Single Aircraft Research Articles

Multiple-Aircraft-Conflict Resolution Under Uncertainties

A new method for efficient trajectory planning to resolve potential conflicts among multiple aircraft is proposed. A brief review of aircraft trajectory planning and conflict resolution methods is given first. Next, a new method is proposed that is based on a probabilistic conflict risk map using the predicted probability of conflict with the intention information of the intruders. The risk-map-based method allows the path planning algorithm to simultaneously account for many uncertainties affecting safety, such as positioning error, wind variability, and human errors. Following this, A* algorithm is used to find the cost-minimized trajectory for a single aircraft by considering all other aircraft as intruders. Search heuristic method is implemented to iterate the A* algorithm for all aircraft to optimize the trajectory planning. Convergence and computation efficiency of the proposed method are investigated in detail. Numerical examples are used to illustrate the effectiveness of the proposed method under several important scenarios for air traffic control, such as wind effects, non-cooperative aircraft, minimum disturbance of pilots, and deconflict with flight intent information. Several conclusions are drawn based on the proposed method.

Stabilization of a class of switched dynamic systems: the Riccati-equation-based Approach

Abstract Our paper deals with the stabilization of a class of time-dependent linear autonomous complex systems with a switched structure. The initially given switched dynamic system is assumed to be controlled by a specific state feedback strategy associated with the linear quadratic regulator (LQR) type control. The proposed control design guarantees stabilization of the closed-loop system for all of the possible location transitions. In the solution procedure of the Algebraic Riccati Equation related to the LQR control strategy, only the knowledge of the algebraic structure related to the switched system are needed. We prove that the proposed optimal LQR type state feedback control design stabilizes the closed-loop switched system for every possible active location. The theoretical approach proposed in this paper is finally applied to a model of the Single Wing Quadrotor Aircraft, when changing from its Quadrotor Flight Envelope to its Airplane Flight Envelope.

Design, development and testing of digital MEMS pressure sensor array for full-scale vibroacoustic measurements

This manuscript addresses design, development, and application of micro-electro-mechanical systems (MEMS) based digital pressure sensor array for vibroacoustic measurements. These vibroacoustic measurements were conducted on a A320 type single aisle aircraft demonstrator subjected to broadband as well as tonal excitations. Cabin noise levels were measured with both condenser microphones as well as digital MEMS pressure sensor array. The measured cabin noise shows strong qualitative as well as quantitative agreement between both type of measurement devises for full scale cabin noise measurements inside an aircraft demonstrator. The observed strong agreement is valid for both single wall (fuselage with thermal insulation) and double wall (fuselage with thermal insulation and trim panel) cabin noise measurements. Such strong agreement within 1.0 dB tolerance is significantly motivating for further development of reliable but low-cost MEMS based measurement devises and corresponding efficient data post-processing algorithms for full scale vibroacoustic measurements in general. Additionally, it is also demonstrated that the large number of MEMS based digital pressure sensors can be used in areas where the physical space constraints are high. This demonstration shows strong potential to derive additional vibroacoustic indicator for the development and the testing of future noise control solutions in a non-traditional way.

Multi-Aircraft Trajectory Collaborative Prediction Based on Social Long Short-Term Memory Network

Aircraft trajectory prediction is the basis of approach and departure sequencing, conflict detection and resolution and other air traffic management technologies. Accurate trajectory prediction can help increase the airspace capacity and ensure the safe and orderly operation of aircraft. Current research focuses on single aircraft trajectory prediction without considering the interaction between aircraft. Therefore, this paper proposes a model based on the Social Long Short-Term Memory (S-LSTM) network to realize the multi-aircraft trajectory collaborative prediction. This model establishes an LSTM network for each aircraft and a pooling layer to integrate the hidden states of the associated aircraft, which can effectively capture the interaction between them. This paper takes the aircraft trajectories in the Northern California terminal area as the experimental data. The results show that, compared with the mainstream trajectory prediction models, the S-LSTM model in this paper has smaller prediction errors, which proves the superiority of the model’s performance. Additionally, another comparative experiment is conducted on airspace scenes with aircraft interactions, and it is found that S-LSTM has a better prediction effect than LSTM, which proves the effectiveness of the former considering aircraft interaction.

