Development of a Supervised Robotic Prototype for Citrus Harvesting

Abstract

Citrus harvesting has been done manually for the past Sixty-Two (62) years in Eastern Uganda, where commercial citrus cultivation started in the 1960s. Farmers use employees to help in harvesting so that fruits can be picked on schedule. At this point, the hired harvesters gather in gardens and divide up the harvesting tasks among themselves. Some climb citrus trees to reach the ripe citrus fruits on the branches, while others gather fruits on the ground, pack them into sacks, and then transport the sacks of fruits to the required stores. Thereafter, a prototype was developed using a design science approach, and a field-oriented algorithm (FOC) was used to set power and torque during the programming of the actuators for speed regulations. After that, the validation process of the robot was determined by using a stopwatch such that to calculate the time it takes for the developed system to carry out the tasks successfully while in the field and the results showed that it picked up six citruses (6) fruits in five seconds (5 sec) from the ground per two (2) revolutions of the picking mechanism. Compared to hand harvesting, the prototype's storage capacity findings showed that it could only hold forty (40) citrus fruits, which were filled in 33.4 seconds, maximizing harvesting efficiency. And this was achieved by getting 6 citrus fruits collected per two revolutions divided by the 40 which is the maximum storage capacity that was determined after the robot loading for 6 rounds as shown below in the full load capacity = (40/6 = 6.67kgs), then during the study, the time it takes to load to full capacity = 6.67 * 5 = 33.4 seconds. Therefore, this research is highly recommended to citrus farmers in Soroti such that low labor, high quality, and less time are achieved by farmers during harvesting.