Exception handling in manufacturing systems combining on-line planning and predetermined rules

• US 20050278050A1
• Filed: 05/27/2004
• Published: 12/15/2005
• Est. Priority Date: 05/27/2004
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: Ruml, Wheeler, Lofthus, Robert M., Fromherz, Markus P.J., Webster, Marc W., Root, Ronald J.
• Granted Patent: US 7,043,321 B2
• Time in Patent Office: Days
• US Class Current: 700/100
• 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
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A method for performing exception handling operates within a computer controlled multi-step production system for producing objects. The system includes a system controller, within which reside a planner/scheduler and module controller(s). The system controller receives a stream of object specifications for objects to be produced including the jobs to which they belong. The planner/scheduler plans and schedules the jobs incrementally, and the system controller sends commands to the module controller(s) directing production of the planned and scheduled objects by production system modules. The method includes receiving notice in the system controller of a problem situation present within the multi-step production system and halting planning for the production of subsequent objects. Plans are canceled plans for all objects that have not begun production, and all objects affected by the problem situation are marked as bad objects. The system controller planned exception handling/recovery or module controller directed exception handling/recovery is applied and normal operation is resumed.

Claims

1. A method for performing exception handling within a computer controlled multi-step production system for producing objects, wherein said system includes a system controller, within which reside a planner/scheduler and at least one module controller, wherein the system controller receives a stream of object specifications for objects to be produced including the jobs to which they belong, wherein the planner/scheduler plans and schedules the jobs incrementally, and wherein the system controller sends commands to the at least one module controller directing production of the planned and scheduled objects by production system modules, the method comprising:

receiving notice in the system controller of a problem situation present within the multi-step production system, wherein said problem situation includes at least one member selected from the group consisting of equipment operational issues and bad objects, such as misproduced, out-of-order, or missing objects;

halting planning for the production of subsequent objects;

canceling plans for all objects that have not begun production;

marking all objects affected by said problem situation as bad objects;

applying at least one of system controller planned exception handling/recovery or module controller directed exception handling/recovery; and

resuming normal operation.

2. The method for performing exception handling within a computer controlled multi-step production system according to claim 1, wherein module controller directed exception handling/recovery comprises:

communicating from the system controller to the at least one module controller the identity of objects considered bad;

executing at least one module controller predetermined recovery action for the objects considered bad, wherein said predetermined recovery action are modeled and made known to the system controller together with information about the conditions for which the actions will be taken in a particular problem situation prior to the start of production; and

planning and scheduling by the system controller of the complement of the objects that will be produced correctly by said at least one predetermined recovery action.

3. The method for performing exception handling within a computer controlled multi-step production system according to claim 2, wherein said predetermined recovery action comprises execution of a single planned action.

4. The method for performing exception handling within a computer controlled multi-step production system according to claim 2, wherein said predetermined recovery action comprises execution of any of a set of alternative actions including disposal of said bad object from the production system or repair of said bad object.

5. The method for performing exception handling within a computer controlled multi-step production system according to claim 4, wherein disposal of said bad object comprises ejection by a production system module.

6. The method for performing exception handling within a computer controlled multi-step production system according to claim 4, wherein disposal of said bad object comprises direction of said bad object along an alternate route through the production toward a disposal point.

7. The method for performing exception handling within a computer controlled multi-step production system according to claim 4, wherein repair of said bad object comprises adjusting an incorrect orientation on the production line.

8. The method for performing exception handling within a computer controlled multi-step production system according to claim 1, wherein said system controller planned exception handling/recovery comprises:

specifying by the system controller the recovery plan based on a model of the production system, wherein said model includes the capabilities and default exception handling actions of each module in the production system;

informing the at least one module controller of the identity of said bad objects;

informing the affected at least one module controller of said recovery plan for said bad objects; and

computing the plans and canceling and resending the plans for objects whose plans have been changed.

9. The method for performing exception handling within a computer controlled multi-step production system according to claim 8, further including specifying which action is to be taken by each production module upon encountering each said bad object.

10. The method for performing exception handling within a computer controlled multi-step production system according to claim 8, wherein recovery of said bad objects comprises repair of said bad objects or disposal of said bad objects.

11. The method for performing exception handling within a computer controlled multi-step production system according to claim 1, wherein the production system further comprises a coordinator module interfacing with the system controller and the at least one module controller.

12. The method for performing exception handling within a computer controlled multi-step production system according to claim 1, wherein the production system comprises a printing system.

13. The method for performing exception handling within a computer controlled multi-step production system according to claim 1, wherein the production system comprises a manufacturing system.

14. The method for performing exception handling within a computer controlled multi-step production system according to claim 1, wherein the production system comprises an assembly line.

