AE—Automation and Emerging Technologies: Development of a Three-Degrees-of-Freedom Robot for harvesting Lettuce using Machine Vision and Fuzzy logic Control

In Korea, research projects on year-round leaf vegetable production systems are in progress, most of them focused on environmental control. Therefore, automation technologies for harvesting, transporting and grading are in great demand. A robot system was developed for harvesting lettuce plants, comprising of a three degrees of freedom manipulator, an end-effector, a lettuce-feeding conveyor, an air blower, a machine vision device, six photoelectric sensors and a fuzzy logic controller. Fuzzy logic control was applied to determine appropriate grip force on lettuce plant. Leaf area index and height were used as input variables and voltage as an output variable for the fuzzy logic controller. The success rate of lettuce harvesting was 94·12%, and the average harvesting time was approximately 5 s per lettuce plant.