STACK HANDLING OPERATION METHOD, SYSTEM, AND COMPUTER PROGRAM

• US 20140074538A1
• Filed: 09/24/2013
• Published: 03/13/2014
• Est. Priority Date: 09/11/2012
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hama, Toshiyuki, Yanagisawa, Hiroki, Yoshizumi, Takayuki
• Granted Patent: US 9,495,654 B2
• Time in Patent Office: Days
• US Class Current: 705/7.23
• CPC Class Codes: B66C 1/00 Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles fastening to cables or ropes F16G11/00
• CPC Class Codes: B66C 23/58 arranged to carry out a desired sequence of operations automatically, e.g. hoisting followed by luffing and slewing
• CPC Class Codes: G06Q 10/063 Operations research, analysis or management
• CPC Class Codes: G06Q 10/06315 Needs-based resource requirements planning or analysis

Abstract

A method for searching transition routes from an initial state of a plurality of stackable items to a target state by a computer at predetermined conditions includes connecting between transitionable states at an edge by a single handling operation transitioning from the initial state to the target state, to generate a state space graph; evaluating a lower bound of handling operation cost from a certain state to the target state, based on both the stacking sequence of the plurality of items in the certain state and the stacking sequence of the plurality of items in the target state; and searching a route from the initial state to the target state where the handling operation cost is minimal on the state space graph using a heuristic search algorithm based on the lower bound.

Claims

1. A method for searching transition routes from an initial state of a plurality of stackable items to a target state by a computer at predetermined conditions, comprising:

connecting between transitionable states at an edge by a single handling operation transitioning from the initial state to the target state, to generate a state space graph;

evaluating a lower bound of handling operation cost from a certain state to the target state, based on both the stacking sequence of the plurality of items in the certain state and the stacking sequence of the plurality of items in the target state; and

searching a route from the initial state to the target state where the handling operation cost is minimal on the state space graph using a heuristic search algorithm based on the lower bound.

2. The method according to claim 1, wherein the lower bound is evaluated in the evaluation based on the number of points where the stacking sequence of the plurality of items in the certain state differs from the stacking sequence of the plurality of items in the target state.

3. The method according to claim 2, wherein a counting method for the number of different points is modified, based on whether the target state is a state where the plurality of items are stacked to a specific location from a plurality of locations, or whether the target state is a state where the plurality of items are stacked to an arbitrary location of the plurality of locations.

4. The method according to claim 1, further comprising recording, on a recording means of a computer, a stacking sequence where a fewer number of items than the plurality of items can be taken, and the optimal section handling operation cost thereof, prior to the evaluating, wherein the lower bound is calculated based on the section handling operation cost in the evaluating.

5. The method according to claim 4, wherein the evaluating comprises:

splitting the plurality of items in the certain state into a plurality of sections;

reading the section handling operation cost that corresponds to each split section from the recording means of the computer; and

calculating the lower bound, based on the sum of the section handling operation costs.

6. The method according to claim 5, wherein calculating the lower bound is based on the connectivity between the split sections.

7. The method according to claim 5, wherein more items are included in one section, within the extent of being recorded in the recording means of the computer.

8. The method according to claim 1, wherein the handling operation cost is the number of operations.

9. The method according to claim 1, wherein the heuristic search algorithm is A* (A star) algorithm.

10. The method according to claim 9, wherein the lower bound is the evaluation value of the heuristic function.

11. The method according to claim 1, wherein the predetermined condition is a condition that restricts stacking of the plurality of items, and wherein the generating the state space graph is based on a condition that restricts the stacking.

12. The method according to claim 1, wherein the predetermined condition is a condition that restricts the number and weight of the movable items by one operation, and wherein the generating the state space graph is based on a condition that restricts the number or the weight.

13. The method according to claim 1, wherein the predetermined condition is a condition that restricts overall height of the stackable items, and wherein the generating the state space graph generates is based on the condition that restricts the overall height.

14. The method according to claim 1, wherein the items are steel products after a steel manufacturing process and before a hot rolling process;

the initial state is a stacking state of the plurality of steel products after the steel manufacturing process; and

the target state is the stacking state of the plurality of steel products suitable for the hot rolling process.

15. The method according to claim 14, wherein the operation is a crane operation, and further comprising outputting a route where the handling operation cost is minimal, obtained by the searching, as the crane operation sequence.

16. The method according to claim 14, further comprising outputting the handling operation cost obtained by the searching to a steel production scheduler.

17. The method according to claim 14, further comprising outputting the handling operation cost obtained by the searching, by responding to a query that includes the initial state and the target state from the steel production scheduler.

18. A computer program that executes the method according to claim 1 in the computer when executed by the computer.

19. The computer program according to claim 18 that functions as a part of the steel production scheduler.