JP3021980B2 - Position tracking method for conveyed goods - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for tracking the position of a conveyed article, and more particularly, to a method for conveying a form in an optical character reading apparatus and a sheet in an automatic mail processing apparatus. The present invention relates to a method for tracking the position of a conveyed object in a case where it is required to increase the amount of conveyed object per unit time by shortening the interval and sending.

[0002]

2. Description of the Related Art In the reading performance of an optical character reading apparatus, the quality and quantity of character data taken out from a medium called a form to be read are evaluated. Here, the character data is the result of character recognition of image data obtained by optically scanning a form, and the reading performance greatly depends on the recognition performance.

However, in order to improve the quantitative aspect of the reading performance, that is, to increase the amount of a form for retrieving character data per unit time, it is necessary to not only increase the speed of character recognition but also improve the transport speed and the transport interval. By packing and sending, it is required to increase the amount of forms to be conveyed per unit time. The same applies to a case where a larger number of articles are processed per unit time in an automatic mail processing apparatus or the like.

[0004] When transported at high speed at short intervals, there is a probability that the transported object will collide with or overlap with the preceding or following transported object, misalignment of position tracking with the transported object due to deviation from the transport path, or damage to the transported item due to jam. Get higher. Therefore, high-accuracy position tracking that allows early detection of transport abnormalities is required.

In order to improve the accuracy of position tracking, the number of detectors provided along the transport path for detecting the passage of a transported object may be increased. However, since an increase in the number of detectors leads to an increase in the cost of the apparatus, a method is used in which the number of detectors is reduced and information that can determine the transport state from the output of the detector is generated and used. .

As a conventional position tracking method, as shown in a block diagram of FIG. 4, a first detection is performed to detect each of a plurality of objects to be tracked at an entrance and an exit of a conveyance path having a predetermined length. Means 121 and second detection means 1
22, a first measuring means 131 for obtaining a length and a transport interval for each transported article based on the output of the first detecting means 121, and a A first storage unit 141 that assigns and holds and updates a code for each conveyed product, and identifies a length of each conveyed product obtained by the first measuring unit 131 and a measured value of a conveyance interval with a subsequent conveyed product. A second storage unit 142 that stores the code corresponding to the code; and a second measurement unit 132 that calculates a predicted value of an interval until the leading end of the first transported object in the transport path reaches the second detection unit 122. The second measuring means 132 includes a first detecting means 121 and a second detecting means 12.
With the value corresponding to the interval to 2 as an initial value, while counting down according to the output of the first detecting means 121, the predicted value of the interval until the leading end of the conveyed object reaches the second detecting means 122 is changed. There is a method of tracking the position of each conveyed object on the conveyance path by updating the position of the object (Japanese Patent Application No. 14/1985).
No. 1716).

On the other hand, in an optical character reading device, the transport speed of a reading unit that optically scans a form while transporting a form and takes in image data changes according to the reading mode.
For example, in a reading mode that requires high-definition image data, the transport speed is reduced to 1 / N as compared with the normal, and the dot density is increased to N times the normal. In the reading mode requiring high-speed processing, the dot density becomes coarser than normal by increasing the transport speed N times as compared with the normal, but the image data for the form N times the normal is stored in the image memory. I do.
However, N> 1.

As described above, since the change in the transport speed of the reading unit directly affects the image data to be captured, a transport mechanism capable of controlling the transport speed with high precision is employed in the reading unit.
On the other hand, the upstream transport system that supplies the form to the reading unit and the downstream transport system that discharges the form after capturing the image data are within the range that does not cause inconsistency in the position tracking of the conveyed object or jam. If so, a change in the transport speed can be tolerated. Therefore, a mechanism simpler than the transport mechanism of the reading unit is employed to reduce the cost of the apparatus.

Therefore, even if the transport system of the reading unit and the upstream and downstream thereof are controlled in conjunction with the reading operation,
Since a difference in transport speed or a time difference occurs when the transport operation is switched, the transport interval between the two transport systems when the preceding and following transport objects are transported to different transport systems changes.

