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Öğe A review of control strategies used for morphing aircraft applications(Elsevier Science Inc, 2024) Parancheerivilakkathil, Muhammed S.; Pilakkadan, Jafar S.; Ajaj, Rafic M.; Amoozgar, Mohammadreza; Asadi, Davood; Zweiri, Yahya; Friswell, Michael I.This paper reviews the various control algorithms and strategies used for fixed -wing morphing aircraft applications. It is evident from the literature that the development of control algorithms for morphing aircraft technologies focused on three main areas. The first area is related to precise control of the shape of morphing concepts for various flight conditions. The second area is mainly related to the flight dynamics, stability, and control aspects of morphing aircraft. The third area deals mainly with aeroelastic control using morphing concepts either for load alleviation purposes and/or to control the instability boundaries. The design of controllers for morphing aircraft/wings is very challenging due to the large changes that can occur in the structural, aerodynamic, and inertial characteristics. In addition, the type of actuation system and actuation rate/ speed can have a significant effect on the design of such controllers. The aerospace community is in strong need of such a critical review especially as morphing aircraft technologies move from fundamental research at a low Technology Readiness Level (TRL) to real -life applications. This critical review aims to identify research gaps and propose future directions. In this paper, research activities/papers are categorized according to the control strategy used. This ranges from simple Proportional Integral Derivative (PID) controllers at one end to complex robust adaptive controllers and deep learning algorithms at the other end. This includes analytical, computational, and experimental studies. In addition, the various dynamic models used and their fidelities are highlighted and discussed. (c) 2023 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).Öğe Active fault-tolerant control of quadrotor UAVs with nonlinear observer-based sliding mode control validated through hardware in the loop experiments(Pergamon-Elsevier Science Ltd, 2023) Ahmadi, Karim; Asadi, Davood; Merheb, Abdelrazzak; Yaser Nabavi-Chashmi, Seyed-; Tutsoy, ÖnderMultirotor unmanned aerial vehicles (UAV) are highly prone to motor faults, which can arise from defective motors or damaged propellers. Motor faults severely change the multirotor UAV's dynamics and therefore endanger flight safety and reliability since the controller loses its efficiency. To cope with such crucial problems, a fault-tolerant controller is proposed in this paper for full control of a quadrotor UAV with motor faults. The proposed fault-tolerant approach consists of the nonlinear observer technique and the Sliding Mode Control (SMC). The designed novel nonlinear observer predicts the effects of motor faults on quadrotor dynamics and it is augmented with an SMC to create a fault-tolerant controller. In addition, the nonlinear observer enhances the robustness of the SMC against the uncertainties and disturbances acting on the quadrotor during flight. Any actuator fault will be treated as a disturbance detected by the nonlinear observer and will be attenuated directly by the proposed SMC. The disturbance attenuation capability achieved by the nonlinear observer decreases the amount of control action expected from the SMC, which results in advanced robustness without sacrificing the nominal control performance. The performance of the proposed nonlinear observer SMC (NOSMC) is demonstrated through simulations and testbed experiments. The results show that the proposed fault-tolerant controller effectively recovers the full control of the quadrotor with motor faults up to 40% while tracking the predefined trajectory and rotation angles as desired.Öğe Active flutter control of thin walled wing-engine system using piezoelectric actuators(Elsevier France-Editions Scientifiques Medicales Elsevier, 2020) Asadi, Davood; Farsadi, TourajIn the present study, control of a Thin Walled Beam (TWB) wing-engine system is examined applying piezoelectric actuators to enhance the performance of aeroelastic response. The composite piezoelectric governing equations of motion including the structure and electric effects are derived applying Hamilton's principle. Piezoelectric composite plate equations are added to the composite host wing-engine governing system of equations. The incompressible aerodynamic model based on Wagner's function is applied and the Ritz based solution methodology is employed. As a passive control approach, the effects of piezoelectric fiber angles are studied on the time domain response of the high-aspect-ratio wing-engine system. The linear quadratic Gaussian (LQG) control algorithm is applied as a closed-loop active control strategy to enhance the flutter response characteristics of the composite wing-engine system. Numerical results firstly, demonstrate the effectiveness of the active control strategy based on piezocomposite actuator on suppressing the flutter response of the composite wing-engine system and secondly, prove the effect of piezocomposite actuator location and fiber angle orientation on the closed-loop control performance. (C) 2020 Elsevier Masson SAS. All rights reserved.