JPH0815927B2 - Control method of rotating shelf - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a rotary shelf in which a large number of endless cargo receiving trays (tray etc.) can be rotated in a horizontal or vertical circulation path. In this regard, the present invention relates to a rotary rack control method for automatically calling an arbitrary load receiving tray to the load transfer station.

(Prior Art and Problems Thereof) In the conventional control method for the rotary rack as described above, a motor for rotating the loading tray is linked with a pulse encoder or the like, and the pulse generated by the pulse encoder is normally rotated. A pulse counting method for performing deceleration stop control of the rotating load receiving base based on the difference between the current count value and the target count value corresponding to the calling load receiving base, The passing cargo cradle is counted during forward rotation and subtracted during reverse rotation, and the rotating cargo cradle is decelerated and stopped based on the difference between the current count value and the target count value corresponding to the calling cargo cradle. A pedestal counting system is known.

In the former pulse counting method, since the count value becomes very large, the cost of means for counting, calculating and storing becomes high. Further, in the loading platform counting method, it is not possible to set each control position of deceleration stop more finely than the loading platform pitch, so that it is not possible to suppress the traveling distance at medium speed and low speed to the necessary minimum, particularly, When the pitch between the loading trays is large, there is a drawback that the deceleration rotation distance becomes long and the time required to call the loading tray becomes long.

(Means for Solving Problems) The present invention proposes a method of controlling a rotary shelf that can solve the above-mentioned conventional problems, and is characterized by a large number of endless cargo receiving trays. In a rotating rack that can be rotated in the circulation path, the detection plates of the same length are attached to each load receiving platform, and the front end and the rear end of the detection plates are detected simultaneously at a fixed position. A pair of front and rear detectors are arranged at an interval to obtain, and when the load receiving tray is normally rotated by the counting means, when the detection signal of the front end detector falls, when the detection signal of the rear end detector falls, and When the detection signal of the front end detector rises, 1/4 is added and counted, and the passing pedestal is incremented by 1 so that the count value of the pedestal is incremented by 1 due to the next rise of the detection signal of the rear end detector. When the receiving tray is reversed, subtract the opposite of the above. The present count value including the fraction of 1/4 unit is obtained by counting, and from the present count value obtained by the counting means by the calculation means and the target count value corresponding to the set call receiving tray, 1 From the time when the remaining turning distance of the value including the fraction of / 4 unit is calculated, and the remaining turning distance obtained by the calculating means by the control means becomes the set value of the value including the fraction of 1/4 unit The point is to perform deceleration control or stop control of the rotating load carrier after a preset delay time has elapsed.

In implementing the present invention, the delay time is set to a second delay time that is longer than the normal set time, and the second delay time is used only when the loading platform is close. The deceleration control timing can be delayed.

(Example) Hereinafter, one example of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 is a rotary shelf, and a drive chain 2
It is equipped with a large number of trays 3a to 3c connected endlessly. The drive chain 2 is driven in a forward or reverse direction by a motor 5 whose speed is controlled by an inverter 4. Reference numeral 6 denotes a detection device provided side by side at one position in the circulation path of the trays 3a to 3c, and as shown in FIGS. 2 and 3, a front end detector 7, a rear end detector 8, and a parity detection device. It is equipped with a container 9. The detection signal of the detection device 6 is input to the computer 10. Reference numeral 11 denotes a D / A converter, which converts the speed control digital signal from the computer 10 into an analog signal and supplies the analog signal to the inverter 4.

As shown in FIG. 2 and FIG. 3, an upward U-shaped detection plate 12a is attached to the origin tray (No.1 tray) 3a, and a wide detection plate 12b is attached to the even-numbered tray 3b. A small width detection target plate 12c is attached to the odd-numbered trays 3c except the origin tray 3a. All of these detected plates 12a to 12c have the same length and are provided in parallel with the tray moving direction. The front end detector 7 and the rear end detector 8 are arranged so that the front and rear end portions of each of the detected plates 12a to 12c are simultaneously detected. Parity detectors 9 are arranged side by side at a detectable interval, and the parity detector 9 is an upward U-shaped detection target plate.
The height is high enough to detect only the protrusions on both ends of 12a and the upper half of the wide detection plate 12b, and it is arranged at an intermediate position between the front and rear detectors 7, 8.