[0010]

In this conventional position tracking method for a conveyed article, the predicted value of the interval until the leading end of the first conveyed article in the conveying path reaches the detecting means provided at the exit is changed. Since the position of each conveyed object is tracked and updated, the accuracy of position tracking is improved and early detection of a conveyance abnormality can be realized, but the conveyance interval cannot be adjusted.

For example, even if an error occurs in the predicted value of arrival at the exit due to factors such as the friction coefficient of the transportation system and the transportation speed when the leading end of the transported article actually reaches the exit detection means,
The error can correct the predicted arrival value of the succeeding transported object, but cannot feed back the control of the transport speed.

In the case of carrying over a plurality of carrying systems, even if the carrying interval is changed due to a difference in carrying speed between the upstream and downstream carrying systems and a time difference at the time of switching the carrying operation, the carrying is performed. It was not possible to dynamically correct fluctuations in the medium transport interval.

[0013]

According to the present invention, there is provided a method for tracking the position of a conveyed object, comprising a first method for conveying the conveyed object to a second conveying system.
A first transport system having a driving source of
First for receiving from the system and transporting to the third transport system
A second drive source driven at the same speed as the drive source and the
A first detecting means for detecting passage on the second transport system;
Receiving the goods from the second transport system and the second transport system
Third drive source for transport and third transport system for transported objects
The position of the conveyed object provided with the second detecting means for detecting the passage above
A position tracking method, wherein the first transport system switches from the second transport system to the second transport system.
When the end of the conveyed article has passed the first detection means
At which point the first drive source stops and then the first drive source again
By the time driving starts, the transported object whose end is detected
Advance by the second drive source while one drive source is stopped
First detection from the distance and the tip of the conveyed object on the first conveying system
Objects on the second conveyance system based on the distance to the means
Of the first transport interval and the transported object on the second transport system
From the first measuring means for determining the length of the
Distance to the second detection means,
A second drive source from when the tip has passed the first detection means;
The time during which was driven, at least the transported object on the third transport system
Length and the tip of the conveyed object on the third conveying system
A second transport system based on the distance that has advanced beyond the knowledge means;
Set the second transport interval between the transported objects over the third transport system.
The second measuring means to be obtained and the first transport interval are set to the first setting
When the value is equal to or larger than the value, the first drive source is activated.
If the first transport interval is less than the first set value
The first driving source is stopped, and the second conveyance interval is set to the second set value.
If it is larger, the second drive source is activated and the second drive source is activated.
Transport interval is shorter than the third set value than the second set value
And determining means for stopping the second drive source if the distance is smaller .

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention. There are a transport system 11, a transport system 12, and a transport system 13 from upstream to downstream along the transport direction. Each transport system controls a controller 71 that controls a motor MT1 that is a drive source of the transport system, a controller 72 that controls a motor MT2 that is a drive source of the transport system, and controls a motor MT3 that is a drive source of the transport system. It has a control unit 73, and can independently control the transport operation of each transport system. The transport system 12 is a photoelectric sensor (PH
1) 21, a measurement counter CTLG31, registers (RGTR1 to 4) 41 to 44, a memory 49, a calculation unit 50, and a determination unit 60.

The photoelectric sensor (PH1) 21 is connected to the transport system 12
Is a detecting means for detecting a form passing through the form. The measurement counter CTLG31 receives the information from the photoelectric sensor (PH1) 21 as to whether or not a form is present on the sensor, and the transport operation state and the information indicating the transport speed from the MT2 control unit 72, and receives the length of the form. Alternatively, it is a measuring means for measuring a transport interval. That is, if the transport speed of the form while passing over the photoelectric sensor (PH1) 21 is v [cm / sec] and the transport time required for passage is t [sec], the form length l
[Cm] is 1 [cm] = v [cm / sec] × t [se
c].

