JPH07117851B2 - Carrier allocation method - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method of configuring a transfer control function in a factory automation (FA), and is particularly suitable for a plurality of automatic guided vehicles in response to a transfer request. The present invention relates to a method of configuring a transport vehicle group control function suitable for control of allocating various empty transport vehicles.

[Background of the Invention]

In order to facilitate understanding of the present invention, before describing the background of the present invention, a target of transport control, a purpose, and a function of allocating an empty transport vehicle to a transport request will be described with reference to FIG.

The layout in the figure is often adopted in the factories automation system. Work place (cell) consisting of processing machine or assembly machine and peripheral equipment
Several 101 are installed. Products in their workplace 101
Will be completed after several steps. The objects are transferred between the work areas 101 by a transfer vehicle 103 whose track 102 can be easily changed. The place for delivering goods between the carrier 103 and the workplace 101 is
An input buffer 104 and an output buffer 105 connected to the work place 101.

The purpose of the transfer control is to transfer the products to each worksite 101 in a timely manner so as to improve the operation rate of the entire worksite 101 in order to maximize the production amount per unit time.

A function that plays an important role as a transport control function that achieves the above-mentioned purpose is a function for assigning an empty transport vehicle to a transport request.
Is 6. This function is
An appropriate empty carrier is assigned to a carrier in the tracking table 108 grasped by the tracking function 107 and a carrier request generated based on the current state of the work place. The allocation results are three, that is, “conveyance source” and “conveyance destination” of the object to be conveyed, and “number machine” of the conveyance vehicle to which the conveyance work is allocated. When this result is transmitted to the on-board control device mounted on the transport vehicle, the control device guides the transport vehicle to the transport source and the transport destination to instruct the unloading work.

Next, the background of the present invention will be described.

Conventionally, vacant carrier allocation control software has been newly developed individually for each customer. There are two reasons for this. One is that the condition of whether or not the object to be transferred from the work place can be transferred differs for each customer. This is because the condition depends on the equipment configuration of the workplace.

The second reason is various evaluation items. There are various items to evaluate a workplace where no work is likely to occur. Also,
Some evaluation items from other aspects, such as giving priority to goods output over goods receipt, must also be considered. These vary from customer to customer and are unique to a particular customer that cannot be mentioned in advance, which makes standardization difficult.

From the above, as a problem, the software development cost is large,
There are problems that system startup and modification period are large and it is difficult to develop the system step by step.

It should be noted that in the prior application relating to the carrier vehicle, the one to solve the above problems is to be positioned at the lower level as the control level, to be related to the guide system of the dolly alone, and to be positioned a little higher than that. , There is an optimal route selection method (Japanese Patent Application No. 57-76338). However, these do not relate to the operation management of the vehicle group that is the most difficult to standardize and that most affects the transportation efficiency, which is the object of the present invention.

[Object of the Invention]

The object of the present invention is to solve the problems of the conventional method, to consider the conditions and evaluation items peculiar to the customer, and also to reduce the software development cost, start up the system, shorten the change period, and gradually develop the system. It is an object of the present invention to provide a method of configuring a function of allocating an empty vehicle to a transportation request, which realizes the possibility of the above.

[Outline of Invention]

 The outline of the invention will be described with reference to FIG.

If we consider the problem of allocating vacant vehicles to the transfer request as a resource allocation problem (Fig. 2 (A)), the transfer request as a job
This is a problem in which 201 is assigned (allocated) to a carrier 203 as a resource in consideration of some evaluation items 202. In order that the allocation algorithm 204 can be standardized, the input transport request and transport vehicle related information can be defined only by some predetermined concepts, and the number of evaluation items at the time of assignment is basically one. Is. Therefore, it is considered whether or not the above conditions are satisfied for each of them. (Less than,
See FIG. 2 (B). ) First, regarding the information related to the carrier, the track layout and the condition of the carrier (transfer work in progress, current position) are the main ones. For example, in the track layout, various tracks are defined by nodes and directed arcs. Satisfies the standardization conditions such as possible.