In the above structure, when the rotary shelf 1 is rotated by the motor 5 via the drive chain 2 in the normal rotation direction shown in FIG. 2, each time the trays 3a to 3c pass the detection position, As shown in FIG. 4A, the detection signal F of the front end detector 7 and the detection signal B of the rear end detector 8 are preceded by the detection signal F and both detection signals F and B partially overlap with each other in time. Output. If a circuit that outputs a pulse signal C at the time of rising and falling of both detection signals F and B is used together, four pulse signals C of a to d are generated every time each tray 3a to 3c passes the detection position. can get. On the other hand, when the origin tray 3a passes, the detection signal P1 is output from the parity detector 9 between a and b of the pulse signal C and between c and d, and the even number tray 3
When b passes, the detection signal P2 from the parity detector 9 is output straddling between b and c of the pulse signal C. When an odd-numbered tray 3c other than the origin tray 3a passes, no detection signal is output from the parity detector 9.

When the rotary shelf 1 is rotated in the reverse direction shown in FIG. 2, the detection signal F of the front end detector 7 is detected as shown in FIG.
The output timings of both detection signals F and B are reversed, so that the detection signal B of the trailing edge detector 8 precedes, and other conditions are the same as those in the normal rotation. Therefore, as in the case of normal rotation, four pulse signals C'a 'to d'are obtained each time each tray 3a to 3c passes the detection position.

Further, a circuit that outputs the fixed position signal D when both the detection signals F and B are output is also used, and the fixed position detection of each of the trays 3a to 3c is performed by the output of the fixed position signal D.

However, in the computer 10 which takes in the detection signal of the detection device 6, the pulse signal Cb of
"N", pulse c "N + 1/4", pulse d "N + 2/4", next pulse signal C a "N + 3/4", and pulse b "N + 1". 1/4 for a to d of signal C
Increment and count one by one, and at the time of reverse rotation, "N" at b'of the pulse signal C, "N-1 / 4" at c ', and "N-2 / 4" at d',
A'-d 'of the pulse signal C, such as "N-3 / 4" at a'of the next pulse signal C and "N-1" at the next b'.
Then, 1/4 is subtracted from each, and the integer value corresponding to the tray number is "+1" or "-" when the fixed position signal D rises.
A current count value is obtained with a fractional (decimal) value that increments by "1" and increments by "+1/4" or "-1/4".

Also, between a and b of the pulse signal C (between a'and b'in reverse rotation)
When there is a detection signal P1 at the same point (b 'at the time of reverse rotation) and no detection signal P2 at the same time, it is judged as the origin tray 3a, and at the time of forward rotation, the pulse signal b at that time (rising of the fixed position signal D)
The current count value is reset from "Nmax + 3/4" to "1" with the current count value being "1" at the time of reverse rotation, and the next subtracted integer value is the maximum value corresponding to the maximum tray number. Preset to "Nmax".

In addition, between b and c of the pulse signal C (b'and c'during reverse rotation)
When there is a detection signal P2 in, it is judged as an even number tray 3b,
If there is no detection signal P2 between b and c of pulse signal C (b 'and c'when reversing), odd number tray 3 other than origin tray 3a
Since it can be judged as c, based on this judgment,
The integer value of the current count value at that time is checked, and if the even-numbered and odd-numbered relationships do not match, a processing such as an emergency stop can be taken as a counting error.

The method of controlling the deceleration stop of the rotary shelf 1 using the present count value obtained as described above will be specifically described. In the computer 10, the tray to be called to the detection position.
When the No. is set, the rotation direction is determined based on the difference between the target count value corresponding to the calling tray No. and the current count value, etc., and the motor 5 is started based on this, and the drive chain 2 is driven. The trays 3a to 3c are rotated in a predetermined direction via the trays. Due to the rotation of the trays 3a to 3c, the current count value indicating the tray number (integer value) corresponding to the detection position and its detailed position (fractional value) changes momentarily as described above, but deceleration is performed. Regarding the stop control, as shown in the flowchart of FIG. 5 and the graph of FIG. 6, the absolute value of the difference between the target count value J and the present count value K which changes every moment, that is, the tray rotation remaining distance value L is used. , High-speed → medium-speed deceleration control device X, medium-speed → low-speed deceleration control position Y, and low-speed → stop control position Z are respectively set in advance, and the actual deceleration or stop is performed from each control position X to Z. The delay times Tx, Ty, Tz are preset respectively. Here, regarding the delay time Ty from the medium speed → low speed deceleration control position Y, the normally used first delay time Ty
1 and the second delay time Ty2 longer than this first delay time Ty1
And are set.

