JPH04115858A - Device and method for scheduling production system - Google Patents

Abstract

PURPOSE:To greatly improve a production efficiency, by terminating work only with the work machine of a short tact time so that there is no work suspension by this work machine, even in case of translating to the operation schedule of the next time from that of this time. CONSTITUTION:When a work termination signal is transmitted from the counting part for a work machine of a work machine 10, it is decided as to whether or not the time necessary for the work termination on the work of the unworked part in the works under working presently is shorter than the set time. In the case of the decision result being YES the process preparing a 2nd operation schedule under a production scheduling is carried out in order to operate the work machine 10 because of there being allowance. The process retrieving and deciding the 1st operation schedule necessary for the work by both work machine 10 and 20 is executed in case of the decision result being NO. Then, the arrangement of the work machines 10, 20 is performed based on the decided next time 1st operation schedule.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a production system, and particularly to a scheduling device and a scheduling method that realize high-mix, low-volume production with high efficiency.

[Conventional technology]

As is well known, flexible manufacturing system (FMS)
Based on long-term processing plans for various workpieces set in advance and process design details for each workpiece, operation schedules for automated production equipment such as various processing (machine) machines, setup devices, automated warehouses, and conveyance equipment. It is an automatic production system that has the flexibility to create a production schedule and perform comprehensive operation control of these facilities according to the created operation schedule.

In the conventional FMS, operation control is executed approximately as follows.

That is, first of all, 1) the operation schedule that allows various automatic production equipment to operate efficiently based on the given production schedule (long-term processing schedule plan and process design information) is determined based on the type of processed product (high-mix low-volume production). ) are created sequentially according to the This is created by the host computer based on a predetermined schedule method.

2) Creation of individual driving schedules is started after driving based on the previously created driving schedule is completed. After creation, the number of materials according to the newly created operation schedule is taken out of the warehouse and placed on a pallet (processing board) to wait, and the NC data of the current operation schedule is uploaded online via magnetic disk etc. Make arrangements to download data from the computer to the FMS control device. Here, the FMS control device is composed of a computer that centrally controls the operation of the various facilities mentioned above, as well as its peripheral devices, and is configured to handle the "materials" specified each time.
A device that processes materials according to specified procedures to create a "finished product."

3) In the FMS control device, the receiver executes operation control specified for each type of automatic production equipment according to the received operation schedule. In other words, the "materials" specified according to the same operation schedule are processed according to the specified procedures to produce "finished products."
Finish it.

Here, a conventional processing line configuration is schematically shown in FIG. As shown in the figure, a pallet loaded with materials is taken out from the exit 2- of the warehouse 1-, transported, and placed on a pallet mounting table. After that, the processing machine 1 at the front stage of the processing line 30
Machining is performed at 0゛, and processing is then performed by the processing machine 20' at the subsequent stage to complete the workpiece, which is then lined out on the conveyor 31'.

[Invention or problem to be solved]

However, in a production system with a line configuration in which such processing machines are connected in series, if the takt time of the subsequent processing machine 20'' is longer than the required processing time (hereinafter referred to as takt time) of the preceding processing machine 10', In this case, even after all machining is completed by the former processing machine 10', the unprocessed part of the workpiece will continue to be processed by the latter processing machine 20-.For this reason, the former processing machine 10' Processing machine 2
Until the end of machining 0', the machined workpiece cannot be supplied to the subsequent processing machine 20' due to other machining operations, and the machining is forced to be interrupted.
This would result in a decrease in the operating rate of 0-, and in turn, a decrease in the production efficiency of the production system.

This invention was made in view of these circumstances,
In a production system with a line configuration in which operation schedules are created and determined in sequence and operation control is performed according to each operation schedule, and processing machines with different takt times are connected in series, the current operation schedule is changed to the next operation. The purpose is to provide a production system that can significantly improve production efficiency without interrupting processing in processing machines even when the schedule changes.

[Means to solve the problem]

Therefore, the present invention has a first processing machine at the front stage of the processing line and a second processing machine at the rear stage of the processing line, which requires a longer processing time than the first processing machine, and is capable of processing a given production schedule. Before the operation of the first and second processing machines, the first and second processing machines are operated based on the created operation schedule. The production system in which the operation of the second processing machine is controlled is as follows.

