Bálint Vanek

Hungarian Academy of Sciences | HAS · Systems and Control Lab

Active flutter suppression (AFS) was demonstrated in real-life conditions during the project FLIPASED (Flight Phase Adaptive Aero-Servo-Elastic Aircraft Design Methods). It was done by passing the flutter speed with a subscale demonstrator called P-FLEX. Two different flutter suppression controllers were used in this case, both of which proved to d...

Recently, high accuracy and low-cost navigation hardware is becoming increasingly available that can be efficiently used for the control of autonomous vehicles. We present a sensor fusion method providing tightly coupled integration of pseudorange, carrier phase, and Doppler satellite measurements taken at multiple vehicle-mounted GNSS antennas wit...

We present a position and attitude estimation algorithm of moving platforms based on the tightly coupled sensor fusion of low-cost multi baseline GNSS, inertial, magnetic and barometric observations obtained by low-cost sensors and affordable dual-frequency GNSS receivers. The sensor fusion algorithm is realized by an Extended Kalman Filter and est...

In the analysis of uncertain systems, we often search for a worst case perturbation that drives the $H_\infty $ gain of the system to the maximum over the set of allowable uncertainties. Employing the classical technique, an uncertainty sample is obtained, which, indeed, maximizes the gain but only at the single frequency where that maximum occur...

This article focuses on the validation of a classical PID controller scheme for flexible spacecraft with regards to the effect of parameter uncertainty on system stability and pointing precision. A high-fidelity simulation environment with external disturbances was built in Simulink using a control-oriented model of an Earth-observing satellite wit...

Unmanned aerial vehicles continue to drive innovative aircraft designs, introducing new challenges to the aeroelastic stability of aircraft. Hardware-in-the-Loop HIL systems provide a powerful platform for testing complex real time embedded systems. The challenges of identifying and tracking modal parameters as an indicator of flutter are still unr...

Structural flexibility of advanced, large-wingspan aircrafts is a crucial factor which has huge influence on the dynamics and stability of these vehicles. In case of a highly flexible wing structure, there is a need for an efficient observer to measure and predict the structural changes and dynamics of the wing. However, the modal coordinates of th...

This letter considers the instability of a Lurye system consisting of an uncertain, discrete-time, linear time-invariant plant in feedback with a slope-restricted nonlinearity. There is a large literature on analyzing the stability of such systems. This includes various conditions for proving stability of the Lurye system, including the Circle crit...

Model based Fault Detection and Isolation (FDI) in aerospace have received considerable attention and numerous algorithms are flying on-board commercial aircraft. Most of these algorithms are based on local models of aircraft components or rigid body aircraft models. On the other hand the ever more pressing requirement of performance and fuel effic...

The paper proposes a control design methodology for active flutter suppression for the aeroservoelastic (ASE) aircraft of the European project FLEXOP. The aim of the controller is to robustly stabilize the aeroelastic modes. The control design is based on a control‐oriented linear parameter‐varying (LPV) model, which is derived via “bottom–up” mode...

This article presents a method for structured robust control design for systems with a mixture of parametric and dynamic uncertainty. The proposed method alternates between an analysis step and a synthesis step. Samples of the parametric uncertainty are computed during the analysis steps, thus yielding an array of uncertain systems containing only...

Today several modelling and control synthesis methods are available to construct accurate aircraft representations and a large portion of these tools are appropriate for educational use. It is extremely beneficial for students studying in related areas to be able to construct and evaluate such vehicle systems, since it allows them to gain experienc...

High aspect ratio aircraft built from lighter and therefore more flexible materials are increasingly used in aviation. One of the challenges in designing a Fault Detection and Isolation (FDI) system for a flexible aircraft is to obtain an appropriate flexible model of it as opposed to rigid aircraft where modelling (or identification) is more tradi...

