| Fruit and vegetable picking has always been a hot issue in the field of agricultural machinery research.In recent years,there are many kinds of picking devices for various fruits,and various innovative institutions emerge in endlessly.However,this traditional manual picking method often can not meet the requirements for the quality and efficiency of litchi picking.In the process of manual picking,there may be the problem of fruit damage,and the efficiency of manual picking is very low.The work of litchi picking is difficult,but it has great economic value.There are few researches on litchi picking in China,who research on litchi picking has low picking efficiency,high fruit damage rate and high requirements for working conditions.Therefore,based on the characteristics of the existing litchi picking mechanism at home and abroad,this paper innovatively designed an adaptive litchi picking device,which has the advantages of wide picking range,strong environmental adaptability,low fruit damage rate,and can easily complete the litchi picking under complex working conditions.The main contents of this paper include:1.The research status of fruit and vegetable picking device at home and abroad is fully introduced,including the picking robot with independent walking function and the mechanical picking device assisted by manpower.The growth environment,morphology and biological characteristics of litchi are analyzed in detail,and the parameters of the picking device are determined according to the biological characteristics of litchi.According to the biological characteristics of litchi and the working principle and parameters of the picking device,the lifting,stretching and executive parts of the picking device are designed to meet the requirements of the specific working environment.The threedimensional modeling of the device is carried out by UG software,including the modeling and assembly of its chassis travel system,lifting mechanism,expansion mechanism,actuator and fruit collection device.2.Through the observation of the movement process of the upper jaw of ants and grasshoppers,and according to the bionic principle of insect movement function,the executive mechanism of litchi picking device is designed by imitating the ant’s mouthpiece.This movement mechanism realizes the integration of clamping and cutting.The movement process is not only the clamping process,but also the cutting process,which realizes the efficient operation behavior.3.The dynamic simulation analysis of the device is carried out by ADAMS simulation software.Through the analysis results,the specific motion path and driving force of each part of the device are obtained.From the simulation results,the maximum driving force and the minimum driving force of the lifting hydraulic cylinder,the driving force of the hydraulic cylinder in the expansion and cutting process are calculated,which are used for the selection and verification of the hydraulic components.The maximum driving torque and rack driving torque of the rotating platform are calculated,which are the static analysis and optimal design of the rear side Provide data basis.4.The key parts of litchi picking device are simulated and analyzed with ANSYS Workbench software,and the displacement strain and stress nephogram are obtained.According to the simulation results,the strength and rigidity of the key parts are checked.In order to optimize the actual picking effect and reduce the stress concentration,the blade and bionic claw are optimized.5.The bionic actuator is processed and trial manufactured.The bionic rake shear actuator is transformed into a physical prototype,and a static strain test platform is built to test the static strength of the prototype to verify its reliability.The correctness and feasibility of the design theory are verified by comparing and analyzing the test results with the finite element analysis results. |
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