Similarly, the transport interval is given by the transport speed and the transport time from the end of the preceding form past the photoelectric sensor (PH1) 21 to the leading end of the next form reaching the photoelectric sensor (PH1) 21. Ask. Here, the transport time is MT2
This is the time during which the controller 72 drives the MT2.

The registers (RGTR1 to 4) 41 to 44 are storage means for holding a code for identifying a form in order to clarify the order of conveyance of the form on the transport system 12. The maximum number of retained codes is equal to the maximum number of forms that can be normally transported by the transport system 12, and is set to four in this embodiment. There are four registers from (RGTR1) 41 to (RGTR4) 44 from upstream to downstream. If there is only one form on the transport system, (RGTR1) 41 holds the code given to that form.

When the photoelectric sensor (PH1) 21 detects that a new form has entered the transport system, the code held in the (RGTR1) 41 up to that point is (RGTR1).
(RGTR1) 41, and the (RGTR1) 41 holds the code of the newly entered form. When a new form enters the transport system, the code of the first form held in (RGTR2) 42 is shifted to (RGTR3) 43 and the code shifted to (RGTR1) 41 is changed to (RGTR2). ) 42, and (RGTR1) 41 holds the code of the new form.

In addition, when a new form enters, the code of the first form is shifted to (RGTR4) 44, and the code is sequentially shifted between the registers. The photoelectric sensor (PH2) 2 notifies that the first form has reached the transport system 13.
Upon detection by the output of 2, the contents of the register holding the code of the first form are cleared to 0 after being passed to the register of the transport system 13.

The storage unit has a memory 49 for storing the length of the form measured by the length / interval measurement counter (CTLG) 31 for each form, and the identification code assigned to the form is used to store the measured value. Deriving the stored address. The calculation unit 50 performs a calculation for dynamically estimating a transfer interval that changes during transfer. That is, the photoelectric sensor (PH1)
The output system 21 captures the passage timing of the form, and, based on the transport operation state and the transport speed from the MT2 control unit 72, according to the transport order according to the contents of the registers (RGTR1 to 4) 41 to 44, based on the transport system. Estimate the distance until the leading end of the form on (12) reaches (PH2) 22.

Since the transport interval between the transport system 12 and the transport system 13 changes depending on the movement of the end position of the form on the transport system 13, the measurement counter (CT) of the transport system 13 is used.
(RS) 32 and the control information indicating the transport operation state and the transport speed from the MT3 control unit 73, as well as the amount of the leading end of the report passing through (PH2) 22 and the end position of the report on the transport system 13 is estimated. . From the estimation results of these form positions, a transfer interval that changes during transfer is obtained in real time.

The determination unit 60 monitors the estimated value of the transport interval obtained by the arithmetic unit 50, feeds back to the MT1 control unit 71 and the MT2 control unit 72 if necessary, Is larger than (PH2) 22 and the magnitude of the difference from the estimation result is confirmed to detect the occurrence of the transport abnormality.

Next, with reference to the conceptual diagram of one embodiment of the present invention shown in FIG. 2, a description will be given of the calculation for obtaining the transport interval and the feedback of the result to the control means.

There are a transport system 11, a transport system 12, and a transport system 13 along the transport direction. Each transport operation is performed by motors (MT1) 91, (MT2) 92, (MT
3) It is controlled by controlling 93. The transport system 13 is a reading unit that optically scans the form while transporting the form and captures image data into the CCD scanner 90.

Transport interval (G1) 5 in transport system 12
1 drives (MT2) 92 so that the end of the form is (PH)
1) After the passage of a certain distance past 21 is measured by (CTLG) 31, (MT1) 91 is driven, and the next form is supplied from the transport system 11 (MT1) 91 and (MT2).
92.

Transport interval (G2) 5 in transport system 13
2 is determined by the operations of (MT2) 92 and (MT3) 93.

