• 한국군사과학기술학회지
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• 제26권2호
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• pp.129-138
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• 2023

Acquiring precise coordinates of ground targets can be regarded as the key mission of the tactical-level military UAS(Unmanned Aerial System) operations. The coordinates deviations for the ground targets estimated from UAV (Unmanned Aerial Vehicle) images may depend on the sensor specifications and slant ranges between UAV and ground targets. It has an order of several tens to hundreds of meters for typical tactical UAV mission scenarios. In this paper, we propose a scheme that precisely acquires target coordinates from UAS by mapping image pixels to geographical coordinates based on GCP(Ground Control Points). This scheme was implemented and tested from ground control station for UAS. We took images of targets of which exact location is known and acquired the target coordinates using our proposed scheme. The experimental results showed that errors of the acquired coordinates remained within an order of several meters and the coordinates accuracy was significantly improved.

• Journal of Advanced Marine Engineering and Technology
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• 제37권7호
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• pp.737-742
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• 2013

Recently, unmanned aircrafts for safe measurement in hazardous locations have been developed. In a method of operation of unmanned aircraft vehicles (UAV), there are two methods of manual control and automatic control. Small UAVs are used for low altitude surveillance flights where unknown obstacles can be encountered. Obstacle avoidance is one of the most challenging tasks which the UAV has to perform with high level of accuracy. In this study, we used a laser range finder as an obstacle detector in automatic navigation of unmanned aircraft to patrol the destination automatically. We proposed a system to avoid obstacles automatically by measuring the angle and distance of the obstacle using the laser range finder.

• 항공우주시스템공학회지
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• 제7권3호
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• pp.65-69
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• 2013

Avionics system designed for the 200 kg-class tiltrotor UAV has been developed. Avionics system for the UAV is the reconstruct system and can be programmed automation controller. This paper focuses on the design aspects of the hardware and presents the ground and flight test results. The hardware aspects of the avionics system include details about the hardware configurations for the interfaces with the Digital Flight Control Computer, sensors and Line-replaceable unit modifications.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.533-536
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• 2009

스마트무인기의 추진동력계통은 터보프롭 항공기와 유사한 피치 가버닝 개념으로 조종사가 엔진동력을 직접 입력하고 제어기는 프롭로터의 회전속도를 일정하게 유지하는 방식을 사용한다. 본 논문에서는 스마트무인기의 지상시험 결과 중 엔진관련 데이터를 추출하여 전기 작동기로 구동되는 엔진 Power Lever 각도의 변위값과 가스발생기 회전속도의 상관관계 및 동력 변화를 엔진성능계산프로그램으로 예측한 결과과 비교한다.

• 제어로봇시스템학회논문지
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• 제11권3호
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• pp.200-206
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• 2005

In this paper, a redundancy management system for aircraft is studied, and FDI (Fault Detection and Isolation) algorithm of inertial sensor system is proposed. UAV system cannot allow triple or quadruple hardware redundancy due to the limitations on space and weight. In the UAV system with dual sensors, it is very difficult to identify the faulty sensor. Also, conventional FDI method cannot isolate multiple faults in a triple redundancy system. In this paper, hardware based FDI technique is proposed, which combines a parity equation approach with the wavelet based technique, which is a model-free FDI method. To verify the effectiveness of the proposed FDI method, numerical simulations are performed.

• 항공우주기술
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• 제6권2호
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• pp.236-244
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• 2007

스마트무인기의 기본 비행성능 파악과 비행제어 알고리즘의 검증을 위하여 40% 축소형 비행체를 개발하였다. 축소형 비행체는 실물기와 유사한 형태의 짐발 허브와 드라이브 장치를 채택하였으며 강제 공랭 방식의 왕복엔진을 장착하였다. 축소형 비행체 주요 부품에 대한 다양한 시험을 수행하였고 조립된 축소형 비행체의 지상시험 및 호버링 시험을 통하여 주요 성능과 기계적 내구성을 확인하였다.

• 제어로봇시스템학회논문지
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• 제22권1호
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• pp.17-23
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• 2016

This paper presents the implementation of altitude and attitude measurement algorithm using stereo camera for an unmanned aerial vehicle (UAV). Depth images are generated by calibrating the stereo cameras, and converted into 3D point cloud data. By applying a plane fitting algorithm to the resultant point cloud, altitude from ground level, and roll and pitch angles are extracted. To verify the performance, experimental results are provided by comparing with those of the motion caption system.

• Journal of information and communication convergence engineering
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• 제4권1호
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• pp.28-35
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• 2006

In this paper, we propose to synchronization method for mutual cooperative control method that have unstable limit cycles in a chaos trajectory surface in the chaotic UAVs. We assume all obstacles in the chaos trajectory surface have a Van der Pol equation with an unstable limit cycle. We also show computer simulation results of Arnold equation, Chua's equation trajectories with one or more Van der Pol as a obstacles. We proposed and verified the results of the method to make the embedding chaotic UAV to synchronization with the chaotic trajectory in any plane.

• Advances in aircraft and spacecraft science
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• 제6권5호
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• pp.371-389
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• 2019

The implementation of a robust $H_{\infty}$ Control, which is numerically efficient for uncertain nonlinear dynamics, on longitudinal and lateral autopilots is realised for a quarter scale Piper J3-Cub model accepted as an unmanned aerial vehicle (UAV) under the condition of sensor noise and disturbance effects. The stability and control coefficients of the UAV are evaluated through XFLR5 software, which utilises a vortex lattice method at a predefined flight condition. After that, the longitudinal trim point is computed, and the linearization process is performed at this trim point. The "${\mu}$-Synthesis"-based robust $H_{\infty}$ control algorithm for roll, pitch and yaw displacement autopilots are developed for both longitudinal and lateral linearised nonlinear dynamics. Controller performances, closed-loop frequency responses, nominal and perturbed system responses are obtained under the conditions of disturbance and sensor noise. The simulation results indicate that the proposed control scheme achieves robust performance and guarantees stability under exogenous disturbance and measurement noise effects and model uncertainty.

• 제어로봇시스템학회논문지
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• 제14권12호
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• pp.1260-1265
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• 2008

This study deals with modeling and flight control of quadrotor type (QRT) unmanned aerial vehicles (UAVs). Rigorous dynamic model of a QRT UAV is obtained both in reference and body frame coordinate systems. A disturbance observer (DOB) based controller using the derived dynamic models is also proposed for robust hovering control. The control input induced by DOB is helpful to use simple equations of motion satisfying accurate derived dynamics. The experimental results show the performance of the proposed control algorithm.