• Journal of Advanced Navigation Technology
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• v.16 no.2
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• pp.197-203
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• 2012

In this paper, study the substantial issues which occurs upon free flight environment by performing separation assurance under multiple conflict(over 3 Aircraft), recovery en route under the terms of time constrains and fixed way point after the conflict avoidance, correlations between conflict detection distance and separation assurance by utilizing Autonomous flight algorithm. Result of this experiment demonstrates that the extension of detection distance is advantageous to solution of separation assurance and enhancing of flight efficiency, choose to maneuver by applying time constrain terms and fixed way point according to the situation of conflict prediction in case of recovery maneuver after the conflict avoidance. And separation assurance can be solved by applying 2 degrees or more of bank angle. When choosing the optimal bank angle could be drastically improved flight efficiency.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.10
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• pp.927-932
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• 2007

The sophisticated mathematical model is required for the design and the database construction of the advanced flight control system of UAV. In this paper, flight test of KARI's research UAV, often called DURUMI-II, is implemented for the data acquisition from the maneuver flight. The flight path reconstruction is implemented to ensure that the measured data is consistent and error free. The nonlinear system identification for the refined mathematical modeling is implemented with the verified measurements from the flight path reconstruction. The simulation with the identified results have a good validation when the simulated responses were compared to the flight tested data.

• ETRI Journal
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• v.43 no.4
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• pp.580-593
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• 2021

When operating in confined spaces or near obstacles, collision-free path planning is an essential requirement for autonomous exploration in unknown environments. This study presents an autonomous exploration technique using a carefully designed collision-free local planner. Using LiDAR range measurements, a local end-point selection method is designed, and the path is generated from the current position to the selected end-point. The generated path showed the consistent collision-free path in real-time by adopting the Euclidean signed distance field-based grid-search method. The results consistently demonstrated the safety and reliability of the proposed path-planning method. Real-world experiments are conducted in three different mines, demonstrating successful autonomous exploration flights in environment with various structural conditions. The results showed the high capability of the proposed flight autonomy framework for lightweight aerial robot systems. In addition, our drone performed an autonomous mission in the tunnel circuit competition (Phase 1) of the DARPA Subterranean Challenge.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.379-388
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• 2015

In the end of 1990's, future free flight technology had been developed and tested in America and government established the plan for free flight until 2017. Aircraft separation assurance must be secured essentially to avoid collision between aircrafts before Free Flight comes true. Now, Civil aircraft has rules about avoidance activity with traffic collision avoidance system (TCAS) but it can't apply to light aircraft. So there is a need about alternative method to apply light-aircraft because it has space and price problem to use TCAS. In this paper, TCAS algorithm has been modified and verified by simulating with LABVIEW program under ADS-B condition to get miniaturization and weight lighting cheaply. By simulating, collision alert algorithm is analyzed and verified with collision situation proposed by ICAO, and 100% checked for performing the alert announciation on all cases by TCAS standards.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.4
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• pp.142-147
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• 2007

When the aircraft is developed, several flight tests are performed including stability and controllability, performance and systems, above all the most important part of the flight test is stability test. Stability test is divided into two parts, static stability and dynamic stability. Static stability of the aircraft is typically defined in terms of its initial tendency to return to equilibrium after a disturbance and not included time concept. One of static stability, longitudinal static stability, was addressed here. The longitudinal static stability was studied from the basic theory to the flight test method and also explained data reduction method throughout the flight test. Finally showed how to meet the specifications such as ROC, FAR and MIL-specifications.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.2
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• pp.63-70
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• 2012

The collision-free flight planning method based on the extended collision map is proposed for cooperation of multiple unmanned aerial vehicles (UAVs) in a common 3-dimensional workspace. First, a UAV is modeled as a sphere, taking its 3-D motions such as rolling into consideration. We assume that after entering the common workspace, the UAVs move along their straight paths until they depart from the workspace, and that the priorities of the UAVs are determined in advance. According to the assumptions, the collision detection problem between two spheres in $R^3$ can be reduced into the collision detection problem between a circle and a line in $R^2$. For convenience' sake and safety, the collision regions are approximated by collision boxes. Using the collision boxes, the entrance times of the UAVs are scheduled for collision avoidance among the UAVs. By this way, all UAVs can move in the common workspace without collisions with one another. For verifying the effectiveness of the proposed flight planning method, the simulation with 12 UAVs is carried out.

• Proceedings of the KWS Conference
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• 2002.05a
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• pp.121-122
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• 2002

• Advances in aircraft and spacecraft science
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• v.8 no.4
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• pp.273-287
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• 2021

Model-based, data-driven and physics-based approaches represent the state-of-the-art techniques to estimate the aircraft flow angles, angle-of-attack and angle-of-sideslip, in avionics. Thanks to sensor fusion techniques, a synthetic sensor is able to provide estimation of flow angles without any dedicated physical sensors. The work deals with a physics-based scheme derived from flight mechanic theory that leads to a nonlinear flow angle model. Even though several solvers can be adopted, nonlinear models can be replaced with less accurate but straightforward ones in practical applications. The present work proposes a linearisation to obtain the flow angles' closed form solution that is verified using a flight simulator. The main objective of the paper, in fact, is to analyse the estimation degradation using the proposed closed form solutions with respect to the nonlinear scheme. Moreover, flight conditions, where the proposed closed form solutions are not applicable, are identified.

• Journal of Korean Society for Quality Management
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• v.46 no.1
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• pp.135-152
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• 2018

Purpose: This study attempted to analyze how the ego state of flight attendants affects their job satisfaction and customer orientation using Berne's (1966) transactional analysis and further compare the difference between job satisfaction and customer orientation depending on demographic characteristics, position, and ego state. Methods: The data was collected by using the structured questionnaires to flight attendant of major airline companies. The proposed research model is tested using 164 valid questionnaires using SPSS 23 and Smart PLS 2. Results: This research indicated the only free child ego sate among ego state factors of flight attendant was found to have a positive impact on job satisfaction. In the relationship between ego states and customer orientation, all ego state factors were found to have a significant influence on customer orientation. Conclusions: The study offered a theoretical and empirical foundation for future research by empirically identifying the relationship between ego state factors and customer orientation in the in-flight service and suggested the strategic implications to increase job satisfaction and customer orientation based on the psychology and ego state of flight attendant.

• Journal of Aerospace System Engineering
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• v.9 no.1
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• pp.12-18
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• 2015

The inter-conversion between different control laws in flight has a lot of risk. The SWM(Switching Mechanism) including logic and stand-by mode is designed to analyze the transient response of aircraft during inter-conversion between different control laws, based on the in-house software for non-real-time and real-time simulation. The SWM applies the fader logic of TFS(Transient Free Switch) to minimize the transient response of an aircraft during the inter-conversion, and applies the reset '0' type of the stand-by mode to prevent surface saturation due to integrator effect in the disengaged flight control law. The transition time is also important to minimize the objectionable transient response in the inter-conversion, as well as the transition control law design. This paper addresses the results of non-real-time simulation for the characteristics of transient response to different transition time to select the adequate transient time, and the real-time pilot evaluation, using SSWM(Software Switching Mechanism) and HSWM(Hardware Switching Mechanism), which is met for Level 1 flying qualities and assures safety of flight.