Research On Robotic Grinding And Polishing Technology For Complex Curved Surface

Impeller is a part of compressor,the blade on the impeller is large and the distance between the two blades is narrow,it is easy to interfere during grinding and polishing.At present,most of the blade surface is still in the stage of manual grinding and polishing,which will make the surface accuracy uneven and increase the defective rate.Aiming at the difficulties of grinding and polishing,this paper uses robot automatic grinding and polishing impeller blades to replace manual grinding and polishing,proposes the minimum curvature method to plan the grinding and polishing trajectory,so as to ensure that the robot has less vibration in the process of grinding and polishing;proposes the method of selecting multiple grinding and polishing points to prove the accessibility of robot grinding and polishing;proposes the method of establishing envelope model for grinding and polishing tools to solve the problem of grinding and polishing interference,Therefore the robot can grind and polish the impeller blade surface.The main research contents are summarized as follows:(1)According to the three-dimensional model of the impeller blade and the grinding and polishing requirements,the robot automatic grinding and polishing platform is built.At the same time,according to the narrow distance between the two blades,the suitable grinding and polishing belt machine is selected,which can make it deep into the two blades for grinding and polishing.It proves that the built grinding and polishing system platform and the selection of grinding and polishing belt machine are reasonable.(2)The coordinate transformation of robot is analyzed,and the sketch of robot coordinate transformation is established.According to the D-H parameters of the robot,the forward and inverse kinematics of the robot are calculated,and the initial pose and the rotation angle of each joint are obtained.By selecting twelve points covering the blade surface on the grinding and polishing workpiece,the robot moves to the selected points in turn,which proves the reachability of the robot.(3)The selection and planning methods of robot grinding and polishing trajectory line are compared,and the robot motion along the trajectory line is simulated,which proves the rationality of the grinding and polishing trajectory line based on the minimum curvature line method proposed in this paper.In order to solve the problem of interference between two blades,the envelope model of grinding and polishing tool is proposed.It is found that the grinding and polishing tool can realize non-interference grinding and polishing in a certain deflection angle range,which provides a reference for robot grinding and polishing impeller blade trajectory planning and non-interference grinding and polishing.(4)The motion analysis experiment of robot grinding and polishing impeller blade is carried out.The accessibility of robot in the process of grinding and polishing and the change of grinding and polishing force when the robot moves along different trajectory lines are mainly analyzed.Firstly,twelve points which can basically cover the whole blade are selected on the blade to be polished,so that the robot can move to these points respectively,which proves the reachability of the robot.The robot is controlled to move on the trajectory line based on the edge line method and the minimum curvature method respectively,and the change amplitude of grinding and polishing force is detected under these two motion states.The results show that the change amplitude of grinding and polishing force is small when the robot moves on the trajectory line based on the minimum curvature method,which provides an important reference for robot grinding and polishing impeller blade trajectory planning.