Design and implementation of a robotic laser paint removal system

Abstract:

Traditional chemical cleaning, mechanical sanding, and sandblasting can produce large volumes of hazardous waste and damage the substrate. In addition, the depainting process is low-efficient and labor-intensive. Based on the aircrafts structural shape and paint removal requirements, a robotic laser paint removal system for aircraft maintenance is developed. The robotic laser paint removal system contains the omnidirectional moving unit, the four-degree-of-freedom robot arm unit, the laser cleaning unit, and the measurement and control unit. Firstly, the mechanical structure and control architecture of the laser paint removal robot are designed, based on the shape of the DR-5 unmanned aerial vehicle (UAV), and the robot arms kinematic analysis. Workspace analysis is carried out using the D-H method to verify the reachability of the robot arm. Secondly, the robot arm is tested for repeatability, where the Z-direction repeatability is quantitatively evaluated using laser displacement sensors, and the X andY-direction repeatability is evaluated using an error circle. Finally, based on the bow path, the laser paint removal test is carried out on part of the flat surface and the curved surface of the UAV fuselage. Moreover, the paint removal result is evaluated according to the residual thickness of the surface paint layer. The results show that the repeatability of the laser paint removal robot is 0.039 mm in Z-direction and less than ±2.000 mm in the X and Y-directions; the average residual thickness of the flat surface paint removal experiment is 6.5 μm and the average residual thickness of the curved surface paint removal experiment is 21.3 μm.