Vibratory Fruit Harvesting: High speed video of apple fruit-stem response to forcing direction and frequency

Abstract

This high-speed video (10x) of an apple fruit-stem subjected to gradually increasing periodic excitation at the upper end of the stem (where attached to the tree branch) provides excellent experimental agreement with the numerically integrated equations of motion for forced oscillation. This double physical pendulum model confirms the predicted nonlinear normal mode behavior for apples being harvested using an inertial shaking device.This video was created as part of a Master of Science Thesis presented to the Graduate School of Cornell University: Parchomchuk, Peter. 1971. Vibratory Fruit Harvesting: An Experimental Investigation of an Apple Fruit-Stem Response to Forced Oscillation. (Note: This thesis provides the context for this video and it will soon be added to this collection.)CONTENTS OF THE VIDEO CLIPS -- A. One-half inch, peak-to-peak displacement Clip 1. Horizontal displacements of one-half inch, peak-to-peak with forcing frequency gradually increasing from 120 to 450 cycles per minute in 22 seconds. Clip 2: Vertical displacements of one-half inch, peak-to-peak with forcing frequency gradually increasing from 150 to 590 cycles per minute in 21 seconds. Clip 3: Circular displacements (simultaneous horizontal and vertical) of one-half inch, peak-to-peak with forcing frequency gradually increasing from 110 to 535 cycles per minute in 27 seconds. Clip 4: Linear displacements at 45 degrees to horizontal (simultaneous horizontal and vertical) of one-half inch, peak-to-peak with forcing frequency gradually increased from 125 to 590 cycles per minutes in 27 seconds.B. One inch, peak-to-peak displacement Clip 5: Horizontal displacements of one inch, peak-to-peak [larger amplitude] with forcing frequency gradually increasing from 100 to 465 cycles per minute in 25 seconds.1_xix1rp7