JP2005306570A - Conveyance system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conveyance system improving conveyance efficiency. <P>SOLUTION: A host CPU allots commands to first and second cranes, and each of the cranes communicates information of its position, speed, destination, condition, etc. with the other. Each of the cranes regulates its own position and speed in order to avoid an interference by judging existence of the interference with the other cranes in its travelling to the destination and in accordance with its own and the other's positions, speeds, destinations, conditions, etc. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transport system in which transport carts such as a stacker crane, a tracked cart, an overhead traveling vehicle, and a traverser are reciprocated on the same travel rail.

  There is an example in which a long automatic warehouse is provided for a clean room or the like, the travel distance of the stacker crane becomes long, and two or three stacker cranes are driven on the same travel rail in terms of transport efficiency. In such a case, the traveling rail is divided into a dedicated area assigned to one stacker crane and a common area where each stacker crane can travel, and the approach to the common area is limited to one stacker crane. It has been known. However, if it does in this way, in order to convey articles | goods from the exclusive area of one stacker crane to the exclusive area of another stacker crane, transshipment is needed on the way. In addition, when a large amount of conveyance command is generated in one dedicated area, only one stacker crane can execute the conveyance command.

  Therefore, it is conceivable to block the section including the start point (From position) and the end point (To position) of the transport command from the current position of each stacker crane so that other stacker cranes cannot enter. However, in this case, a considerably wide section is blocked for one stacker crane, and the traveling of other stacker cranes is hindered.

An object of the present invention is to improve the conveyance efficiency by making it possible to prevent the interference between the conveyance carriages by a method other than the section block.
Another object of the present invention is to reduce the burden on the host controller by allowing the carriage to autonomously process the presence or absence of interference between the carriages.
An additional problem in the invention of claim 3 is to provide a specific configuration for determining the presence or absence of interference between transport carts.

  The transport system of the present invention is a system in which a plurality of transport carts reciprocate on the same traveling rail, and a controller that controls the plurality of transport carts is configured to transfer the transport carts from at least the position of each transport cart and the travel destination. The present invention is characterized in that interference prediction means for predicting the presence / absence of interference and interference avoidance means for restricting travel of one of the transport carriages are provided so as to avoid interference predicted by the interference prediction means.

  The transport system of the present invention is also a system in which a plurality of transport carts reciprocate on the same traveling rail, and the transport cart is further moved from the position of the own machine and other transport carts to the travel destination. An interference predicting means for predicting the presence or absence of interference with a carriage and an interference avoiding means for restricting the travel of the own machine or another transport carriage so as to avoid the interference predicted by the interference predicting means are provided. .

  Preferably, the interference prediction means obtains the traveling direction from the position of each transport carriage and the destination of the traveling.

  In the present invention, the presence or absence of interference is predicted from the position of the transport carriage and the destination of travel, and interference avoidance processing such as limiting the speed, waiting, or retracting is performed. For this reason, it is not necessary to block a wide range from the current position to the end point of the transport command for one transport cart, and if there is no interference between the transport carts even at close positions, the transport command can be executed in parallel. The transport efficiency is improved (claims 1 to 3).

  Further, in the invention of claim 2, since the transport carriage can autonomously determine the presence or absence of interference, the host controller can assign a transport command without considering the presence or absence of interference, for example, and the burden on the host controller is reduced. It is reduced. Particularly preferably, the transporting carriage is provided with communication means between the carriages so that information such as position and travel destination can be communicated with each other.

  In the invention of claim 3, the traveling direction is obtained from the position of the transport carriage, for example, the current position and the travel destination, for example, the From position and the To position in the transport command. As a result, it is possible to determine whether the inter-vehicle distance between the transport carriages is shortened or lengthened, and whether the relative speed is high or low, and it is possible to accurately predict the presence or absence of interference, thereby further improving the transport efficiency. .

  In the following, an optimum embodiment for carrying out the present invention will be shown.

