scholarly journals A Case Study on the Detection and Prognosis of Internal Leakages in Electro-Hydraulic Flight Control Actuators

Actuators ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 215
Author(s):  
Antonio Carlo Bertolino ◽  
Andrea De Martin ◽  
Giovanni Jacazio ◽  
Massimo Sorli
Keyword(s):  
Flight Control ◽  
Particle Filtering ◽  
Health Management ◽  
State Of The Art ◽  
Commercial Aircraft ◽  
Flight Data ◽  
Prognostic System ◽  
Hydraulic Servo ◽  
Definition Of

Electro-hydraulic servo-actuators (EHSAs) are currently considered the state-of-the art solution for the control of the primary flight control systems of civil and military aircraft. Combining the expected service life of a commercial aircraft with the fact that electro-hydraulic technology is employed in the vast majority of currently in-service aircraft and is planned to be used on future platforms as well, the development of an effective Prognostic and Health Management (PHM) system could provide significant advantages to fleet operators and aircraft maintenance, such as the reduction of unplanned flight disruptions and increased availability of the aircraft. The occurrence of excessive internal leakage within the EHSAs is one of the most common causes of return from the field of flight control actuators, making this failure mode a priority in the definition of any dedicated PHM routine. This paper presents a case study on the design of a prognostic system for this degradation mode, in the context of a wider effort toward the definition of a prognostic framework suitable to work on in-flight data. The study is performed by means of a high-fidelity simulation model supported by experimental activities. Results of both the simulation and the experimental work are used to select a suitable feature, then implemented within the prognostic framework based on particle filtering. The algorithm is at first theoretically discussed, and then tested against several degradation patterns. Performances are evaluated through state-of-the-art metrics, showing promising results and providing the basis towards future applications on real in-flight data.

scholarly journals Results of a Feasibility Study of a Prognostic System for Electro-Hydraulic Flight Control Actuators

2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Sylvain Autin ◽  
Andrea De Martin ◽  
Giovanni Jacazio ◽  
Jérôme Socheleau ◽  
George Vachtsevanos
Keyword(s):  
Control Systems ◽  
Feasibility Study ◽  
Flight Control ◽  
The Novel ◽  
Flight Control System ◽  
Commercial Aircraft ◽  
Prognostic System ◽  
Effective Technology ◽  
Hydraulic Servo ◽  
Commercial Aircrafts

Electro-Hydraulic Servo-Actuators (EHSA) are currently the most used actuation technology for primary flight control systems of civil and military aircrafts. Although some alternatives have emerged in the last decade, such as electromechanical or electro-hydrostatic solutions, electrohydraulic systems are still considered the most effective technology in flight-critical application of new commercial aircrafts. Moreover, the vast majority of aircraft currently in service are equipped with this technology. Considering the number of actuators typically employed in a primary flight control system and the expected service life of a commercial aircraft, the development of an effective PHM system could provide significant benefits to fleet operators and aircraft maintenance. This paper presents the results of a feasibility study of such a system for electro-hydraulic actuators used in fly-by-wire primary flight control systems, considering the actuator of a wide body commercial aircraft as use case. Aim of the research is the implementation of a PHM system without the addition of dedicated sensors, solution which would allow for the application of the proposed prognostic solution on both new and existing platforms. This paper describes the methodology and the results of the feasibility study through simulation and experimental activities, which shows how the novel PHM technologies proposed for a PHM system for the EHSAs of primary flight control actuators can allow the migration from scheduled to condition-based maintenance.

A Simulation Survey on the Effects of Progressing Faults Within the SCAS of a Flight Control Actuator for Helicopters

2021 ◽  
Author(s):  
Andrea De Martin ◽  
Giovanni Jacazio ◽  
Massimo Sorli ◽  
Giuseppe Vitrani
Keyword(s):  
Flight Control ◽  
Health Management ◽  
Risk Mitigation ◽  
Selection Process ◽  
Stability Control ◽  
Features Selection ◽  
Vertical Walls ◽  
Low Altitude ◽  
Definition Of ◽  
Rotary Wing

Abstract Stability Control Augmentation Systems (SCAS) are widely adopted to enhance the flight stability of rotary-wing aircraft operating in difficult aerodynamic conditions, such as low altitude missions, stationary flight nearby vertical walls or in presence of heavy gusts. Such systems are based upon small electro-hydraulic servosystems controlled in position through a dedicated servovalve. The SCAS operates with limited authority over the main control linkage translating the pilot input in the movement of the main flight control actuator. Being critical for the operability of the helicopter, the definition of a Prognostics and Health Management (PHM) framework for the SCAS systems would provide significant advantages, such as better risk mitigation, improved availability, and a reduction in the occurrences of unpredicted failures which still represent one of the most known downsides of helicopters. This paper provides the results of a preliminary analysis on the effects of the inception and progression of several degradation types within a simulated SCAS system. Signals usually available within such devices are hence combined with measurements provided by additional sensors to check the feasibility of a PHM system with and without dedicated sensors. The resulting features selection process shows that although the dedicated measurements are required to design a complete PHM system, it appears nonetheless possible to obtain valuable information on the health status of the SCAS system without resorting to additional sensors.

