Production planning system

• US 5,479,343 A
• Filed: 05/10/1993
• Issued: 12/26/1995
• Est. Priority Date: 11/28/1990
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Watanabe, Masahiro, Enomoto, Mitsuhiro, Tsukishima, Takahiro, Matoba, Hideaki
• Primary Examiner(s): McElheny, Jr., Donald E.
• Application Number:
  US08/059,227
• Time in Patent Office: 960 Days
• Field of Search: 364/401, 364/403, 364/468, 364/478
• US Class Current: 700/106
• CPC Class Codes: G05B 19/41865 characterised by job scheduling, process planning, material flow
• CPC Class Codes: G06Q 10/06 Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling

Abstract

In a production planning system, the explosion of a product to parts is performed by a specification check device and a design passage judgement device. An MRP calculation control device, a leadtime forecasting device, an MRP explosion calculation device, a work load calculation device and a data input/output device cooperate to estimate a shop load and to calculate a leadtime with a work load and a production capacity taken into consideration, thereby drawing up a production plan. A problem area analysis device analyzes a problematical area in the production plan to display it by graphics of the data input/output device. Various adjustment devices carry out the adjustment of the production plan through a graphic interface.

Claims

1. A production planning system comprising a data input/output device having a data input/output display and operation processing function, a leadtime forecasting device for forecasting a leadtime from a production capacity and a work load, a material requirement planning (MRP) explosion calculation device for performing an MRP calculation from the leadtime and from data for performing an MRP explosion calculation and outputting a result of the MRP calculation, a work load calculation device for calculating a work load from the result of the MRP calculation, an MRP calculation control device for controlling operation of said leadtime forecasting device, said MRP explosion calculation device and said work load calculation device, a problem area analysis device for analyzing and outputting a problematical area from an output of said MRP explosion calculation device in accordance with an instruction from said data input/output device, a production capacity adjustment device for changing a production capacity in accordance with an instruction from said data input/output device to make an output instruction to said MRP explosion calculation device, and a data retention device, whereby a possibility of execution of a production plan is judged by making a production schedule simulation through a calculation of a leadtime with a work load and a production capacity of each process being taken into consideration.

2. A production planning system according to claim 1, wherein said leadtime forecasting device includes means for determining a work load distribution from the work load and the production capacity and means for determining the leadtime from the work load distribution.

3. A production planning system according to claim 1, wherein said leadtime forecasting device includes means which is based on a pattern conversion method and is inputted with the work load and the production capacity to output the leadtime.

4. A production planning system according to claim 3, wherein said leadtime forecasting device includes means for automatically determining parameters for forecast on the basis of actual production data acquired from a manufacturing system.

5. A production planning system according to claim 1, further comprising at least one of a completion date adjustment device for adjusting a completion date of a product in accordance with an instruction from said data input/output device to make an output instruction to said MRP explosion calculation device, an alternative shop adjustment device for designating an alternative shop in accordance with an instruction from said data input/output device to make an output instruction to said MRP explosion calculation device, a job starting order adjustment device for adjusting a job starting order in accordance with an instruction from said data input/output device to make an output instruction to said MRP explosion calculation device, and a production load adjustment device for adjusting a production load in accordance with an instruction from said data input/output device to make an output instruction to said MRP explosion calculation device.

6. A production planning system according to claim 5, further comprising a specification check device for checking and correcting a client'"'"'s requested specification and a design passage judgement device for judging the necessity of a new design from the result of an output of said specification check device to perform a parts explosion, whereby a delivery date is estimated by making the production schedule simulation through the parts explosion from said client'"'"'s requested specification and the calculation of the leadtime with the work load and the production capacity of each process taken into consideration to judge whether or not the attainment of the delivery date is possible.

7. A production planning system according to claim 5, comprising a macro production load adjustment device for adjusting a macro production load, a macro production capacity adjustment device for adjusting a macro production capacity, and a daily scheduler device for formulating a daily production plan.

8. A production planning system according to claim 5, further comprising a production plan adjustment device having a countermeasure proposing function and an automatic countermeasure performing function.

9. A production planning system according to claim 8, comprising a macro production load adjustment device for adjusting a macro production load, a macro production capacity adjustment device for adjusting a macro production capacity, and a daily scheduler device for formulating a daily production plan.

