223 research outputs found
Design and implementation of UAV performance validation system
Abstract. This thesis aims for design and implementation of a system for drone performance measurements, which can be used for validation of different drones for research projects accordingly. Additionally, the device should be able to be used as a part of a hardware-in-loop -system with simulators in drone research. The primary goal for this thesis is to build a system which helps to document different drone properties efficiently and safely. This is done with a system that consists of a robust frame, a force and torque measuring transducer, a drone stabilizing unit, a data logging system, and a remote-control power supply. For controlling the system, user interface was created to control the data stream, the drone stabilizing unit, and the power supply.
This thesis includes a literature review of drone general classification properties and legal regulations. Short review of drone usage and selection criteria in industry and research is conducted, as well as in-depth review of the drone components and their relation to overall performance of the drone. The thesis also contains literature review of force and torque measuring theory, and other drone performance measuring units. The functionality of the designed unit is tested by building a drone from spare components, and valuating its performance based on e.g., lift generation, power consumption and visual behavior of the drone. Measured data is documented, and with the documents, drone’s suitability for future research projects can be assessed. According to the results, the unit can be used to evaluate drone’s performance, and groundwork for Hardware-in-loop simulator connection for drone research. The testing unit and the data recordings as well as the built testing drone stays within the research facility for further development.UAV testausjärjestelmän suunnittelu ja toteutus. Tiivistelmä. Tässä diplomityössä suunnitellaan ja valmistetaan droonien suorituskykyä mittaava tutkimuslaitteisto, jonka avulla voidaan arvioida erilaisten droonien soveltuvuutta tutkimusprojekteihin tapauskohtaisesti. Työssä tavoitellaan helppokäyttöistä järjestelmää, jonka avulla itse tehtyjen droonien ominaisuuksia voidaan dokumentoida turvallisesti ja tehokkaasti. Työssä perehdytään droonien luokitteluun tutustumalla voimassa oleviin säädöksiin, sekä droonin suorituskykyä kuvaaviin ominaisuuksiin. Työssä tarkastellaan droonien käyttöä eri aloilla arvioiden esiin nousseita droonin valintaperusteita ja ominaisuuksia. Tämän jälkeen tutustutaan droonien rakenteeseen ja ominaisuuksiin. Voiman mittauksen teoriaan sekä kehitettyihin mittausmenetelmiin tutustutaan tukemaan anturivalintaa. Suunniteltu järjestelmä koostuu tukevasta rungosta, voiman mittaukseen soveltuvasta anturista, droonin vakauttamisen kokonaisuudesta, datan keräysjärjestelmästä sekä etäohjattavasta virtalähteestä. Laitteiston ohjaukseen luotiin rajapinta, jonka kautta järjestelmää voidaan hallita. Järjestelmän toimivuus todettiin kahdella mittauskäyttöön soveltuvalla droonilla, joiden suorituskykyä arvioitiin droonien ominaisuuksien, sekä visuaalisen käyttäytymisen avulla. Mittauksien tulokset dokumentoitiin, ja dokumentaation perusteella voidaan arvioida sekä tutkimuslaitteiston toimivuutta, että mitattujen droonien soveltuvuutta tulevissa tutkimusprojekteissa. Mittausten perusteella voidaan todeta laitteen soveltuvan droonien suorituskyvyn mittaamiseen, sekä pohjatyöksi simulaattorikytkentään. Mittalaitteisto sekä mittaustulokset jäävät Biomimetiikka ja älykkäät järjestelmät -tutkimusyksikön käyttöön droonitutkimuksen tueksi
Propulsion system study for ONAerospace eVTOL
This is a project whose main objective is to determine the required values of thrust, power, and efficiency for the propulsion systems of the ONA DLC eVTOL aircraft by ONAerospace during the hover and cruise phases. Additionally, it is an investigation work on both open propeller and ducted fan propulsion systems.Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i InfraestructuraObjectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenible
Set-based state estimation and fault diagnosis using constrained zonotopes and applications
This doctoral thesis develops new methods for set-based state estimation and
active fault diagnosis (AFD) of (i) nonlinear discrete-time systems, (ii)
discrete-time nonlinear systems whose trajectories satisfy nonlinear equality
constraints (called invariants), (iii) linear descriptor systems, and (iv)
joint state and parameter estimation of nonlinear descriptor systems. Set-based
estimation aims to compute tight enclosures of the possible system states in
each time step subject to unknown-but-bounded uncertainties. To address this
issue, the present doctoral thesis proposes new methods for efficiently
propagating constrained zonotopes (CZs) through nonlinear mappings. Besides,
this thesis improves the standard prediction-update framework for systems with
invariants using new algorithms for refining CZs based on nonlinear
constraints. In addition, this thesis introduces a new approach for set-based
AFD of a class of nonlinear discrete-time systems. An affine parametrization of
the reachable sets is obtained for the design of an optimal input for set-based
AFD. In addition, this thesis presents new methods based on CZs for set-valued
state estimation and AFD of linear descriptor systems. Linear static
constraints on the state variables can be directly incorporated into CZs.