Next, the transport request does not satisfy the standardization condition because there are customer-specific conditions that cannot be predicted in advance. Therefore, the raw transfer request 201 is not directly input to the allocation algorithm, but it is processed for each customer and converted into a common transfer request to satisfy the standardization condition of the allocation algorithm. As the common transport request, {transport source, transport destination, priority} 205 is set. Here, the priority is a value indicating the urgency of the transportation with respect to the transportation request.

Next, considering the evaluation items, most of the evaluation items are related to the transport request, and they can be summarized in the priorities described above. Therefore, if the transport request is processed up to the form of {transport source, transport destination, priority}, the access time is minimized 207 in sequence from the transport request with the higher priority.
It is sufficient to assign a carrier under one evaluation item.

From the above discussion, it becomes possible to standardize the transport vehicle allocation algorithm 206 to the transport candidates that are prioritized.

Next, a standardization consideration will be given to the processing 208 of the transport request from the “raw transport request” to the “prioritized transport request”.

Some of the evaluation items are used quite frequently. If these priority calculation modules are created in advance, the amount of software development will be reduced. However, since the raw transportation request includes the condition unique to the customer, under such a condition, the priority calculation module needs to be easily incorporated in the processing 208 of the transportation request for each customer. In addition, it is necessary to easily incorporate a priority calculation module for customer-specific evaluation items (this is created for each customer).

In order to realize this, the processing 208 for processing the transport request is divided into two stages. In the first stage, with respect to the transport request 201, extraction 210 of transport candidates is performed based on a transport availability condition 209 that is a condition of transport availability. Specifies the format of this result,
Let's say {transport source, transport destination} 211. In the second stage, for the {transport source, transport destination} 211, a transport candidate prioritization process 212 is performed in which priority is calculated in consideration of each evaluation item. The format of this result is the allocation algorithm 206 described above.
Is input {conveyance source, conveyance destination, priority} 205.
The priority is defined as the weighted sum of the priorities of the evaluation items.

If the division is performed as described above, the prioritization process of the transport candidates 21
Since the input and output formats of 2 are specified, the priority calculation module that can be created in advance or the customer-specific priority calculation module that is newly created for customer correspondence is included in the processing 208 of the transport request for each customer. It can be easily incorporated.

The process of calculating the weighted sum of the priority of each evaluation item can be standardized if the priority and weight of each evaluation item are given.

Example of Invention

An embodiment of the present invention will be described below with reference to FIGS. 3 to 5.

FIG. 3 shows the relationship between the function block and the table in the present invention. The general flow of processing is to extract transport candidates,
Next, prioritize the transport candidates (corresponding to the above {transport source, transport destination}), and finally, the transport vehicles to the prioritized transport candidates (corresponding to the above {transport source, transport destination, transport rate}). Is assigned, and will be described in this order.

(1) Extraction of Transport Candidates This processing unit must be created for each customer, because the transport availability condition is unique to the customer. Although the contents of this processing are not the claims of the present invention, the outline of the processing will be described below.

The transport candidate extraction unit 301 (i) finds a delivery buffer (transport source) having an item to be delivered, and (ii) next, based on the buffer and the item on the buffer, the process route table 302. Then, the carrying-in buffer 104 of the work place where the article is to be carried next is obtained. (Iii) Next, whether the corresponding carrying source can be carried out and the carrying destination can be carried in and the carrying availability condition table 303 If it is possible to carry out and carry in by referring to the tracking table 108, the corresponding {transport source, transport destination} 211 is registered in the transport candidate table 304 as a transport candidate.

In the above extraction of the transportation candidates, the one that can be standardized is only the process route table 302 (this table shows, for each item, the name of the work place that must be reached until the product is completed in the order of work. ing).

(2) Prioritization of Transport Candidates This process is performed for each transport candidate {transport source, obtained in (1).
Priority P is calculated for the transport destination} 304, and {transport source, transport destination, priority} is written in the prioritized transport candidate table 305.

