Design And Research Of Robot Drilling End Effector Control System

As flexible manufacture equipment, robot drilling system is widely used abroad and begin to achieve benefits, due to its high flexibility and low cost. It is not only applied to mass production, but also can quickly adapt to products upgrading and fit small batch production or the development stage of the assembly production. However, robot drilling system is few used at home. The performance of automatic drilling is mainly achieved by the introduction of automatic drilling and riveting machines abroad. Against this background, the project group of Aircraft Digital Assembly in Zhe Jiang University has developed a robot drilling system based on the drilling of aircraft panels. This paper presents the design and research of robot drilling end effector control system.The first chapter presents the research background and meaning of this paper firstly. And then the recent development of automatic drilling system in aircraft digital assembly is summarized both at home and abroad. At last, the research contents are presented based on the introduction of the apppplication of robot drilling system and its end effector in aircraft assembly.In the second, firstly, the drilling process and requirements of aircraft panels are presented. And then the robot drilling system is introduced based on the drilling of end effector, each constituent's structure, function and characteristics of the system are introduced in detail. Finally, the drilling process and characteristics of robot drilling system are analysed.In the third chapter, the feeding system's control principles of the end effector are introduced at first. The control system based on SynqNet is presented from the design requirements of the control system. And the hardware constituents of the system are introduced in detail at the same time. Then the full closed loop control way of the feeding shaft is chose according to the transmit principle of the feeding system. And also the PID controller of the current loop velocity loop and position loop in AC servo control system are both designed. Finally, the control system of the spindle motor is introduced. It is a great challenge to ensure the countersink depth of robot drilling due to the deformation and vibration of the workppiece during the drilling process. The fourth chapter presents the feeding shafif's full closed loop control system, based on the pressure foot's real-time position compensation of the end effector. The displacement of the pressure foot is equal to the deformation of the workppiece during the drilling process and added to the countersink depth on real time. A lowpass filter is designed to restrain the interference to position control caused by pressure foot's high frequency vibration. Thereby ensure the countersink depth and achieve high hole quality. At last, the implementation process of the control system in MechaWare is introduced.In order to prove the feasibility of the end effector's control system and check the control effect of the countersink depth, couples of experiments are set up in the fifth chapter in allusion to different drilling, surface pressure force and different specification of cut tools. According to the analysis of experimental results, the end effector's feeding system with real-time position compensation of the pressure foot can make the hole quality very accurate, with the countersink depth variation at 0.02 mm in the worst case. Compared to hand-drilling, the roundness, roughness and drilling efficiency of the hole has been greatly improved.The research work is summarized and the further studies are prospeted in the sixth chapter.