Pub Date : 2021-04-02DOI: 10.3846/AVIATION.2021.13420
A. Faghihinia, A. Atashgah, M. Dehghan
In this paper, the propagation of uncertainty in a cooperative navigation algorithm (CNA) for a group of flying robots (FRs) is investigated. Each FR is equipped with an inertial measurement unit (IMU) and range-bearing sensors to measure the relative distance and bearing angles between the agents. In this regard, an extended Kalman filter (EKF) is implemented to estimate the position and rotation angles of all the agents. For further studies, a relaxed analytical performance index through a closed-form solution is derived. Moreover, the effects of the sensors noise covariance and the number of FRs on the growth rate of the position error covariance is investigated. Analytically, it is shown that the covariance of position error in the vehicles equipped with the IMU is proportional to the cube of time. However, the growth rate of the navigation error is, considerably more rapid compared to a mobile robot group. Furthermore, the covariance of position error is independent of the path and noise resulting from the relative position measurements. Further, it merely depends on both the size of the group and noise characteristics of the accelerometers. Lastly, the analytical results are validated through comprehensive Guidance, Navigation, and Control (GNC) in-the-loop simulations.
{"title":"ANALYTICAL EXPRESSION FOR UNCERTAINTY PROPAGATION OF AERIAL COOPERATIVE NAVIGATION","authors":"A. Faghihinia, A. Atashgah, M. Dehghan","doi":"10.3846/AVIATION.2021.13420","DOIUrl":"https://doi.org/10.3846/AVIATION.2021.13420","url":null,"abstract":"In this paper, the propagation of uncertainty in a cooperative navigation algorithm (CNA) for a group of flying robots (FRs) is investigated. Each FR is equipped with an inertial measurement unit (IMU) and range-bearing sensors to measure the relative distance and bearing angles between the agents. In this regard, an extended Kalman filter (EKF) is implemented to estimate the position and rotation angles of all the agents. For further studies, a relaxed analytical performance index through a closed-form solution is derived. Moreover, the effects of the sensors noise covariance and the number of FRs on the growth rate of the position error covariance is investigated. Analytically, it is shown that the covariance of position error in the vehicles equipped with the IMU is proportional to the cube of time. However, the growth rate of the navigation error is, considerably more rapid compared to a mobile robot group. Furthermore, the covariance of position error is independent of the path and noise resulting from the relative position measurements. Further, it merely depends on both the size of the group and noise characteristics of the accelerometers. Lastly, the analytical results are validated through comprehensive Guidance, Navigation, and Control (GNC) in-the-loop simulations.","PeriodicalId":51910,"journal":{"name":"Aviation","volume":"25 1","pages":"10-21"},"PeriodicalIF":1.0,"publicationDate":"2021-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42786616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-01DOI: 10.3846/AVIATION.2021.12327
A. Kornev, S. Stetsenko, V. Yatsenko, A. Smolyakov, D. Kalinichenko
The analytical and experimental studies of the aircraft’s supersonic air intakes have been carried out. An integrated approach to the gas-dynamic designing of aircraft’s supersonic air intakes that eliminates the scale effect problem of a wind tunnel with a small-sized testing area is proposed. The designing approach accelerates the development process and reduces the resource intensity due to the rational distribution of tasks between numerical and physical experiments. The results of the unique tests of the scaled ramjet’s air intake physical model in the supersonic wind tunnel are presented.
