• IEMEK Journal of Embedded Systems and Applications
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• v.15 no.3
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• pp.149-157
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• 2020

Regarding previously-developed drone simulators, it was easy to check their flight stability or controlling functions based on the condition that their weight was fixed from the design. However, the drone is largely classified into two types that is the one with the fixed weight whose purpose is recording video with camera and racing and another is whole weight-variable during flight with loading the articles for delivery and spraying pesticide though the weight of airframe is fixed. The purpose of this thesis is to analyze the structure of drone and its flight principle, suggest dynamics-model-based simulator that is capable of simulating weight-variable drone and develop the simulator that can be used for designing main control board, motor and transmission along the application of weight-variable drone. Weight-variable simulator was developed by using various calculation to apply flying method of drone to the simulator. First, ground coordinate system and airframe-fixing coordinate system were established and switching matrix of those two coordinates were made. Then, dynamics model of drone was established using the law of Newton and moment balance principle. Dynamics model was established in Simulink platform and simulation experiment was carried out by changing the weight of drone. In order to evaluate the validity of developed weight-variable simulator, it was compared to the results of clean flight public simulator against existing weight-fixed drone. Lastly, simulation test was performed with the developed weight-variable simulation by changing the weight of drone. It was found out that dynamics model controlled various flying positions of drone well from simulation and the possibility of securing the optimum condition of weight-variable drone that has flying stability and easiness of controlling.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.5
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• pp.416-422
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• 2016

This paper presents preliminary performance analysis of a satellite formation flying testbed, which is under development by Astrodynamics and Control Laboratory, Department of Astronomy, Yonsei University. A model reference adaptive controller (MRAC) with a first-order reference model is chosen to enhance the response of reaction wheel system which is subject to uncertainties caused by unmodelled dynamics and measurement noise. In addition, an on-line parameter estimation (OPE) technique based on the least square is combined to eliminate the effect of angular measurement noise by estimating the moment of inertia. Both numerical simulations and hardware experiments with MRAC support the effectiveness and applicability of the adaptive control scheme, which maintains the tracking error below $0.25^{\circ}$ for the entire time span. However, the high frequency control input generated in hardware experiment strongly suggests design modifications to reduce the effect of deadzone.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.688-693
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• 2016

This paper describes the parachute dynamics modeling and simulation results for the development of training simulator of a HALO (High Altitude Low Opening) parachute, which is currently in use for military purposes. The target parachute is a rectangular shaped parafoil and its dynamic model is derived based on the real geometry data as the 9-DOF nonlinear equations of dynamics. The simulation was conducted through the moment of inertia and its aerodynamic derivatives to reflect the real characteristics based on the MATLAB/Simulink. In particular, its modeling includes the typical characteristics of the added mass and moment of inertia, which is shown in the strong effects in Lighter-Than-Air(LTA) flight vehicle. The proposed dynamic modeling was evaluated through the simulation under the spiral turning flight conditions of the asymmetric control inputs and compared with the performance index in the target parachute manual.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.95-101
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• 2024

This paper aims to establish a reconfigurable flight simulation environment to conduct safety evaluation of various electric vertical take-off and landing (eVTOL) aircraft. Since the inceptor, aircraft dynamics model, and controller applied to each eVTOL aircraft are different, it was configured to be variable so that a simulation can be executed for each eVTOL aircraft. Test elements and performance indicators were set to perform safety evaluation of eVTOL aircraft. Ground auxiliary equipments were designed and implemented in a simulation environment according to test procedures for each test element. In addition, to analyze safety performance, a simulation flight data collection environment based on MATLAB/Simulink and a tool for safety performance analysis were implemented. Test flight and analysis were conducted in the implemented simulation environment in this paper. Finally, this study shows the environment was verified by confirming that it was performed normally.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.8
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• pp.731-738
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• 2015

The rapid prototyping process and development tool which enable the control law evaluation efficiently are needed to minimize the development cycle, cost and risk of aircraft flight control system. This paper describes a development process that integrates the designed control law into HETLAS to evaluate simulation effectively using nonlinear mathematical models. The desktop engineering simulator was developed using HETLAS for the piloted simulation evaluation of a various control modes and the procedure was developed, which quickly integrates the HETLAS into HQS(Handling Quality Simulator) and HILS(Hardware In the Loop Simulation) environments. This paper presents a rapid prototyping process using HETLAS that significantly shortens the integration process of the control law into the nonlinear math model, HETLAS, and allows the control law designs to be quickly tested in the piloted simulation and HILS environments.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.4
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• pp.50-58
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• 2017

Recently, some methods of converging heterogeneous fire sensor data have been proposed for effective fire detection, but the rule-based methods have low adaptability and accuracy, and the fuzzy inference methods suffer from detection speed and accuracy by lack of consideration for images. In addition, a few image-based deep learning methods were researched, but it was too difficult to rapidly recognize the fire event in absence of cameras or out of scope of a camera in practical situations. In this paper, we propose a novel fire detection system combining a deep learning algorithm based on CNN and fuzzy inference engine based on heterogeneous fire sensor data including temperature, humidity, gas, and smoke density. we show it is possible for the proposed system to rapidly detect fire by utilizing images and to decide fire in a reliable way by utilizing multi-sensor data. Also, we apply distributed computing architecture to fire detection algorithm in order to avoid concentration of computing power on a server and to enhance scalability as a result. Finally, we prove the performance of the system through two experiments by means of NIST's fire dynamics simulator in both cases of an explosively spreading fire and a gradually growing fire.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.910-917
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• 2018

This paper describes the developments to improve the feeling and safety of the remote control system of unmanned vehicles. Generally, in the case of the remote control systems, a joystick-type device or a simple steering-wheel are used. There are many cases, in which there are operations without considering the feedback to users and driving feel. Recently, as the application area of the unmanned vehicles has been extended, the problems caused by not considering the feedback are emphasized. Therefore, the need for a force feedback-haptic control arises to solve these problems. In this study, the force feedback-haptic control algorithm considering the vehicle parameters is proposed. The vehicle parameters include first the state variables of dynamics, such as the body side-slip angle (${\beta}$) and yawrate (${\gamma}$), and second, the parameters representing the driving situations. Force feedback-haptic control technology consists of the algorithms for general and specific situations, and considers the situation transition process. To verify the algorithms, a simulator was constructed using the vehicle dynamics simulation tool with CAN communication environment. Using the simulator, the feasibility of the algorithms was verified in various scenarios.