• Title/Summary/Keyword: Gimbals

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Gravity Compensator for the Roll-pitch Rotation (Roll-pitch 중력 보상 기구 설계)

  • Cho, Chang-Hyun;Lee, Woo-Sub;Kang, Sung-Chul
    • Journal of Institute of Control, Robotics and Systems
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    • v.16 no.7
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    • pp.688-694
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    • 2010
  • This paper presents a gravity compensator for the manipulator of a service robot. The manipulator of a service robot is operated with low velocity for the safety reason in most cases. In this situation gravitational torques generated by the mass of links are often much greater than dynamic torques for motion. A gravity compensator can counterbalance the gravitational torques, thereby enabling to utilize relatively low power motors. In this paper the gravity compensation for the roll-pitch rotation is considered which is often used for the shoulder joints of the manipulator of a service robot or humanoid robot. A gimbals is implemented and two 1-dof gravity compensators are equipped at the base. One compensates the gravitational torque at the roll joint and another provides the compensational torque for the gimbals. Various analyses showed that the proposed compensator can counterbalance the gravitational torques of 87% at the pitch joint and 50% at the roll joint. It is verified from dynamic simulations that the proposed compensator effectively counterbalances the gravitational torques.

Satellite Attitude Control Using Optimal Control Law (최적제어 기법을 이용한 위성의 자세제어)

  • 양재윤;박수홍;조겸래
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.395-400
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    • 1991
  • In spinning satellite, a gyrotorquer generates a control torquer along two orthogonal axes normal to the spin axis of the vehicle. Matrix Fraction Description(MFD) are used to obtain minimal realization of the transfer matrix relating the attitude angles and the rate of rotation of the gimbals of gyrotorquer. In this paper, the Linear Quadratic Gaussian with Loop Transfer Recovery and H.meihodologies are used to design controller for spinning satellite.

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Measurements Coastal landfill Using Automatic VRS-GPS Surveying (VRS-GPS 자동측위시스템을 이용한 해안매립지 측량)

  • Nam, Kwang-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.10
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    • pp.5215-5220
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    • 2013
  • Recent construction in the field of 3D aversion is increasing interest in automation. This study is results about survey of the coastal landfill using automatic VRS-GPS surveying system. GPS is made with GRXI and SHC250 controller. Automatic surveying system is composed of DPS module, geomagnetism sensor, bluetooth, gimbals, IMU, etc and enables an automatic driving via entered into a route of position. The developed auto surveying system has installed the front and camera for vertical axis and can grasp situation of surveying with smartphone in real time. The comparative result between surveyed result with repetition method auto VRS-GPS surveying system observed surveyed result with VRS-RTK has shown that average error of x-axis is 0.009m, average error of y-axis, 0.010m and average error of height, 0.002m. This possibility was confirmed that field application.

Attitude Estimation of Agricultural Unmanned Helicopters using Inertial Measurement Sensors (관성센서를 이용한 농용 무인 헬리콥터의 자세 추정)

  • Bae, Yeonghwan;Oh, Minseok;Koo, Young Mo
    • Current Research on Agriculture and Life Sciences
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    • v.32 no.3
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    • pp.159-163
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    • 2014
  • Agricultural unmanned helicopters have become a new paradigm for aerial application. Yet, such agricultural helicopters require easy and affordable attitude control systems. Therefore, this study presents an affordable attitude measurement system using a DCM (direction cosine matrix) algorithm that would be applied to agricultural unmanned helicopters. An IMU using a low-cost MEMS and an algorithm to estimate the attitude of the helicopter were applied in a gimbals structure to evaluate the accuracy of the attitude measurements. The estimation errors in the attitude were determined in comparison with the true angles determined by absolute position encoders. The DCM algorithm and sensors showed an accuracy of about 1.1% for the roll and pitch angle estimation. However, the accuracy of the yaw angle estimation at 3.7% was relatively larger. Such errors may be due to the magnetic field of the stepping motor and encoder system. Notwithstanding, since the intrinsic behavior of the agricultural helicopter remains steady, the determination of attitude would be reliable and practical.