Öğe Actuator Fault Detection, Identification, and Control of a Multirotor Air Vehicle Using Residual Generation and Parameter Estimation Approaches(Springer, 2024) Asadi, DavoodEffective fault detection and identification (FDI) and fault-tolerant control for nonlinear, unstable, and underactuated systems like quadrotor is a challenging and critical process. This paper introduces a novel two-stage structure of an FDI approach integrated with an adaptive sliding mode controller for fault-tolerant control of a quadrotor with partial actuator fault. The FDI algorithm applies the parity space concept to generate a residual signal based on the system's states and the inputs. The residual signal is examined by the exponential forgetting factor recursive least square method to detect and identify the partial fault of the actuator. The cascade controller includes an adaptive SMC algorithm in the inner loop and a PID controller in the outer loop. Real-time testbed experiments and Monte-Carlo simulation are applied in different actuator fault scenarios to determine the FDI algorithm's performance metrics and demonstrate the effectiveness of the proposed algorithm. in maintaining full controllability of the quadrotor in presence of partial actuator fault.Öğe Automatic Landing Control of a Multi-Rotor UAV Using a Monocular Camera(Springer, 2022) Nabavi, Yaser; Asadi, Davood; Ahmadi, KarimThe reliability of autonomous landing of the UAVs in an unknown or unprepared environment can be improved by the application of image-based sensors. This paper investigates the landing control of a multirotor UAV by controlling the optical flow and estimation of vertical distance supported by a low-cost monocular camera. Landing control and vertical distance estimation using just a camera as the sensor, makes the proposed approach well-suited for emergency scenarios in GPS denied environment. To develop the optical flow-based controller strategy, an appropriate nonlinear model is proposed by combining the optical flow equations and the kinematics of vertical landing. In the control loop of the multirotor landing, an estimation of the vertical distance is required, which is provided by the application of the developed model and the optical flow derived from camera images. RLS algorithm and the EKF have been applied to estimate the vertical distance. The controller output is determined by using the NDI algorithm, the augmented state-space form of the equations, and the estimated states based on optical flow. An experimental setup is developed for the tasks of optical flow extraction, vertical distance estimation, and control. Additionally, the developed estimation and controller strategy are applied to the nonlinear dynamics of a quadrotor to demonstrate the applicability of the proposed models and algorithms for landing control. According to the results, the proposed optical flow-based control strategy can support a smooth landing for the multirotor UAV while its performance is dependent on the quality of estimation. There is a steady-state error in tracking the optical flow due to the estimation error of the vertical distance. The EKF-based algorithm has better performance in terms of estimation accuracy respecting the RLS, and therefore supports a better landing performance.Öğe Fault-tolerant Trajectory Tracking Control of a Quadcopter in Presence of a Motor Fault(Springer, 2022) Asadi, Davood; Ahmadi, Karim; Nabavi, Seyed YaserAs a part of emergency landing architecture for multi-rotor, a fault-tolerant trajectory tracking control strategy is proposed in this paper to control a quadcopter in case of a partial motor fault. The introduction of fault-tolerant strategy includes a lightweight fault detection and identification algorithm and a three-loop tracking controller. The lightweight fault detection and identification algorithm identifies the fault based on the controller outputs and the angular rates calculated by a discrete extended Kalman filter. The three-loop controller comprises a cascade structure of a discrete nonlinear adaptive algorithm in the inner-loop and a PID algorithm in the outer-loops of the controller structure. To have more realistic simulations, the gyroscopic effects of rotors and the airframe drag terms are considered in modeling as the model uncertainty. The simulation results demonstrate that the proposed fault-tolerant controller can effectively control the quadcopter in presence of partial motor fault, model uncertainties, and sensor noises. The results also demonstrate the effect of fault detection time delay on the overall control performance.