Hybrid-electric, unconventional aircraft solutions can possibly be the solutions for the ambitious emission reduction targets set by regulators, based on society's demands. One such disruptive solution is a morphing wing cargo UAV, with distributed propulsion. This paper investigates the aerodynamics, flight dynamics and control of a scaled down te...

This paper presents the modeling, system identification, simulation and flight testing of the airbrake of an unmanned experimental aircraft in frame of the FLEXOP H2020 EU project. As the aircraft is equipped with a jet engine with slow response an airbrake is required to increase deceleration after speeding up the aircraft for flutter testing in o...

The main direction of aircraft design today and in the future is to achieve more lightweight and higher aspect ratio airframes with the aim to improve performance and to reduce operating costs and harmful emissions. This promotes the development of flexible aircraft structures with enhanced aeroelastic behaviour. Increased aeroservoelastic (ASE) ef...

Ground testing campaign conducted on the FLEXOP demonstrator aircraft is presentedin this paper. The conducted tests are grouped in structural, flight system and integrationtests. Along with the description of the test setup and test execution, the main findingsand conclusions are also given. The structural tests comprise the static, ground vibrati...

The paper details the research and corresponding implementation and testing steps of the FLEXOP demonstrator aircraft. Within the EU funded project an unmanned demonstrator aircraft is built to validate the mathematical modelling, flight control design and implementation side of active flutter mitigation. In order to validate the different methods...

The idea of the EU funded FLEXOP project is to raise efficiency of a currently existing wing by derivative solution with higher aspect ratio at no excess structural weight. In order to enable such a resulting highly flexible wing the project goal is to develop methods for active suppression of flutter and passive load alleviation. The developed met...

Future aircraft tend to have increased flexibility that leads to increased aeroservoe-lastic (ASE) effects. Therefore, future aircraft control systems need active control to suppress ASE effects. Active flutter suppression can be effectively done in the linear parameter varying (LPV) framework. Control surface sizing for aircraft is traditionally d...

The presentation sums up the objectives, requirements and achivements within Work Package 1 of the Horizon 2020 Project FLEXOP. It is part of the dedicated FLEXOP-Project Session during the 9th EASN Conference, held September 2019 in Athens, Greece

Objective Flight Phase Adaptive Aero-Servo-Elastic Aircraft Design Methods (FliPASED) opens a complete new dimension for the integrated aircraft design. Coupling between aeroelasticity, gust response, flight control methods, instrumentation and certification aspects is not exploited in current aircraft design. A common set of models, coupled with j...

In this article the challenge of providing precise runway relative position and orientation reference to a landing aircraft based-on monocular camera and inertial sensor data is targeted in frame of the VISION EU H2020 research project. The sensors provide image positions of the corners of the runway and the so-called vanishing point and measured a...

A comprehensive design of the baseline control and navigation system for a single-jet-engined flutter demonstrator aircraft is presented in this paper. To facilitate the design task, a classical cascaded flight control structure is selected. Advanced robust control techniques are used to design and tune the individual feedback loops of the control...

This paper compares three model-based methods for detecting and isolating stuck control surface faults on a small unmanned aircraft. The first method is parity-space based and compares a sensor measurement against a model-based prediction of the same quantity. The second method is observer-based and involves robust estimation for linear parameter-v...

This paper appears twice on RG. As it is not possible to merge contributions manually, interested readers in the full text are refered to the full link: https://www.researchgate.net/publication/330198247_Flight_control_design_for_a_highly_flexible_flutter_demonstrator

This paper presents a flutter suppression control design methodology for the aircraft designed within the European research project, FLEXOP. The aim of the flutter suppression controller is to stabilize the aeroelastic modes and to extend the aircraft’s flutter free envelope. The first step is to develop a low order control oriented linear paramete...

In this article the challenge of providing precise runway relative position and orientation reference to a landing aircraft based-on monocular camera and inertial sensor data is targeted in frame of the VISION EU H2020 research project. The sensors provide image positions of the corners of the runway and the so-called vanishing point and measured a...

