| Ratoon rice is a special mode of rice cultivation by using residual rice stalks and roots to sprout spikes again,which can maintain high yield and excellent quality characteristics under different moisture and soil conditions,and is increasingly popular among agricultural producers.However,the traditional regenerative rice harvester was developed from the perspective of reducing crushing,limiting the storage volume of the grain bin in order to reduce the grounding ratio pressure,resulting in the first season of the machine harvesting link equipment need to go back and forth several times to unload grain,causing a lot of unnecessary crushing traces on the field,reducing the yield of the regeneration season.Therefore,this study proposes a scientifically sound path planning method for the firstseason harvest of ratoon rice to enhance its overall economic benefits.This method addresses the agricultural requirement of minimal compression marks and light compression during harvesting and unloading,and is based on an analysis of domestic and international path planning research.This article proposes a quadrilateral field design that considers the grain unloading process for the first-season harvest of ratoon rice.The main research content and conclusions are presented below.(1)Detailed analysis of the path requirements for the first-season harvest of ratoon rice and the traditional harvesting path.From the perspective of improving overall economic efficiency,the first-season harvest of ratoon rice should meet the agronomic requirements of less and light pressure.An ideal harvesting path should ensure the integrity of the operation process,complete coverage of the operation range,and meet many other requirements.This paper takes the traditional harvesting paths of rotary type and ox-plough reciprocating type as the analysis objects,and conducts a detailed analysis of the turning methods and different grain discharge conditions in the two types of harvesting path planning.We established a calculation model for multiple indicators,such as the length of the machine’s driving path and the area of pressure,to provide reference for proposing new path planning methods for the first-season harvest of ratoon rice.(2)Establishment of a path planning model that considers the grain bin capacity limitation of the harvesting machine.A path planning method for the first-season machine harvesting of ratoon rice applicable to quadrangular fields was established by considering the characteristics of multiple unloading during the operation and referring to the capacity-limited arc path problem in the logistics and distribution field.Firstly,an operation information model was established based on the field conditions and machinery parameters,and the operation path of the turning area at the field boundary was flexibly determined according to the machine’s maximum single operation distance and the limitation of the grain bin volume.Then,the unharvested area was divided into multiple operation rows according to the harvesting width of the combine harvester,and the optimal direction of the operation line with the minimum number of turns and the minimum increase in compaction area during the turning process was determined.Finally,a path planning model was established for scheduling the operation machinery in multiple operation rows to complete all operation goals.The path planning scheme was improved to consider the actual situations of crop lodging and multiple unloading points during the actual harvesting operation.(3)Determination of path planning model solving algorithm considering grain bin volume limitation and its improvement.Based on the established path planning model for the first-season harvesting of ratoon rice,the efficiency and results of various intelligent solving algorithms were compared under different dataset sizes,and ultimately,genetic algorithm was chosen as the target solving algorithm.Several solving stages of genetic algorithm were correspondingly improved,including the encoding scheme during algorithm solving,optimization selection strategy,and cross-mutation.Then,the performance of the improved algorithm was tested with the same dataset size,and the test results showed that the iteration speed and data results of the improved algorithm were better than before,which could meet the solving requirements of the problem of path planning for the harvesting of ratoon rice.(4)Theoretical testing and field simulation experiments of the path planning scheme.The comparison of different path planning methods under the same conditions was carried out with the crushed area and the length of the driving path generated in the whole process of operation as the main evaluation index,and the results show that the planning method proposed in this paper reduces about 11.21% ～ 28.03% in the crushed area and about 6.81% ～ 23.46% in the path length than the two traditional harvesting paths;Several factors affecting the effectiveness of the first-season harvesting of ratoon rice were experimentally investigated,including different parameters of harvesting equipment,different numbers and distributions of unloading points.Comparative tests were conducted on the operational effectiveness of existing ratoon rice harvesters in the same field.The results showed that the dual-channel ratoon rice harvester developed by Huazhong Agricultural University had the best operational effectiveness,with an overall harvesting compaction rate of less than 30%.Field simulation experiments were conducted using a tracked walking chassis under different operational path planning methods.The results showed that the proposed path planning method for first-season harvesting of ratoon rice in quadrangular fields,which takes into account the volume limitations of the machine’s grain bin,has significant optimization effects.(5)Design of software for path planning of ratoon rice harvesting in the first-season.Using the Python programming language and multiple development tools and plugins,a path planning software for the harvesting of regenerative rice was designed.The software can perform optimal driving path planning based on specific field and harvesting equipment parameters to achieve the best harvesting results.The software database also includes parameters of various mainstream harvesting machines on the market,making it easy to test and compare the quality of different harvesting machines in the same field.The testing results of the planning software’s harvesting quality can also be used to guide the parameter design of dedicated regenerative rice harvesting machines,providing certain assistance for the development of harvesting machinery. |
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