Automatic maintenance on flight control actuators using collaborative robotics and computer vision.

The Electro-Hydraulic Servo Actuator (EHSA) is the leading technology used for primary flight control on passenger aircraft. As such, they have been the subject of numerous studies for years in the aviation industry, in the field of advanced diagnostics. This thesis work is the result of a nine months experience spent in Lufthansa Technik AG (LHT) facilities in Hamburg. This company is investing in advanced diagnostic program merged with so-called Industry 4.0 in the field of aircraft maintenance. The research project is mainly focused on the development of automatic procedures for adjustments on primary flight control servo actuators using collaborative robotics and computer vision. These test procedures are provided by the Component Maintenance Manual (CMM) of each actuator. To carry out this goal on the EHSA is used a program called RoboLV coded in LabVIEW, a software developed by National Instruments (NI). With this software, it is possible to read specific parameters coming from the robot and command it from an external computer via TCP/IP protocol. In addition to having a user-friendly interface, RoboLV allows programming translations and rotations in the robot's software and setting each command for the tests on a sequencer, building the core of the program on it. In so doing, it is possible to bypass the robot software partially, defining a more flexible program that can be used for different tasks. This approach guarantees to LHT the flexibility to be able to control different robot models, measurement system and servo actuators with the same main program developed in LabVIEW. This strategy makes the time required to program a new robot or adjust unserviceable servo actuator to be drastically reduced, increasing the productivity of the company and building a "smart factory". The servo actuator studied in this thesis is the elevator of the Airbus A320. Three automatic procedures have been developed for adjusting the piston's null position, the recentering device's saturation limits and the RVDT's null position. After debugging and optimising procedures, a small experimental campaign was carried out on three different units. By analysing the results obtained, it has been possible to highlight the critical points inherent in these procedures, aiming to resolve them in possible future developments.