JPH0815925B2 - Control method of rotating shelf - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of controlling a carousel provided with a large number of load carriers that can be rotated in the normal and reverse directions on a circulation path, and particularly to a motor for driving the load carrier rotation. Based on the current value obtained by adding the pulse from the pulse transmission means when the load receiving tray rotates forward and subtracting it when rotating reversely and the stop target value corresponding to the calling load receiving tray, the calling load receiving tray is set at a predetermined position. The present invention relates to a control method for controlling the motor so as to call.

(Prior Art and Problems Thereof) The carousel as described above is one in which an endless chain that connects endlessly the respective receiving trays is rotated to move the receiving trays on the circulation path. The transmission system with the motor output shaft includes play in the lengthwise direction of the chain itself (play between the chain links), play between the chain and the drive toothed wheels, and a reducer between the drive toothed wheels and the motor. There is a relatively large amount of play consisting of the total of backlash of gears in.
This play, when the direction of rotation of the cradle changes,
It appears as a slip from the rotation of the motor to the actual movement of the cradle, that is, a delay in the movement of the cradle.

In the conventional control method of this type, for example, the control method disclosed in Japanese Patent Laid-Open No. 61-27811, the play of the transmission system between the load carrier and the motor output shaft as described above is not taken into consideration. , The following problems occurred.

That is, in this type of control method, the current from the rotating rack is calculated by adding the pulse from the pulse transmitting means interlocked with the motor for driving the rotation of the loading platform as described above when the loading platform rotates in the forward direction and subtracting it when rotating in the reverse direction. The value is calculated, but due to the movement delay of the cargo bed when the rotation direction of the cargo bed is switched, the actual position of the cargo bed is located behind the position corresponding to the current value obtained from the pulse count value. It will shift.

Due to this, in the above-mentioned conventional method, since the rotation direction of the load receiving tray has been switched, the motor is stopped in a state where the stop target value of the calling load receiving tray and the current value match. Due to the play of the power transmission system, the calling cradle was stopped before the predetermined calling position, and the calling control of the loading cradle could not be performed accurately.

(Means for Solving Problems) The present invention proposes a control method capable of solving the problems in the conventional method as described above, and its features are as follows.
In a carousel equipped with a large number of load carriers that can rotate in the normal and reverse directions on the circulation path, the pulse from the pulse transmission means interlocked with the motor for rotating the load carrier is added and reversed when the load carrier rotates in the forward direction. A method of controlling the motor so as to call the loading cradle to a predetermined position based on the current value obtained by subtraction and the stop target value corresponding to the calling cradle when rotating the loading cradle. When the direction is switched, the pulse count value corresponding to the amount of slip from the rotation of the motor to the actual movement of the load receiving base is obtained in advance as a correction value, and the rotation direction of the load receiving base is switched from normal rotation to reverse rotation. Sometimes, the correction value is added to the current value, and when the reverse rotation is switched to the normal rotation, the correction value is subtracted from the current value.

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

In FIG. 1, reference numeral 1 denotes a horizontally rotating carousel, which comprises a large number of load receiving trays, which are connected endlessly by a driving chain 2, and a tray 3. The drive chain 2
Is a motor 5 whose speed is controlled by the inverter 4.
It can be driven in any direction, forward or reverse. Reference numeral 6 denotes a pulse transmission means, that is, a pulse encoder, which is linked to the motor 5, and the pulse transmitted is counted by an addition / subtraction counter 7 that performs an addition operation when the rotary rack 1 rotates in the normal direction and a subtraction operation when the rotation shelf 1 rotates in the reverse direction. , Is input to the computer 8. Reference numeral 9 denotes a D / A converter, which converts the speed control digital signal from the computer 8 into an analog signal and supplies the analog signal to the inverter 4. Reference numeral 10 is a tray fixed position detector, 11 is an origin tray detector, and the detection signals of both detectors 10 and 11 are input to the computer 8.

As shown in FIGS. 2 and 3, both detectors 10, 11 are
Are arranged in series before and after the tray moving direction, and all the trays 3 except the No. 1 tray which is the origin tray 3a are provided with the detection target plates 12 detected by the both detectors 10 and 11, respectively. In the No. 1 tray that serves as the origin tray 3a, the portion detected by the origin tray detector 11 is
A detection plate 13 for the origin, which extends in the forward direction longer than the interval between the detection positions of 0 and 11, is attached. The plates to be detected 12,1
The lengths of the parts detected by the three detectors 10 are equal.

