• Journal of IKEEE
• /
• v.25 no.3
• /
• pp.540-543
• /
• 2021

In this paper, we present an experimental comparative study of recurrent neural network based techniques for trajectory prediction of flight vehicles. We defined and investigated various relationships between input and output under the same experimental setup. In particular, we proposed a relationship based on the relative positions of flight vehicles. Furthermore, we conducted an ablation study on the network architectures and hyperparameters. We believe that this comprehensive comparative study serves as a reference point and guide for developers in choosing an appropriate recurrent neural network based techniques for building (flight) vehicle trajectory prediction systems.

• International Journal of Aeronautical and Space Sciences
• /
• v.9 no.2
• /
• pp.71-78
• /
• 2008

New formation flight controller for unmanned aerial vehicles is proposed. A behavioral decentralized control approach called formation geometry center control is adopted. Trajectory tracking as well as formation geometry keeping are the purpose of the formation flight, and therefore two controllers are designed: a trajectory tracking controller for reference trajectory tracking, and a position controller for formation geometry keeping. Each controller is designed using Lyapunov stability theorem to guarantee the asymptotic stability. Formation flight controller is finally obtained by combining the trajectory tracking controller and the formation geometry keeping controller using a weighting parameter that depends on the relative distance error between unmanned aerial vehicles. Numerical simulations are performed to validate the performance of the proposed controller.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.47 no.4
• /
• pp.266-273
• /
• 2019

The efficiency and effectiveness of mission performance can be greatly changed according to the operating conditions such as the number of manned aircraft, flight altitude, and so on, in performing search and reconnaissance missions using a large number of small reconnaissance unmanned aerial vehicles. However, it is not easy to determine which operating conditions are most reasonable. Therefore, in this study, we developed an unmanned airplane flight simulation that can detect and identify the target while avoiding collision according to autonomous flight, suggesting a way to derive operating conditions when operating a large number of unmanned aerial vehicles.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.49 no.12
• /
• pp.981-988
• /
• 2021

This paper presents a decentralized guidance algorithm for swarm flight of fixed-wing UAVs (Unmanned Aerial Vehicles). Considering swarm flight missions, we assume four representative swarm tasks: gathering, loitering, waypoint/path following, and individual task. Those tasks require several distinct maneuvers such as path following, flocking, and collision avoidance. In order to deal with the required maneuvers, this paper proposes an integrated guidance algorithm based on vector field, augmented Cucker-Smale model, and potential field methods. Integrated guidance command is synthesized with heuristic weights designed for each guidance method. The proposed algorithm is verified through flight tests using up to 19 small fixed-wing UAVs.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.26 no.3
• /
• pp.252-261
• /
• 2023

Analysis of dynamic characteristics and flight vibration test for unmanned aerial vehicles was studied by using dummy test body. The FEM model for dummy test body was supplemented by results of modal and random vibration test. The free end boundary condition to simulate flight environments was made by test setup using bungee cable. Prior to the flight vibration test using a dual electric vibration exciters, the test procedure to calculate quantitative vibration level was studied by using military specification. The actual test was successfully done by using the analysis and pretest results. From the analysis results, it was possible to determine the feasibility of the test by predicting the excitation force of the flight vibration test and to get the response of any point which could not be measured by the test. The results of this study will much contribute to the Test and Evaluation of unmanned aerial vehicles.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.43 no.3
• /
• pp.243-256
• /
• 2015

As a part of the R&D efforts for the hypersonic vehicles, various flight test programs has been carried out using small launch vehicles or sounding rockets. Australian HyShot program is a representative case of the flight test program for scramjet engines carried by international collaborations. A number of hypersonic flight test programs has followed in a similar way. In USA, Falcon HTV-2 was carried by DARPA, X-51A by AFRL and HyFly by ONR. HyCAUSE and HIFiRE were carried in collaboration with Australia. In France, LEA program is on the way similarly to X-51A. Russia, China and India seems like carrying out flight test programs for the development of hypersonic defense system. The goals, technical elements, the status and the relation between the programs were summarized in this paper as a reference for the similar program of the country in the future.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.25 no.4
• /
• pp.170-176
• /
• 2017

In recent years, Unmanned Aerial Vehicles (UAVs) were actively developed in various fields. In development process of UAVs, flight test is performed to ensure that minimum safety requirements and technical requirements are met. By constructing flight test infrastructure such as takeoff and landing facilities, operation procedure, and equipments, flight test can be performed effectively. In this paper, operation procedures of civil UAV's flight test are proposed. The procedures proposed are composed by two main steps: first, planning and permitting procedure of flight test. Secondly, execution and control procedure of flight test.

• Journal of IKEEE
• /
• v.22 no.3
• /
• pp.747-753
• /
• 2018

Currently, many companies have succeeded in logistics delivery experiments utilizing drone and report it. When a drone is used commercially, long-term flight is an important performance that a drone should have. However, unlike vehicles operated on the ground, drone is a vehicle that continues to consume energy when maintaining the current altitude or moving to the destination. Therefore, the drones can fly for a long time as the capacity of the battery is large, but the batteries with large capacity are restricted by heavy weight and it acts as a limiting factor in a commercial use. To address this issue, we attempt to compare how far we can fly than forward flight based on the flight pattern with the same energy consumption condition. In this paper, the comparison of energy consumption was performed in three flight pattern, forward flight without altitude change and forward flight with altitude change, by computer simulation and it shows the increasing of flight distances when the quadrotor fly with altitude change from high altitude to low altitude.

• Journal of Aerospace System Engineering
• /
• v.2 no.1
• /
• pp.17-21
• /
• 2008

A compact, light-weight, integrated flight control computer(IFCC) for small unmanned autonomous vehicles is developed. Its design objective is to produce an all in one avionics system which includes the navigation sensor, data link, attitude sensors and air data sensors. The initial phase of ground and flight tests are performed to verify the prototype IFCC, showing promising results. The high potential of its application is expected.

• Journal of IKEEE
• /
• v.25 no.4
• /
• pp.766-769
• /
• 2021

In order to perform tasks such as design, control, optimization, and prediction of flight vehicle trajectories based on machine learning techniques including deep learning, a certain amount of flight vehicle trajectory data is required. However, there are cases in which it is difficult to secure more than a certain amount of flight vehicle trajectory data for various reasons. In such cases, synthetic data generation could be one way to make machine learning possible. In this paper, to explore this possibility, we generated and evaluated synthetic flight vehicle trajectory data using time-series generative adversarial neural network. In addition, various ablation studies (comparative experiments) were performed to explore the possibility of using synthetic data in the aircraft trajectory prediction task. The experimental results presented in this paper are expected to be of practical help to researchers who want to conduct research on the possibility of using synthetic data in the generation of synthetic flight vehicle trajectory data and the work related to flight vehicle trajectories.