Design of Stress Constrained SiC/SiC Ceramic Matrix Composite Turbine Blades

Abstract The structural and aerodynamic performance of a low aspect ratio SiC/SiC ceramic matrix composite (CMC) high pressure turbine (HPT) blade was determined. The application was a NASA notional single aisle aircraft engine to be available in the N + 3, beyond 2030, time frame. The notional rpm was maintained, and to satisfy stress constraints, the annulus area was constrained. This led to a low span blade. For a given clearance, low span blade is likely to have improved efficiency when shrouded. The efficiency improvement due to shrouding was found to strongly depend on the axial gap between the shroud and casing. Axial gap, unlike clearance or reaction, is not a common parameter used to correlate the efficiency improvement due to shrouding. The zero clearance stage efficiency of the low aspect ratio turbine was 0.920. Structural analyses showed that the rotor blade could be shrouded without excessive stresses. The goal was to have blade stresses less than 100 MPa (14.5 ksi) for the unshrouded blade. Under some not very restrictive circumstances, such as blade stacking, a one-dimensional radial stress equation accurately predicted area averaged Von Mises stress at the blade hub. With appropriate stacking, radial and Von Mises stresses were similar.

Emergency evacuation simulation of commercial aircraft

In order to receive certification approval for new products, aircraft manufacturers have to comply with the specifications regarding cabin evacuation. In case of real evacuation trials, agent-based simulation can be deployed, as they are a less cost-intensive mean of analysing passenger behaviour during the evacuation of commercial aircraft. This paper aims at examining the suitability of agent-based simulation software to reproduce passenger behaviour during evacuation processes. For this purpose, the algorithms and methods of the software PATHFINDER are introduced. Besides, the cabin of a single aisle aircraft is reconstructed in a high-density configuration using software-specific tools. A representative passenger distribution is implemented according to EASA regulations. Evacuation simulations for a single-aisle aircraft are conducted taking EASA standards into account. The effect of vital parameters such as walking speed, body dimension, conflict behaviour, collision response, acceleration time and exit allocation on evacuation times are examined. Results are discussed and examined for plausibility in order to determine whether evacuation simulations of commercial aircraft are possible using agent-based simulation software.

Modeling and Analysis of Customer Preference in Civil Aircraft Manufacturing Supervision

Customer manufacturing supervision of civil aircraft refers to the operator of the aircraft or its authorized entity’s supervision and inspection process during aircraft’s manufacturing and final assembly, through which the operator (airline company) ensures that the delivered aircrafts meet the requirements of approved technical standards, process specifications, and engineering documents, as well as confirming that optional components and aircraft’s layout comply with technical standards required by the purchase contract. Manufacturing supervision brings forward aircraft delivery inspection, qualitative improvement of which enables the improvement of efficiency in single aircraft airworthiness inspection, ensuring aircraft’s continued airworthiness. From the manufacture’s perspective, analyzing customer’s needs and preference on manufacture supervision in advance, taking advantage of the relatively long production cycle, disposing proper engineering solutions for manufacture deviations, reducing the business negotiation items due to deviations not only helps reach the goal of customer supervision, but also helps optimize engineering dispositions.

Multi-Attributes Decision-Making for CDO Trajectory Planning in a Novel Terminal Airspace

Continuous Descent Operations (CDO) has been recognized as an effective way to significantly reduce fuel burn and noise impact. Designing efficient and flexible arrival routes for generating conflict-free and economical trajectories is a cornerstone for fully achieving CDO by high-level automation in high-density traffic scenarios. In this research, inspired by the Point Merge (PM), we design the Inverted Crown-Shaped Arrival Airspace (ICSAA) and its operational procedures to support Omni-directional CDO. In order to generate optimal conflict-free trajectories for upcoming aircraft in an efficient manner, we established a multi-objective trajectory optimization model solved by Non-dominated Sorting Genetic Algorithm with Elitist Strategy (NSGA-II). The Pareto solutions of minimal fuel consumption and trip time were achieved in single aircraft and highly complex multi-aircraft scenarios. Among all the elements of Pareto front, we obtained an unique solution with Entropy-Weights Method and TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) to strike a better trade-off among collision probability, fuel consumption, and trip time, which incorporates both air traffic controller’s and pilot’s interests. The effectiveness of CDO performance improvement and computational efficiency in different scenarios were verified. The ICSAA would be a promising structure that promotes the application of automated and flexible CDO.

Electricity price for aviation

This paper dissertates about the importance of electricity price for the possible introduction of electric solutions in aviation. Electric motors start to play a significant role in plans for the decarbonization of air transport. In the field of single engine aircraft, there are first certified types and even legislation is changing to ease the introduction of electric planes. Contrary to the prices of oil-based fuels, electricity is less volatile but for the end consumer, there is an extreme price difference, based on the amount of electricity consumed annually. This fact shall be stressed and shall play a key role in any economic decision-making about the introduction of electricity into aviation. The goal of this paper is to help estimate future electricity annual consumption to predict for the user what the electricity price will be.