If the priority for each evaluation item is Pi and its weight is αi, P is calculated by the following formula.

In order to increase the standardization degree and to facilitate addition of modules, the process of obtaining P, the process of obtaining each Pi,
It is divided into the process of obtaining P based on Pi.

As the calculation module of Pi, for the frequently used one, a standard module 306 and a priority constant table 307 necessary for the calculation are prepared in advance, and the customer specifies and uses the necessary one. On the other hand, for the customer-specific Pi, the priority calculation module 308 and its priority constant table 309 are created each time.

Next, the transport candidate total priority calculation unit 310, which is a standard module for obtaining P based on Pi, will be described.
Before describing the processing flow, about the points of processing,
First, it explains.

[Point 1] The evaluation items include those in which the priority is determined only by the attribute of the conveyed product (called type I) and those in which the priority is determined by the surrounding physical distribution situation (called type D). Type I
For example, "Issuance is preferred over receipt". in this case,
If the transportation candidate is a delivery, for example, 5 points;
The point is given, and the priority is uniquely determined only by the attribute of the conveyed product. Therefore, the priority of Type I need only be calculated once for each transportation candidate.

As an example of the type D evaluation scale, there is “the sum of the number of items on the carry-in conveyor and the number of items confirmed to be conveyed to the conveyer”. This evaluation item is often adopted because the smaller the number, the sooner the objects to be assembled and processed disappear, and the higher the possibility that the corresponding processing machine will play. An item whose transfer has been confirmed corresponds to a transfer candidate whose priority has been finally determined, and when one of the transfer candidates is determined, the surrounding physical distribution status (in this example, the number of items whose transfer has been confirmed to be transferred) changes. The prioritization of transport requests is sequentially decided one by one, and the calculation of type D must be calculated in each new distribution situation.

[Point 2] A plurality of destinations, for example, when there are a plurality of the same processing machines or assembling machines, a plurality of possible destinations are considered for one conveyed product. Which of the transport destinations should be transported may be determined as a transport destination having a high transport priority.

To easily perform this process, the transport candidate extraction unit 301
Then, for one such transported object, the transport source is the same,
As a transfer destination, a transfer request paired with a plurality of transfer destinations is created. In the transport candidate total priority calculation unit 310, when the priority of one of these transport candidates is determined, the remaining transport candidates may be excluded from the priority determination targets.

[Point 3] Since there is a D type evaluation item, the priority P of each transport candidate is calculated, and the transport candidate having the highest priority is determined one by one. At this time, it is necessary to reduce the number of spare areas of the carry-in buffer of the transport destination whose priority is determined by one. If the number of buffer margin areas becomes zero, the transport candidate having the transport destination and the priority of which is undetermined is excluded from the priority determination target.

Next, the calculation flow of the total priority calculation unit 310 of the transportation candidates will be described with reference to FIGS. 4 and 5.

First, the priority calculation table (see FIG. 5; corresponding to 311 in FIG. 3) is initialized (block 401).

(I) In-group priority determination number k ← 0.

The group means a group of transportation candidates having the same transportation destination. When k = 0, the priority P of the corresponding transport candidate
Is a parameter that has not been determined, and if k ≠ 0, it is a parameter indicating that the priority is determined kth in the group (used when recalculating the priority of the D type evaluation item described in point 1 above). .

(Ii) Priority determination target exclusion flag f ← 0.

This is a flag used when handling the case described in points 2 and 3. When f = 1, the corresponding transport candidate is excluded from the priority determination target.

(Iii) Number of spare areas available ← Current status.

This is used in the case described in point 3.

Next, for each transport candidate, the priority Pi of the evaluation item with call designation is calculated, and from this and the weighting coefficient αi, the total priority is calculated. (Block 402).

The call designation flag is a flag that is used in the priority calculation module prepared in advance or a priority module created uniquely to the customer, and when 1 is designated, the call is designated (see FIG. 5). .

The above call designation, weight, type of evaluation item, and evaluation item name (corresponding to the subroutine name) are defined off-line in advance by the constant setting unit 312 in FIG.

