• Title, Summary, Keyword: Gimbal

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Vibration Characteristic Analysis Of Gimbal Structure in Collection Equipment of Image Information (영상정보 수집 장치용 짐발 구조물의 진동특성해석)

  • Lee, Sang-Eun;Lee, Tac-Won
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.9 no.2
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    • pp.20-25
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    • 2010
  • A camera module is supported by a gimbal structure in collection equipment of image information. During flight, the gimbal system undergoes serious accelerations with wide frequencies. To get the correct images, the camera module must be stably vibrated under these conditions. If natural frequency unfortunately exists in a exciting frequency range, resonance occurs there. Hence, harmonic responses analysis is needed to know correct vibration characteristic of the gimbal system. Finite element analysis was performed to get an acceleration of the gimbal system by mode superposition after extracting mode shapes and natural frequencies. Considering damping ratio of 2%, the reponses of gimbal structure were calculated from excitations with a design frequency band. As results, a maximum acceleration transmissibility, which is the ratio of response to excitation, was obtained and it can be used to design the gimbal structure effectively.

A Precision Position Control of Antenna Driving System in Naval Vessel (함상 안테나 구동용 안정화장치의 정밀 위치제어)

  • Cho, Taik-Dong;Seo, Song-Ho;Nam, Ki-Jung
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.4
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    • pp.190-196
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    • 2001
  • The naval vessel must moves rolling, pitching, yawing by wave when it runs in ocean. Some narrow beam antenna needed position compensation by stabilizer or gimbal for best performance. This paper presents the precision position control for heavy weight(130kg) in roll and pitch direction. Generally it's called for gimbal. This gimbal uses P-I controller, and it's driven by linear actuator and servo motor. This gimbal gets ship's gyro signal and synchro, which have the absolute angle value. Some other similar equipments are driven by huge hydraulic power, but this gimbal is driven by small servo motor. This control loop gets the following procedure repeatedly; reading ship gyro and gimbal synchro, calculating compensated error and control output, driving motor and actuator The performance of gimbal system was satisfied.

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Delay Dependent Fuzzy H Control of Radar Gimbal Stabilization System with Parameter Uncertainty and Time Delay (파라미터 불확실성 및 시간지연을 갖는 레이더 김벌 안정화 시스템의 지연종속 퍼지 H 제에)

  • Kim, Tae-Sik;Lee, Hae-Chang;Lee, Kap-Rai
    • Journal of Institute of Control, Robotics and Systems
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    • v.11 no.11
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    • pp.920-929
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    • 2005
  • This paper presents controller design method for nonlinear radar gimbal system with parameter uncertainty and time delay. In order to consider nonlinearity of gimbal bearing frictional torque, we firstly represent fuzzy model for the nonlinear gimbal system, which is achieved by fuzzy combination of linear models through nonlinear fuzzy membership functions. And secondly we propose a delay dependent fuzzy $H_\infty$ controller design method for the delayed fuzzy model with parameter uncertainty and design radar gimbal controller. The designed controller stabilize gimbal system and guarantee $H_\infty$ performance. A computer simulation is given to illustrate stabilized control performances of the designed controller.

Vibration Analysis for Gimbal Structure of a Micro Wave Seeker(II) : Finite Element Analysis (마이크로 웨이브 탐색기의 김발 구조물 진동해석(II) : 유한요소해석)

  • Chang, Young-Bae;Jun, Hong-Gul;Lee, Sock-Kyu;Youn, Jae-Youn;Park, Young-Pil
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.514-518
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    • 2000
  • Micro wave seeker consists of a gimbal structure, a antenna and many RF parts. And Missile's propelling powers excite a gimbal structure, a antenna and many RF parts. Therefore, We must inquire into external forces to act on a micro wave seeker before everything. We must inquire into design parameters and then estimate dynamic characteristics of a gimbal structure with a finite element model to reflect part's characteristics for design for a gimbal structure in consideration of vibration features. In this paper, a gimbal structure of a micro wave seeker is modeled in finite element method and then updated by using the experimental modal data. Before we make a finite element model of a gimbal structure of a micro wave seeker, we make a finite element model of a sub-structure and compare with the experimental modal data.

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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
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    • v.67 no.10
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    • pp.1395-1400
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    • 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.

