Design And Analysis Of A Spraying Robot For Large-dimension Aircraft Components

The continuously growing civil aviation market challenges the aero manufacturing industry, as well as provides a great opportunity. Among many processes, spraying(or spray painting) is an extremely important one. However, in the area of spraying large-dimension aircraft components, manual operation is still in the dominance. For kinds of shortcomings, manual spraying cannot meet the requirements of high efficiency and high quality demanded by the contemporary aero manufacturing any more. The introduction of robot technology into the aircraft coating lines has become an unavoidable development trend. Though spraying robots have been invented before, they were mainly serial robots which are of low precision, low stiffness, heavy weight and unfriendliness in explosion proof. With the study of PKM(parallel kinematic machines) getting deeper, designers now have more choices on robotic mechanisms. Parallel robots or even hybrid robots become more and more popular.The purpose of this thesis is to design a new kind of spraying robot used for large-dimension aircraft components and then conduct kinematic and dynamic analysis regarding the robot.Four major parts of research are included in this thesis: a) The designing of the spraying robot is based on the typical serial manipulator. By adding three parallel four-bar linkages, a hybrid spraying robot is synthesized. To design its key dimensions, we consider transmission characteristic of the mechanism and define a dexterous workspace. The length of the robot’s arms is optimal-designed constraint to the condition that dexterous workspace must contain task space. b) On the kinematic analysis, this thesis converts the hybrid robot into an equivalent serial one. Therefore, D-H method is adopted to investigate the functional relationship between the position/posture of the sprayer and the driving variables. After that, Monte Carlo method is used to express the dexterous workspace of the spraying robot in 3D space. c) This thesis will also establish the deposition model of coating materials in order to regulate processing parameters. For the workpiece to be sprayed, a trajectory is planned. d) Following the trajectory we planned, the driving force/torques are derived after deriving the Lagrange equations of the spraying robot.The spraying robot proposed in this thesis changed the layout of the actuators. All the motors are located far away from the sprayer, which helps to increase the safety performance of the spraying robot. In addition, through the kinematic analysis, trajectory planning and dynamic analysis of the spraying robot, the general principles of the spraying robot on kinematics and dynamics are figured out. The research in this thesis lays a solid foundation for the further study and implement of the spraying robot in industrial application.