Vibration dynamics of pruned canopy: Investigating the impact of excitation trajectories on fruit-tree system response

Vibratory harvesting efficiency for forest fruits like Camellia oleifera (edible-oil tree) depends on machine vibration parameters and tree biomechanics, particularly tree structure. This study aimed to improve fruit removal and identify optimal tree structures for mechanised harvesting. A dynamic branch-fruit model based on an epitrochoid trajectory identified excitation frequency and trajectory amplitude as key detachment factors. Box-Behnken experiments determined the optimal vibration response at 7 Hz and 90 mm amplitude, considering branch angle and length. A parallel mechanism-driven canopy shaker was designed for field trials. The C. oleifera morphology was modified by pruning to assess vibration response and attenuation across canopies with varying branch angles. Branches inclined between 30° and 60° exhibited the highest vibration acceleration (26.5 m s⁻²), while those between 0° and 30° showed the lowest (13.8 m s⁻²). Vibration attenuation was the highest in 0°–30° branches and the lowest in 60°–90° branches. Based on these results and conventional practices, an optimal pruning scheme was developed to facilitate harvesting without compromising yield. Field harvesting trials achieved an average fruit removal rate of 75.1 % and an average bud shedding rate of 11.6 %.