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Use of augmented reality for hybrid mock-up validation in aviation maintainability
Get PDFTo perform maintainability and Human Factors assessment in preliminary aircraft architecture and design review, the simulation of maintenance activities is deployed inside industry. The use of augmented reality associated to a physical mock-up could be an alternative to other complementarity simulations already existing (virtual reality, physical mock-up alone). This paper introduces the first experimentation with this hybrid simulation and the results of its performance. This hybrid solution allows a reduced lead time in the development and decision process. It reduces the cost of the mock-up using only the basic shape of the model and tangible interfaces for the user. Augmented Reality increases the detail of the model and allows multiple configuration review and fosters collaboration between designers and project stakeholders
Experimental and numerical study of parallel blade-vortex interaction
Get PDFParallel Blade-Vortex Interaction is studied both via experimental wind-tunnel tests with wing models in a tandem setup and via LES simulations. A p-adaptive Local Discontinuous Galerkin approach is used, with a physically based refinement indicator and a dynamic anisotropic eddy viscosity model for subgrid scale turbulent stresses. The results validate the numerical tool and show its efficacy and efficiency in the simulation of BVI, succesfully extending the range of investigation of the experimental setup
Analysis of flight control and trajectory planning for autonomous ship landing using small-scale UAVS
Get PDFDue to the potential to expand flight envelopes and increase flight safety for sea based rotorcraft, there has been a drive to produce reliable autonomous ship landing algorithms. These algorithms are inherently complex and must be validated by extensive experimentation. Experimentation at model scale offers a controllable test bed that can be used to isolate the effects of individual parameter variations, helping gain insight into the limitations and vulnerabilities of a complex landing algorithm. In this paper, the development of an autonomous landing control mode suitable for use in scaled experiments of this nature is presented. The main goal in algorithm design was to create a landing solution representative of other methods published in the literature, while also allowing for easy variation of parameters during testing. The resulting algorithm features explicit model following controllers, quadratic programming trajectory generation, and deck motion prediction based on autoregressive models. Additionally, a scaling method based on Froude scaling is proposed and results from 230 scaled flight tests to a virtual deck are discussed. During testing, reference tracking bandwidths and jerk limitations were progressively reduced and deck prediction accuracy was degraded. Results show that the landing algorithm performs well for scaled moderate to high sea states and deck motion predictions help compensate for reduced aircraft mobility. It was also found that reduced tracking bandwidths effect landing accuracy, but that inclusion of reasonable jerk limitations can be important to prevent the autonomy algorithm from overcompensating for artificially reduced model scale bandwidths
Numerical investigation and design exploration on aerodynamic performance for stacked rotor
No full textA coaxial co-rotating (stacked) rotor can produce an improved aerodynamic efficiency compared to a coaxial counter-rotating rotor and a single-rotor with the same solidity. Since the aerodynamic performance of the stacked rotor highly depends on the relative positions of tip vortices and rotor blades, design parameters such as vertical spacing, phase angle, and pitch angle should be optimized for an operational condition. In this study, a numerical analysis through a high-order accurate Reynolds-Averaged Navier-Stokes solver was carried out to analyze the flowfields of stacked rotor configurations in a hovering condition. Design points were selected using the full factorial method with three design parameters. Exploring the wide design space revealed the full extent of performance that can be achieved through stacked rotor adjustment. The inflow and wake interference effects were turned out to be dominant factors in the aerodynamic performance of the stacked rotor system. The corresponding sectional thrust and power of each design point were modeled using a neural network. Finally, design exploration and optimization were conducted for aerodynamic efficiency
HUMS proactive analysis for predictive maintenance
No full textAs part of maintenance improvement on helicopters, Airbus Helicopters has made available to customers, since 2018, a proactive analysis service based on Health and Usage Monitoring System data generated during the flight. Thanks to the use of various algorithms, capable of detecting changes in behavior as well as any incipient degradation, Airbus Helicopters provides customers, in the form of periodic reports, anticipated maintenance recommendations. These analyses, which today use all the different sources of data (vibrations, flight parameters, failure codes), are a first step towards the reduction of unscheduled events and predictive maintenance. This paper will present in details two algorithms “BEHAVIOR CHANGE RECOGNITION” and “PATTERN RECOGNITION
