JPH01159143A - Feed instruction method for work and device thereof - Google Patents

Abstract

PURPOSE:To perform the levelling for works in reasonable manners by setting the relaxed conditions for the restriction conditions previously in a mixed flow production line and relaxing the restriction conditions in succession when works are fed and executing the feed instruction. CONSTITUTION:A vehicle work 16 which is repair-completed in a repairing yard and storing yard 18 and a vehicle work 16 which completes the foreprocess 10 are put into a waiting state in a work feeding part 20. A feed instruction control part 28 calculates if the feed position which satisfies the restriction condition for levelling is present or not, from an order memory 32 which memories the order of the vehicle works 16 on the lines 10 and 12, restriction memory 34 which memories the levelling condition necessary for obtaining a proper feeding position into a line, and a specification memory 36, from the information of the vehicle recognition parts 22 and 24, and if the feed position is detected, an instruction generation part 38 instructs to feed the work. When the feed position is not detected, the restriction conditions are relaxed stepwise, and the feed position is detected again under a new condition, and levelling is performed.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a method and apparatus for instructing the input of workpieces in a production process, particularly when a reworked workpiece is re-introduced into a mixed liquid production line, or when a previous process is The present invention relates to a workpiece input instruction method and device that can reasonably maintain workpiece leveling when the finished workpiece is inputted to a subsequent process.

[Prior Art] In the manufacturing process in a factory, for example, in the manufacturing process of vehicles, multiple types of products are often manufactured on the same line in each process.In recent years, with the diversification of consumer tastes, BACKGROUND ART High-mix, low-volume production, in which the variety of products manufactured on a line has increased in particular, has become commonplace.

Therefore, in the production process, such as the vehicle painting process or assembly process, in order to properly manage the production progress of the equipment or work and improve the overall work efficiency, the transport order of vehicle workpieces is optimized according to each process. Vehicle workpieces must be supplied to each process as a combination.

For example, in an automobile assembly factory that produces multiple car models and table models, the order of vehicles flowing on the line is standardized in order to equalize the time required for assembly work and parts consumption intervals in each process. need to be lined up. For this reason, the optimal order for each process is planned in advance during production planning, and assembly is started from the body welding process in that order.

However, despite these initial settings, there are many problems such as rework of defective cars during the painting process, returned cars, and two-tone cars.
The work is frequently removed from the line and reintroduced into the line due to circulation, etc., and the order at the start of work is disrupted, making it impossible to proceed to the final process in the same order without making any changes.

Therefore, when a vehicle that has been once removed for masking a defective vehicle or two-tone vehicle is placed in the middle of the line or reintroduced to the subsequent process, or when the initial order has changed due to a modified vehicle, the level It becomes necessary to reinsert it in a position where it does not disturb the formation.

As such a vehicle workpiece reinsertion device, a technique described in Japanese Patent Application Laid-open No. 61-31076 filed by the present applicant has been proposed, and according to this prior art, as shown in FIG. The painting line for vehicle work 16 is divided into a first process 10 and a second process 12, and a holding process 18 is provided between these processes, and the works extracted and excluded from the first process 10 are placed in this process. They are modified in the holding process 18 and controlled by the line control panel 14.

At this time, the identification information of each vehicle work 16 carried in and carried out in the first process 10 is detected by the vehicle recognition unit 22.24, and the work extracted outside the process is transferred from the holding process 18 to the second process. Identification information of the vehicle workpiece 16 when the vehicle workpiece 16 is reinserted into the workpiece 12 is detected by the reinsertion vehicle recognition unit 26. Further, the input instruction control unit 28 stores the arrangement order of the vehicle works in the first step from the identification information of each vehicle work, and determines an interrupt position that satisfies the control conditions for efficiently flowing the vehicle works.

That is, conventionally, when the identification number of a vehicle that is ready for injection is input from the input/output device 30 to the injection instruction control section 28,
As shown in FIG. 9, in step 100, a loading position that satisfies the constraint conditions is searched for in the current sequence, and the result is determined in step 110. If the loading position is found, step 120 is performed. The determined input position is specified, and if the input position is not found, an instruction indicating "no input position" is output in step 130.

In this way, the decision to re-enter the production line from the holding process 18 is automatically made, thereby increasing production efficiency.

