Research Of Collision Characteristics Of Mechanical Harvesting Blueberry Based On Fruit Deformation Energy

Blueberry is a kind of healthy food.With the increasing of demand for blueberry fruit,the planting of blueberry trees increased year by year.Mechanical harvesting has been the main way of blueberry harvest.And the scientific method of mechanical harvest and the degree reduction of fruit injury have been the difficult problems to be solved.Aiming at the problems,through the theoretical analysis,numerical simulation and physical experiment,the characteristic of collision injury of the blueberries is researched.The evaluation standard of mechanical injury is established.The influence factor on fruit deformation energy is obtained.The theoretical basis and data reference are provided for improved design of the blueberry harvester by the research results.The characteristic of fruit collision is researched.Firstly,quasi-static compression test for the fruit is executed.It is proposed that the deformation energy can be used to evaluate the fruit injury.And the mechanical parameters of the fruit is obtained.The evaluation standard of fruit injury is established.The process of fruit falling and collision during mechanical harvesting is researched based on the energy balance.The main influence factors on deformation energy is analyzed.The collision deformation process is analyzed based on Hertz Theory.The equation of fruit deformation is established.The numerical simulation and experiment verification are executed for the collision characteristics.The fruit collision scheme is designed.The finite element model of the collision between a fruit and a collecting card is established,which is used for analysis the max the maximum stress and maximum strain of the fruit deformation zone.It is used to solve the equation of fruit deformation and calculate the theoretical value of fruit deformation energy,and determine the parameter values of the influence factors that minimize the deformation energy.The high-speed photography test is to record parameter values of collision in the process of the fruit falling.The energy loss equation is established to solve the test values of fruit deformation energy.The test values and theoretical values of fruit deformation energy are compared to obtain the order and significance of the influence factors of the fruit deformation energy.The optimal working parameters of the harvester are filtered.The discrete element method is used to simulate the process of mechanical harvesting and determine the feasibility of the optimal working parameters of the harvester.The equivalent model of the blueberry fruit,the harvester and the tree are established,of which the parameters are provided.The distribution of the particle quantity of the he variation of kinetic energy conversion and the total energy is analyzed.The injury degree of the fruit is determined,which is the basis for operating parameters of the actual mechanical harvesting.The blueberry collision characteristics of mechanical harvest is researched.It is provided that the deformation energy of the fruit is used for injury evaluation.The optimal working parameters of the harvester are obtained,which is the scientific reference for the use of the harvester.The paper has important theoretical significance and application value.