• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
• /
• pp.238-242
• /
• 1994

Shuster's algorithm for spin-axis determination is extended to include sensor bias and mounting angle as its solve-for parameters. The relation between direct and derived measurements bias is obtained by linearizing their kinematic equations. A one-step least-square estimation technique referred to as the 'closed form' solution is used, and the solution provides a more refined and decent initial guess for the subsequent filtering process contained within the differential correction module. The modified algorithm is applied for attitude determination of a GEO communication satellite in transfer orbit, and its results are presented.

• Journal of Advanced Marine Engineering and Technology
• /
• 제38권10호
• /
• pp.1318-1326
• /
• 2014

The purpose of a tracking control system is to track a moving target and to find the exact information of the target. If the platform of the tracking control system is equipped on a moving vehicle such as a ship, the tracking control system will treat even the additional platform motion. In order to avoid the complexity comprising the tracking control system, a process to treat the platform motion, named stabilizing system, must be separated from the tracking control system. In this paper, a method to comprise an attitude control system for the platform stabilization is proposed using an adaptive fuzzy control which is applicable to the system with structural and parametric uncertainty. The suggested adaptive fuzzy control algorithm is the 2nd/1st-type indirect adaptive fuzzy control algorithm using the advantages of 1st-type and 2nd-type indirect adaptive fuzzy control algorithm. Several experiments using the implemented stabilizing system are executed for verifying the effectiveness of the suggested method.

• 제어로봇시스템학회논문지
• /
• 제11권3호
• /
• pp.233-239
• /
• 2005

This paper presents the design and evaluation of a tiltrotor attitude controller. The implemented response type of the command augumentation system is Attitude Command Attitude Hold. The controller architecture can alleviate the need for extensive gain scheduling and thus has the potential to reduce development time. The control algorithm is constructed using the feedback linearization technique. And an on-line adaptive architecture that employs a neural network compensating the model inversion error caused by the deficiency of full knowledge tiltrotor aircraft dynamics is applied to augment the attitude control system. The use of Lyapunov stability analysis guarantees boundedness of the tracking error and network parameters. The performance of the controller is evaluated against ADS-33E criteria, using the nonlinear tiltrotor simulation code for Bell TR301 developed by KARI. (Korea Aerospace Research Institute)

• 한국지능시스템학회논문지
• /
• 제13권1호
• /
• pp.91-96
• /
• 2003

본 논문에서는 비행물체의 운동에 기초한 지능제어 알고리즘을 사용하여 대기의 환경적 요인과 기체형태 및 추력의 인위적 요인들간의 복잡한 함수관계를 지식과 경험에 의한 제어규칙으로서 비행안정성 확보와 자율비행을 위한 비행 자세제어를 행하였다. 비행 자세제어를 위하여 사용한 지능제어기는 다변수 입력 및 출력이 가능하며 강인성을 지닌 퍼지제어기를 사용하였다. 실험을 위해 모형비행기와 자세 검출용 센서를 제작하고, 비행 전문가의 지식과 경험을 기초로 하여 작성한 제어규칙에 의하여 프로그램 된 퍼지제어기를 수 차례의 시험비행을 통해 제어규칙을 조정한 결과 안정된 자세제어를 행할 수 있었다

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2003년도 ICCAS
• /
• pp.876-881
• /
• 2003

Reliable attitude estimation during the launch and early orbit phase is a critical issue for a satellite. Typically gyroscopes and other sensors are utilized to estimate the attitude during this phase. It is difficult to estimate the attitude quickly and reliably using gyroscopes because it requires a large computational load and accurate sensor measurements. Furthermore, the gyroscope failure may lead to the loss of the satellite. This paper suggests a simple attitude estimation method of a low earth orbit satellite without using gyroscopes, but only using sun sensors and magnetometers in the sun-acquisition mode. Using Kompsat-I telemetry data, we verified that the suggested algorithm provides attitude estimation within 3 degrees on each axis.