For example, as shown in the drawing, the transport system 11 has a form A85, and the transport system 12 has a form X82 and a form Y8.
3, when the form Z84, there is form W81 is the transport system 13, the code "C _A" to the respective form, "C _X", "C _Y"
“C _Z ” and “C _W ” are assigned and identified. The transfer speed of the transfer system 11 and the transfer system 12 is a constant speed v
_F [cm / sec], the transport speed of the transport system 13 is v _R1 ~
It can be changed to three stages of v _R3 [cm / sec].

[0029] At this time, determined by the conveyance interval 51 on the transport system 12 and _{G 1 G 1 = v F ×} t F1 + d [cm] = CTLG + d.

However, t _F1 [sec] is stopped when the end of the form has passed (PH1) 21 (MT1) 9
This is the time when the (MT2) 92 is driven until the driving of the (MT2) 92 starts again in accordance with the operation of the (MT2) 92. (V _F
× t _F1 ), that is, the distance that the terminal has advanced during that time is (CT
LG) 31. Also, d [cm] is how far the leading end of the form in the transport system is from (PH1) 21 and the distance thereof. The determination unit monitors the transport interval (G1) 51, and (G1) 51 determines the set value m1.
By starting (MT1) 91 at the time of reaching [cm], the transport interval 51 in the transport system 12 can be controlled to a constant value m1 [cm].

On the other hand, when the transport distance 52 across the conveying system 12 and the transport system 13 and _{G2 G2 = (D-v F} × t F2) - defined by _{{L-Σ (v Ri ×} t Ri)} [cm] . i = 1 to 3. However, D [c
m] is the distance from (PH1) 21 to (PH2) 22. t _F2 [sec] is the time during which (MT2) is driven after the leading end of the form has passed (PH1) 21. Subtracting tip the D [cm] at the tip position tracking counter (CTTR) 59 when it reaches the (PH1) 21 leave preset as an initial value, the amount corresponding to the distance traveled (v _F × t _F2) then Thus, the position of the leading end of the form is estimated. In this embodiment, (CTTR) 59 is provided for each form.

L [cm] is the form length measured by (CTLG) 31 based on the output of (PH1) 21 and is stored in the memory 49 at the address derived from the form identification code. For example, L (W) is a measured value of the form W, and a memory address is derived from the code _CW . t _R1 ~t _R3 [sec] is the tip of the form is (PH2) 2
This is the time during which (MT3) 93 has been driven after passing through No. 2. t _R1 is the time driven at the transport speed v _R1 [cm / sec], t _R2 is the time driven at the transport speed v _R2 [cm / sec], and t _R3 is the time driven at the transport speed v _R3 [cm / sec]. And The distance that the leading end of the form has advanced beyond (PH2) 22 is Σ (v _Ri × t _Ri ), and is measured by (CTRS) 32. i = 1 to 3.

In the determination means, the transfer interval (G2)
52 is monitored, and when (G2) 52 exceeds the set value m2B [cm], (MT2) 92 is activated and (G2) 52 is started.
Becomes smaller than the set value m2A [cm] (MT
2) By stopping 92, the transport interval (G2) 52 extending between the transport system 12 and the transport system 13 is set to m2A to m2.
It can be controlled during B [cm]. However, m2A <m2B [cm].

The operation of the above-described embodiment of the present invention will be described with reference to the flowcharts of FIGS. 3 (a) and 3 (b). Also, this flowchart is for a fixed time t ₀ [ms
ec] is shown. First, a state change of PH1 is checked (step 20).
0). If the leading end of the form is detected, the contents of the CTLG are cleared to 0 (step 201), and then the identification code is shifted between the RGTRs 1 to 4 (step 202).
GTR1 is given a new identification code (step 20).
3) PH1 to CTTR of that form, that is, CTTR # 1
D [cm], which is the distance between .about.PH2, is preset (step 204). If the end of the form is detected, C
The contents of the TLG are cleared to 0 (step 205). Especially when there is no state change, whether there is a form in the transport system
The contents of the GTRs 1 to 4 are checked (step 206). If there is no form, the countdown of the CTTR, the updating of G1 and G2, and the return to the control means are skipped.

