Browse Topic: Flight dynamics
Urban Air Mobility (UAM) envisions heterogenous airborne entities like crewed and uncrewed passenger and cargo vehicles within, and between urban and rural environment. To achieve this, a paradigm shift to a cooperative operating environment similar to Extensible Traffic Management (xTM) is needed. This requires the blending of traditional Air Traffic Services (ATS) with the new generation UAM vehicles having their unique flight dynamics and handling characteristics. A hybrid environment needs to be established with enhanced shared situational awareness for all stakeholders, enabling equitable airspace access, minimizing risk, optimized airspace use, and providing flexible and adaptable airspace rules. This paper introduces a novel concept of distributed airspace management which would be apt for all kinds of operational scenarios perceived for UAM. The proposal is centered around the efficiency and safety in air space management being achieved by self-discipline. It utilizes
A novel geometry for a six degrees of freedom (6DOF) unmanned aerial vehicle (UAV) rotary wing aircraft is introduced and a flight mechanical analysis is conducted for an aircraft built in accordance to the thrust vectors of the proposed geometry. Furthermore, the necessary mathematical operations and control schemes are derived to fly an aircraft with the proposed geometry. A system identification of the used propulsion system with the necessary thrust reversal in the form of bidirectional motors and propellers was conducted at a whirl tower. The design of the first prototype aircraft is presented as well as the first flight test results. It could be demonstrated that an aircraft with the thrust vectors oriented according to the proposed geometry works sufficiently and offers unique maneuvering capabilities that cannot be reached with a conventional design. The biggest limiting factor could be identified to be the latency resulting from the time needed to reverse the direction of
Fighter pilots must study models of aircraft dynamics before learning complex maneuvers and tactics. Similarly, autonomous fighter aircraft applications may benefit from a model-based learning approach. Instead of using a preexisting physics model of a given aircraft, a machine learning system can learn a predictive model of the aircraft physics from training data. Furthermore, it can model interactions between multiple friendly aircraft, enemy aircraft, and the environment. Such a system can also learn to represent state variables that are not directly observable, as well as dynamics that are not hard coded. Existing model-based methods use a deep neural network that takes observable state information and agent actions as input and provides predictions of future observations as output. The proposed method builds upon this approach by adding a residual feedforward skip connection from some of the inputs to all of the outputs of the deep neural network. Further innovations address
Unmanned Aerial Vehicles (UAVs) have been widely used to carry cameras, sensors or products for applications such as mapping, frame monitoring, goods delivery, entertainment and more. The most common UAVs are powered by battery only, which limits the duration of operation. However, current batteries of the system depending on vehicle, payload, and wind conditions enable only flights up to 30 min for quadrotors, which can limit the usage of these UAVs for long time missions and experiments
The largest supersonic parachute ever developed is one of the test articles on the Supersonic Flight Dynamics Test (SFDT) vehicle of the Low Density Supersonic Decelerator (LDSD) project. The typical method for deploying a supersonic parachute from an entry vehicle, by firing it from a mortar, is not viable for this application due to its noncentral location on the vehicle and the associated high reaction force. Instead, the parachute is pulled off the vehicle using the Parachute Deployment Device (PDD). The PDD uses a ballute, a smaller, balloon-like, soft-good drag body that maintains positive internal pressure by ingesting air at supersonic speeds through a set of ram-air inlets. The PDD, being significantly smaller than the supersonic parachute, is deployed using a mortar
Adopters of the AIAA/ANSI Standard S119, “Flight Dynamics Model Exchange Standard,” are required to deal with models encoded using DAVE-ML, an XML grammar. While examining the model via a text editor, the ability to visualize nonlinear mappings between input and output signals is not easy. This innovation provides a simple, easy-to-use, standalone Java application that provides the capability to examine the response of the model to combinations of input values. The models are encoded in XML, which is text-based
Micro aerial vehicles (MAVs) are agile and have unstable flight dynamics. They require a failsafe method to be navigated through areas even without GPS coverage. The approach of this work is to use only the feature matches between two consecutive images, i.e. optical flow (OF) and inertial cues. The vehicle’s pose and additional intrinsic as well as extrinsic states are estimated continuously to navigate and control the MAV through the area. Optical flow cues and inertial measurement readings are fused in an EKF (extended Kalman filter) framework to estimate a metric 3D body velocity, terrain plane-parameters, terrain plane relative 3D attitude including heading, and metric distance between the camera on the MAV and this plane. The estimates of the EKF provide the vehicle controller with accurate information about the vehicle and the environment in order to navigate the micro-helicopter autonomously through large areas. The system is fully self-contained and all computation is done
