JP2001100846A - Quantitative feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably feed articles at an almost fixed flow rate, without being affected by disturbance. SOLUTION: Concerning the quantitative feeder, with which a real-time control part 8 calculates a control signal MV on the basis of a set flow rate SV preset so as to make the feeding flow rate of articles from the feeder substantially constant and a real measured flow rate PV and the feeder is controlled by this control signal, the feeder is provided with a weighting part for measuring the weight of the articles fed by the feeder for every lapse of prescribed time, a control method switching part 7 for discriminating whether a fluctuation quantity in the weight of fed articles measured by the weighting part is larger than a reference fluctuation value, and constant output holding control part 9 for controlling the feeder corresponding to the control signal calculated by the real-time control part 8 while using the fed weight provided before the fed weight, for which it is discriminated the fluctuation quantity is more than the reference fluctuation value, when it is discriminated the fluctuation quantity of the fed weight is more than the reference fluctuation value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed quantity supply device for supplying articles while maintaining a flow rate substantially constant.

[0002]

2. Description of the Related Art Conventionally, the above-described fixed-quantity supply apparatus includes a storage tank for storing articles such as powder and fluid, a supply apparatus for cutting out and supplying articles from the storage tank, and an article actually cut out from the storage tank. And a control signal MV based on a preset set flow rate SV, a proportional constant P, an integral constant I, and a supply weight W from the weighing unit. And a calculation control unit that supplies the data to the drive unit of the supply device. The flow rate refers to the weight of articles supplied per unit time by the supply device. This quantitative supply device is provided with an actual flow rate (measured flow rate) PV
Is cut out from the storage tank so that is substantially constant value (set flow rate) SV. Therefore, the control signal MV generated by the arithmetic and control unit is

[0003]

(Equation 1)

[0004] Here, e is the deviation (SV-PV). This PV is a measured flow rate, which is obtained by dividing the supply weight W of the article actually cut out from the storage tank by the operating time T _K of the drive unit. The measurement flow rate PV is calculated and calculated by the calculation control unit. And ∫e
dt is an integrated value obtained by integrating the deviation e calculated every predetermined minute time over a preset integration time I. Note that the deviation e may be a moving average value of a predetermined number of deviations.

Next, the actual measured flow rate (the flow rate of the article actually cut out from the supply device) P
The fact that V can be controlled to be the set flow rate SV will be described. Now, assuming that the actual measured flow rate PV is obtained by multiplying the control signal MV by the flow coefficient K _F , the measured flow rate PV is

[0006]

(Equation 2)

[0007] Here, K _F is a value determined by the supply device. Here, in equation (2), K _F ×
Ignoring (1 / I) × ∫edt,

[0008]

(Equation 3)

## EQU1 ## Therefore, the proportionality constant P is as follows: P = K _F × 100 × SV / PV (4) Since the set flow rate SV and the measured flow rate PV are to be made equal, the proportionality constant P may be set as P = K _F × 100 (5).

However, it is very difficult to set the proportionality constant P so as to exactly satisfy the equation (5). That is, when it is the volume flow rate that is controlled by the control signal MV, the measured flow rate PV is constant even if the set flow rate SV is constant due to fluctuation of the bulk density of the article, stability of the driving unit, and other disturbance factors. It is not stable. Therefore, equation (1) calculates the deviation e between SV and PV, and corrects the control signal MV according to the increase or decrease of the deviation e. In the equation (1), since e> 0 when SV> PV, the control signal MV is increased so as to increase the measured flow rate PV, and the reverse is performed when SV <PV. In this way, feedback is provided in the direction to cancel the deviation e, and control is performed so that the measured flow rate PV becomes the set flow rate SV even when disturbance or the like occurs.

[0011]

However, in the conventional fixed-amount supply apparatus, the control signal MV is obtained by substituting the deviation e between the set flow rate SV and the measured flow rate PV into the equation (1). However, even if the disturbance occurs and the deviation e increases for a moment, the drive unit is controlled by the control signal MV obtained based on the abnormal deviation e. In such a case, even after the disturbance disappears, It may take a certain time until the control signal MV is stabilized due to the influence of the disturbance, and it may not be possible to supply the article at the set flow rate SV in a stable state.

