عنوان مقاله [English]
A portable and light pneumatic branch shake system was designed and manufactured in this research for harvesting fruits that can be harvested by shaking branch. Required air flow and electric current are provided for operating system from category containing electrical generator and air compressor on wheelbarrows and portable chassis. Vibration is equipped by programmable logic controller (PLC) for controlling frequency and it is equipped by pantograph system to change amplitude. First farm test was done on olive with three levels of frequency (8, 12 and 16 Hertz) and three times to shaking (5, 10 and 15 seconds) and in constant amplitude of oscillation 5 cm in completely randomized design with four reduplications and second farm test was performed on olive with three levels of frequency (8, 12 and 16 Hertz) and three amplitudes of oscillation (50, 80 and 100 mm) for a fixed period of 5 s in completely randomized design with four reduplication for determining application of branch shake. Some experiments were done for determining static force separating fruit from branch and for comparing it with dynamic force due to performing vibration, as well. The results showed that oscillatory frequency and duration of shaking out have meaningful effect on one percent level on efficiency of shaking system whereas their interaction was not meaningful effect. Comparison of averages showed that increase of the time of vibration didn't have meaningful effect on percent of harvesting olive in constant oscillation but increase of oscillation in constant time of vibration had meaningful effect on percent of harvesting. Also the result of indicator was based on meaningful effect of amplitude of oscillation on falling olive. And by comparing averages, it was given that falling olive is increased with increasing frequency in constant amplitudes of oscillation. Also, it was not observed meaningful differences between percent of falling olive with increasing amplitude of oscillation from 50 mm to 80 mm in constant frequencies. But when amplitude of oscillation increases from 80 mm to 100 mm, the percent of falling olive meaningfully increases. Finally, concerning by performing 16 Hz frequency and 100 mm amplitude of oscillation for 5 s, 90 percents of olive were separated from branches, therefore they were selected as the best amplitude, frequency and time of vibration.