JP4388727B2 - Conveyor cart system - Google Patents

Description

[0001]
[Field of the Invention]
The present invention relates to a system using a carriage such as a stacker crane or a tracked carriage, and more particularly to its stop control.
[0002]
[Prior art]
In an automatic warehouse using a vertical comb rack, free-size articles can be stored. On the other hand, if the stopping accuracy of the transport carriage is not reduced to 1/2 or less of the vertical comb tooth pitch, There is a risk of interference with the slide fork of the transport carriage. In addition, since a free-sized article is stored, the stop point of the transport carriage also changes according to the size and storage position of the article, and as a result, a stop point is generated for each pitch of the vertical comb teeth. And it is difficult to stop a conveyance trolley correctly with respect to such many stop points.
[0003]
[Problems of the Invention]
A basic problem of the present invention is to enable stop control with a simple shielding plate even when there are many stop points of a transport carriage and it is necessary to increase the accuracy of the stop points.
An additional problem of the present invention is to enable accurate stopping at a stop point even when stopping from a high speed.
An additional problem in the invention of claim 2 is to provide a free-size automatic warehouse while preventing interference between the fork and the vertical comb teeth.
[0004]
[Structure of the invention]
The transport cart system of the present invention is provided with a shielding plate in which the shielding part and the non-shielding part are alternately generated with the same width W along the traveling route,
The transport carriage is provided between the first two sensors, the first two sensors including two sensors for detecting the shielding portion and the non-shielding portion of the shielding plate, and the shielding plate. The second two sensors that detect the shielding part and the non-shielding part and detect the position with respect to the stop point are arranged in a line along the traveling direction of the transport carriage, and the first two sensors The distance between the sensor in the running direction and the sensor in the running direction of the second two sensors is the distance between the sensor in the running direction behind the second two sensors and the sensor in the running direction behind the first two sensors. Position detecting means provided to be equal to the distance from the sensor ,
The first two sensors detect the position of the transport carriage with respect to the target stop point among a plurality of stop points consisting of the traveling direction center of the shielding part or the traveling direction center of the non-shielding part, and the first two sensors Since the distance between the sensors is smaller than the width W of each of the shielding part and the non-shielding part of the shielding plate, and when the transport carriage is stopped, the signals of the first two sensors are equal, so that the normal stop is achieved. Provide a means to confirm that
Furthermore, deceleration to a slow speed is started by a signal from the sensor in the traveling direction of the second two sensors, and the conveyance carriage is stopped by a signal from the sensor at the rear of the traveling direction of the second two sensors. Accordingly, a means for stopping control is provided so that the center of the position detecting means in the traveling direction coincides with the target stop point (claim 1).
[0005]
Preferably, the transport cart system is a vertical comb-type automatic warehouse, the transport cart is a stacker crane thereof, and the change between the shielded portion and the non-shielded portion is synchronized with the vertical comb teeth constituting the rack of the automated warehouse. (Claim 2 ).
[0006]
[Operation and effect of the invention]
In this invention, it is confirmed by the sensor of a position detection means whether the conveyance trolley has stopped in the correct position. Here, the first two sensors of the position detection means (at least two sensors in the embodiment, which may be referred to as stop point check sensors S1 and S2 in the embodiment) have a gap between the shielding plates. Since it is arranged narrower than the width of the part and the width W of the non-shielding part, if the sensor stops normally, both sensors should be turned on or off, and it is easy to detect whether the sensor has stopped normally. it can. For this reason, even when there are many stop points of the transport cart and it is necessary to increase the accuracy of the stop point, the stop control of the transport cart can be performed with a simple shielding plate .
[0007]
In the present invention, between the first two sensors, the second two sensors (position sensors S3 and S4 in the embodiment) for detecting the shielding portion and the non-shielding portion of the shielding plate are provided. Of the second two sensors, deceleration to the slow speed running (in the embodiment, slow speed running is referred to as creep running) is started by the signal of the sensor ahead of the running direction, and stopped by the signal of the sensor behind the running direction. Can stop at the target stop point accurately. And it is possible to confirm the position of the stop in the first two sensors. For this reason, the current position can be detected by another sensor before reaching the target stop point, and the distance from the current position detected by another sensor to the target stop point is small. Even when stopping at high speeds, it is possible to stop at the stop point accurately.
[0008]
In the invention of claim 2 , the conveying cart system is a vertical tooth type automatic warehouse, the conveying cart is its stacker crane, and is synchronized with the vertical comb teeth, preferably at the same position as the vertical comb teeth, And the non-shielding part is changed. In this way, the intermediate position between the vertical comb teeth and the vertical comb teeth can be easily set as a stop point, and the stacker crane can be stopped accurately, preventing interference between the transfer means of the stacker crane and the vertical comb teeth. it can.
[0009]
【Example】
1 to 3 show an embodiment. In these drawings, reference numeral 2 denotes a vertical comb rack, which is provided on, for example, both sides of the travel path of the stacker crane. The vertical comb teeth rack 2 is provided with the vertical comb teeth 3 at a constant pitch W, the articles are supported by a plurality of vertical comb teeth 3, and the width of the articles to be accommodated is limited within a range that can be transported by a stacker crane. Not to constitute a free size automatic warehouse. The shield plate 4 is provided in parallel with the traveling rail of the stacker crane, and the shield plate 4 is provided with the shield portion 5 and the non-shield portion 6 alternately. The shield portion 5 and the non-shield portion 6 have the same width W. ing. The change between the shielding portion 5 and the non-shielding portion 6 in the shielding plate 4 occurs at the same position as the vertical comb teeth 3 and appears in synchronization with the vertical comb teeth 3 at the same pitch as the vertical comb teeth 3.