The conventional quantitative supply apparatus calculates the measured flow rate PV by dividing the supply weight W of the article actually cut out from the storage tank by the operating time T _K of the drive unit, and uses the measured flow rate PV. Although the control signal MV is calculated by the equation (1), when the set flow rate SV is small, the supply weight W of the articles cut out from the supply device during the preset operation time T _K (for example, 200 ms). Is lightweight, and the supply weight W may be smaller than the resolution of the measuring section. As described above, even if the drive unit of the supply device is controlled by the control signal MV calculated using the supply weight W smaller than the resolution of the measuring unit, the supply flow rate of the articles by the supply device is kept within the allowable range. There is a problem that can not be.

Further, for example, when the set flow rate SV is small, and thus the control signal MV has a very small value, a period in which the driving unit of the supply device is stopped and no articles are supplied may occur. As described above, when a period during which no article is supplied occurs, for example, when the article is sequentially supplied to a plurality of products by a predetermined weight and blended, there is a problem that a product to which the article is not supplied occurs.

[0014] The present invention provides a quantitative supply device capable of stably supplying articles at a substantially constant flow rate without being affected by disturbances (disturbances that disappear in a short time), and articles even when a set flow rate is small. It is an object of the present invention to provide a quantitative supply device capable of supplying a constant flow rate stably without interruption.

[0015]

According to a first aspect of the present invention, an article is supplied by a supply unit, and the flow rate is substantially constant.
A first control unit calculates a control signal based on a preset set flow rate and an actual measured flow rate obtained by measurement, and the fixed flow rate control device that controls the supply unit based on the control signal. In order to calculate the weighing unit that weighs the supply weight of the article actually supplied by the supply unit every time a predetermined time elapses, and the amount of change in the supply weight of the article weighed by the weighing unit is set in advance. A fluctuation amount determination unit that determines whether or not the reference fluctuation value is greater than or equal to,
When the variation amount determination unit determines that the variation amount of the supply weight of the article is equal to or greater than the reference variation value, the variation amount is obtained before the supply weight determined to be greater than or equal to the reference variation value. And a second control unit for controlling the supply unit by a control signal calculated by the first control unit using the supplied weight.

According to a second aspect of the present invention, an article is supplied by a supply unit, and the article is supplied based on a deviation between a preset set flow rate and an actual measured flow rate obtained by measurement so that the flow rate becomes substantially constant. The control unit calculates a control signal, and in the quantitative supply device that controls the supply unit based on the control signal, the supply weight of the article actually supplied by the supply unit is determined in order to calculate the measurement flow rate. A measuring section for measuring each time, a flow determining section for determining whether or not the set flow rate is equal to or higher than a preset reference flow rate, and a flow rate when the set flow rate is less than the reference flow rate When the determination unit makes a determination, a cumulative value of the deviations that is heavier than the resolution of the weighing unit is calculated, a control signal is calculated based on the cumulative value, and the supply unit is controlled by the control signal. Third system It is characterized in that it comprises a part, a.

According to a third aspect of the present invention, the article is supplied by the supply unit, and the first flow rate is set based on a preset flow rate and an actual measured flow rate obtained by measurement so that the flow rate becomes substantially constant. The control unit calculates a control signal, in the quantitative supply device that controls the supply unit by the control signal, a control signal determination unit that determines whether the control signal is equal to or less than a preset lower limit signal, When the control signal determination unit determines that the control signal is less than or equal to the lower limit signal,
A fourth control unit that controls the supply unit based on the lower limit signal.

In a fourth aspect based on the first, second, or third aspect, the first controller calculates a control signal based on the set flow rate, the measured flow rate, and the integration constant. A variation width determining unit that determines whether the variation width of the control signal is equal to or greater than a preset upper limit width and whether the variation width is equal to or less than a lower limit width; When the width is determined to be equal to or greater than the upper limit width, the integration constant is changed to be increased, and when the variation width of the control signal is determined to be equal to or less than the lower limit width, the integration constant is decreased. And an integration constant changing unit that changes
It is characterized by having.

According to the present invention, the first control unit calculates a control signal based on the set flow rate and the measured flow rate, and can control the supply unit based on the control signal. According to the first aspect, when the fluctuation amount determination unit determines that the fluctuation amount of the supply weight of the article obtained by the measuring unit every time the predetermined time elapses is equal to or more than the reference fluctuation value, the fluctuation amount is changed to the reference fluctuation time. The second control unit can control the supply unit by the control signal calculated by the first control unit using the supply weight obtained before the supply weight determined to be equal to or more than the value.

