JP2671839B2 - Simulation equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simulation system for a production system or the like, and more particularly to a simulation system for performing a simulation on a production system or the like in a direction opposite to a time direction.

[0002]

2. Description of the Related Art In a production system, when carrying out a lot work, the work is carried out by utilizing resources such as equipment, jigs and workers. Each of these work resources has its own work capacity and is operated based on an individual operation plan. FIG.
In the production system, the lot to be worked (lot A-1) is sent to the first process of the process procedure that is daily input to the production line (lot A-2). ), Is sent to the front buffer of the station of the arrival process (Lot A-3). From the arrival of the post-process station to the start of the work, the work is awaited in the front buffer of the post-process station (Lot A-4).

If work resources are available here, the lot immediately begins process work (lot A-
5), end. Finished lot (lot A-
6) stays in the post-buffer of the station from the end of the work until it is sent to the post-process station (lot A-7). After that, the lot is sent to the station for the subsequent process (lot A-8). If there is no available work resource, the lot waits for work as a work in process in front of the work resource (lot A-9), and the lot that has completed the work of all processes is received (lots A-11, A-). 12). As a result, a waiting state occurs due to the work capacity constraint and the input plan before each work resource. Here, each station corresponding to each process (station A in FIG. 15,
When the work resources of (B, E) become available, dispatching (rapid delivery) of the waiting lot of the station is performed. At this time, the work order of the lots is determined in the waiting lot set of the station based on the dispatching rule.

In general, a simulation of a production system is performed by giving a condition of the production system and a production plan as conditions, and repeatedly executing the above-mentioned series of production activities in the normal time advancing direction to perform simulation. Then, the simulation result is used for a prediction purpose or for evaluating whether the plan satisfies the purpose. On the other hand, there is a conventional device that performs a simulation in the opposite direction to the time direction. In the conventional time reverse simulation device, the process procedure is rearranged in the reverse direction, and the sequence of events such as dispatching, work start, and work end is treated in the normal time advancing direction, and the progress of time accompanying work execution is performed. Is moved in the direction opposite to the normal time direction.

FIG. 16 shows an example of the operation of a conventional time reverse simulation device. First, each lot is sent back to the production line at each delivery date (lots B-1, B-2),
It is sent to the buffer after the end process station E (lot B-3). When the lot arrives at the station E (lot B-4), if there is an empty work resource, the work is immediately finished (lot B-5), and the start of the work is waited (lot B).
-6). Then, when the event at the processing start time is processed (lot B-7), the lot in which the work is started is immediately sent to the rear buffer of the station B in the previous process (lot B).
-8).

When there is no free work resource in the station (lot B-9), this apparatus holds the work start of the lot and creates a queue of lots in the buffer after the station B (lot B-10). . Then, when there is a vacancy in the work resource, this apparatus carries out dispatching in the rear buffer (lot B-11) and starts the work of the lot (lot B-12). When the work is started at station A, which is the leading process, the simulation time is managed so that the time advances in the reverse direction at the end of each work. In this way, the conventional apparatus repeats the above-described series of operations in the reverse direction of the work progress to perform the simulation of the production activity in the reverse time direction.

[0007]

In the conventional apparatus, the simulation time is advanced in the direction opposite to the normal time direction with the start and end of the work, and the simulation is performed by advancing the worked lot in the reverse direction of the process procedure. ing. When such a simulation procedure is carried out, when there is a vacant work resource when the lot arrives at the station and the work can be started, the work is actually started. For this reason,
The progress of the lot work is determined by the capability relationships of the stations in the opposite direction in the connected process procedure. At this time, since the capability relationship of the connected stations is opposite to that in the case of the normal direction of time progression, a result different from the case of observing the simulation result of the normal time direction in reverse is obtained.

FIG. 17 shows a state in which a simulation is performed in the normal time advancing direction. In the apparatus shown in FIG. 17, the buffers in each station are evenly processed. Further, FIG. 18 shows a state when the simulation is performed in the direction opposite to the time advancing direction. In the conventional apparatus shown in FIG. 18, due to the work capacity of the stations in the front-rear relationship, a lot has not flowed into each station, but has flowed in the pre-process direction.
Here, it can be seen that there is a problem in the conventional time reverse simulation. Such a time-reverse simulation is actually repeated with the normal time-direction simulation. Then, the conditions and the solution are converged so that the initial condition of one simulation becomes the result of the other simulation. That is, the realization of reversibility between the time-reverse simulation and the normal time-direction simulation becomes an issue.

Specifically, in the conventional apparatus, when the time reverse simulation is carried out, the queue of lots changes, and it is not possible to prepare an appropriate work wait or work in progress at the station. That is, there is a problem that the in-process distribution at a certain time when the simulation is performed in the reverse direction of the time is different from the in-process distribution at the same time when the process is performed in the normal time direction, with the normal time traveling direction simulation result as the initial state. Furthermore, when the distribution of work in progress changes, the way of changing the work order of work in progress by dispatching while waiting for work also changes. For this reason, in the lot queue in which the order of the work of the lots should be changed, an appropriate lot set cannot be created, and the work order of the work-in-process lot cannot be appropriately performed.