Öğe Flutter improvement of a thin walled wing-engine system by applying curvilinear fiber path(Elsevier France-Editions Scientifiques Medicales Elsevier, 2019) Farsadi, Touraj; Asadi, Davood; Kurtaran, HasanIn the present study, the aeroelastic behavior of a wing-engine system modeled as composite Thin Walled Beam (TWB) with curvilinear fiber path is investigated. The variable stiffness is acquired by constructing laminates of TWB with curvilinear fibers having prescribed paths. In order to account the effect of chordwise and spanwise locations, mass, and thrust force of engine on the aeroelastic characteristics of TWB, the novel governing equations of motion are obtained using Hamilton's variational principle. The paper aims to exploit desirable fiber paths with improved aeroelastic properties for different wing-engine configuration. Ritz based solution methodology is employed to solve the equations with coupled incompressible unsteady aerodynamic model based on Wagner's function. Numerical simulation results which conform to previously published literatures are presented for validation purposes. Although different curvilinear fiber paths can be introduced to enhance flutter instabilities for each wing-engine configurations, there exists an ideal placement of engine on the wing considering only the engine mass, and the engine mass and thrust force, simultaneously. A comprehensive insight is provided over the effect of parameters such as the lamination fiber path and the effect of engine positions with different mass and thrust values on the flutter speed and frequency. (C) 2019 Elsevier Masson SAS. All rights reserved.Öğe Flutter Optimization of a Wing-Engine System with Passive and Active Control Approaches(Amer Inst Aeronautics Astronautics, 2021) Asadi, Davood; Farsadi, Touraj; Kayran, AltanIn the present study, the flutter performance of a composite thin-walled beam wing-engine system is optimized by implementing two different control approaches: 1) passive open-loop and 2) active closed-loop control. Sequential quadratic programming and genetic algorithm methods are applied in the optimization process. In the passive control method, variable stiffness is acquired by constructing laminates of thin-walled beam with curvilinear fibers having prescribed paths. The goal is to exploit the desirable fiber paths with improved flutter performance to determine an optimized wing-engine aeroelastic configuration. In the active control strategy, piezo-composite actuators and the linear quadratic Gaussian algorithm are used to improve the flutter characteristics. A novel optimization strategy based on the total energy of the aeroelastic system is introduced and applied in both passive and active control strategies. The minimum total aeroelastic energy is an indication of ideal optimization variables, which leads to optimum flutter performance. The governing equations are formulated based on Librescu's thin-walled beam theory and Hamilton's principle. An unsteady aerodynamic model based on incompressible indicial aerodynamics is applied. The governing equations of motion are solved using a Ritz-based solution methodology. Numerical results demonstrate a 16 and 46% improvement in the flutter speed of the wing-engine system using the proposed passive and active control approaches, respectively. The presented results provide valuable information concerning the design of advanced lightweight and high-aspect-ratio aircraft wings with mounted engines in terms of favorable aeroelastic performance characteristics.Öğe Fundamental frequency optimization of variable stiffness composite skew plates(Springer Wien, 2021) Farsadi, Touraj; Asadi, Davood; Kurtaran, HasanIn this study, natural frequencies and vibrational mode shapes of variable stiffness composite skewed plates are optimized applying a genetic algorithm. The variable stiffness behavior is obtained by altering the fiber angles continuously according to two selected curvilinear fiber path functions in the composite laminates. Fundamental frequency and related mode shapes of the plates are optimized for two different fiber path functions using the structural model obtained based on the virtual work principle. A three-layer composite skewed plate with four types of boundary conditions and different plate geometries is considered as case study in this research. Diverse sweptback angles as well as different aspect ratios are considered as various plate geometries. The present study aims to calculate the best fiber path with maximized fundamental frequency or in-plane strengths for a composite skewed plate. The generalized differential quadrature method of solution is employed to solve the governing equations of motion. Moreover, the linear kinematic strain assumptions are used, and the first-order shear deformation theory is employed to generalize the formulation for the case of moderately thick plates including transverse shear effects. Numerical results demonstrate the effect of the fiber angles, boundary conditions, and diverse geometries on the natural frequencies of the composite plate. The optimal fiber angles of each layer are presented for the above cases in free vibration analysis. It is verified that the application of optimized curvilinear fibers instead of the traditional straight fibers introduces a higher degree of flexibility, which can be used to adjust frequencies and mode shapes.