MANUFACTURING OPTIMIZER BASED ON PRODUCTION AND CONSUMPTION TARGETS

• US 20130297367A1
• Filed: 03/21/2013
• Published: 11/07/2013
• Est. Priority Date: 03/21/2012
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Baramov, Lubomir
• Granted Patent: US 9,704,116 B2
• Time in Patent Office: Days
• US Class Current: 705/7.22
• CPC Class Codes: G06Q 10/06312 Adjustment or analysis of established resource schedule, e.g. resource or task levelling, or dynamic rescheduling

Abstract

An optimizer is used to help manage a process that has multiple consumption inputs with differing costs, multiple production outputs with differing sale prices and intermediates. The process may have storage capabilities for some consumption inputs, production outputs and intermediates. Further, there may be multiple production and consumption targets for the total amount of consumption inputs/production outputs, consumed/produced over a fixed period of time. The optimizer finds the most economical solution while staying in a region from which the contract target is reachable for any combination of uncertain fixed trajectories from pre-selected intervals.

Claims

1. A method of optimizing a manufacturing process having source materials, intermediates, products and media storages, the method comprising:

obtaining a model describing relations between source materials, intermediates and product flows;

setting upper and lower bounds for each of the source materials, intermediates and product flows, for storage capacities and for combinations of multiple flows;

obtaining a set of external flows constrained to specified values including at least one source whose supply has to be fully consumed and at least one product whose demand has to be fully satisfied;

determining estimates of future values of these constrained external flows as well as estimates of the upper and lower bound of those flows;

determining a set of external flows with requirements on total production or consumption for fixed periods of time, where these requirements are subject to contracts, periodically negotiated with distribution network operators;

obtaining varying costs of raw materials and products and their predictions;

computing flows of sources, intermediates and products so that all constraints are satisfied and the profit is maximized over a time horizon and, produced/consumed amounts of media under contract since the beginning of contracting period are within a region guaranteeing satisfying the contract for any combination of trajectories of fixed external flows from the pre-specified bounds;

sending the optimal future trajectories or only the next step values of the optimized flows to sub-ordinate controllers to be enforced on the process;

receiving process values to update internal states from lower control layers or operating in open loop and replacing them by estimates from the previous step; and

repeating the process of determining estimates of future values of constrained external flows and their upper and lower bounds, acquiring varying costs, computing optimal flows, sending the optimal future trajectories and receiving process values with an optimization horizon moved one time-step forward.

2. The method of claim 1 wherein a requirement of produced/consumed amounts of media under contract since the beginning of contracting period being in a region guaranteeing satisfying the contract for any combination of trajectories of fixed external flows from the pre-specified bounds is implemented as a soft constraint adding a penalty on the square of the distance of the trajectory from the region to the optimization criterion with a suitable weighting parameter.

3. The method of claim 1 where an optimization cost function for computing flows contains also a penalty for deviations of produced/consumed amounts of media during the fixed contract interval from the targets specified by the contract.

4. The method of claim 1 where an optimization cost function for computing flows contains also a penalty on squares of time increments of flows in order to achieve smooth and well posed solution.

5. The method of claim 1 wherein media flow variables are allowed to change only at specific time instants on the future time horizon and are identified as part of a blocking set.

6. The method of claim 1 wherein the optimization horizon includes more than one contracting period.

7. The method of claim 1 and further comprising initializing a state of the optimizer, wherein the state of the optimizer includes states of storages, state of fulfillment of current contracts, times of contract period ends, and historical values of optimized variables.

8. A computer readable storage device having instructions to cause a computer to implement a method of optimizing a manufacturing process having source materials, intermediates, products and media storages, the method comprising:

obtaining a model describing relations between source materials, intermediates and product flows;

obtaining upper and lower bounds for each of the source materials, intermediates and product flows, for storage capacities and for combinations of multiple flows;

obtaining a set of external flows constrained to specified values including a least one source whose supply has to be consumed and at least one product whose demand has to be satisfied;

determining estimates of future values of these constrained external flows as well as estimates of the upper and lower bound of those flows;

determining a set of external flows with requirements on total production or consumption for fixed periods of time, where these requirements are subject to contracts, periodically negotiated with distribution network operators;

obtaining varying costs of raw materials and products and their predictions;

computing flows of sources, intermediates and products so that all constraints are satisfied and the profit is maximized over a time horizon and, produced/consumed amounts of media under contract since the beginning of contracting period are within a region guaranteeing satisfying the contract for any combination of trajectories of fixed external flows from the pre-specified bounds;

sending the optimal future trajectories or only the next step values of the optimized flows to sub-ordinate controllers to be enforced on the process;

receiving process values to update internal states from lower control layers or operating in open loop and replacing them by estimates from the previous step; and

repeating the process of determining estimates of future values of constrained external flows and their upper and lower bounds, acquiring varying costs, computing optimal flows, sending the optimal future trajectories and receiving process values with an optimization horizon moved one time-step forward.

