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Eyes-out airborne object detector for pilots situational awareness
Get PDFWith the exponential development of new flying objects, pilots need to pay even more attention to evaluate their environment, make decisions, and fly safely. Such situation awareness (SA) has multiple codified rules to guarantee the safety of pilots. This paper analyses the feasibility of a portable perception augmentation module (PAM) to help pilots improve their situational awareness based on two key actions on long-distance airborne objects, namely, object detection and distance and trajectory estimation. The developed object detection pipeline based on the state-of-the-art (SOTA) YOLOv8 architecture achieves high accuracy with a mAP50 of 0.835 for objects up to 3000 meters. The inference of the system is 1 second for a 360° scan of the aeroplane surroundings thanks to 4 wide FOV high-resolution cameras. The data used for the model is generated by Airsim in a completely automatized process. The potential implementation of stereo vision and the influence to the PAM are also evaluated. All of these tests are also performed on additional real-life data to evaluate generalization performances, which also show satisfactory results. Efforts in the development of the PAM were made to find the best balance between various constraints such as weight, energy consumption, and accuracy. Characteristic analysis of the PAM such as weight, energy consumption, and accuracy are proposed to seek the optimal balance between various real-world constraints. Real hardware considerations are made to estimate the hardware cost of the PAM based on the simulated results in this study. With further improvement in the trajectory estimation and model generalization, a prototype could be made, deployed, and sold to recreational pilots for safer flights. The code and data are available on: https://github.com/Alcharyx/IRP-Eye-out/We would like to thank Haydn Thompson from THHINK Ltd our industrial partner during this project for his support and creative feedback along this project. We would like to express our sincere gratitude to Cranfield University who gave us access to Crescent2 supercomputer facilities during this research.2024 IEEE Aerospace Conferenc
Path-tracking control at the limits of handling of a prototype over-actuated autonomous vehicle
Get PDFConsidering the vehicle dynamics at the limits of handling is vital to improve the performance and safety of autonomous vehicles especially in extreme situations. This paper presents the development of a path-tracking controller for an over-actuated autonomous vehicle. The vehicle is an electric prototype equipped with torque vectoring and four-wheel steering, which enable enhanced control of vehicle dynamics. A model predictive controller is proposed taking into account the nonlinearities in vehicle dynamics at the limits of handling as well as the crucial actuator constraints. The controller is examined in both high-fidelity simulation and practical testing to validate the vehicle's handling performance. Both the simulation and testing results illustrate that the over-actuation topology can enhance the handling performance as well as vehicle stability at conditions close to the limits of handling. With additional references such as side slip angle, the vehicle's attitude under such extreme condition can also be manipulated. The testing also demonstrates the real-time capability of the controller. Further testing has been done to confirm that side slip angle reference plays an important role in path-tracking control at the limits of handling, and to push the vehicle to the friction limits.This work is supported by Innovate UK under the AID-CAV project (project reference 104277).Vehicle System Dynamic
A comparative experimental study on the hydrodynamic performance of two floating solar structures with a breakwater in waves
Get PDFFloating Photovoltaic (FPV) is considered as a highly promising clean energy solution. In recent years, FPV has been widely deployed in calm water around the world. However, to find available space for further expansion, FPV needs to be deployed in seas whilst the oceanic waves significantly influence the structural stability and energy performance. On one hand, wave loads may cause structural fatigue and damage. On the other hand, wave-induced rotations of a floating solar panel will vary its tilt angle to the sunlight and thus affect the power output. To explore the new research field of ocean-based FPV, this work first designed a novel catamaran FPV floater with a four-point mooring system. Comparative experiments were then conducted in a wave tank to compare its seakeeping ability with a conventional flat-plate floater. Besides, a breakwater structure was further introduced to enhance the stability of these two types of floaters. Detailed data on floater motions and mooring line forces were collected under monochromatic wave conditions. Extensive analysis was performed to evaluate the wave-mitigating performance of the breakwater, as well as the nonlinearity in the motion and force time histories. Overall, the work provides valuable experimental data and novel insights into the design of FPV floaters and breakwater protection, supporting long-term sustainability of FPV on the ocean.L.H. acknowledges grants received from Innovate UK, United Kingdom (No. 10048187, 10079774, 10081314), the Royal Society, United Kingdom (IEC NSFC 223253, RG R2 232462) and UK Department for Transport (TRIG2023 - No. 30066).Solar Energ