10. A production planning system according to claim 5, further comprising at least one of displaying means for clarifying a problematical area from a by-period load/capacity status and a production chain for each manufacturing shop, displaying means for on-line displaying a capacity change status by the operation of said production capacity adjustment device and a production process status change associated with the capacity change, displaying means for on-line displaying a product completion date change status by the operation of said completion date adjustment device and a production process status change associated with the product completion date change, displaying means for on-line displaying an alternative shop change status by the operation of said alternative shop adjustment device and a production process status change associated with the alternative shop change, displaying means for on-line displaying a job starting order change status by the operation of said job starting order adjustment device and a production process status change associated with the job starting order change, and displaying means for on-line displaying a product production load change status by the operation of said production load adjustment device and a production process status change associated with the product production load change.

11. A production planning system according to claim 10, further comprising a production plan adjustment device having a countermeasure proposing function and an automatic countermeasure performing function.

12. A production planning system according to claim 10, further comprising a specification check device for checking and correcting a client'"'"'s requested specification and a design passage judgement device for judging the necessity of a new design from the result of an output of said specification check device to perform a parts explosion, whereby a delivery date is estimated by making the production schedule simulation through the parts explosion from said client'"'"'s requested specification and the calculation of the leadtime with the work load and the production capacity of each process taken into consideration to judge whether or not the attainment of the delivery date is possible.

13. A production planning system according to claim 10, comprising a macro production load adjustment device for adjusting a macro production load, a macro production capacity adjustment device for adjusting a macro production capacity, and a daily scheduler device for formulating a daily production plan.

14. A production plan adjusting system comprising:

a problem area analysis device for analyzing the distribution of each of a capacity and a load at each shop in a production plan on the basis of given production plan data and constraint condition data and detecting, in the case where an overload state in which a load exceeds a capacity is generated, a problematical area of generation of the overload state to produce analysis data;

a constraint relaxation judgement device for judging whether or not a plan in an inexecutable state is adjustable within a range of constraint conditions including the upper and lower limits of a total working time in a plan period and the upper and lower limits of a daily working time;

an efficient constraint relaxation selection device for selecting, when the adjustment within the range of constraint conditions is determined as being impossible, the kind of relaxation of the constraint conditions for effecting the cancellation of said overload state;

a constraint relaxation adjustment formulation device for formulating a first adjustment method based on the relaxation of the constraint conditions;

an efficient in-constraint adjustment selection device for selecting, when the adjustment within the range of constraint conditions is determined as being possible, a second adjustment method for effecting the cancellation of said overload state within the range of constraint conditions;

an in-constraint adjustment formulation device for formulating said second adjustment method within the range of constraint conditions; and

an adjustment formulation control device for controlling the sequence of operations of said problematical area analysis device, said constraint relaxation judgement device, said efficient constraint relaxation selection device and said efficient in-constraint adjustment selection device;

whereby there is provided a function by which in order to turn an inexecutable production plan into an executable production plan, the allotted state of each of a capacity and a load at each shop is analyzed to make the analysis of a problematical area, thereby judging the necessity of the relaxation of the constraint conditions, and a production plan adjusting method with the relaxation of the constraint conditions taken into consideration and a production plan adjusting method within the range of constraint conditions are respectively formulated in the case where the relaxation of the constraint conditions is determined as being necessary and in the case where the relaxation of the constraint conditions is determined as being unnecessary.

15. A production plan adjusting system according to claim 14, wherein said data input/output device has a displaying function and displays either said production plan data, said constraint condition data or said analysis data.

16. A production plan adjusting system according to claim 14, wherein said data input/output device has a displaying function and displays either output data of said constraint relaxation adjustment formulation device, output data of said efficient constraint relaxation selection device, output data of said efficient in-constraint adjustment selection device or output data of said in-constraint adjustment formulation device.

17. A production plan adjusting system according to claim 14, wherein said problematical area analysis device includes means for forming a load accumulation graph as the accumulation of daily load amounts and a capacity accumulation graph as the accumulation of daily capacity amounts for each shop from the heaped state of a load and the heaped state of a capacity for each shop, means for forming the earliest capacity accumulation graph for each shop in the constraint conditions, said earliest capacity accumulation graph being a capacity accumulation graph formed so that the accumulation of all capacity amounts is completed earliest on a time axis, means for forming the latest load accumulation graph and the latest capacity accumulation graph for each shop in the constraint conditions, said latest load accumulation graph being a load accumulation graph formed so that the accumulation of all load amounts is completed latest on the time axis and said latest capacity accumulation graph being a capacity accumulation graph formed so that the accumulation of all capacity amounts is completed latest on a time axis, means for forming the earliest capacity accumulation graph for each shop group on the basis of the earliest capacity accumulation graph for each shop, means for forming the latest load accumulation graph for each shop group on the basis of the latest load accumulation graph for each shop, means for comparing the earliest capacity accumulation graph and the latest load accumulation graph for each shop group to determine a planned date of interest and an overload amount at that time, and means for comparing the earliest capacity accumulation graph and the latest load accumulation graph for each shop to determine a planned date of interest and an overload amount at that time.