Generally, in the time reverse processing, the order of processing is the reverse of time, namely, work completion at the station, work start, dispatching execution, staying in the buffer before the station, buffer arrival, from the rear buffer of the previous process station. Ideally, the start of transportation should be repeated. However, according to the dispatching timing chart of the conventional apparatus shown in FIG. 19, the dispatching is performed at the time when the work is completed at the station, which causes a deviation in the dispatching timing. Further, the lot is located in the pre-process station from the time the work is started at the station where the lot is located to the time the work is transported to the pre-process station and the work is completed. For this reason, the dispatching rules of the front-end process station are applied even though the work is actually waiting for the front buffer of the station where the work is started, and the applied rules are deviated.

As a result, it is difficult for the conventional time reverse simulation device to trace the trajectory of the work of the normal time advancing direction processing in the reverse direction, and the time reverse simulation and the normal time direction simulation are performed. When the simulation is repeatedly performed, there is a problem that the condition and the solution cannot be converged. Therefore, it is an object of the present invention to converge the conditions and the solutions in the time-reverse simulation and the normal time-direction simulation and maintain the consistency of each simulation result.

[0012]

In order to solve such a problem, the present invention performs a simulation for each work target carried out on a production line or the like in a time reverse direction opposite to the time advancing direction. In the simulation device, a latest occurrence event management unit that selects the latest occurrence event that is the work object with the latest occurrence time and reverses the time, and a progress control unit that controls the work progress in the opposite time direction. It is provided. Further, there is provided a first management means for dispatching a lot indicating an unstarted work target staying in a station indicating a work process in a reverse time direction. Further, there is provided an order relation contradiction detecting means for detecting a contradiction of the work start priority order of the lot showing the work target which has not started yet staying in the station.

Further, the accommodation capacity and equipment of the buffer, which is provided in the station and accommodates the lot indicating the work target,
It is provided with a work resource operation management means for managing the operation of work resources such as workers and jigs in the reverse order of time. In addition, the second management means is provided for dispatching the lots of which the work has been completed in the station in the reverse order of time. Further, the first management means and the order relation contradiction detection means are provided. Further, a first management means and a work resource operation management means are provided. Further, a first management means and a second management means are provided.

Further, an order relation contradiction detection means and a work resource operation management means are provided. Further, an order relation contradiction detection means and a second management means are provided. Further, a work resource operation management means and a second management means are provided. Further, a first management means, an order relation conflict detection means, and a work resource operation management means are provided. Further, the first management means, the order relation contradiction detection means, and the second management means are provided. Also, the first management means,
Order relation contradiction detection means, work resource operation management means, and second
The management means of is provided.

[0015]

Operation: The latest occurrence event, which is the work target having the latest occurrence time, is selected, the simulation is performed in the reverse time direction, and the work progress is controlled in the reverse time direction. As a result, it is possible to perform a highly accurate time-reverse simulation of each work unit, and therefore, it is possible to match the timing of processing each occurrence event with the timing to be originally processed, and with a normal time-direction simulation. Can be consistent with the work results of. In addition, a lot indicating an unstarted work target staying in the station is dispatched in the reverse direction in time. As a result, if a rule that the priority evaluation determination in the time reverse processing is the opposite priority evaluation determination to the case of the normal time direction processing is applied, the processing priority defines the order of progress of the work. It is possible to maintain the consistency between the simulation result in the opposite direction of time and the work result of the normal simulation in the time direction. Further, the contradiction of the work start priority order of the lot indicating the unstarted work target staying in the station is detected. As a result, even in the time reverse simulation, the lot can be retained in the previous buffer for an appropriate time, and the work order of the lot can be determined so as to maintain consistency with the normal simulation result in the time progress direction. .

Further, the accommodation capacity and equipment of the buffer, which is provided in the station and accommodates the lot indicating the work target,
The operation of work resources such as workers and jigs is managed in the reverse order of time. Therefore, when the standard in-process amount is given to each station, the in-process amount is managed while monitoring the current in-process amount so that the lot to be transferred conforms to the known standard in-process amount of the destination station. , The flow of lots generated on the production system model can be set independently of the difference in the capability of the connecting processes. As a result, the desired work can be created at the desired station. Also,
The completed lots in the station are dispatched in reverse order in time. Therefore, when lots stay in the rear buffer and wait for the allocation of free work resources, these lots are transported in the reverse order of the work end time, that is, the rear buffer arrival time. The work order of the lot can be determined so as to maintain consistency with the simulation result in the time direction.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a simulation apparatus according to the present invention. In the figure, reference numeral 1 denotes an input unit for giving information necessary for carrying out the simulation to the apparatus,
Reference numeral 2 is an output unit for outputting the simulation result to the outside of the apparatus, 3 is a latest occurrence event management unit for selecting and executing the latest occurrence event to be described later, and performing simulation in the reverse direction of time, and 4 is a process for managing work in progress during the simulation. It is the management department. The work-in-progress management section 4 is composed of a progress control means 41 for advancing the lot work in a work procedure in the direction opposite to the normal time direction.

