Quantification and Prediction of Pilot Workload in the Helicopter/Ship Dynamic Interface

Author(s):  
R Bradley ◽  
C A Macdonald ◽  
T W Buggy

The evaluation, early in the design cycle, of the limits for operating aircraft from ships in a wide range of sea states and atmospheric conditions has become an important issue for two main reasons. First, the simultaneous entry into service of new helicopter types and new naval platforms has generated an enormous task in the development of appropriate Ship Helicopter Operating Limits for in-service operations. Second, it has become clear that such operational factors need to be addressed at the design stage - which of necessity involves developing a predictive capacity in all of the areas which influence operational capability. These considerations need to take place in the context of technological advances which seek to assist the pilot in operations from ships. Improved radar for ship approaches and enhanced cueing, located around hangars and landing spots, are both areas which are being continually developed in association with upgraded aircraft systems for guidance, control, and stability augmentation. Ultimately, however, the situation comes down to the pilot's assessment of the workload involved in any task and the handling qualities of the vehicle being controlled. For this reason there has been a growing interest in two related areas: (i) the development of metrics to provide a consistent indicator of pilot workload and (ii) the enhancement of existing pilot models to generate authentic control activity in the aircraft/ship dynamic interface. This article describes recent techniques for extracting workload metrics from control activity and indicates the extent to which acceptably accurate workload predictions can be made. Some advances in pilot modelling are also described and examples are given to demonstrate the capability and limitations of currently available methods. Finally, the present state of integration of the two aspects into a robust tool for ship and aircraft system design is discussed. The focus of this article is, of necessity, on helicopter operations because that is where most of the current work has been centred.

Author(s):  
S. Jennings ◽  
G. Craig ◽  
Stephan Carignan ◽  
Kris Ellis ◽  
D. Thorndycraft Qinetiq

This paper describes an investigation of a workload measurement technique based on pilot control movements. The Dynamic Interface Modeling and Simulation System Product Metric (DIMSS PM) assumes that pilot control activity can be used to evaluate pilot workload. Three qualified test pilots flew the fly-bywire NRC Bell 205 helicopter in a short test program that compared the DIMSS PM with subjective workload ratings and handling qualities ratings. The pilots performed a variation of an ADS-33E bob-up with varying levels of simulated turbulence and modified cyclic control characteristics. Good agreement was found for most in-flight test conditions between DIMSS Workload Metric scores and subjective workload ratings from the Bedford Workload Scale and Cooper-Harper handling qualities ratings. While, the DIMSS Workload Metric did not accurately reflect workload increases due to variations in the cyclic stick characteristics, the metric shows promise as an objective measurement tool of pilot workload in well-defined tests.


Author(s):  
Andrea Zanoni ◽  
Luca Conti ◽  
Pierangelo Masarati

In the context of a modern approach to the design of rotocraft, handling qualities should be the result of careful planning, rather than the output of a multitude of other choices, made primarily focusing on more immediate constraints. For a wide range of flight conditions and mission task elements, the test pilot feedback is the essential measure upon which the design choices are made. Thus, it is becoming of fundamental importance to be able to simulate a representative model of the vehicle in a pilot-in-the-loop environment as early as possible in the design stage. This work is intended to document the development process of one such system currently being realized at the facilities belonging to the Aerospace Science and Technology Department of Politecnico di Milano. Particular attention is given to the software architecture, based on the free and open-source multibody solver MBDyn. The development of a module specifically designed to exploit the environment visualization capabilities of FlightGear, also a free and open-source software, is presented.


2017 ◽  
Vol 121 (1246) ◽  
pp. 1833-1857 ◽  
Author(s):  
I. Owen ◽  
M. D. White ◽  
G. D. Padfield ◽  
S. J. Hodge

ABSTRACTThis paper reviews some of the research that has been carried out at the University of Liverpool where the Flight Science and Technology Research Group has developed its Heliflight-R full-motion research simulator to create a simulation environment for the launch and recovery of maritime helicopters to ships. HELIFLIGHT-R has been used to conduct flight trials to produce simulated Ship-Helicopter Operating Limits (SHOLs). This virtual engineering approach has led to a much greater understanding of how the dynamic interface between the ship and the helicopter contributes to the pilot's workload and the aircraft's handling qualities and will inform the conduct of future real-world SHOL trials. The paper also describes how modelling and simulation has been applied to the design of a ship's superstructure to improve the aerodynamic flow field in which the helicopter has to operate. The superstructure aerodynamics also affects the placement of the ship's anemometers and the dispersion of the ship's hot exhaust gases, both of which affect the operational envelope of the helicopter, and both of which can be investigated through simulation.