Therefore, when the rotary shelf 1 is rotated by the motor 5 via the drive chain 2, as shown in FIGS. 4A and 4B, the trays 3a, 3 are rotated in both forward and reverse directions. Both detectors 1 when passing the detection position where detectors 10 and 11 are installed
By detecting the plates 12 and 13 to be detected by 0 and 11, the detector 10
The detection signal 14 from and the detection signal 15 from the detector 11 are output. Both detection signals 14 and 15 are normally output sequentially without overlapping in time, but are output from the origin tray detector 11 only when the origin tray 3a, which is the No. 1 tray, passes the detection position. The tray fixed position detector 10 outputs the detection signal 14a while the origin tray detection signal 15a having a long time is output. By outputting the detection signal 14a of this condition, it is possible to detect the fixed position passage of the origin tray 3a (No. 1 tray). Incidentally, the detection signals 14a, 14 are added in the forward rotation of the rotary shelf 1 and subtracted in the reverse rotation thereof in the same manner as the transmission pulses of the pulse encoder 6 driven by the motor 5 are counted by the addition / subtraction counter 7. It is counted by the tray counting function of.

However, the rotary rack 1 is rotated in the normal direction, and as shown in FIG. 5, the addition / subtraction counter 7 is reset to zero when the detection signal 14a corresponding to the origin tray 3a rises, and the tray count value of the computer 8 is reset to zero. After that, the addition counting is performed respectively. Then, the pulse count value of the addition / subtraction counter 7 at the rising edge of each detection signal 14 is set to N.
As the absolute address 2A, 3A ... corresponding to the forward rotation fixed position (front edge of the detected plate 12) of each tray 3 after o.2, the tray count value (2, 3, ...) at that time is set. Correspondingly, it is stored in the memory of the computer 8. The absolute address 1A corresponding to the forward rotation fixed position of the origin tray 3a is zero. Furthermore, the maximum pulse count value of the addition / subtraction counter 7 immediately before the addition / subtraction counter 7 is reset to zero as described above by the rise of the detection signal 14a corresponding to the origin tray 3a after the rotation rack 1 makes one revolution, The maximum absolute address corresponding to the circumference is stored, and the maximum tray count value at the same time is stored as the maximum tray number.

Since the lengths of the portions detected by the tray fixed position detector 10 of each of the detection target plates 12 and 13 are equal, a value obtained by converting the length of the portion into a pulse count value, in other words, corresponding to the origin tray 3a. The pulse count value X of the addition / subtraction counter 7 at the fall of the detection signal 14a is added to the absolute address 1A, 2A, 3A .. It is stored in the memory of the computer 8 as absolute addresses 1B, 2B, 3B ... Corresponding to the fixed positions of the trays 3a, 3 at the time of reverse rotation (the trailing edges of the plates 12 and 13 to be detected).

At a suitable time after the rotary shelf 1 makes one round and the origin tray 3a passes the detection position again, for example, when the origin tray detection signal 15a falls as shown in FIG. Stop forward rotation. At this time, based on the pulse count value at the time point t ₁ when the stop command is output and the pulse count value at the time point t ₂ when the actual rotary rack 1 stops and the pulse count value stops advancing, the motor slip amount at the time of the stop Y is replaced with a pulse count value to calculate and store.

Next, the motor 5 is driven in the reverse direction to rotate the rotary shelf 1 in the reverse direction, and the pulse count value Z at the rise of the detection signal 14a corresponding to the origin tray 3a (corresponding to the fall in the normal rotation) is obtained. A correction value α is obtained by subtracting the value of the absolute address 1B corresponding to the reverse rotation time fixed position of the origin tray 3a previously obtained and stored from Z, and the correction value α is stored.
That is, when the rotary shelf 1 is switched from normal rotation to reverse rotation, the motor 5 rotates as shown in FIG. 7 due to the play existing in the transmission system between the tray 3 and the motor 5 as described above. Although there is a delay D between the time when the tray 3 actually moves and the pulse count value is subtracted at the same time when the reverse rotation of the motor starts, the pulse when the origin tray 3a returns to the position where the detection signal 14a actually rises. The count value is
It is a value when the origin tray 3a advances by the delay D from the position where the detection signal 14a rises. Specifically, the absolute address 1B corresponding to the length (the length from the leading edge to the trailing edge) of the portion of the plates 12 and 13 detected by the detector 10 is detected.
If the value of is "50" and the delay D is converted to a pulse count value of "30", the pulse count value is additionally subtracted by "30" when the rotary rack 1 is reversed. As a result, the pulse count value Z becomes "20". That is, the length of the portion detected by the detector 10 of the plates 12 and 13 to be detected (time length of the detection signals 14 and 14a) is converted into a pulse count value,
Although it is actually "50", it is "20" in terms of measurement. Therefore, the value of the pulse count value Z-absolute address 1B is calculated to obtain the correction value α = the delay D = “30”, which is stored.