{"title":"INTEGRATED APPROACH TO GAS-DYNAMIC DESIGNING OF SUPERSONIC AIR INTAKES OF AIRCRAFT","authors":"A. Kornev, S. Stetsenko, V. Yatsenko, A. Smolyakov, D. Kalinichenko","doi":"10.3846/AVIATION.2021.12327","DOIUrl":"https://doi.org/10.3846/AVIATION.2021.12327","url":null,"abstract":"The analytical and experimental studies of the aircraft’s supersonic air intakes have been carried out. An integrated approach to the gas-dynamic designing of aircraft’s supersonic air intakes that eliminates the scale effect problem of a wind tunnel with a small-sized testing area is proposed. The designing approach accelerates the development process and reduces the resource intensity due to the rational distribution of tasks between numerical and physical experiments. The results of the unique tests of the scaled ramjet’s air intake physical model in the supersonic wind tunnel are presented.","PeriodicalId":51910,"journal":{"name":"Aviation","volume":"25 1","pages":"1-9"},"PeriodicalIF":1.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43729791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-21DOI: 10.3846/aviation.2020.13290
Çağri Bulut, Sefer Aydoğan
In line with the advancing airway capability, the non-aeronautical business opportunities at airports are also in growth. To attract more passengers or to generate extra income over non-aeronautical services, the airport decision-makers need to evaluate the quality of their services. This study aims at introducing an expanded approach to improve airport service quality aspects of the non-aeronautical business opportunities. Given the increasing number of airports, passengers prefer airports, which provide better or extra services compared to others. To reveal the airport service quality (ASQ) aspects, together with the quality department experts, we conducted a qualitative study that put forward six significant dimensions for an effective evaluation of airport service quality at an airport. Based on the results of the qualitative study, we designed the sector-specific questionnaire, and its empirical data is conducted over 250 passengers through a face-toface survey. Survey results introduce a practical assessment tool for the use of airport managers to gather strategic inputs on their strategic plans and quality implications. Results also contribute to the literature by presenting a comprehensive understanding of the airport service quality.
{"title":"AIRPORT SERVICE QUALITY: A RECONCEPTUALIZATION AND A PRACTICAL APPLICATION ON THE NON-AERONAUTICAL SERVICES","authors":"Çağri Bulut, Sefer Aydoğan","doi":"10.3846/aviation.2020.13290","DOIUrl":"https://doi.org/10.3846/aviation.2020.13290","url":null,"abstract":"In line with the advancing airway capability, the non-aeronautical business opportunities at airports are also in growth. To attract more passengers or to generate extra income over non-aeronautical services, the airport decision-makers need to evaluate the quality of their services. This study aims at introducing an expanded approach to improve airport service quality aspects of the non-aeronautical business opportunities. Given the increasing number of airports, passengers prefer airports, which provide better or extra services compared to others. To reveal the airport service quality (ASQ) aspects, together with the quality department experts, we conducted a qualitative study that put forward six significant dimensions for an effective evaluation of airport service quality at an airport. Based on the results of the qualitative study, we designed the sector-specific questionnaire, and its empirical data is conducted over 250 passengers through a face-toface survey. Survey results introduce a practical assessment tool for the use of airport managers to gather strategic inputs on their strategic plans and quality implications. Results also contribute to the literature by presenting a comprehensive understanding of the airport service quality.","PeriodicalId":51910,"journal":{"name":"Aviation","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41957871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-17DOI: 10.3846/aviation.2020.12565
T. Dautermann, T. Ludwig
Instrument approaches to non- instrument runways were made possible by the new approach classification of ICAO. As a conservative solution, the procedure design guidelines by the national civil aviation authorities apply circling minima to those approaches to non-instrument runways. However, the classification as non-instrument runway is very binary. Often a small item causes a reduction from instrument to a non-instrument runway and the circling minima become thus very conservative. Here, two cases are shown, Payerne, a non-instrument runway, and Ouessant with an instrument runway, both equipped very differently but both serving Instrument Flight Rules (IFR) traffic. Solutions for Payerne and other similarly highly equipped non-instrument runways are proposed in order to be able to accommodate at least non-precision minima.
