Research On Fruit Mechanical Properties And Picking Mechanical Damage Of Lingwu Long Jujube

LingWu long jujube is unique to NingXia,which get a big presence in NingXia local fruit economic status.It has played a very important role for the economic development of LingWu and increasing the income of farmers.However,the current harvest mode of the LingWu jujube is picked up by ladder.As artificial labor costs increased year by year,it has caused significant negative impact on economic development of the LingWu long jujube fruit,which needs the short-term intensive labor and concentrated picking operations.It also has been the LingWu long jujube the bottleneck of economic development,which very bad for the NingXia LingWu long jujube industry health and the sound sustainable development.Therefore,it is urgent to study the mechanized automatic picking device.In the process of mechanization picking research,due to the LingWu long jujube performance for hard and brittle,its surface will cause the mesoscopic structure changes of fruit loss damage and crack formation under certain mechanical collision and mechanical damage,which could accelerate fruit's rot and have the characteristics of rapid expansion and rot infection.These will seriously affect the shipping period and shelf life of LingWu long jujube,which directly lead to the loss of the economic benefits of the LingWu long jujube.So this article tries to study the mechanical properties of LingWu long jujube firstly,to analysis the macroscopic mechanical behavior of different LingWu long jujube maturity date and the fruit of mesoscopic texture quality,from two aspects of LingWu long jujube for external and internal analysis,in order to establish LingWu long jujube mechanics theory foundation of mechanical harvest.Then the paper explores the two kinds of mechanical damage LingWu long jujubes by use the mechanical equipment when picking and after harvest,to guide parameter design for the actuator at the end of the automatic picking,and take more reasonable and more scientific way of picking.The paper has taken the LingWu long jujube planting in the ShaoWei farming professional cooperatives as the research object.It has carried on the macroscopic mechanical properties of different maturity LingWu long jujube,mesoscopic texture quality,picking and picked two kinds of mechanical damage research.The main research contents are as follows:(1)Study on the macroscopic mechanical properties of jujube fruit.Using fresh harvest of fresh fruit as the material,first,the physical dimension of the sample was calculated.And the variables were controlled within a reasonable range.Using non-metallic mechanics testing machine takes transverse and longitudinal compression experiment with different maturity LingWu long jujube fruit,drawing LingWu long jujube transverse and longitudinal stress strain curve,analyzing LingWu long jujube transverse and longitudinal compression feature.It is concluded that the mechanical properties of different maturity LingWu long jujube indicators,and can divide LingWu long jujube mechanical maturity date interval.It establish the system of LingWu jujube macroscopic mechanical behavior,and lay a theoretical foundation for the subsequent tests.(2)Study on the mesoscopic quality of jujube fruit.With fresh picked LingWu long jujube fruit as material,using the quality and structure instrument to puncture test for LingWu long jujube fruit,to draw LingWu long jujube texture characteristic curve,and take the qualitative analysis of LingWu long jujube's quality.Then according to the test scheme,the paper design the macro-program,further to draw a detailed puncture test curve,to extract the fruit quality index,carrying on the analysis of variance,lastly has established for long LingWu jujube fruit quality evaluation method.It can understand the LingWu long jujube fruit peel and pulp and mechanical properties from internal,also supporting the macroscopic mechanical properties of the LingWu long jujube.(3)Dynamic pressure mechanical damage during picking of LingWu long jujube.With fresh picked LingWu long jujube fruit as material,using the universal mechanical testing machine for LingWu long jujube to design orthogonal extrusion and unloading experiments,and extract the elastic-plastic mechanics parameters of LingWu long jujube from the test results.Firstly,the regression equation between the mechanical damage and the experimental factors was established to explore the influence of various experimental factors on the mechanical damage of LingWu long jujube.Then the regression equation of elastic-plastic mechanical parameters and experimental factors was established to explore the influence of various experimental factors on the elastic-plastic mechanical parameters of LingWu long jujube.Finally,the regression equation of mechanical damage and elastic-plastic mechanics parameters was established to study the linear relationship between jujube and elastic-plastic mechanics.This paper provides a theoretical basis for the parameter design of the end-effector in the automatic picking machine for LingWu long jujube.(4)Percussion mechanical damage after picking of LingWu long jujube.With fresh picked LingWu long jujube fruit as material,using self-made LingWu altitude test rig,two single factor experiment on jujube fruit was carried out to explore LingWu long jujube's mechanical injury of falls and collisions and different maturity LingWu long jujube's fall injury,obtained the main factors that influence the impact mechanical damage for LingWu long jujube.According to the results of single factor experiment,the paper designs the optimization experiment of the response surface,established the regression equation of the impact mechanical damage and the conditions of picking,then take the variance analysis and significance test.Last the paper forecasts the best picking solution design.A set of effective research methods has established,which can study the percussion mechanical damage after picking of LingWu long jujube.The research results of this paper can provide theoretical support and technical foundation for the automatic picking equipment of LingWu long jujube.