| China is a big country of citrus production.China ranked first in citrus production accounting for 29% and cultivation area accounting for 27% of the world in 2016.Shoots grows are the main method of new and old replacement and the tree grows,three times shoots growths will occur each year.The shoots growths have the characteristics of long period of growth,large amount of growth and irregular growth.And the shoots of different periods have different characteristics,so that the management methods of shoots in different periods are different,which has bring great inconvenience to the handling of orchard management.Removing shoots is to solve the problems of shoots growths compete for young fruit to affect production and disease and insect pests caused by the shoots growths influence the health of the tree.However,citrus shoots removing work is still done by hands currently,which leading to low operating efficiency,great labor intensity of farmers and high production cost.Therefore,the method of artificial removing shoots can not satisfy the large-scale production of citrus.In order to realize the mechanization of citrus shoots removing,it has practical significance to develop citrus shoots removing machine.The main research contents are as follows:(1)Research on this material for citrus shoots,exploring the mechanical and botanical characteristics of citrus shoots,established a geometric model of citrus shoots about minimal leaf and shoots angel is 27.7°,minimal double leaf angel is 41.9°,and proposed the machine's job requirements,in order to guide the design of citrus shoots removing machine;make sure the cutting method is unsupported cutting,the cutting process is cantilever beam model,the main factors affecting the success rate of cutting,initially determine the cutting line speed as 35m/s.(2)According to the overall design plan,the structure design of the whole machine has been completed,including cutting components,telescopic bar assemblies and power control transmission components.It is determined that the cutting blade is a circular saw blade and a rotary blade.The diameter of the blade is 44 mm,the cutting motor is XXD KV2200 aircraft model brushless motor,the telescopic rod is a carbon fiber telescopic rod,and the energy supply battery is 12 V lithium battery.(3)A special test rig for the test of citrus shoots removal was designed,and the principle and method of bench test were introduced.The effect of the diameter of the shoots on the cutting was tested,the results show that the cutting power increased with the increase of the diameter of the citrus shoots,and showed a significant positive correlation of two times polynomial.(4)The static analysis and modal analysis of the circular saw blade of the core part of the machine are carried out,the total deformation,stress and strain value are obtained,the rationality of material selection and dimensional structure is verified;Through modal analysis,the natural frequency of the circular saw blade is obtained,and no resonance phenomenon is observed in the work.(5)The performance test of the citrus shoots removing machine is carried out.The cutting success rate of the circular blade is 93.8%,the ideal rate of stubble length is 88.4%,the cutting success of the rotary blade is 100% and the ideal rate of stubble length is 61.9%.It is concluded that the circular blade is suitable for the removal of small and separate shoots,the rotary blade is suitable for the removal of large and dense shoots. |
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