The operation of the embodiment apparatus thus configured will be described. When the information necessary for performing the simulation is given from the input unit 1, the latest event occurrence management unit 3
Select the latest event that has the latest occurrence time, and send the lot back to the production line at the delivery time, transfer the lot to the back buffer of the end process station, finish the lot work at the station, work the lot A series of work procedures corresponding to starting, dispatching, staying in the front buffer of the station, arrival at the front buffer of the station, start of conveyance from the rear buffer of the front process station, start of input from the front process, etc. The simulation is started in the reverse direction by proceeding in the reverse order of the normal work procedure. The latest event occurrence management unit 3 outputs the work execution result from the output unit 2 when processing the event. In this way, a series of events related to production line work is simulated in the direction opposite to the normal work progress direction, and simulation is performed for each work unit instead of for each process, so the timing at which each occurrence event is processed is originally processed. It is possible to match the timing to be performed, and thus it is possible to maintain consistency with the usual simulation result in the time direction.

FIG. 2 is a block diagram showing a second embodiment of the present invention. The work-in-progress management unit 4 of the first embodiment apparatus shown in FIG.
In addition to the above configuration, a pre-buffer management means 411 for managing loading / unloading of a lot having started the work into / from the front buffer of the station, dispatching, and the like is added. In the second embodiment configured as described above, when the latest occurrence event management unit 3 processes the event corresponding to the start of the lot work, the front buffer of the station is set to the state before the lot work is started. In order to return it, the work-in-progress management unit 4 executes work-in-process control. In this case, the progress control means 41 in the work-in-process management section 4
Controls the pre-buffer management means 411 to insert the lot into the pre-buffer of the station where the work is started. The lots inserted in the pre-buffer are subjected to retention control in the pre-buffer by the work-in-progress management unit 4.

That is, when a lot is inserted in the pre-process buffer, the latest event occurrence management unit 3 controls the progress control means 41 to determine whether the work in the pre-process station can be completed, and the lot in the pre-process station is determined. Attempt to generate the work end event of. Then, if it can be completed, the work-in-progress management unit 4 takes out the lot from the front buffer of the station based on the dispatching rule for performing the priority determination opposite to the dispatching rule in the normal time direction of the station by the front buffer managing means 411, Send to previous process station. If it cannot be completed, the work-in-process management unit 4 does not send the lot to the pre-process station, but retains the lot in the pre-buffer until work can be started at the pre-process station. In this way, paying attention to the nature of the dispatching rule in the front buffer of the station, we apply a rule in which the priority evaluation judgment in the time reverse processing is the opposite priority evaluation judgment in the normal time direction processing. Moreover, since this processing priority defines the order of progress of the work, it is possible to maintain consistency with the usual simulation result in the time direction.

Next, FIG. 3 is a block diagram showing a third embodiment of the present invention. Dispatch given in advance in the buffer of the station to the structure of the work-in-process management unit 4 of the apparatus of the first embodiment shown in FIG. The order relation contradiction detection means 4111 for performing the consistency inspection of the processing priority order relation of the lot determined by the coding rule is added. In the apparatus of the third embodiment configured in this manner, when the latest occurrence event management unit 3 processes the event corresponding to the start of the work of the lot,
In order to return the front buffer of the station to the state before the lot work is started, the latest event generation management unit 3 controls the work-in-process management unit 4 to perform the work-in-process control. Then, when a lot is inserted in the front buffer of the station, the progress control means 41 in the work-in-process management section 4 detects the order relation inconsistency detection means 411 for the lot set inserted in the front buffer.
According to 1, the order relation of lots determined by the dispatching rule of the station is obtained, and the lot with the highest priority is obtained.

If the lot inserted in the previous buffer is different from the highest priority lot, the progress control means 41 takes out the highest priority lot from the lot set in the previous buffer, and the pre-process station corresponding to the taken-out lot. Is determined, and whether or not the work at the preceding process station can be completed is determined. If the process can be completed, the progress control means 41 sends the removed lot to the pre-process station. If the termination is not possible, the progress control means 41 suspends the delivery of the removed lot to the pre-process station and puts it in the pre-buffer until the work can be started at the pre-process station. The contradiction correction ends. In this way, similar processing is performed until the lot inserted in the previous buffer and the highest priority lot match, and when the lot inserted in the previous buffer matches the highest priority lot, the progress control means 41 causes the order control conflict. The detection and contradiction correction are completed.

