Mechanism Design And Motion Control Of The End Effector Of Rubber Tapping Robot

Natural rubber is used as a kind of manufacturing raw material for human production,which plays an irreplaceable role in the industrial field,the medical and health field,the military field and daily production.The traditional way of rubber tapping is mainly manual,so the efficiency of rubber tapping is low and the working intensity is heavy.Now the automatic rubber tapping technology can free rubber farmers from heavy manual labor and harsh working environment,which decreases the dependency of rubber tapping industry on rubber farmers’ technical level and increases the economic benefits of rubber tapping industry.The paper studies the mechanism design and motion control of the end effector of rubber tapping robot and combines with the relevant knowledge of mechanical rubber tapping theory and automatic control theory to develop a lightweight,dexterous and self-moving end effector of rubber tapping robot,which not only can achieve the precise positioning requirements of mechanical rubber tapping,but also can complete profiling cutting and passive flexible-guided rubber tapping motion to generate continuous and smooth rubber tapping trajectory,the accuracy in cutting depth was about 0.33 mm and the accuracy in bark consumption was about 0.32 mm.The main research contents are as follows:Firstly,the paper analyzes the relationship between trajectory motion and rubber trunk and secant lines to establish a mathematical model of rubber trunk.Euclidean space rigid body transformation matrix is used to describe the motion process of the secant trajectory.Meanwhile,the relationship between the secant trajectory and the coordinate position transformation of rubber tree trunk is established to guide the profiling mechanism to move according to the secant trajectory.Secondly,ADAMS multi-body dynamics software is adopted to carry out the dynamic simulation of the rubber tapping operation of the profiling mechanism.According to the relationship between displacement,velocity,angular velocity among rigid bodies,equations in Cartesian coordinates is created.And then,Lagrangian equations of motion and corresponding constraint equations for rigid body systems are derived.On this basis,a spring model is established for simulation to accomplish the extraction and analysis of the curves like mechanism cutter displacement,contact force,motion trajectory,etc.Then,ANSYS finite element analysis software is used to carry out static analysis on key parts.The gear transmission system of the end effector and the cutter head group receive the static simulation check through defining materials,dividing the mesh and establishing boundary conditions.The extracted stress and deformation nephogram show that the mechanism design meets the requirements of strength and stiffness,thus having a high safety factor.Finally,an experiment is conducted on the end effector of rubber tapping robot to study the influence mechanism of cutting motion.Accurate helix angle and continuous and smooth helical section can be obtained through helical cutting profiling motion,and then,the features of cutting face and the characteristics of different bark consumption and cutting face shapes are analyzed to further testify the reliability of the end effector.