JPH04118527A - Weighing device - Google Patents

Abstract

PURPOSE:To punctually complete weighing at a prescribed time by controlling an article supply quantity so as to conform a weighing value through a weighing part with a memorized time series target value of weighing. CONSTITUTION:Information of a weighing value of a weighing part 2 is converted to a digital quantity with a A/D convertor 62 and input to a control means 4, a final weighing target value set with a setting part 63 and a time series target value of weighing from the beginning time of weighing memorized by a memory means 5 to the final weighing target value are also input to the control means 4. The control means 4 outputs a control signal to control opening degree of the opening/closing gate 13 of a supply part 1 based on respective input information. This control signal is a digital quantity corresponding to the opening degree, after converting to analogue voltage, it is input to a servo driver 65. The driver 65 drives a servo motor 14 to adjust the opening degree of the gate 13 of the supply part 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a weighing device used for weighing articles such as powder and granules to a target needle depth.

[Conventional technology]

Such a measuring device includes a supply section that supplies articles in a variable supply amount, a measuring section that stores the articles supplied in the supply section and measures the stored amount, and a final A control means for controlling the supply section so as to reduce the amount of articles supplied as it approaches a target measurement value is used.

The reason why the supply unit is controlled to reduce the article supply amount as the measured value by the measurement unit approaches the final measurement target value is that the smaller the article supply amount is, the smaller the article supply amount will be, the less the measurement accuracy will be adversely affected. This is because the influence of vibrations and the like during the supply of articles can be reduced, and more accurate weighing can be achieved.

In such a weighing device, the state of article supply by the supply section (for example, the state of the article supply by the supply section (for example,
The amount of supply of the article was adjusted accordingly.

[Invention or problem to be solved]

In the case of such a conventional weighing device, as described above, the article supply amount is reduced when the weighed value approaches the final weighing target value, thereby achieving accurate weighing. However, since the supply amount has been adjusted by controlling the state of the article supply according to the deviation between the measured value by the measuring section and the final measurement target value, the state of the article supply is , changes depending on the condition of the article in the supply section (for example, the amount of articles accumulated in the supply section, the accumulation distribution, etc.), and due to the change, the amount of article supplied also changes, and as a result, the time required for weighing becomes uncertain. There was a problem.

The present invention was made in view of such circumstances, and
The purpose is to solve the conventional problem of not being able to determine the measuring time, and to provide a measuring device that can perform measurements as accurately as the conventional method.

[Means to solve the problem]

The measuring device according to the present invention includes a supply section that supplies articles in a variable supply amount, a measuring section that stores the articles supplied in the supply section and measures the stored amount, and a final measurement value of the measured value by the measuring section. and a control means for controlling the supply unit to reduce the supply amount as it approaches the target measurement value, and a first characteristic configuration thereof is that the final target measurement value is maintained from the start of measurement. Storage means is provided for storing time-series measurement target values up to
The present invention is configured to control the amount of articles supplied by the supply unit so that the measurement value by the unit matches the time-series measurement target value stored in the storage means.

A second characteristic configuration is that a storage means is provided for storing time-series measurement target values from the middle of measurement to the final measurement target value, and from the middle of measurement, the control means The present invention is configured to control the amount of articles supplied by the supply unit so that the measurement value by the unit matches the time-series measurement target value stored in the storage means.

A third characteristic configuration is that in the first and second characteristic configurations, the control means controls the supply of the article by fuzzy reasoning based on the deviation between the measured value and the measured target value and the amount of change in the deviation. in that it is configured to control the amount.

[For production]

According to the first characteristic configuration, the article supply amount is controlled so that the measured value by the measuring unit matches the time-series measured target value stored in the storage means, so that after a predetermined period of time has elapsed, If the above-mentioned control is performed by setting the measurement target value as the final measurement target value, the measurement will be completed within the predetermined time.

In addition, by appropriately determining the time-series measurement target value as described above (for example, reducing the amount of goods supplied as it approaches the final measurement target value), accurate measurement can be performed on a par with conventional weighing devices. .