As described above, the progress control of the lot is performed by paying attention to the meaning of the previous buffer in the time reverse processing and the contradiction of dispatching.
That is, in the time reverse processing, the dispatching of the lot in the previous buffer is the factor that prompts the start of the work, and when the order relation of each lot in the lot set is seen at the stage when the work is started. The work starting lot must be the lot with the highest priority. At this time, if there is a lot having a start priority higher than that of the work start lot in the buffer, the work is not started by the work start lot. That is, if the work start lot is not the lot with the highest priority to start, the lot with the highest priority to start should not exist in the previous buffer at that time. Move to buffer. As a result, even in the time reverse simulation, the lot can be retained in the previous buffer for an appropriate time, and the work order of the lot can be determined so as to maintain consistency with the normal simulation result in the time progress direction. .

FIG. 4 is a block diagram showing a fourth embodiment of the present invention. The work-in-progress management unit 4 of the first embodiment apparatus shown in FIG.
In the configuration of, the in-process amount of the station at any time is predicted,
In addition, a work resource operation management unit 412 is added to perform work resource operation management and buffer capacity management to control the in-process amount of the station to a target amount. In the fourth embodiment configured as above, when the lot is inserted into the front buffer of the station, the latest event generation management unit 3 first controls the progress control means 41 of the work management unit 4 to control the work in progress. To implement. In this case, the progress control unit 41 controls the work resource operation management unit 412 to determine whether or not the capacity of the previous buffer is out of the known standard in-process value set for each buffer. If not, the top priority lot is taken out from the lot set in the previous buffer, the corresponding pre-process station is obtained for the taken-out lot, and it is determined whether or not the work at the pre-process station can be completed.

If it is possible to end, the progress control means 41
Sends the taken out lot to the previous process station. If it cannot be completed, the delivery of the taken-out lot to the pre-process station is suspended, and the lot is retained in the pre-buffer until work can be started at the pre-process station. In this way, when the standard in-process amount is given to each station, the in-process amount is managed while monitoring the current in-process amount so that the lot to be transferred conforms to the known standard in-process amount of the destination station. , The flow of lots generated on the production system model can be set independently of the difference in the capability of the connecting processes. As a result, the desired work can be created at the desired station.

FIG. 5 is a block diagram showing a fifth embodiment of the present invention. The work-in-progress management unit 4 of the first embodiment apparatus shown in FIG.
In addition to the above configuration, a post-buffer management means 413 for managing lot loading / unloading, dispatching, etc. in the post-buffer of the station is added. In the fifth embodiment configured as described above, the latest event occurrence management unit 3 processes the event corresponding to the start of the work of the lot, and when the work-started lot is sent to the preceding process station, the work in progress management unit 4
The progress control means 41 therein controls the rear buffer management means 413 to insert the lot into the rear buffer of the front process station. The progress control means 41 performs work start control for the lot inserted in the rear buffer. Here, when a vacant work resource is generated in the front process station, the progress control unit 41 controls the rear buffer management unit 413 to prioritize the arrival order of the lots inserted in the rear buffer of the front process station to the rear buffer. Dispatching is performed to process the work end event in the work resource.

As described above, in the case of performing the dispatching in the rear buffer in the time reverse processing, the dispatching operation focusing on the meaning of the rear buffer which is entered after the completion of the work is performed. In a normal simulation in the time direction, a lot is inserted into the post-buffer when the work is completed at the station, and the lot is transferred to the post-process station. On the other hand, when observing this flow from the point of view opposite to the time, the retention time in the rear buffer is set to "0", so it was transferred to the rear process because the lot was inserted in the rear buffer at that time. The reason that the lot was inserted in the rear buffer at that time is probably because the work at that station was completed at that time. In other words, at the time when each lot is inserted into the buffer, it can be considered that each lot has completed its work at that station. Therefore, in a simulation in the reverse direction of time, when lots stay in the rear buffer and wait for allocation of free work resources, these lots are transported in the reverse order of the work end time, that is, the rear buffer arrival time. As a result, the work order of the lot can be determined so as to maintain consistency with the usual simulation result in the time advancing direction.

Next, FIG. 6 is a block diagram showing a sixth embodiment of the present invention. The order relation contradiction detection means 4111 is added to the construction of the work-in-process management section 4 of the second embodiment apparatus shown in FIG. It is added. In the sixth embodiment configured in this way, when the latest occurrence event management unit 3 processes the event corresponding to the start of the work of the lot, the front buffer of the station is set to the state before the work of the lot is started. In order to return it, the latest event generation management unit 3 controls the work-in-process management unit 4 to execute the work-in-process control. Then, the progress control means 41 controls the front buffer management means 411 to insert the lot into the front buffer of the station where the work is started. The lots inserted in the pre-buffer are subjected to retention control in the pre-buffer by the work-in-progress management unit 4.