  1 to 4 show an example of a stacker crane used for an automatic warehouse, but the same applies to other transport carts. In the figure, reference numeral 2 denotes an upper control processing unit (upper CPU) which manages the entire conveying system. Reference numerals 4 and 6 denote a pair of stacker cranes, for example, but three or more stacker cranes may be used. The stacker cranes 4 and 6 reciprocate along a common traveling rail 8, and the length of the traveling rail 8 is, for example, about 100 to 300 m. The stacker cranes 4 and 6 are provided with a lifting platform 10 provided with transfer means, and a position sensor 12 such as a laser distance meter, and the distance from the reflector 14 is measured. Measure the position. In the position measurement, a plurality of marks are provided along the traveling rail 8, the position is calibrated by detecting the marks, and the number of rotations of the traveling wheels of the stacker cranes 4 and 6 is an encoder between the marks. May be read and interpolated. The stacker cranes 4 and 6 are provided with a collision prevention sensor 13 to measure the distance between them. The collision of the stacker cranes 4 and 6 can be prevented by the collision prevention sensor 13, but if only the collision prevention sensor 13 is used, sudden braking is repeated. Therefore, traveling is restricted so that interference between the stacker cranes 4 and 6 does not occur and the maximum conveyance efficiency is obtained, and the collision prevention sensor 13 is used as fail-safe.

  For example, a rack 16 is provided along the traveling rail 8 and a processing equipment 18 is provided on the opposite surface of the rack 16. The stacker cranes 4 and 6 are disposed between the rack 16 and the station 20 and a load port 22 provided in the processing equipment. Transports articles such as semiconductor cassettes and liquid crystal substrates. The transport command from the host CPU to the stacker cranes 4 and 6 is given as a transport command from the transport base point (From position) to the transport end point (To position), and the host CPU 2 sends a transport command to each stacker crane 4 and 6. This is called the assignment of the conveyance command.

  FIG. 2 shows the control system of the stacker cranes 4 and 6 and the configuration of the host CPU 2. The constructions of the stacker cranes 4 and 6 are the same. The travel control unit 30 controls a travel motor (not shown) to run, and the lift control unit 32 controls the lift motor (not shown) to raise and lower the lift platform. The transfer device such as a slide fork or a SCARA arm is controlled by 34 to transfer the article. The station communication unit 36 communicates with a rack station or a load port of a processing facility before transferring an article, and arranges a transfer procedure. The position sensor 12 obtains the absolute position of the stacker cranes 4 and 6 and is used for travel control in the travel control unit 30.

  The communication unit 38 communicates between the stacker cranes 4 and 6 and between the stacker cranes 4 and 6 and the host CPU 2 by infrared communication, communication using the traveling rail 8, or communication using a power supply line (not shown). Do. The communication unit 38 may be a separate communication unit for communication between the stacker cranes 4 and 6 and for communication between the stacker cranes 4 and 6 and the host CPU 2. The storage unit 40 stores data necessary for conveying articles on the stacker cranes 4 and 6 and data necessary for preventing interference. The data necessary for the conveyance of the article includes the current position and conveyance command of the own machine, the speed, acceleration, traveling direction of the own machine, a state such as stoppage during transfer, transfer, and occurrence of an abnormality. As data for preventing interference, there are the current position, speed, traveling direction, acceleration, the From position and To position of the conveyance command, and the status such as stop, transfer, abnormality occurrence, etc. during standby. The traveling control unit 30 generates a speed pattern for traveling from the current position of the stacker crane to the From position, or traveling from the From position to the To position. A travel speed pattern from the To position to the From position and a travel speed pattern from the From position to the To position can be generated.

  The interference prediction unit 42 predicts the presence or absence of interference between the stacker cranes 4 and 6. For this purpose, in the embodiment, data on the destination of travel is used. For example, when traveling from the current position to the From position of the transport command, the From position is the destination. When traveling from the From position to the To position, the To position is the destination of the travel. The presence or absence of interference is predicted at least in the range up to the destination of travel. Even if there is no interference when traveling to the From position, interference may occur when traveling to the To position after that. In this case, predict whether or not there is interference when traveling from the From position to the To position. It is optional.

