Flight Control System Design Research Articles

Research on Triplex Redundant Flight Control System Based on M1394B Bus

In the modern aviation field, flight control systems’ reliability and safety are paramount. This paper presents a triplex redundant flight control system based on the M1394B bus and designs several key algorithms to enhance system performance. Firstly, a triplex redundant flight control system with a redundant bus structure is constructed based on the characteristics of the M1394B bus. Secondly, a periodic synchronization algorithm with automatic adjustment capabilities is designed to achieve periodic synchronization among the Vehicle Management Computers. An improved voting algorithm based on a sliding window is proposed to enhance the decision-making accuracy and reliability of the control commands output by the flight control system. Additionally, a system reconstruction algorithm is designed to promptly identify and isolate faults, enabling the recovery and reallocation of system resources. Finally, experiments validate the effectiveness of the synchronization algorithm, voting algorithm, and system reconstruction algorithm. The results indicate that the system can effectively address practical engineering challenges and significantly improve reliability and stability. This research provides an essential theoretical foundation and practical reference for the design of future flight control systems for unmanned aerial vehicles and aircraft, holding significant relevance to application.

A Neural-Metaheuristic Kalman Filter for Moving Microburst Wind Shear Identification

Microburst wind shears (MB) are powerful localized three dimensional (3D) columns of wind that occur when cooled air drops from the base of thunderstorms at high speeds. They eventually hit the ground and spread out in all directions. As such MBs are considered a major atmospheric hazard for aircrafts (ACs), especially in terminal flight phases. Though pilots train regularly to survive it, yet the most recommended practice within the aviation community is to avoid its encounter upon detection. Some modern aircrafts have predictive wind shear warning systems, but they have limited short range capability and do not provide quantitative data for engineering application. In this sense, accurate onboard detection and identification of MBs and its characteristics is of importance for flight safety, whose success can lead to design of automatic flight control systems (FCSs) that reduce the risk of aircraft crash landings and accidents. Even though there are some studies on FCS designs for MB encounter, research on MB identification is rare but ongoing. To this aim, the present study is among the firsts that focuses on online identification of multiple and moving MB parameters using onboard aircraft air data and inertial sensors. The identification task is initially performed using the aircraft six degrees of freedom (6DoF) equations of motion (EOM) integrated with a 3D MB model via the utility of nonlinear Kalman filtering (KF) algorithms. Subsequently, an enhanced neural metaheuristic Kalman filter (NMKF) is proposed that improves the estimation accuracy of the MB model parameters. The results demonstrate the efficacy of the proposed NMKF in comparison with previous studies.

Active Disturbance Rejection Flight Control and Simulation of Unmanned Quad Tilt Rotor eVTOL Based on Adaptive Neural Network

The unmanned quad tilt-rotor eVTOL (QTRV) is a variable-configuration aircraft that combines the features of vertical takeoff and landing (VTOL), hovering, and high-speed cruising, making its control system design particularly challenging. The flight dynamics of the QTRV differ significantly between the VTOL and cruise modes, and are further influenced by rotor tilt and external wind disturbances. Developing a unified, highly coupled nonlinear full-flight dynamics model facilitates flight control system design and simulation verification. To ensure stable tilt of the QTRV, a tilt corridor was established, along with the design of its tilt route and manipulation strategy. An adaptive neural network active disturbance rejection controller (ANN-ADRC) is proposed to ensure stable flight across all modes, reducing the control parameters and simplifying tuning while effectively estimating and compensating for unknown disturbances in real time. A hardware-in-the-loop (HIL) simulation system was designed for full-mode flight control simulation, and the results demonstrated the effectiveness of the proposed control method.