[Problems to be Solved by the Invention] Conventional Problems However, according to the prior art described above, the constraint conditions are fixed, so if the leveling of the vehicles on the line is not too disturbed, Inserting another vehicle there would actually disturb the leveling, making it impossible to satisfy the constraint conditions, resulting in a problem in which "no insertion position" commands would be issued frequently. The probability of such a case occurring is high because the leveling of the previous process is not disturbed among the several pending processes.

Purpose of the Invention The present invention has been made to solve these problems, and includes a method for reinjecting vehicle workpieces that have been thrown out of the line into the line, and for introducing workpieces that have completed the previous process into the subsequent process. An object of the present invention is to provide a method and a device for instructing input, in which, if the constraint conditions are not satisfied, the constraint conditions are gradually relaxed within an allowable range and leveled.

[Means and operations for solving the problem] In order to achieve the above object, the method of the present invention involves flowing a plurality of workpieces to be subjected to different processing or assembly operations onto a line in a predetermined order; In a method for instructing the input of workpieces in a mixed liquid production line where the rearrangement of the workpieces is performed under predetermined constraint conditions, relaxation conditions are set in advance for the constraint conditions, and the constraint conditions are sequentially relaxed when inputting the workpieces. The feature is that the input instruction is given by

In addition, the device of the present invention includes a vehicle work recognition section that reads the identification number of the vehicle work flowing through the work line including the pre-process and post-process, and a vehicle work recognition section that is installed outside the line to remove the work that is removed from the middle of the line. When a vehicle workpiece that has been reworked in a holding process is re-introduced into the line, or when a workpiece that has completed the previous process is introduced into a subsequent process, it is determined based on the identification number of the vehicle workpiece that is waiting to be input outside the line. In a vehicle workpiece inputting instruction device comprising: a loading instruction control unit that calculates a loading position that meets constraint conditions for leveling; an instruction generation unit that calculates and instructs the workpiece input unit to calculate a loading position that satisfies the relaxed constraints while gradually relaxing predetermined constraints within an allowable range. shall be.

With the above configuration, the vehicle workpiece that has been reworked in the pending process is in a state of waiting for re-input, or the vehicle workpiece that has been completed in the previous process is in the state of waiting to be introduced, and the input instruction control unit satisfies the constraint conditions for leveling. Start calculation to determine whether there is an input position.

Here, if the loading position is found, the loading position is instructed to the workpiece loading section or the input/output device, and if the loading position is not found, it is checked whether or not predetermined constraint conditions can be relaxed.

Then, if relaxation is possible, the constraint is relaxed in a certain procedure, and an input position that satisfies the relaxed constraint is calculated. At this time, if a new loading position is found, the new loading position is instructed to the workpiece loading section in the same manner as described above, and if the loading position is still not found, a signal indicating "no loading position" is sent to the workpiece loading section.

As described above, the present invention aims at leveling by gradually relaxing the constraint conditions and re-searching for the insertion position under new conditions when the -degree insertion position is not found. It is.

[Example] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a schematic configuration of a first preferred embodiment of a vehicle work input instructing device according to the present invention.

In the figure, the work line for the vehicle workpiece 16 is divided into a front-process line 10 and a rear-process line 12, and each of these lines is controlled by a line control panel (not shown). The vehicle recognition unit 22.24 recognizes the identification number of the vehicle workpiece 16 flowing on the line 10.12, and sends the detection signal to the input instruction control unit 28.

In addition, a rework or holding area 18 as a holding process with an appropriate size is provided at an intermediate point between the pre-process line 10 and the post-process line 12, and if rework is necessary, the pre-process line 10 Vehicle workpieces 16 removed from the process are brought to the repair shop 18 and repaired as appropriate. Then, the vehicle workpiece 16 that has been modified here is reinjected into the pre-process line 10 by the workpiece inputting section 20 based on predetermined constraint conditions. Vehicles sent out from the pre-process line 10 without any modification are also temporarily placed in the holding area 18, and are also introduced into the post-process line 12 based on predetermined constraints.

At this time, the workpiece input unit 20 is also used to input the vehicle workpiece 16 that has finished the pre-process line 10 into the post-process line 12.

At this time, the input instruction control section 28 calculates a loading position that meets the constraint conditions for leveling based on the identification number of the reworked vehicle work 16, and instructs the work input section 20 with the calculation result.

The input instruction control unit 28 includes a sequence storage memory 32 that stores the arrangement order of vehicle workpieces flowing on each line, a constraint storage memory 34 that stores constraint conditions for leveling, and a specification of the vehicle workpieces. It includes a specification storage memory 36 for storing specifications.