15. A system for performing exception handling within a computer controlled multi-step production system for producing objects, wherein said system includes a system controller, within which reside a planner/scheduler and at least one module controller, wherein the system controller receives a stream of object specifications for objects to be produced including the jobs to which they belong, wherein the planner/scheduler plans and schedules the jobs incrementally, and wherein the system controller sends commands to the at least one module controller directing production of the planned and scheduled objects by production system modules, the system comprising:

means for receiving notice within the system controller of a problem situation present within the multi-step production system, wherein said problem situation includes at least one member selected from the group consisting of equipment operational issues and bad objects, such as misproduced, out-of-order, or missing objects;

means for halting planning for the production of subsequent objects;

means for canceling plans for all objects that have not begun production;

means for marking all objects affected by said problem situation as bad objects;

means for applying at least one of system controller planned exception handling/recovery or module controller directed exception handling/recovery; and

means for resuming normal operation.

16. The system for performing exception handling within a computer controlled multi-step production system according to claim 15, wherein module controller directed exception handling/recovery comprises:

means for communicating from the system controller to the at least one module controller the identity of objects considered bad;

means for executing at least one module controller predetermined recovery action for the objects considered bad, wherein said predetermined recovery action are modeled and made known to the system controller together with information about the conditions for which the actions will be taken in a particular problem situation prior to the start of production; and

means for planning and scheduling by the system controller of the complement of the objects that will be produced correctly by said at least one predetermined recovery action.

17. The system for performing exception handling within a computer controlled multi-step production system according to claim 16, wherein said predetermined recovery action comprises execution of a single planned action.

18. The system for performing exception handling within a computer controlled multi-step production system according to claim 16, wherein said predetermined recovery action comprises execution of any of a set of alternative actions including disposal of said bad object from the production system or repair of said bad object.

19. The system for performing exception handling within a computer controlled multi-step production system according to claim 18, wherein disposal of said bad object comprises ejection by a production system module.

20. The system for performing exception handling within a computer controlled multi-step production system according to claim 18, wherein disposal of said bad object comprises direction of said bad object along an alternate route through the production toward a disposal point.

21. The system for performing exception handling within a computer controlled multi-step production system according to claim 18, wherein repair of said bad object comprises adjusting an incorrect orientation on the production line.

22. The system for performing exception handling within a computer controlled multi-step production system according to claim 15, wherein said system controller planned exception handling/recovery comprises:

means for specifying by the system controller the recovery plan based on a model of the production system, wherein said model includes the capabilities and default exception handling actions of each module in the production system;

means for informing the at least one module controller of the identity of said bad objects;

means for informing the affected at least one module controller of said recovery plan for said bad objects; and

means for computing the plans and canceling and resending the plans for objects whose plans have been changed.

23. The system for performing exception handling within a computer controlled multi-step production system according to claim 22, further including specifying which action is to be taken by each production module upon encountering each said bad object.

24. The system for performing exception handling within a computer controlled multi-step production system according to claim 22, wherein recovery of said bad objects comprises repair of said bad objects or disposal of said bad objects.

25. The system for performing exception handling within a computer controlled multi-step production system according to claim 15, wherein the production system further comprises a coordinator module interfacing with the system controller and the at least one module controller.

26. The system for performing exception handling within a computer controlled multi-step production system according to claim 15, wherein the production system comprises a printing system.

27. The system for performing exception handling within a computer controlled multi-step production system according to claim 15, wherein the production system comprises a manufacturing system.

28. The system for performing exception handling within a computer controlled multi-step production system according to claim 15, wherein the production system comprises an assembly line.

29. An article of manufacture comprising a computer usable medium having computer readable program code embodied in said medium which, when said program code is executed by said computer causes said computer to perform method steps for performing exception handling within a computer controlled multi-step production system for producing objects, wherein said system includes a system controller, within which reside a planner/scheduler and at least one module controller, wherein the system controller receives a stream of object specifications for objects to be produced including the jobs to which they belong, wherein the planner/scheduler plans and schedules the jobs incrementally, and wherein the system controller sends commands to the at least one module controller directing production of the planned and scheduled objects by production system modules, the method comprising:

receiving notice within the system controller of a problem situation present within the multi-step production system, wherein said problem situation includes at least one member selected from the group consisting of equipment operational issues and bad objects, such as misproduced, out-of-order, or missing objects;

halting planning for the production of subsequent objects;

canceling plans for all objects that have not begun production;

marking all objects affected by said problem situation as bad objects;

applying at least one of system controller planned exception handling/recovery or module controller directed exception handling/recovery; and

resuming normal operation.