Design And Simulation Analysis Of Hand-held Berry Harvester

At present,the harvest of berries in our country is mainly artificial,with low efficiency,high labor intensity,and high operating costs.Berry harvesting techniques have lagged behind the needs of the development of berry crops,restricting the development of berry industry.Therefore,it has great significance to study the mechanical harvesting technology of berries.In order to improve the recovery efficiency of berries,reduce fruit damage,this paper was based on the measurement of the geometry and mechanical properties of berry fruit trees.The dynamics model of berry branch was established,simulation analysis of vibration harvesting was carried out,a hand-held vibration harvester and its collecting device were designed,and the test was carried out.In order to provide the basic parameters for establishing mechanical model of berry fruit,according to the Heilongjiang Province in the field under the condition of indigo fruit tree branches and branches length,mass,diameter,lateral branch growth angle,measurement of geometric and physical parameters such as the basic position of height growth,the variation of the main geometric features of the fruit of indigo was analyzed.Bending tests were performed on the branches,branch bending stiffness test,elastic modulus and mechanical properties and their variations.The three year old indigo fruit trees,the fruit top and diameter both showed a linear positive correlation between them,between the main square and two strong diameter quality related,which was the two linear relations.The average value of the height difference of lateral branch growth point was 49.24 mm.The average value of lateral growth angle was 27.930.The main distribution range was(10,40],accounting for 94%of the total statistics.There was a strong correlation between the lateral mass and diameter,which was the two linear relationship.The initial diameter range of lateral growth point was 1.2-2.7 mm.The initial diameter and length decreased with the increase of the height of the lateral branch.The stiffness of the branch was proportional to the fourth square of the diameter.In order to provide the basis for the design of berry vibration harvester,according to the external morphology and growth characteristics of fruit trees,the geometric model of fruit trees was established which was based on the test of mechanical properties of fruit trees.The establishment of berry branch dynamic model with using the finite element method,model analysis was carried out.The displacement of each point on the response of the branch sinusoidal force excitation was analyzed.When the middle position of branch was excitated,the displacement of fruit trees in the upper part of the branch point displacement was greater than the lower end position of the vibration,but the displacement of branch root was slightly less than the displacement of the lower position of the vibration.The results showed that the intermediate position excitation was better than the lower position excitation.A hand-held berry vibration harvester was designed,dynamic model was established for harvester-recovery.The influence of the vibration pattern and the parameters on the movement of the tree and its force was analyzed by using the field test technology of high speed camera.The numerical simulation experiment was carried out,the vibration form of stable vibration,compared with sine function at the same speed,correlation coefficient was greater than 0.95.The dominant frequency of vibration response remained the same as the exciting frequency,and more than one frequency of intermittent vibration,three times of the main frequency.The vibration displacement amplitude is much smaller than the vibration displacement and acceleration of the tree branch.Speed,eccentricity and amplitude which had influenced on the branches’ force was significant,and amplitude was remarkable.When the speed of 926 rpm,eccentricity of 15 mm,recovery of finger spacing of 7 mm,branch force was 72 N,the displacement was 18mm,which was the best harvest,and the branch damage was at least.Using the high-speed camera technology to verify the branch displacement,the simulation results were correct.When the recovery efficiency was 60.6 m2/h and the recovery was 92.4%,the vibration of branch without damage and recovery met the production needs.A berry collection device was designed,the state of the frame and the working state of the collecting table were analyzed.The rack had simple structure and could meet the requirements of strength and rigidity.The platform adopts four bar mechanism,in the collection,walk two kinds of work condition,collection platform and ground tilt angle changed as 5.30.It was convenient to collect berries,and used the change of the center of gravity of the acquisition platform to ensure the working position.The results of this study could provide basic data and reference value for the development of mechanical vibration and the field operation of berry.