According to the second aspect, when the flow rate determination section determines that the set flow rate is equal to or higher than the reference flow rate, the first control section calculates a control signal based on a deviation between the set flow rate and the measured flow rate. The supply unit can be controlled by the control signal. However, when the flow rate determination unit determines that the set flow rate is less than the reference flow rate, the third control unit calculates the cumulative value of the deviations of the number that is heavier than the resolution of the measuring unit, and based on the cumulative value. A control signal is calculated, and the supply unit can be controlled by the control signal.

According to the third aspect, when the control signal determination section determines that the control signal exceeds the lower limit signal, the first control section calculates the control signal based on the set flow rate and the measured flow rate. The supply unit can be controlled by the control signal. However, when the control signal determination unit determines that the control signal is equal to or less than the lower limit signal, the fourth control unit can control the supply unit based on the lower limit signal.

According to the fourth aspect of the present invention, the variation width determining unit determines whether the variation width of the control signal is equal to or greater than the upper limit width and whether the variation width is equal to or less than the lower limit width. Change the integration constant to be larger when the fluctuation range of the signal is determined to be equal to or larger than the upper limit width, and to decrease the integration constant when the fluctuation range of the control signal is determined to be equal to or smaller than the lower limit width. Can be changed.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a quantitative supply device according to the present invention will be described with reference to the drawings. As shown in FIG. 2, the quantitative supply device includes a storage tank 1, a supply device 2, a driving unit 3 thereof, and a measuring unit 4. Since these are the same as those described as the conventional fixed-quantity supply device, detailed description will be omitted. The analog weighing signal from the weighing unit 4 is
Is converted into digital weight signals W _D by the A / D converter 5,
It is input to the arithmetic and control unit 6 which is a microcomputer. The arithmetic control unit 6 outputs the digital weighing signal (weight) W
Calculation is performed based on _D and the set flow rate SV per unit time, and a control signal MV is supplied to the supply device 2. The arithmetic control unit 6 can control the drive unit 3 of the supply device 2 by the control signal MV. The weighing section 4 sequentially calculates (every 200 ms) the weight of the articles in the storage tank 1 and sequentially calculates (every 200 ms) the weight W of the articles cut out by the supply device 2 and outputs the calculated weight W. is there. Then, the arithmetic control unit 6 calculates the control signal MV every 200 ms and supplies the control signal MV to the supply device 2.

Next, the actual measured flow rate P per unit time
Control performed by the arithmetic and control unit 6 so that V becomes the set flow rate SV per set unit time will be described. As shown in FIG. 1, the arithmetic control unit 6 includes a control method switching unit 7, a real-time control unit 8, and a fluctuation range determination unit (S206, S21).
0), an integration constant changing unit (S208, S212), a constant output holding control unit 9, a first limiter control unit 10, and a second limiter control unit 11. Each control unit such as the control method switching unit 7 and the real-time control unit 8 is configured to perform predetermined arithmetic processing according to a predetermined program stored in a storage unit (not shown).

The control method switching section 7 includes a fluctuation amount determining section, a flow rate determining section, and a control signal determining section. The variation determining unit corresponds to step S102 shown in FIG. 3, and the variation in the weight of the article in the storage tank 1 measured by the measuring unit 4 (the article supplied by the supply device 2 based on the variation). Is calculated to be greater than or equal to a preset reference variation value.
If the weight of the article in the storage tank 1 fluctuates by 1% or more of the weight of the weighing section 4 within 0.4 seconds (within a predetermined time), the fluctuation amount of the weight of the article is changed to the reference fluctuation value. If not, it is determined that the amount of change in the weight of the article is less than the reference change value. 0.4 seconds of this predetermined time and 1% of the weighing are preset, and 1% of the weighing is set.
% Is the reference variation value. For example, when the floor vibration that disappears in a relatively short time is transmitted to the weighing unit 4 and the floor vibration component is mixed in the weighing signal indicating the weight of the article in the storage tank 1 measured by the weighing unit 4, In addition, this is for detecting the floor vibration component.

The flow rate judging section corresponds to step S106, and the set flow rate SV is set to a preset reference flow rate S
It is determined whether or not the voltage is _{equal to} or higher than VK. Control signal determination unit corresponds to step S308, in which the control signal MV to determine whether it is less than the lower limit signal MV _L which is set in advance.

