Research And Design Of An Apple-picking Robot

With the rapid development of science and technology,China is facing the problem of population aging,and it becomes difficult to obtian the labor.For apple picking,most of China is still accomplished by artificial picking.Therefore,people are looking for a tool to replace labor,so the agricultural picking robot is born.In this paper,apple picking robot is designed and analyzed from four aspects.The main contents are as follows:Firstly,according to the design index of the manipulator,the kinematics model of the manipulator is established,and the workspace of the manipulator is analyzed.The length of each bar is optimized based on the workspace of the manipulator.Secondly,based on the geometric parameters of apple,a underactuated three finger three knuckle end effector is built.The clamping force of apple by the finger was analyzed by Ansys,and the range of clamping force was obtained.The static analysis of the knuckle is carried out under the condition of maximum clamping force.Based on Adams,the kinematic simulation analysis of the end effector is carried out,and the post processing is carried out to get the smooth curves of each parameter,and there is no mutation,that is to meet the requirements of the work.Thirdly,in order to improve the picking rate,we use the shearing mechanism to complete the separation between fruit stalk and fruit tree.The 3D model of the shearing mechanism is established,and the parameters of the driving mechanism are set and calculated.Based on Adams,a virtual prototype model of shearing mechanism is established to analyze its displacement,speed and acceleration in all directions.It can be obtained from the simulation results that the speed and acceleration of the blade in the direction of x,y and z have a sudden change in the 0.15s?0.16s time period,but it is restored to normal in 0.01s,so the effect of the mutation is very small,so the shear mechanism satisfies the work requirement.Finally,the control method is analyzed,and the adaptive PD control method is adopted to establish the control system of the manipulator.the dynamic equation of the three bar manipulator based on Lagrange is established,and its control rate is designed and calculated.Based on Matlab/Simulink and Adams software,a joint simulation system of the manipulator is set up,and the ideal and actual angular displacement curves are compared.The motion of the first joint is relatively stable,which is in good agreement with the ideal curve,indicating the robustness of the control algorithm,the tracking effect and the adaptive ability.Second,the actual angle displacement curves of the three passes have a certain fluctuation and the tracking effect is general.