scholarly journals Feasibility Study of a PHM System for Electro-hydraulic Servo-actuators for Primary Flight Controls

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
Sylvain Autin ◽  
Jérôme Socheleau ◽  
Andrea Dellacasa ◽  
Andrea De Martin ◽  
Giovanni Jacazio ◽  
...  
Keyword(s):  
Control Systems ◽  
Feasibility Study ◽  
Flight Control ◽  
Particle Filtering ◽  
Remaining Useful Life ◽  
Research Activity ◽  
Ongoing Research ◽  
Flight Controls ◽  
Aircraft Flight Control ◽  
Hydraulic Servo

Electro-Hydraulic Servo-Actuators (EHSA) are by far the mostly used type of actuators in aircraft primary flight control systems. Though electrical actuation is been considered since long as a possible replacement of hydraulic actuation for aircraft systems, EHSAs are still the technology of choice in the primary flight control systems of new commercial aircrafts. Considering that 10 or more EHSAs are typically used in an aircraft flight control system, the development of an effective PHM system for this equipment could provide large benefits and be of great interest for the OEMs and for the air fleet operators. This paper presents the results of a feasibility study making up the first part of an ongoing research activity focused on the development of a PHM system for EHSAs used in fly-by-wire primary flight control systems and takes as a use case the primary flight control actuator of a wide body commercial aircraft. One of the key features of the research is the implementation of a PHM system without the addition of new sensors, taking advantage of the available signals. This offers the possibility of implementation of the PHM system on the existing platforms and not only as a proposition for new aircrafts designed with a complement of additional sensors. The enabling technologies for this PHM system borrow from the area of Bayesian estimation theory and specifically particle filtering and the information acquired from EHSA in-flight and during pre-flight check is processed by appropriate algorithms in order to obtain relevant features, detect the degradation and estimate the Remaining Useful Life (RUL). The results are evaluated through appropriate metrics in order to assess the performance and effectiveness of the implemented PHM. This paper describes the methodology of the feasibility study, which shows how the novel PHM technologies proposed for a PHM system for the EHSAs of primary flight control actuators can allow the migration from unscheduled / on-condition maintenance to condition based maintenance targeting the perceived objectives of the OEM and of the aircraft operator.

scholarly journals Control design and state of the art for fly-by-wire systems

2021 ◽  
Author(s):  
Sean A. J. Lahey
Keyword(s):  
Flight Control ◽  
State Of The Art ◽  
Control Design ◽  
The State ◽  
General Level ◽  
Hydraulic Actuator ◽  
Servo Valve ◽  
Aircraft Flight ◽  
Aircraft Flight Control ◽  
Hydraulic Servo

The report discusses the design and operation of electro-hydraulic servo-valves, illustrates a basic contol implementation design for an electro-hydraulic servo-valve controlled hydraulic actuator [for aircraft flight control actuation] and provides a survey of the state of the art of flight control of aircraft using fly-by-wire (FBW) architecture. The electro-hydraulic servo-valve figures prominently in typical FBW implementations and is an essential part of a modern aircraft flight control system. The scope of this report represents a large area of research, presented at a general level, and serves as a general summary of technologies and considerations for modern aircraft control. Fly-by-wire provides many advantages over traditional forms of aircraft flight control, and it represents both the state of the art in this area and also the future of almost all civilian and military aircraft flight control. The architecture, characteristics and control design relating to electro-hydraulic servo-valve controlled actuators is discussed in the report. The application of such actuators to fly-by-wire implementation is discussed in some depth, and the process by which fly-by-wire systems are developed is discussed.

