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Reliable Electromechanical actuator for PRImary SurfacE with health monitoring

Periodic Reporting for period 3 - REPRISE (Reliable Electromechanical actuator for PRImary SurfacE with health monitoring)

Reporting period: 2019-04-01 to 2019-12-31

In the past years, several industrial programmes have initiated the concept of a More Electric Aircraft in order to reach objectives of reduced environmental emissions and noise. In fact, there is a general consensus in the aerospace community that more electrically powered systems will lead to weight saving, reliability improvement and life-cycle cost reduction. Therefore, the use of electromechanical actuation (EMA) can be a solution to help the development of a cleaner aviation because, with respect to traditional hydraulic actuation, it is:
• Less complex because of the absence of a hydraulic system
• Better suited to long term storage since there is no leak potential
• More energy efficient compared with hydraulic systems
• Easier to install and maintain (no filtration, no bleeding)
• Less complex to control from a power-distribution and power-management perspective (power is transmitted without mass transfer)
Nevertheless, some critical issues of this technology need to be addressed. Based on this scenario, the REPRISE project is specifically focused on overcoming these issues and improving technology performance, reliability and safety using new technologies and health-management algorithms. Main technical objectives are as follows:
• An innovative electromechanical actuator (EMA) for flight-control surfaces with reduced spatial envelope and weight and with improved reliability
• Reliable health-management software for the electromechanical actuator to increase safety margins
The project is divided into 6 work packages (WP). WP1 is related with project management and dissemination of results. About dissemination activities, four technical paper were prepared and presented at international conferences, one paper was submitted to the IEEE Transaction of Industrial Electronics journal, and two book chapters were submitted for evaluation by Springer.
Other work packages are related to RTD activities and can be grouped into two main parts:
a. The first stage (WP2-WP3) was completed in the first reporting period and was focused on the preparation of the test bench, on the design of the experimental procedure and the test reporting.
b. The second part (WP4-WP5-WP6) started in the first reporting period but will be completed in the second and third one. This phase is devoted to the design of the health monitoring system (WP4), to the improvement of the current EMA design (WP5) and to experimental validation of the research activities (WP6).
In term of technical progress, the following main achievements must be highlighted for each WP.
Related to WP2:
- Development and manufacturing of the test rig for the first phase of test on the current EMA
- Failure Mode and Effect Analysis executed on the EMA similar to the one used for the first phase of test
- Definition of test procedure suitable to verify if and how mechanical degradation on transmission components (like ball screws and bearings) of the EMA under test can be monitored in real time
Related to WP3:
- First phase of test completed
- Identification of the mechanical failures features in order to perform clear and robust fault identification
- Understand how the EMA malfunction affords the operations within the acceptable conditions
- Collection of useful data for the development of change-detection algorithms.
Related to WP4:
- Definition of requirements of health monitoring system
- Simulation analysis and health monitoring software development. Two methods have been developed: one based on change-point detection is currently under SW implementation. The second is based on statistical process monitoring.
- Evaluation of sensors for health monitoring system
Related to WP5:
- Evaluation of new technologies and architecture in the design of an upgraded EMA with the aim to increase reliability and safety and reduce mass and envelope.
- Update of requirements to include a new fault-tolerant architecture for the EMA
- Design of fault-tolerant EMA. PDR was completed. CDR was closed in June 2019.
- Manufacturing and test of a preliminary prototype to validate the proposed concept
- Manufacturing of the final prototype
- FInalization of sensors design
Related to WP6:
- Definition of new test procedures for base configuration actuator in order to enhance the health monitoring algorithm performance;
- Definition of new position reference signals in order to better excite the system.
- Performing of test on the base configuration actuator according to the procedure cited above.
- Inspection of actuator with non-destructive methods
- Post-processing of data and development of the HM system SW
The aim of REPRISE research activities is to advance the state-of-the-art in electrical actuation and in actuators’ health monitoring. These are instrumental in enabling a thorough validation of the equipment and units. Significant technological breakthroughs in the scope of the project are expected to be:
• Develop flight-representative (TRL5), electromechanical actuators able to fit within the limited envelope foreseen for their application in thin wings
• Overcome the critical issue of possible seizure of electromechanical actuators, while enhancing their reliability by means of a combination of actuator architectures with a minimum number of components, employing health monitoring system .
• Introduction and evaluation of new types of sensors that are more reliable and smaller in size and weight than current health-monitoring sensors.
• Develop the optimal architecture for a diagnostic and health-management system for electromechanical actuator that will maximise its cost effectiveness.
These technological results will contribute to foster the competitiveness of European aviation through cost efficiency and innovation. In particular, they will:
• Contribute to the development of a new generation of SMALL aircraft with better handling qualities, reduced fuel consumption and lower operating and life-cycle costs
• Provide a contribution in establishing market leadership for the European aviation stakeholders in electric actuation for critical aircraft systems and in the associated flight-control systems, as well as in health-management systems
• Introduce a new fault tolerant architecture in order to increase safety, to reduce costs associated with non-operational aircraft status