Even when the rotation direction of the rotary shelf 1 is switched from reverse rotation to forward rotation, the same movement start delay D of the tray 3 as described above occurs, and at the time of normal rotation of the rotary shelf 1, the pulse count value is "30" by the amount of this delay. This results in extra addition. When the origin tray 3a passes the detection position in the reverse direction, the pulse count value of the addition / subtraction counter 7 is preset to the numerical value of the maximum absolute address stored from zero when the detection signal 14a falls, and the computer 8 The tray count value in is also preset from 1 to the maximum number of trays.

Although the learning work is completed as described above, the control shown in the flowchart of FIG.

If the No. 2 tray 3 is stopped at the detection position
An example of calling the No. 4 tray 3 to the detection position will be described. As shown in FIG. 9, the absolute position corresponding to the forward rotation time fixed position of the No. 4 tray 3 (the front edge of the plate 12 to be detected). Address 4A
And the absolute address 4B corresponding to the fixed position at the time of reverse rotation (the trailing edge of the plate 12 to be detected), the fixed stop position (the plate to be detected
Stop target value 4C corresponding to the 12 leading and trailing edge center positions)
Is calculated by (4A + 4B) / 2 = 4C and set. For example, the absolute address 4A is 224
0, if absolute address 4B is 2290, stop target value 4C is 2265
Becomes Further, the rotation direction of the rotary shelf 1 is determined by a conventionally known method from the current tray number (No. 2), the tray number (No. 4) to be called, and the maximum number of trays. In the case of this example, the normal rotation is performed. Further, based on the stop target value 4C = 2265, the determined rotation direction, and the stored tray slip amount Y (for example, 20) at the time of stop, the stop control position 4D = 2265
Calculate -20 = 2245 and set.

Next, the previous rotating rack rotation direction and the rotating rack rotation direction determined this time are compared, and when both rotating directions are not the same and the normal rotation is switched to the reverse rotation, the correction value α is added to the current value, and the reverse rotation is changed. When switching to the normal rotation, the current value is corrected by subtracting the correction value α from the current value. In this example, it is assumed that the No. 2 tray 3 is stopped at the detection position, and the current value at this time is 625, which is the same as the stop target value of the No. 2 tray 3, and the rotation direction of the rotary shelf 1 is reversed. Assuming that the current value is switched to the normal rotation, the current value-correction value α = 625-30 = 595, and the current value is corrected from 625 to 595. Of course, if the previous rotating rack rotating direction and the rotating rack rotating direction determined this time are the same, the above correction is not performed.

The motor 5 is activated by the next start-up operation, and the rotary shelf 1 is rotated in the rotation direction (normal rotation direction) determined as described above. In the case of this example, since the reverse rotation has been switched to the forward rotation, the rotation of the motor 5 starts at 30% as described above.
The carousel 1 starts to rotate forward with a delay of a pulse. Therefore, when the rotation of the motor 5 is started, the current value is corrected to 595 as described above, but when the rotary shelf 1 actually starts rotating, the current value is stepping up to 625 before correction, and No. 2 The position corresponds to the position when the tray 3 starts to rotate. Then, the pulse count value (current value) of the addition / subtraction counter 7 stepping with the rotation of the rotary shelf 1 (rotation of the motor 5) and the stop control position 4D = 2245 are compared and calculated,
When the current value reaches 2245, stop control is performed and the motor 5 stops. At this time, the motor 5 slides by the sliding amount Y = 20 and stops, so the current value is the stop target value = 2265 set as described above, and the No. 4 tray 3 stops at the detection position. That is, the No. 4 tray 3 stops at the position where the central position in the length direction of the plate 12 to be detected of the No. 4 tray 3 faces the detection position of the tray fixed position detector 10.

In addition, the learning value when each tray 3 passes the detection position of the pulse count value (current value) obtained by the deceleration control of the rotary shelf 1 which is rotationally driven and the addition / subtraction counter 7, that is, the absolute addresses 1B, 2A, 2B. The current value automatic correction control that automatically corrects the value of ……, or the actual stop position of the tray 3 (current value)
The stop position automatic correction control and the like in the case of deviation from the stop target value can be performed in the same manner as the conventional control method described in Japanese Patent Laid-Open No. 61-27811.

The method of determining the stop target value for each tray 3 is not limited to the method of the above embodiment. Further, in the above embodiment, the tray fixed position detector 10 was controlled to call the calling tray at the installed detection position, but when the load transfer station is set to another position with respect to the detection position, ,
The tray number to be called to the detection position is calculated from the distance (the number of trays) between the load transfer station and the detection position and the set calling tray number, and the control of the above embodiment is performed based on this result. Just go.