Öğe Image-based UAV position and velocity estimation using a monocular camera(Pergamon-Elsevier Science Ltd, 2023) Nabavi-Chashmi, Seyed-Yaser; Asadi, Davood; Ahmadi, KarimAutonomous landing of aerial vehicles is challenging, especially in emergency flight scenarios in which precise information about the vehicle and the environment is required for near-to-ground maneuvers. In this paper, the optic-flow concept based on feature detection is applied to estimate the vertical distance and the velocity vector of a multirotor UAV (MUAV) for landing. The UAV kinematics, the optical flow equations, and the detected feature states, provided by a low-cost monocular camera, are combined to develop a novel appropriate model for estimation. The proposed algorithm applies the variation of detected features, the angular velocities, as well as the Euler angles, measured by the Inertial Measurement Unit (IMU), to estimate the vertical distance of the UAV to the ground, the MUAV velocity vector, and also to predict the future features position. Extended Kalman filter (EKF) is applied as the estimation method on the coupled optic-flow and kinematic equations. The accuracy of state estimation is enhanced by the idea of multiple-feature tracking. The 6-DOF simulations, laboratory experiments, and comparison of results demonstrate the capability of height and velocity estimation of a MUAV in the landing phase of flight by just applying the low-cost camera information. Monte Carlo simulations have been performed to study the effect of IMU acceleration, and angular velocity measurement noises as well as the number of the detected features on the success probability of the estimation process. The results reveal that increasing the number of detected features, i.e tracking multiple features, increases the estimation accuracy, however, it mainly improves the success probability, which is a more important factor in practical scenarios.Öğe INNOVATIVE SYNERGIES IN AIRCRAFT PROPULSION: THE CONCEPT OF HYBRID POWER SYSTEMS WITH CONTRA-ROTATING PROPELLERS(American Society of Mechanical Engineers (ASME), 2024) Hazeri, Majid; Moradkhani, Mohsen; Jafari, Javad Rashid; Asadi, DavoodIn an era characterized by escalating emphasis on fuel economy and the mitigation of greenhouse gas emissions within the aerospace industry, this paper presents an innovative paradigm including the hybrid electric engine with contra-rotating propellers. This article unveils a pioneering technological achievement, exemplified by our patented invention registered under the identifier IB/2021/060538, which received a gold medal at the ICAN 2022 International Invention competition in Toronto, Canada, represents a noteworthy advancement in the domain of hybrid engine technology. It is imperative to acknowledge that the concept is currently in the conceptual design phase, necessitating further refinement to attain its maximum potential. The engine, characterized as a contra-rotating propeller system, engenders an efficiency gain ranging from 6% to 16% relative to single-fuel engines, with one internal combustion engine providing half of the required power and the electric motor complementing the remaining share. This innovative system comprises two distinct configurations: a system with two electric motors and one fuel engine in which one of the electric engines is used as a backup engine. In case of user preference or fuel engine failure, the backup electric is engaged in place of the fuel engine. This paradigm-shifting innovation effectively changes the conventional internal combustion engine into a multi-engine anti-torque system, facilitating augmented thrust generation while simultaneously reducing fuel consumption by an impressive margin of 40% to 60% when compared with conventional engine models. Beyond its commendable fuel efficiency, the hybrid engine is characterized by a satisfactory level of reliability. This is related to the inclusion of a backup electric motor. In addition to the internal combustion engine, supporting the system with the ability to manage system failures and maintain power output even under emergency circumstances. Notably, the fundamental concept of the contra-rotating propeller system is not entirely novel, however, our innovative approach harmoniously synchronizes two electric motors, thereby containing the advantages inherent in the contra-rotating system with the reliability attributed to electric propulsion. Copyright © 2024 by ASME.