• 항공우주시스템공학회지
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• 제12권1호
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• pp.27-34
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• 2018

CMG의 발생 토크는 김블의 각속도에 비례하고 위성의 자세제어에 직접적인 영향을 미치기 때문에 김블의 토크 리플 저감이 필요하다. 본 논문에서는 토크 리플의 발생 원인을 베어링에 의한 마찰 불균형, 모터의 자기장과 상전류 불균형으로 가정하여 이를 수학적으로 모델링한다. 김블의 정속 구동 데이터를 통해 모델링의 파라미터를 추정하고 이를 이용하여 피드포워드 제어로 적용할 경우 영향성을 분석한다. 시뮬레이션을 통해 토크 리플과 각속도 변동이 저감되는 것을 확인하여 외란 모델링을 이용한 외란 저감 기법을 제시한다.

• 대한기계학회논문집A
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• 제29권5호
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• pp.743-753
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• 2005

The model of azimuth driving servo system with a flexible antenna in a prototype gimbal has been derived in this work. The validity of the model is verified by comparing the result of the model with that of experiment. It is found that one should consider an antenna as a flexible body in case of modeling the dynamics of the gimbal with an antenna. It is also known that the effect of reducing backlash magnitude for extending the bandwidth in the system with a flexible antenna is smaller than the system with a stiff antenna. It is thought that the model-based design optimization of the gimbal with an antenna will be possible by virtue of the derived model, when a weight reduction and a bandwidth extension are required.

• 융합신호처리학회논문지
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• 제14권2호
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• pp.117-123
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• 2013

서보 시스템에서 마찰과 같은 비선형 요소는 측정이 어려우며, 또한 정확한 예측이 어려워 보상하기가 쉽지 않다. 특히, 2축 안정화 짐벌 시스템에서 마찰은 큰 오차를 발생시켜 최종적으로 제어 성능을 만족시키지 못한다. 이와 같은 문제점을 해결하기 위해 관측기 등을 적용한 마찰 보상 연구가 많이 진행되어 왔으나 특정 조건에서만 적용되어 군수 분야에서 정밀도를 요하는 2축 안정화 짐벌 시스템에 적용하는데 제한적이다. 본 논문에서는 가장 일반적이면서 강인성이 입증된 PID 알고리즘을 변형시킨 PI-LEAD 알고리즘을 사용하여 모델링 및 시뮬레이션을 통해 마찰 보상 효과를 입증하고, 실제 2축 안정화 짐벌 시스템에 적용하여 효과를 검증한다. 성능시험을 통해 PI-LEAD 알고리즘이 마찰에 의한 오차를 최소화하여 정밀 서보 시스템에서 요구하는 성능을 만족하는 것을 검증하였다.

• 전기학회논문지
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• 제60권12호
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• pp.2386-2391
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• 2011

Tracking and detecting targets by the millimeter wave seeker is affected by moving of platform. In order to perform the tracking performance, stabilization of a millimeter wave seeker which consists of 2-axis gimbals was considered in this study. The feasibility of the analysis and the 2-axis gimbal servo system modeling design were verified along with some simulation results.

• 제어로봇시스템학회논문지
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• 제7권1호
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• pp.1155-1161
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• 2001

We propose an adaptive nonlinear control algorithm for high precision tracking and stabilization of LOS(Line-of-Sight). The friction parameters of the LOS gimbal are estimated by off-line evolutionary strategy and the friction is compensated by estimated friction compensator. Especially, as the nonlinear control input in a small tracking error zone is enlarged by the nonlinear function, the steady state error is significantly reduced. The proposed algorithm is a direct adaptive control method based on the Lyapunov stability theory, and its convergence is guaranteed under the limited modeling error or torque disturbance. The performance of the pro-posed algorithm is verified by computer simulation on the LOS gimbal model of a moving vehicle.