2021 ◽  
pp. 1-35
Author(s):  
W.A. Memon ◽  
M.D. White ◽  
G.D. Padfield ◽  
N. Cameron ◽  
L. Lu

Abstract The research reported in this paper is aimed at the development of a metric to quantify and predict the extent of pilot control compensation required to fly a wide range of mission task elements. To do this, the utility of a range of time- and frequency-domain measures to examine pilot control activity whilst flying hover/low-speed and forward flight tasks are explored. The tasks were performed by two test pilots using both the National Research Council (Canada)’s Bell 412 Advanced Systems Research Aircraft and the University of Liverpool’s HELIFLIGHT-R simulator. Handling qualities ratings were awarded for each of the tasks and compared with a newly developed weighted adaptive control compensation metric based on discrete pilot inputs, showing good correlation. Moreover, in combination with a time-varying frequency-domain exposure, the proposed metric is shown to be useful for understanding the relationship between the pilot’s subjective assessment, measured control activity and task performance. By collating the results from the subjective and objective metrics for a range of different mission task elements, compensation boundaries are proposed to predict and verify the subjective assessments from the Cooper-Harper Handling Qualities Rating scale.


Author(s):  
Michele Righi ◽  
Giacomo Moretti ◽  
David Forehand ◽  
Lorenzo Agostini ◽  
Rocco Vertechy ◽  
...  

AbstractDielectric elastomer generators (DEGs) are a promising option for the implementation of affordable and reliable sea wave energy converters (WECs), as they show considerable promise in replacing expensive and inefficient power take-off systems with cheap direct-drive generators. This paper introduces a concept of a pressure differential wave energy converter, equipped with a DEG power take-off operating in direct contact with sea water. The device consists of a closed submerged air chamber, with a fluid-directing duct and a deformable DEG power take-off mounted on its top surface. The DEG is cyclically deformed by wave-induced pressure, thus acting both as the power take-off and as a deformable interface with the waves. This layout allows the partial balancing of the stiffness due to the DEG’s elasticity with the negative hydrostatic stiffness contribution associated with the displacement of the water column on top of the DEG. This feature makes it possible to design devices in which the DEG exhibits large deformations over a wide range of excitation frequencies, potentially achieving large power capture in a wide range of sea states. We propose a modelling approach for the system that relies on potential-flow theory and electroelasticity theory. This model makes it possible to predict the system dynamic response in different operational conditions and it is computationally efficient to perform iterative and repeated simulations, which are required at the design stage of a new WEC. We performed tests on a small-scale prototype in a wave tank with the aim of investigating the fluid–structure interaction between the DEG membrane and the waves in dynamical conditions and validating the numerical model. The experimental results proved that the device exhibits large deformations of the DEG power take-off over a broad range of monochromatic and panchromatic sea states. The proposed model demonstrates good agreement with the experimental data, hence proving its suitability and effectiveness as a design and prediction tool.


Author(s):  
I Bridle ◽  
S R Woodhead

Degradation of bulk solid product during pneumatic conveying is of concern in a range of process industries. However, prediction of product degradation levels at the conveyor design stage has proved challenging. This paper presents a proposed prediction technique, based on the use of a pilot-sized test facility to provide relevant empirical data. The results of experiments undertaken using malted barley, basmati rice, and granulated sugar are reported. For each bulk solid material, a wide range of conveying conditions have been examined, consistent with common industrial practice. Correlations between predictions and experimental data obtained in an industrial-scale conveyor are presented and discussed.


