JP2510338B2 - Assembly sequence planning system and assembly sequence planning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an assembly sequence planning technique for planning the order of the injection types to an assembly line of a mixed-flow production system for assembling a product group to which various options are added. Relates to a method and system for implementing the technology.

[Conventional technology]

In the above-described production method, the daily production model number, that is, the production number of each option to be added is fixed before one regular day of assembly, for example, the day before. The work that determines the order in which the production models for one day are sent to the assembly line is called the assembly sequence plan. The most basic idea in this assembly sequence plan is leveling, and the man-hour load in each process It is important to stabilize the process by minimizing the fluctuation of

Conventionally, this plan preparation is performed by manually judging the quality of the plan and making trial and error to remedy the defective points that cause the concentration of the load. To avoid this, automation using a computer is being considered.

For example, there is an OR-like modeling method that calculates the line balance using standard man-hours in order to obtain the optimum solution of the assembly sequence plan. However, the problem of the assembly sequence planning has complicated constraints, and the conditional expression of the model can be solved only by calculating the combination of all the sequences and determining the optimum solution. This method is not practical because the number of combinations explosively increases and even if a high-speed computer is used, this calculation is impossible in a realistic time.

For this reason, instead of obtaining a solution with mathematical rigor, it is conceivable to create an assembling order based on a certain kind of rule so as to obtain a satisfactory solution. In this case, in order to perform the sorting process that was conventionally performed based on the personal know-how of the staff of the manufacturing department etc. at a speed practically sufficient for the computer, the conventional sorting know-how is mathematically It is essential to establish a new sorting method derived by analysis.

[Problems to be Solved by the Invention]

An object of the present invention is to realize a rearrangement process in which the obtained assembling order can be performed with a practically sufficient speed and refining with respect to the option of interest in the technique of planning the order of the injection type into the assembly line of the mixed production system. Is.

[Means for solving the problem]

In order to solve the above-mentioned problems, in the assembly sequence planning method according to the present invention, an option to be noted is sequentially selected from a plurality of options according to priority, and products to which the selected options are added are evenly assembled on an assembly line. Sorting step for rearranging the assembly order in order to flow to the target, Levelness evaluation step for calculating the level of equality for the assembly order sorted for the option of interest, Levelness calculated by the leveling evaluation section And a comparison step for determining whether or not the rearranged order is satisfied by comparing with a preset reference value of the corresponding option, and the rearrangement step is a peak load center for the attention option. Section and the widest Bay Cantor Road center are replaced to promote leveling. It is equipped with a step, and a bay cant road replacement step that promotes leveling by replacing the element at the rear of the bay cant road, which is an option of interest, with the element at the optimal spacing position.

In addition, the assembly sequence planning system according to the present invention sequentially selects, from a plurality of options, an option to be noticed in accordance with the priority and distributes the products to which the selected options are added to the assembly line evenly. A sorting processing unit that sorts the items, a leveling degree evaluation unit that calculates the leveling degree for the assembly order sorted for the selected option, and a leveling degree calculated by the leveling degree evaluation unit in advance. A comparison unit that determines whether the rearranged order is satisfied by comparing with the set reference value of the selected option, and a control that controls the rearrangement processing unit, the levelness evaluation unit, and the comparison unit described above. And a rearrangement processing unit replaces the peak load center with the widest bay cant load center for the selected option. The peak load replacement means that promotes leveling by performing the following, and the bay cant that promotes leveling by exchanging the backward option element of the option of interest and the element at the optimal spacing position. It is composed of a load exchange means.

[Work]

Select the most noticeable option from multiple options in order of priority and sort the assembly order to distribute the products to which this selected option is added evenly to the assembly line. The peak load swapping process that sorts the elements in the empty part with the elements in the empty part, and the rearward element in the empty part is replaced with the element at the optimal interval position. The bay cant load replacement processing to be performed is selectively activated according to a predetermined rule, and the arrangement is leveled so as to satisfy a predetermined criterion regarding the option of interest.