{"title":"DEGENERALIZING INSTRUMENT APPROACH MINIMA TO NON INSTRUMENT RUNWAYS: A CASE STUDY FOR PAYERNE AIRPORT IN SWITZERLAND","authors":"T. Dautermann, T. Ludwig","doi":"10.3846/aviation.2020.12565","DOIUrl":"https://doi.org/10.3846/aviation.2020.12565","url":null,"abstract":"Instrument approaches to non- instrument runways were made possible by the new approach classification of ICAO. As a conservative solution, the procedure design guidelines by the national civil aviation authorities apply circling minima to those approaches to non-instrument runways. However, the classification as non-instrument runway is very binary. Often a small item causes a reduction from instrument to a non-instrument runway and the circling minima become thus very conservative. Here, two cases are shown, Payerne, a non-instrument runway, and Ouessant with an instrument runway, both equipped very differently but both serving Instrument Flight Rules (IFR) traffic. Solutions for Payerne and other similarly highly equipped non-instrument runways are proposed in order to be able to accommodate at least non-precision minima.","PeriodicalId":51910,"journal":{"name":"Aviation","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48605530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-16DOI: 10.3846/aviation.2020.12661
M. Urbaha, K. Stefański, M. Banov, V. Shestakov
The paper presents the results of experimental studies using the acoustic emission method of samples made of fiberglass, the design feature of which is the presence of both base fibers and weft fibers. The test data are presented in relative units and the concept of staged damage accumulation is used, which allows one to recognize subtle phenomena of the nature of the destruction of fiberglass. Tests of the samples with a transverse arrangement of fibers with respect to the applied load showed that the fracture process both in the strain parameters and in the parameters of the total acoustic emission has two stages of damage accumulation: the stage of proportional change of these parameters from stress and the stage of intensive increment of these parameters. In this case, the parameter of the total acoustic emission shows that this process of destruction begins earlier by 5–6% than the strain parameter shows. The proposed methodology and equipment allows us to identify the nature of fracture and assess the tensile strength of such a “staged” composition, and also to solve the problem of what affected the structural unity violations, which may be due to the presence of a set of cracks formed during manufacturing or under the influence of stresses and the external environment during the process of loading.
{"title":"APPLICATION OF ACOUSTIC EMISSION METHOD FOR THE EVALUATION OF THE MICROMECHANICS OF DESTRUCTION OF FIBERGLASS MATERIALS UNDER STATIC LOAD","authors":"M. Urbaha, K. Stefański, M. Banov, V. Shestakov","doi":"10.3846/aviation.2020.12661","DOIUrl":"https://doi.org/10.3846/aviation.2020.12661","url":null,"abstract":"The paper presents the results of experimental studies using the acoustic emission method of samples made of fiberglass, the design feature of which is the presence of both base fibers and weft fibers. The test data are presented in relative units and the concept of staged damage accumulation is used, which allows one to recognize subtle phenomena of the nature of the destruction of fiberglass. Tests of the samples with a transverse arrangement of fibers with respect to the applied load showed that the fracture process both in the strain parameters and in the parameters of the total acoustic emission has two stages of damage accumulation: the stage of proportional change of these parameters from stress and the stage of intensive increment of these parameters. In this case, the parameter of the total acoustic emission shows that this process of destruction begins earlier by 5–6% than the strain parameter shows. The proposed methodology and equipment allows us to identify the nature of fracture and assess the tensile strength of such a “staged” composition, and also to solve the problem of what affected the structural unity violations, which may be due to the presence of a set of cracks formed during manufacturing or under the influence of stresses and the external environment during the process of loading.","PeriodicalId":51910,"journal":{"name":"Aviation","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41376998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-11DOI: 10.3846/aviation.2020.12539
Matías Ginieis, A. Hernández-Lara, M. Sánchez-Rebull
It is important to examine profitability in the aviation sector and the factors that may affect it, due to their relevance for the airlines’ survival. The main purpose of this paper is to analyse the effect of three internal business characteristics,namely labour costs, labour productivity and company size, on airlines’ profitability, considering the airline type as a moderating effect. We have collected data of 190 European airlines during a 10-year period (2004–2013) which allowed us to create an unbalanced panel of 1,364 observations. Four types of airlines are considered. Results show that cost per employee has a positive influence on economic performance, especially for major carriers and regional carriers. It is also confirmed that the carrier type influences the relationship between labour costs, labour productivity and company size on the one hand, and economic returns on the other. These findings are relevant as they improve our understanding of economic profitability in different airlines’ types.