-The values of Pi and P calculated in this block are stored in the priority calculation table (Fig. 5) for use in subsequent processing.

Next, referring to the priority calculation table, the total priority P is the maximum among the transport candidates whose priority has not been determined (k = 0) and which has not been excluded from the priority determination target (f = 0). Find things. The transport source is X * and the transport destination is y * (block 403).

Next, an intra-group priority determination number is assigned to the transport candidate {x *, y *} (block 404). With this, the priority P of this transport candidate is determined.

Next, if there is a transport candidate whose transport source is x * and whose transport destination is not y * and k = 0 and f = 0, then f is set to 1. (Block 405).

This process is the process of point 2 described above.

Next, it is assumed that the transport candidate {x *, y *} has been loaded into the transport destination y *, and 1 is subtracted from the number of buffer margin areas of the transport destination y * (box 406).

This process is the process of point 3 described above.

Next, the transfer destination is y * and the priority is not determined (k = 0)
Then, it is checked whether or not there is a transport candidate that has not been excluded from the priority determination targets (f = 0) (block 407). After that,
Divided into 3 routes.

[Route 1] If there is no transport candidate, check whether all transport candidates have been processed (block 408),
If completed (k ≠ 0 orf = 1 for all transport candidates),
The process ends. If not complete, return to Box 403.

[Route 2] If there is a transport candidate checked in box 407, and the number of buffer margin areas at the transport destination y * is not zero (determined in block 409), the D type priority is set as the processing of point 1 above. To recalculate. At this time, P is also recalculated (block 410). And block 403
Return to.

[Route 3] If there is a transport candidate checked in the box 407 and the number of buffer margin areas of the transport destination y * is zero (determined in block 409), the transport candidate is selected as the process of point 3 described above. Exclude from priority determination (f ←
1. Block 411). Then go to Block 408.

(3) Allocating empty transport vehicles to the priority-assigned transport candidates Here, the priority-assigned transport candidates {transport source, transport destination, priority} determined in (2) Sequentially, an empty transport vehicle having the minimum sum of the travel time to the transport source and the travel time to the transport destination is assigned to the relevant transport candidate. The allocation is performed by the vehicle allocation unit 313 for the prioritized transportation candidates, the track layout related tables 314, 3
15, 316, the carrier attribute table 317, and the tables 318 and 319 necessary for the access time calculation, and the tracking table 108, to carry out. This assignment algorithm is omitted because it can be standardized and is not the claim point of the present invention, as described in the summary of the invention.

Although the above-mentioned embodiment is intended for a carrier vehicle, the present invention is
As can be seen from the functional block diagram of FIG. 3, it can be applied to the control software of a general carrier such as a crane.

According to the embodiment shown in FIG. 3, it becomes easy to add a priority calculation module for a customer-specific transportability condition and a customer-specific evaluation item, and the priority calculation module for frequently used evaluation items is set as a standard module. To be able to prepare in advance, to be able to standardize the total priority calculation part of transport candidates, and to be able to standardize an empty transport vehicle allocation algorithm for transport requests (processed into common transport requests) Therefore, the effects of reducing the development cost of the transfer control software, starting up the transfer system, shortening the change period, enabling stepwise development of the transfer system, and improving the quality of the transfer control software can be obtained.

In the above embodiment, it is premised that the transport candidate extraction unit 301 and the priority calculation module that must be created for each customer are created in a procedural language. Use “IF (condition), THEN
(Conclusion) A rule-based control method in which a program can be created if it is described as it is with a "type rule" may be applied.
(For this rule type control system, see Japanese Patent Application No. 58-077985.
No.). This further facilitates addition and modification of logic.

In the above-mentioned embodiment, the processing 208 of the transportation request is divided into the transportation candidate extraction 210 and the transportation candidate prioritization 212.
In a system with few evaluation items, it is not necessary to divide.