According to the control method switching section 7, in step S102, the fluctuation amount of the weight of the article in the storage tank 1 is equal to or larger than the reference fluctuation value within 0.4 seconds (within a predetermined time), and the fluctuation amount determination section determines YES. If it is determined that the first
Switch 12 is switched to a position where the switch 12 is connected to the first limiter control unit 10. In this case, the arithmetic control unit 6 controls the supply device 2 by the first limiter control unit 10. Then, in step S102, the fluctuation amount of the weight of the article in the storage tank 1 is less than the reference fluctuation value in 0.4 seconds, and the fluctuation amount determination unit determines NO, and in step S106, the set flow rate SV is changed to the reference flow rate SV _K. And the flow rate determination unit is Y
It determines that ES, further, in step S308, when the control signal MV is the control signal judging unit has exceeded the lower limit signal MV _L is determined NO, and a position for connecting the first switch 12 to the real-time control unit 8 By switching, the second switch 13 is switched to a position where the second switch 13 is connected to the output terminal 14. In this case, the arithmetic control unit 6 includes the real-time control unit 8
To control the supply device 2. Step S10
In 2, the fluctuation amount of the weight of the article in the storage tank 1 is less than the reference fluctuation value in 0.4 seconds, and the fluctuation amount determination unit determines NO, and in step S106, the set flow rate SV is equal to or more than the reference flow rate SV _K. flow determining unit determines YES, and further, in step S308, when the control signal MV is the control signal judging unit is equal to or less than the lower limit signal MV _L is determined YES, and connecting the first switch 12 to the real-time control unit 8 The second switch 13 is switched to a position where the second switch 13 is connected to the second limiter controller 11 in a state where the second limiter control unit 11 is connected to the second switch 13. In this case, the arithmetic control unit 6 controls the supply device 2 by the second limiter control unit 11 while performing the control by the real-time control unit 8.

Further, in step S102, the storage tank 1
The fluctuation amount of the weight of the article in the area is less than the reference fluctuation value in 0.4 seconds, and the fluctuation amount determination unit determines NO, and the step S106
In the case where a set flow rate SV is determined as a reference flow rate SV is less than _K the flow determination unit is NO, Further, in step S308, the control signal MV is the control signal judging unit has exceeded the lower limit signal MV _L is determined as NO Is the first switch 1
2 is switched to a position to be connected to the constant output holding control unit 9,
The second switch 13 is switched to a position where the second switch 13 is connected to the output terminal 14. In this case, the arithmetic control unit 6 performs the processing of the supply device 2 by the constant output holding control unit 9. Then, in step S102, the fluctuation amount of the weight of the article in the storage tank 1 is less than the reference fluctuation value in 0.4 seconds, and
And judgment, at step S106, the set flow rate SV is less than the reference flow rate SV _K rate determining unit determines NO, and
Further, in step S308, when the control signal MV is the control signal judging unit is equal to or less than the lower limit signal MV _L is determined YES, and in a state switched to a position connecting the first switch 12 to the constant output holding control section 9 Then, the second switch 13 is switched to a position where the second switch 13 is connected to the second limiter control unit 11. In this case, the arithmetic control unit 6 controls the supply device 2 by the second limiter control unit 11 while the control by the constant output holding control unit 9 is being performed.

Real-time controller 8 (first controller)
Is equivalent to that of a conventional metering device.
The actual flow rate (measurement flow rate)
Volume) PV so that it is substantially constant value (set flow rate) SV.
In step S200 shown in FIG. 4, control is performed by calculating equation (1).
The signal MV is generated. Note that the deviation e (= SV
-PV) is an example obtained by calculating every 200 ms, for example.
For example, a moving average value of eight deviations e 'is used. Fluctuation range
The determination unit determines that the fluctuation width R of the control signal MV is set in advance.
Upper limit width R_UIt is determined whether or not it is the above (S206), and
And lower limit width R_LIt is determined whether or not it is below (S210).
Things. The integration constant changing unit uses a variation width determining unit to
The fluctuation width R of the control signal MV is the upper limit width R _UJudge as above
So that the integration constant I in equation (1) is increased.
Is changed (S208), and the fluctuation width R of the control signal MV becomes the lower limit width.
R_LWhen it is determined that the following, the integration constant of the equation (1)
I is changed so as to be smaller (S21
2).

