A Mobile Climbing Robot for High Precision Manufacture and Inspection of Aerostructures

In this paper we describe the design, development, and experimental trials of a climbing robot for manufacturing and inspection applications within the aerospace industry. We describe the mechanical platform, which utilizes vacuum for attachment to vertical and overhanging surfaces, and a traction system that enables rapid movement of the robot over planar and curved surfaces of any orientation. The main applications considered during the research were the manufacturing processes for large external surface structures such as wings and the post-manufacturing and in-service inspection of such structures. The design of suitable tool packages for manufacturing and non-destructive testing is considered in the paper. The first tool package to be implemented and tested was a five-axis high precision drill, which is described. The control system is described within this paper along with the software architecture. The software architecture for the robot was generalized, allowing different robot configurations to be described and implemented rapidly through structured configuration files. Particular attention is paid to the robot’s localization and navigation system, which provides tool point precision to aircraft manufacturing tolerances. The localization system uses data from several different types of sensors and combines these with information provided by a surface model to derive six-degrees-of-freedom position and orientation using an extended Kalman filter to fuse the state information from the different sources. Tool point position is calculated through direct kinematic transformations. Improvements to this work are described, which utilize one of the initial releases of Lieca’s new six-degrees-of-freedom precision measurement instruments, the Lieca LTD-800. We also summarize the experimental trials and the initial performance in terms of tool point precision and climbing performance. The concept of application of the robot and details of the technologies included in the robot that are outlined in this paper are the subject of separate pending patent applications filed by BAE SYSTEMS plc.