A time and motion study for evaluation of apple harvest processes with different harvest methods

Authors: ZHANG, ZHAO - North Dakota State University; Lu, Renfu; CANNAYEN, IGATHINATHANE - North Dakota State University

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/27/2020
Publication Date: 12/16/2020
Citation: Zhang, Z., Lu, R., Cannayen, I. 2020. A time and motion study for evaluation of apple harvest processes with different harvest methods. Transactions of the ASABE. 63(6):1957-1967. https://doi.org/10.13031/trans.14144.
DOI: https://doi.org/10.13031/trans.14144

Interpretive Summary: In recent years, self-propelled apple harvest platforms have been increasingly used in the U.S. to address the labor availability and cost issues. However, the existing harvest platforms still have low levels of automation, hence limiting their potential for achieving greater productivity improvement. This study was aimed at evaluating three commercial apple harvest systems and identifying critical technological gaps for further improvement or innovation. During 2018 harvest season, the harvest processes of fruit pickers with the prevailing ladder-and-bucket method and two commercial harvest systems (i.e., DBR vacuum-based and Huron Fruit Systems harvest platform) were video recorded in three commercial orchards in Michigan. A time and motion technique was then used to analyze the time location by pickers for each harvest activity by examining individual frames of the recorded vidoes. The picker’s harvest activities were broken down into the picking and non-picking categories. The picking activities, which are considered essential, were further grouped into the approaching, detaching, and transporting actions. Depending on type of harvest method, the non-picking activities were divided into multiple subcategories. For instance, for the ladder-and-bucket method, the non-picking activities included climbing and descending ladder, moving labber, walking to and away from the fruit unloading station and unloading fruit into the fruit container or bin. Results showed that the average picking time by workers for the ladder-and-bucket, vacuum and Huron harvest methods accounted for 64, 78, and 83% of the total harvesting time, respectively. The detaching action, which is the process that the picker removes a fruit from the limb, only accounted for 30%-32% of the total picking time for the three methods, with the remaining 2/3 time on the approaching and transporting actions. All three harvest methods had low values of the overall efficiency and overall time index (two parameters that were introduced for measuring harvest efficiency) at 21%, 23%, and 26% and 45%, 71%, and 80%, respectively. Hence, there exist significant opportunities for improving harvest efficiency for the three methods. For the ladder-and-bucket method, efforts should be made on improving non-picking activities, i.e., unloading fruit from the bucket to the bin and minimizing the walking distance to the fruit unloading station. For harvest platform systems, efforts should be focused on improving the picking activities through the development of innovative fruit catching or receiving and bin filling technologies.

Technical Abstract: In recent years, harvest platforms have been increasingly used by apple growers in the U.S. and many other countries to replace the traditional ladder-and-bucket harvest method. However, the existing harvest platforms still have low levels of automation, which limits their potential to achieve greater productivity improvement. This study was therefore aimed at analyzing the harvest process by fruit pickers with three distinct harvest methods and determining potential areas for efficiency improvement. Video recordings of workers with the traditional ladder-and-bucket method, DBR vacuum harvester and Huron Fruit Systems harvest platform were collected at three commercial orchards during 2018 harvest season, and they were then analyzed, using the time and motion technique, and categorized into the picking and non-picking activities. Results showed that the average picking time by workers for the ladder-and-bucket, DBR, and Huron harvest methods were 64, 78, and 83% of the total time, respectively. After further breaking the picking activity into the approaching, detaching, and transporting actions, it was found that the detaching action, which is essential in fruit picking, only accounted for 30%-32% of the total picking time for the three methods, with the remaining 2/3 time on the approaching and transporting actions. All three harvest methods had low values of the overall efficiency and overall time index (two parameters that were introduced for measuring harvest efficiency) at 21%, 23%, and 26% and 45%, 71%, and 80%, respectively. Hence, there exist significant opportunities for improving harvest efficiency for the three methods. For the ladder-and-bucket method, efforts should be made on improving non-picking activities, i.e., fruit unloading and minimizing the walking distance to the fruit unloading station or bin. For harvest platform systems, efforts should be devoted to the development of innovative fruit catching or receiving and bin filling technologies to reduce fruit picking time (i.e., reducing the time needed to reach to fruit on trees and transport the picked fruit to conveyors) as well as alleviate the physical demand and occupational hazard for workers by eliminating the use of buckets.