Next, the operation state of the MT2 is checked (step 210). When the MT2 is in the driving state, the transport speed v
_The movement amount (v _F × t ₀ × 10 ⁻³ ) of the form being conveyed during the processing cycle t ₀ [msec] at _F [cm / sec] (c)
m] is the CTTR of all the forms on the transport system, ie, R
CTTR of forms in GTR1-4, CTTR # 1-4
(Step 211).

Similarly, when the MT2 is in the driving state, the length of the form or the amount of change in the transport interval (v _F × t ₀ × 10) caused by the transport of the form during the processing cycle t ₀ [msec].
^-3 ) Add [cm] to CTLG (step 21)
2). Then, PH1 is checked (step 213).
If there is no report on 1, G1 = CTLG + d [cm] is obtained (step 214), and the value of G1 is checked (step 215).

If G1 is equal to or greater than the set value m1 [cm], MT1 is activated (step 216), and control is performed so that G1 does not open any more. If G1 is less than the set value m1 [cm], MT
1 is stopped (step 217) to increase the interval.

To update G2, first, the presence or absence of a form in the transport system, that is, the reading unit is checked (step 220). If there is no form, the MT2 is started regardless of the value of G2 (step 221) and the form is read by the reading unit. Supply to If there is a form in the reading unit, the movement amount (v _R × t ₀ × 10 ^-3 ) [cm] by which the form is transported during the processing cycle t ₀ [msec] is calculated by CT.
The sum is added to the RS (step 222). Here, v _R is the transport speed of the transport system 3 and is one of v _R1 , v _R2 , and v _R3 .

Then, G2 = CTTR # x- (LC)
TRS) [cm] is obtained (step 223), and the value of G2 is checked (steps 224, 225). G2 is m2B
If it is larger than [cm], MT2 is activated (step 221) to control that G2 does not open any more. If G2 is smaller than m2A [cm], MT2 is started.
2 is stopped (step 226), and control is performed so that G2 does not become smaller. However, CTTR # x
Is the CTTR of the first form in the transport system.

Finally, the state change of PH2 is checked (step 230). If the leading end of the form is detected, the contents of CTTR # x at that time are checked (step 231) to check how much the difference is in the + or-direction with respect to 0. If the difference exceeds the limit value e [cm], it is determined that a transport abnormality has occurred, and an alarm process such as an emergency stop of the control means is performed (step 232).

If this difference is less than the limit value e [cm], it is determined that the document is in the normal transport state, and the identification code of the form that has reached PH2, that is, the register RGTRx in which the identification code of the first form in the transport system is stored. After shifting the contents to the register RGTR5 of the transport system (step 233), RGTRx is cleared to 0 (step 234).
When the difference is less than the limit value e [cm], the value of another CTTR is corrected by the difference (step 235), so that an error due to a difference in the transport speed and a difference in the transport operation depending on the reading mode are performed. A high-accuracy position tracking is realized in consideration of an error generated from the position.

In this embodiment, in order to estimate and track the leading edge position of the form in the transport system, the form position is calculated from the leading position for each form.
A counter CTTR indicating the estimated distance to H2;
All of them are constantly updated according to the transport operation of T2. In this case, there is an advantage that the leading end positions of all the forms can be grasped, but the number of processes is increased because the CTTR is updated every time the number of the forms. On the other hand, it is also possible to use only one CTTR so as to track only the first form. In this case, the leading end position of the following form in the transport system is obtained based on the form length measured at PH1 and stored in the memory and the transport interval G1 controlled during supply.

