| The area of southern JiangXi possess superrior soil quality,special soil provides an excellent environmrnt for planting navel orange.Under the guidance of goveronment and the common effort of people in southern JiangXi,the local industry of navel oranges have been poseessing large scale.However,Navel oranges are mainly harvested by manual operation,it shows low efficiency,and various picking quality,besides,manipulators for harvesting fruits show some shortcoming,on the one hand,most manipulators are made of serial constructures,which causes large cumulative error,intrial shock among joints and heavily posture adjustment;on the other hand,the function of end-effectors of manipulators is single and navel orange is easily damaged in the collecting process finished by end-effector.In order to improve the mechanized operation for harvesting navel pranges and solve some existing problems in manipulators,based on a platform,a robotic arm with decoupled serial-parallel constructure and a end-effector for harvesting navel oranges by simulating the hugging behavior of human and swallowing behavior of rattlesanke,which can benefit to reduce the error and improve the picking quality,the main research contents as follow:(1)Desiginal Scheme and optimal selection of robotic arm and end-effector.According to the goal of picking navel oranges is analysed,appropriate degree of freedom and type of motion pair of robotic arm and accuator are identified,then based on the degree of freedom and motion pair,topological structures needed with decoupled serial-parallel structure are synthesized by using the Orientation and Position(POC)characteristic set and the POC set of selected structure is checked.In addition,three desiginal schemes of end-effector are proposed,the scheme of end-effector to simulate the behavior of hugging and swallowing for harvesting navel orange is selected in papper.(2)Establisment of D-H coordinate syetem and solution of forward and inverse of manipulator.the forward coordinate syetem is choosed to analyze the robotic arm.Because the arm is decoupled serial-parallel structure,forwar-d and inverse calculation of serial structure and parallel structure are finished respectively,especially,the forward calculation of parallel structure is done by adopting the algorithm of improved particle swarm.(3)Parameter optimation and workspace analysis of manipulator.According to the biological characteristics of navel orange tree,the motion magnitude of parameter of manipulator is identified,then workspace of manipulator is analyzed by using the algorithm of Mento Karlo,The ratio of real workspace and theoretical workspace is regarded as the object function,how key parameters affect the workspace is analyzed,the optimal sizes is achieved and results of worksapce between the unoptimized structure and optimized one are given.(4)Determination of mechanical diagram of end-effector,analysis of motion,static forces and size optimization.Motion changes in the process of swallowing of rattlesnake is summarized.The thouguht that simulating the behavior of hugging and swallowing to harvesting navel oranges is introduced in detail,two different diagrams of bionic end-effector are achieved,One of structures of end-effector are analyzed in detail.When navel orange is held and the opening posture is presented by end-effector,the forces appliend on sturcture are analyzed,the kinematic and optimotion design of end-effector are done by using the MATLAB and Adams softwares,and the optimized size are achieved.(5)Establishing model and simulation anasysis of manipulator.Firstly,model of manipulator is built in SolidWorks software,then the main structure is simulated and analysed in Adams software,finally that manipulator can requirement to harvest the navel orange is checked.Moreover based on the the structure of end-effector,the physical model and picking experiment is done,the results show that navel oranges can be harvested by simulating the behavior of hugging and swallowing. |
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