Full Envelope Flight Control System Design and Optimization for a Tilt-Wing Aircraft

Novel vertical take-off and landing advanced air mobility aircraft which are overactuated and transition between vertical and forward flight modes pose unique challenges for the design of safe and robust full‐envelope fly‐by‐wire flight control systems. This paper presents a methodology for designing and optimizing a control system architecture for a tilt-wing urban air mobility concept. It features the total energy control system algorithm, which is extended to be applicable to hover and transitioning flight and explicit model following inner loops. Control system parameters are optimized using a genetic algorithm optimization scheme, subject to constraints on closed-loop dynamic stability and control response characteristics. Control system performance is demonstrated by simulation of lateral, longitudinal, and directional maneuvering for hover, transition, and forward flight conditions, followed by simulation of departure and arrival transitions while tracking a prescribed flightpath and speed profile in calm and turbulent air. The results demonstrate the effectiveness of the proposed control system architecture and the demonstrated optimization methodology.

Flight control system design of UAV with wing incidence angle simultaneously and stochastically varied

PurposeThis study aims to simultaneously and stochastically maximize autonomous flight performance of a variable wing incidence angle having an unmanned aerial vehicle (UAV) and its flight control system (FCS) design.Design/methodology/approachA small UAV is produced in Iskenderun Technical University Drone Laboratory. Its wing incidence angle is able to change before UAV flight. FCS parameters and wing incidence angle are simultaneously and stochastically designed to maximize autonomous flight performance using an optimization method named simultaneous perturbation stochastic approximation. Obtained results are also benefitted during UAV flight simulations.FindingsApplying simultaneous and stochastic design approach for a UAV having passively morphing wing incidence angle and its flight control system, autonomous flight performance is maximized.Research limitations/implicationsPermission of the Directorate General of Civil Aviation in Turkish Republic is necessary for real-time flights.Practical implicationsSimultaneous stochastic variable wing incidence angle having UAV and its flight control system design approach is so useful for maximizing UAV autonomous flight performance.Social implicationsSimultaneous stochastic variable wing incidence angle having UAV and its flight control system design methodology succeeds confidence, excellent autonomous performance index and practical service interests of UAV users.Originality/valueCreating an innovative method to recover autonomous flight performance of a UAV and generating an innovative procedure carrying out simultaneous stochastic variable wing incidence angle having UAV and its flight control system design idea.

Octorotor flight control system design with stochastic optimal tuning, deep learning and differential morphing

Octorotor flight control system design with stochastic optimal tuning, deep learning and differential morphing

Fixed-wing UAV based on vortex lattice method modular technology research

The so-called modularity refers to dividing the system into several modules from top to bottom, layer by layer when solving a complex problem with various properties reflecting its internal characteristics. The main driving force for the demand for UAV modular technology comes from the requirements of UAV large-scale industrialization for UAV generalization, serialization, application scenario richness, and economy. The modular design of UAV is based on standardized software and hardware interfaces to carry out UAV aerodynamic shape module design, modular design of airframe structure, modular design of application load, module design of flight control system, module design of power system, etc.

Autonomous flight performance optimization of fixed-wing unmanned aerial vehicle with morphing wingtip

PurposeThe purpose of this paper is to improve autonomous flight performance of a fixed-wing unmanned aerial vehicle (UAV) via simultaneous morphing wingtip and control system design conducted with optimization, computational fluid dynamics (CFD) and machine learning approaches.Design/methodology/approachThe main wing of the UAV is redesigned with morphing wingtips capable of dihedral angle alteration by means of folding. Aircraft dynamic model is derived as equations depending only on wingtip dihedral angle via Nonlinear Least Squares regression machine learning algorithm. Data for the regression analyses are obtained by numerical (i.e. CFD) and analytical approaches. Simultaneous perturbation stochastic approximation (SPSA) is incorporated into the design process to determine the optimal wingtip dihedral angle and proportional-integral-derivative (PID) coefficients of the control system that maximizes autonomous flight performance. The performance is defined in terms of trajectory tracking quality parameters of rise time, settling time and overshoot. Obtained optimal design parameters are applied in flight simulations to test both longitudinal and lateral reference trajectory tracking.FindingsLongitudinal and lateral autonomous flight performances of the UAV are improved by redesigning the main wing with morphing wingtips and simultaneous estimation of PID coefficients and wingtip dihedral angle with SPSA optimization.Originality/valueThis paper originally discusses the simultaneous design of innovative morphing wingtip and UAV flight control system for autonomous flight performance improvement. The proposed simultaneous design idea is conducted with the SPSA optimization and a machine learning algorithm as a novel approach.

