Production control system

• US 5,237,508 A
• Filed: 04/10/1991
• Issued: 08/17/1993
• Est. Priority Date: 08/10/1989
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Suzuki, Shozo, Furukawa, Satomi, Seki, Yuuji, Ohide, Hiroshi
• Primary Examiner(s): Smith, Jerry
• Assistant Examiner(s): Gordon, Paul
• Application Number:
  US03/401,033
• Time in Patent Office: 860 Days
• Field of Search: 364/468, 364/469, 364/138, 364/474.11, 364/140, 364/401, 364/131, 364/550, 364/478
• US Class Current: 700/100
• CPC Class Codes: G05B 19/41865 characterised by job scheduling, process planning, material flow
• CPC Class Codes: G05B 2219/31379 Master monitors controllers, updates production progress, allocates resources
• CPC Class Codes: G05B 2219/32252 Scheduling production, machining, job shop
• CPC Class Codes: G05B 2219/32292 Large, medium and fine schedule, with feedback from fine to large
• CPC Class Codes: G05B 2219/32297 Adaptive scheduling, feedback of actual proces progress to adapt schedule
• CPC Class Codes: G05B 2219/32301 Simulate production, process stages, determine optimum scheduling rules
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

What is disclosed is a production control system for dealing with the demand of producing many kinds of products in small quantities within a short delivery period by improving productivity of production lines and unmanned operation of the lines. The production control system has a plurality of facilities (1) including parts mounters (14) for processing products through processes, cell controllers (2) for controlling the facilities, a line control system (3) for centrally controlling all the cell controllers, and a transporting unit (4) controlled by the line control system to transport the products between the facilities. The line control system (3) comprises a unit (401) for preparing a detailed execution schedule by considering, in real time, a schedule of a relatively short period extracted from a schedule of a relatively long period, half-finished conditions of the products in a line, and actual events. The line control system controls the cell controllers, parts mounters, and transporting unit according to the prepared execution schedule.

Claims

1. A production control system, comprising:

a plurality of facilities including parts mounters for processing a plurality of products using a plurality of processes;

a plurality of cell controllers controlling said facilities;

transporting means for transporting the products between said facilities; and

a line control system including means for preparing a first schedule of a relatively short period extracted from a second schedule of a relatively long period, and an execution schedule by considering, in real time, finishing conditions of the products in a line, and actual events, said line control system controlling said cell controllers, said parts mounters, and said transporting means according to the execution schedule.

2. A production control system as set forth in claim 1, wherein said line control system further comprises:

means for analyzing an alarm from said facilities detected by one of said cell controllers as one of the actual events; and

means for automatically rearranging the execution schedule excluding said facilities issuing the alarm when analysis of said alarm indicates that said facilities cannot be restored in a predetermined time and for indicating that the execution schedule must be rearranged when analysis of the alarm indicates that a cause of the alarm is unknown.

3. A production control system as set forth in claim 1, wherein preparation work for changing process conditions between the processes requires a certain amount of time, and wherein said line control system further comprises:

a priority ranking table ranking the processes in order of a total processing time of each of the processes and storing the ranking of the processes;

a sorting table grouping the products in a grouped result according to the process conditions in each of the processes and storing the grouped result; and

means for arranging the grouped result and products so that adjacent ones of groups in the grouped result and the products have a maximum number of identical process conditions, the grouping organized in descending order of the total processing time to minimize a number of preparations, thereby determining a product feeding sequence and the execution schedule.

4. A production control system as set forth in claim 3, wherein when an urgent article handling request is one of the actual events, the urgent article is fed first in a corresponding one of the processes.

5. A production control system as set forth in claim 3, wherein, when an urgent article handling request is one of the actual events, the execution schedule is prepared giving a delivery period of the urgent article a shorter margin than that given to a delivery period of an article not having an urgent article handling request.

6. A production control system as set forth in claim 5, further comprising means for generating an alarm in real time for workers in an assembling line of said production control system.

7. A production control system as set forth in claim 1, wherein said line control system comprises

schedule/result comparing means for comparing an executing schedule with results from said parts mounters, and

means for generating an alarm after detecting a deviation in the comparison results of said schedule/result comparing means.

8. A production control system as set forth in claim 1, further comprising:

a free time managing table managing a free time of each process;

a process history table providing a history of jobs to be processed through each process; and

a table of shift time storing a shift time between the processes, each job having a process route and man-hours for each process, the execution schedule being prepared by recursively simulating a start time, end time, and delivery time to the next process of each of the jobs for each process according to the process route.

