• Title/Summary/Keyword: LOS stabilization gimbal

Search Result 12, Processing Time 0.027 seconds

Analysis of Line of Sight Stabilization Performance based on Direct vs. Indirect of a 2-axis Gimbaled Servo System for Millimeter Wave Seeker (밀리미터파 탐색기 2축 직구동 김발 서보 시스템의 직접 및 간접 시선안정화 성능 분석)

  • Shin, Seungchul;Lee, Sung-Yong
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.67 no.11
    • /
    • pp.1555-1561
    • /
    • 2018
  • Tracking and detecting targets by the millimeter wave seeker is affected by movement of platform. Stabilization equipments use an inertial sensor to compensate for disturbance of stabilizing gimbal or platform. In the direct line of sight stabilization system, an inertial sensor is mounted on inner gimbal to compensate the disturbance directly, so the performance is excellent and the implementation method is simple. However gimbal design requires somewhat larger volume. Since an inertial sensor is mounted on gimbal base in the indirect line of sight stabilization system, additional space of gimbal is not required for the gimbal design. However, this method does not directly compensate for the disturbance of the line of sight stabilization axis, which can degrade performance. In order to perform the tracking performance, two methods are analyzed for line of sight stabilization performance based on direct and indirect of a 2-axis gimbaled servo system for millimeter wave seeker in this study. The simulation and experimental results validate the performance comparison of two methods.

LOS Moving Algorithm Design of Electro-Optical Targeting Pod for Joystick Command (조이스틱 명령에 따른 Electro-Optical Targeting Pod의 LOS 이동 알고리즘 설계)

  • Seo, Hyoungkyu;Park, Jaeyoung;Ahn, Jung-Hun
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.67 no.10
    • /
    • pp.1395-1400
    • /
    • 2018
  • EO TGP(Electro-Optical Targeting Pod) is an optical tracking system which has various functions such as target tracking and image stabilization and LOS(Line of Sight) change. Especially, it is very important to move the LOS into a interest point for joystick command. When pilot move joystick in order to observe different scene, EO TGP gimbals should be operated properly. Generally, most EOTS just operate corresponding gimbal for joystick command. For example, if pilot input horizontal command in order to observe right hand screen, it just drive azimuth gimbal at any position. But in the screen, the image dosen't move in a horizontal direction because gimbal structure is Euler angle. And image rotation is occurred by elevation gimbal angle. So we need to move Pitch gimbal. So in the paper, we designed LOS moving algorithm which convert LOS command to gimbal velocity command to move LOS properly. We modeled a differential kinematic equation and then change the joystick command into velocity command of gimbals. This algorithm generate velocity command of each gimbal for same horizontal direction command. Finally, we verified performance through MATLAB/Simulink.

LOS(line-of-sight) Stabilization Control of OTM(on-the-move) Antenna Driven by Geared Flexible Transmission Mechanism (기어와 유연축을 갖는 구동계로 구동되는 OTM 안테나 시선의 안정화 제어)

  • Kang, Min-Sig;Yoon, Wo-Hyun;Lee, Jong-Bee
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.21 no.10
    • /
    • pp.951-959
    • /
    • 2011
  • In this study, an OTM(on-the-move) antenna which is mounted on ground vehicles and is used for mobile communication between vehicle and satellite while moving was addressed. Since LOS(line-of-sight) of antenna should direct satellite consistently while vehicle moving to guarantee high satellite communication quality, active antenna LOS stabilization is a core technology for OTM antenna. Stabilization of a satellite tracking antenna which consists of 2-DOF gimbals, an elevation gimbal over an azimuth gimbal, was considered in this study. In consideration of driving mechanism which consists of gear train and flexible driving shafts, a two-mass-system dynamic model coupled with vehicle motion was presented. An internal PI-control loop + outer PI-control loop structure has been suggested in order to damp the torsional vibration and stabilize control system. The classical pole-placement method was applied to design control gains. In addition, a vehicle motion compensation control beside of the feedback control loop has been suggested to improve LOS stabilization performances. The feasibility of the proposed control design was verified along with some experimental results.

Adaptive High Precision Control of Lime-of Sight Stabilization System (시선 안정화 시스템의 고 정밀 적응제어)

  • Jeon, Byeong-Gyun;Jeon, Gi-Jun
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.7 no.1
    • /
    • pp.1155-1161
    • /
    • 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.

  • PDF

Vibration suppression control based on model reference approach for LOS stabilization gimbal (모델 참조 제어 방법에 의한 시선 안정화 짐발의 공진 제어)

  • Ma, Jin-Suk;Kang, Myong-Sook;Kwon, Woo-Hyen
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.5 no.5
    • /
    • pp.540-549
    • /
    • 1999
  • In this paper, the vibration suppression scheme based on a model referece approach is proposed. The vibration results from the coupling of the system and its frequency are given by the mechanical factors. In the proposed scheme, a low frequency vibration mode is transferred to high one. And also its damping ratio can be increased without any mechanical redesign. Therefore, bandwidth and open loop gain of the plant are increased and the performance of the system can be improved. This paper analyzes the proposed vibration suppression scheme, which is compared with the conventional control scheme for mechanical resonance suppression. For proving the realistic validity, we apply the proposed scheme to a LOS(Line Of Sight) stabilization system which has vibration effect. Finally, the proposed scheme is verified through simulations and experiments.

