Optimization Study On Operation Parameters Of Cassava Shovel

In China,the dominated method for cassava harvesting is manual uplifting.As a comparison,digging and pulling cassava harvesters have the advantages of good adaptability,low power consumption,and high harvesting efficiency,which are the main research direction of cassava harvesters.Digging and pulling cassava harvesters can pull up cassava directly in moderately hard soil.However,without loosening the soil first,digging and pulling cassava harvesters can easily break the roots in harder soil.Therefore,the quality of the shovel has a great impact on the harvest of cassava.The existing shovels have mainly considered the influence of structural parameters while some other important operation parameters such as the tillage depth,and the horizontal distance between the shovel and the root have been underestimated.So,it is of great significance to optimize the shovel by considering these operation parameters.In this thesis,I designed a double-wing shovel for cassava harvesting in the red clay soil at Guangxi: SPH and FEM coupling were used to establish a shovel-soil-cassava systematic dynamics simulation model,and the accuracy of this model was verified through field experiments;by using this model,the operation mechanism of the shovel was analyzed,and the force change at different positions of the shovel wing and heights of the shovel handle was obtained;the simulation experiments were performed based on this model and the second regression experimental design method,then mathematical models between operation parameters and traction resistance,soil loosening degree,and maximum root stress were established;as a result,the operation parameters and the structure of the shovel were optimized and improved using genetic algorithm.The results have shown that,within the right range of operation parameters,the cassava roots did not break.When the tillage depth and the horizontal distance between the shovel and roots were 25 cm and 35 cm,respectively,the traction resistance was 4609.52 N,the soil loosening degree was 7.5 mm and the maximum stress on roots is 1.822 MPa,indicating a good soil loosening effect.With a harder soil,the operation parameters of the shovel should be adjusted appropriately to ensure a better degree of soil loosening and less traction resistance without damaging cassava.