According to the second characteristic configuration, while supplying a large amount of articles to the weighing section until the middle of weighing to shorten the supply time,
From the middle of measurement, when the measurement time is relatively likely to vary, it is possible to carry out measurement for a fixed period of time in the same manner as in the case of the first characteristic configuration.

According to the third characteristic configuration, the control of the article supply amount in the first and second characteristic configurations is performed by using a deviation between the measured value and the measured target value and a change amount of the deviation as input variables. This is done based on the amount of operation determined by Soi inference.

〔Effect of the invention〕

The first characteristic structure solves the conventional problem of not being able to determine the measuring time, and provides a weighing device that is capable of measuring as accurately as the conventional weighing device even though it does not perform fixed-time weighing.

The second characteristic configuration is that by using a combination of large-volume supply in a short period of time up to mid-measurement and fixed-time metering from mid-measurement to completion of measurement, measurement can be performed quickly and with less fluctuation in measurement time. It has become possible.

According to the third characteristic configuration, by applying fuzzy reasoning to the control for the above-mentioned fixed-time weighing, it is possible to relatively easily realize control that is not affected by the characteristics, condition, and disturbances of the article to be weighed. I was able to do something.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the measuring device of the present invention, in which (1) is a supply section that supplies the article (A) in a variable supply amount, and (2) is the supply section ( This is a measuring section that temporarily stores the article (A) supplied in step 1) and measures the stored amount.

Specifically, the supply section (1) includes an article storage hopper (12) equipped with a supply cylinder (11) with an open bottom end at the bottom;
An opening/closing gate (13) provided at the lower end opening of the supply cylinder (11) is provided. The opening/closing case) (13) is
The pivot point (13a) is connected to the output shaft of the reducer (15) which is connected to the servo motor (14).
), and the degree of opening of the lower end opening of the supply tube (11) is adjusted in accordance with the drive.

Specifically, the No. 111 measuring section (2) is the supply section (1).
) A hopper-shaped cylinder with an opening at the bottom (2N)
The opening at the lower end is equipped with a discharge gate (22) which can be opened or closed.

Then, the article (A) supplied from the supply section (1) is temporarily stored in the hopper-shaped cylinder (21) with the discharge cage (22) closed, and the stored amount is measured. It is now possible to do this. Specifically, the measurement means are:
The hopper-shaped cylinder (21) is attached to the support portion of the cylinder (21).
The hopper-shaped cylinder (2) storing the article (A) is loaded using a load cell (23) arranged so that
1) The method of measuring the weight is adopted.

The measurement value information (analog voltage) obtained by the measurement section (2) is amplified by an amplifier (61) and sent to an A/D converter (
After being converted into a digital quantity at step 62), it is inputted as a measured value to the control means (4). The control means also controls the final measurement target value set in the setting section (63) and the time-series measurement target value from the start of measurement to the final measurement target value stored in the storage means (5). (4) is input.

The control means (4) is equipped with a microcomputer, and outputs a control signal for controlling the degree of opening of the opening/closing cage (13) of the supply section (1) based on the above-mentioned human power information. The second control signal is a digital quantity corresponding to the opening degree, and after being converted into an analog voltage by a D/A converter (64), it is input to the servo driver (65). Then, the servo driver (65) drives the servo motor (14) according to the analog voltage, thereby causing the supply section (1
) Adjust the opening degree of the opening/closing gate (13).

The information regarding the time-series measurement target values stored in the storage means (5) is as shown in FIG. 2, for example. In FIG. 2, the horizontal axis represents time t, and the vertical axis represents the measurement target value W, indicating the measurement start time t. It shows the time-series measurement target value at the measurement completion time tel from 1 to the final measurement target value We. In this example, the measurement start time t. After some time has elapsed, start increasing the target measurement value,
Initially, the slope in Table 1 (corresponding to ΔW/Δt in the figure) is set to be large for the amount of goods supplied per unit time, and as time passes, the slope is decreased, and when the final weighing target value is reached, the slope is The measurement target value is changed steplessly so that it becomes zero. In reality, a simplified line graph consisting of a plurality of inclination forces may be used. In other words, it is sufficient to store four tables of metric target values for the time at the turning point of multiple liability in the storage means (5).