Here, when a lot is inserted in the front buffer of the station, the progress control means 41 controls the front buffer management means 411 and the order relation conflict detection means 4111 to detect the lot set inserted in the front buffer. ,
The order relation of lots determined by the dispatching rule of the station is obtained, and the lot with the highest priority is obtained. Here, if the lot inserted in the previous buffer is different from the highest priority lot, the progress control means 41 takes out the highest priority lot from the lot set in the previous buffer, and obtains the pre-process station of the taken-out lot. Determine whether work at the station can be completed. Then, if it can be completed, the removed lot is sent to the preceding process station. If it cannot be completed, the progress control means 41 suspends the delivery of the removed lot to the preceding process station. The removed lot is placed in the pre-buffer until work can be started at the pre-process station, and at this point, the order relation conflict detection and the conflict correction are completed. Thus,
The same processing is performed until the lot inserted in the previous buffer and the highest priority lot match, and when the lot inserted in the previous buffer matches the highest priority lot, the progress control means 4
1 completes the order relation conflict detection and the conflict correction.

FIG. 7 is a block diagram showing a seventh embodiment of the present invention. The work-in-progress management unit 4 of the second embodiment apparatus shown in FIG.
The above-mentioned work resource operation management means 412 is added to the above configuration. In the seventh embodiment configured as described above, when the latest occurrence event management unit 3 processes the event corresponding to the start of the work of the lot, the front buffer of the station is set to the state before the work of the lot is started. In order to return it, the work-in-process management unit 4 is made to carry out work-in-process control. In this case, the progress control means 41 controls the front buffer management means 411 to insert the lot into the front buffer of the station where the work is started. The lots inserted in the pre-buffer are subjected to retention control in the pre-buffer by the work-in-progress management unit 4.

That is, when the lot is inserted in the front buffer of the station, the latest event occurrence management section 3 controls the progress control means 41 to carry out the in-process control. In this case, the progress control unit 41 controls the work resource operation management unit 412 to determine whether or not the capacity of the previous buffer has deviated from the known standard in-process value set for each buffer. If not, the progress control unit 41 controls the front buffer management unit 411 to take out the lot from the front buffer of the station based on the dispatching rule of the buffer, and obtain the corresponding pre-process station for the taken out lot. Determine whether work can be completed at the process station. If it can be ended, the progress control means 41
Sends the taken out lot to the previous process station. If it cannot be completed, the delivery of the taken-out lot to the pre-process station is suspended, and the lot is retained in the pre-buffer until work can be started at the pre-process station.

FIG. 8 is a block diagram showing an eighth embodiment of the present invention. The work-in-progress management section 4 of the second embodiment apparatus shown in FIG.
The above-mentioned post-buffer management means 413 is added to the above configuration. The operation of the latest occurrence event management unit 3 of the apparatus of the eighth embodiment configured as described above is the same as that of the first embodiment, and therefore its explanation is omitted. Further, the processing operation of the work start event of the lot by the progress control means 41 of the work-in-progress management unit 4 is similar to that of the second embodiment, and therefore its explanation is omitted. Further, the preceding process lot transfer processing operation by the progress control means 41 and the work end event processing operation by the rear buffer management means 413 are the same as those in the fifth embodiment, and therefore their explanations are omitted.

FIG. 9 is a block diagram showing a ninth embodiment of the present invention. The work-in-progress management unit 4 of the third embodiment apparatus shown in FIG.
The work resource operation management means 412 is added to the above configuration. In the ninth embodiment configured in this way, when the latest occurrence event management unit 3 processes the event corresponding to the start of the work of the lot, the front buffer of the station is set to the state before the start of the work of the lot. In order to return, the work-in-process management unit 4 performs work-in-process control. Here, when the lot is inserted in the front buffer of the station, the progress control means 41
The order relation contradiction detection unit 4111 obtains the order relation of the lots defined by the dispatching rule of the station for the lot set inserted in the previous buffer, and obtains the highest priority lot.

Here, when the lot inserted in the previous buffer is different from the highest priority lot, the progress control means 41 takes out the highest priority lot from the lot set in the previous buffer and obtains the preprocess station of the taken out lot. , It is determined whether or not the work at the preceding process station can be completed. If the process can be completed, the progress control means 41 sends the removed lot to the pre-process station. If it cannot be completed, the delivery of the removed lot to the front process station is suspended. The removed lot is placed in the pre-buffer until work can be started at the pre-process station, and at this point, the order relation conflict detection and the conflict correction are completed. Thus,
The same processing is performed until the lot inserted in the previous buffer and the highest priority lot match, and when the lot inserted in the previous buffer matches the highest priority lot, the progress control means 4
1 completes the order relation conflict detection and the conflict correction.

Further, the progress control means 41 controls the work resource operation management means 412 to judge whether or not the capacity of the previous buffer is out of the known standard in-process value set for each buffer. If not, the progress control unit 41 takes out the highest priority lot from the lot set in the previous buffer, finds the corresponding pre-process station for the taken-out lot, and determines whether the work at the pre-process station can be completed. If it can be ended, the progress control means 4
1 sends the taken-out lot to the front-end process station. If it cannot be completed, the delivery of the taken-out lot to the pre-process station is suspended, and the lot is retained in the pre-buffer until work can be started at the pre-process station.

