Research On Contact Control Algorithm And Trajectory Planning Of Free Surface Of Aircraft Thin-Walled Parts

At present,the task of cleaning and polishing of paint on the aircraft skin is mainly executed by manual operation,with high operation intensity,bad working environment and low efficiency.It easily results in pits and overcutting phenomenon on the surface of the skin and the polishing quality seriously depends on the operator's technical level.To overcome these shortcomings and problems,it is a good choice to use robot with six degrees of freedom to replace the manual operation to conduct the task of cleaning and polishing of paint on the aircraft skin.In this paper,the robot kinematics model,the grinding trajectory planning and the grinding force control are studied,which are involved in the process of cleaning and polishing of paint on the aircraft skin with industrial robot with six degrees of freedom.Details are as follows:Firstly,based on the model of FANUC R2000iB₁25L industrial robot with six degrees of freedom,the grinding robot model with five degrees of freedom is obtained.The kinematics model of grinding robot is established by Denavit-Hatenberg method and the positive and inverse solutions of robot kinematics are obtained.MATLAB is used to establish the robot model and simulate positive kinematics and inverse kinematics of robot,which has verified the correctness of the robot model.Secondly,symmetry and asymmetry combined sine function trajectory planning methods have been applied to do the trajectory planning task of the angle,the angle velocity and the angular acceleration of the joints of robot.After comparing the planning effects of the two trajectory planning methods,it shows that two methods have improved the overall motion performance of the robot.What's more,the trajectory planning effect of the asymmetric combined sine function method is better.Finally,the contact issue between the grinding head and the surface of the skin is studied during the actual grinding process.Preston equation has been introduced to obtain the mathematical control model of the grinding force and elastic deformation.The elastic deformation could be compensated to the polishing trajectory to obtain the desired normal grinding force,which provides a theoretical basis for the practical application of the method.