• 전기학회논문지
• /
• 제63권9호
• /
• pp.1259-1265
• /
• 2014

In this paper, the real-time attitude determination based Matlab using low-cost receivers was designed and evaluated. The GNSS attitude determination system was implemented to operation in real-time by TimerCallback in MATLAB. The TTM(Transmission Time Misalignment) of U-blox receiver was confirmed through zero baseline tests and this problem was revised. The computed attitude by the high-cost NovAtel receiver was compared to the computed attitude by the low-cost U-blox receiver. As a result of this, the performance of attitude determination systems by low-cost receiver was confirmed. To determine baseline, LAMBDA and BC-LAMBDA for integer ambiguities search methods were used. To confirm suitable integer ambiguity search method in real-time attitude determination algorithm, determined baselines by two methods were compared, and it was confirmed that BC-LAMBDA is more suitable. As a result of this, the operation of real-time attitude determination system was confirmed using 3 low-cost receivers.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2004년도 ICCAS
• /
• pp.57-62
• /
• 2004

This paper deals with a waypoint trajectory following problem for the tilt-rotor UAV under development in Korea (TR-KUAV). In this problem, dynamic model inversion based on the linearized model and Sigma-Phi neural network with adaptive weight update are involved to realize the waypoint following algorithm for the vehicle in the helicopter flight mode (nacelle angle=0 deg). This algorithms consists of two main parts: outer-loop system as a command generator and inner-loop system as stabilizing controller. In this waypoint following problem, the position information in the inertial axis is given to the outer-loop system. From this information, Attitude Command/Attitude Hold logic in the longitudinal channel and Rate Command/Attitude Hold logic in the lateral channel are realized in the inner-loop part of the overall structure of the waypoint following algorithm. The nonlinear simulation based on the TR-KUAV is carried out to evaluate the stability and performance of the algorithm. From the numerical simulation results, the algorithm shows very good tracking performance of passing the waypoints given. Especially, it is observed that ACAH/RCAH logic in the inner-loop has the satisfactory performance due to adaptive neural network in spite of the model error coming from the linear model based inversion.

• Journal of Mechanical Science and Technology
• /
• 제19권8호
• /
• pp.1529-1543
• /
• 2005

Recently an unmanned aerial vehicle (UAV) has been widely used for military and civil applications. The role of a navigation system in the UAV is to provide navigation data to the flight control computer (FCC) for guidance and control. Since performance of the FCC is highly reliant on the navigation data, a fault in the navigation system may lead to a disastrous failure of the whole UAV. Therefore, the navigation system should possess a fault detection and isolation (FDI) algorithm. This paper proposes an attitude determination GPS/INS integrated navigation system with an FDI algorithm for a UAV. Hardware for the proposed navigation system has been developed. The developed hardware comprises a commercial inertial measurement unit (IMU) and the integrated navigation package (INP) which includes an attitude determination GPS (ADGPS) receiver and a navigation computer unit (NCU). The navigation algorithm was implemented in a real-time operating system with a multi-tasking structure. To evaluate performance of the proposed navigation system, a flight test has been performed using a small aircraft. The test results show that the proposed navigation system can give accurate navigation results even in a high dynamic environment.

• 제어로봇시스템학회논문지
• /
• 제6권12호
• /
• pp.1120-1125
• /
• 2000

This paper presents a technique for estimating the attitude of a model helicopter at near hovering using a combination of inertial and non-inertial sensors such as gyroscope and potentiometer. To estimate the attitude of helicopter a simplified indirect Kalman filter based on sensor modeling is derived and the characteristics of sensors are studied, which are used in determining the optimal Kalman gain. To verify the effectiveness of the proposed algorithm simulation results are presented with real flight data. Our approach avoids a complex dynamic modeling of helicopter and allows for an elegant combination of various sensor data with different measurement frequencies. We also describe the method of implementation of the algorithm in the model helicopter.

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