FIG. 10 is a block diagram showing a tenth embodiment of the present invention, in which a post-buffer management means 413 is added to the construction of the work-in-process management section 4 of the third embodiment apparatus shown in FIG. The operation of the latest event occurrence management unit 3 of the apparatus according to the tenth embodiment configured as described above is the same as that in the case of the first embodiment, and the description thereof will be omitted. In addition, the in-process management unit 4
Since the processing operation of the lot work start event by the progress control means 41 is similar to that in the third embodiment, the description thereof will be omitted. Further, the processing operation of the work end event by the post-buffer management means 413 is also similar to that of the fifth embodiment, and therefore its explanation is omitted.

FIG. 11 is a block diagram showing an eleventh embodiment of the present invention, in which a post-buffer management means 413 is added to the construction of the work-in-progress management section 4 of the fourth embodiment apparatus shown in FIG. The operation of the latest event generation management unit 3 of the eleventh embodiment configured as described above is the same as that of the first embodiment, and the description thereof is omitted. In addition, the in-process management unit 4
The processing operation of the lot work start event by the progress control means 41 is also the same as in the case of the fourth embodiment, and therefore its explanation is omitted. Furthermore, since the preceding process lot transfer processing operation by the progress control means 41 and the work end event processing operation by the rear buffer management means 413 are the same as those in the fifth embodiment, the description thereof will be omitted.

FIG. 12 is a block diagram showing a twelfth embodiment of the present invention, in which a work resource operation management means 412 is added to the construction of the work-in-process management section 4 of the sixth embodiment device shown in FIG. . In the twelfth embodiment configured as described above, when the latest occurrence event management unit 3 processes an event corresponding to the start of the work of the lot, the front buffer of the station is set to the state before the work of the lot is started. In order to return it, the in-process management unit 4 executes in-process control. Progress control means 41
Controls the pre-buffer management means 411 to insert the lot into the pre-buffer of the station where the work is started.
The lots inserted in the pre-buffer are subjected to retention control in the pre-buffer by the work-in-progress management unit 4. Here, when the lot is inserted in the front buffer of the station, the progress control means 41 controls the front buffer management means 411 and the order relation inconsistency detection means 4111 to dispatch the station to the lot set inserted in the front buffer. The order relation of lots determined by the ringing rule is obtained, and the lot with the highest priority is obtained.

If the lot inserted in the previous buffer is different from the highest priority lot, the progress control means 41 takes out the highest priority lot from the lot set in the previous buffer, and the pre-process station corresponding to the taken out lot. Is determined, and whether or not the work at the preceding process station can be completed is determined. Then, if it can be completed, the removed lot is sent to the preceding process station. If it cannot be completed, the delivery of the removed lot to the front process station is suspended. The removed lot is placed in the pre-buffer until the work can be started at the pre-process station, and at this point, the order relation conflict detection and the conflict correction are completed. In this way, the same processing is performed until the lot inserted in the previous buffer and the highest priority lot match, and when the lot inserted in the previous buffer matches the highest priority lot, the progress control means 41 causes the work resource to operate. The management means 412 is controlled to determine whether or not the capacity of the previous buffer is out of the known standard in-process value set for each buffer.

If not, the highest priority lot is taken out from the lot set in the previous buffer, the corresponding pre-process station is determined for the taken-out lot, and it is judged whether or not the work at the pre-process station can be completed. If it is determined that the work can be completed, the progress control means 41 sends the taken-out lot to the pre-process station. If the completion is not possible, the progress control means 41 suspends the delivery of the taken-out lot to the pre-process station, and retains the lot in the pre-buffer until work can be started at the pre-process station.

FIG. 13 is a block diagram showing a thirteenth embodiment of the present invention, in which a post-buffer management means 413 is added to the structure of the work-in-process management section 4 of the sixth embodiment apparatus shown in FIG. Note that the operation of the latest event occurrence management unit 3 in the apparatus of the thirteenth embodiment configured in this way is the same as that of the first embodiment, so its explanation is omitted. Further, the processing operation of the work start event of the lot by the progress control means 41 of the work-in-progress management unit 4 is similar to that of the sixth embodiment, and therefore its explanation is omitted. Further, the preceding process lot transfer processing operation by the progress control means 41 and the work end event processing operation by the rear buffer management means 413 are the same as those in the fifth embodiment, and therefore their explanations are omitted.

FIG. 14 is a block diagram showing a fourteenth embodiment of the present invention, in which a post-buffer management means 413 is added to the configuration of the work-in-process management section 4 of the twelfth embodiment apparatus shown in FIG. In the fourteenth embodiment configured in this way, when the latest occurrence event management unit 3 processes the event corresponding to the start of the work of the lot, the front buffer of the station is set to the state before the work of the lot is started. In order to return it, the in-process management unit 4 executes in-process control. Progress control means 41
Controls the pre-buffer management means 411 to insert the lot into the pre-buffer of the station where the work is started.
The lots inserted in the pre-buffer are subjected to retention control in the pre-buffer by the work-in-progress management unit 4. Progress control means 41 when a lot is inserted in the front buffer of the station
Controls the pre-buffer management means 411 and the order relation conflict detection means 4111 to obtain the lot order relation determined by the dispatching rule of the station for the lot set inserted in the front buffer, and has the highest priority. Ask for lots.