Impact of differential torsional rotor cant on the flight characteristics of a passenger-grade quadrotor
Get PDFAt the Institute of Flight Systems at DLR, studies have been performed to understand the flight characteristics of novel eVTOL configurations. As part of these studies, previously conducted handling qualities assessments on a 2-passenger quadrotor configuration had revealed major deficiencies about its yaw axis. Based on this result, the quadrotor model has been modified by differential torsional canting to improve its yaw characteristics. This paper analyzes the resulting impacts of such modification on the flight performance, dynamic stability and handling qualities. A piloted virtual flight test campaign was conducted to assess predicted and assigned handling qualities levels in compliance with the quantitative and qualitative performance standards of ADS-33E. The results show an improvement in midterm yaw response at the expense of increase in total required power. The pilot ratings and comments also confirm the improvement on the yaw response upon the flown MTEs
Retrofitting an existing helicopter with eVTOL capabilities: challenges and opportunities
Get PDFOver the past decade, considerable work has also been done on the design, development, and deployment of eVTOL vehicles for civilian and military use. Relatively less work has been done on retrofitting existing helicopters with eVTOL capabilities. Keeping the existing airframe while implementing changes to the structural elements, rotors, and other components such as engines and drive train presents a significant challenge. For commercial helicopters, the cost and gross weight of the system, and the impact of design changes on the performance of the vehicle must also be addressed. In this study, we examine the environmental impact of retrofitting notional helicopter configurations based on the highly successful MBB Bo 105 helicopter, and its successor, the EC 135 helicopter. The advances include an improved rotor, fuselage drag reduction technologies, and an allelectric system. Results are presented for the impact of these modifications on the system weight, range, and endurance. The paper also discusses challenges and opportunities associated with these design modifications
Assessing helicopter recovery to an offshore platform using piloted flight simulation and time-accurate airwakes
No full textThis paper describes an investigation in which piloted flight simulation has been used to study the effect of turbulent air flow on helicopter recovery to an offshore platform. A helicopter flight simulation environment has been developed in which the unsteady air flow over a full-scale offshore platform has been modelled using time-accurate Computational Fluid Dynamics. Real-time piloted helideck landings have been conducted in a six-degree-of-freedom motion flight simulator where a flight dynamics model representative of a Sikorsky SH-60B Seahawk helicopter was integrated with 30 seconds of unsteady computed air flow. A test pilot was instructed to perform landings to the helideck of the platform for wind speeds of 20 to 50 kt. Ratings of pilot workload and turbulence were obtained during the trial which, along with the recorded pilot control inputs and helicopter states, were used to analyse the effect of the platform’s airwake on the helicopter and on pilot workload. The results show that as the freestream wind speed increased, the turbulence intensity and pilot workload also increased. The workload ratings, along with the corresponding pilot control activity and helicopter positional accuracy, are discussed in relation to the airwake to which the helicopter was subjected. The paper demonstrates how flight simulation with time-accurate airwakes could be used to support helicopter operations to offshore platforms
Path planning for innovative solutions based on UAV-helicopter cooperation in HEMS missions
Get PDFThe paper investigates the path-planning problem applied to an innovative UAV–helicopter cooperation system that aims at increasing safety during HEMS operations. The drone, that could be optionally launched by the helicopter, will have the mission to explore the area of operation to detect meteorological and physical obstacles. The combination of Rapidly-exploring Random Tree? as global planner and of Bidirectional Rapidly-exploring Random Tree as local planner is proved to provide a nearly-optimal global path and a rapid re-planning in case of new obstacles detection. The adoption of Savitzky–Golay filter enables trajectory smoothing, improving its practicability. The feasibility of the identified trajectory for a three-dimensional helicopter is assessed through computation of attitude and forces, the latter carried out by means of a multibody analysis softwar