Author(s):  
Dominik Ebi ◽  
Peter Jansohn

Abstract Operating stationary gas turbines on hydrogen-rich fuels offers a pathway to significantly reduce greenhouse gas emissions in the power generation sector. A key challenge in the design of lean-premixed burners, which are flexible in terms of the amount of hydrogen in the fuel across a wide range and still adhere to the required emissions levels, is to prevent flame flashback. However, systematic investigations on flashback at gas turbine relevant conditions to support combustor development are sparse. The current work addresses the need for an improved understanding with an experimental study on boundary layer flashback in a generic swirl burner up to 7.5 bar and 300° C preheat temperature. Methane-hydrogen-air flames with 50 to 85% hydrogen by volume were investigated. High-speed imaging was applied to reveal the flame propagation pathway during flashback events. Flashback limits are reported in terms of the equivalence ratio for a given pressure, preheat temperature, bulk flow velocity and hydrogen content. The wall temperature of the center body along which the flame propagated during flashback events has been controlled by an oil heating/cooling system. This way, the effect any of the control parameters, e.g. pressure, had on the flashback limit was de-coupled from the otherwise inherently associated change in heat load on the wall and thus change in wall temperature. The results show that the preheat temperature has a weaker effect on the flashback propensity than expected. Increasing the pressure from atmospheric conditions to 2.5 bar strongly increases the flashback risk, but hardly affects the flashback limit beyond 2.5 bar.


2021 ◽  
Author(s):  
James Harding

<p>Earth Observation (EO) satellites are drawing considerable attention in areas of water resource management, given their potential to provide unprecedented information on the condition of aquatic ecosystems. Despite ocean colours long history; water quality parameter retrievals from shallow and inland waters remains a complex undertaking. Consistent, cross-mission retrievals of the primary optical parameters using state-of-the-art algorithms are limited by the added optical complexity of these waters. Less work has acknowledged their non- or weakly optical parameter counterparts. These can be more informative than their vivid counterparts, their potential covariance would be regionally specific. Here, we introduce a multi-input, multi-output Mixture Density Network (MDN), that largely outperforms existing algorithms when applied across different bio-optical regimes in shallow and inland water bodies. The model is trained and validated using a sizeable historical database in excess of 1,000,000 samples across 38 optical and non-optical parameters, spanning 20 years across 500 surface waters in Scotland. The single network learns to predict concurrently Chlorophyll-a, Colour, Turbidity, pH, Calcium, Total Phosphorous, Total Organic Carbon, Temperature, Dissolved Oxygen and Suspended Solids from real Landsat 7, Landsat 8, and Sentinel 2 spectra. The MDN is found to fully preserve the covariances of the optical and non-optical parameters, while known one-to-many mappings within the non-optical parameters are retained. Initial performance evaluations suggest significant improvements in Chl-a retrievals from existing state-of-the-art algorithms. MDNs characteristically provide a means of quantifying the noise variance around a prediction for a given input, now pertaining to real data under a wide range of atmospheric conditions. We find this to be informative for example in detecting outlier pixels such as clouds, and may similarly be used to guide or inform future work in academic or industrial contexts. </p>


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Majid Amirfakhrian ◽  
Mahboub Parhizkar

AbstractIn the next decade, machine vision technology will have an enormous impact on industrial works because of the latest technological advances in this field. These advances are so significant that the use of this technology is now essential. Machine vision is the process of using a wide range of technologies and methods in providing automated inspections in an industrial setting based on imaging, process control, and robot guidance. One of the applications of machine vision is to diagnose traffic accidents. Moreover, car vision is utilized for detecting the amount of damage to vehicles during traffic accidents. In this article, using image processing and machine learning techniques, a new method is presented to improve the accuracy of detecting damaged areas in traffic accidents. Evaluating the proposed method and comparing it with previous works showed that the proposed method is more accurate in identifying damaged areas and it has a shorter execution time.


2017 ◽  
Vol 25 (2) ◽  
pp. 207
Author(s):  
Eros Rosilah Rosilah

Learning Social Studies (IPS) is a compulsory subject taught. Learning IPS has a very wide range of material. Reality on the ground results of test scores of fourth grade students of SDN Babakan Tarogong 5 in social studies subject of natural resources, economic activity and technological advances in the district / city and province is still very low. This is due to social studies learning not meet minimum completeness, because the strategy used so far have not matched the learning process. The purpose of this study to determine the activities of students in participating in learning by using learning strategies of problem solving. The results of this research has reached the average value of the class.Keyword : Natural resources, economic activities, technological progress.


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