The configuration of the real-time control unit 8, the fluctuation range determination unit, and the integration constant changing unit and the arithmetic control performed by them will be described more specifically with reference to the flowchart shown in FIG. 4 and FIG. FIG. 6 shows the behavior of the control signal MV in an appropriate control state by the real-time control unit 8. The set flow rate SV is constant, and the control signal MV fluctuates with a certain fluctuation width R substantially vertically symmetrically with respect to the average value.
Now, _assuming that the time is t _n , the real-time control unit 8 _sets the sample values MV _t0 , MV _t1 ,..., MV _tn of the control signal at the time (time) t _n and each time before it as (1). It is calculated by the formula and stored in the storage unit (S20
0). Then, the operation time of the supply device 2 is T _S (= t
_n− t ₀ ) It is determined whether the time has elapsed (S202).
If the time T _S has elapsed and the determination is YES, the T
The average value MV _H of the control signals MV _{t0 to} MV _tn within the _S time and the fluctuation range R are calculated and stored (S204). Fluctuation width R
Is a control signal M calculated in each of predetermined sections in a period from time t _{0 to} t _n.
Variations in V width R _1, R _2, ····, an R _m. Then, among the fluctuation ranges R ₁ , R ₂ ,..., R _m , a fluctuation width R of 10% or more (upper limit width R _U ) or more of the maximum control width of the control signal occurs continuously three times or more. And the fluctuation width determining unit determines whether or not the control signals MV _{t0 to} MV _tn fluctuate with a periodicity (S206). If the determination is YES, the integration constant changing unit determines (1) )) To increase the integration constant I (S208). The degree to which the integration constant I is increased is set to increase by one second when the integration constant I is, for example, 10 seconds. The determination as to whether or not the control signals MV _{t0 to} MV _tn fluctuate with a periodicity is performed by a conventionally known method using the average value MV _H , though not described in detail.

However, if NO is determined in step S206, all of the fluctuation widths R ₁ , R ₂ ,..., R _m are, for example, 1% or less (lower limit width R _L ) of the maximum control width of the control signal. Is determined by the fluctuation range determination unit (S2).
10) When the determination is YES, the integration constant changing unit decreases the integration constant I of the equation (1) (S212). The degree to which the integration constant I is reduced is such that the integration constant I is reduced by one second when the integration constant I is, for example, 10 seconds. And
In step S206, when the time T _S has not elapsed and the determination is NO, and when the variation width R exceeds the lower limit width _RL and the determination is NO in step S210, the integration constant I is not changed. Next, the control signal MV is calculated using the original I (S200).

[0032] Thus, the integration constant change section, since the fluctuation width R of the control signal MV is modified to increase the integral constant I when it is determined that the upper limit width R _U above, the control signal MV By making the fluctuation width R small, the fluctuation width R of the supply flow rate PV can be kept within an allowable range. Then, when it is determined that the fluctuation width R of the control signal MV is equal to or smaller than the lower limit width _RL , the response of the control signal MV can be made faster by changing the integration constant I so as to be smaller. For example, even if the measured flow rate PV fluctuates greatly for some reason, control can be performed so as to quickly approach the set flow rate SV.

The first limiter control unit 10 (second control unit) determines the fluctuation amount when the fluctuation amount of the weight of the article cut out (supplied) by the supply device 2 is equal to or larger than the reference fluctuation value. When the unit determines (S102), for example, the real-time control unit 8 uses the weight obtained before the weight determined to have the amount of change in the weight of the article equal to or more than the reference change value to calculate the weight. The supply device 2 is controlled by the control signal MV (S104). The first limiter control unit 10 corresponds to step S104 in FIG.