[0010]
Reference numeral 10 denotes a travel control system of a stacker crane as a transport cart, 12 denotes a position detection unit, which includes at least two sensors, for example, detects the shielding unit 5 and the non-shielding unit 6, and the position detection unit 12 The signal is input to the stop control unit 14 and the stop point check unit 16. When the stop control unit 14 detects a change in state between the shielding unit 5 and the non-shielding unit 6 (on / off of the sensor signal), the stop control unit 14 corrects the value of the encoder used for the stop control and transports from the target stop point. The position of the carriage is obtained, and stop control such as deceleration and stop is performed. If the signals of the at least two sensors are the same at the time of stop, the stop point check unit 16 stops at the correct position. If the signals of the two sensors are different, the stop point check unit 16 determines that the stop point is defective. Output to the brake control unit 18. If the stop point is bad, the stacker crane, for example, retreats and makes a retry to stop at the correct stop point. M is a motor of a stacker crane, and B is a brake.
[0011]
FIG. 2 shows the arrangement of sensors in the position detector 12. S1 and S2 are stop point check sensors, sensors S1 and S2 are always provided, S3 and S4 are position sensors, and are provided inside stop point check sensors S1 and S2 .
[0012]
The shielding part 5 and the non-shielding part 6 both have a width W, and the interval between the stop point check sensors S1, S2 is set to be W-2D, which is slightly narrower than the interval W. The distance between the position sensors S3 and S4 is B, which is smaller than W-2D. The distance between the position sensor S3 and the stop point check sensor S1 is AD, and the distance between the position sensor S4 and the stop point check sensor S2. Is also set to AD.
[0013]
The signals from the stop point check sensors S1 and S2 are stop point check signals, which are input to the stop point check unit 16 as described above. The signals from the position sensors S3 and S4 are stop control signals, which are input to the stop control unit 14. In addition to this, signals from the stop point check sensors S1, S2 may be used for the stop control. In addition, since both the shielding part 5 and the non-shielding part 6 are W, even when the position detection part 12 faces the non-shielding part 6, the signals from the sensors S <b> 1 to S <b> 4 are not turned on / off. Is exactly the same. Therefore, the position detection unit 12 is used in the same manner when the stop control is performed so that the center of the traveling direction coincides with the center of the shielding unit 5 and when the stop control is performed so as to coincide with the center of the non-shielding unit 6. Can do.
[0014]
In FIG. 3, the waveform of the sensor signal at the time of stop control and the speed pattern of a stacker crane are shown. As described above, the vertical comb teeth of the vertical comb rack are arranged so as to face the boundary between the shielding part and the non-shielding part of the shielding plate, and here the center of the position detection part is the center of the shielding part. Suppose that the stop point is chosen to match. The sensors S1 to S4 are treated as those in which the sensor signal is turned on when facing the shielding part 5 and turned off when facing the non-shielding part, but the meaning of on / off is reversed. It is the same. Here, it is assumed that the stacker crane is traveling from right to left in FIG. 2. When the sensor S1 comes to a position where the sensor S1 faces the shielding portion where the target stop point is located, the signal of the sensor S1 is turned on. Next, the signal of the sensor S3 is turned on, and accordingly, the current position of the stacker crane with respect to the target stop point is determined and the deceleration to the creep travel is started, and then the sensor S4 is turned on to Check the position again and stop the stacker crane. It is assumed that the transport carriage has already started decelerating before the signal of sensor S3 is turned on.
[0015]
The sensors S1 and S2 are both turned on at the time of stoppage only when the stop error from the target stop point is within the interval ± D in FIG. 2, and the interval D is selected so as to be an allowable value of stop accuracy. If so, you can easily check the normal / bad stop points. When the center of the non-shielding portion is set as the target stop point, the signals of the sensors S1 and S2 should be off at the time of normal stop. As described above, the stop point check sensors S1 and S2 are sensors that use a slightly inner side of the edge of the shielding part or the non-shielding part as a target position at the time of stopping.
[0016]
In the case of an automatic warehouse using vertical comb teeth, the stop point occurs between the vertical comb teeth and the vertical comb teeth, and the required stop accuracy is high. It is difficult to correctly stop the stacker crane at such a large number of stop points. However, in the embodiment, by arranging the shielding plate 4 in which the shielding part and the non-shielding part are switched corresponding to the vertical comb teeth, the stop control can be easily performed, and the normal / defective stop point can be easily confirmed.
[0017]
In the embodiment, the position sensors S3 and S4 are used to confirm the current position immediately before the final stop point in order to accurately stop at a predetermined stop point from high speed running or medium speed running. The number of position sensors S3 and S4 may be determined according to the number of positions for checking the current position in the process of deceleration stop control .
[0018]
In the embodiment, application to an automatic warehouse system using a vertical comb rack has been shown, but the present invention can be similarly applied to, for example, a tracked cart system. Further, the signals of the position sensors S3 and S4 may be used to calculate the absolute position from the origin by integrating the number of on / off signals, but the absolute distance from the origin is detected by other methods, The position sensors S3 and S4 may be used only for stop control with respect to the target stop point. The shielding plate does not need to be provided in the entire length of the travel route of the transport carriage such as a stacker crane, and may be provided only near the stop point.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a stop control system of a stacker crane with respect to a vertical comb rack in an embodiment. FIG. 2 is a diagram showing detection of a shielding plate and signal generation in the embodiment. The waveform diagram during the stop control in the embodiment, (1) shows the sensor signal, (2) shows the speed pattern.
[Explanation of symbols]
2 Vertical Comb Rack 3 Vertical Comb 4 Shielding Plate 5 Shielding Unit 6 Non-shielding Unit 10 Stacker Crane Travel Control System 12 Position Detection Unit 14 Stop Control Unit 16 Stop Point Check Unit 18 Motor / Brake Control Unit M Motor B Brake S1 , S2 Stop point check sensor S3, S4 Position sensor

