Research On The Quality Control Method Of Robotic Drilling System

The missile launcher and the vehicle are connected by thread.Due to the structural size of the missile launcher,the traditional machine tool can not meet the requirements of hole making.It has the disadvantages of low processing efficiency and unstable processing quality,and does not accord with the current trend of automation and intelligent manufacturing of aerospace equipment.The robot hole making has the characteristics of large processing flexibility,wide processing range and strong versatility,which can meet the requirements of missile launching barrel hole making.However,due to the weak rigidity caused by the multi-link series structure of industrial robots,the robot hole making system is prone to structural deformation and chatter under the action of drilling force in the process of hole making,which will affect the hole making quality of the robot hole m aking system.In order to explore the influence of the stiffness of the robot pore-making system on the pore-making quality,this paper starts from the stiffness modeling of the robot pore-making system,and analyzes the action law of the change of the stiffness of the robot pore-making system on the pore-making quality through statics and dynamics,so as to lay the technical foundation for the closed-loop control of the pore-making quality of the robot pore-making system.The main research achievements of this paper are as follows:(1)The quality control experiment platform of the robot hole making system is built.In order to improve the end stiffness of the robot hole making system,a pressing device was integrated on the end effector,and the function relationship between the control signal and the pressing foot pressure was established through the pressure calibration experiment,which realized the precise control of the pressing force of the pressing foot.In order to improve the friction state between tool and workpiece,a micro-lubrication system is integrated into the robot hole making system to solve the problem of difficult lubrication in the process of automatic hole making.(2)The stiffness model of the robot under the action of the press foot i s established.Firstly,the kinematics model of the robot is established through the kinematics analysis,and the Jacobian matrix of the robot is derived based on the kinematics model by the vector product method.Secondly,the ellipsoid of robot end flexibility was established by Jacobian matrix and joint stiffness matrix,and the mapping relationship between joint Angle and end stiffness was obtained.Finally,the equivalent stiffness of the cylinder is solved by modeling the cylinder stiffness,and the s tiffness enhancement mechanism of the robot hole system under the action of the press foot is analyzed.(3)The influence law of drilling force and robot stiffness on hole making quality was analyzed by dynamic model.The process parameters were optimized from two aspects of improving the end stiffness of robot hole making system and reducing the disturbance of cutting force to improve the machining quality.The experimental results show that the proposed robot hole quality control method can effectively improve the hole quality of the robot hole system.The average machining precision of the hole is increased by 0.98 mm,the average roundness of the hole is increased by 0.036 mm,and the average height of the outlet burr is decreased by 74.3%.