Next, control by the first limiter control unit 10 will be described. FIG. 7 shows that the supply weight W of the article supplied from the supply device 2 during a predetermined time (200 ms) is measured every predetermined time (200 ms) in a state where the supply device 2 is controlled by the real-time control unit 8. It is a figure showing the data obtained. In FIG. 7, until the time t _h , the fluctuation amount determination unit (S1) shown in FIGS.
02), the flow rate determination unit (S106), and the control signal determination unit (S308) make the determination. As a result, the real-time control unit 8 (S200 to S212) illustrated in FIG. Suppose you are controlling. Here, when, for example, floor vibration occurs at time t _i and the vibration component mixes with the weighing signal of the weighing unit 4, the supply weight W of the article calculated by the weighing unit 4 fluctuates rapidly. In step S102 shown in the figure, since the fluctuation amount determination unit determines whether the fluctuation amount of the supply weight W of the article is equal to or larger than the reference fluctuation value, it is determined that this vibration component is mixed in the weighing signal of the weighing unit 4. Can be detected. Then, the fluctuation amount of the supply weight W is equal to or more than the reference fluctuation value, and the fluctuation amount determination unit
If it is determined that the ES detects a vibration component, the first limiter controller 10, using the supply weight W _h obtained before the supply weight W _i that is determined variation amount is equal to the reference variation value or more it is possible to control the supply device 2 by the control signal MV _h calculated by the real-time control unit 8 and (S
104). Thus, since the control signal MV is not calculated using the abnormal supply weight W including the vibration component generated due to the vibration of the floor or the like, the supply of the article can be performed without changing the control signal MV in the wrong direction. The flow rate (measured flow rate) can be controlled stably.

Next, at time t _j , when the fluctuation amount of the supply weight W _j is less than the reference fluctuation value, and the fluctuation amount determining section determines NO and detects that the vibration component has disappeared, the first
The control by the limiter control unit 10 can be stopped, and the control by another control unit such as the real-time control unit 8 can be performed. In step S100, deviation e = SV (set flow rate) -PV (measured flow rate) is calculated. The deviation e is used when the real-time controller 8 calculates the equation (1) (S200) and when the constant output holding controller 9 calculates the accumulated value E (S300).

The constant output holding control unit 9 (third control unit)
When setting the flow rate SV is a flow rate determining section is less than the reference flow rate SV _K is determined (S106), calculates a cumulative value E of the deviation e of the heavier becomes number than the resolution of the measuring portion 4 (= SV-PV) The control signal MV is calculated based on the accumulated value E, and the supply device 2 is controlled by the control signal MV (S300 to S306 shown in FIG. 5). That is, when the control is performed by the real-time control unit 8, the supply device 2 is controlled within the predetermined time every predetermined time (200 ms).
The supply weight W of the article cut out from the product is calculated and calculated by the measuring unit 4, and the supply weight W is determined for a predetermined time (200 ms).
And the control flow MV is calculated by the equation (1) using the measured flow rate PV. However, when the set flow rate SV is less than the reference flow rate SV _K , the supply weight W may be smaller than the resolution of the measuring unit 4, and the measured flow rate PV may be reduced using the supply weight W smaller than the resolution of the measuring unit 4. Even if the calculated flow rate PV is calculated and the control signal MV is calculated to control the supply device 2, the supply flow rate of the article may not be within the allowable range. Therefore, the total value E of the deviations e (= SV−PV) of the number that is heavier than the resolution of the weighing unit 4 is calculated, the control signal MV is calculated based on the total value E, and the supply device is calculated based on the control signal MV. 2 is to be controlled. Thereby, the supply flow rate of the article can be kept within the allowable range. If the time interval for calculating the deviation e is a first time (T ₁ = 200 ms), a second time (T ₂ = for example, one minute) longer than the first time elapses. Each time, 300 (= 6) calculated within this second time
0 second / 200 ms).

The control by the constant output holding control unit 9 is shown in FIG.
It will be described in the light of the above. Past predetermined time T_TwoCalculated within
Is accumulated (S300). And when
Interval T _TwoIt is determined whether or not has elapsed (S302).
T_TwoHas elapsed and when the determination is YES, the new control
Signal MV₁, MV₁= MV₀−K × E (6) (S304). And calculate this
Obtained new control signal MV ₁Controls the supply device 2
U. MV₀Is the current control signal, K is the coefficient, E is the bias
This is a cumulative value of the difference e. However, in step S302
And time T_TwoHas not elapsed and the determination is NO,
The cumulative value E of the deviation has not been calculated and the new control signal MV₁
Cannot be calculated, the current control signal MV₀Powered by
The device 2 is controlled (S306).

FIG. 8 is a diagram showing a state in which the current control signal MV ₀ has been changed to a new control signal MV ₁ by the constant output holding control unit 9. MV _Z is a control signal corresponding to the set flow rate SV. As can be seen from FIG. 8, the new control signal M
The V ₁ does not match the MV _Z once, so that close to MV _Z after several changes. The reason is to prevent the control from going too far. Therefore, the coefficient K is set to 1
It is set to a smaller value.