18. A production plan adjusting system according to claim 17, wherein said means for forming the earliest capacity accumulation graph for each shop within the constraint conditions includes means for combining a by-day upper limit capacity addition accumulation graph formed by the addition of upper limit capacities by days toward the future from the first day of a production plan period at a shop of interest and a by-day lower limit capacity subtraction accumulation graph formed by the subtraction of lower limit capacities by days from an upper limit capacity in the production plan period heaped on the last day toward the past from the last day of the production plan period to form the earliest capacity accumulation graph in the shop of interest.

19. A production plan adjusting system according to claim 14, wherein said constraint relaxation judgement device includes means for judging whether or not there exists a shop group in which an overload state is generated, means for judging whether or not a shop group with a overload state generated is a shop group for the final assembling process, means for judging whether or not a planned date on which an overload state is generated at a certain shop group and an overload amount at that time can be removed by a shop change for a job in the certain shop group, and means for judging whether or not a planned date on which an overload state is generated at a certain shop group and an overload amount at that time can be removed by a shop change for a job in a shop group in a stream lower than the certain shop group.

20. A production plan adjusting system according to claim 19, wherein said means for judging whether or not a planned date on which an overload state is generated at a certain shop group and an overload amount at that time can be removed by a shop change for a job in the certain shop group, includes means for determining an acceptable load amount for each shop in the certain shop group from a by-day upper limit capacity addition accumulation graph formed by the accumulation of upper limit capacities by days for that shop in accordance with the lapse of time and a load accumulation graph formed by the accumulation of loads by days for that shop in accordance with the lapse of time, said acceptable load amount being a load amount capable of being accepted at that shop, and means for comparing an overload amount when an overload state is generated and the acceptable load amount at each shop to judge whether or not the removal of the overload amount is possible by a shop change for a job in the certain shop group.

21. A production plan adjusting system according to claim 14, further comprising an undertaken in-constraint adjustment determination device having a function of determining an adjustment method to be undertaken on the basis of data of efficient in-constraint adjustment which is output data of said efficient in-constraint adjustment selection device.

22. A production plan adjusting system according to claim 21, wherein said undertaken in-constraint adjustment determination device includes means for selecting at least one adjustment method to be formulated among at least one or more adjustment methods which are in a plurality of adjustment methods each provided with a predetermined priority and which exist within the range of constraint conditions.

23. A production plan adjusting system according to claim 21, wherein said data input/output device has a displaying function and displays output data of said undertaken in-constraint adjustment determination device.

24. A production plan adjusting system according to claim 14, further comprising an undertaken constraint relaxation determination device having a function of determining the contents of the constraint condition relaxation to be undertaken on the basis of data of efficient constraint relaxation which is output data of said efficient constraint relaxation selection device.

25. A production plan adjusting system according to claim 24, wherein said undertaken constraint relaxation determination device includes means for selecting at least one among a plurality of candidate sets each of which includes one set of a constraint condition in the production plan and the content of relaxation of that constraint condition and is provided with a predetermined priority.

26. A production plan adjusting system according to claim 24, wherein said data input/output device has a displaying function and displays output data of said undertaken constraint relaxation determination device.

27. A production plan adjusting system according to claim 24, further comprising an undertaken in-constraint adjustment determination device having a function of determining an adjustment method to be undertaken on the basis of data of efficient in-constraint adjustment which is output data of said efficient in-constraint adjustment selection device.

28. A production plan adjusting system according to claim 27, wherein said undertaken in-constraint adjustment determination device includes means for selecting at least one adjustment method to be formulated among at least one or more adjustment methods which are in a plurality of adjustment methods each provided with a predetermined priority and which exist within the range of constraint conditions.

29. A production plan adjusting system according to claim 27, wherein said data input/output device has a displaying function and displays output data of said undertaken in-constraint adjustment determination device.