The Design Of Pecans Picking Prototype Based On The Vibration

Based on the simple harmonic excitation characteristic, this paper studies the vibration mechanicsmodel of branches of pecan trees, and puts forward the nonlinear mechanical model and the modelparameters.This paper uses nonlinear hypothesis:⑴Put the trunk of pecan tree modeled as elastic cylindrical rod. One end fixed, the quality ball onthe other free end.Quality ball is simplified to be crown quality and the trunk quality of the crown;⑵Put the vibration problem of pecan tree branches modeled as the transverse free vibration ofbeam. One end fixed, the quality ball on the other free end.Quality ball is simplified to be leaves，carpopodium and free end trunk quality.Not considering the axis deformation of the pecan trees, this paper establishes the dynamic modelof the trunk and branches by the simple harmonic excitation. Simulating the bending deformation andvibration properties of trunk and the stems, with test data: top diameter of pecan trees model, diameterat breast height, the length of branches, crown quality, based area, elastic modulus, density and fieldmechanics test and laboratory experiment, we discusse the vibration mechanics equations of the fruittrees branches and obtaine the reasonable conditions for pecans’ falling off (expression by vibrationfrequency). When the vibration frequency is around2.16Hz, we can complete the purpose of pickingpecans. Then based on calculational and experimental data, this paper puts forward the designparameters of the original picking prototype. The picking prototype is drived by gasoline engine. Thencauseing vibration of the picking chuck through the wire soft shaft and the shaft. The steel wire softshaft length is0.89m; the eccentric gear eccentricity is22mm; eccentric quality is66g; picking lengthis5.25m; picking clamping chuck is10-45cm; the maximum working height of the vibration head is8m from the ground. Finally we design the picking prototype based on original parameter. After fieldtesting, when the vibration frequency is between1.91-2.39Hz, the picking is the most effective andpicking rate can reach to84.29%. The average picking efficiency of the prototype is6.37times ofartificial picking.The results show that: the theory model and experimental results fit degree is high; theproposed model can reasonably characterize the dynamic mechanics characteristic of pecan trees.