[0043]

As described above, according to the present invention, the output of the detecting means, the measured value held in the storage means, the measured value obtained from the measuring means of another transport system, and the control of the own and other transport systems are provided. Based on the control information obtained from the means, dynamically estimate the transport interval that changes during transport, improve the accuracy of position tracking, and apply feedback to the control means so that the transport interval is within the set range while monitoring the transport interval. Accordingly, the fluctuation of the transport interval during the transport can be dynamically corrected, so that the transport can be performed while maintaining the short transport interval.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a conceptual diagram of one embodiment of the present invention.

FIGS. 3A and 3B are flow charts of one embodiment of the present invention.

FIG. 4 is a block diagram of a conventional example.

[Explanation of symbols]

 Reference Signs List 11 transport system 12 transport system 13 transport system 21 photoelectric sensor PH1 22 photoelectric sensor PH2 31 length / interval measurement counter CTLG 32 PH2 passage amount measurement counter CTRS 41 identification code holding register RGTR1 42 RGTR2 43 RGTR3 44 RGTR4 45 RGTR5 49 Memory 50 Operation unit 51 Transfer interval G1 during feeding in the transfer system 52 Transfer interval G2 across the transfer system and transfer system 59 Tip position tracking counter CTTR 60 Judgment unit 71 Motor MT1 control unit 72 Motor MT2 control unit 73 Motor MT3 control unit 81 Form W 82 Form X 83 Form Y 84 Form Z 85 Form A 90 CCD scanner 91 Motor MT1 92 Motor MT2 93 Motor MT3 121 First detection means (entrance) 122 Second detection means (exit) 131 First measuring means 132 Second measuring means 141 First storing means 142 Second storing means 201-235 Step

Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G06K 9/20 G06K 13/067 B65G 43/08 B65H 7/06

Claims (2)

(57) [Claims] 1. A first transport system having a first drive source for transporting a transported object to a second transport system, and a third transport system receiving the transported object from the first transport system. second conveying system comprising a first detecting means for detecting the passage on the first of the second drive source and the second transport system of the conveyed object to be driven at the same speed as the driving source for conveying the And a third driving source for receiving and transporting the transported object from the second transporting system, and a second detection unit for detecting the passage of the transported object on the third transporting system, the position tracking of the transported object. Wherein the first drive source is turned off when the end of the conveyed material conveyed from the first conveyance system to the second conveyance system passes through the first detection means. stop, then to said first drive source starts driving again, the conveying product terminally detected before
The second drive source is based on the distance traveled by the second drive source while the first drive source is stopped and the distance from the tip of the conveyed object on the first conveyance system to the first detection means. A first transport interval between the transported objects on the transport system, and the second transport interval.
A first measuring unit for determining the length of a conveyed object on a conveying system, a distance from the first detecting unit to the second detecting unit, and a tip of the conveyed object on the first conveying system is The time during which the second drive source has been driven since passing through the first detecting means, at least the length of the transported object on the third transport system, and the transported object on the third transport system The tip of the second
Based on the distance that has proceeded beyond the detecting means of the second transport system and the second transport system between the second transport system and the third transport system.
A second measuring means for determining the transport interval of the first and the second transport interval, when the first transport interval is equal to or greater than the first set value,
Activating the first drive source, stopping the first drive source if the first transport interval is less than the first set value, and setting the second transport interval to a second set value If it is larger than the second drive source, the second drive source is activated. If the second transport interval is smaller than a third set value shorter than the second set value, the second drive source is started. And a determining means for stopping the source. 2. A distance measured from a distance between the first detecting means and the second detecting means and a time measured from a time when a leading end of a conveyed object on the first conveying system has passed through the first detecting means. The distance from the second detection means to the conveyed object is stored as an estimated value based on the estimated value, and when the leading end of the conveyed object actually passes through the second detection means, the estimated value indicates the limit value. When the value exceeds the limit value, the transfer error state is set, and when the estimated value is less than the limit value, a normal transfer state is set and the stored estimated value is corrected based on a difference from the limit value. The method for tracking the position of a conveyed product according to claim 1 .