Design of flight control system of Quad Tilt Rotor UAV based on PID algorithm

This research focuses on the quadrotor tiltrotor unmanned aerial vehicle and considers various usage scenarios such as battlefield and transportation environments, as well as flight stability issues in complex meteorological environments. A PID control algorithm for rotor angle control of quadrotor tiltrotor unmanned aerial vehicles is designed, which is suitable for different usage scenarios and meteorological conditions.

Time-history performance optimization of flapping wing motion using a deep learning based prediction model

Flapping Wing Micro Aerial Vehicles (FWMAVs) have caused great concern in various fields because of their high efficiency and maneuverability. Flapping wing motion is a very important factor that affects the performance of the aircraft, and previous works have always focused on the time-averaged performance optimization. However, the time-history performance is equally important in the design of motion mechanism and flight control system. In this paper, a time-history performance optimization framework based on deep learning and multi-island genetic algorithm is presented, which is designed in order to obtain the optimal two-dimensional flapping wing motion. Firstly, the training dataset for deep learning neural network is constructed based on a validated computational fluid dynamics method. The aerodynamic surrogate model for flapping wing is obtained after the convergence of training. The surrogate model is tested and proved to be able to accurately and quickly predict the time-history curves of lift, thrust and moment. Secondly, the optimization framework is used to optimize the flapping wing motion in two specific cases, in which the optimized propulsive efficiencies have been improved by over 40% compared with the baselines. Thirdly, a dimensionless parameter Cvariation is proposed to describe the variation of the time-history characteristics, and it is found that Cvariation of lift varies significantly even under close time-averaged performances. Considering the importance of time-history performance in practical applications, the optimization that integrates the propulsion efficiency as well as Cvariation is carried out. The final optimal flapping wing motion balances good time-averaged and time-history performance.

Effect of Hindwings on the Aerodynamics and Passive Dynamic Stability of a Hovering Hawkmoth.

Insects are able to fly stably in the complex environment of the various gusts that occur in nature. In addition, many insects suffer wing damage in their lives, but many species of insects are capable of flying without their hindwings. Here, we evaluated the effect of hindwings on aerodynamics using a Navier-Stokes-based numerical model, and then the passive dynamic stability was evaluated by coupling the equation of motion in three degrees of freedom with the aerodynamic forces estimated by the CFD solver under large and small perturbation conditions. In terms of aerodynamic effects, the presence of the hindwings slightly reduces the efficiency for lift generation but enhances the partial LEV circulation and increases the downwash around the wing root. In terms of thrust, increasing the wing area around the hindwing region increases the thrust, and the relationship is almost proportional at the cycle-averaged value. The passive dynamic stability was not clearly affected by the presence of the hindwings, but the stability was slightly improved depending on the perturbation direction. These results may be useful for the integrated design of wing geometry and flight control systems in the development of flapping-winged micro air vehicles.

Safety Design of Uncontained Engine Rotor Failure for Civil Aircraft Primary Flight Control System

The safety design of uncontained engine rotor failure for civil aircraft primary flight control systems is more difficult than other airborne systems. This paper presents a safety design method that establishes a two-stage collision model inspection mechanism and introduces an automatic analysis algorithm in the process of comprehensive impact analysis of the cascade system. The method applies to the detailed design stage of civil aircraft systems. It can reduce the difficulty of the safety analysis process and improve the accuracy of the analysis results. The verification of a civil aircraft primary flight control system design shows that after using the safety design method, the time cost of the analysis process is significantly reduced, and the analysis results are more accurate, thereby reducing the difficulty of design changes.