Satellite Situation Update (SSUP) software shows the current locations of a selected set of orbiting spacecraft, along with each satellite’s ground track and/or orbit shape. SSUP is intended as a real-time display, showing multiple spacecraft, that is suitable for a large wall monitor meant to be in public spaces for the appreciation of a wider audience. Satellite positions are constantly updated to stay current, based on either publicly available information (e.g. Celestrak) or other sources [by arrangement with Flight Dynamics Facility (FDF)]. The user chooses the spacecraft to be monitored, as well as other configuration parameters. SSUP is intended for education and outreach purposes; it is a way for an organization to, for example, take pride in the spacecraft they had a role in building or operating. SSUP also is an attractive way to stimulate interest in Earth-Sun-Moon relationships and basic orbital geometries
This paper summarizes the recent development of an adaptive aeroelastic wing shaping control technology called variable camber continuous trailing edge flap (VCCTEF). As wing flexibility increases, aeroelastic interactions with aerodynamic forces and moments become an increasingly important consideration in aircraft design and aerodynamic performance. Furthermore, aeroelastic interactions with flight dynamics can result in issues with vehicle stability and control. The initial VCCTEF concept was developed in 2010 by NASA under a NASA Innovation Fund study entitled “Elastically Shaped Future Air Vehicle Concept,” which showed that highly flexible wing aerodynamic surfaces can be elastically shaped in-flight by active control of wing twist and bending deflection in order to optimize the spanwise lift distribution for drag reduction. A collaboration between NASA and Boeing Research & Technology was subsequently funded by NASA from 2012 to 2014 to further develop the VCCTEF concept. This
Multi-Sensor Data Fusion (MSDF) techniques involving satellite and inertial-based sensors are widely adopted to improve the navigation solution of a number of mission- and safety-critical tasks. Such integrated Navigation and Guidance Systems (NGS) currently do not meet the required level of performance in all flight phases of small Remotely Piloted Aircraft Systems (RPAS). In this paper an innovative Square Root-Unscented Kalman Filter (SR-UKF) based NGS is presented and compared with a conventional UKF governed design. The presented system architectures adopt state-of-the-art information fusion approach based on a number of low-cost sensors including; Global Navigation Satellite Systems (GNSS), Micro-Electro-Mechanical System (MEMS) based Inertial Measurement Unit (IMU) and Vision Based Navigation (VBN) sensors. Additionally, an Aircraft Dynamics Model (ADM), which is essentially a knowledge based module, is employed to compensate for the MEMS-IMU sensor shortcomings in high-dynamics
An airplane model is usually obtained from preliminary wind tunnel experiments and CFD analysis. These models are then tuned from flight test measurements using system identification, and are used for airplane stability assessment and control design. However, sometimes no or little preliminary data and documentation are available and flight test identification is the main mean to obtain the model needed for control system design. If so, the purpose of this paper is to identify the grey-box model of an airplane without initial data using a combination of the least square and output error estimation methods. A grey-box model identification is preferred because it gives aerodynamic parameter estimations of the airplane. Before flight test data are available, this method was applied to the Cessna Citation X business airplane's high fidelity simulations and carried out with human-in-the-loop on a professional level D flight dynamics simulator designed and manufactured by CAE Inc. More than
Vives College University and Kulab (KU Leuven University campus Ostend) in Belgium are undertaking an aeronautical research program about the development of a new Unmanned Aerial Vehicle (UAV). Since the UAV is completely electrically powered, the analysis of the energy management of the integrated electrical system was critical to the development of the UAV. LMS, A Siemens Business, is involved in the project to support the development of a multi-physics simulation model for electro-thermal analysis of the aircraft. This paper reports on the subsequent investigation of integrating the detailed electrical system model for a Pilot-in-the-Loop simulation. In order to perform this simulation, the model of the electrical system was converted into a real-time simulation model. The aim was to perform more realistic flight simulations to evaluate the performance of the aircraft before its first flight by taking into account the electrical system's behavior. Furthermore, the behavior of the