1° The operation schedule includes a first operation schedule in which the workpiece is completed by processing by the first and second processing machines, and a second operation schedule in which the workpiece is completed by processing only by the first processing machine. It is broadly divided into schedule,
When processing based on the first operation schedule is being performed, a workpiece that has been processed by the first processing machine but has not been processed by the second processing machine is transferred to the front stage of the second processing machine. Store in buffer.

2. The number of workpieces machined by the first processing machine is sequentially counted, and the counted number of actual workpieces, the planned number of workpieces according to the first operation schedule, and the workpiece 1 by the first processing machine are counted. A first scheduled end time until machining based on the first operation schedule is completed in the first processing machine is sequentially calculated based on the machining time per piece.

3. The number of workpieces stored in the buffer is sequentially counted, and based on the counted unprocessed number and the machining time per workpiece by the second processing machine, the first
The second operation until the machining is completed based on the operation schedule of
Sequentially calculates the scheduled end time.

4. Setting in advance the time required for setting up the operation of the first processing machine, including the process of creating the operation schedule, and determining that the calculated first scheduled end time has become smaller than this set time. Judgment is made sequentially.

5° If the first scheduled end time is found to be shorter than the set time as a result of the determination, it is sequentially determined whether or not the calculated second scheduled end time is smaller than the set time. do.

6. As a result of the determination, if the second scheduled end time is equal to or greater than the set time, instruct the start of setup for the operation of the first processing machine including a process of creating the second operation schedule; and , preparation for operation of the first and second processing machines, including a process of creating the first operation schedule if the second scheduled end time is smaller than the set time as a result of the determination; Instruct to start.

[Effect]

That is, according to this configuration, while the first and second processing machines are being operated based on the first operation schedule, the time until all processing is completed in the first processing machine is longer than the set time. If the time required to finish machining all the workpieces on the second processing machine is longer than the set time, there is a margin for the difference in takt time, so the workpieces can be processed only on the first processing machine. Arrangements are made for the second operation schedule to be completed. Then, when the setup for the second operation schedule is completed, the operation of the first processing machine based on the first operation schedule ends. After this point, the second processing machine continues to be operated based on the first operation schedule for the number of unprocessed bone works stored in the buffer. On the other hand, the first processing machine continues to be operated based on the second operation schedule.

Eventually, when the time required for all machining to be completed in the 11!2 machining machine becomes shorter than the set time, setup for the first operation schedule is started.

Then, when the second operation schedule is completed, the first and second operation schedules are
The processing machine is operated based on the first operation schedule.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of a flexible production system.

In FIG. 1, reference numeral 1 denotes a warehouse, and 10.20 denotes processing machines for performing different types of processing, which are disposed at the front stage and the rear stage of the processing line 30, respectively. 31 is a conveyor, which feeds the workpiece in the direction of arrow C. In the embodiment, it is assumed that the processing machine 20 has a longer takt time than the processing machine 10.

Note that in an actual production system, automatic production equipment includes a setup device, a robot, etc. in addition to these, but illustrations of these are omitted in the embodiment to simplify the explanation. Each automatic production equipment has a central processing unit that is a host computer, and a relay that relays control commands output from this central processing unit to each of the above production equipment and status information sent from each production equipment to the central processing unit. The operation is controlled by an FMS control device consisting of a device.

The central processing unit has an input section for inputting production schedule plans for the processing line 30, that is, long-term processing plans for various workpieces and process design details for each workpiece as human information. Based on the information input to the processing line 30, an operation schedule for controlling the operation of each production facility centered on the processing line 30 is sequentially created according to the type and number of processed products to be produced at one time on the processing line 30. Perform processing. Note that the production schedule can be changed as appropriate according to the input information from the input section. Here, the processed products produced on the processing line 30 include those that are completed by a process that combines the process of the processing machine 10 and the process of the processing machine 20, and those that are completed by the process of the processing machine 10 alone. The driving schedule that should be
There are driving schedules corresponding to the former process (hereinafter referred to as a first driving schedule) and driving schedules corresponding to the latter process (hereinafter referred to as a second driving schedule). When the driving schedule is created in the central processing unit,
The preparations for operating the automatic production equipment including the processing line 30 according to the created operation schedule, that is, the loading of materials and the contents of the created operation schedule are downloaded to the relay device as NC data and the automatic production equipment is operated. Preparations for operational control are executed.

