Development and preliminary evaluation of a new apple harvest assist and in-field sorting machine

Authors: LU, YUZHEN - Mississippi State University; ZHANG, ZHAO - North Dakota State University; Lu, Renfu

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2021
Publication Date: 1/1/2022
Citation: Lu, Y., Zhang, Z., Lu, R. 2022. Development and preliminary evaluation of a new apple harvest assist and in-field sorting machine. Applied Engineering in Agriculture. 38(1):23-35. https://doi.org/10.13031/aea.14522.
DOI: https://doi.org/10.13031/aea.14522

Interpretive Summary: Apples are still manually harvested in the U.S., which contributes to high labor and production costs. Currently, no presorting is performed to remove or segregate low quality or inferior fruit at harvest or in the field. Mixing low-quality apples with fresh market quality apples could incur significant postharvest cost or even economic loss to growers, because of high postharvest storage and packing cost. Hence, technologies that integrate harvest assist and in-field sorting (HAIS) functionalities would be beneficial to the apple industry by enhancing both harvest efficiency and postharvest cost savings. ARS researchers at East Lansing, Michigan recently developed a new apple HAIS prototype machine. This machine has adjustable picking platforms with an ergonomic fruit receiving mechanism covering the entire canopy height of trees, an imaging-based grading and sorting system that is capable of sorting apples for color and size at a speed of up to 12 apples per second, an automatic bin filling system for handling graded fruit in bins, and a computer-controlled hydraulic system for automatic handling of empty and full bins. Inhouse developed operating software is fully integrated with the machine for automatic control of fruit grading and sorting and bin filling and handling. Laboratory tests were conducted to evaluate the fruit sorting and fruit handling systems, and results showed that the two systems had superior performance when they were tested at the sorting speeds between 7.5 and 10.5 fruit per second. Field tests were conducted in a commercial orchard during 2019 harvest season. The machine has met expectations in overall performance and exceeded the industry’s requirement (less than 5%) for harvest-induced apple bruising. With further improvements, the HAIS technology will help U.S. growers achieve economic and labor savings in apple production.

Technical Abstract: Apples are still manually harvested in the U.S. and other countries, which contributes to high labor and production costs. Currently, no presorting is performed at harvest or in the field, which could incur significant postharvest cost or even economic loss to growers, when a high percentage of culls are present in harvested apples. Hence, technologies that integrate harvest assist and in-field sorting (HAIS) functionalities would be greatly beneficial to the apple industry by enhancing both harvest efficiency and postharvest cost savings. A new apple HAIS prototype machine was recently developed, which includes adjustable picking platforms with fruit receiving conveyors covering the entire height of trees, an imaging-based grading and sorting system that is capable of sorting apples for color and size at a speed up to 12 apples per second, an automatic bin filling system for handling graded fruit in bins, and a computer-controlled hydraulic system for automatic handling of empty and full bins. Inhouse developed operating software is fully integrated with the machine for automatic control of fruit grading and sorting and bin filling and handling. Laboratory tests showed superior performance of the machine in fruit grading and sorting, bin filling and handling. Field tests and demonstration conducted in a commercial orchard in 2019 harvest season showed that only 0.4% of harvested fruit were downgraded due to bruising, which exceeded the industry’s requirement for harvest-induced apple bruising. With further improvements, the HAIS machine can be used for commercial harvesting and infield presorting of apples.