{"title":"INFLUENCE OF AIRLINES’ SIZE AND LABOUR COSTS ON PROFITABILITY","authors":"Matías Ginieis, A. Hernández-Lara, M. Sánchez-Rebull","doi":"10.3846/aviation.2020.12539","DOIUrl":"https://doi.org/10.3846/aviation.2020.12539","url":null,"abstract":"It is important to examine profitability in the aviation sector and the factors that may affect it, due to their relevance for the airlines’ survival. The main purpose of this paper is to analyse the effect of three internal business characteristics,namely labour costs, labour productivity and company size, on airlines’ profitability, considering the airline type as a moderating effect. We have collected data of 190 European airlines during a 10-year period (2004–2013) which allowed us to create an unbalanced panel of 1,364 observations. Four types of airlines are considered. Results show that cost per employee has a positive influence on economic performance, especially for major carriers and regional carriers. It is also confirmed that the carrier type influences the relationship between labour costs, labour productivity and company size on the one hand, and economic returns on the other. These findings are relevant as they improve our understanding of economic profitability in different airlines’ types.","PeriodicalId":51910,"journal":{"name":"Aviation","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47916542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-09DOI: 10.3846/aviation.2020.12714
Yu. M. Ignatkin, P. Makeev, S. Konstantinov, A. Shomov
The presented work is dedicated to the numerical study of the aerodynamic characteristics of the helicopter rotor. Two approaches to modeling of the rotor are applied: the free wake model developed by the Authors with using steady airfoil characteristics and the Unsteady RANS method based on the Ansys Fluent software. The modes of hovering and horizontal flight in the range of advancing ratio μ = (0-0.45) are considered. The shapes of the rotor wake, the distributions of the normal force coefficient and the fields of inductive velocities for all considered flight modes are calculated. For a particular case with μ = 0.25 there is a comparison with experimental data. The time needed for calculation of the applied methods is estimated. Accuracy of the used methods in the framework of the solved task is analysed with taking into account used models assumptions. It is shown that in the range of μ = (0-0.25) the free wake model provides a fast and reliable calculation of the aerodynamic characteristics of the helicopter rotor. For values of μ > 0.35 it is necessary to take into account the unsteady characteristics of the airfoil.
{"title":"MODELLING THE HELICOPTER ROTOR AERODYNAMICS AT FORWARD FLIGHT WITH FREE WAKE MODEL AND URANS METHOD","authors":"Yu. M. Ignatkin, P. Makeev, S. Konstantinov, A. Shomov","doi":"10.3846/aviation.2020.12714","DOIUrl":"https://doi.org/10.3846/aviation.2020.12714","url":null,"abstract":"The presented work is dedicated to the numerical study of the aerodynamic characteristics of the helicopter rotor. Two approaches to modeling of the rotor are applied: the free wake model developed by the Authors with using steady airfoil characteristics and the Unsteady RANS method based on the Ansys Fluent software. The modes of hovering and horizontal flight in the range of advancing ratio μ = (0-0.45) are considered. The shapes of the rotor wake, the distributions of the normal force coefficient and the fields of inductive velocities for all considered flight modes are calculated. For a particular case with μ = 0.25 there is a comparison with experimental data. The time needed for calculation of the applied methods is estimated. Accuracy of the used methods in the framework of the solved task is analysed with taking into account used models assumptions. It is shown that in the range of μ = (0-0.25) the free wake model provides a fast and reliable calculation of the aerodynamic characteristics of the helicopter rotor. For values of μ > 0.35 it is necessary to take into account the unsteady characteristics of the airfoil.","PeriodicalId":51910,"journal":{"name":"Aviation","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46640963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-05DOI: 10.3846/aviation.2020.12507
M. Honari-Torshizi, H. Rahmani, H. Moeinkhah, M. Gharib, J. Jahanpour
Control of a Twin Rotor Multi-input Multi-output System (TRMS) is not a simple work. Because it has complex nonlinear dynamics, cross-coupling, uncertainties, and instability. This paper provides a practical method for control of a TRMS, named Quantitative Feedback Theory (QFT) as one of the robust approaches. Firstly, the TRMS set and modeling procedure are introduced. Secondly, the nonlinear and linear equations of electrical and mechanical parts in both vertical and horizontal planes are presented. Next, using the QFT method, a controller is designed for motion in each plane. Finally, the robustness of the control strategy is illustrated by simulations of vertical and horizontal motions, including controller and pre-filter in the presence of uncertainties. The results demonstrate that the proposed robust controller can guarantee the system stabilization, as well as pitch and yaw tracking of TRMS.