The control means (4) performs measurement at regular intervals.

The amount of goods supplied by the supply unit (1) is controlled so that the measured value sampled by (2) follows the time-series graph of 5-quantity target value stored in the storage means (5). do. That is, the measurement target value W at any sampling timing ti from the start of total 1 to the completion of measurement
The opening degree of the opening/closing gate (131) of the supply section (1) is controlled so that the deviation between the measured value ω and the measured value ω is zero.

Specifically, based on the deviation and its variation ΔD, the opening degree, that is, the D/A converter (64
) determines the digital amount to be output.

Description will be given below according to the control block diagram shown in FIG. 3 and the flow chart shown in FIG.

As mentioned above, the control means (4) includes the storage means (5).
From then, the measurement target value W corresponding to the time from the start of measurement is
Also, a measured value ω is input from the measuring section (2) via an amplifier (61) and an A/D converter (62). As shown in FIG. 3, from these two input information, the deviation calculating section (4I) first calculates the deviation D=W-ω, and then the deviation change amount calculating section (42) calculates the deviation change amount ΔD. =D-Dp (however, D
p is the previous value of the deviation) is calculated. The results of these calculations and ΔD are then given to the fuzzy controller (43) as input variables. Fuzzy controller (43
) includes a rule storage unit (44) that stores a plurality of rules (control rules) to be described later, and a fuzzy inference unit (45) that applies the input variables and ΔD to these rules to obtain an output result (operated amount V). ). As described above, the operation amount V is a digital amount corresponding to the degree of opening of the opening/closing gate (13) of the supply section (1).

In this way, the control means (4) controls the degree of opening of the opening/closing gate (13) so that it matches the measured value sampled at regular intervals or the measured target value stored in the storage means (5). , this control is repeated until the final weighing target value We is obtained (see FIG. 4). Then, when the final weighing target value We is obtained, the weighing is completed, and after that, the discharge gate (22) is opened and the article (A) is discharged into another container or the like (not shown).

Next, the fuzzy controller (43) will be explained. The rule storage section of the fuzzy controller (43) (
The rules stored in 44) are expressed as follows, for example.

IF D=PB AND ΔD=NTHEN
V=NS The above-mentioned input deviation calculation section (41) and deviation change amount calculation section (
42) is a single quantity, whereas D and ΔD that describe this rule are fuzzy variables expressed by membership functions. Similarly, ■ is also a fuzzy variable here.

Further, symbols such as PB, N, and NS are labels of possible values of the respective fuzzy variables. For reference, if we describe the above rule in words, if deviation (D) or positive magnitude (P
If B) and the amount of change (ΔD) is negative (N), set the manipulated variable (V) to a negative small (NS).

bawl. This means that if the measured value is larger than the total target value and the deviation is changing in the direction of decreasing, D
This means that the output to the /A converter (64) is set to a small negative value, the servo motor (I4) is slightly reversed, and the opening degree of the opening/closing gate (13) is slightly narrowed.

For all rules, the relationship between the input variables and ΔD of the antecedent part and the operation NV of the consequent part can be expressed as 1,1 x as shown in Table 1.

Although the explanation of the membership function of each fuzzy variable in the first table will be omitted, as can be seen from the first table, D is represented by five labels and ΔD is represented by three labels.

Depending on these combinations, 15 rules are defined, and the value of the manipulated variable V of the consequent of each rule is 5.
represented by labels.

