Desitzn And Analysis On Vibratory Harvestiniz Mechanism For Fruit Based On Epitrochoid

Due to the adjustment of agricultural industrial structure and the increasing consumptiondemand of fruit in China, the fruit tree planting area and yield of China had ranked first in theworld in recent years. However, harvesting as the most important part of fruit industry hasbecome a bottleneck in the development of fruit industry due to the shortage of mechanicalequipments for fruit harvesting which request high efficiency and low damage.To find out appropriate excitation pattern on fruit tree and design a novel vibratory fruitharvesting mechanism, the influence of different kinds of displacement patterns on vibratoryfruit harvesting was simulated based on finite element software (ANSYS). According to thesimulation results, a novel vibratory fruit harvesting mechanism was designed. Then, thekinematics and dynamics of this mechanism were analyzed and main parameters were optimized.Finally, a prototype of this mechanism was built to validate the theoretical analysis andsimulation results. The main contents and achievements are as follows:1. A hypothesis about ideal fruit tree excitation pattern was put forward based on the pastresearches, which included the following contents:1) Most branches in a tree could bestimulated effectively;2) Vibratory energy was well distributed;3) Vibratory intensity wassufficient. In order to verify this hypothesis, a China hickory tree model was established in finiteelement software (ANSYS) to implement transient response analysis. Linear, circular andepitrochoid displacement patterns with same amplitude of94.6mm and frequency of3Hz wereimposed on the fruit tree model to observe the distribution of the maximum resultant accelerationin the tree. Statistical results showed that mean value and standard deviation of the accelerationscaused by these displacement patterns were45.97,37.71,64.04m/s2and39.03,24.18,28.10m/s2,respectively. Furthermore, hypotrochoid and epitrochoid displacement patterns with cycloidcount of3and5were compared by the same method. Mean value and standard deviation of theaccelerations were92.00,106.83m/s2on the condition of3cycloid counts and55.12,50.56m/s2on the condition of5cycloid counts.2. According to the simulation results of fruit tree dynamics, a novel vibratory harvestingmechanism for fruit tree with adjustable output acceleration range was designed based onepitrochoid. The epitrochoid mechanism as the core component of harvesting mechanism was mainly composed by two external planetary gear trains with tooth number ratio of3:1and5:1,which could be shifted by gear rack mechanism. Then, the kinematics and dynamics model ofthe epitrochoid mechanism were analyzed.3. Main parameters of the epitrochoid mechanism were optimized by parameter-guidedoptimization algorithm. An optimization program was developed based on the proposedalgorithm and the result was: R=35mm, ra=14.4mm, f=3Hz. According to the optimizationresults, three-dimensional model of vibratory harvesting mechanism for fruit tree was built andthe torque of the epitrochoid mechanism was calculated by using ADAMS which was2.9Nm.4. A prototype of vibratory harvesting mechanism for fruit tree was manufactured and itstrajectory was recorded by Phantom v5.1high-speed photographing system. Trajectories ofexperiment, theoretical analysis and virtual simulation were consistent, which verified the designof this harvesting mechanism. A dynamic response test of fruit tree was carried out in lab. Theaccelerations of test points on fruit tree were measured by AVANT MI-7008data acquisition andanalysis system when the prototype excited the fruit tree. Statistics results indicated that themean value and standard deviation was57.13m/s2and33.01m/s2, which confirmed that theepitrochoid mechanism could stimulated the fruit tree effectively.