  There are various methods for predicting the presence or absence of interference, but what is required is the current position of the own aircraft and the other aircraft and the destination of travel. For example, if the travel section from the current position to the destination of travel is more than the distance between the trucks necessary for preventing interference between the own machine and the other machine, no interference occurs. Even if the traveling sections overlap, if traveling in the same direction, interference will occur if the trailing stacker crane regulates the speed and position so that a sufficient distance between the trucks can be obtained with the preceding stacker crane. Can be avoided. Even when two stacker cranes travel in opposite directions and the travel destinations cross, interference can be avoided if one stacker crane delays travel. Therefore, as a basic method for predicting interference, the current position of the two stacker cranes and the destination of travel are compared to determine the presence or absence of interference. Avoid interference.

  Alternatively, the speed pattern or position pattern of the own aircraft and other aircraft may be predicted from the current position and the destination of travel, and the presence or absence of interference may be determined based on this prediction. This method can be said to determine the presence or absence of interference by simulating travel to the travel destination for the own aircraft and other aircraft. Since the simulation is ambiguous, it is preferable to determine that interference occurs unless the interference does not occur reliably. Then, when it is predicted that interference will occur, processing such as position or speed restriction or retreat is performed so as to avoid interference, as described above.

  In a method that emphasizes communication between stacker cranes, the stacker cranes communicate and store information such as speed, acceleration, and current state in addition to the current position and the destination of travel, for example, at predetermined time intervals. . Then, more accurate prediction is performed while correcting the simulation result with the latest information of other devices obtained by communication. In this case as well, there is no change in performing avoidance so as to avoid interference.

  44 is an avoidance unit, and when the interference is predicted by the interference prediction unit 42, processing such as delaying the activation of the stacker crane, limiting the speed, and retreating is performed to avoid the interference. Note that which stacker crane is to be avoided is avoided, for example, if a transport command is assigned later, or a stacker crane that assigns priority to the transport command and executes a transport command with a lower priority. Rules are established. In addition, a standby stacker crane to which no transfer command is assigned is retracted to the nearest point within a range where interference does not occur, when avoidance is requested from the stacker crane that is executing the transfer command.

  The host CPU 2 is provided with a communication unit 50 to communicate with the communication unit 38 of the stacker cranes 4 and 6, and the conveyance command management unit 52 assigns the conveyance command to the stacker cranes 4 and 6 and receives the execution result of the conveyance command. The execution status of the conveyance command is managed. The crane state storage unit 54 stores the current position, speed, acceleration, stopping, transferring, and abnormal states of the stacker cranes 4 and 6. The interference prediction unit 56 and the avoidance unit 58 may not be provided in the upper CPU 2, but here, these are provided in the upper CPU. In the embodiment, the stacker cranes 4 and 6 autonomously determine the presence or absence of interference and avoid it. However, the interference prediction unit 56 of the host CPU 2 determines the presence or absence of interference, and the avoidance unit 58 changes the stacker crane to the stacker crane. You may make it command avoidance. The interference prediction method and the avoidance method are the same as those of the interference prediction unit 42 and the avoidance unit 44 mounted on the stacker crane. Furthermore, although the upper CPU 2 is provided with a monitor 60 and a keyboard 62, a touch panel may be provided instead.

  FIG. 3 shows processing related to prediction and avoidance of interference. Here, in addition to the current location of the aircraft and the other aircraft and the destination of travel, the speed, acceleration, state, etc. will be described as communicating at predetermined time intervals, but only the current location and the destination of travel will be used. The processing that was done may be used. FIG. 3 a) shows a case where the traveling direction is the same, and since the destination of the own aircraft and the destination of the other aircraft do not cross, it is not necessary for the preceding other aircraft to evacuate. In this case, a restriction is imposed on the position and speed of the succeeding own machine so that the necessary distance between the trucks can be maintained between the other machine. The upper right side of a) shows the minimum distance between the bogies in the three cases of high speed, low speed, and fine speed.