The paper introduces the in-flight fault detection and basic reconfiguration of a small unmanned aerial vehicle equipped with two elevons and an electric motor. The considered fault scenario is one control surface stuck at a given position during straight and level flight. The fault detection is solved with Multiple Model Adaptive Estimation consid...

A dynamic input reconfiguration architecture is proposed for overactuated aerial vehicles to accommodate actuator failures. The method is based on the dynamic nullspace computed from the linear parameter-varying model of the plant dynamics. If there is no uncertainty in the system, then any signal filtered through the nullspace has no effect on the...

The aeroservoelastic modeling of flexible structures leads in general to large dimensional linear parameter varying (LPV) models. These models are intractable by the most analysis and control synthesis algorithms. Therefore, efficient model order reduction methods are needed. This paper investigates two approaches. Both are based on decoupling the...

The aeroelastic flutter is an undamped oscillation that occurs on flexible structures placed into an airflow. It is caused by the interaction of the structural dynamics and the aerodynamics. Since it generally leads to structural failure, it has to be avoided. The paper proposes a complete framework for handling the aeroservoelastic behavior of aer...

The aeroelastic flutter is an undamped oscillation that occurs on flexible structures placed into an airflow. It is caused by the interaction of the structural dynamics and the aerodynamics. Since it generally leads to structural failure, it has to be avoided. The paper proposes a complete framework for handling the aeroservoelastic behavior of aer...

This paper addresses the problem of state estimation in the presence of unknown inputs if the system is dependent on an uncertain parameter. Multiple Model Adaptive Estimation is applied to state and unknown input observers. The theory is evaluated on an aircraft airspeed estimator algorithm. The developed algorithm is based-on linear time invarian...

In this paper the possibility to use the camera of the onboard sense and avoid system as an aid in unmanned aircraft attitude estimation is examined. At first, the error analysis of four image processing algorithms targeting the reconstruction of camera orientation change is done. Camera spatial resolution, sampling frequency (temporal resolution),...

Governmental organizations are currently developing standards for civil unmannedaircraft to operate safely in the national airspace. A key requirement for aircraft certification is reliability assessment. Traditional reliability assessment methods make assumptions that are overly restrictive when applied to unmanned aircraft. This paper presents a...

The paper presents a novel model order reduction technique for large-scale linear parameter varying (LPV) systems. The approach is based on decoupling the original dynamics into smaller dimensional LPV subsystems that can be independently reduced by parameter varying reduction methods. The decomposition starts with the construction of a modal trans...

The paper presents a novel model order reduction technique for large-scale linear parameter varying (LPV) systems. The approach is based on decoupling the original dynamics into smaller dimensional LPV subsystems that can be independently reduced by parameter varying reduction methods. The decomposition starts with the construction of a modal trans...

The sense and avoid (SAA) capability is a key issue in the integration of Unmanned Aircraft Systems (UAS) into the common airspace [1]. Besides the lack of a regulatory framework in most countries, some technological challenges are still not resolved which holds back routine UAS applications. Most UAS or Remotely Piloted Aircraft Systems (RPAS) hav...

This paper discusses the subject of unmeasurable parameter (or state) estimation. It presents a viable option for carrying out this task, as well as augmentations for mending its flaws. The selected basic method is Multiple Model Adaptive Estimation, using multiple Kalman Filters (KFs) in parallel to determine the current value of the parameter (or...

A reliability assessment framework is presented for small unmanned aerial vehicles. The analysis considers several candidate architectures with different numbers of controllable surfaces and servos. It is assumed that a servo fault detection algorithm is available and affected by known rates of false alarms and missed detections. The aircraft fligh...

Several camera rotation estimator algorithms are tested in simulations and on real flight videos in this paper. The aim of the investigation is to show the strengths and weaknesses of these algorithms in the aircraft attitude estimation task. The work is part of a research project where a low cost UAV is developed which can be integrated into the n...