〔The invention's effect〕

Satisfaction that when sorting, only the peak load swapping means that swaps the element of the most concentrated part with the element of the most vacant part becomes better when one part becomes better and the other part becomes worse. Situations in which the solution oscillates with a level that cannot be achieved often occur, and it is not possible to find a satisfactory solution. Satisfactory leveling can be obtained at a practical speed. Furthermore, in the sorting process that sequentially selects and pays attention to the options that should be focused on from multiple options according to their priority, the sorting performed by peak load swapping or bay cant load swapping is based on that level of standardity. By being performed while checking, the desired leveling regarding all of the plurality of options to be noticed is realized while guaranteeing quantitative accuracy.

[Other features]

As a preferred combination control of the peak load exchanging means and the bay cant load exchanging means, in a preferred embodiment according to the present invention, as long as the bay cant load occurs, the bay cant load exchanging means is used,
It is proposed to perform the leveling by the peak load exchanging means once when the bay cant load disappears, and then execute the bay cant load exchanging means again if the bay cant load occurs. With such control, the leveling level can be improved without losing the high speed of the peak load replacement method.

〔Example〕

The overall configuration of the assembly sequence planning system according to the present invention is the first
It is shown in the figure. The input unit 1 which receives the model of the product to be assembled for one day and the presence / absence of various options and the number of them from the host computer through the communication means or the magnetic or optical storage means receives the data from the I / O interface. Send to 2. The interface 2 has the function of converting this data into a format readable by the central processing unit of the system. On the contrary, it also has a function of sending the result derived by the central processing unit to the output unit 3 such as a printer or a CRT.

The central processing mechanism is composed of a rearrangement processing unit 4, a leveling degree evaluation unit 5, a comparison unit 6, a reference value changing unit 7, and a control unit 8 which controls these in a centralized manner. Sorting processing unit 4
Basically rearranges the assembly order based on the rearrangement rule necessary to make the products having the options to be noticed evenly flow through the assembly line without making them as continuous as possible. The leveling degree evaluation unit 5 calculates the leveling degree based on a rule which will be described in detail later with respect to the assembling order rearranged with respect to the option of interest.
The peak load evaluation part that calculates the peak load evaluation value that indicates the degree of concentration of the option of interest, the variation evaluation part that calculates the variation evaluation value that indicates the degree of dispersion of the option of interest, and the optimal interval for this option Based on this, a weighting coefficient for each of the peak load evaluation value and the variation degree evaluation value is determined, and a leveling degree calculation unit for calculating the leveling degree for the option of interest is provided. The comparing unit 6 compares the leveling degree calculated by the leveling degree evaluation unit with a preset reference value of the corresponding option and determines whether or not the rearranged order is satisfactory. Further, the reference value changing unit 7, which is used in a special case, has a function of lowering the reference value of a specific option when the rearrangement cannot be achieved due to mutual interference between the options. The control unit 8 controls the rearrangement processing unit 4, the leveling degree evaluation unit 5, the comparison unit 6, and the reference value change unit 7 described above, and based on the daily production information input to this system, Derive a satisfying assembly sequence by focusing on the options with the highest priority.

Next, a schematic flow of processing of the assembly sequence planning system according to the present invention will be described with reference to the flowchart shown in FIG.

In step 10 (hereinafter referred to as # 10), the data indicating the product to be assembled for one day, which is sent via the input unit 1, is loaded into the work area of this system. In # 15, a reference value, that is, a rearrangement passing score, is set for each option given to the input product to be assembled. In # 20, it is determined whether or not there is a noticeable option for rearranging the ranking, and if YES, the process proceeds to # 25. In # 25, the rearrangement processing unit 4 rearranges the options of interest. This rearrangement is performed using a method described later, for example, under the rearrangement constraint condition that the previously defined order of the high-priority option that has been focused on is not rearranged. In # 30, the level evaluation unit 5 calculates the level for the order rearranged in # 25. In # 35, the calculated level and the standard value are compared, and if the level is higher than the standard value, it jumps to # 20 to check whether there is a remarkable option to sort next. If the levelness falls below the standard value, proceed to # 40. In # 40, the list of products with higher priority higher priority options that were noticed earlier than the currently focused option was released, that is, the constraint conditions for higher options were relaxed Sorting is performed as long as the evaluation value of the option exceeds the corresponding reference value. # 45 and # 50, # 30
Similar to # 35 and # 35, the level is calculated, and the level is compared with the reference value. If the level exceeds the standard, jump to # 20. If the level is less than the standard, go to # 60. Proceed and inquire whether to change the reference point and rearrange again. If YES, jump to # 15 and set the reference value again. If no, jump to # 20. If NO in # 20, that is, if there are no more options to be noted, the final result is output in # 65, and the process ends.

