Method and system for decanting a plurality of items supported on a transport structure at one time with a picking tool for placement into a transport container
A method and system for decanting a plurality of substantially identical target items in a topmost layer of target items supported on a transport structure at one time with a picking tool for placement into a transport container are provided. The method includes the steps of providing a ranked configuration which describes the location and orientation of all items in the topmost layer and identifying a set of all legal picks of multiple items from the topmost layer based on the size and shape of the picking tool and the size and shape of the transport container. The method also includes the step of grouping the legal picks into equivalence classes. Each equivalence class contains a subset of items from the ranked configuration.
1. A method of decanting a plurality of substantially identical target items in a topmost layer of target items supported on a transport structure at one time with a picking tool for placement into a transport container, the method comprising the steps of:
providing a ranked configuration which describes the location and orientation of all items in the topmost layer;
identifying a set of all legal picks of multiple items from the topmost layer based on the size and shape of the picking tool and the size and shape of the transport container; and
grouping the legal picks into equivalence classes, each equivalence class containing a subset of items from the ranked configuration.
2. The method as claimed in claim 1 , further comprising the step of ranking the equivalence classes based on the number of members in the classes.
3. The method as claimed in claim 1 , wherein each target item is a box-like object such as a box or a large bag.
4. The method as claimed in claim 1 , wherein the transport structure is a pallet.
5. The method as claimed in claim 1 , wherein the target container is a decanting tote.
6. The method as claimed in claim 1 , wherein the set of all legal picks of multiple items from the set of items on the topmost layer is computed via a three-dimensional convolution between the configuration of items on the topmost layer and the shape of the picking tool, wherein indices {h, v, a} of the convolution correspond to hypotheses regarding the position and orientation of the picking tool.
7. The method as claimed in claim 1 , wherein two legal picks are placed into the same equivalence class when the picks select the same item.
8. The method as claimed in claim 1 , wherein the equivalence classes are ranked according to the number of items selected by each member of the equivalence class.
9. The method as claimed in claim 1 , wherein the equivalence classes are ranked first, according to the number of items selected in the equivalence class then, in case of ties, the tied equivalence classes are further ranked by the distance an autonomous manipulator would move to pick the items in the equivalence class and deposit the items at their destination.
10. The method as claimed in claim 8 , wherein the step of identifying identifies the subset of multiple items to be picked at one time by the picking tool and is performed by randomly selecting one of the equivalence classes from the equivalence classes ranked highest.
11. The method as claimed in claim 10 , wherein the step of identifying identifies the subset of multiple items to be picked at one time by the picking tool and is performed by selecting the highest ranked equivalence class in the ranking.
12. A system for decanting a plurality of substantially identical target items in a topmost layer of target items supported on a transport structure at one time with a picking tool for placement into a transport container, the system comprising:
a memory device configured to store a ranked configuration which describes the location and orientation of all items in the topmost layer; and
at least one processor configured to identify a set of all legal picks of multiple items from the topmost layer based on the size and shape of the picking tool and the size and shape of the transport container, wherein the at least one processor is also configured to group the legal picks into equivalence classes, each equivalence class containing a subset of items from the ranked configuration.
13. The system as claimed in claim 12 , wherein the at least one processor is configured to rank the equivalence classes based on the number of members in the classes.
14. The system as claimed in claim 12 , wherein each target item is a box-like object such as a box or a large bag.
15. The system as claimed in claim 12 , wherein the transport structure is a pallet.
16. The system as claimed in claim 12 , wherein the target container is a decanting tote.
17. The system as claimed in claim 12 , further comprising an autonomous manipulator attached to the picking tool, the picking tool and the manipulator being configured to pick the items from the transport structure based on the ranked configuration and to place the picked items into the transport container.
18. The system as claimed in claim 17 , wherein the autonomous manipulator is a vision-guided robot configured to pick and place the items.