Research On Dynamic Properties Transmitted Of Forest-fruit Vibratory Harvester System

Harvesting operation plays an important role in the forest-fruit production. A comprehensiveunderstanding of dynamic properties transmitted of forest-fruit vibratory harvester system istherefore important for designing efficient mechanical harvest system and improving harvestefficient. In this paper, dynamic model of tree-fruit vibratory system was established anddynamic properties test system of tree vibratory was designed. Based on these, dynamicproperties transmitted of forest-fruit vibratory harvester system indoor and outdoor experimentswere studied on this test system.Dynamic model of tree-fruit free vibratory system and forced vibratory system wereconstructed with the simplified model method. The expression of vibration function and thedynamic response of tree-fruit free vibration system and forced vibratory system were derived.The results showed that tree-fruit vibration form was determined by exciting force and tree-fruitphysical properties (density, height, diametre).The primary goal of indoor experiment was to study the different direction (X, Y, Z)dynamic responses to all monitor locations of tree-fruit and the distribution of applied vibratoryenergy to tree-fruit under different frequencies. The experiment results indicated that branchacceleration responses of X, Y, Z direction and excitation point displacement responses of X, Ydirection became larger as the frequencies were increased. With monitoring points were locatedfurther from the excitation point, acceleration responses of X, Y direction became smaller, butacceleration responses of Z direction became larger. The relative kinetic energy ratio (RKER) ofX, Y direction on different vibratory transmission paths increased first and then decreased alongeach vibratory tran paths, but RKER of Z direction became larger.Based on indoor experiment, outdoor experiment was studied. The experiment resultsindicated that branch acceleration responses of X, Y, Z direction and excitation pointdisplacement responses of X, Y direction became larger as the frequencies were increased. Withmonitoring points were located further from the excitation point, acceleration responses of X, Ydirection became smaller, but acceleration responses of Z direction became larger. Vibratoryenergy transmitted along the same branch, REKRs at almost all monitoring positions of X, Ydirection varies slightly, the maximum REKRs were generated near branching node, butREKRs of Z direction along the each path became larger. Vibratory energy transmitted fromleader limb to branch-on-leader, vibratory energy of X, Y direction decreased, vibratory energyof Z direction was distinctly amplified. Compared indoor experiment result with outdoor experiment results, the change trande of dynamic responses along specimen was similarbetween indoor experiment and outdoor experiment. The exciting frequency and monitor pointshad significant effect on dynamic responses.Based on reaserch of dynamic properties transmitted of tree-fruit vibratory system, futherthe fruit detachmet experiment was studied. Fruit vibration form under exciting force and theprimary resonant frequencies were obtained. The experiment results indicated that fruitdetachment force was determined by transmition of vibration energy, fruit physical propertiesand tree-fruit physical properties. The optimal frequency range was15Hz-20Hz. The vibrationmovement of fruit was along Z direction.