Here, if the lot inserted in the previous buffer is different from the highest priority lot, the progress control means 41 takes out the highest priority lot from the lot set in the previous buffer, and the front process station corresponding to the taken out lot. Then, this lot is inserted into the rear buffer of the front process station removed by the rear buffer management means 413. In this way, the same processing is performed until the lot inserted in the previous buffer and the highest priority lot match, and when the lot inserted in the previous buffer matches the highest priority lot, the progress control means 41 causes the work resource operation management. Controlling the means 412,
It is determined whether or not the capacity of the previous buffer does not deviate from the known standard in-process value set for each buffer. If not, the progress control means 41 takes out the highest priority lot from the lot set of the previous buffer, finds the corresponding pre-process station for the taken-out lot, and takes the lot taken out by the post-buffer management means 413 as the pre-process. Insert in the buffer after the station. If the standard work-in-process value is exceeded, the lot transportation to the previous process is suspended.

When the lot is inserted into the rear buffer of the front process station, the latest event management means 3 controls the progress control means 41 to try to generate a work end event of the lot. Then, a request for allocating the vacant work resource of the preceding process station is made, and when the work resource exists, the latest occurrence event management means 3 causes a work end event of the lot. When there is no work resource, the occurrence of the work end event of the lot that has arrived at the rear buffer of the front process station is suspended. When the latest occurrence event management means 3 processes an event corresponding to the start of work of a lot, the progress control means 41
A work end event for the lot is generated to end before the work starts. At this time, the progress control unit 41 controls the rear buffer management unit 413 to dispatch the lots inserted in the rear buffer in order of arrival order to the rear buffer and process the work end event in the work resource. finish.

The operation of such a fourteenth embodiment device is shown in FIG.
0 is shown. Note that, in FIG. 20, station A has busy facilities # 1 to # 3 and idle (I).
dle) equipment # 4, next station B has busy equipment # 1 to # 3, and tail station E has busy equipment # 1 and idle equipment # 2 to # 4 as production equipment. Be present. In such a situation, first, each lot is reversely fed to the production line (lots C-1 and C-2), and then transported to the rear buffer of the end process station E (lots C-3 and C). -4) is performed. Then the work at station E is completed (lot C
-5, C-6), work start (lot C-7), dispatching implementation (lot C-8), stay in the front buffer of the station (lot C-9), buffer arrival (lot C-10), A series of events such as conveyance start from the rear buffer of the front process station (lots C-11 and C-12) and start of loading from the top process (lots C-13 and C-14) are repeated in the direction opposite to the time advancing direction. . As a result, it is possible to create a work waiting list or a work in process at an appropriate station.

With this configuration, it is possible to minimize the deviation of the lot work progress process between the simulation in the time direction and the simulation in the time opposite direction.
It is possible to achieve the convergence of the conditions and the solution in the case of repeatedly performing the time backward simulation and the normal time traveling direction simulation, which is an actual application example of the time backward simulation. Therefore, efficient production planning can be made.

[0047]

As described above, according to the present invention, the latest occurrence event, which is the work object having the latest occurrence time, is selected, the simulation is performed in the reverse time direction, and the work progress is controlled in the reverse time direction. As a result, it is possible to perform highly accurate time reverse simulation for each work unit.
Therefore, the timing of processing each occurrence event can be matched with the timing to be originally processed, and the consistency with the work result in the normal simulation in the time direction can be maintained. In addition, since the lot indicating the unstarted work object staying in the station is dispatched in the time reverse direction, the priority evaluation judgment in the time reverse processing is the same as the normal time direction. If such a rule is applied, the processing priority defines the order of the progress of the work, so that it is possible to maintain the consistency between the simulation result in the opposite direction of time and the work result of the normal simulation in the time direction. In addition, since the inconsistency in the work start priority order of the lot indicating the unstarted work target staying in the station is detected, the lot can be held in the previous buffer for an appropriate time even in the time reverse simulation. Therefore, the work order of the lot can be determined so as to maintain consistency with the usual simulation result in the time advancing direction.

Further, the accommodation capacity and equipment of the buffer provided in the station for accommodating the lot indicating the work target,
Since the operation of the work resources such as workers and jigs is managed in the reverse direction of time, when the standard work in progress is given for each station, the lot to be transferred is the known standard work in progress at the transfer destination station. In order to comply with the above, since the amount of work in progress is managed while monitoring the current amount of work in progress, it is possible to set the flow of lots generated on the production system model independently of the difference in the capacity of the processes to be connected. . As a result, the desired work can be created at the desired station. In addition, since the completed lots in the station are dispatched in the reverse order of time, when lots stay in the rear buffer and wait for the allocation of empty work resources, the transfer of these lots is completed at the work end time, That is, the processing is performed in the reverse order of the arrival time of the rear buffer, and as a result, the work order of the lot can be determined so as to maintain consistency with the simulation result in the normal time advancing direction.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing a second embodiment.