Vibration Analysis for a Gimbal Structure of a Micro Wave Seeker(I) : Experimental Modal Analysis (마이크로 웨이브 탐색기의 김발 구조물 진동해석(I) : 실험모드해석)

  • Lee, Sock-Kyu;Chang, Young-Bae;Lee, Jin-Koo;Kwon, Byung-Hyun;Park, Young-Pil
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.508-513
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    • 2000
  • Micro wave seeker detects micro wave signal reflecting from a object and modifies the angle of a antenna in the direction of a reflecting signal. Gimbal structure makes a motion in the direction of an elevation axis and an azimuth axis and change the direction of a missile toward a object. As before, Micro wave seeker is a important part of a missile. Especially, gimbal structure is designed to resist a external force generated by a strong propelling power. For that reason, it is essential to analyze a vibration feature of gimbal structure. In this paper, we analyze dynamic characteristics of a gimbal structure of a micro wave seeker. And we measure frequency response functions of a gimbal structure in order to investigate the effect of a pre-load on bearing.

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An Antenna Tracking Profile Design for Communication with a Ground station

  • Lee, Donghun;Lee, Kyung-Min;Rashed, Mohammed Irfan;Bang, Hyochoong
    • International Journal of Aeronautical and Space Sciences
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    • v.14 no.3
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    • pp.282-295
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    • 2013
  • In order to communicate with a ground station, the tracking profile design problem for a directional antenna system is considered. Because the motions of the gimbal angles in the antenna system affect the image quality, the main object is to minimize the motion of the gimbal angles during the satellite's imaging phase. For this goal, parameter optimization problems in the imaging and maneuver phases are formulated separately in the body-frame, and solved sequentially. Also, several mechanical constraints, such as the limitation of the gimbal angle and rate, are considered in the problems. The tracking profiles of the gimbal angles in the maneuver phases are designed with N-th order polynomials, to continuously connect the tracking profiles between two imaging phases. The results confirm that if the vector trace of the desired antenna-pointing vector is within the antenna's beam-width angle, motions of the gimbal angles are not required in the corresponding imaging phase. Also, through numerical examples, it is shown that motion of the gimbal angles in the imaging phase can be minimized by the proposed design process.

A Simultaneous Experimental Disturbances Identification of Gyro Stabilized 2-Axes Gimbal System for Disturbance Feedforward Compensation Control (2-축 자이로 안정화 김발 시스템의 외란보상 앞먹임 제어를 위한 실험적 2-축 외란 동시 식별)

  • Yeo, Sung Min;Kang, Min Sig
    • Journal of the Korea Institute of Military Science and Technology
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    • v.21 no.4
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    • pp.508-519
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    • 2018
  • This paper concerns on stabilization control of a gyro-stabilized 2-axes gimbal system which is mounted on a moving vehicles such as automobiles, armored vehicles, ships, flying vehicles, etc. A target image acquisition system is attached on the inner gimbal, and the gimbal systems are required to retain high stabilization accuracy in the absolute coordinate in order to provide fine target image while vehicle is moving. The stabilization control performance is hardly depended upon disturbance rejection ability of control, and disturbance feedforward compensation is effective because feedforward compensation reduce the amount of disturbance before the disturbance disturbs the systems. This paper suggests an experimental method which can estimate system parameters and disturbance torques by using 3-axes accelerometer mounted on the inner gimbal. Furthermore, a simple disturbance identification method which can be applied to any slanted base conditions has been suggested to identify mass unbalance vector and friction torques of each gimbal simultaneously. By using the estimated parameters, a feedforward compensation has been applied to the gyro-stabilized 2-axes gimbal system. The experimental results showed that the feedforward compensation based on the identification method suggested is effective to improve stabilization performances.

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
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    • v.67 no.11
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    • pp.1555-1561
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    • 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.

The simulation of INS error due to gimbal servo dynamics (김블 서어보 다이나믹스에 의한 INS 오차 시뮬레이션)

  • 김현백;정태호;오문수
    • 제어로봇시스템학회:학술대회논문집
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    • pp.281-285
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    • 1986
  • In this paper, the characteristics of disturbance torque of gimbal servo dynamics are studied, and the simulation methods of gimbal servo dynamics and INS error due to angular rate and linear acceleration of vehicle are proposed. In results of the simulation for a specific INS, it is estimated that INS velocity error due to gimbal servo dynamics is nearly proportional to square of vehicle acceleration.

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