In this paper it is presented an analysis of the longitudinal and lateral-directional stability characteristics of paragliders. The paragliders stability analysis is part of the thesis named “Paragliders Flight Dynamics”, submitted to the Department of Mechanical Engineering of the Federal University of Minas Gerais (UFMG) - Brazil - in partial fulfillment of the requirements to obtain the master's degree in mechanical engineering. The full thesis presents a complete theoretical analysis of paragliders flight dynamics providing useful information for paragliders conceptual design optimization, and representing a first initiative to incentivize the international aeronautical engineering community to dedicate attention to this particular field
Global aviation is growing exponentially and there is a great emphasis on trajectory optimization to reduce the overall environmental impact caused by aircraft. Many optimization techniques exist and are being studied for this purpose. The CLEAN SKY Joint Technology Initiative for aeronautics and Air transport, a European research activity run under the Seventh Framework program, is a collaborative initiative involving industry, research organizations and academia to introduce novel technologies to improve the environmental impact of aviation. As part of the overall research activities, “green” aircraft trajectories are addressed in the Systems for Green Operations (SGO) Integrated Technology Demonstrator. This paper studies the impact of large commercial aircraft trajectories optimized for different objectives applied to the on board systems. It establishes integrated systems models for both conventional and more electric secondary power systems and studies the impact of fuel, noise
Added masses computation is a crucial aspect to be considered when the density of a body moving in a fluid is comparable to the density of the fluid displaced: added mass can be defined as the inertia added to a system because an accelerating or decelerating body displaces some volume of neighboring fluid as it moves through it. The motion of vehicles like airships and ships can be addressed only by keeping into account the effect of added masses, while in case of aircrafts and helicopters this contribution is usually neglected. Lighter Than Air flight simulation, unmanned airships flight control system, airships flight dynamics are typical applications in which added masses are fundamental to achieve an effective and realistic modeling. A panel based method using the mesh of an airship external shape is developed to account for the added massed. While the mathematical background of the methodology is described in literature, what is missing is a proper description suitable for
In this paper we present results of a study of an integrated aero-propulsion flight control system. The resulting problem is that of controlling the system in which actuators operate on different time scales. This is a difficult problem since the control strategy needs to balance between not using the slow actuator at all, and slowing down the overall system to the time scale of the slow actuator. In the case of aero-propulsion control design for F/A-18 aircraft, the part of the control derivative matrix associated with engines is not full rank so not all states of interest can be simultaneously forced to track the commands. A control strategy that takes this constraint into account has been developed. The proposed IRAP approach is illustrated through simulation of F/A-18 aircraft dynamics under flight-critical control effector failures
In the development of High Altitude Long Endurance (HALE) UAVs and their control the flexibility of the wing must be taken into account. The wing of this type of UAVs, usually made of highly flexible composite materials, has high aspect ratio with significant bending-torsional deformation during flight. The NASA Helios, as an example, has tragically shown that wing deformation coupled with control and power operation can cause serious problem in flight, instability can suddenly occur and can be quite difficult to foresee. In this paper the mathematical description of a flexible wing multibody model is presented. It is suitable to simulate the effect of both structural flexibility and flight dynamics and maneuvering on the wing deformation, and can be used to help developing control strategies for air vehicles with highly deformable wings. The paper will present simulation results for a typical HALE (High Altitude Long Endurance) wing with control surfaces and the effect of flexibility
Within the European Integrated Project NACRE (New Aircraft Concept REsearch) led by Airbus, a team of research centers and universities developed a multidisciplinary flying testbed called IEP (Innovative Evaluation Platform). Under the form of a dynamically scaled model of a future civil transport aircraft, its role is to assist engineers during the assessment of flight dynamics characteristics and noise reduction capabilities. After the feasibility study during which potential scientific and economical benefits of such new test facility have been identified, the team decided to design and manufacture the IEP. Because of the dual aspect of the system (it is a flying unmanned aerial vehicle and a test facility), an extensive requirement analysis has been carried out by the partners in order to identify the necessary operational modes and their associated navigation and control strategies. The navigation algorithm implemented in the IEP is based on a control geometry around the airplane