The second limiter control unit 11 (fourth control
) Is the lower limit signal M for which the control signal MV is set in advance.
V_LWhen the control signal determination unit determines that
Limit signal MV_LControls the supply device 2.
That is, in step S308 shown in FIG.
Signal MV is lower limit signal MV _LControl signal judgment
And the control signal MV is set to the lower limit signal MV._LBelow
If the answer is YES, the second limiter control unit 11
Is the lower limit signal MV _LTo control the supply device 2 (S31)
0). However, in step S308, the control signal M
V is the lower limit signal MV_LIs exceeded and the result is NO
Is controlled by another control unit such as the real-time control unit 8.
Can be Thereby, the real-time control unit 8 and the like
Supply device 2 by the fluctuation of the control signal MV calculated by
Stop and there is a period during which no goods are supplied
Can be reliably prevented.

According to the quantitative supply apparatus configured as described above, as shown in the flow charts of FIGS. 3 to 5, the supply is usually performed by the real-time control unit 8 using the control signal MV calculated by the equation (1). The control of the device 2 is performed.
When a disturbance such as a floor vibration (disturbance that disappears after a short time elapses) is transmitted to the controller and a large error is mixed in the supply weight W (S102), the first limiter controller 10 does not perform the real-time control. Control is performed (S104). When the set flow rate SV is equal to or higher than the reference flow rate SV _K (S106), the real-time control unit 8 (S200 to S2)
12) Or the supply device 2 is controlled by the second limiter control unit 11 (S310). When the set flow rate SV is less than the reference flow rate SV _K , the constant output holding control unit 9 (S
300 to S306) or the second limiter control unit 11 (S
The supply device 2 is controlled according to 310). Further, when the control signal MV is below the lower limit signal MV _L controls the supply device 2 by the second limiter control section 11 (S310). As described above, since the control unit suitable for controlling the supply device 2 is selected from a plurality of control units and used in accordance with the various situations described above, the set flow rate SV, Alternatively, the articles can be supplied at a constant flow rate close thereto.

However, in the above embodiment, the weight (flow rate) of the articles cut out from the storage tank 1 per unit time (flow rate) is calculated by measuring the weight of the articles in the storage tank 1 by the measuring unit 4. Although an example in which the present invention is applied to the (in weight type) quantitative feeder is shown, the weight of an article passing on a weighing conveyor is weighed by the weighing unit 4 in another form, for example, and is sent out by the weighing conveyor. The present invention is applicable to a fixed-quantity supply device that calculates the flow rate of articles. In the above embodiment, the real-time control unit 8 calculates the control signal MV by calculating the equation (1). Instead, the MV may be calculated using another calculation equation. For example,

[0042]

(Equation 4)

The following equation can be used.

[0044]

According to the first aspect of the invention, for example, the vibration of the floor (vibration that disappears in a relatively short time) is transmitted to the weighing section, so that the fluctuation amount of the supply weight of the articles measured by the weighing section is changed by the reference fluctuation. If the fluctuation amount judgment unit determines that the abnormal load has been applied to the weighing unit, it is not necessary to use the abnormal supply weight, but to use the appropriate supply weight obtained earlier. The second control unit can control the supply unit by the control signal calculated by the first control unit. As described above, since the control signal is not calculated using the abnormal supply weight including the vibration component generated due to the vibration of the floor, the supply flow rate of the article ( There is an effect that the measurement flow rate can be stabilized and controlled.

According to the second aspect, when the flow rate determination section determines that the set flow rate is less than the reference flow rate, the total number of deviations of a number which is heavier than the resolution of the measuring section is calculated, and this total value is calculated. The supply unit can be controlled using the control signal calculated based on the control signal. Thereby, the supply flow rate (measurement flow rate) of the article by the supply unit can be supplied relatively stably within the allowable range.

According to the third aspect, when the control signal determination section determines that the control signal is equal to or less than the lower limit signal, the fourth control section controls the supply section based on the lower limit signal. Thus, it is possible to reliably prevent the supply unit from stopping due to the fluctuation of the control signal calculated by the first control unit and causing a period during which no articles are supplied. Thus, for example, when the article is sequentially supplied to a plurality of products at a predetermined weight and blended, it is possible to reliably prevent the occurrence of a product to which the article is not supplied.