Manoeuvring control of an underactuated single rotor aircraft

Manoeuvring control of an underactuated single rotor aircraft

Manoeuvring control of an underactuated single rotor aircraft

Manoeuvring control of an underactuated single rotor aircraft

An efficient cost estimation framework for aerospace applications using Matlab/Simulink

The ability to estimate costs and process times at the early stage of a design phase is of great importance to the product development process, enabling selection of the most suitable design and manufacturing concepts. Therefore, herein an efficient framework is developed, utilising appropriate process and feature based cost modelling techniques in a MATLAB/SIMULINK environment. The sophisticated structure of the cost tool, using the drag and drop approach of predefined SIMULINK blocks, enables the rapid cost modelling of complex aerospace assemblies. The capabilities of the developed framework are demonstrated through analysis of a novel air-intake structure for single aisle aircraft.

Single commercial aircraft system value evaluation method based on requirements engineering and value driven design in a commercial aircraft preliminary design stage

Single commercial aircraft system value evaluation method based on requirements engineering and value driven design in a commercial aircraft preliminary design stage

From FAST to FAST-OAD: An open source framework for rapid Overall Aircraft Design

To face the increasing environmental footprint of commercial aviation, industrial and research efforts have been focusing on exploring unconventional configurations and new propulsion paradigms, mostly based on electric technology. Such explorations require Overall Aircraft Design that has to be performed in an integrated multidisciplinary design environment. Such design environments are often limited to multidisciplinary analysis, adapted for a single aircraft configuration or require an important effort to be mastered. FAST-OAD is a software program developed by ONERA and ISAE-SUPAERO for aircraft sizing analysis and optimization that aims at user friendliness and modularity. It is an aircraft sizing code based on multidisciplinary design optimization techniques and the point mass approach to estimate the required fuel and energy consumption for a given set of TLARs. This paper presents the motivations for moving from the original software program, called FAST, to the open source code FAST-OAD based on OpenMDAO.

The Contrail Mitigation Potential of Aircraft Formation Flight Derived from High-Resolution Simulations

Formation flight is one potential measure to increase the efficiency of aviation. Flying in the upwash region of an aircraft’s wake vortex field is aerodynamically advantageous. It saves fuel and concomitantly reduces the carbon foot print. However, CO2 emissions are only one contribution to the aviation climate impact among several others (contrails, emission of H2O and NOx). In this study, we employ an established large eddy simulation model with a fully coupled particle-based ice microphysics code and simulate the evolution of contrails that were produced behind formations of two aircraft. For a large set of atmospheric scenarios, these contrails are compared to contrails behind single aircraft. In general, contrails grow and spread by the uptake of atmospheric water vapour. When contrails are produced in close proximity (as in the formation scenario), they compete for the available water vapour and mutually inhibit their growth. The simulations demonstrate that the contrail ice mass and total extinction behind a two-aircraft formation are substantially smaller than for a corresponding case with two separate aircraft and contrails. Hence, this first study suggests that establishing formation flight may strongly reduce the contrail climate effect.

Augmented Reality for Immersive and Tactile Flight Simulation

Flight simulators based on wrap-around displays provide an immersive experience for pilot training, but not only are they expensive and bulky, they typically only simulate a single aircraft configuration. Virtual reality (VR) is an interesting alternative, providing an immersive experience with lower cost and space requirements, as well as the ability to simulate arbitrary aircraft. Unfortunately, current VR systems do not provide natural tactile interaction with instruments and avionics in the cockpit environment. This article explores augmented reality (AR) as an alternative to VR and wrap-around display flight simulators, delivering an immersive experience for pilot training and tactile interaction with aircraft controls. The concept is demonstrated through a basic general aviation simulator setup, showing that a relatively low-cost personal computer and graphics processing unit can provide AR simulations at useful frame rates.