Developing a framework leveraging building information modelling to validate fire emergency evacuation
Get PDFIn fire emergency management, a delayed execution will cause a significant number of casualties. Conventional fire drills typically only identify a certain percentage of evacuation bottlenecks after the building has been constructed, which is hard to improve. This paper proposes an innovative framework to validate fire emergency evacuation at the early design stage. According to the experience and knowledge of fire emergency evacuation design, the proposed framework also introduces a seamless two-way information channel to embed fire emergency evacuation simulations into a BIM-based design environment. Several critical factors for fire evacuation have been reviewed in relevant domain knowledge, which is used to build virtual characters to test in experimental scenarios. The results are analyzed to validate fire emergency evacuation factors, and the feedback knowledge is stored as a knowledge model for further applications.Building
Framework for multi-fidelity assessment of open rotor propeller aeroacoustics
Get PDFAerodynamically generated noise from open rotor aircraft has received immense research interests. Multi-fidelity numerical approaches are in demand for evaluating open rotor propeller noise without compromising computational accuracy and reducing cost. In this paper, propeller noise modelling methods at different fidelity levels are assessed by application to an aircraft propeller configuration at an advance ratio of 0.485 together with tip Reynolds and Mach numbers of 3.7×10^5 and 0.231, respectively. The flow solution of the propeller is obtained using coarse-grid Large Eddy Simulation and then inputted into three acoustic solvers. At higher-fidelity level, Ffowcs-Williams and Hawkings analogy method is employed. Hanson’s method and Gutin’s method are applied at the medium- and lower -fidelity levels, respectively. Results from the three models are compared correlatively, as well as against existing experimental measurement data. Through the assessment, insight is given into future development of a multi-fidelity model for low-emission open rotor aircraft design. The presented multi-fidelity framework is being developed as part of the Innovate UK, Aerospace Technology Institute (ATI) funded research project – ONEheart (Out of Cycle NExt generation highly efficient air transport).The research leading to these results has received funding from the Innovate UK, Aerospace Technology Institute(ATI) in the UK, under the Out of Cycle NExt generation highly efficient air transport (ONEheart) project (Ref no.10003388). The first and fifth authors gratefully acknowledge the ‘SilentProp’ project, sponsored and supported by Horizon 2020 research and innovation programme under grant agreement number 882842.30th AIAA/CEAS Aeroacoustics Conference 202
Stress, strain, or energy? Which one is superior predictor of fatigue life in notched components? A novel machine learning-based framework
Get PDFThis paper introduces an efficient framework for accurately predicting the fatigue lifetime of notched components under uniaxial loading within the high-cycle fatigue regime. For this purpose, various machine learning algorithms are applied to a wide range of materials, loading conditions, notch geometries, and fatigue lives. Traditional approaches for this task have mostly relied on one of the mechanical response parameters, such as stress, strain, or energy. This study also concludes which of these parameters serves as a better measure. The key idea of the framework is to use the profile (field distribution represented by some points) of the mechanical response parameters (stress, strain, and energy release rate) to distinguish between different notch geometries. To demonstrate the accuracy and broad applicability of the framework, it is initially validated using metal materials, subsequently applied to specimens produced through additive manufacturing techniques, and ultimately tested on carbon fiber laminated composites. This research demonstrates the effective use of all three parameters in estimating fatigue lifetime, while stress-based predictions exhibit the highest accuracy. Among the machine learning algorithms investigated, Gradient Boosting and Random Forest yield the most successful results. A noteworthy finding is the significant improvement in prediction accuracy achieved by incorporating new data generated based on the Basquin equation.European CommissionEngineering Fracture Mechanic
The evolution of flexible working patterns