According to the fourth aspect, the integration constant changing unit includes:
When it is determined that the fluctuation width of the control signal is equal to or larger than the upper limit width, the integration constant is changed so as to increase, so that the fluctuation width of the control signal can be reduced to keep the fluctuation width of the supply flow rate within an allowable range. it can. Then, when it is determined that the fluctuation width of the control signal is equal to or less than the lower limit width, the integration constant is changed to be smaller, and the response of the control signal can be made faster, thereby, for example, changing the set flow rate. Then, the supply flow rate can be brought close to the set flow rate in a short time.

[Brief description of the drawings]

FIG. 1 is a block diagram showing details of arithmetic control provided in a quantitative supply device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a fixed quantity supply device according to the embodiment.

FIG. 3 is a flowchart showing the content of controlling the supply device by the fixed-quantity supply device according to the embodiment.

FIG. 4 is a flowchart showing the content of controlling the supply device by the fixed-quantity supply device according to the embodiment.

FIG. 5 is a flowchart showing the content of controlling the supply device by the fixed-quantity supply device according to the embodiment.

FIG. 6 is a diagram showing a behavior of the control signal MV in an appropriate control state by the real-time control unit of the embodiment.

FIG. 7 is a diagram showing a change in weight of an article supplied by the supply device of the embodiment.

8 is a diagram showing a state in which to change the current control signal MV ₀ new control signal MV ₁ by the constant output holding control unit of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Storage tank 2 Supply device 4 Measuring part 6 Operation control part 7 Control method switching part 8 Real-time control part 9 Constant output holding control part 10 First limiter control part 11 Second limiter control part

Claims (4)

[Claims] An article is supplied by a supply section, and a first control section controls the article based on a preset set flow rate and an actual measured flow rate obtained by measurement so that the flow rate becomes substantially constant. In a quantitative supply device that calculates a signal and controls the supply unit with the control signal, in order to calculate the measured flow rate, the supply weight of the article actually supplied by the supply unit is changed every time a predetermined time elapses. A weighing unit for weighing, a variation determining unit that determines whether a variation in the supply weight of the article measured by the measurement unit is equal to or greater than a preset reference variation value, and When the variation amount determination unit determines that the variation amount is equal to or greater than the reference variation value, a supply weight obtained before the supply weight determined that the variation amount is equal to or greater than the reference variation value is used. The first control unit Dispensing apparatus characterized by comprising a second control unit for controlling the supply unit by the issued control signal. 2. An article is supplied by a supply section, and a first control section is provided based on a deviation between a preset set flow rate and an actual measured flow rate obtained by measurement so that the flow rate is substantially constant. Calculates a control signal and controls the supply unit based on the control signal. In order to calculate the measured flow rate, the supply weight of the article actually supplied by the supply unit elapses a predetermined time. A weighing unit that measures each time, a flow rate determination unit that determines whether the set flow rate is equal to or greater than a preset reference flow rate, and the flow rate determination unit determines that the set flow rate is less than the reference flow rate Then, a third control for calculating a cumulative value of the deviations of a number that is heavier than the resolution of the weighing unit, calculating a control signal based on the cumulative value, and controlling the supply unit with the control signal. Parts and Dispensing device which is characterized in that. 3. The article is supplied by a supply section, and the first control section controls the flow based on a preset flow rate and an actual measured flow rate obtained by measurement so that the flow rate is substantially constant. In a quantitative supply device that calculates a signal and controls the supply unit with the control signal, a control signal determination unit that determines whether the control signal is equal to or less than a preset lower limit signal, and the control signal When the control signal determination unit determines that the supply signal is equal to or less than the lower limit signal, the fourth control unit controls the supply unit based on the lower limit signal.
And a control unit. 4. The quantitative supply device according to claim 1, wherein the first control unit calculates a control signal based on the set flow rate, the measured flow rate, and an integration constant, and performs the control. A fluctuation width determination unit that determines whether the fluctuation width of the signal is equal to or larger than a predetermined upper limit width and whether the fluctuation width is equal to or smaller than the lower limit width, and the fluctuation width determination unit determines a fluctuation width of the control signal. Is changed so as to increase the integration constant when it is determined to be equal to or greater than the upper limit width, and to decrease the integration constant when the variation width of the control signal is determined to be equal to or less than the lower limit width. And an integration constant changing unit for changing the constant supply.