〔The invention's effect〕

As described above, according to the present invention, the handling of the transport request is divided into two stages, that is, in the first stage, the transport request is extracted based on the transport availability condition with respect to the transport request. The result is expressed by {combination of transport source and transport destination}. In the second stage, priority processing of transport candidates is performed on {combination of transport source and transport destination} in consideration of each evaluation item, and the priority is calculated. It is expressed as {combination of transport source, transport destination, and priority} in association with the combination with transport destination} and is input to the allocation algorithm.

In this way, by dividing the transport candidate extraction process and the transport candidate prioritization process, the input and output of the transport candidate prioritization process can be defined regardless of the use, user conditions, and the like. Therefore, a priority calculation module that can be created in advance or a customer-specific priority calculation module that is newly created to correspond to a customer can be easily incorporated in the transport request for each customer. That is, it becomes easier to add a priority calculation module for customer-specific transport availability conditions and customer-specific evaluation items, and it becomes possible to prepare in advance a priority calculation module for frequently used evaluation items as a standard module. Since it becomes possible to standardize an empty vehicle allocation algorithm for transport requests (processed into common transport requests), (1) reduction of development cost of transport control software (2) establishment of transport system (3) Enabling the stepwise development of the transfer system (4) The effect of improving the quality of the transfer control software can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram relating to a typical layout of a transport system and a function for controlling the allocation of empty vehicles to a transport request, FIG. 2 is a schematic explanatory diagram of the present invention, and FIG. FIG. 4 and FIG. 4 are the processing flow charts of the total priority calculation unit of the transportation candidate, which is one of the functions of the present invention, and FIG.
The figure is a diagram showing a priority calculation table used in the processing. 101 …… Workplace, 102 …… Track, 103 …… Transport vehicle, 104 ……
Carry-in buffer, 105 …… Carry-out buffer, 106 …… Control function for assigning vacant vehicles to the transfer request, 107 …… Tracking function, 108 …… Tracking table, 201 …… Transfer request,
202 ... Evaluation item, 203 ... Transport vehicle, 204 ... Transport vehicle allocation algorithm for transport request, 205 ... {Transport source, transport destination, priority}, 206 ... Transport vehicle to prioritized transport candidate Allocation algorithm, 207 ... Minimizing access time, 208 ...
… Processing processing of transport request, 301 …… Transport candidate extraction unit, 302
…… Process route table, 303 …… Conveyance permission / prohibition condition table, 304 …… Conveyance candidate table, 305 …… Priority transfer candidate table, 310 …… Transport candidate total priority calculation unit, 311 …… Priority calculation table , 313 ... Transport vehicle allocating unit for transport candidates with prioritization.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Okasaka 794 Higashitoyoi, Shimomatsu City, Yamaguchi Prefecture Inside the Kasado Plant, Hiritsu Manufacturing Co., Ltd. (56) References JP-A-61-21508 (JP, A) JP-A-SHO 58-17008 (JP, A) JP-A-60-197354 (JP, A) JP-A-60-251409 (JP, A)

Claims (3)

[Claims] 1. A plurality of carry-out ends and a carry-in end are connected by a predetermined transport route, and a plurality of transport vehicles arranged on the transport route are assigned according to a transport source, a transport destination, and a priority situation. In the allocation method using a computer to do, first select a transport request that is acceptable as a transport candidate according to the transport availability condition for the combination of the transport source and the transport destination, and select the transport format as {transport source and transport destination Combination), and store them in the storage device of the computer, and then prioritize those that are allowed and stored as transport candidates according to predetermined priority conditions. As an output format of this, {transport source, transport destination and priority Combination vehicle, and stores it in the storage device of the computer, and assigns the vehicle from the stored one having the highest priority. 2. A condition for allocating a carrier to a vehicle having a high priority is that the sum of the time required for the carrier to move to the carrier and the time required to move the carrier to the destination is minimized. A method of allocating a carrier according to claim 1. 3. The scope of claim 1 or 2, wherein one of the priority conditions with respect to those allowed as the transportation candidates depends on a condition as to whether or not the transported objects are dependent on the loading order. The method for allocating a carrier according to item 2.