Next, the rearrangement method and the leveling degree calculation method in the rearrangement process will be described. First, a few words and phrases used for this purpose will be defined.

The number of units in an interval state when products with options are evenly distributed is called an "optimal interval". That is, the optimum interval = (total number of products-number of units with options) / number of units with options However, when the number of units of products with options is 0, the optimal interval is set to 0, and the number of units of products with options is When it exceeds 50% of the total number, even if the optimal interval is optimally distributed, the number of consecutive machines is the optimal interval. When the optimum interval is not an integer, the rounded up value is called the optimum wide interval, and the rounded down value is called the optimum narrow interval.

When paying attention to a given option in the assembly sequence of products for one day, there is an option that includes the part with the largest number of continuous units when there is a sequence, and the part with the smallest number of units when there is no sequence. Each of the parts is called "peak load". When there are multiple peak loads, the part is called "peak load set".

In the assembly sequence of products for one day, when a certain interval of a predetermined option is larger than the optimum wide interval, the part is called "bay cant road set", and the set is called "bay cant road set".

In the present invention, a peak load replacement method and a bay cant load replacement method are used as a replacement processing method. The peak load replacement method is the peak load center part and the widest bay cant load center part regarding the option of interest. It is a method that promotes leveling by exchanging, and the bay cant road swapping method is a leveling method by swapping the bayant road rear element of the option of interest and the optimal spacing position. Is a method of promoting. Here, a bay cant road rear element is when the distance between the front element and the rear element having the option of interest is larger than the above-mentioned optimum wide distance (that is, bay cant road).
In, the rear element. Further, the element of the optimum spacing position is an element which does not have the option of attention to form the optimum wide spacing in the bay cant road.

In order to improve the leveling level with sufficient speed, the bay cant load replacement method is used as long as the bay cant road occurs, and the peak load replacement method is used once when the bay cant road disappears. After leveling, it is desirable to mix both methods, such as performing baycant load replacement again if baycant load has occurred.

The levelness evaluation unit calculates the levelness regarding the option to be noted for the given assembly sequence by the following formula: Levelness = (W * G + (1-W) * H) * 100 where G Is a variation evaluation value, and when Y = <X, (X: set of actual intervals, Y: set of optimum intervals) G = Σ (Y / X) / production quantity with option Y> X, G = Σ (Y / X) / Production quantity with option H is the peak load evaluation value. When the peak load is an interval, H is the peak load interval quantity / optimum narrow interval (if the value exceeds 1, all 1 When the peak load is continuous, H = 0 W is the weight of the variation evaluation value, and when S => 1, (S: optimum interval or optimum wide interval) W = 1 / S S <1 When, W = 1.

Next, the actual rearrangement and the calculation of the levelness thereof will be described using the example shown in FIGS. 3 (a) to 3 (r).

In each drawing, the horizontal sequence indicates one product, and each number, that is, "1" or "0", indicates whether or not each option is provided. For example, the product indicated by "0100" has no first option, has a second option, and has no second and third options. As is apparent from the figure, 10 products are planned in this example, and the number of options is 5. It should be noted that when this assembly order is determined, the assembly order prior to this must be taken into consideration, but here it is assumed that there were three optional intervals last time. Also, the standard value of each option, that is, the passing score for sorting, is 60, 5 in order from the first option.
0, 40, 30, 20 points.

Rearrangement process First step ... Figs. 3 (a) to 3 (b) First, attention is paid to the first option. As described above, there are three gaps from the previous issue, and there is one gap at the beginning in this data, so there are a total of four gaps. Since the optimum interval of the first option is 3, the bay cant road rearrangement is carried out so that the over-empty portion is stacked. In other words, since the first option has no restrictions on upper options, the first stage (the product shown in the top row of the side-by-side sequence) and the second stage (the product shown in the second stage of the side-by-side sequence)
Replace. Here, the high-order option is a sort process in which a plurality of options are selected in order according to their priority and sorted, and, for example, in the sort focusing on the option "component A", It is an option with a higher priority that has already been used for sorting, that is, a higher priority than "Part A".