When the absolute addresses 1B, 2B, ... Corresponding to the reverse rotation fixed positions of the respective trays 3 are obtained from the pulse count value at the time of rising of the detection signal 14 during the reverse rotation of the rotary shelf 1, as in the conventional case, The value of the absolute address becomes smaller than the actual value (absolute address 1B, 2B ... Value obtained by the method of the above embodiment) due to the play of the transmission system when the rotary rack 1 is switched from normal rotation to reverse rotation. That is, the detector 1 of the detection target plates 12 and 13 of each tray 3
The length of the portion detected by 0 will be detected shorter than the actual length. Therefore, when calculating the stop target value from two absolute addresses A and B corresponding to the calling tray as in the example, even if the value itself is the same for forward rotation and reverse rotation, Corresponding part (Detected plate 1
(Positions above 2 and 13) are different between the forward rotation and the reverse rotation, and the stop position of the tray 3 is shifted back and forth between the forward rotation and the reverse rotation.

According to the above embodiment, however, the detected plates 12, 13 are set to the absolute address 1A, 2A ...
Since the length of the portion detected by the detector 10 is replaced with the pulse count value and the values are added to obtain the absolute addresses 1B, 2B ... Corresponding to the reverse rotation fixed positions of the trays 3, Such inconvenience does not occur.

(Operation and Effect of the Invention) As described above, according to the control method of the carousel of the present invention, when the rotation direction of the load receiving base (the tray 3 in the embodiment) is switched, the motor is actually rotated before the load receiving base is changed. A pulse count value corresponding to the amount of slip until moving is obtained in advance as a correction value, and when the rotation direction of the load receiving base switches from normal rotation to reverse rotation, the correction value is added to the current value, and reverse rotation to normal rotation is performed. Since the correction value is subtracted from the current value at the time of switching, there is a gap between the current value and the actual position of the cradle due to play in the transmission system, due to switching of the rotation direction of the cradle. Which can be prevented in advance, and is obtained by counting the pulses of the pulse transmission means (pulse encoder 6 of the embodiment) interlocked with the motor with the addition / subtraction counter. The value and the actual position of the cradle can always be accurately matched.

Therefore, because the rotation direction of the loading tray has changed,
Even if the motor is stopped in a state where the stop target value of the call receiving cradle and the current value match, the call receiving cradle may stop before a predetermined calling position due to the play of the transmission system. This eliminates the need to control the loading platform with high accuracy.

As described above, in the case where the conventional automatic current value correction control is combined and performed, it is supposed that the position of the cargo receiving platform corresponding to the current value and the actual position of the cargo receiving platform will be temporarily changed by the play of the transmission system. Even if there is a deviation, the current value is corrected to a value corresponding to the actual position of the cargo cradle by the rotation of the rotary shelf by one cargo cradle pitch or more, so that there is no problem. However, since the current value automatic correction control is not performed when calling the cargo receiving tray one ahead or one before, the calling cargo receiving tray may eventually stop before the predetermined calling position. Become. Even in such a case, according to the method of the present invention, it is possible to accurately call the one-front or one-front loading cradle to a predetermined calling position.

[Brief description of drawings]

FIG. 1 is an explanatory view of the entire structure, FIG. 2 is a front view showing a detected plate and a detector of a tray, FIG. 3 is a side view of the same, FIG. 4 is a view for explaining a detection signal, and FIG. ~ Fig. 7 is a diagram for explaining the learning method, Fig. 8 is a flow chart for explaining the control method during actual operation, and Fig. 9 is a diagram for explaining a calculation method of the target stop value and a calculation method of the stop control position. 1 ... Rotary shelf, 2 ... Drive chain, 3 ... Tray (3a ...
… Origin tray), 5 …… Rotating rack drive motor, 6 ……
Pulse encoder, 7 ... Addition / subtraction counter, 8 ...
Control computer, 10 ... Tray fixed position detector, 11
...... Origin tray detector, 12,13 ...... Detected plate, 14,14a, 1
5,15a …… Detection signal.

Claims (1)

[Claims] 1. A carousel equipped with a large number of load carriers that can be rotated in the normal and reverse directions on a circulation path, wherein the load carrier rotates in a normal direction with a pulse from a pulse transmission means interlocked with a motor for rotating the load carrier. A control method for controlling the motor so as to call the call receiving cradle to a predetermined position based on the current value obtained by adding the current load and subtracting it when the reverse rotation is performed and the stop target value corresponding to the call receiving cradle. , When the rotation direction of the loading tray is switched, a pulse count value corresponding to the slip amount from the rotation of the motor to the actual movement of the loading tray is obtained in advance as a correction value, and the rotation direction of the loading tray is positive. The correction value should be added to the current value when switching from reverse rotation to reverse rotation, and the correction value should be subtracted from the current value when switching from reverse rotation to forward rotation. The method carousels characterized by.