Aircraft Flight Control System Research Articles

Oscillating energy deposition of 17-4 PH alloy reinforced with tungsten carbide particles

17-4 PH is a martensitic precipitation-hardening stainless steel, renowned for its exceptional strength and high-temperature resistance, making it extensively employed in the fabrication of aircraft engines and flight control systems. The strengthening method of this alloy involves precipitation strengthening through thermal treatment. However, it is also susceptible to grain growth, which can diminish the alloy's mechanical properties and corrosion resistance. This research proposes to use circular oscillating laser deposition of 17-4 PH alloy reinforced with tungsten carbide (WC) and compares it with Gaussian laser deposition. The research findings indicate that the circular oscillating laser induces a stirring effect on the molten pool, facilitating the transformation of columnar dendrites into equiaxed grains and thereby refining the grain size. The convection, intensified by the high temperature and stirring effect, promotes the melting and diffusion of WC particles. The reaction between W, C elements, and 17-4 PH alloy facilitates the precipitation of hard phase carbides. Compared to Gaussian laser deposition, the microhardness of the 7 wt% WC/17-4 PH material prepared by circular oscillating laser deposition increased by 21.25 %, and the wear rate decreased by 70.06 %. The electrochemical test results have revealed that the 7 wt%WC/17-4 PH composite material fabricated using Gaussian laser exhibits optimal corrosion resistance. The circular oscillating laser induces carbide deposition at grain boundaries, resulting in the formation of microcells and exacerbating the corrosion.

A Hybrid Health Monitoring Approach for Aircraft Flight Control Systems With System-Level Degradation

This paper proposes a novel hybrid health monitoring approach to monitor the system-level degradation of aircraft flight control systems (FCSs). The idea derives from observing the nonlinear hysteresis phenomenon in FCS. First, a health FCS model is developed to implement the nonlinear degradation signal extraction of FCS by building an adaptive-network-based fuzzy inference system, a data-driven method. Subsequently, the Jump Markov autoregressive exogenous (JMARX) system with time delays is adopted to establish the FCS system-level degradation model. An expectation maximum-convex optimization algorithm is innovatively proposed to identify the model parameters. After that, three health indicators associated with the degradation model parameters are utilized for FCS system-level health monitoring. Finally, a practical flight experiment is conducted by a civil aircraft. The obtained experimental data is used to validate the effectiveness of the proposed FCS monitoring approach. The model of the time-delay JMARX system gets good modeling evaluation results on mean absolute error, standard deviation, etc. Besides, each of the three health indicators shows a clear FCS degradation tendency, which indicates that the proposed method successfully extracts the degradation information and monitors the health states of FCS. This approach is potential for practical and effective engineering applications in the aviation industry.

Automatic take-off control system

The purpose of the work is to present a solution that will significantly contribute to the technological development of the European defense sector. The proposed solution raises the issue of controlling autonomous vehicles. This paper presents the concept of an algorithm that allows for automatic take-off of unmanned aircraft. Arguments are presented which justify the need for developing and applying such a system. The socioeconomic and environmental aspects of the project are also discussed. The automatic take-off algorithm complements existing aircraft flight control systems. The considered solution takes into account take-off as a maneuver made of three phases. The control on a runway is possible due to data fusion from the INS and GNSS systems. Data fusion may be supported by using the runway image processing system. The concept of an automatic take-off algorithm is presented along with the most appropriate testing methods, including software-in-the-loop and hardware-in-the-loop simulations.

The impact analysis of the un-commanded brake caused by pedal jamming on the aircraft

The rudder brake pedal unit is an important part of aircraft flight control system, also is the human machine interface for pilots to control the aircraft rudder and brake. By applying forces at different positions and directions on the pedals, the pilot can realize the rudder control and brake control functions respectively. This paper takes the rudder brake pedal control unit of civil aircraft as the research object. The research process is as follows. Firstly, an analysis about the influence on the compression of brake sensor by operating pedal when the brake pedal jamming is carried out using CATIA. Secondly, the forces acted on aircraft during rolling on the ground are analyzed and the ground dynamic equations are presented. Finally, through the simulation on the engineering simulator of a certain aircraft, the influence of differential brake caused by brake pedal jamming on the aircraft speed after V1 (take-off decision speed) in the take-off phase is verified. The research results of this study show that, the impact of un-commanded differential brake caused by rudder brake pedal jamming on the safety of the aircraft must be considered during the aircraft design process, and effective measures must be taken to avoid the occurrence of un-commanded deceleration after V1 in the take-off phase.

