Optimum Operating Parameters for a Rotary Drum Shaker for Harvesting Jatropha curcas L.

The objective of this study was to determine the optimum amplitude and frequency of operation for the rotary shaker drum of an experimental canopy shaker used for harvesting Jatropha curcas L. A constrained optimization technique that required the removal of yellow and brown fruits to be as high as possible and the removal of green fruits to be as low as possible was used to determine the optimum operating parameters. The optimum operating condition that retained 90% of the green fruits on the plant was found to be an amplitude of 7.2 cm (2.9 in.) and a frequency of 2.4 Hz. The removal efficiencies for yellow and brown fruits were found to be 75.8% and 80.2%, respectively, for this operating condition. When the objective function of the optimization procedure was changed to limit the amount of green fruits harvested to be no more than 10% of the total fruits harvested to ensure oil quality, the optimum operating parameters were found to be an amplitude of 8.0 cm (3.2 in.) and a frequency of 3.2 Hz for the shaker drum. The removal efficiencies for the yellow and brown fruits for this operating condition were 83% and 89%, respectively. An evaluation of plant damage revealed that no serious damage occurred to Jatropha curcas L. plants when the vibratory shaker drum was operated even under aggressive harvesting conditions that involved an amplitude of 7.6 cm and a frequency of 5.0 Hz.