{"title":"A QFT ROBUST CONTROLLER AS A REMEDY FOR TRMS","authors":"M. Honari-Torshizi, H. Rahmani, H. Moeinkhah, M. Gharib, J. Jahanpour","doi":"10.3846/aviation.2020.12507","DOIUrl":"https://doi.org/10.3846/aviation.2020.12507","url":null,"abstract":"Control of a Twin Rotor Multi-input Multi-output System (TRMS) is not a simple work. Because it has complex nonlinear dynamics, cross-coupling, uncertainties, and instability. This paper provides a practical method for control of a TRMS, named Quantitative Feedback Theory (QFT) as one of the robust approaches. Firstly, the TRMS set and modeling procedure are introduced. Secondly, the nonlinear and linear equations of electrical and mechanical parts in both vertical and horizontal planes are presented. Next, using the QFT method, a controller is designed for motion in each plane. Finally, the robustness of the control strategy is illustrated by simulations of vertical and horizontal motions, including controller and pre-filter in the presence of uncertainties. The results demonstrate that the proposed robust controller can guarantee the system stabilization, as well as pitch and yaw tracking of TRMS.","PeriodicalId":51910,"journal":{"name":"Aviation","volume":"24 1","pages":"137-148"},"PeriodicalIF":1.0,"publicationDate":"2020-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49351558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-11DOI: 10.3846/aviation.2020.11978
R. Chatys
The paper deals with aspects of the complexity of mechanical properties of porous structures made from copper fibers and fibers reinforced with copper meshes to assess the adhesive strength of the fibrous structure and the cohesion between the components of the tested elements used for the construction of heat exchangers. All of the tested samples were characterized by macroscopic open porosity. The internal structure of the obtained connections was analyzed by metallographic techniques. Statistical relations of the connections made between the layers have been provided. The side effects of the production technology related to the “hydrogen disease” of copper have been discussed.
{"title":"ASPECTS OF COMPLEXITY OF METAL-FIBROUS MICROSTRUCTURE FOR THE CONSTRUCTION OF HIGH-PERFORMANCE HEAT EXCHANGERS: ESTIMATION OF ADHESIVE STRENGTH","authors":"R. Chatys","doi":"10.3846/aviation.2020.11978","DOIUrl":"https://doi.org/10.3846/aviation.2020.11978","url":null,"abstract":"The paper deals with aspects of the complexity of mechanical properties of porous structures made from copper fibers and fibers reinforced with copper meshes to assess the adhesive strength of the fibrous structure and the cohesion between the components of the tested elements used for the construction of heat exchangers. All of the tested samples were characterized by macroscopic open porosity. The internal structure of the obtained connections was analyzed by metallographic techniques. Statistical relations of the connections made between the layers have been provided. The side effects of the production technology related to the “hydrogen disease” of copper have been discussed.","PeriodicalId":51910,"journal":{"name":"Aviation","volume":"24 1","pages":"117-122"},"PeriodicalIF":1.0,"publicationDate":"2020-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41518113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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