That is, in this embodiment, the order storage memory 32
receives information from the vehicle recognition unit 22.24, and stores the arrangement of vehicle works 16 flowing on the line 10.12 as vehicle arrangement data. Further, the constraint condition storage memory 3
4 stores the conditions for leveling necessary to find the optimal insertion position in the middle of the line, and the specification storage memory 36 stores specification data for each vehicle.

Here, the characteristic feature of this embodiment is that when the input position of the vehicle workpiece cannot be found, the input instruction control unit 28 gradually relaxes the predetermined constraint conditions within an allowable range, and It includes an instruction generating section 38 that calculates a loading position that satisfies the constraint conditions and instructs the workpiece loading section.

That is, the instruction generation unit 38 receives from the input/output device 30 the identification data of vehicles that have undergone off-line work such as repairs at the rework shop 18, and selects the optimal vehicle alignment that meets the constraint conditions on the line at that time. The reloading position is calculated and the calculated reloading position is instructed to the workpiece inputting section 20 or displayed on the input/output device 30 to be instructed to the on-site worker.

First, in this embodiment, a case will be described in which a workpiece removed from the line from the middle of the pre-process line is reworked in a holding process provided outside the line, and then reintroduced to the pre-process line.

Table 1 shows an example of constraint conditions and the like according to this embodiment.

Table-1 Rn shown in parentheses in the "Condition" column in the above table indicates that the condition allows continuous work on up to n vehicles, and Kn
indicates that the condition is such that the distance between vehicle workpieces is greater than or equal to n vehicles. Further, the column "Relaxation Possibility" represents information indicating whether or not each condition can be relaxed.

Table 2 shows an example of a conversion table when the conditions Rn and Kn are relaxed.

Table 2 In this example, for the conditions of Rn, double n and K
Regarding the condition for n, n is set to approximately 1/2. Also, K
1 is a special case and is replaced by R2.

Next, based on the control flowchart shown in FIG. 3, the procedure for reinserting the vehicle workpiece will be explained.

As an example, a left-hand drive vehicle with a sunroof is arranged on the car line as shown in FIG. 2. Here, it is assumed that the constraints in Table 1 mentioned above are used.

In step 200, a re-loading position is searched and if a re-loading position is found, the process proceeds from the next step 210 to step 260, where the input position is instructed to the work input section 20 and input/output device 30. On the other hand, if there is no input position, step 220
Proceed to.

In the case of the arrangement shown in FIG. 2, there is no row in which there are four or more vehicles between sunroof vehicles at any position, so there is no position where a new sunroof vehicle can be introduced. Therefore, in this case, the constraint condition is relaxed in step 220. However, since the condition of [2 or more sunroof vehicles must be opened] in Table 1 mentioned above can be relaxed, this constraint condition is changed based on Table 2. The condition has been changed to ``There must be one or more units.'' Then, in step 230, a new insertion position that satisfies the relaxed constraint is searched for, and when the search is completed, the relaxed constraint is restored to its original state (step 235). Then, the position indicated by arrow A in FIG. 2 is found as a loading position that satisfies the conditions, and the process proceeds from step 240 to step 260, where the loading position is designated. If no input position is found, "No input position" is specified in step 250.

In the above embodiment, the constraint conditions that can be relaxed are relaxed in step 220 based on the rules in Table 2, but in other embodiments, the arrangement of vehicles on the line already satisfies the constraint conditions that can be relaxed. There are ways to mitigate this only if the In addition, as a relaxation condition other than Table 2, Rn is n
It is also possible to increase the number of units and increase the number of Kn by one unit. Further, if the control condition imposes restrictions on the appearance ratio in other formats, for example, in a sequence, the appearance ratio is changed accordingly.

As mentioned above, by relaxing the conditions that can be relaxed among the leveling constraints as necessary, the constraints can be relatively leveled at all rework stations within the line. Input instructions can be given.

In other words, in a rework site where there is less disturbance in the previous process, the conditions are relaxed and there is a high possibility that the product will be re-injected (the conventional probability of "no insertion position") is reduced.