Öğe INNOVATIVE SYNERGIES IN AIRCRAFT PROPULSION: THE CONCEPT OF HYBRID POWER SYSTEMS WITH CONTRA-ROTATING PROPELLERS(Amer Soc Mechanical Engineers, 2024) Hazeri, Majid; Moradkhani, Mohsen; Jafari, Javad Rashid; Asadi, DavoodIn an era characterized by escalating emphasis on fuel economy and the mitigation of greenhouse gas emissions within the aerospace industry, this paper presents an innovative paradigm including the hybrid electric engine with contra-rotating propellers. This article unveils a pioneering technological achievement, exemplified by our patented invention registered under the identifier IB/2021/060538, which received a gold medal at the ICAN 2022 International Invention competition in Toronto, Canada, represents a noteworthy advancement in the domain of hybrid engine technology. It is imperative to acknowledge that the concept is currently in the conceptual design phase, necessitating further refinement to attain its maximum potential. The engine, characterized as a contrarotating propeller system, engenders an efficiency gain ranging from 6% to 16% relative to single-fuel engines, with one internal combustion engine providing half of the required power and the electric motor complementing the remaining share. This innovative system comprises two distinct configurations: a system with two electric motors and one fuel engine in which one of the electric engines is used as a backup engine. In case of user preference or fuel engine failure, the backup electric is engaged in place of the fuel engine. This paradigm-shifting innovation effectively changes the conventional internal combustion engine into a multi-engine anti-torque system, facilitating augmented thrust generation while simultaneously reducing fuel consumption by an impressive margin of 40% to 60% when compared with conventional engine models. Beyond its commendable fuel efficiency, the hybrid engine is characterized by a satisfactory level of reliability. This is related to the inclusion of a backup electric motor. In addition to the internal combustion engine, supporting the system with the ability to manage system failures and maintain power output even under emergency circumstances. Notably, the fundamental concept of the contra-rotating propeller system is not entirely novel, however, our innovative approach harmoniously synchronizes two electric motors, thereby containing the advantages inherent in the contra-rotating system with the reliability attributed to electric propulsion.Öğe Minimum Distance and Minimum Time Optimal Path Planning With Bioinspired Machine Learning Algorithms for Faulty Unmanned Air Vehicles(IEEE-Inst Electrical Electronics Engineers Inc, 2024) Tutsoy, Önder; Ahmadi, Karim; Asadi, Davood; Nabavi-Chashmi, Seyed Yaser; Iqbal, JamshedUnmanned air vehicles operate in highly dynamic and unknown environments where they can encounter unexpected and unseen failures. In the presence of emergencies, autonomous unmanned air vehicles should be able to land at a minimum distance or minimum time. Impaired unmanned air vehicles define actuator failures and this impairment changes their unstable and uncertain dynamics; henceforth, path planning algorithms must be adaptive and model-free. In addition, path planning optimization problems must consider the unavoidable actuator saturations, kinematic and dynamic constraints for successful real-time applications. Therefore, this paper develops 3D path planning algorithms for quadrotors with parametric uncertainties and various constraints. In this respect, this paper constructs a multi-dimensional particle swarm optimization and a multi-dimensional genetic algorithm to plan paths for translational, rotational, and Euler angles and generates the corresponding control signals. The algorithms are assessed and compared both in the simulation and experimental environments. Results show that the multi-dimensional genetic algorithm produces shorter minimum distance and minimum time paths under the constraints. The real-time experiments prove that the quadrotor exactly follows the produced path utilizing the available maximum rotor speeds.