Moreover, this thesis proposes a new representation for unbounded sets based on
zonotopes, which allows to develop methods for state estimation and AFD also of
unstable linear descriptor systems, without the knowledge of an enclosure of
all the trajectories of the system. This thesis also develops a new method for
set-based joint state and parameter estimation of nonlinear descriptor systems
using CZs in a unified framework. Lastly, this manuscript applies the proposed
set-based state estimation and AFD methods using CZs to unmanned aerial
vehicles, water distribution networks, and a lithium-ion cell.Comment: My PhD Thesis from Federal University of Minas Gerais, Brazil. Most
of the research work has already been published in DOIs
10.1109/CDC.2018.8618678, 10.23919/ECC.2018.8550353,
10.1016/j.automatica.2019.108614, 10.1016/j.ifacol.2020.12.2484,
10.1016/j.ifacol.2021.08.308, 10.1016/j.automatica.2021.109638,
10.1109/TCST.2021.3130534, 10.1016/j.automatica.2022.11042
Advanced Feedback Linearization Control for Tiltrotor UAVs: Gait Plan, Controller Design, and Stability Analysis
Three challenges, however, can hinder the application of Feedback
Linearization: over-intensive control signals, singular decoupling matrix, and
saturation. Activating any of these three issues can challenge the stability
proof. To solve these three challenges, first, this research proposed the drone
gait plan. The gait plan was initially used to figure out the control problems
in quadruped (four-legged) robots; applying this approach, accompanied by
Feedback Linearization, the quality of the control signals was enhanced. Then,
we proposed the concept of unacceptable attitude curves, which are not allowed
for the tiltrotor to travel to. The Two Color Map Theorem was subsequently
established to enlarge the supported attitude for the tiltrotor. These theories
were employed in the tiltrotor tracking problem with different references.
