Design And Test Of Key Components On Picking Machine For Camellia Oleifera Fruit

Camellia oleifera is one of the unique edible woody oil crops in China,mainly distributed in the southern region.As of the end of 2020,the planting area of Camellia oleifera in China has reached 4.451 million hectares,with an industrial output value exceeding 116 billion yuan.However,due to biological factors such as the "synchronization of flowers and fruits",the harvesting of Camellia oleifera fruits has always been dominated by traditional manual operations,which seriously restricts the development of the industry.On the other hand,existing fruit picking equipment causes significant damage to the tree body,and the drop of flower buds during picking can easily reduce production,making it difficult to fully adapt to industrial needs.Based on in-depth research on the mechanism of fruit and flower bud shedding in Camellia oleifera,a new gear comb impact type Camellia oleifera fruit picking device has been developed to address these issues,achieving efficient and low damage picking operations.The main research content and conclusions are as follows:(1)Studied the basic characteristics of related materials such as Camellia oleifera fruit.Taking the site conditions of the Camellia oleifera planting base in Hongshan Town,Hanbin District,Ankang City,Shaanxi Province and the cultivation mode of the Qinba No.1 series of Camellia oleifera as the objects,the biological characteristics and picking mechanical parameters of the fresh fruit of this strain of Camellia oleifera were studied.The size distribution range of Camellia oleifera fruit and flower bud,as well as the critical detachment force,were measured.Furthermore,mechanical performance tests were conducted on materials such as Camellia oleifera,and the range of mechanical performance parameters such as elastic modulus and Poisson’s ratio of the relevant materials was obtained,laying a solid foundation for the subsequent development of harvesting equipment.(2)Determined the overall plan for picking Camellia oleifera fruits,designed the mechanical structure of the key components of the picking device,and selected the models and specifications of the main universal parts.Based on the production status of the Camellia oleifera planting base and the main working modes of forest and fruit harvesting equipment at home and abroad,the overall plan of the tooth comb impact harvesting device has been determined,and the mechanical structure design of key components in the device has been carried out.At the same time,according to the needs of engineering manufacturing of the harvesting device and production requirements such as the site conditions of the planting base,a ZLW-16 small excavator has been selected as the mobile platform for the harvesting device.The results indicate that the overall operation of the device is stable,the tooth comb mechanism operates smoothly,and the impact effect generated by the end effector is significant.(3)Conducted simulation analysis of the impact component on the operation process of Camellia oleifera fruit and Camellia oleifera flower bud.Using the relevant material parameters measured in the early stage,a theoretical picking model of "Camellia oleifera fruit stem fruit branch" was established.The accuracy of the model was verified using basic parameters such as tensile displacement and peak tensile force when the fruit fell off.Furthermore,simulation analysis was conducted on the impact collision effect of the impact component on Camellia oleifera fruit and flower bud,and the maximum critical speed required for the impact component when the Camellia oleifera fruit fell off was determined.It was verified that at this speed,The impact component can effectively avoid damage to the flower buds of Camellia oleifera when picking Camellia oleifera fruits.(4)Completed the prototype trial production of the harvesting device and the performance test of the target base.On the basis of completing the mechanical processing of key components of the picking device and outsourcing of general components,a prototype of the entire device was assembled and the entire picking device was debugged.Through single factor bench tests,the main influencing factors on the yield of Camellia oleifera fruit and the rate of flower bud shedding were determined.At the same time,based on the three factor and three level response surface test,further determine the optimal combination of operating parameters for the entire device.Finally,through on-site picking performance tests at the target base,it was found that when the impact component speed was 455.6r/min,the end effector angle was 1.1 °,and the tooth comb device inclination angle was 23.1 °,the net picking rate of Camellia oleifera fruit could reach 93.13%,while the flower bud shedding rate was only 7.64%.This achieved the design goal of the picking device and provided technical support for the development of the Camellia oleifera picking field.