However, due to the rotation of the trays 3a to 3c, the tray rotation remaining distance value L calculated as described above becomes high speed after the delay time Tx has elapsed from the time when the tray rotation residual distance value L reaches the set value X (for example, 4 + 1/4). To medium speed, and the tray rotation remaining distance value L
After the delay time Ty1 or Ty2 has elapsed from when the set value becomes the set value Y (for example, 2 + 3/4), the speed is decelerated from medium speed to low speed,
Then, the tray rotation remaining distance value L is set to a set value Z (for example, 0 + 3 /
The stop control is performed after the delay time Tz has elapsed from the time point 4). By this deceleration stop control, the tray of the set tray number stops at the detection position, the current count value at this time is the same as the tray number, and the fractional value is not included.

The delay times Ty1 and Ty2 are properly used as follows.
That is, as shown in FIG. 7, the calling tray moves to the above-mentioned high-speed → medium-speed deceleration control position X (4 + 1 / T at the tray rotation remaining distance value L
When it is close to 4), for example, at the -5 position (the position before 5 trays) or the -4 position, it is a rotation that can accelerate the calling tray to a medium speed or a speed close to a medium speed like a line or a line. The distance can be secured, but the calling tray is at the medium speed →
Low speed deceleration control position Y (2 + 3 / with tray rotation remaining distance value L
4) When the call tray is at a position slightly distant from the control side, for example, at the -3 position, the calling tray passes through the control position Y shortly after the call is made, and the normal delay time Ty1 elapses at a level slightly exceeding the low speed. Since the vehicle is decelerated to a low speed, the turning distance at a low speed as shown by the line becomes longer than in the normal case. In such a case, by delaying the deceleration timing to low speed by using the second delay time Ty2 longer than the delay time Ty1, after sufficiently accelerating as shown by the line, decelerating to low speed, and then at low speed. The turning distance can be the same as or close to that of the normal time. Call tray is at -2 position or
When in the 1 position, the medium speed → low speed deceleration control position Y (2 + 3 /
4) Since it is closer to the detection position, it can be accelerated only from the beginning to low speed.

That is, when the calling tray is started from the -3 position, it is not actually accelerated to the middle speed due to the relationship of the acceleration, despite the position of the condition of being accelerated to the middle speed, and the turning distance at the low speed is particularly long. Become. Therefore, as shown in the flowchart of FIG. 5, the tray rotation remaining distance value L becomes the set value Y (2 + 3/4) depending on whether or not the total rotation distance of the calling tray is a short distance rotation of 3 counts. If it is not short-distance rotation, the first delay time Ty1 is set, and if it is short-distance rotation, the second delay time Ty2 is set.
After the elapse of y1 or Ty2, deceleration control to low speed is performed.

The calculation of the tray rotation remaining distance L and the set values X to Z are performed.
The comparison processing with or, the determination of whether or not the short-distance rotation or the like is performed in the computer 10, the high → middle deceleration signal, medium → output from the computer 10 based on this processing.
Digital signals for speed control such as a low deceleration signal and a stop signal are converted into analog signals by the D / A converter 11 and supplied to the inverter 4 to control the motor 5. or,
Calling the tray You can check if the tray has stopped in place.

In the above embodiment, the detection device 6 is controlled to call the tray of the set tray number at the detection position where it is installed, but the load transfer station is set to a different position from the detection position. When the load transfer station is set, the tray number to be called is set and the detection position is determined from the distance (the number of trays) between the load transfer station and the detection position and the set call tray number. The tray number to be called up is calculated, and the control of the above-described embodiment may be performed based on this result.

In addition, in the addition / subtraction counter that counts the pulse signal C, the maximum value that is preset from 1 is automatically restored from the maximum value that was preset in advance during forward rotation in which addition and counting are performed and in the reverse rotation that is performed in subtraction counting. Since it automatically returns to the value, the determination of the origin tray 3a is not an essential condition. Furthermore, whether it is an even No. tray 3b or an odd No. tray 3c
The function of discriminating whether or not is not essential, and can be omitted if not necessary.

(Operation and Effect of the Invention) As described above, according to the control method of the rotary shelf of the present invention, the counting means (in the embodiment, all the calculating means and the controlling means other than this counting means are embodied by the computer 10). Is the same as the current count value in the conventional pallet counter counting method that simply counts the number of pallets that have passed.
Since it can correspond to o., it can be specially compared with the set call receiving bed No., and although it can be controlled more easily than the conventional pulse counting method, By using a fractional value of 4 units, it is possible to finely detect the position of the pallet with each division point that divides the adjacent pallets as 4 as the minimum unit.

Therefore, the setting of each control position (shift position, stop braking position, etc.) for deceleration stop control can be set finely by using the minimum unit of the fraction, and the deceleration rotation distance is the minimum required even if the pitch between the receiving trays is large. Although it is possible to shorten the time required for calling the cargo receiving tray by setting the limit to the limit, the maximum effect of the present invention is as follows.