FIG. 3 is a block diagram showing a third embodiment.

FIG. 4 is a block diagram showing a fourth embodiment.

FIG. 5 is a block diagram showing a fifth embodiment.

FIG. 6 is a block diagram showing a sixth embodiment.

FIG. 7 is a block diagram showing a seventh embodiment.

FIG. 8 is a block diagram showing an eighth embodiment.

FIG. 9 is a block diagram showing a ninth embodiment.

FIG. 10 is a block diagram showing a tenth embodiment.

FIG. 11 is a block diagram showing an eleventh embodiment.

FIG. 12 is a block diagram showing a twelfth embodiment.

FIG. 13 is a block diagram showing a thirteenth embodiment.

FIG. 14 is a block diagram showing a fourteenth embodiment.

FIG. 15 is a diagram showing a flow on the production system in the normal time direction.

FIG. 16 is a diagram showing a conventional time-reversed simulation example.

FIG. 17 is a diagram showing a simulation example in the normal time direction.

FIG. 18 is a diagram showing a conventional time-reversed simulation example.

FIG. 19 is a diagram showing a dispatching timing of a conventional device.

FIG. 20 is a diagram showing an operation of the fourteenth embodiment device.

[Explanation of symbols]

1 ... input part, 2 ... output part, 3 ... latest occurrence event management part, 4
... work-in-progress management unit, 41 ... progress control means, 411 ... front buffer management means, 412 ... work resource operation management means, 413 ...
Rear buffer management means 4111 ... Order relation conflict detection means.

 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-2-42503 (JP, A) JP-A-5-233590 (JP, A) INOUE I. ET. AL. , "BACKWARD SIMULATION-CONCEPT, METHODOLO GY AND TOOL", IMCS WORLD CONGRESS ON SCIENTIFIC COMPUTA TION (11TH) OSLO, PP. 325-330 (1986).

Claims (14)

(57) [Claims] 1. A latest occurrence event, which is a work object having the latest occurrence time, in a simulation device for performing a simulation in a time reverse direction opposite to a time advancing direction for each work object performed on a production line or the like. And a progress control means for controlling the work progress in the reverse time direction. 2. The simulation apparatus according to claim 1, further comprising: first management means for dispatching a lot indicating an unstarted work target staying in a station indicating a work process in a reverse time direction. And a simulation device. 3. The simulation apparatus according to claim 1, further comprising an order relation contradiction detection means for detecting a contradiction in a work start priority order of a lot that is staying in a station indicating a work process and indicates an unstarted work target. Simulation device characterized by. 4. The simulation apparatus according to claim 1, wherein a storage capacity and equipment of a buffer, which is provided in a station indicating a work process and stores a lot indicating the work target,
A simulation device comprising a work resource operation management means for managing the operation of work resources such as workers and jigs in a reverse time direction. 5. The simulation apparatus according to claim 1, further comprising second management means for dispatching, in a reverse direction of time, a lot, which is a work target whose work has been completed, in a station indicating a work process. And a simulation device. 6. The simulation apparatus according to claim 2, further comprising an order relation contradiction detection unit that detects a contradiction in a work start priority order of the lot that is the work target that waits for a work start. 7. The simulation apparatus according to claim 2, wherein the capacity of the buffer accommodating the lot to be operated and the operation of the operation of the work resources such as equipment, workers, and jigs are managed in the reverse direction in time. A simulation device comprising resource operation management means. 8. The simulation apparatus according to claim 2, further comprising second management means for dispatching the lot, which is the target of work, for which the work has been completed, in a reverse time direction. 9. The simulation apparatus according to claim 3, wherein the capacity of the buffer in which the lot to be operated is accommodated and the operation of operation of operation resources such as equipment, workers, and jigs are managed in reverse order in time. A simulation device comprising resource operation management means. 10. The simulation apparatus according to claim 3, further comprising second management means for dispatching the lot, which is the target of work, for which the work has been completed, in a reverse time direction. 11. The simulation apparatus according to claim 4, further comprising second management means for dispatching the lot, which is the target of work, for which the work has been completed, in a reverse direction of time. 12. The simulation apparatus according to claim 6, wherein the capacity of the buffer in which the lot to be operated is accommodated and the operation of operation of operation resources such as equipment, workers, and jigs are managed in reverse order in time. A simulation device comprising resource operation management means. 13. The simulation apparatus according to claim 6, further comprising second management means for dispatching the lot, which is the target of work, for which the work has been completed, in a reverse time direction. 14. The simulation device according to claim 12, further comprising second management means for dispatching the lot, which is the work target, for which the work has been completed, in a reverse time direction.