A Generic Approach for Assessing Compatibility Between Task Descriptions and Interactive Systems: Application to the Effectiveness of a Flight Control Unit

i-com ◽  
2015 ◽  
Vol 14 (3) ◽  
Author(s):  
Camille Fayollas ◽  
Célia Martinie ◽  
David Navarre ◽  
Philippe Palanque
Keyword(s):  
Flight Control ◽  
Development Process ◽  
Control Unit ◽  
Interactive Systems ◽  
Application Integration ◽  
Interface Elements ◽  
Interactive Applications ◽  
Interactive Application ◽  
Definition Of

AbstractTask models are a very powerful artefact describing users’ goals and users’ activities and contain numerous information extremely useful for designing usable interactive applications. Indeed, task models is one of the very few means for ensuring effectiveness of the application i. e. that the application allows users to reach their goals and perform their tasks. This paper presents a tool-supported framework for exploiting task models throughout the development process and even when the interactive application is deployed and used. To this end, we introduce a framework for connecting task models to an existing, executable, interactive application. The main contribution of the paper lies in the definition of a systematic correspondence between the user interface elements of the interactive application and the low level tasks in the task model. Depending on the fact that the code of the application is available or not, the fact that the application has been prepared at programming time for such integration or not, we propose different alternatives to perform such correspondence (in a toolsupported way). This task-application integration allows the exploitation of task models at run time bringing in the benefits listed above to any interactive application. The approach, the tools and the integration are presented on a case study of a Flight Control Unit (FCU) used in aircraft cockpits. This paper extends the article entitled ‘A Generic Tool-Supported Framework for Coupling Task Models and Interactive Applications’ which have been presented at the 7

scholarly journals Detection and Prognosis of Propagating Faults in Flight Control Actuators for Helicopters

Aerospace ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 20 ◽  
Author(s):  
Andrea Nesci ◽  
Andrea De Martin ◽  
Giovanni Jacazio ◽  
Massimo Sorli
Keyword(s):  
Flight Control ◽  
Particle Filtering ◽  
Failure Modes ◽  
Selection Process ◽  
Critical Systems ◽  
Maintenance Policy ◽  
Prognostic System ◽  
Diagnosis And Prognosis ◽  
Failure Prognosis ◽  
Depth Feature

Recent trend in the aeronautic industry is to introduce a novel prognostic solution for critical systems in the attempt to increase vehicle availability, reduce costs, and optimize the maintenance policy. Despite this, there is a general lack of literature about prognostics for hydraulic flight control systems, especially looking at helicopter applications. The present research was focused on a preliminary study for an integrated framework of fault detection and failure prognosis tailored for one of the most common architectures for flight control actuation. Starting from a high-fidelity dynamic model of the system, two different faults were studied and described within a dedicated simulation environment: the opening of a crack in the coils of the centering springs of the actuator and the wear of the inner seals. Both failure modes were analyzed through established models available in the literature and their evolution simulated within the model of the actuator. Hence, an in-depth feature selection process was pursued aimed at the definition of signals suitable for both diagnosis and prognosis. Results were then reported through an accuracy-sensitivity plane and used to define a prognostic routine based on particle filtering techniques. The more significant contribution of the present research was that no additional sensors are needed so that the prognostic system can be potentially implemented for in-service platforms.

scholarly journals Design of a PHM system for electro-mechanical flight controls: a roadmap from preliminary analyses to iron-bird validation

2019 ◽  
Vol 304 ◽  
pp. 04018 ◽  
Author(s):  
Andrea De Martin ◽  
Giovanni Jacazio ◽  
Massimo Sorli
Keyword(s):  
Fault Diagnosis ◽  
Control Systems ◽  
Flight Control ◽  
Management System ◽  
Health Management ◽  
Prognostics And Health Management ◽  
Case Scenario ◽  
Flight Controls ◽  
Definition Of ◽  
New Algorithms

Literature on PHM is focused on research dedicated to the definition of new algorithms to achieve better failures prognosis or earlier and more accurate fault diagnosis, but lacks of examples on the design of novel PHM frameworks and the practical issues related with their implementation. This paper describes a roadmap for the design of a novel Prognostics and Health Management system while making reference to a real-case scenario applied to electro-mechanical actuators for flight control systems.

scholarly journals Windings Fault Detection and Prognosis in Electro-Mechanical Flight Control Actuators Operating in Active-Active Configuration

2020 ◽  
Vol 8 (2) ◽  
Author(s):  
Andrea De Martin ◽  
Giovanni Jacazio ◽  
George Vachtsevanos
Keyword(s):  
Anomaly Detection ◽  
Flight Control ◽  
Particle Filtering ◽  
Performance Metrics ◽  
Health Management ◽  
Production Costs ◽  
Partial Replacement ◽  
Slow Increase ◽  
Safety Issues ◽  
Novel Approach

