| China is a major apple growing country and apple production has always been a world leader.With the upgrading of the industry in recent years,many orchards have started to adopt dwarf anvil planting methods to improve fruit yield and fruit quality.Pruning is a key operation in apple orchards and has a great impact on the yield and quality of the orchard in the coming year,but the traditional manual pruning or pruning with simple devices has problems such as low operational efficiency,complicated operation and pruning methods not suitable for modern dense apple orchards.To solve the above problems,this paper designs a posture-adjustable apple orchard pruning machine for the pruning requirements of dwarf anvil dense apple orchards with apple tree branches as the operation object,and the main research works are as follows:(1)A modern posture-adjustable apple orchard pruning machine is designed.The machine consists of a frame,a cutter and pruning device,an adjustment device and a control system,which enables the pruning of branches in different planting methods in dense apple orchards.The overall design requirements of the modern orchard pruning machine,the working principle and its main technical parameters are determined according to the planting requirements of the dense apple orchard.(2)Design the key components of the pruning machinery.The circular saw blade is selected as the cutter,and the modal analysis of the circular saw blade is carried out through ANSYS,combined with the analysis of the cutting process of the saw blade to obtain its working speed range;the static analysis and modal analysis of the frame are carried out to verify the rationality of the design;the drive and transmission methods of the horizontal pruning device and the vertical pruning device are determined,the effective sawing length of the pruning device is designed and the selection of the synchronous belt is carried out;based on the The control system of the trimming machine is designed based on the STC32G12K12 microcontroller,which realises the control of the attitude adjustment of the trimming machine and the acquisition and display of the adjustment parameters.(3)Simulation analysis of the process of cutting branches with circular saw blades.A model of a circular saw blade cutting a branch was established,and operations such as simplification,meshing and load application were carried out on the sawing model and postprocessed using LS-DYNA in order to explore the best-fitting sawing parameters.A singlefactor simulation test was designed to determine the levels of the test factors based on the test results: branch diameter 10mm-30 mm,feed speed 3km/h-5 km/h and saw blade speed 2600r/min-3000 r/min.A three-factor,three-level quadratic orthogonal test was designed using the Box-Behnken principle with branch diameter,feed speed and saw blade speed as the test factors and sawing force as the test index.A regression model between the test factors and the test index was established to analyse the influence of each test factor on the test index;the optimum sawing parameters for different branch diameters were obtained after optimisation analysis of the test factors using Design-Expert 8.0.6.(4)Prototype and field test.The feasibility of the design was verified through prototyping and performance debugging;the results of the field test showed that the optimum sawing parameters were: saw blade speed 2800r/min,feed rate 4km/h,when the pruning pass rate was92.8% and the cutting rate was 93.7%,which basically met the pruning requirements of modern orchards. |
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