The above-mentioned materials are carried in as follows. That is,
According to the created operation schedule, the materials necessary for processing are mounted on pallets in the necessary portions, and the jigs are assembled, and the materials are unloaded from the warehouse 1 as shown by arrow A from the exit 2 of the warehouse 1, and transferred to the transport equipment 4, etc. are transported to the pallet mounting table 6 or 7 of the processing line 30, respectively. This series of processing needs to be performed as pre-processing before processing by the processing machine 10.

The manner in which the workpiece processed by the processing machine 10 is carried out differs depending on the first and second operation schedules. That is,
In the case of the second operation schedule, the workpiece processed by the processing machine 10 is placed on a pallet on the pallet mounting table 8 or 9. When all the workpieces have been processed, the pallets are stored at the storage entrance 3 of the warehouse 1 as shown by arrow B by the transport device 5 or the like. In this way, there are two pallet mounting tables 6 and 7 in the front stage of the processing machine 10.
There are also two pallet mounting tables 8 and 9 in the latter stage, but these pallet mounting tables are added from the central processing unit via the relay device when transitioning from the current operation schedule to the next operation schedule, as will be described later. Switching is controlled according to control commands.

On the other hand, in the case of the first operation schedule, the workpieces processed by the processing machine 10 are sequentially loaded into the buffer (workpiece storage) 40 at the front stage of the processing machine 2o. The processing machine 20 sequentially takes out the workpieces loaded into the buffer 40 and processes them. That is, as described above, since the processing machine 20 has a longer takt time than the processing machine 1o, the buffer 40 is inevitably loaded with unprocessed workpieces that have been delayed in processing by the processing machine 20.

The processing machine 10 has a processing machine counting section that counts the number of processing results, that is, the number of processing operations performed on the material, and the count result of this counting section indicates that processing of one workpiece has been completed. It is applied to the central processing unit together with the end signal via the relay device. Also, buffer 4
0 also has a buffer counting section that counts the number of stored works, and the count result of this counting section is also added to the central processing unit via the relay device.

The processing performed by the central processing unit will be described below with reference to FIGS. 2 and 3. It is assumed that the vehicle is currently being driven according to the first driving schedule.

First, when a machining end signal is applied from the machining machine counter of the machining machine 10 (step 1o1), it is determined whether the following formula, t+ (y-k) < ta...(1) holds. be done. That is, in equation (1), y
is the planned number of machining in the first operation schedule that is currently being operated based on it, k is the actual number of machining achieved by the processing machine 10 in the same operation schedule (count result of the processing machine counter), and tl is the same The time t required for the processing machine 10 to process one workpiece in the operation schedule is set in advance according to the function of the processing machine 10 as the time required for creating and determining the operation schedule and setting up the operation of the processing machine 10. It's time. Then, since the left side of equation (1) is the time required to complete machining for the unprocessed bone workpiece among the currently processed workpieces, it is determined whether this time is smaller than the set time t4 on the right side. By doing so, it is determined whether or not it is time to start a series of processes such as creating, determining, and setting up the next operation schedule for the processing machine 10 (step 102). If the judgment result here is NO, the system waits for the next count result input (step 103).
). Thereafter, as long as the determination result at step 102 is NO, the processes from step 101 to step 103 are repeatedly executed.

Eventually, when the judgment result in step 102 becomes YES,
It is determined whether the following formula, t,<t2am .=(2) holds true. That is, (2)
In the equation, t2 is the time required for the processing machine 20 to process one workpiece in the first operation schedule that is currently being operated based on it, and m is the time required for the processing machine 20 to process one workpiece currently stored in the buffer 40. Number of workpieces processed (
This is the count result of the buffer counter. Here, the right side of equation (2) is the time required for the processing machine 20 to finish processing all the unprocessed bone workpieces (step 10).
4). If processing machine 20 takes longer than the set time t to finish processing all the workpieces (judgment result: YES), processing machine 1 has a margin for that difference.
A process is executed to create a second operation schedule based on the production schedule plan in order to operate 0 (step 105).
.

