ASABE Technical Library - Abstract

Abstract. Vibratory harvesting technology has been widely discussed and intensively investigated in recent years. However, current research mostly focused on the effect of harmonic shaking with fixed joint between actuator and tree which could easily damage the tree body. To explore a more effective vibratory harvesting method, a vibratory harvester driven by gasoline engine with unequal stroke and without clamping the tree was proposed based on pushing and impacting dynamics. The harvester consisted mainly of the shaking mechanism, a steel cable, and the front actuator. The shaking mechanism had a crank-rocker mechanism and a crank-slider mechanism which was used to generate reciprocating motion with unequal stroke. And the steel cable was pulled and released under the running of the shaking mechanism. The front actuator driven by the steel cable had a spring-slider mechanism which was to generate a composite effect of pushing and impacting on branches of fruit tree when the branch was not fastened to the actuator. The kinematics of the shaking mechanism was analyzed and the working stroke equation was derived. A model of the harvester was established and simulated in ADAMS. The kinematics simulation shows that the stroke changed with the angle of the stroke-adjusting crank in the shaking mechanism. By combining ANSYS with ADAMS, a dwarf Chinese hickory tree was modeled as a flexible body and a rigid-flexible coupling model of the harvester and tree was established. The pushing-impacting interaction between the harvester and tree was simulated to obtain the displacement and acceleration of the pushing head in the front actuator and its impacting force upon the branch of the tree. Finally, based on the rigid-flexible coupling model, the influence of different stroke and clamping conditions on the tree dynamics response was analyzed by setting equal stroke or unequal stroke to the machine and by attaching the pushing head to the tree branch or without clamping. The result shows that the pushing-impacting harvester with unequal stroke has an effective excitation on the tree under the same shaking frequency.