Claims (2)

Along the travel path, a shielding plate is provided in which the shielding portion and the non-shielding portion are each formed with the same width W and alternately,
The transport carriage is provided between the first two sensors, the first two sensors including two sensors for detecting the shielding portion and the non-shielding portion of the shielding plate, and the shielding plate. The second two sensors that detect the shielding part and the non-shielding part and detect the position with respect to the stop point are arranged in a line along the traveling direction of the transport carriage, and the first two sensors The distance between the sensor in the running direction and the sensor in the running direction of the second two sensors is the distance between the sensor in the running direction behind the second two sensors and the sensor in the running direction behind the first two sensors. Position detecting means provided to be equal to the distance from the sensor ,
The first two sensors detect the position of the transport carriage with respect to the target stop point among a plurality of stop points consisting of the traveling direction center of the shielding part or the traveling direction center of the non-shielding part, and the first two sensors Since the distance between the sensors is smaller than the width W of each of the shielding part and the non-shielding part of the shielding plate, and when the transport carriage is stopped, the signals of the first two sensors are equal, so that the normal stop is achieved. Provide a means to confirm that
Furthermore, deceleration to a slow speed is started by a signal from the sensor in the traveling direction of the second two sensors, and the conveyance carriage is stopped by a signal from the sensor at the rear of the traveling direction of the second two sensors. Accordingly, a transport cart system provided with means for controlling the stop so that the center of the position detection means in the traveling direction coincides with the target stop point. The transport cart system is a vertical comb-type automatic warehouse, the transport cart is its stacker crane, and the change between the shielded portion and the non-shielded portion occurs in synchronization with the vertical comb teeth constituting the rack of the automatic warehouse. The conveying cart system according to claim 1 , wherein

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