No full textFlexibility in organisations has emerged as a dominant discourse in recent decades, spawning multiple forms of new working arrangements loosely grouped under the term flexible working. This chapter is concerned with examining these various working arrangements. It looks first at their emergence and the factors that have influenced their development and growth. The discussion then moves to explore the evidence in relation to the outcomes of these working arrangements for individual workers and assesses more generally the consequences of these developments. Importantly, the use of some of these arrangements, most notably remote working, has been shaped in a major way by experiences during the Covid-19 pandemic. This will be considered and the implications for future working patterns discussed.Work, Employment and Flexibilit
Classification of RF transmitters in the presence of multipath effects using CNN-LSTM
Get PDFRadio frequency (RF) communication systems are the backbone of many intelligent transport and aerospace operations, ensuring safety, connectivity, and efficiency. Accurate classification of RF transmitters is vital to achieve safe and reliable functioning in various operational contexts. One challenge in RF classification lies in data drifting, which is particularly prevalent due to atmospheric and multipath effects. This paper provides a convolutional neural network based long short-term memory (CNN-LSTM) framework to classify the RF emitters in drift environments. We first simulate popular-used RF transmitters and capture the RF signatures, while considering both power amplifier dynamic imperfections and the multipath effects through wireless channel models for data drifting. To mitigate data drift, we extract the scattering coefficient and approximate entropy, and incorpo-rate them with the in-phase quadrature (I/Q) signals as the input to the CNN-LSTM classifier. This adaptive approach enables the model to adjust to environmental variations, ensuring sustained accuracy. Simulation results show the accuracy performance of the proposed CNN-LSTM classifier, which achieves an overall 91.11% in the presence of different multipath effects, bolstering the resilience and precision of realistic classification systems over state of the art ensemble voting approaches.Engineering and Physical Sciences Research CouncilThis work has been supported by the Engineering and Physical Sciences Research Council Trustworthy Autonomous Systems Security Node (EP/V026763/1), EPSRC CHED-DAR: Communications Hub For Empowering Distributed ClouD Computing Applications And Research (EP/X040518/1, EP/Y037421/1), and GE Aerospace.2024 IEEE International Conference on Communications Workshops (ICC Workshops
Integration of renewable energy sources in tandem with electrolysis: a technology review for green hydrogen production
Get PDFThe global shift toward sustainable energy solutions emphasises the urgent need to harness renewable sources for green hydrogen production, presenting a critical opportunity in the transition to a low-carbon economy. Despite its potential, integrating renewable energy with electrolysis to produce green hydrogen faces significant technological and economic challenges, particularly in achieving high efficiency and cost-effectiveness at scale. This review systematically examines the latest advancements in electrolysis technologies—alkaline, proton exchange membrane electrolysis cell (PEMEC), and solid oxide—and explores innovative grid integration and energy storage solutions that enhance the viability of green hydrogen. The study reveals enhanced performance metrics in electrolysis processes and identifies critical factors that influence the operational efficiency and sustainability of green hydrogen production. Key findings demonstrate the potential for substantial reductions in the cost and energy requirements of hydrogen production by optimising electrolyser design and operation. The insights from this research provide a foundational strategy for scaling up green hydrogen as a sustainable energy carrier, contributing to global efforts to reduce greenhouse gas emissions and advance toward carbon neutrality. The integration of these technologies could revolutionise energy systems worldwide, aligning with policy frameworks and market dynamics to foster broader adoption of green hydrogen.International Journal of Hydrogen Energ
Exploring the determinants of career success after expatriation: a focus on job fit, career adaptability, and expatriate type
Get PDFExpatriation significantly influences the career paths of individuals after their international work experience. This study draws on person-environment fit and career construction theories to examine the role of job fit, career adaptability, and expatriate type in shaping both objective and subjective career success. Our 2020 sample comprised 191 expatriates who had worked abroad four to five years prior. This group included both self-initiated and assigned expatriates, as well as repatriates and re-expatriates, providing a broader scope than is typical in expatriation studies. The research reveals that job fit, career adaptability, and expatriate type substantially affect career outcomes. It also identifies that the type of expatriate moderates the relationship between career adaptability and objective career success. Our work extends the applicability of person-environment fit theory and career construction theory within the complex landscape of expatriate careers. The investigation not only deepens our understanding of the factors driving career success post-expatriation but also provides valuable insights to aid the effective management of international careers