Design And Experiment Of Wing Surface Skinning Robot Engraving System Based On Electromagnetic Variable Stiffness Joint

Large-scale thin-walled components such as machine skins and aircraft siding are required to be subjected to the engraving operation.Engraving operation is the operation of removing the outer protective rubber.The engraving operation requires that the surface protective layer is infiltrated without destroying the underlying skin metal;at present,the engraving operation is manually completed in the production process,and the precision of the manual engraving mainly depends on the personal experience of the worker,and the high precision and high efficiency cannot be guaranteed engraved.In this paper,based on the electromagnetic variable stiffness joint design,the robotic engraving system of the wing surface skin is realized by the electromagnetic variable stiffness joint in the system to achieve precise force control,and the precise position control is realized by the industrial robot.At the same time,a multi-lattice flexible fixture for thin-walled parts was designed;the engraving experiment was completed.The paper mainly studies in the following aspects:1)Firstly,the kinematics modeling is carried out for the FANUC R2000 robot.The inverse kinematics theory of the robot is used to solve the angle of each joint in the trajectory motion.The motion simulation analysis is performed by Matlab,and the movement angle of each joint during the movement process is calculated.The kinetic model uses the kinetic model to calculate the relationship between the end-engraving force and the engraved angle and verify the simulation by Matlab.2)For thin-walled large-surface curved skin parts,design and process multi-lattice flexible tooling and model the tooling system.Flexible tooling fixes thin-walled parts by vacuum adsorption.The main body support element has two degrees of freedom,which can be completed.The clamping shape of the free-form surface parts;the structural mechanics calculation and finite element simulation calculation of the key components in the tooling;finally calculating the stiffness of the thin-walled parts under the tooling fixture and verifying by finite element simulation.3)Open-loop control simulation for electromagnetically variable stiffness joints,and obtain the relationship between voltage and output stiffness;apply different control principles to design various control strategies for variable stiffness joints,including traditional PID control,BP neural network PID control and fuzzy PID control,The control parameters of each control strategy are obtained through simulation and the optimal control strategy is obtained.4)Build and carry out the engraving experiment: offline programming simulation of the engraved system before the experiment,the robot working code is obtained,and the engraving force is simulated.Three sets of engraved experiments were designed,which were known surface engraving experiments,unknown convex surface engraving experiments and unknown free-surface engraving experiments.The end contact force during the engraving process was recorded,and the movement trajectory and the underlying metal were scratched.