2nd step ... Fig. 3 (b) to Fig. 3 (c) Since the interval is 4 between the 3rd stage and the 8th stage for the first option, the bay cant road rearrangement is further performed. The 7th and 8th steps are swapped.

3rd step ... FIG. 3 (c) to FIG. 3 (d) With respect to the first option, the peak load relocation is performed because there are no more than three optimum intervals.
First, the most dense part is searched, but here the uppermost part and the third part are one interval, so the uppermost part is moved to the least dense part. Here, the uppermost stage is moved, but if this is assumed to disappear, there will be 5 intervals counted from the previous time. It is good to replace one of these, but the data of the previous day has already been issued and cannot be replaced. Therefore, 8
・ Aiming at the 3rd interval of the 9th and 10th stages, these are the targets for replacement, but it is not necessary to replace them with the 8th and 9th stages, so the 10th stage is replaced with the top stage.

4th step ... FIG. 3 (d) to FIG. 3 (e) Considering the previous data, since 5 intervals have occurred between the 3rd and the 3rd, bay cant road rearrangement is performed,
The top row and the third row are swapped, and the interval is 3.

Fifth step ... FIG. 3 (e) to FIG. 3 (f) Since there are 5 intervals between the uppermost stage and the 7th stage, bay cant road rearrangement is performed and the 5th stage and 7th stage. The steps are replaced.

6th step: Fig. 3 (f) to Fig. 3 (g) Since there are 4 intervals between the 5th and 10th stages, the bay cant road is rearranged and the 9th stage The 10th row is replaced.

The rearrangement processing from the first step to the sixth step completes the rearrangement regarding the first option. Here, the levelness of this order is calculated as follows using the above-mentioned formula.

As you can see from Figure 4, Option 1
Regarding the intervals of, considering the result of the previous day, three intervals are lined up, and the interval set is {3, 3, 3}. The last interval cannot be decided unless the order of the next day is decided, so it is excluded from the target of the levelness here. Since the number of units produced is 10 and 3 of them have the first option, the set of optimal intervals is {3, 2, 2}. However,
This set has numerical values of its elements arranged in descending order. First, the variation evaluation value is G = (3/3 + 2/3 + 2/3) /3=0.778 The peak load evaluation value has a peak load interval of 3, so H = 3/2 = 1.51, so H = 1. .

Further, the weight W of the variation evaluation value has an optimum interval of 3
Therefore, W = 1/3 = 0.333 Therefore, levelness = (0.333 * 0.778 + (1-0.333) * 1) * 100 = 93 ... Rounding up the decimal point The pass point for the first option is 60 points. , The next replacement process for the second option is started. Here, the leveling degree of the second option at this stage is obtained as follows with reference to FIG.

G = (3/3 + 1/2 + 1/2) /3=0.667 H = 1/2 = 0.5 W = 1/3 = 0.333 Levelness = (0.333 * 0.667 + (1-0.333) * 0.5) * 100 = 56 Therefore Although the passing score of the second option is over 60 points, the second option has not been rearranged yet, so a better order is sought, and the predetermined replacement processing routine is performed once here. .

7th step ... FIG. 3 (g) to FIG. 3 (h) Since there are 4 intervals between the 2nd and 7th steps, the bay cant road is rearranged and the 6th step is performed. The 7th row is replaced.

Eighth step ... FIG. 3 (h) to FIG. 3 (i) With respect to the second option, the peak load rearrangement is carried out because there is no longer the optimum interval 3 or more. Since the top row and the second row are continuous, this continuation is eliminated. 3 between the top row and the last issue, and below the second row
There is a gap, but here we move to the top. There are 4 intervals between the 7th and 10th steps, but even if the 7th step and the 10th step are replaced, continuity occurs again, so the 8th, 9th, and 10th steps are subject to replacement. Will be replaced.

That is, the top row and the ninth row are interchanged. Since the second option is restricted by the first option, which is a higher-order option, the rearrangement of the second option is completed by the rearrangement processing of the seventh step and the eighth step. The smoothness of this order is 94 when calculated as described above.
Becomes

Since the passing score for the second option is 50, the replacement process for the next option is started. Next, let's focus on the third option.