  • PDF

Real-time Unbalance Moment Compensation Method for Line of Sight(LOS) Stabilization Control System (시선안정화 제어시스템의 실시간 불균형 모멘트 보상기법)

  • Jo, Sihun
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.26 no.3
    • /
    • pp.323-330
    • /
    • 2016
  • This paper describes real-time unbalance moment compensation method for line of sight(LOS) stabilization control systems. The factors of system inertia, frictions and unbalance moment affect the control accuracy of drive systems that are equipped to on the move(OTM) platforms requiring LOS stabilization function. In case of the unbalance moment among those factors is continuously changed as variation of relative angle between gravity vector and drive torque vector. Then, consideration of the effect in real-time is very complicate. Therefore, its effect should be designed to be minimized, however, designing it almost zero is impossible in real condition. In other words, it is hard to achieve target performance overcoming stability issue of highly unbalanced systems. To solve these problems, this paper proposes calculation method of unbalance moment by using measured sensor data for LOS stabilization control and its use for control compensation. Also, kinematical converting process and control structure for compensation are explained. The effectiveness of the proposed method as variation of unbalance moment is verified under simulation circumstance modeled by assuming LOS control system with 2-axis gimbal structure.

Robust Controller Design for a Stabilized Head Mirror

  • Keh, Joong-Eup;Lee, Man-Hyung
    • International Journal of Precision Engineering and Manufacturing
    • /
    • v.3 no.4
    • /
    • pp.78-86
    • /
    • 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.

Stabilization Control of line of sight of OTM(On-The-Move) Antenna (OTM 단말기 안테나 시선 안정화 제어)

  • Kang, Min-Sig;Cho, Yong-Wan
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.59 no.11
    • /
    • pp.2073-2082
    • /
    • 2010
  • The 4-th generation of mobile communication aims to realize global, fast and mobile communication service. The satellite communication charges a key role in this field. In this study, an OTM(On-The-Move) antenna which is mounted on ground vehicles and is used for mobile communication between vehicle and satellite was addressed. Since vehicles move during communication, active antenna line-of-sight stabilization is a core technology to guarantee high satellite communication quality. Stabilization of a satellite tracking antenna which consists of 2-DOF gimbals, an elevation gimbal over an azimuth gimbal, was considered in this study. Various disturbance torques such as static and dynamic mass imbalance torques, variation of moment of inertia according to elevation angle, friction torque related to vehicle motion, equivalent disturbance torque due to antenna roll motion, etc. were analyzed. As a robust stabilization control, rate feedback with sliding mode control and position feedback with proportional+integral control was suggested. To compensate antenna roll motion, a supplementary roll rate feed forward control was included beside of the feedback control loop. The feasibility of the analysis and the proposed control design were verified along with some simulation results.

A Control for 2-axis Gimbaled Millimeter Wave Seeker using Space Vector PWM of PMSM (영구 자석형 동기전동기의 공간전압벡터 PWM 기법을 적용한 밀리미터 웨이브 탐색기 2축 김발 구동 제어)

  • Lee, Sung-Yong;Lee, Jung-Suk
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.60 no.12
    • /
    • pp.2386-2391
    • /
    • 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.

An Adaptive Filtering Technique for Vibration Reduction of a Rotational LOS Control System and Frequency Noise Reduction of an Imaging System (적응형 필터링 기법을 이용한 회전형 시선제어시스템의 진동 저감 및 영상 주파수노이즈 저감 기법)

  • Kim, Byeong-Hak;Kim, Min-Young
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.20 no.10
    • /
    • pp.1014-1022
    • /
    • 2014
  • In mechatronic systems using electric signals to drive control systems, driving signals including the frequency band of the unwanted signals, such as resonant frequencies and noise frequencies, can affect the accuracy of the controlled system and can cause serious damage to the system due to the resonance phenomenon of the mechatronic system. An LOS (Line of Sight) control unit is used to automatically rotate the gimbal system with a video imaging system generally mounted on modern aerial vehicles. However, it still suffers from natural frequency variation problems due to variations of operational temperature. To prevent degradation in performance, this paper proposes an adaptive filtering technique based on real-time noise analysis and adaptive notch-filtering for LOS control systems, and verifies how our proposed method maintains the LOS stabilization performance. Additionally, this filtering technique can be applied to the image noise filtering of the video imaging system. It is designed to reduce image noises generated by switching circuits or power sources. The details of design procedures of the proposed filtering technique and the experiments for the performance verification are described in this paper.