Design And Simulation Study Of A Tomato Collateral Pruning Robot

As one of the world's three main tomato growing area,China has a planting acreage of over 100 million Ha.The annual yield of tomatoes is large and presents a continuous growth trend.While the growth ability of tomato plants' lateral is strong enough to be a great threatening of tomato yield and quality.Till now,the pruning work of tomato collaterals that costs large amount of labor is stll basically done by manual completion and could cause a high labor cost.Thus,an 8-DOF tomato collateral pruning robot with climbing ability and flexible action is designed and kinematics and dynamics simulation research and analysis of the robot are carried out.The development of the robot can reduce the labor costs by replacing man kind and can increase tomato fruit's quality and yield by improving pruning efficiency and quality.The main contents of this paper are as follows:(1)The scheme of the robot's overall structure is determined by studying the tomato planting environment and the collateral growth charateristics and dimension parameters' optimization of the pruning manipulator is carried outthrough MATLAB.(2)Mechanical structure design of the tomato collateral pruning robot including a 6-DOF joint manipulator and a laser cautery type end-effector and a2-DOF mobile platform is completed by building and assembling the virtual models of in Solidworks.(3)The kinematic model of pruning manipulator based on D-H representation is established and its positive solution and the inverse solution of kinematic equations are deduced.The 3-D model of the manipulator is imported into ADAMS and kinematics simulation upon this model is executed.The correctness of the positive and inverse kinematics equations are verified through comparing the deviation of manipulator's end location and attitude between theoretical calculation and actual simulation results.The verification provides the guarantee for the reliability of the dynamics simulation and the rigid flexible coupling dynamics simulation.(4)Dynamics simulations under target accessibility and obstacle condition in Cartesian space were performed in the target space,and the curve of angular velocity and angular acceleration for each joint under these two typical operating conditions was obtained.Taking no significant impact upon the motion process as the goal,driving function optimization of the manipulator's avoidance dynamics simulation along the multi-segment path was performed so that the manipulator could acquire an effectively impact reducing during it completes obstacle spanning action.Finally,the selection of the joint motors wasperformed according to the simulation results of the two typical operating conditions.(5)The forearm and upper arm's Solidworks models are imported into ANSYS to generate the corresponding modal neutral files,then the MNFs are used to replace the corresponding rigid parts of the original manipulator model to generate rigid-flexible coupling model.Dynamic simulation of the coupling model is carried out for two purposes.Firstly,analyzing the causes of deviations by comparing the location and attitude error of the end effector and comparing joint angular acceleration changes under rigid-flexible coupling.Secondly,analyzing the dynamic strain and stress amplitudes in the target space and verifying the selection of the robot materials.