One of the most significant research trends in the last decades of the aeronautic industry is the effort to move towards the design and the production of “more electric aircraft”. Within this framework, the application of the electrical technology to flight control systems has seen a progressive, although slow, increase: starting with the introduction of fly-by-wire and proceeding with the partial replacement of the traditional hydraulic/electro-hydraulic actuators with purely electro-mechanical ones. This evolution allowed to obtain more flexible solutions, reduced installation issues and enhanced aircraft control capability. Electro-Mechanical Actuators (EMAs) are however far from being a mature technology and still suffer from several safety issues, which can be partially limited by increasing the complexity of their design and hence their production costs. The development of a robust Prognostics and Health Management (PHM) system could provide a way to prevent the occurrence of a critical failure without resorting to complex device design. This paper deals with the first part of the study of a comprehensive PHM system for EMAs employed as primary flight control actuators; the peculiarities of the application are presented and discussed, while a novel approach, based on short pre-flight/post-flight health monitoring tests, is proposed. Turn-to-turn short in the electric motor windings is identified as the most common electrical degradation and a particle filtering framework for anomaly detection and prognosis featuring a self-tuning non-linear model is proposed. Features, anomaly detection and a prognostic algorithm are hence evaluated through state-of-the art performance metrics and their results discussed.

scholarly journals Preliminary study towards the definition of a PHM framework for the hydraulic system of a fly-by-wire helicopter

2020 ◽  
Vol 12 (1) ◽  
pp. 13
Author(s):  
Andrea De Martin ◽  
Giovanni Jacazio ◽  
Massimo Sorli
Keyword(s):  
Flight Control ◽  
Hydraulic System ◽  
Preliminary Analysis ◽  
Failure Modes ◽  
Health Management ◽  
Management Approach ◽  
Critical System ◽  
Wide Range ◽  
The Subject ◽  
Definition Of

On-board hydraulic systems are tasked to provide a number of critical functions to ensure the in-flight operability of rotary-wings vehicles; the hydraulic plant is required to supply power to the flight control actuators and utilities, as well as condition the hydraulic fluid, under a wide range of possible in-service conditions. Being a flight-critical system, the definition of a Prognostics and Health Management framework would provide significant advantages to the users, such as better risk mitigation, improved availability and a reduction in the occurrences of unpredicted failures which still represent one of the more known downsides of helicopters. A preliminary analysis on the effects of the inception and progression of several degradation types is the first step towards assessing if such PHM system is feasible, and which failure modes are more likely to be observed. Moreover, since several key components are frequently provided by different suppliers to the airframer, this preliminary analysis would allow to better assess if an Integrated Vehicle Health Management approach, integrating signals coming from different components, could be beneficial. To pursue this study, a complete model of the hydraulic system for a fly-by-wire helicopter has been prepared. Then, an in-depth simulation campaign was pursued with the aim of studying the interactions between different failure modes, the effects that the propagating degradations have on the system performances and which signals can be used to define a robust set of features. The paper introduces the case-study under analysis, a general configuration for fly-by-wire helicopters, presenting the most prominent peculiarities of the system and the effect of such peculiarities on the definition of health monitoring schemes. The model is then used to describe the behavior of the system under nominal and degraded conditions is introduced. Between the possible failure modes, the interaction between wear in several mechanical components and the occlusion of the hydraulic lines filters was chosen as the subject of this study; motivations are provided and the degradation model described in detail. Hence, results of a wide-ranging simulation campaign are presented, where the time-domain response of the system is used to guide in the definition of a proper set of features able to characterize the selected fault cases. Selected features are presented, chosen according to significant metrics such as correlation with the simulated degradations, signal-to-noise ratio and accuracy. Two different approaches with a varying degree of integration between system signals are proposed and compared. Prognostics is then pursued through well-known particle filter algorithms. The analysis provides promising results on the capability of successfully detecting, isolating and identifying the selected fault mode; laying the foundations for further and more comprehensive studies on the subject.

scholarly journals Control design and state of the art for fly-by-wire systems

2021 ◽  
Author(s):  
Sean A. J. Lahey
Keyword(s):  
Flight Control ◽  
State Of The Art ◽  
Control Design ◽  
The State ◽  
General Level ◽  
Hydraulic Actuator ◽  
Servo Valve ◽  
Aircraft Flight ◽  
Aircraft Flight Control ◽  
Hydraulic Servo

The report discusses the design and operation of electro-hydraulic servo-valves, illustrates a basic contol implementation design for an electro-hydraulic servo-valve controlled hydraulic actuator [for aircraft flight control actuation] and provides a survey of the state of the art of flight control of aircraft using fly-by-wire (FBW) architecture. The electro-hydraulic servo-valve figures prominently in typical FBW implementations and is an essential part of a modern aircraft flight control system. The scope of this report represents a large area of research, presented at a general level, and serves as a general summary of technologies and considerations for modern aircraft control. Fly-by-wire provides many advantages over traditional forms of aircraft flight control, and it represents both the state of the art in this area and also the future of almost all civilian and military aircraft flight control. The architecture, characteristics and control design relating to electro-hydraulic servo-valve controlled actuators is discussed in the report. The application of such actuators to fly-by-wire implementation is discussed in some depth, and the process by which fly-by-wire systems are developed is discussed.

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