In this paper a novel algorithm for distant aircraft detection for visual sense-and-avoid for UAV is presented. The algorithm uses local edge density to partition the frame into two types of regions. The first type is the unstructured or homogeneous part like sky region and the second part where there is a structured background, like high contrast...

This paper deals with the problem of monocular image parameter-based sense and avoid. It considers image parameters as decision variables and selects decision thresholds related to collision and non-collision scenarios. The main contri- bution is non-heuristic threshold selection. Another contribution is the characterization of possible intruder th...

A multi-level reconfiguration framework is proposed for fault tolerant control of over-actuated aerial vehicles, where the levels indicate how much authority is given to the reconfiguration task. On the lowest, first level the fault is accommodated by modifying only the actuator/sensor configuration, so the fault remains hidden from the baseline co...

This paper deals with the problem of trajectory tracking and definition in monocular vision based sense and avoid scenarios for small UAVs where the intruder aerial vehicle should be held in camera field of view. After defining effective field of view (EFOV) and introducing its possible calculation tracking of a triangular waveform trajectory by a...

Two different approaches for fault detection, the geometric and the detection filter based methods, are compared in the paper from practical aspects, using the linear parameter-varying (LPV) framework. Presenting two designs allows a comparison of global, system level, and local component level fault detection methods with special emphasis on their...

In this paper the results of the error analysis of four different feature point based attitude estimator algorithm is introduced. The algorithms was tested in simulation with realistic flight paths and camera models. With these results a best performing candidate algorithm can be chosen for a given focal-plane processor and for the given scenarios.

A multi-level reconfiguration framework is proposed for fault tolerant control of overactuated aerial vehicles, where the levels indicate how much authority is given to the reconfiguration task. On the lowest, first level the fault is accommodated by modifying only the actuator/sensor configuration, so the fault remains hidden from the baseline con...

The real world feasibility of a self-contained, purely vision based sense and avoid system, required for small unmanned aerial vehicles (UAV) is investigated in the present paper. No information is exchanged between aircrafts, only passive 2-D vision information is available to estimate the encountering traffic. The system is composed of three dist...

In this paper four camera pose estimation algorithms are investigated in simulations. The aim of the investigation is to show the strengths and weaknesses of these algorithms in the aircraft attitude estimation task. The work is part of a research project where a low cost UAV is developed which can be integrated into the national airspace. Two main...

In this paper sensor models, implementation aspects, and simulations and measurements obtained during the development of a fixed wing mini UAV are presented. The aim is to develop a low cost UAV which can be integrated into the national airspace (NAS). The sense-and-avoid (SAA) capability has to be reliably run by the UAV in any critical situations...

The aim of the paper is to present a dynamic control allocation architecture for the design and development of reconfigurable and fault-tolerant control systems in aerial vehicles. The baseline control system is designed for the nominal dynamics of the aircraft, while faults and actuator saturation limits are handled by the dynamic control allocati...

The present article details the development steps and experimental results obtained during the development of smart actuators used on mini unmanned aerial vehicles (UAV). The research effort is driven by the need of developing onboard health monitoring and diagnostics units for small size UAVs to improve their reliability. In the present all small...

This paper proposes a novel method for sensor allocation based fault tolerant control. Fault tolerance is achieved with optimal combination of healthy sensor sources while the baseline controller remains unchanged. The measurements are subjected to various sensor dynamics, hence the resulting sensor allocation framework is also dynamic. The propose...

This paper extends the LTI anti-windup compensator scheme proposed in [6] to linear parameter-varying (LPV) systems. Following the MRAW concept, the dynamical part of the compensator is formed by the exact copy of the plant. The design procedure is thus simplified to the construction of a parameter-dependent state feedback, which stabilizes the pla...

The aim of the paper is to present a supervisory decentralized architecture for the design and development of reconfigurable and fault-tolerant control systems in aerial vehicles. The performance specifications with respect to flight envelope and fault states are guaranteed by local controllers, while the coordination of these components is provide...