Promoting the Maneuverability and Fault-Tolerant Control Capabilities of Dual-System/Hybrid VTOL UAVs

This paper presents an active fault-tolerant flight control system (FCS) design for the dual-system/hybrid VTOL UAV configuration that maximally exploits its inherent over-actuation abilities to provide higher levels of fault-tolerance and reliability compared to that of the other VTOL UAVs configurations up to this point. The significance of this study is to convert the main drawback of having the vertical rotors as dead weights during the cruise to a key advantage where all the UAV's controls are kept active during all the flight phases raising the UAV's fault-tolerance and maneuverability abilities. The FCS proposed elaborates on a new architecture for the hierarchical automatic control loops using the dynamic inversion control to design the trajectory tracking virtual commands and employing optimal dynamic control allocation to optimally resolve the controls redundancy. Regarding fault-tolerance, the presented FCS handles simultaneous failures and jamming of all the control surfaces during flight where the control commands to the healthy controls (vertical rotors) were automatically adapted such that the trimming and trajectory tracking were successfully maintained till the mission end. Additionally, this paper addresses for the first time the employment of the controls redundancy to enhance the VTOL UAV's maneuverability in fault-free cases, where we present a study of reducing the minimum turn radius of the UAV when the vertical rotors are employed with the control surfaces during the maneuver. A reduction of 38% in the coordinated steady-level minimum turn radius turn at 35 m/sec flight speed was achieved.

Integrated Flight Control System Characterization Approach for Civil High-Speed Vehicles in Conceptual Design

Recent studies have revealed that control surface deflection can cause a reduction in the aerodynamic efficiency of a hypersonic aircraft of up to 30%. In fact, the characterization of the Flight Control System is essential for the estimation of the consistent aerodynamic characteristics of the vehicle in different phases, considering the contribution of control surfaces to stability and trim. In terms of the sizing process, traditional methodologies have been demonstrated to be no longer applicable to estimations of the actuation power required for the control surfaces of a high-speed aircraft, due to their peculiar working conditions and to the characteristics of the flow to which they are exposed. In turn, numerical simulation approaches based on computational fluid dynamics or panel methods may require considerable time resources, which do not fit with the needs of the quick and reliable estimates that are typical of the early design phases. Therefore, this paper is aimed at describing a methodology to show how to anticipate the Flight Control System design for high-speed vehicles at the conceptual design stage, properly considering the interactions at vehicle level and predicting the behavior of the system throughout an entire mission. It is also a core part of the work to provide designers with an example of how neglecting the effect of trim drag can be detrimental to a reliable estimation of overall aircraft performance. The analysis, mainly focused on the longitudinal plane of the vehicle, is presented step-by-step on a specific case study, namely the STRATOFLY MR3 vehicle, a Mach 8 waverider concept for civil antipodal flights. The application of the methodology, conceived as an initial step towards an iterative Flight Control System design process, also shows that the most power-demanding phases are take-off, low supersonic acceleration, and approach, where peaks of over 130 kW are reached, while an average of 20 kW is sufficient to support deflections in a hypersonic cruise.

Comparison of Linear Flexible Aircraft Model Structures on Large Flexible Tiltrotor Aircraft