The Integrated-Servo-Actuator Degradation Prognosis Based on the Physical Model Combined With Data-Driven Approach

The integrated-servo-actuator (ISA) is one of the most critical subsystems of aircraft flight-control system, which controls the speed, direction, displacement, and force of load for an aircraft. The degradation state of the ISA directly influences the safety of the aircraft. Hence, it is valuable to predict the degradation of the ISA to ensure its operating reliability. However, as a kind of complex system, the degradation mechanisms and the influences of the stress cannot be fully understood. Moreover, the nonlinear degradation process brings more difficulties to establish an accurate life prognosis model. To address these challenging issues, this paper proposed a hybrid degradation prognosis method that fused the physics-based model and data-driven model for ISA. The nonlinear Wiener process (NWP) algorithm is utilized to characterize the physical degradation process of ISA. The effect of different stresses is quantitatively modeled. Furthermore, the data-driven echo-state-network (ESN) is optimized to describe the nonlinear degradation process of ISA. More degradation data are generated based on the NWP model for ESN model training. Therefore, the degradation trajectory predicting model is fused with the physics-based degradation prognosis model so that both the degradation mechanisms and time series features within the monitoring data are combined. The experimental results based on the real ISA data illustrate that the proposed method has higher prediction accuracy which is meaningful to enhance the operating reliability of the ISA.

Model-driven development for the seL4 microkernel using the HAMR framework

Verified microkernels such as seL4 provide trustworthy foundations for safety- and security-critical systems. However, their full potential remains unrealized due, in part, to the lack of application development environments that help engineers integrate the microkernel’s configuration and hosting of application code with modeling, analysis, and verification tools that address broader aspects of the development lifecycle.This paper presents a model-driven tool chain for the seL4 microkernel based on the open source High Assurance Modeling and Rapid engineering (HAMR) code generation framework for the Architecture and Analysis Definition Language (AADL). We describe how the semantics of AADL communication and threading can be realized in terms of the access primitives and strong spatial and temporal partitioning mechanisms provided by seL4. For AADL users, seL4 provides a high-assurance platform with formally verified enforcement of component boundaries and communication pathways. For seL4 users, AADL provides high-level abstractions for developing seL4 applications, along with an ecosystem of system engineering and analysis tools. We illustrate the framework by applying a model-based development environment for increasing resiliency against cyber attacks to an unmanned aircraft flight control system.

Design of an autonomous flight control system for imitation falcon flapping-wing aircraft

Bionic flapping-wing aircraft is a new type of aircraft with broad application prospects in the civil and military fields due to their low noise, good concealment, strong maneuverability, and high energy efficiency. The autonomous flying ability of bionic flapping-wing aircraft is the key to improving their flight efficiency. Although autonomous flight research on aircraft at home and abroad have made some achievements, few researchers have conducted corresponding studies on bionic flapping-wing aircraft. The unique driving structure of the bionic flapping-wing aircraft introduces great challenges to research on its autonomous flight control. In this paper, an autonomous flight control system is designed on the research platform of falcon flapping-wing aircraft. In consideration of the load problem of falcon flapping-wing aircraft, the hardware system is designed based on an STM32 microchip. A linear/nonlinear switching guidance algorithm is proposed considering the guidance accuracy and operation speed, due to the limited computing power of microcomputing platforms. Simulations prove that the proposed algorithm is more suitable for imitation falcon flapping-wing aircraft than linear guidance and nonlinear guidance algorithms. A cascade PID controller for roll angle and height is designed in consideration of the mechanism lag of falcon flapping-wing aircraft. By using this approach combined with ground station software for the imitation falcon flapping-wing aircraft, the task of autonomous fixed-height arc trajectory tracking based on imitation falcon flapping-wing aircraft is finally realized.

Flight Dynamics and Control of an eVTOL Concept Aircraft with a Propeller-Driven Rotor

The objective of this investigation is threefold. First, to assess the flight dynamics of an electric vertical take-off and landing (eVTOL) concept aircraft with a propeller-driven rotor. Second, to develop an automatic flight control system (AFCS) for this concept aircraft. Third, to verify the potential safety benefits of the concept aircraft by analyzing the autorotation performance following a total loss of power. The paper begins with an overview of the design of the aircraft and description of the simulation model, including a detailed discussion on the inflow model of the propellers that drive the main rotor. Next, the flight dynamics are assessed at hover and in forward flight. An AFCS based on dynamic inversion is developed to provide stability and desired response characteristics about the roll, pitch, yaw, and heave axes for speeds ranging from hover to 80 kt. Additionally, an RPM governor is implemented to hold the main rotor angular speed constant at its nominal value. Finally, simulations that make use of the AFCS are performed to analyze the autorotation performance following total loss of power.

