Development of a metering mechanism with serial robotic arm for handling paper pot seedlings in a vegetable transplanter

Abstract

This paper describes the development of an automated metering mechanism for vegetable transplanter. It consisted of a 3- DOF serial robotic arm and an automatic feeding conveyor. The robotic arm was developed to pick and drop tomato seedlings raised in biodegradable paper pots. The volume of each pot was 50 cm3 (3.5 cm diameter and 5.2 cm height) with a maximum total weight of 47 g including pot mix and seedling. A matrix type feeding conveyor was developed to convey the pot seedlings to a predefined position where the robotic arm could pick up these seedlings one by one. LDR (Light Dependent Resistor) - LED (Light Emitting Diode) sensing unit was used to perform the intermittent movement of the conveyor. The developed system was evaluated under both laboratory and field conditions. The robotic arm was able to pick and drop 20 seedlings per minute and its effective cycle time per handling one seedling was varying from 2.5 to 3.1 s. Power consumption of the conveyor of the developed system and the robotic arm was 18 W and 16 W, respectively. The conveying, metering and overall efficiency of the developed metering mechanism under laboratory condition were 96.83%, 95.91% and 92.86%, respectively as compared to 94.7%, 93.28% and 88.33%, under field condition. The developed robotic arm based metering mechanism was simple, light in weight and effectively handled the pot seedlings without damage and would thus help in mechanizing transplanting of vegetable seedlings.