| In view of the serious phenomenon of Cerasus humilis branches lodging and laborious time of manual collection,it restricts the large-scale development of Cerasus humilis industry.In this paper,based on the experience of domestic and foreign scholars in the research of small forest fruit harvesting,combined with the agricultural requirements and growth characteristics of calcium fruit planting,design and experimental research of Cerasus humilis harvester are carried out by the method of theoretical analysis and experimental method,and a self-propelled electric Cerasus humilis harvester with high yield,low damage rate and reliable performance is developed.The main conclusions of this paper are as follows:(1)The agronomic requirements of Cerasus humilis planting were investigated.The plant spacing of Cerasus humilis planting was 0.5 m,narrow row spacing was 0.5 m,wide row spacing was 1.2 m.The basic physical characteristics of Cerasus humilis related to harvest were measured,including the growth characteristics of branches at the mature stage of Cerasus humilis,the morphological parameters of lodging branches and the physical parameters of Cerasus humilis;Through the static compression test of Cerasus humilis,based on the deformation energy,the damage evaluation basis of Cerasus humilis were established: the deformation energy was 0~28.56 m J for mild damage,28.56~88.21 m J for moderate damage,88.21~123.41 m J for severe damage,and more than 123.41 m J for Cerasus humilis fracture.According to the dynamic drop impact test of Cerasus humilis,the equivalent drop critical height of Cerasus humilis is 2.97 m,and the impact velocity is 7.63m/s.(2)The whole structure of Cerasus humilis harvester and the design and analysis of five key components(holding device,carding device,screw conveyor,walking chassis and control system)were carried out.The working principle of the whole machine is as follows:the gripping device guides the branches of the Cerasus humilis to be harvested to the direction of the fruit removing device and straightens them during the guidance process.The fruit removing device combs the Cerasus humilis through the rotation of the comb teeth,and the conveying and collecting device transmits the Cerasus humilis to the car compartment by the way of spiral conveying;The design of the device: according to the lodging characteristics of the Cerasus humilis branches,the test-bed was designed to analyze the stress of the Cerasus humilis branches,the moving track theory and ADAMS simulation analysis,and the experimental research was carried out.Finally,the optimal structure parameters and working parameters of the device were determined as: elevation angle 50°,speed ratio 4,and the distance between fingers 160 mm;Design of carding device: through the analysis of the structure and working principle of carding device,it is reasonable to determine 3 rows of comb teeth in carding device,and the comb spacing is 20 mm.Based on the analysis of the force and movement track of the Cerasus humilis in the process of carding,the width of the fruit receiving chamber was determined to be 335 mm,and the distance between the Cerasus humilis and the side wall of the fruit receiving chamber at the initial state was 250~560 mm;Design of screw conveyor: the force and movement of Cerasus humilis in the process of screw conveyor are analyzed.According to the characteristics of conveyor,the outer diameter of screw conveyor blade is 120 mm,the inner diameter is 32 mm,the lead is 100 mm,the outer diameter of conveyor pipe is 140 mm and the inner diameter is 130 mm;The design of the walking chassis: the static analysis of the walking frame is carried out by using ANSYS software,and the maximum stress is83.59 MPa,which is less than the allowable stress 117.5 MPa,which meets the strength design requirements;the minimum turning half diameter is 3807 mm according to the steering performance analysis;Based on the analysis and calculation,the drive motor is a BLDCM with rated voltage of 60 V,rated power of 3000 W and rated speed of 2000 r/min;The design of control system: the design of walking control system,harvesting control system,hydraulic lifting system.(3)In the field experiment,the forward speed of harvester,the rotation speed of lifting motor,the rotation speed of removing motor and the rotation speed of the conveying motor were taken as the experimental factors,and the harvest rate and the damage rate were taken as the experimental indexes.The test results show that the main and secondary order of the impact on the harvest rate is: forward speed of harvester > rotation speed of lifting motor >rotation speed of removing motor > rotation speed of conveying motor.The main and secondary order of the impact on the damage rate is: rotation speed of removing motor >rotation speed of lifting motor > rotation speed of conveying motor > forward speed of harvester.The optimal combination of working parameters is as follows: forward speed is0.2 m/s,rotation speed of lifting motor is 104.6 r/min,rotation speed of removing motor is22 r/min,rotation speed of conveying motor is 137.4 r/min.under the combination,the predicted results are as follows: the harvest rate is 81.26%,the damage rate is 2.80%.The results of validation tests were 82.12% and 2.79% respectively,and the relative error between the predicted value and regression model was not more than 3.45%.The self-propelled electric Cerasus humilis harvester designed in this paper can provide a reference for the research and development of Cerasus humilis harvesting machinery and the industrialization of Cerasus humilis. |