9. The computer readable storage device of claim 8 wherein a requirement of produced/consumed amounts of media under contract since the beginning of contracting period being in a region guaranteeing satisfying the contract for any combination of trajectories of fixed external flows from the pre-specified bounds is implemented as a soft constraint adding a penalty on the square of the distance of the trajectory from the region to the optimization criterion with a suitable weighting parameter.

10. The computer readable storage device of claim 8 where an optimization cost function for computing flows contains also a penalty for deviations of produced/consumed amounts of media during the fixed contract interval from the targets specified by the contract.

11. The computer readable storage device of claim 8 where an optimization cost function for computing flows contains also a penalty on squares of time increments of flows in order to achieve smooth and well posed solution.

12. The computer readable storage device of claim 8 wherein media flow variables are allowed to change only at specific time instants on the future time horizon and are identified as part of a blocking set.

13. The computer readable storage device of claim 8 wherein the optimization horizon includes more than one contracting period.

14. The computer readable storage device of claim 8 and further comprising initializing and a periodic update of a state of the optimizer, wherein the state of the optimizer includes states of storages, state of fulfillment of current contracts, times of contract period ends, and historical values of optimized variables.

15. An optimizer to optimize a manufacturing process having source materials, intermediates, products and media storages, the optimizer comprising:

an input to obtain a model describing relations between source materials, intermediates and product flows;

an input to obtain upper and lower bounds for each of the source materials, intermediates and product flows, for storage capacities and for combinations of multiple flows;

the input further obtaining a set of external flows constrained to specified values including a least one source whose supply has to be consumed and at least one product whose demand has to be satisfied;

the processor determining estimates of future values of these constrained external flows as well as estimates of the upper and lower bound of those flows;

the input further obtaining a set of external flows with requirements on total production or consumption for fixed periods of time, where these requirements are subject to contracts, periodically negotiated with distribution network operators;

the input further obtaining varying costs of raw materials and products and their predictions;

the processor computing flows of sources, intermediates and products so that all constraints are satisfied and the profit is maximized over a time horizon and, produced/consumed amounts of media under contract since the beginning of contracting period are within a region guaranteeing satisfying the contract for any combination of trajectories of fixed external flows from the pre-specified bounds;

an output to send the optimal future trajectories or only the next step values of the optimized flows to sub-ordinate controllers to be enforced on the process;

the input receiving process values to update internal states from lower control layers or operating in open loop and replacing them by estimates from the previous step; and

the processor repeating the process of determining estimates of future values of constrained external flows and their upper and lower bounds, acquiring varying costs, computing optimal flows, sending the optimal future trajectories and receiving process values with an optimization horizon moved one time-step forward.

16. The optimizer of claim 15 wherein a requirement of produced/consumed amounts of media under contract since the beginning of contracting period being in a region guaranteeing satisfying the contract for any combination of trajectories of fixed external flows from the pre-specified bounds is implemented as a soft constraint adding a penalty on the square of the distance of the trajectory from the region to the optimization criterion with a suitable weighting parameter.

17. The optimizer of claim 15 where an optimization cost function for computing flows contains also a penalty for deviations of produced/consumed amounts of media during the fixed contract interval from the targets specified by the contract.

18. The optimizer of claim 15 where an optimization cost function for computing flows contains also a penalty on squares of time increments of flows in order to achieve smooth and well posed solution.

19. The optimizer of claim 15 wherein media flow variables are allowed to change only at specific time instants on the future time horizon and are identified as part of a blocking set.

20. The optimizer of claim 15 wherein the optimization horizon includes more than one contracting period, and wherein the state of the optimizer includes states of storages, state of fulfillment of current contracts, times of contract period ends, and historical values of optimized variables.