That is, as described above, the current count value has an integer value part that can be associated with each pallet No. and a fractional part that can be associated with each division point that divides each pallet into a plurality of parts. By doing so, it is possible to improve the demerits while finely performing deceleration and stop control while obtaining the merits of the conventional loading platform counting method.
As a method to give the current count value a fractional part that can correspond to each dividing point that divides each receiving cradle into multiple parts, attach a plate to be detected at each dividing point that divides the adjacent receiving cradle , A generally considered method of detecting this with a detector, i.e., a method of making the pitch of the plates to be detected finer than the pitch of the pedestal, if the number of plates to be detected is smaller than that of the pedestal. It is necessary to install the plate to be detected that is placed between the load receiving bases in a chain or the like that connects the load receiving bases, which not only complicates the structure but also leads to a significant increase in cost. It is not possible to change only the control method by directly utilizing the rotary shelf of the conventional structure in which one plate to be detected is attached to each of the receiving trays.

According to the configuration of the present invention, however, the detection plates having the same length are attached to each of the load receiving trays, and a pair of front and rear detectors are provided at a constant position so that the front end and the rear end of the detection plates can be simultaneously detected. The existing rotating rack (for example, the rotating rack described in Japanese Patent Laid-Open No. 59-36017) is used as it is, that is, the plate to be detected is added or the arrangement of the detectors is changed. With no need at all, simply change the counting calculation processing method by the counting means and the calculating means (these are also necessary for the implementation of the conventional control method), and each dividing point that divides each receiving platform into a plurality of points. Therefore, the deceleration stop control can be finely performed by providing the present count value with a fractional part that can correspond to the above.

However, even if the deceleration stop control can be performed finely, the minimum unit of the fractional part of the present count value is 1/4, which is too large to be compared with the minimum unit in the conventional pulse counting method.

In view of this point, the present invention further combines time control, which does not lead to a cost increase in terms of hardware,
The deceleration stop control can be performed more finely.

That is, since the deceleration control or the stop control is performed after the preset delay time has elapsed from the time when the remaining rotation distance of the load receiving tray (the tray of the embodiment) reaches the set value, the deceleration control or the final deceleration control is performed. The position of the loading tray when performing the stop control can be arbitrarily set regardless of the position represented by the current count value including the fractional value whose minimum unit is 1/4.

In other words, although it has a very simple structure and can be implemented at a very low cost, it has become possible to perform an extremely fine deceleration stop control comparable to the pulse counting method.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining the overall configuration, FIG. 2 is a front view showing a plate to be detected and a detector of each tray, FIG. 3 is a side view of the same, and FIGS. FIG. 5 is a flowchart for explaining a deceleration stop control method, and FIGS. 6 and 7 are velocity diagrams during deceleration stop control. 1 ... Rotary shelf, 2 ... Drive chain, 3a ... Origin tray (No.1 tray), 3b ... Even No. tray, 3c ... Odd odd number tray except origin tray, 4 ... Inverter, 5 …
… Motor, 6 …… Detecting device, 7 …… Front end detector, 8…
… Rear end detector, 9 …… Parity detector, 10 …… Computer, 11 …… D / A converter.

Claims (2)

[Claims] 1. In a rotary shelf in which a large number of endlessly-shaped load receiving bases can be rotated in a circulation path, each load receiving base is attached with a plate to be detected and at a fixed position. The front and rear ends of the plate to be detected are provided with a pair of front and rear detectors at intervals that can be detected at the same time, and by the counting means, when the load receiving tray is normally rotated, when the detection signal of the front end detector falls, When the detection signal of the trailing edge detector falls and when the detection signal of the leading edge detector rises, 1/4 is added and counted respectively, and the counter value of the receiving platform is only 1 when the detection signal of the next trailing edge detector rises. By counting the passing pedestal so that it steps up, and when the pedestal reverses, the current counting value including the fraction of 1/4 unit is obtained by subtracting and counting in the reverse of the above. The current count value obtained by the means,
From the target count value corresponding to the set call receiving cradle, the remaining turning distance of the value including the fraction of 1/4 unit is calculated, and by the control means, the remaining turning distance obtained by the calculating means is
A rotating rack characterized by performing deceleration control or stop control of a rotating receiving tray after a preset delay time has elapsed from the time when a set value including a fraction of 1/4 unit is reached. Control method. 2. The delay time is set to a second delay time which is longer than a normal set time, and the deceleration control timing is delayed by using the second delay time only when the loading platform is close. The method for controlling a carousel according to claim 1.