An innovative normal self-positioning method with gravity and friction compensation for wall-climbing drilling robot in aircraft assembly

Abstract

Abstract In aircraft manufacturing, the normal accuracy of fastening holes is crucial for the performance and lifetime of the aircraft. However, industrial robots face challenges in achieving precise normal positioning, marked by insufficient rigidity and error amplification. Contemporary methodologies frequently rely extensively on external sensors, encountering limitations in the presence of spatial constraints and low-light conditions. In response to these challenges, this paper presents a wall-climbing drilling robot specifically designed for operation within confined spaces. It innovatively employs an expansion self-positioning mechanism, coupled with robotic joint torque compensation control, to achieve precise normal positioning. The methodology relies on established drilling templates to determine hole positions and normals. By coordinating machinery and control efforts, the robot spindle axis aligns precisely with the axis of the drilling template sleeve, ensuring accurate normal positioning. The paper provides a comprehensive analysis of the mechanical principles governing the expansion self-positioning of the robot and introduces the joint torque compensation control method. The accuracy and effectiveness of the proposed approach are rigorously validated through a series of meticulous drilling experiments. Results demonstrate a significant improvement in the drilling normal accuracy of the wall-climbing drilling robot, meeting the stringent requirements for normal accuracy in aircraft assembly holes.