Development of Servo for Small Tracking Radars (소형 추적 레이다용 서보 개발)

  • Lee, Jong-Kuk;Lee, Seok-In;Kim, Jun-Su;Song, Tae-Seong;Eom, Young-Cheol;Ahn, Se-Hwan;Shin, Yu-Jin;Joo, Ji-han;Kwon, Jun-Beom;Kim, Sang-Wook
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.22 no.6
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    • pp.21-30
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    • 2022
  • This paper describes the design, manufacture, and testing of servos applicable to small tracking radars. First, Chapter 1 describes the necessity of this study. Chapter 2 describes the development of servos applicable to future tracking radars in small missile systems. Chapter 3 describes the design and test results for current control of brushed DC motors, brushless DC motors, and permanent magnet synchronous motors. And Chapter 4 describes the design and test results for speed control of the test wheel. And in Chapter 5, the results of the previous tests are summarized. In this paper, some pictures were intentionally blurred for security reasons, and the control result of test wheel was described, not the test with the developed gimbals.

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
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    • v.60 no.12
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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.

A Study on Visual Servoing Image Information for Stabilization of Line-of-Sight of Unmanned Helicopter (무인헬기의 시선안정화를 위한 시각제어용 영상정보에 관한 연구)

  • 신준영;이현정;이민철
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.600-603
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    • 2004
  • UAV (Unmanned Aerial Vehicle) is an aerial vehicle that can accomplish the mission without pilot. UAV was developed for a military purpose such as a reconnaissance in an early stage. Nowadays usage of UAV expands into a various field of civil industry such as a drawing a map, broadcasting, observation of environment. These UAV, need vision system to offer accurate information to person who manages on ground and to control the UAV itself. Especially LOS(Line-of-Sight) system wants to precisely control direction of system which wants to tracking object using vision sensor like an CCD camera, so it is very important in vision system. In this paper, we propose a method to recognize object from image which is acquired from camera mounted on gimbals and offer information of displacement between center of monitor and center of object.

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Development of New-Type Mechanical Gyrocompass for Ship (새로운 형식의 선박용 기계식 자이로콤파스의 개발에 관한 연구)

  • Choi, Woo-Jin;Bae, Jung-Chul;Lee, Joon-Tark
    • Proceedings of the KIEE Conference
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    • 1999.07b
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    • pp.553-555
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    • 1999
  • In this paper, we developed the new-type digital gyrocompass for ship. This is made of DTG(Dynamically Tuned Gyro) and two accelerometers. The simple structure of two-axis free gimbals and the digital precession by CPU unit are main differences from Sperry or Anschutz type gyrocompass. As experimental results, the developed gyrocompass seeks the true north within 1 hour and support maximum speed 100[knot], maximum latitude $75[^{\circ}]NS$. By the comparison with other company's Products, we show the uniqueness and the excellence of the proposed gyrocompass.

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Stabilization Loop Design Method on Dynamic Platform

  • Kwon, Young-Shin;Kim, Doh-Hyun;Kim, Lee-Han;Hwang, Hong-Yeon
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.156.5-156
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    • 2001
  • Stabilized tracking platform in a missile consisting of a flat planar antenna, pitch/yaw gimbals, gear trains, and current controlled DC drive motors for pitch and yaw gimbal must have a capability to track a target as an inertial sensor in the presence of missile body motion such as maneuvering and vibration. Because of this reason, tracking a target from dynamic platform requires a servo architecture that includes a outer tracking loop(position loop) and inner rate loop that stabilizes the line of sight(LOS). This paper presents a gimbaled platform model including nonlinear phenomena due to viscous and Coulomb friction based on experimental data and torque equilibrium equation, the design concept for the inner tacholoop having P controller structure ...

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Development of the Scaled Vehicle of Smart UAV (스마트무인기 축소형 비행체 개발)

  • Chang, Sung-Ho;Choi, Seong-Wook;Koo, Sam-Ok
    • Aerospace Engineering and Technology
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    • v.6 no.2
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    • pp.236-244
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    • 2007
  • The 40% scaled vehicle of Smart UAV has been developed for the investigation of basic flight characteristics and the verification of flight control algorithm. The similar gimbal hub and drive train with the full scale UAV were implemented and a forced air cooling reciprocating engine was installed. The various kind of tests were conducted for the major components of the vehicle. The important performance and mechanical endurance of the fabricated vehicle were identified by ground and hovering test.

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