That is, as shown in the subroutine of FIG. 3, first, the operation schedule is sequentially searched from the production schedule, and it is sequentially determined whether or not it is the second operation schedule in which the processed product is completed using only the processing machine 10. (Step 201). When the second operation schedule is retrieved, the following calculations are performed: ta-1t, .yl...(3), and the time required to complete machining is 1. is required. Here, the subscript n indicates the reference number of the retrieved second driving schedule (step 202). Next, the following formula, 1, <1. It is determined whether or not (4) holds true, that is, whether the processing time t of the currently searched operation schedule is smaller than the processing time ir+-1 of the previously searched operation schedule. (step 203). Here, the processing time t of the driving schedule with number n-1 searched last time is the processing time t, and -1 is the processing time t of the driving schedule with number n searched this time. In the following cases (determination result No), the process moves to step 204 and shn.

The content of is set to n-1 (step 204). Further, if the processing time t1 of the operation schedule with the number n searched this time is smaller than the processing time t, -1 of the operation schedule with the number n-1 searched last time (judgment result YES),
Proceed to step 205 and set the contents of 5hno to n (
Step 205).

In this way, the processes from step 201 to step 205 are repeatedly executed, and when all the second operation schedules have been searched from the production schedule plan, finally 5h
The driving schedule with the number stored in o is selected.

The processing machine 10 is then set up based on the selected second operation schedule. That is, here,
Assuming that a material pallet is currently being placed on the pallet mounting table 7 indicated by diagonal lines in FIG. material pallets are transported and placed. Next, a process of downloading NC data necessary for the next second operation schedule is executed. Next, by looking at the count results of the processing machine counter again and successively comparing the planned number of machining y for the first operation schedule currently being implemented with the actual number of machining for the same operation schedule, It is determined whether or not the driving schedule has ended. When the number of machining results k has counted yl, that is, when the last machining process has started, the pallet mounting table 6.7 is switched and the jigs on the pallet mounting table 7 are disassembled, etc. do. If it is determined by the above determination that the first operation schedule currently in progress has ended, the pallet mounting table 8.9 is switched. At the same time, from now on, the workpieces processed by the processing machine 10 are not stored in the buffer 40. Then, the value of the planned number of machining y and the machining time t1 are reset to those of the next second operation schedule, and the next count result is waited for manually. Then, when the first operation schedule currently in progress ends, the next operation according to the second operation schedule is immediately started based on the downloaded NC data.

Now, while the above processing is being performed, step 10
The determination process No. 4 is repeatedly executed.

Eventually, when the time until the end of machining in the processing machine 20 becomes less than the set time t6 (determination result: NO), the procedure moves to step 106, searches for a first operation schedule that requires processing by both the processing machines 10 and 20, The determining process is executed. Then, the processing machines 10 and 20 are similarly set up based on the determined first operation schedule for the next time.

That is, switching of the pallet mounting table and downloading of NC data are performed as appropriate. However, when the pallet mounting table is switched, the workpieces processed by the processing machine 10 are stored in the warehouse 1 by the conveyance device 5 or the like. Along with this, after the switching, the processed workpiece is stored in the buffer 40. As a result, when the second operation schedule currently in progress ends, the next operation according to the first operation schedule is immediately started based on the downloaded NC data.

In addition, in the embodiment, when selecting the second operation schedule as shown in FIG. 3, the one with the minimum time is selected, but the method of selection is not limited to this and may be made arbitrarily. be. However, it is preferable that the operation of the processing machine 10 according to the second operation schedule ends at the same time as the previous operation of the processing machine 20 according to the first operation schedule ends. An implementation in which the second driving schedule can be selected in this manner is desirable.