Notable improvements in the control signals were witnessed in the tiltrotor
simulator. Finally, we explored the control theory, the stability proof of the
novel mobile robot (tilt vehicle) stabilized by Feedback Linearization with
saturation. Instead of adopting the tiltrotor model, which is over-complicated,
we designed a conceptual mobile robot (tilt-car) to analyze the stability
proof. The stability proof (stable in the sense of Lyapunov) was found for a
mobile robot (tilt vehicle) controlled by Feedback Linearization with
saturation for the first time. The success tracking result with the promising
control signals in the tiltrotor simulator demonstrates the advances of our
control method. Also, the Lyapunov candidate and the tracking result in the
mobile robot (tilt-car) simulator confirm our deductions of the stability
proof. These results reveal that these three challenges in Feedback
Linearization are solved, to some extents.Comment: Doctoral Thesis at The University of Toky
Analysis of the performance and kinematics of the movement of UAV
The use of drones today has become an integral part of modern life to the extent that the level of drone utilization determines the quality of life. The expansion of drone applications has grown exponentially. This growth is primarily due to their low acquisition and maintenance costs, as well as their versatility. First of all, their expansion is contributed by the low costs of both acquisition and maintenance, as well as the possibility of various applications. The paper aims to present drones and their advantages compared to traditional aircraft as a means of transportation. The paper includes an analysis of unmanned aircraft performance, an examination of the kinematics of unmanned aircraft movement, a discussion of the most common structure used in unmanned aircraft (the quadcopter), and a comprehensive assessment of the risks associated with unmanned aircraft and their potential integration into civil air traffic. The quadcopter structure, as the dominant solution for the production of unmanned aircraft, is discussed in detail. At the very end, an overall analysis of the risks posed by unmanned aircraft and, as such, whether they can be integrated into civil air traffic is given
Get Your Cyber-Physical Tests Done! Data-Driven Vulnerability Assessment of Robotic Vehicle
The rapid growth of robotic aerial vehicles (RAVs) has attracted extensive interest in numerous public and civilian applications, from flying drones to quadrotors. Security of RAV systems has become increasingly challenging as RAV controller software becomes more complex, exposing a growing attack surface. Memory isolation separates the memory space and enforces memory access control via privilege separation to limit the attacker’s capability so that the attacker cannot compromise other software components by exploiting one memory corruption vulnerability. Memory isolation has been adopted into the resource-constrained systems such as RAVs by lightweight privilege mode switching to meet real-time requirements.
In this paper, we propose ARES, a new variable-level vulnerability excavation framework to find deeper bugs from a combined cyber-physical perspective. We present a data-driven method to illustrate that, despite state-of-the-art memory isolation efforts, RAV systems are still vulnerable to adversarial data manipulation attacks. We augment RAV control states with intermediate controller variables by tracing accessible control parameters and vehicle dynamics within the same isolated memory regions. With this expanded state variable space, we apply multivariate statistical analysis to investigate inter-variable quantitative data dependencies and search for vulnerable state variables. ARES utilizes a learning-based method to show how an attacker can exploit memory corruption bugs in a legitimate memory view and elaborately craft adversarial variable values to disrupt a RAV’s safe operations. We demonstrate the feasibility and capability of ARES on the widely-used Ardupilot RAV framework. Our extensive empirical evaluation shows that the attacker may leverage these vulnerable state variables to achieve various RAV failures during its real-time operations, and even evade existing defense solutions
Generalized Two Color Map Theorem -- Complete Theorem of Robust Gait Plan for a Tilt-rotor
Gait plan is a procedure that is typically applied on the ground robots,
e.g., quadrupedal robots; the tilt-rotor, a novel type of quadrotor with eight
inputs, is not one of them. While controlling the tilt-rotor relying on
feedback linearization, the tilting angles (inputs) are expected to change
over-intensively, which may not be expected in the application. To help
suppress the intensive change in the tilting angles, a gait plan procedure is
introduced to the tilt-rotor before feedback linearization. The tilting angles
are specified with time in advance by users rather than given by the control
rule. However, based on this scenario, the decoupling matrix in feedback
linearization can be singular for some attitudes, combinations of roll angle
and pitch angle. It hinders the further application of the feedback
linearization. With this concern, Two Color Map Theorem is established to
maximize the acceptable attitude region, where the combinations of roll and