Dynamic Topology Reconstruction Protocol for UAV Swarm Networking

Along with the fourth industrial revolution, the use of unmanned aerial vehicles (UAV) has grown very rapidly over the past decade. With this rapid growth, studies using UAVs are underway in various areas. UAVs are more economical and effective when utilizing several nodes rather than operating a single aircraft. In general, UAVs collect and transmit information to the control center (CC), and act on control commands from the CC. Communication between UAVs and the control center is usually achieved using modules such as radio frequency (RF), Bluetooth, Wireless Fidelity (Wi-Fi) and cellular. However, when multiple UAVs communicate directly with the CC, the limitations of communication technologies and problems with increasing nodes occur. To address these points, several studies have constructed an ad-hoc network of UAVs to address the limitations of Wi-Fi and Bluetooth communication range, or the high cost of cellular systems. However, previous studies have constructed fixed topology ad-hoc networks. These studies did not take into account the problem of changing network topology due to the rapid mobility and frequent formation changes of UAVs. Due to this, limits occurred such that UAVs moved only in the pre-built topology. In this paper, we propose a dynamic topology construction protocol for UAV swarms to address this problem. The main contents of this paper are as follows. We first look at the research and limitations of existing UAV communications, and propose a protocol to solve this problem. This paper proposes a protocol for UAV construction of ad-hoc networks when trying to perform missions using multiple UAVs, and also describes how the changed network topology is reconstructed when network topology changes due to changes in flight formation. Finally, we establish a situation and apply the proposed protocol, analyze the results and describe further required research.

A Design of Simulation Environment for Small Fixed-wing Aircraft

Multi-Agent Particle Environment (MPE) [1] proposed by OpenAI is applied to the study of multi-agent reinforcement learning strategies. However, the motion rules of the agent are excessively simplified. In order to make the environment more suitable to small fixed-wing aircraft, we have made following improvements: 1. The dynamic model of the agent in the MPE does not conform to the characteristics of the fixed-wing aircraft. In order to simulate the dynamic characteristics of the fixed-wing aircraft, a speed-related damping mechanism is introduced into the two-dimensional motion environment. 2. Since the MPE lacks the control module for single agent, the MPE cannot meet the challenges raised by single agent control. A two-layer controller is proposed which includes the outer layer (Total Energy Control System and L_1) and the inner layer (PID). 3. The MPE does not contain any decision module. In order to comprehensively study the collaborative decision-making behavior of aircrafts in target allocation, a swarm decision module is added to the environment. In addition, the concept of control period is introduced to reduce the gap between simulation and the actual situation. Finally, several simulations were carried out to test the improved Multi-Agent Aircraft Environment (MAE). The test cases include the outer layer with L1 and Total Energy Control System (TECS) algorithm in two dimensions, the PID inner layer control algorithm and the designed auction algorithm. The tests complete the process of single aircraft flight, Multiple aircrafts scan-search flight and Multiple aircrafts dynamical-waypoint flight, which verifies the effectiveness of MAE.

Localization of Life Safety Vests in an Aircraft Using Backscattering RFID Communication

In an aircraft, a variety of equipment are installed for the safety of the passengers, including seat belts, life vests, oxygen masks and cylinders, which require traceability for an efficient maintenance schedule. Furnishing them with RFID tags can enable the maintenance personnel to obtain accurate service history by just querying the tags. Overwater air travel mandates that the life vests should be present under each passenger seat before the aircraft is airborne. A mere count of life vests is insufficient as locating the seat that has a missing vest is required - a time consuming and non-trivial activity. We focus on 2D tracking of the life vests using backscattering RFID communication. Our study is limited to single aisle aircraft, although, it can be extended seamlessly to twin aisle wide body aircraft. A Divide-and-Conquer approach has been implemented, using COTS components, for locating the tags based on the phase measured from the signals backscattered by the tags. Extensive experiments are conducted by emulating the environment in an aircraft mockup fuselage. We experimented with two different setups, viz. , Standard Mobile Platform and Novel Handheld setups. Average percentage errors of 4.7% and 4.6% have been achieved with the Handheld setup in the x and y directions, respectively.

Probabilistic fault recoverability analysis of flight control process

Probabilistic Fault Recoverability (FR) property reveals the capability of a system to accommodate faults under admissible input energy constraints in the sense of satisfactory probability. Motivated by the idea of probabilistic control methods, a class of admissible probability density functions is designed for detailed description of fault parameters, under which several probabilistic FR conditions are established. This significantly enlarges the range of recoverable faults obtained from the deterministic FR analysis. The tradeoffs between the risk of performance degradation and this increased recoverability margin are exactly achieved by allowing a small risk of FR violation. This paper analyzes the probability FR of dynamic systems with switching and interconnection characteristics, and applies the new results to several aircraft models including single longitudinal aircraft dynamic, Highly Maneuverable Technology (HiMAT) vehicle and meta aircraft. Simulation results show the efficiency of the proposed methods based on the comparison between deterministic and probabilistic cases.