〔Effect of the invention〕

As explained above, according to the present invention, in a production system with a line configuration in which processing machines with different tact times are connected in series, even when transitioning from the current operation schedule to the next operation schedule, processing with a short takt time can be performed. Since this processing machine is operated to finish processing by itself so that there is no interruption of processing by the machine, the operating rate of the processing machine is improved and production efficiency can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conceptual configuration of a production system which is an embodiment of a production system scheduling device and a scheduling method according to the present invention, and FIGS. 2 and 3 are embodiments of a production system scheduling method according to the present invention. FIG. 4 is a flowchart illustrating a schematic configuration of a conventional production system. 1... Warehouse, 2... Warehouse exit, 3... Warehouse entry, 10
．． 20...Processing machine, 40...Buffer. Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) It has a first processing machine at the front stage of the processing line and a second processing machine at the rear stage of the processing line, which requires a longer processing time than the first processing machine, and is based on a given production schedule. Before the operation of the first and second processing machines, preparations including a process of creating an operation schedule according to the type of processed product are performed, and then the first and second processing machines are operated based on the created operation schedule. In a production system that controls the operation of processing machines, the operation schedule includes a first operation schedule in which a processed product is completed by processing by both the first and second processing machines, and only the first processing machine. It is roughly divided into a second operation schedule in which a processed product is completed by the processing of A buffer for storing workpieces that have not been processed by the processing machine is provided at the front stage of the second processing machine, and the number of workpieces processed by the first processing machine is sequentially counted. Machining based on the first operation schedule is performed based on the number of actual machining results, the planned number of machining according to the first operation schedule, and the machining time per workpiece by the first processing machine.
a first calculation means that sequentially calculates a first expected finishing time until finishing in the processing machine; and a first calculation means that sequentially counts the number of workpieces stored in the buffer, and calculates the counted raw number and the second a second calculation means that sequentially calculates a second scheduled end time until the processing is completed based on the first operation schedule based on the processing time per workpiece by the processing machine; and creating the operation schedule. The time required for setting up the operation of the first processing machine including the process of a first determining means that determines, and a second calculating means that calculates a second scheduled end time when the first scheduled end time is determined to be smaller than the set time by the first determining means;
a second determining means for sequentially determining whether or not the scheduled end time has become smaller than the set time; and the second determining means determines that the second scheduled end time has become equal to or greater than the set time. and instructing the start of setup for the operation of the first processing machine including the process of creating the second operation schedule, and the second scheduled end time is smaller than the set time by the second determining means. and means for instructing the start of setup for the operation of the first and second processing machines, which includes a process of creating the first operation schedule when it is determined that the first operation schedule has been reached. (2) It has a first processing machine at the front stage of the processing line and a second processing machine at the rear stage of the processing line, which requires a longer processing time than the first processing machine, and is based on a given production schedule. Before the operation of the first and second processing machines, preparations including a process of creating an operation schedule according to the type of processed product are performed, and then the first and second processing machines are operated based on the created operation schedule. In a production system that controls the operation of processing machines, the operation schedule includes a first operation schedule in which a processed product is completed by processing by the first and second processing machines, and a first operation schedule in which a processed product is completed by processing by the first and second processing machines; It is roughly divided into a second operation schedule in which the processed product is completed by the first operation schedule, and when processing based on the first operation schedule is performed, the work is processed by the first processing machine, and the second operation schedule is processed by the second processing machine. The workpieces that have not been processed by the machine are stored in a buffer at the front stage of the second processing machine, and the number of workpieces processed by the first processing machine is sequentially counted, and this counted number of processed results and the number of processed works are stored. The processing based on the first operation schedule is performed based on the planned number of processing according to the first operation schedule and the processing time per workpiece by the first processing machine.
a step of sequentially calculating the first scheduled end time until completion in the processing machine; and a step of sequentially counting the number of workpieces stored in the buffer, and calculating the counted raw number and the second processing machine by the second processing machine. the step of sequentially calculating a second scheduled end time until the end of machining based on the first operation schedule based on the machining time per workpiece; and the step of creating the operation schedule. a step of presetting the time required for setting up the operation of the processing machine, and sequentially determining whether the calculated first expected end time has become smaller than the set time; and as a result of the determination, the first a step of sequentially determining whether or not the calculated second expected end time has become smaller than the set time when the expected end time has become smaller than the set time; 2, if the scheduled end time of step 2 is equal to or greater than the set time, an instruction is given to start setup for the operation of the first processing machine including a process of creating the second operation schedule, and as a result of the determination, the second processing machine is and a process of instructing the start of setup for the operation of the first and second processing machines, including a process of creating the first operation schedule when the scheduled end time of the processing machine becomes shorter than the set time. How to schedule a production system.