Failures Mapping for Aircraft Electrical Actuation System Health Management

This paper presents the different types of failure that may occur in flight control electrical actuation systems. Within an aircraft, actuation systems are essential to deliver physical actions. Large actuators operate the landing gears and small actuators adjust passenger seats. As developing, aircraft systems have become more electrical to reduce the weight and complexity of hydraulic circuits, which could improve fuel efficiency and lower NOx emissions. Electrical Actuation (EA) are one of those newly electrified systems. It can be categorized into two types, Electro-Hydraulic Actuation (EHA) and Electro-Mechanical Actuation (EMA) systems. Emerging electric and hydrogen fuel aircraft will rely on all-electric actuation. While electrical actuation seems simpler than hydraulic at the systems level, the subsystems and components are more varied and complex. The aim of the overall project is to develop a highly representative Digital Twin (DT) for predictive maintenance of electrical flight control systems. A comprehensive understanding of actuation system failure characteristics is fundamental for effective design and maintenance. This research focuses on the flight control systems including the ailerons, rudders, flaps, spoilers, and related systems. The study uses the Cranfield University Boeing 737 as the basis to elaborate the different types of actuators in the flight control system. The Aircraft Maintenance Manual (AMM) provides a baseline for current maintenance practices, effort, and costs. Equivalent EHA and EMA to replace the 737 systems are evaluated. In this paper, the components and their failure characteristics are elaborated in a matrix. The approach to model these characteristics in DT for aircraft flight control system health management is discussed. This paper contributes to the design, operation and support of aircraft systems.

PFCS Four-redundant Sidestick Randomly Dynamically Grouping Vote Technology

For civil aircraft, the reliability of control device sensors in flight control system is very important for aircraft control and safe flight. Redundancy signal voting and monitoring technology can improve the availability and integrity of sensor signals in fly by wire primary flight control system of civil aircraft. In this paper, a simplified four-redundant signal voting and monitoring method is proposed which randomly and dynamically divides the four redundant signals into two groups for comparison. The safety analysis and simulation results reveal that this simplified method meets the safety requirements and has advantages in robustness and availability.

Research and modeling of force fighting equalisation for aircraft rudder’s triple active actuation system

AbstractThis paper presents a new approach to force fighting equalisation in a redundant active-active-active rudder actuation system that is used for the primary flight control system of a turboprop regional aircraft. The related coupled problem of force fighting scenario, and the hydraulic architecture of electronic-hydrostatic actuator (EHA) are analysed, the mathematical model of the EHA system is built. The virtual test bench is designed to evaluate the performance of the force fighting equalisation strategy. The proposed methodology is tested on an iron bird test rig. The physical experiment shows that the fighting force is minimised under all flight conditions, meets the low cost requirement and can be a very reliable system. The proposed methodology can be applied to other types of aircraft’ flight actuation systems.

Research on airworthiness test technology of radiation emission in civil aircraft flight control electronic system

It is the first time that domestic civil large aircraft has been developed, which lacks the technical experience of airborne system-level airworthiness qualification, and the research of radiation emission at home and abroad is mainly based on simulation evaluation, while the simulation results are used only as a reference in the airworthiness qualification process and cannot be used as evidence of conformity. And there is little airworthiness test experience on complex system-level. In this paper, taking civil aircraft flight control electronic system as an example, translate airworthiness compliance requirements into engineering requirements, analyze the complexity characteristics of civil aircraft flight control system, build flight control electronic system level radiation emission test system, and improve the system level airworthiness qualification test and optimization process, providing experience for the airworthiness qualification of civil aircraft complex system. The results show that the radiation emission of flight control electronic system is greatly affected by the system environment, and it is necessary to consider the influence of test setup layout and show the system compliance to the RTCA/DO-160G requirements.

Research on the Built-in Test Design of Civil Aircraft Flight Control System

Abstract Based on ARINC 624 for civil aircraft airborne maintenance system, the working modes and application forms of civil aircraft Flight Control System Built-in Test (BIT) design are given. The test principles and implementation methods of the civil aircraft Flight Control System Power-on BIT and Initiated BIT are analyzed in detail, and the overall functional architecture of the civil aircraft Flight Control System BIT is described. Taking the actuator as an example, the realization method of its return to service test is analyzed. Finally, the general characteristics of the BIT technology of the civil aircraft Flight Control System are summarized.

