Motion trajectory of different fruiting types of Camellia oleifera fruit under vibration: Theoretical and experimental studies

Camellia oleifera , an important oil crop in China and worldwide, is widely used in washing, food, medical, industrial products, and the harvest of Camellia oleifera fruit necessitates efficient collection operations. The vibration shedding mode of the fruit under different factors is an important basis for the development of intelligent fruit harvesting equipment. In this study, we established a Camellia oleifera branch-stalk-fruit vibration system dynamics model, built a branch vibration platform, and used a high-speed camera system to study the fruit movement trajectory under different branch lengths, hanging fruit modes, and vibration parameters. The motion trajectory of a hanging fruit with a branch length less than or equal to 10 cm exhibited a Lissajous trajectory. This trajectory was a superposition of two simple harmonic motions at frequencies above 4 Hz in the vertical direction. For a hanging fruit with a branch length exceeding 10 cm, the motion trajectory exhibited an arc swing analogous to that of a nonlinear pendulum. This trajectory gave rise to the jumping and mutation motions of a nonlinear pendulum at frequencies exceeding 4 Hz. The movement range and swing amplitude of the fruit hanging from the middle of the branch were larger than those of the fruit hanging from the end of the branch. Furthermore, the frequency required for the fruit to fall was lower than that required to excite the fruit hanging from the end of the branch. A vibration harvesting method for hanging Camellia oleifera fruit was analysed, and a vibration scheme and theoretical basis were provided to improve harvesting efficiency. • Dynamic vibration models of Camellia Oleifera fruit-stalk-branch under varying fruiting conditions were built and analysed. • Using a high-speed camera system to track and reconstruct the actual movement trajectories of Camellia Oleifera fruits. • Proposed two degrees of freedom motion of fruit based on Lissajous pictures. • Theoretical and experimental validation analyses have led to recommendations for vibration harvesting of fruit.