Step 9: Fig. 3 (i) to Fig. 3 (j) Considering the previous issue, there are 5 intervals up to the 3rd stage, but the 1st stage and the 2nd stage have higher options. Since it cannot be replaced, the peak load relocation is performed from the beginning here. Since the third stage and the fourth stage are continuous and the interval above the third stage is wider than the interval below the fourth stage, the third stage is moved. There are 4 intervals between the 7th and 10th stages, but if the 7th is replaced, it will be continuous, so 8th and 9th.
The 10th will be replaced, and the 9th, which is the center of it, will be replaced. That is, the 3rd and 9th are interchanged.

Step 10: Fig. 3 (j) to Fig. 3 (k) Considering the previously issued amount, 6 intervals have occurred up to the 4th stage, and the bay cant road is rearranged. However, since the 1st and 2nd have upper options and cannot be exchanged, the 3rd and 4th are interchanged.

11th step ... FIG. 3 (k) to FIG. 3 (l) With respect to the third option, the peak load rearrangement is performed because there is no space part of the optimum space 3 or more. Since there is an interval between the 6th and the 8th but there is an upper option in the 6th, we will move the 8th. If the 8th option has no options, there will be 4 intervals from the 7th to the 10th tiers, but the 10th tier will be replaced due to the restrictions of the higher options. That is, the 8th and 10th are interchanged.

Regarding the third option, the first option, which is a higher option
-Due to the restriction of 2 options, the sorting process from the 9th step to the 11th step completes the sorting for the 3rd option. The level of uniformity of this order is 92.

Since the passing score for the second option is 40, the replacement process for the next option is started. Next, let's focus on the fourth option.

Step 12 ... Fig. 3 (l) to Fig. 3 (m) There are 7 intervals between the 1st stage and 9th stage, but Bay Canto Road relocation due to the restriction of upper options. Can't do. Therefore, peak load relocation is performed. The 9th and 10th are consecutive, and the 9th has upper options, so the 9th will be moved. In the intervals from the second to the eighth, the third that is not subject to the constraint of the upper option is selected as the replacement target. So 10th and 3rd
The second is swapped.

Regarding the 4th option, the 1st which is the higher order option
-Because of the restriction of 2-3 options, the rearrangement processing in this step completes the rearrangement for the fourth option. The level of uniformity of this order is 53.

Since the passing score for the fourth option is 30, the replacement process for the next option is started. Next, let us focus on the fifth option.

13th step ... FIG. 3 (m) to FIG. 3 (n) Since 9 intervals have occurred from the previous issue to the 7th stage, bay cant road rearrangement is performed. First stage,
Since the second and third items cannot be interchanged due to the restrictions of the upper options, the fourth and seventh columns are interchanged.

Regarding the 5th option, due to the restriction of the upper option, it is not possible to further improve the arrangement in addition to the rearrangement processing in this step, but the level of this order is 12 points, which is below the passing point of 20 points. ing. For this reason, the rearrangement processing is performed by relaxing the restrictions of the upper options as shown below.

Step 14 ... Fig. 3 (n) to Fig. 3 (o) Since there are 6 intervals from the previous issue to the 4th stage, the constraint relaxation bay cant road relocation is performed.
Replace the 4th with the top row and set the interval from the last issue to 3
In that case, the first option becomes continuous and the levelness regarding the first option falls below the passing score, so that the fourth stage and the second stage are interchanged. In this case, the alignment of the second option will be broken, but the level will be 50 points or more, which is a passing score.

Step 15 ... Fig. 3 (o) to Fig. 3 (p) Furthermore, the 9th item is moved, but if you select the 3rd to 7th items to be replaced, the passing score will be given in any case. Since it does not meet, it chooses the 8th, which will meet all passing scores for the top options, and swaps the 9th and 8th. Its levelness is 52.

The rearrangement process for the fifth option is now completed, and the rearrangement process is finally completed because there is no next option.

In the embodiment just described, in the rearrangement process focusing on each option, the level value is calculated after Baycant load or peak load rearrangement has been performed to the end, but instead of this, rearrangement is performed. It is also possible to calculate a standard value every time a request is made and, when it exceeds the passing score, perform the rearrangement process for the next option immediately.

