System for topping and tailing lettuce heads using a camera-guided servo-controlled water knife
View Patent ↗A system for trimming a lettuce head using a digital imaging system and cutting mechanism. The lettuce head is conveyed between a lower feed conveyor and an upper feed conveyor that is disposed a fixed distance over and substantially aligned with a lower feed conveyor. The digital imaging system is configured to capture an image of the lettuce head and determine a cutting profile using the image. The cutting mechanism is disposed over the lower feed conveyor and includes: a servo motor mechanically coupled to a drive shaft; an armature with a pivot end mounted to the drive shaft and a sweep end disposed a radial distance from the pivot end; a cutting nozzle, mounted to the sweep end of the armature, configured to trim the lettuce head; and servo-control circuitry configured to articulate the cutting nozzle through a cutting arc based on the cutting profile.
1. A system for trimming a whole lettuce head having a top end and a tail end, the system comprising:
a lower feed conveyer configured to convey the lettuce head, the lower feed conveyor having an input end and an output end;
an upper feed conveyor disposed a fixed distance over and substantially aligned with the lower feed conveyor to convey the lettuce head disposed between the lower and upper feed conveyors;
a digital imaging system disposed over the lower feed conveyor a fixed distance from the input end of the lower feed conveyor, wherein the digital imaging system is configured to capture an image of the lettuce head and determine a top-cutting profile using the image; and
a top-cutting mechanism disposed over the lower feed conveyor between the digital imaging system and the output end of the lower feed conveyor, comprising:
a first servo motor mechanically coupled to a first drive shaft;
a first armature with a pivot end and a sweep end, wherein
the sweep end is disposed a radial distance from the pivot end,
the first armature is configured to sweep through a top-cutting arc substantially parallel to the lower feed conveyor, and
the pivot end is mechanically coupled and axially aligned with the first drive shaft;
a first cutting nozzle configured to trim the lettuce head, wherein the first cutting nozzle is mounted to the sweep end of the first armature; and
servo-control circuitry configured to articulate the first cutting nozzle through at least one top-cutting arc based on the top-cutting profile to trim the top end of the lettuce head, wherein the first cutting nozzle is operated while the first armature is being articulated through the at least one top-cutting arc wherein the digital imaging system is configured to determine a tail-cutting profile using the image; the system further comprising: a tail-cutting mechanism disposed over the lower feed conveyor and near the top-cutting mechanism, the tail-cutting mechanism comprising: a second servo motor mechanically coupled to a second drive shaft; a second armature with a pivot end and a sweep end, wherein the sweep end is disposed a radial distance from the pivot end, the second armature is configured to sweep through a tail-cutting arc substantially parallel to the lower feed conveyor, and the pivot end is mechanically coupled and axially aligned with the second drive shaft; and a second cutting nozzle to cut the lettuce head, wherein the second cutting nozzle is mounted to the sweep end of the second armature, wherein the servo-control circuitry is configured to articulate the second cutting nozzle through at least one tail-cutting arc based on the tail-cutting profile to trim the tail end of the lettuce head, wherein the second cutting nozzle is operated while the second armature is being articulated through the at least one tail-cutting arc.
2. The system of claim 1 , wherein the lower feed conveyor is configured to convey the lettuce head under the top-cutting mechanism as the first cutting nozzle is articulated through the top-cutting arc to produce a variable-radius cut across the top end of the lettuce head.
3. The system of claim 2 , wherein the variable-radius cut corresponds to the top-cutting profile.
4. The system of claim 1 , wherein the digital imaging system determines the top-cutting profile by determining a top-edge profile of the top end of the lettuce head and determining an offset from the top-edge profile.
5. The system of claim 4 , wherein the top-cutting profile is a fixed distance from and follows the top-edge profile.
6. The system of claim 4 , wherein the top-cutting profile is a fixed distance from the top-edge profile and the top-cutting profile is a predetermined shape that does not follow the top-edge profile.
7. The system of claim 1 , wherein the lower feed conveyor is configured to convey the lettuce head under the tail-cutting mechanism as the second cutting nozzle is articulated through the tail-cutting arc to produce a v-notch cut in the tail end of the lettuce head.
8. The system of claim 1 , wherein the lower feed conveyor is configured to convey the lettuce head under the tail-cutting mechanism as the second cutting nozzle is articulated through the tail-cutting arc to produce a straight cut in the tail end of the lettuce head.
9. The system of claim 1 , wherein the fixed distance between the lower feed conveyor and the upper feed conveyor is slightly less than the thickness of the lettuce head.
10. The system of claim 1 , wherein the lower feed conveyor has a plurality of conveyor flight pairs, wherein the flight pairs are spaced apart approximately the width of the lettuce head, and wherein the lettuce head is also disposed between one of the plurality of flight pairs.