Touch Screen technologies have evolved to the point that several solutions are rugged enough to be introduced into the cockpit. Any selected solution has its particular pros and cons, and using current state-of-the-art technology will always result in a compromise. A Touch Screen interface allows a more intuitive operation, reducing workload for the pilot and co-pilot, and thus increasing safety. It is believed that multi-touch capabilities are beneficial in cockpit applications. Looking to the future, research will be needed to develop the right solutions for haptic feedback mechanisms and to minimize the effects of fingerprint residue on the screen. The effects of the aircraft's dynamics on the usability of the Touch Screen will also need to be analyzed and will impact the definition of the Human Machine Interface (HMI). This paper presents a display manufacturer's technological view on the applicability of Touch Screens in the aircraft cockpit
XFDS provides an easily adaptable automation platform. To date it has been used to support flight dynamics operations. It coordinates the execution of other applications such as Satellite TookKit, FreeFlyer, MATLAB, and Perl code. It provides a mechanism for passing messages among a collection of XFDS processes, and allows sending and receiving of GMSEC messages. A unified and consistent graphical user interface (GUI) is used for the various tools. Its automation configuration is stored in text files, and can be edited either directly or using the GUI
DTV-SIM is a computer program that implements a mathematical model of the flight dynamics of a missile-shaped drop test vehicle (DTV) equipped with a multistage parachute system that includes two simultaneously deployed drogue parachutes and three main parachutes deployed subsequently and simultaneously by use of pilot parachutes. DTV-SIM was written to support air-drop tests of the DTV/parachute system, which serves a simplified prototype of a proposed crew capsule/parachute landing system
The Orbit Determination Toolbox is an orbit determination (OD) analysis tool based on MATLAB and Java that provides a flexible way to do early mission analysis. The toolbox is primarily intended for advanced mission analysis such as might be performed in concept exploration, proposal, early design phase, or rapid design center environments. The emphasis is on flexibility, but it has enough fidelity to produce credible results. Insight into all flight dynamics source code is provided
Gliders can climb to substantial altitudes without employing any on-board energy resources but using proper piloting skills to utilize rising air currents called thermals. Recent experiments on small Unmanned Aerial Vehicles (UAVs) indicate a significant potential to increase both the flight velocity and the range of gliders by means of such maneuvers. In these experiments the velocity to approach a thermal has been recognized as a critical performance factor, and is chosen as the controlled variable. Accurate longitudinal controllers are required to track the optimal flight trajectories generated using path planning algorithms. These controllers are challenged by the presence of uncertain and time-varying aircraft dynamics, gust disturbances, and control actuator limitations. With a broader objective of utilizing thermals to optimize the flight performance of autonomous UAVs, we focus on handling elevator constraints imposed on an uncertain aircraft model whose parameters are
focusLEO Low-Earth Orbit (LEO) flight dynamics software GMV Rockville, MD 301-926-0119
A software library has been developed to enable high-fidelity computational simulation of the dynamics of multiple spacecraft distributed over a region of outer space and acting with a common purpose. All of the modeling capabilities afforded by this software are available independently in other, separate software systems, but have not previously been brought together in a single system. A user can choose among several dynamical models, many high-fidelity environment models, and several numerical-integration schemes. The user can select whether to use models that assume weak coupling between spacecraft, or strong coupling in the case of feedback control or tethering of spacecraft to each other. For weak coupling, spacecraft orbits are propagated independently, and are synchronized in time by controlling the step size of the integration. For strong coupling, the orbits are integrated simultaneously. Among the integration schemes that the user can choose are Runge-Kutta Verner, Prince
In aeroservoelastic (ASE)-stability analysis, one considers the coupling of the aerodynamic, inertial, structural, actuation, and control-system elements of the dynamics of an aircraft. The closed-loop interactions of these elements can introduce unexpected instabilities in flight if the analytical model used for synthesis and analysis is not accurate. Measures of allowable flight-condition variations, called "stability margins," should be computed to indicate the range of velocities and altitudes within which the aircraft can safely operate
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