  In FIG. 3b), since the traveling direction is opposite and the destination is crossed, it is necessary to evacuate or wait. In this case, which stacker crane is to be retracted is determined according to predetermined rules such as the order in which the transport command is assigned and the priority of the transport command, and the stacker crane on the retract side is subject to interference from the destination of the other machine. Travel to a position where it does not occur and wait until the other aircraft moves from the destination.

  FIG. 3 c) shows an example in which the traveling direction is reversed and the destination also crosses, but the evacuation is unnecessary because the time predicted to reach the destination is far away. In this case, the other aircraft side regulates the traveling speed and the like so that it does not interfere until the aircraft arrives at the destination and departs.

  FIG. 3 d) shows a case where the own machine is executing a transfer command and the other machine is stopped without being assigned a transfer command. In this case, the destination of the aircraft is far from the current position of the other aircraft, and the other aircraft needs to be evacuated.The other machine is requested to evacuate by communication between stacker cranes, and the other machine is assigned a transport command. Because there is no, evacuate according to the request.

  FIG. 4 shows an interference prevention algorithm in the embodiment. The host CPU assigns a conveyance command to crane No. 1 and crane No. 2, and each stacker crane disassembles it into a run from the current position to the From position and a run from the From position to the To position. . Each stacker crane communicates information on the current position, speed, acceleration, state, and travel destination of the other stacker crane at predetermined time intervals to determine the presence or absence of interference. If there is interference, avoidance is performed according to a predetermined rule, and if there is no interference, the conveyance command is executed as it is.

In the embodiment, the following effects can be obtained.
(1) Interference can be avoided autonomously by communication between stacker cranes.
(2) In order to avoid interference, the waiting time can be shortened and the evacuation distance can be minimized compared to the case where the entire travel section is blocked.
(3) The waiting and evacuation of the stacker crane can be minimized.

Block diagram of the transport system of the embodiment The block diagram which shows the control system of the conveyance system of an Example The processing relating to interference in the transport system of the embodiment is schematically shown. A) shows the example in which the traveling direction is the same, and interference can be avoided by imposing speed and position restrictions on the aircraft, and b) the traveling direction. Since the destination interferes with the opposite destination, the aircraft or the other aircraft waits.c) shows an example where the traveling direction is opposite and the destination interferes, but the distance between the carriages is large, so interference can be avoided. And d) shows an example in which the other device is withdrawn in order to avoid interference with the other device that is stopped. The flowchart which shows the control algorithm of the conveyance system of an Example

Explanation of symbols

2 Host control processing unit (host CPU)
4,6 Stacker crane 8 Traveling rail 10 Lift platform 12 Position sensor 13 Collision prevention sensor 14 Reflector 16 Rack 18 Processing equipment 20 Station 22 Load port 30 Travel control unit 32 Elevation control unit 34 Transfer control unit 36 Station communication unit 38 Communication Unit 40 storage unit 42 interference prediction unit 44 avoidance unit 50 communication unit 52 transport command management unit 54 crane state storage unit 56 interference prediction unit 58 avoidance unit 60 monitor 62 keyboard

Claims (3)

In a system in which multiple carriages reciprocate on the same traveling rail,
The controller for controlling the plurality of transport carts is configured to predict interference between the transport carts based on at least a position of each transport cart and a travel destination, and to avoid interference predicted by the interference predictor. And an interference avoidance means for restricting the travel of any of the transport carts. In a system in which multiple carriages reciprocate on the same traveling rail,
Interference predicting means for predicting the presence or absence of interference with the other transport carriage from at least the position of the own machine and the other transport carriage and the travel destination on the transport carriage, and avoiding the interference predicted by the interference prediction means. As described above, a conveyance system comprising interference avoiding means for restricting travel of the own machine or another conveyance carriage. The transport system according to claim 1 or 2, wherein the interference prediction means obtains a travel direction from a position of each transport carriage and a travel destination.

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