Sensor FDI and reconfiguration in B-747 aircraft flight control system

Sensor FDI and reconfiguration in B-747 aircraft flight control system

Sensor FDI and reconfiguration in B-747 aircraft flight control system

Sensor FDI and reconfiguration in B-747 aircraft flight control system

Design and Fabrication of a Testing Rig for UAV Using Pendulum Theory

The determination of an accurate value of a moment of inertia plays a vital role in designing decent mechanical parts as general such as a flight control system for aircraft. This why an accurate value for moment of inertia is needed. A test rig was designed and made form cardboard and then developed for wood. Experiments were carried out, to get to the final shape and product for the test rig, and it was manufactured with dimensions of 2.7x2.5 meters and with a holder dimension of 60x60 cm that bears up to 10 kg. Moreover, an electronic circuit has been used to measure the period of oscillations. The moment of inertia of a rectangular block of wood and a UAV is found. The moment of inertia was measured analytically and experimentally for the block of wood, and by comparing the values it founds that the error ratio from 1%to5% in X axis and -6% to 7% in Y axis. For the UAV the moment of inertia’s error ratio in X axis from 2% to 5% and in Y axis from 11% to 14%. It is noticed that the greater the additional weight, the greater the accuracy of the device.

Aircraft flight control system fault tolerance under structural and parametric uncertainties

The concept of an intelligent hybrid aircraft fault-tolerant flight control system operating under complete parametric and structural uncertainty is considered. Fault tolerance in the proposed system is ensured through the efficient integration of model-based and model-free health monitoring and reconfiguring methods.

Modeling multi-loop intelligent pilot control behavior for aircraft-pilot couplings analysis

Aircraft-pilot couplings (APCs) are one of the key factors that affect the flight safety of the modern aircraft. Among the several types of APCs, the nonlinear pilot induced oscillations caused by aircraft flight control system anomalies are extremely severe. In this paper, a multi-loop intelligent pilot model is presented for the analysis of the nonlinear pilot induced oscillations investigations. The multi-loop control tasks are introduced to define a typical multi-loop pilot modeling problem. The model is capable of describing the pilot's behavior during a multi-loop control task and analyzing the nonlinear pilot-induced oscillations when the flight control system is changed in different forms. Fuzzy control logic is designed to reflect the human pilot's behavior of making judgments. To be specific, the human pilot can change his/her control behavior adaptively when the aircraft flight control system falls into anomalies. Six cases of the abnormal flight control system are considered, and the control effects of the human pilot model are analyzed. The experimental results demonstrate that the human pilot can adjust the control strategy in different cases, which reflects the human pilot's adaptation to the changes of aircraft dynamics characteristics. Furthermore, it indicates that the human pilot model can obtain good control performance in tracking the command signal and can complete the task well facing the failures of the control system. Besides, the validity of the human pilot model is assessed by the scalogram-based PIO metric. The proposed pilot model can be applied in evaluating the aircraft loss-of-control events in the form of adverse aircraft-pilot couplings.

Gyroscope Fault Pattern Recognition Based on Wavelet Packet Decomposition and Fuzzy Clustering

Aiming at the problem that the sensor component’s inertial navigation gyro failure symptom is not obvious in a certain aircraft flight control system, this paper proposes a fault cluster recognition method based on fuzzy clustering. First, use wavelet packet decomposition to perform three-layer wavelet packet decomposition on the gyro output data to obtain the feature extraction of the gyro fault signal; then use the fuzzy clustering method to classify the extracted fault signal to achieve gyro fault pattern recognition in the sensor assembly the goal of.

Resilient event-triggered fault-tolerant control for networked control systems with randomly occurring nonlinearities and DoS attacks

This work studies the event-based fault-tolerant control issue of networked control systems with actuator saturation, resilient event-triggering, randomly occurring nonlinearities, and denial-of-service jamming attacks (DoS-JAs). Initially, we aim to design a resilient event-triggered (ET) communication scheme under the attacks, proposed by the known period of the jamming signal. The period values occur in uniform lower bounds for the jammer's sleeping time. Next, a closed-loop networked control system is constructed as a switched-control strategy subject to state-delay, in addition to actuator saturation, actuator faults, DoS jamming attack, parameter uncertainty and resilient ET control schemes. Based on the Lyapunov stability theory, piecewise property and Wirtinger-based integral inequality, a set of sufficient conditions are obtained to ensure that the resulting closed-loop switched system is exponentially stable against DoS jamming attacks and satisfies mixed and passivity performance index. Furthermore, the efficacy of the proposed method is demonstrated through simulated examples based on the two practical applications of satellite control systems and aircraft flight control systems.