Design and Experiment of Nondestructive Post-Harvest Device for Tomatoes

Abstract

This paper proposed a whole process tomato harvester with a nondestructive post-harvest collection operation mode, which was aimed to solve the high damage rate problem during the automatic greenhouse tomato harvesting process. The post-harvest device mainly included the net bag mechanism, the conveying and collecting mechanism, whose structure and materials were carefully designed to satisfy the nondestructive collection principle. Numerical simulation was done to evaluate the damage under three working conditions, which showed that the peak contact stress of tomatoes was 0.107 MPa, 0.098 MPa, and 0.11 MPa, respectively, all smaller than the damage stress of tomato peel tissue. In the postharvest prototype experiment, the degree of mechanical damage based on the shelf life of tomatoes during the color turning stage and red ripening stage was used as the evaluation index. Results showed that when tomatoes were dropped from the 60 mm higher position than the net bag mechanism, and the speed of the conveyor belt was 9 r min−1, the degree of mechanical damage at the color turning stage and red ripening stage was 1.9% and 9.5%, respectively. The harvest time of greenhouse tomatoes was always around the color turning stage, thus the proposed device can well meet the agricultural requirements.

Tomato Fruit Quality as Affected by Ergonomic Conditions While Manually Harvested

“…Through numerical simulation, Zu et al [36] presented the internal stress distribution of tomatoes, as well as the structural optimization design of a non-destructive post-harvest device, in which the peak contact stress was 107 kPa, close to the maximum pressures recorded by the Grip System. The Grip System apparatus showed that tomato picking by the picker took between 2 and 2.5 s. Similar results regarding harvesting time and picking forces were obtained by Gao et al [5] in their study of a dynamic measurement system for manual picking of cherry tomatoes.…”