Development of a laboratory setup simulating cabbage harvesting mechanism and optimization of torque requirement for harvesting cabbage

Aim of study: To develop a new type of cabbage (Brassica oleracea L.) harvesting mechanism in the laboratory that can be used in small-scale cabbage harvester in Indian conditions with minimum power requirement. Area of study: Indian Institute of Technology, Kharagpur, India Material and methods: The mechanism consisted of a cutting unit, a pushing unit and a conveying unit. Two counter-rotating disc cutters were used as cutting devices. Cutting speed, forward speed and cutting position were considered as influential parameters for torque required to carry out the harvesting of cabbage. A full factorial design was followed for the experiment and response surface methodology was used to optimize these parameters for minimizing torque requirement for cutting and pushing the cabbage. Main results Torque decreased when cutting speed increased and when cutting height from the cabbage head decreased. Statistical analysis showed that cutting speed and cutting position affected the total torque significantly. The optimized cutting speed, forward speed and cutting position were found as 590 rpm, 0.25 m s-1 and 0 cm, respectively with a desirability of 0.995. A regression model was developed to predict the total torque for cutting the cabbage stem and it was validated against 10 datasets with a percentage of bias within 10%. Research highlights: The mechanism developed for cabbage harvesting could successfully cut and lift the cabbage heads in the laboratory. These optimized parameters are to be followed in the field prototype cabbage harvester for its successful operation in the field.