Öğe Model-based Fault Detection and Identification of a Quadrotor with Rotor Fault(Springer, 2022) Asadi, DavoodFault detection and identification (FDI) is a challenging and critical process when dealing with nonlinear, unstable, and underactuated systems such as multirotor. This article presents a novel two-stage structure for a fault-tolerant FDI approach for a quadrotor with an actuator fault. The FDI algorithm generates residual signals for fault detection using a model-based approach based on the parity space. The basic idea behind this approach is to leverage measurement coherence by generating residuals via linear combinations of measurement outputs and control inputs over a finite window. The parity vector is generated using the states of the faulty system, which have been filtered using an extended Kalman filter, the inputs, and the healthy quadrotor model. To detect and identify the actuator's partial fault, the residual signal is examined using the exponential forgetting factor recursive least square method. Real-time testbed experiments are used to determine the FDI algorithm's performance and to demonstrate the proposed algorithm's effectiveness in identifying a quadrotor's rotor fault.Öğe Modified adaptive discrete-time incremental nonlinear dynamic inversion control for quad-rotors in the presence of motor faults(Academic Press Ltd- Elsevier Science Ltd, 2023) Ahmadi, Karim; Asadi, Davood; Nabavi-Chashmi, Seyed-Yaser; Tutsoy, ÖnderUnmanned air vehicles are intrinsically non-linear, unstable, uncertain, and prone to a variety of faults, most commonly the motor faults. The main objective of this paper is to develop a faulttolerant control algorithm for the quadrotors with the motor faults. Accordingly, a novel adaptive modified incremental nonlinear dynamic inversion (MINDI) control is proposed to stabilize and control the quad-rotor with partial motor faults. The controller consists of a MINDI controller augmented with a discrete-time nonlinear adaptive algorithm. Since the incremental nonlinear dynamic inversion (INDI) algorithm is essentially based on the sensor measurements, it necessitates the angular rates differentiation and therefore amplifies the high-frequency noises produced by the gyroscopes. The application of derivative filters causes unavoidable internal state delays in the INDI structure. Henceforth, the performance of the controller developed for the unstable and uncertain quadrotors degrades considerably. To address this drawback, this paper proposes the MINDI controller which basically derives the angular accelerations from the angular moment estimations. Furthermore, to increase the robustness of the MINDI against motor faults, a discrete-time adaptive controller has been incorporated. The performance of the proposed controllers is verified both through the nonlinear simulations and testbed experiments. The results are compared with a recent efficient algorithm, which had been implemented on a quad-rotor model.Öğe Multi-Objective Cooperated Path Planning of Multiple Unmanned Aerial Vehicles Based on Revisit Time(Amer Inst Aeronautics Astronautics, 2021) Haghighi, Hassan; Asadi, Davood; Delahaye, DanielThis paper investigates multi-objective optimization of coordinated patrolling flight of multiple unmanned aerial vehicles in the vicinity of terrain, while respecting their performance parameters. A new efficient modified A-star (A*) algorithm with a novel defined criterion known as individual revisit time cell value is introduced and extended to the whole area of the three-dimensional mountainous environment. As a contribution to solving tradeoffs in the optimization problem, revisit time is conjugated with other contrary costs effective in flight planning through Pareto analysis. By introducing the revisit time and applying a specific setup to mitigate computational complexity, the proposed algorithm efficiently revisits the desired zones, which are more important to be revisited during the patrolling mission. The results of the introduced modified A* algorithm are compared in various scenarios with two different algorithms: a complete and optimal algorithm known as Dijkstra, and an evolutionary algorithm known as the genetic algorithm. Simulation results demonstrate that the proposed algorithm generates faster and more efficient trajectories in complex multi-agent scenarios due to the introduced cell selection method and dynamic-based simplifications applied in this research.Öğe Nonlinear flutter response of a composite plate applying curvilinear fiber paths(Springer, 2020) Farsadi, Touraj; Asadi, Davood; Kurtaran, HasanIn the present study, nonlinear flutter and post-flutter behavior of a variable stiffness composite wing-like plate is investigated. The variable stiffness is obtained by varying fiber angles continuously according to a selected curvilinear fiber path function in the composite laminates. Flutter speed, limit cycle oscillations and bifurcation diagrams of the composite plate are explored for three different fiber path functions using the nonlinear structural model obtained based on the virtual work principle. The paper aims to exploit the ideal fiber paths with enhanced aeroelastic flutter and post-flutter properties for a composite plate in supersonic flow speed. First-order linear piston theory is applied to model the aerodynamics, and generalized differential