King, x,, y = ,, g, y
From a and b obtained in this way, we can calculate the regression line y, y
It is generally known that it can be determined as -ax+b.

Therefore, considering the amount fed through the feeder as Xi, and considering the integrated weight value actually measured by springing as Yi, and applying the least squares method as described above, the third
A predicted curve of the weighing integrated value as shown by F in the figure can be obtained. Note that this curve F can be expressed as w=At+B using time t and integrated weighing value W (if expressed, the constant can be thought of as representing the slope of the straight line F, that is, the input amount iV). .

Note that B represents the intercept on the W axis.

In this way, the raw material input speed V is determined from the sampled data in the step shown in (■) in FIG.

This raises the question of where to proceed with sampling, and in this embodiment, for example, K is determined as follows.

First, set a value WK that is somewhat smaller than the target input amount WT, and set the time when the integrated value W of the weight value change reaches WT as tK (see Figure 1 ■), and use this tK as the starting point. The first sampling time after tK is set to 1n-, and sampling ends here. Then, at the sampling end point 1n-1, the feeding speed V immediately before the feeding is stopped (at the time of 1-1n-1) is calculated from the sampling data stored up to that point using the above-mentioned least squares method. In addition, the difference ΔW to the target input amount immediately before the input stop (at the time of t-jn), ΔW W TW , -1...(3)(
However, town is the target input amount, and Wn-1 is the integrated value of the change in the weighed value at the end of sampling. ), 1n-, →
The time ΔtT until reaching tT is Δ1T−1T−1n−.

becomes. Here, the total dead time of the control system is Δt.

Considering this, the timing ΔtT of the input feeder stop command starting from tn-1 is as follows. This determines the stop timing of the input feeder, and the input n can be accurately controlled with respect to the input target value.

〔Effect of the invention〕

According to this invention, even if the condition of the object to be weighed (raw material) in the weighing hopper is unstable and the weight value measured by the weighing sensor cannot be expected to be reliable, it is possible to statistically process each integrated weight value. Accurate weighing becomes possible, resulting in the advantage of highly accurate dosing control.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing an embodiment of the invention, and FIG.
The figure is a schematic diagram showing the raw material supply system, and FIG. 3 is a graph showing the transition of sampled weighed integrated values. Code explanation 1... Weighing hopper, 2... Input feeder, 3... Belt conveyor, 4... Raw material receiver, F... Prediction Straight line, 7. ~wn-11wT
・Cumulative music/weighing value. Agent Patent Attorney Akio Namiki Agent Patent Attorney Kiyota Matsuzaki Figure 1 Figure 2

Claims (1)

[Scope of Claims] In a raw material supply system that supplies raw materials from a weighing hopper capable of weighing raw materials via an input feeder, the integrated weighing value of the raw materials sequentially supplied from the weighing hopper is calculated at predetermined intervals until a predetermined time. The input speed of the raw material is estimated by performing a calculation based on the least squares method from each sampling data obtained up to the predetermined time, and the time when the integrated weighing value is predicted to reach the target value based on the input speed. A raw material supply control method characterized by estimating the time and stopping the supply of raw materials at the estimated time.