• 제어로봇시스템학회논문지
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• 제9권3호
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• pp.204-209
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• 2003

The line-of-sight stabilization system is an equipment which is loaded on a vehicle and stabilizes the direction of the line-of-sight of the vision sensor to obtain a not-swayed image in the existence of external disturbances. To obtain accurate Euler angles and angular velocities simultaneously we usually need a control system which uses high-price inertial sensors including Vertical Gyro(VG) or Rate Integrating Gyro(RIG). In this paper, we design and implement a control system of a gimbal, which is a line-of-sight stabilization system using a low-cost mixed algorithm of a rate gyro and an accelerometer instead of a VG and a RIG. In the experiment where we laid the implemented line-of-sight stabilization system on the rate table. we can see the stabilized performance to external disturbances.

• 한국군사과학기술학회지
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• 제2권2호
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• pp.226-233
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• 1999

A transmitting antenna mounted on the naval vessels can be easily exited by exogenous disturbances such as wave and impact. Gimbal system need for the controller to maintain the robust performance against various modeling uncertainties and disturbances. PI controller, however, cannot supply good robust performance under situation. Thus a robust $H_{\infty}$ control scheme is used to ensure a specified dynamic response under above conditions. Gimbal system controlled simplified as 2 DOF system that ignored coordinate co-relations of each direction and hydraulic system is linearly modelled. In this paper, we compared those of simulation to the results of experiment and H$_{\infty}$ controller, proposed, showed the good response and stability than PI controller.

• 항공우주시스템공학회지
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• 제13권3호
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• pp.1-8
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• 2019

전자기적 힘에 의해 김블 모터에 토크가 발생하며 코일 전류 변화는 토크 리플을 야기한다. 이는 김블속도에 영향을 주는 동시에 위성의 자세를 불안정하게 한다. 따라서 위성의 자세 제어 정확도 향상을 위해서는 김블 모터의 토크 리플 저감이 필수적이다. 본 논문에서는 일반적인 집중형 권선과 분포형 권선에 대해 모터의 모델링으로부터 발생 토크를 이론적으로 시뮬레이션 분석하였다. 토크 리플을 저감하는 권선을 선정하여 시제품을 설계 및 제작하여 자기장 및 역기전력의 이론적 해석 결과와 측정 결과를 비교하여 설계와 제작의 합치성을 확인하였다. 저속 시험을 통해 전절권 분포형 권선의 속도 안정도가 향상되어 토크 리플이 저감됨을 입증하였다.

• 한국소음진동공학회논문집
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• 제22권3호
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• pp.284-290
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• 2012

In this research, a new type of haptic master device using electrorheological(ER) fluid for minimally invasive surgery(MIS) is devised and control performance of the proposed haptic master is evaluated. The proposed haptic master consists of ER bi-directional clutch/brake for 2 DOF rotational motion(X, Y) using gimbal structure and ER brake on the gripper for 1 DOF rotational motion (Z). Using Bingham characteristic of ER fluid and geometrical constraints, principal design variables of the haptic master are determined. Then, the generation of torque of the proposed master is experimentally evaluated as a function of applied field of voltage. A sliding mode controller which is robust to uncertainties is then designed and empirically realized. It has been demonstrated via experiment that the proposed haptic master associated with the controller can be effectively applied to MIS in real field conditions.

• International Journal of Precision Engineering and Manufacturing
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• 제3권4호
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• pp.78-86
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• 2002

In this paper, LMI (Linear Matrix Inequality) based on H$\_$$\infty$/ controller for a lire of sight (LOS) stabilization system. It shows that the proposed controller has more excellent stabilization performance than that of the conventional PI-Lead controller. An H$\_$$\infty$/ control has been also applied to the system for reducing modeling errors and the settling time of the system. The LMI-based H$\_$$\infty$/ controller design is more practical in view of reducing a run-time than Riccati-based H$\_$$\infty$/ controller. This H$\_$$\infty$/ controller is available not only to decrease the gain in PI-Lead control, but also to compensate the identifications for the various uncertain parameters. Therefore, this paper, shows that the proposed LMI-based H$\_$$\infty$/ controller had good disturbance attenuation and reference input tracking performance compared with the control performance of the conventional controller under any real disturbances.