Structural modes for large aircraft occur at low frequencies and must be accounted for in the flight dynamics modeling and control system design process. An analysis is performed on various linear representations of flexible aircraft with an application to the lateral/directional flexible dynamic response of the notional Large Civil Tiltrotor (LCTR2) in hover. The goal of the work is to compare the treatment of the coupling between the rigid-body and structural states within various model structures and to develop conversions between the various model forms. The analysis shows that mean-axis and other simplified analytical representations of flexible aircraft, originally developed for fixed-wing aircraft, are also able to correctly capture the dynamic response of a tiltrotor. First, a linear model is obtained from a multibody simulation using numerical perturbation methods. This is compared with a mean-axis model, where structural dynamics are appended onto rigid-body dynamics, as would be obtained if the rigid-body aircraft response were the starting point in an analytical development of the structural coupling. Comparisons are also given with a model that would be obtained from system identification using flight-test data. Key stability and control derivatives are compared to highlight similarities and differences between the various models. The results from the analysis show the multibody model treats the structural coupling in a significantly different way than an analytical model buildup. For example, the structural coupling to roll rate response varies up to two orders of magnitude between the models, yet the overall response is identical. This work shows analysis of the structural/rigid-body coupling developed for analytical models is also valid for models developed from a multibody analysis. Lastly, structural flexibility will be shown to alter the characteristics of the lateral hovering cubic of the LCTR2 by increasing damping of an unstable oscillatory mode.

Simultaneous UAV having actively sweep angle morphing wing and flight control system design

PurposeThe purpose of this paper is to improve autonomous flight performance of an unmanned aerial vehicle (UAV) having actively sweep angle morphing wing using simultaneous UAV and flight control system (FCS) design.Design/methodology/approachAn UAV is remanufactured in the ISTE Unmanned Aerial Vehicle Laboratory. Its wing sweep angle can vary actively during flight. FCS parameters and wing sweep angle are simultaneously designed to optimize autonomous flight performance index using a stochastic optimization method called as simultaneous perturbation stochastic approximation (SPSA). Results obtained are applied for flight simulations.FindingsUsing simultaneous design process of an UAV having actively sweep angle morphing wing and FCS design, autonomous flight performance index is maximized.Research limitations/implicationsAuthorization of Directorate General of Civil Aviation in Turkey is crucial for real-time UAV flights.Practical implicationsSimultaneous UAV having actively sweep angle morphing wing and FCS design process is so beneficial for recovering UAV autonomous flight performance index.Social implicationsSimultaneous UAV having actively sweep angle morphing wing and FCS design process achieves confidence, high autonomous performance index and simple service demands of UAV operators.Originality/valueComposing a novel approach to improve autonomous flight performance index (e.g. less settling and rise time, less overshoot meanwhile trajectory tracking) of an UAV and creating an original procedure carrying out simultaneous UAV having actively sweep angle morphing wing and FCS design idea.

Robust flight control system design of a fixed wing UAV using optimal dynamic programming

Robust flight control system design of a fixed wing UAV using optimal dynamic programming

Design of Non-Conventional Flight Control Systems for Bioinspired Micro Air Vehicles

This research focuses on the development of two bioinspired micro air vehicle (MAV) prototypes, based on morphing wings and wing grid wingtip devices. The morphing wings MAV tries to adapt the aerodynamics of the vehicle to each phase of flight by modifying the vehicle geometry, while the wing grid MAV aims to minimize the aerodynamic and weight penalty of these vehicles. This work focuses on the design methodology of the flight control system of these MAVs. A preliminary theoretical conceptual design was used to verify the requirements, wind tunnel tests were performed to determine aerodynamic characteristics, and suitable materials were selected. The hardware and software configuration designed for the control system, which fulfills the objective of adaptive and optimal control in the wingtip-based prototype of the wing grid, is described. Finally, the results of the flight control on the prototype MAVs are analyzed.

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.

Linear Quadratic Regulation Method for a Roll Yaw Coupled Supersonic Flight Vehicle

In this literature, a linear quadratic regulation (LQR) method with controller reconfiguration and state observer is proposed for analyses and designs of a supersonic roll-yaw coupled flight control system. The flight control system of some specially shaped airframe can be decomposed into a Pitch Control System and a Roll-Yaw Coupled Control System. It can be designed separately, no need for three loops to be designed together. The design process is relatively simple, which is conducive to the design of flight control systems in large airspace. The proposed method for the considered system will give the good tracking characteristic at low frequencies and robustness at middle frequencies; simultaneously. All state variables are measurable and found controllers are all realizable either in analog or digital hardware.