9. A production control system as set forth in claim 1,

wherein said facilities are grouped in sets, each having a product detecting portion for detecting whether a product is present at a product feeding port of a corresponding set of said facilities, and

wherein said line control system comprises:

a schedule managing table storing a work schedule of each set of said facilities, and

a process route managing table storing a process route and a present location of each product, and when said product detecting portion detects that the feeding port of the corresponding set of said facilities is empty, said line control system refers to said process route managing table to determine a facility having a next product to be transported to one of said facilities, and issues a products transporting instruction to said transporting means.

10. A product control system as set forth in claim 1, wherein said facilities are grouped in sets, and wherein each of the sets of said facilities comprises:

a product detecting portion detecting whether a product is present at a product feeding port of a corresponding set of said facilities, and

transport request generating means for generating a request for transporting one of the products to be received next when said product detecting portion detects no product at the feeding port associated therewith, the product detecting portion confirming whether any of the products are present at the feeding port of said plurality of facilities, and if no product is present, said transport request generating means generating a request for transporting a product to be received next,

wherein said line control system collates contents of the transport request generated by said transport request generating means with processed products to produce a result of collation, and if one of the products coincides with the result of the collation, issues a transportation instruction for the one of the products to said transporting means.

11. A production control system as set forth in claim 1,

wherein said parts mounter comprises a parts unloaded state detecting means for detecting that parts are not loaded and issuing, when a shortage of the parts occurs during processing of the products, shortage information to a corresponding cell controller for controlling said parts mounter having a shortage of parts,

wherein each cell controller comprises means for informing said line control system of the shortage information, and

wherein said line control system comprises a shortage managing memory for storing names of the parts of which there is a shortage according to the shortage information.

12. A production control system as set forth in claim 11, wherein each cell controller comprises:

means for receiving input numerical control data from said line control system indicating a relationship between parts and a position of a channel to which the parts are mounted in said parts mounter,

means for automatically generating new numerical control data by updating the input numerical control data upon receiving the shortage information, and

means for sending the new numerical control data to said parts mounter.

13. A production control system as set forth in claim 11, wherein each cell controller comprises:

means for receiving input numerical control data from said line control system indicating a relation between parts and a position of a channel to which said parts are mounted in said parts mounter,

means for automatically generating new numerical control data by updating the input numerical control data upon receiving the shortage information to relate the parts of which there is a shortage with another channel containing the same parts, and

means for the new numerical control data to said parts mounter.

14. A production control system as set forth in claim 1, wherein each of said facilities comprises:

a parts shelf for storing parts, said parts shelf including means for indicating a stored position of each part as and when requested, and a parts setting portion for taking parts out of said parts shelf, said parts setting portion including

means for indicating a relation of the parts, and

channels for storing the products as and when requested, and

wherein said line control system includes means for indicating positions of parts in said parts shelf and positions of the channels in said parts setting portion when a relationship between the parts to be fed and the channels is to be changed in any of said facilities.

15. A production control system as set forth in claim 1, wherein said facilities are grouped in sets, and wherein said line control system comprises a numerical control data memory for each set of said facilities for storing numerical control data related to the parts to be mounted, at least two of the sets of said facilities having identical specifications and being controlled by identical numerical control data, and

means for reflecting a correction made on the numerical control data of one set of said facilities having identical specifications in another set of said facilities having the identical specifications.

16. A production control system as set forth in claim 1, wherein said facilities are grouped in sets, and wherein said line control system comprises a dump file for dumping a work terminated state when work is terminated partway through a product lot to end a system operation, thereby enabling work to be restarted from the work terminated state held in said dump file after said production control system is started again.

17. A production control system as set forth in claim 1, wherein said facilities are grouped in sets, and wherein said line control system comprises means for collecting conditions of each set of the facilities through said cell controllers and informing said cell controllers of conditions of all the facilities.

18. A production control system as set forth in claim 1, wherein said line control system comprises:

a logging file for storing work results collected in real time, and

means for reproducing contents of the logging file on a monitor screen.

19. A production control system as set forth in claim 1, wherein said line control system comprises:

means for managing progress of production of products, and

means for displaying a location of a product on a graphic screen after a name of the product is input.