Development of new health features and automation of tests for primary flight control actuators using a collaborative robot

The commercial aviation in the last twenty years has doubled the Revenue Passenger Kilometers (RPKs), and forecast estimates the global fleet will be almost the double over the next 20 years. In this competitive market, Maintenance, Repair and Overhaul (MRO) industry will demand innovative solutions, a key role to sustain such increase will be the digitalization and automation of the maintenance procedure, such as: integration of collaborative robot, collecting data, connected tools and machine learning. Those innovating tools, are applied in order to create an advanced diagnostic for primary flight control, where the Electro-Hydraulic Servo-Actuator (EHSA) is the most spread technology that is used. This M.Sc thesis, is the result of over nine months of research activity carried out at Lufthansa Technik AG (LHT) facilities, in Hamburg, in collaboration with Politecnico di Torino. The chapter 1, is the motivation of the work, describing why the case of study is the A320 family with the elevator as Unit Under Test (UUT). Moreover, a brief overview of the global market forecast is presented. The chapter 2, describes the Hydiag laboratory focusing on the measurement chain, such as: the hydraulic supply, measurement hardware and all sensors used (LVDT;RVDT; Force Load; Incremental Sensor etc). The chapter 3, starts with a brief description of flight controls and hydraulic system of the A320 family. Then, the last part is geared to the Electro-Hydraulic Servo-Valve (EHSV) and elevator EHSA, with a detailed description of the EHSV first stage and an academic scheme of the complicated re-centering mechanism, which helps the lecture to understand the general function of this mechanism and the further chapters. The chapter 4, concerns the automation of maintenance, adjustment procedures, the first part gives a brief description of the Universal Robot 10 (UR10), then, is given an explanation why the adjustment tests have to be done following a precise order. The last part, starts with the description how the communication between the automatic algorithm, UR10 and UUT works, then, is focused on the description of the three automatic algorithms with flowchart and descriptions. The chapter 5, describes how the new robotic health feature of the recentering device is extracted, moreover, are shown three different methods to obtain the goal current of recentering device’s gain adjustment, and an evaluation of the best method is made. In the last part, are shown several physical descriptions of some interesting behaviour that were found out, explained in detail with schemes and data collected. The chapter 6, introduces some improvement to the actual Component Maintenance Manual (CMM) troubleshooting that regards the automatic adjustment procedure shown in chapter 4, adding new possible fault and try to isolate them. The last part, is a preliminary concept of the final certification, comparing the actual Hydiag entry test with two visions as final certification.