Further, in the example described with reference to FIG. 3, the production number is set to 10, but in an actual factory, the production number may be 100 to 1000 or more. In this type of production order planning system, the processing time increases exponentially as the number of units increases. In order to avoid this, in the present invention, the daily production volume is divided into several blocks, an independent assembly order is determined for each block, and the blocks are connected to each other to construct the assembly order for one day. To decide. In addition, when dividing a product with options evenly into blocks, as a simple and effective method to distribute the options of the product as much as possible,
As shown in Fig. 3, consider the presence or absence of the option of each product in the order of the priority of the option, for example, "10010" as a binary number, and divide the numerical value into each block in order of size. Suggested to go. At that time, the product having the preferential delivery date can be forcibly assigned to the first block.

[Brief description of drawings]

The drawings show an embodiment of an assembly sequence planning system and an assembly sequence planning method according to the present invention. FIG. 1 is an overall configuration diagram, FIG. 2 is a flowchart showing a processing procedure, and FIG.
(P) is an explanatory diagram showing how rearrangement is performed, and FIG. 4 is an explanatory diagram for leveling degree calculation. (1) …… Input section, (3) …… Output section, (4) …… Sorting processing section, (5) …… Levelness evaluation section, (51) …… Peak load evaluation section, (52)… … Variation degree evaluation section, (53)
...... Levelness calculation section, (6) …… Comparison section, (7) …… Reference value change section.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kyoichi Tsukamura, Inventor 1-247 Shikitsu East, Naniwa-ku, Osaka City, Osaka Prefecture Kubota Osaka Head Office (72) Naomi Imai Shiritsu, Naniwa-ku, Osaka City, Osaka Prefecture Higashi 1-24-247 Kubota Osaka Head Office (56) Reference JP-A-1-234142 (JP, A)

Claims (4)

(57) [Claims] 1. An assembly sequence planning system for planning the order of models to be put into an assembly line of a mixed-flow production system for assembling a product group to which various options are added, wherein a plurality of options are sequentially focused according to priority. A rearrangement processing unit 4 that rearranges the assembling order so as to evenly distribute the products to which the selected option is added to the assembly line, and the rearrangement is performed with respect to the selected option. A leveling degree evaluation unit 5 for calculating the leveling degree for the assembly sequence, and an order in which the leveling degree calculated by the leveling degree evaluation unit is compared with a preset reference value of the selected option and rearranged. Is provided with the comparison unit 6 for determining whether the above is satisfied, the rearrangement processing unit 4, the leveling degree evaluation unit 5, and the control unit 8 for controlling the comparison unit 6, and The replacement processing unit 4 replaces the peak load center with the widest bay cant load center with respect to the selected option and promotes leveling by promoting the leveling, and the option bay of interest. An assembling order planning system, comprising: bay cant road replacement means for promoting leveling by replacing a rear element of a cant road and an element at an optimal spacing position. 2. The control unit 8 activates the bay cant load replacement means as long as the bay cant load is generated, and once the bay cant load disappears, the peak load replacement means is leveled once. The assembly sequence planning system according to claim 1, wherein the rearrangement processing unit 4 is controlled so that the bay cant load replacement means is activated again when a bay cant load has occurred. 3. The control unit 8 has a high priority already used for rearrangement when the level of smoothness calculated after the rearrangement processing focusing on the selected option is below a reference value. The rearrangement processing unit 4 is controlled so that a product having a higher-order option is rearranged as a rearrangeable target as long as the level of flatness regarding the higher-order option exceeds a corresponding reference value. Or the assembly sequence planning system described in 2. 4. An assembling sequence planning method for planning the order of types to be put into an assembly line of a mixed production system for assembling a product group to which various options are added, wherein the method changes the priority from a plurality of options. According to the selection step, the step of rearranging the assembling order so that the products to which the selected option is added are evenly distributed to the assembly line, Whether the leveling step that calculates the leveling level for the sequence and the leveling level calculated by the leveling evaluation unit are compared with the preset standard value of the corresponding option and the rearranged order is satisfactory And a sorting step for determining the By replacing the center of Bay Canto Road, we will promote the leveling by promoting the leveling, and by replacing the Bay Canto Road rear element of the optional option and the element of the optimal spacing position. An assembling sequence planning method comprising: a bay cant road replacement step for promoting leveling.