pitch will give an invertible decoupling matrix. That theorem, however,
over-restricts the choice of the tilting angles, which can rule out some
feasible robust gaits. This paper gives the generalized Two Color Map Theorem;
all the robust gaits can be found based on this generalized theorem. The
robustness of three gaits that satisfy this generalized Two Color Map Theorem
(while violating Two Color Map Theorem) are analyzed. The results show that
Generalized Two Color Map Theorem completes the search for the robust gaits for
a tilt-rotor
Avian-Inspired Claws Enable Robot Perching or Walking
Multimodal UAVs (Unmanned Aerial Vehicles) are rarely capable of more than
two modalities, i.e., flying and walking or flying and perching. However, being
able to fly, perch, and walk could further improve their usefulness by
expanding their operating envelope. For instance, an aerial robot could fly a
long distance, perch in a high place to survey the surroundings, then walk to
avoid obstacles that could potentially inhibit flight. Birds are capable of
these three tasks, and so offer a practical example of how a robot might be
developed to do the same. In this paper, we present a specialized
avian-inspired claw design to enable UAVs to perch passively or walk. The key
innovation is the combination of a Hoberman linkage leg with Fin Ray claw that
uses the weight of the UAV to wrap the claw around a perch, or hyperextend it
in the opposite direction to form a curved-up shape for stable terrestrial
locomotion. Because the design uses the weight of the vehicle, the
underactuated design is lightweight and low power. With the inclusion of
talons, the 45g claws are capable of holding a 700g UAV to an almost 20-degree
angle on a perch. In scenarios where cluttered environments impede flight and
long mission times are required, such a combination of flying, perching, and
walking is critical.Comment: 15 pages, 12 figure
Utilisation of drones in wind measurements: an analysis of wind data gathered with a drone-bound ultrasonic anemometer
In this thesis we try to find the measurement accuracy of our dronebound wind measurement setup and if the quality of the measurements is high enough for operational usage. The thesis goes over the most important theoretical concepts concerning effects of wind in the boundary layer.
In the thesis we analyze wind data gathered by a drone-bound anemometer, and introduce a direct method of measuring wind with a UAV. The data includes stationary wind data gathered at height of 30 metres, as well as vertical wind profiles to 500 metres above ground level. The data is compared to reference data from a 30 metre wind mast and automatic radiosoundings. The measurements were conducted in Jokioinen, Finland between the 2nd of September 2022 and 10th of October 2022. Total of 20 measurement flights were conducted, consisting of 14 stationary wind measurements and six wind profile measurements.
We found out the stationary wind measurement quality to be comparable with earlier studies. The vertical wind profile measurements were found to be hard to analyze, as the reference measurement was not as compatible as we had hoped for. The difference between automatic radiosoundings and our profile measurements was distinctly greater than the difference between the stationary drone and wind mast measurements.
Lastly some optimization and improvements to the measurement arrangement are discussed. The application of these improvements and modifications will be left as future endeavour for some willing individual
Swashplateless-elevon Actuation for a Dual-rotor Tail-sitter VTOL UAV
In this paper, we propose a novel swashplateless-elevon actuation (SEA) for
dual-rotor tail-sitter vertical takeoff and landing (VTOL) unmanned aerial
vehicles (UAVs). In contrast to the conventional elevon actuation (CEA) which
controls both pitch and yaw using elevons, the SEA adopts swashplateless
mechanisms to generate an extra moment through motor speed modulation to
control pitch and uses elevons solely for controlling yaw, without requiring
additional actuators. This decoupled control strategy mitigates the saturation
of elevons' deflection needed for large pitch and yaw control actions, thus
improving the UAV's control performance on trajectory tracking and disturbance
rejection performance in the presence of large external disturbances.
Furthermore, the SEA overcomes the actuation degradation issues experienced by
the CEA when the UAV is in close proximity to the ground, leading to a smoother
and more stable take-off process. We validate and compare the performances of
the SEA and the CEA in various real-world flight conditions, including
take-off, trajectory tracking, and hover flight and position steps under
external disturbance. Experimental results demonstrate that the SEA has better
performances than the CEA. Moreover, we verify the SEA's feasibility in the
attitude transition process and fixed-wing-mode flight of the VTOL UAV. The
results indicate that the SEA can accurately control pitch in the presence of
high-speed incoming airflow and maintain a stable attitude during fixed-wing
mode flight. Video of all experiments can be found in
youtube.com/watch?v=Sx9Rk4Zf7sQComment: 8 pages, 13 figure
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