Fuzzy inference part (45) of fuzzy controller (43)
) applies the input scale and ΔD value from the deviation calculation unit (41) and deviation change amount (42) to each of the above rules,
The manipulated variable V of the consequent part is determined from the degree of fitness. The MAX-MIN method is used as the inference method at this time. Then, the final single manipulated variable V is determined by integrating the manipulated variables (2) determined by each rule. The centroid method is used for this calculation. The above-mentioned MAX-MIN method and centroid method are well known as general fuzzy inference methods in fuzzy control, so their explanation will be omitted here.

In the above manner, the fuzzy controller (43)
The operation amount V corresponding to the adjustment amount of the opening degree of the opening/closing cage (13) of the supply section (1) is determined from the deviation between the measurement target value and the measurement value and the amount of change ΔD. This manipulated variable or V is converted into an analog voltage by the D/A converter (64) as described above, and then input to the servo driver (65). Then, depending on the analog voltage, the surf motor (14)
The opening/closing gate (13) of the supply section (1) is driven by
The degree of opening is adjusted.

[Another example]

In the fuzzy inference of the above embodiment, only the deviation between the metric target value and the metric value and the amount of change △D thereof were used as input variables, but other conditions may be added to the input variables to perform more fine-grained control. Conceivable. For example, a setting means may be provided to set the ease of flow of the article (powder, granules, etc.) to be measured depending on the type of the article, and the set value may be added to the input variables. Note that the rules and inference methods for fuzzy inference shown in the embodiments are not limited to these, and can be modified in various ways.

Further, in the embodiment, when a plurality of final measurement target values are set in the setting section (63), a plurality of time-series measurement target values corresponding to the plurality of final measurement target values are stored in the storage means (63).
Although it may be necessary to store all of the information in step 5), another method is to express the measurement target value as a function with the final measurement target value We as a parameter and time t as a variable, and store this function in the storage means (5). It is also conceivable to memorize the following and calculate time-series metric target values one by one according to the set final metric target value.

Further, the information stored in the storage section is set as a time-series measurement target value from the middle of measurement to the final target value, and the opening degree of the supply section is increased until the middle of measurement. It is also possible to consider an embodiment in which a large quantity of articles is supplied to the supply section in a short period of time, and from the middle of the measurement, the measurement is carried out for a fixed period of time in the same manner as in the above-mentioned embodiment.

Note that the present invention is applicable not only to weight measurement as in the above-described embodiments, but also to volume measurement.

Note that although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure of the accompanying drawings by these entries.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing one embodiment of a measuring device according to the present invention, FIG. 2 is a graph showing time-series measurement target values stored in its storage means, and FIG. 3 is a control block diagram. ,
FIG. 4 is a control flow chart. (1)... Supply section, (2)... Measuring section, (4)... Control means, (5)... Memory means, (A )... Goods.

Claims (1)

[Claims] 1. A supply unit (1) that supplies the article (A) in a variable supply amount.
), a measuring section (2) that stores the article (A) supplied in the supply section (1) and measures the stored amount, and the measuring section (
2) A measuring device comprising a control means (4) for controlling the supply unit (1) so as to reduce the supply amount as the measured value approaches the final measurement target value, the metering device comprising: Storage means (5) is provided for storing time-series measurement target values from to the final measurement target value, and the control means (4) stores the measurement values from the measurement section (2) in the storage means. (5) A weighing device configured to control the amount of articles supplied by the supply section (1) so as to match the time-series measurement target value stored in (5). 2. Supply unit (1) that supplies the article (A) in a variable supply amount
), a measuring section (2) that stores the article (A) supplied in the supply section (1) and measures the stored amount, and the measuring section (
2) A measuring device comprising a control means (4) for controlling the supply unit (1) so as to reduce the supply amount as the measured value approaches the final measurement target value, during the middle of measurement. Storage means (5) is provided for storing time-series measurement target values from A weighing device configured to control the amount of articles supplied by the supply section (1) so that the weighed value matches a time-series measurement target value stored in the storage means (5). 3. Claim (4) in which the control means is configured to control the article supply amount by fuzzy reasoning based on a deviation between the measured value and the measured target value and an amount of change in the deviation. 1. The measuring device according to 1.