quadrature is employed to solve the governing equations. Von Karman nonlinear strain theory is used to account for the geometric nonlinearities, and first-order shear deformation theory is employed to consider the transverse shear effects in the structural model. Time integration of the equation of motion is carried out using the Newmark average acceleration method. Different curvilinear fiber paths are introduced to enhance flutter instabilities and post-flutter behavior of the composite plate. Results demonstrate that the fiber orientation has a significant effect on the dynamic behavior of the plate and the asymmetric properties as well as the behavior of the limit cycle oscillation. © 2019, Springer-Verlag GmbH Austria, part of Springer Nature.Öğe Nonlinear robust adaptive control of an airplane with structural damage(Sage Publications Ltd, 2020) Asadi, Davood; Ahmadi, KarimThis article investigates the design of a novel nonlinear robust adaptive control architecture to stabilize and control an airplane in the presence of left-wing damage. Damage effect is modeled by considering the sudden mass and inertia changes, center of gravity, and aerodynamic variations. The novel nonlinear control algorithm applies a state predictor as well as the error between the real damaged dynamics and a virtual model based on the nominal aircraft dynamics in the control loop of the adaptive strategy. The projection operator is used for the purpose of robustness of the adaptive control algorithm. The stability of the proposed nonlinear robust adaptive controller is demonstrated applying the Lyapunov stability theory. The performance of the proposed controller is compared with two previous successful algorithms, which are implemented on the Generic Transport Model airplane to accommodate wing damage. Numerical simulations demonstrate the effectiveness and advantages of the proposed robust adaptive algorithm regarding two other algorithms of adaptive sliding mode and L adaptive control.Öğe Partial engine fault detection and control of a Quadrotor considering model uncertainty(Murat Yakar, 2022) Asadi, DavoodThis paper presents a trajectory tracking fault-tolerant control strategy inside an autonomous emergency landing architecture to control a quadrotor in case of partial rotor fault. The proposed architecture, which is composed of required hardware and subsystems, aims to ensure a fully autonomous safe landing of the impaired quadrotor to a suitable landing site. The controller strategy, which is tried to be coincident with the proposed emergency landing architecture and the Pixhawk autopilot contains a cascade three-loop structure of adaptive sliding mode and a modified PID algorithm along with a fault detection algorithm. The adaptive sliding mode and the PID algorithms are applied to the fast dynamics of angular velocity rates and the position control of the quadrotor, respectively. A lightweight fault detection algorithm is developed to detect and identify the partial faults of engine using the controller outputs and the filtered angular rates. The simulation results demonstrate that the proposed fault-tolerant controller can control the multi-rotor in partial engine faults with satisfactory tracking performance. The results also demonstrate the effect of fault detection time delay on the overall control performance. © Author(s) 2021.Öğe Performance-based emergency landing trajectory planning applying meta-heuristic and Dubins paths(Elsevier, 2022) Haghighi, Hassan; Delahaye, Daniel; Asadi, DavoodEmergency Landing is a complex problem of optimal path planning of an impaired airplane in presence of obstacles, while the airplane performance characteristics have degraded. Some in-flight failures can affect the airplane dynamics and therefore the new dynamic constraints must be considered in flight planning to the desired landing site. This paper introduces a novel hybrid form of Dubins-simulated annealing (HDSA) optimization framework for emergency landing. The proposed architecture applies Dubins paths and Apollonius' tangent line to generate candidate pieces of trajectories respecting the post-failure performance characteristics of the distressed airplane. The optimization pattern is used to select the optimal combination of the candidate trajectories based on the cost functions and the environmental constraints to lead the airplane to the desired landing site. Analytical performance based equations are developed to achieve an admissible solution in emergency trajectory planning. The goal is to provide a general optimal framework, which can enhance the flight management system by assisting the pilot to plan the most suitable and admissible trajectory to the landing site in emergency flight conditions. The effectiveness of the proposed approach is demonstrated through simulations. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