In other words, the initial arrangement is maintained in the previous process, and as a result, there is little disturbance in the arrangement, but on the other hand, there are fewer positions where re-entering vehicles, etc. can be re-entered, and conventionally there is no input position. However, according to the present invention, by relaxing the conditions in such a case, even if leveling is slightly hindered, vehicles that need to be reworked can be brought to the vehicle line as quickly as possible without causing a stagnation. It is possible to return it. On the other hand, in the post-process repair shop, the line arrangement is inherently disordered, and as a result, even when using predetermined strict constraint conditions, it is difficult to find a line that satisfies the constraint conditions amidst such disorder. It is relatively easy to do this, and as a result, the disordered arrangement can be corrected when the reworked vehicle is reintroduced. Therefore, if the present invention is used, the probability of being able to input is increased by easing the conditions in the pre-process side of each process, and on the other hand, in the post-process where the line arrangement itself is disordered, the disorder is improved by re-inputting the reworked vehicle. This has the advantage of being able to issue input instructions that maintain a leveled alignment throughout the entire line.

Next, in this embodiment, a case will be described in which the vehicle workpiece 16 that has completed the pre-processing is introduced into the post-processing line 12 so as to meet the leveling constraint conditions.

That is, when the instruction generation unit 38 rearranges the rows of vehicle workpieces that have been disrupted in the previous process at the rework or holding area 18 under predetermined constraint conditions and inputs them into the subsequent process, the instruction generation unit 38 maintains the leveling conditions and sends them to the subsequent process. If it is not possible to input, check whether the leveling conditions in the subsequent process can be relaxed, and if it is possible to relax, check whether the vehicle workpiece can be input under the relaxed conditions, and set the loading position under the relaxed constraints. It calculates and instructs the work input unit to perform leveling that matches the production ratio of the vehicle.

FIG. 4 shows a configuration of a second embodiment of the present invention which is similar to that shown in FIG. This figure shows a loading device that can be rebuilt. Table 3 shows the 11 conditions and their relaxation conditions in this example.

The structure of the second embodiment is almost the same as that of the first embodiment shown in FIG. 1, so the same or corresponding members are denoted by the same reference numerals and the explanation thereof will be omitted.

While the first embodiment described above mainly targets the re-introduction of reworked vehicles, the second embodiment shown in FIG.
At the time of delivery from the painting process 1o in the embodiment to the assembly process 12 in the embodiment, the painted vehicle 16 is temporarily held in the holding process 18, and the control device 28 performs a predetermined process when entering the assembly process 12. It has a configuration in which it is determined whether or not the constraint condition is satisfied, and a vehicle that meets the desired constraint condition is supplied from a plurality of reserved vehicles 16 to an assembly process 12 which is a subsequent process. At the time of inputting the process, the constraint conditions, which are a feature of the present invention, are relaxed.

Condition No. 2 in Table 3 is that ``sunroof vehicles are normally used with at least two vehicles apart'', but if this condition has been checked more than once as seen from the entrance of the assembly process. For example, it shows that it is possible to relax the restrictive conditions and allow ``sunroof vehicles to have at least one space between them.''

For example, a case where the number of vehicle workpieces 16 on the line is as shown in FIG. 5 will be explained based on the control flowchart in FIG. 6.

In FIG. 5, when a sunroof vehicle 16-1 arrives from the previous painting process 10, a check is first made in step 310 to see if all the leveling conditions in Table 3 described above are satisfied.

Then, in step 320, it is determined whether or not it is possible to input the liquid while satisfying the conditions. In this example, if the sunroof vehicle 16-1 in the hold process 18 is introduced into the post-process 12, the interval between the sunroof vehicles will be one or less regardless of the position, so the sunroof vehicle cannot be introduced as is. At this time, if there is a vehicle work 16-2 other than the sunroof car 16-1 in the holding process 18, an instruction can be given to input the sunroof car 16-1 after that vehicle is input, but in this case, I can't do that either.

Therefore, a check is made to see if there are conditions that can be relaxed.According to Table 3, conditions No. 2 can be relaxed, so in step 330, the assembly process 12, which is a subsequent process,
Check whether the vehicle line-up satisfies the relaxation conditions. In the vehicle arrangement in FIG. 5, the sunroof vehicle 16
In the case of -1, the input of two or more units with an interval between them has been attempted twice, so the condition can be relaxed in step 340.

Subsequently, in step 350, the constraint conditions are changed to the relaxed conditions, and in step 360, it is checked again whether or not the vehicle workpiece 16-1 can be introduced into the assembly process 12 while all the constraint conditions are satisfied. Once this is completed, the relaxed constraints are restored (step 370).

As a result of these checks, it is determined that the vehicle workpiece 16-1 can be input (step 380), and this fact is output to the input/output device 30 to instruct the field worker.

Note that the constraint condition No. 3 in Table 3 described above prevents the non-sunroof vehicle 16-2 from being continuously introduced. That is, if we assume that only the constraint No. 2 in Table 3 exists, as shown in Figure 7, for example, the sunroof car 16-1 is pushed out due to rework, and the non-sunroof car 16-2 follows. If they are lined up, the non-sunroof vehicles 16-2 (1), 16-2 (2),
16-3 (3) will be put into the assembly process 12. Thereafter, the sunroof vehicle 16-1 that had been thrown out is reintroduced to the line, and the ratio of the sunroof vehicle 16-1 increases, and leveling is no longer achieved.

For this reason, the answer is No because three or more vehicles other than sunroof vehicles should not be input into the assembly process 12 in a row.

3 conditions are set.

By doing this, non-sunroof vehicle 16-2 (1),
16-2 (2) and 16-3 (3) are kept as they are, and then when the ratio of the sunroof vehicle 16-1 increases, this non-sunroof vehicle is used to enter the assembly process 12, and the vehicle is assembled. The ratio can be adjusted.

In other words, even if a vehicle with specifications for leveling on the line is removed due to defects, or if the proportion of vehicles for which painting work, etc. has been completed changes from time to time, the method of this embodiment can correct the fluctuation. It is possible to reduce the number of vehicles parked.

In the above-described embodiments, the workpiece supplied to the mixed liquid production line was described as a vehicle, but the present invention is applicable to any other workpieces supplied to any other processing or assembly line.

[Effects of the Invention] As explained above, the present invention includes a charging instruction control unit that gradually relaxes the loading conditions for vehicle workpieces and calculates the loading position, so that the vehicle once removed from the production line due to a defect can be If the input constraint conditions cannot be satisfied when inputting the product to the line again or inputting it to a subsequent process, the constraint conditions can be relaxed as much as possible to facilitate input to the line.

In particular, according to the present invention, the condition relaxation is performed in the front process where the line is relatively uniform, and in the post process, vehicles are introduced into the disordered line with unrelaxed constraint conditions. Therefore, there is an advantage that leveling can be made uniform throughout the entire line.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the configuration of a preferred first embodiment of the vehicle work input instruction device according to the present invention; FIG. 2 is an explanatory diagram showing the arrangement of vehicle works on a line in this embodiment; FIG. 4 is an explanatory diagram showing the configuration of a vehicle work input instruction device in a second embodiment of the present invention, and FIGS. 5 and 7 are a control flowchart in the first embodiment. Fig. 6 is a control flowchart of the second embodiment, Fig. 8 is an explanatory drawing showing a conventional example of an automatic vehicle work re-insertion device, and Fig. 9 is an explanatory drawing showing the arrangement of vehicle works in No. It is a control flowchart figure of a figure. 10... Pre-process line 12... Post-process line 16... Vehicle work 18... Repair area and holding area 20... Work input section 22.24... Vehicle work recognition section 28... Input instruction control unit 32...order storage memory 34...constraint storage memory 36...specification storage memory 38...instruction generation unit

Claims (4)

[Claims] (1) Inputting workpieces into a mixed production line where multiple workpieces that undergo different processing or assembly operations are passed through a line in a predetermined order, and the workpieces are rearranged on this line under predetermined constraints. A method for instructing workpiece input, characterized in that relaxing conditions are set in advance for the constraint conditions, and the constraint conditions are sequentially relaxed when inputting the workpieces to issue a loading instruction. (2) A workpiece input instruction method according to claim (1), wherein the relaxation of the constraint condition is performed after a predetermined number of inputs under the initial constraint condition. (3) Different machining or assembly is set for each workpiece, and each workpiece has its initial arrangement set, but detects the mixed liquid production line where rearrangement and input are performed midway through, and the arrangement of each workpiece on the line. A loading system that stores the workpiece recognition unit, line arrangement data on the line, constraint data at the time of loading, and machining or assembly data of the workpiece to be loaded, and issues loading instructions under predetermined constraint conditions based on these data. In the workpiece input instruction device including an instruction control unit, the input instruction control unit stores predetermined relaxation conditions for the constraint data, and the workpiece input position cannot be found under the initial constraint conditions. A workpiece input instruction device that is characterized in that it sometimes gradually relaxes constraint conditions. (4) In the device according to claim (3), the loading instruction control unit includes a counter device that stores the number of loading checks based on predetermined constraint conditions, and even if the loading check is performed a predetermined number of times, A workpiece loading instruction device is characterized in that it relaxes constraint conditions when a loading position cannot be found.