• Title/Summary/Keyword: Position error equation

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A Study on the Error Compensation of Three-DOF Translational Parallel Manipulator (3자유도 병렬기구의 위치오차 보정기술에 관한 연구)

  • 신욱진;조남규
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.3
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    • pp.44-52
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    • 2004
  • This paper proposed a error compensation methodology for three-DOF translational parallel manipulator. The proposed method uses CMM (coordinate measuring machine) as metrology equipment to measure the position of end-effector. To identify the transform relationships between the coordinate system of the parallel manipulator and the CMM coordinate system, a new coordinate referencing (or coordinate system identification) technique is presented. By using this technique, accurate coordinate transformation relationships are efficiently established. According to these coordinate transformation relationships, an equation to calculate the compensating error components at any arbitrary position of the end-effector is derived. In this paper, Monte Carlo simulation method is applied to simulate the compensation process. Through the simulation results, the proposed error compensation method proves its effectiveness and feasibility.

Analysis of Estimated Position Error by Magnetic Saturation and Compensating Method for Sensorless Control of PMSM (자속 포화에 의한 PMSM 센서리스 위치 추정 오차 분석 및 보상 기법)

  • Park, Byung-Jun;Gu, Bon-Gwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.68 no.3
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    • pp.430-438
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    • 2019
  • For a pump or a compressor motor, a high periodic load torque variation is induced by the mechanical works, and it causes system vibration and noise. To minimize these problems, load torque compensation method, injecting periodic torque current, could be utilized. However, with the sensorless control method, which is usually utilized in the pump and compressor for low cost, the periodic torque current degrades the accuracy of the rotor position estimation owing to the inductance variation. This paper analyzes the rotor position and speed estimation error of sensorless control method with constant motor parameters under period loading. Assuming the constant speed by the accurate load torque compensation, the speed error equation is derived in frequency domain with inductance depending on the stator current. Further, it is also shown that the rotor position error could be minimized by compensating the inductance variation. The simulation and experimental results verify that the derived speed error model and the validity of the inductance compensation method.

A Simplified Analysis Approach on the Rotor Position Detection Error in Sensorless Interior Permanent Magnet Brushless DC Motor Drives (센서리스 매입형 영구자석 브러시리스 직류전동기 구동장치에서 단순화된 회전자 위치검출 오차 분석 방법)

  • Lee, Kwang-Woon;Park, Tae-Sik
    • The Transactions of the Korean Institute of Power Electronics
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    • v.21 no.5
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    • pp.449-452
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    • 2016
  • This paper presents a simplified analysis on the rotor position detection error in sensorless interior permanent magnet brushless DC motor (BLDCM) drives, wherein terminal voltage sensing based on the back-electromotive force (back-EMF) zero-crossing point detecting circuitry is employed. The effect of a rotor saliency on the back-EMF's zero-crossing point detection is analyzed using the extended EMF-based voltage equation of the interior permanent BLDCM in a stationary reference frame, and thus the overall analysis is considerably simplified compared to the conventional one. Simulation results are provided to verify the effectiveness of the proposed method.

Orthogonalization principle for hybrid control of robot arms under geometric constraint

  • Arimoto, Suguru
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10b
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    • pp.1-6
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    • 1992
  • A principle of "orthogonalization" is proposed as an extended notion of hybrid (force and position) control for robot manipulators under geometric endpoint constraints. The principle realizes the hybrid control in a strict sense by letting position and velocity feedback signals be orthogonal in joint space to the contact force vector whose components are exerted at corresponding joints. This orthogonalization is executed via a projection matrix computed in real-time from a gradient of the equation of the surface in joint coordinates and hence both projected position and velocity feedback signals become perpendicular to the force vector that is normal to the surface at the contact point in joint space. To show the important role of the principle in control of robot manipulators, three basic problems are analyzed, the first is a hybrid trajectory tracking problem by means of a "modified hybrid computed torque method", the second is a model-based adaptive control problem for robot manipulators under geometric endpoint constraints, and the third is an iterative learning control problem. It is shown that the passivity of residual error dynamics of robots follows from the orthogonalization principle and it plays a crucial role in convergence properties of both positional and force error signals.force error signals.

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Design of the Estimator of Forward Kinematics Solution for a 6 DOF Motion Bed (6자유도 운동재현용 베드의 순기구학 추정기 설계)

  • 강지윤;김동환;이교일
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.04a
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    • pp.483-487
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    • 1996
  • We consider the estimation of the position and orientation of 6 DOF motion bed (Stewart platform) from the measured cylinder length. The solution of forward kinematics is not solved yet as a useful realtime application tool because of the complity of the equation with multiple solutiple solutions. Hence we suggest an algorithm for the estimation of forward kinematics solution using Luenberger observer withnonlinear error correction term. The Luenberger observer withlinear model shows that the estimation error does not go to zero in steadystate due to the linearization error of the dynamic model. Hence the linear observer is modified using nonlinear measurement error equation and we prove thd practical stability of the estimation error dynamics of the proposed observer using lyapunov function.

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A Study on the Position Accuracy Improvement Applying the Rectangular Navigation in the Hyperbolic Navigation System Area. (쌍곡선항법시스템을 이용한 직각항법에 의한 측위정도 향상에 관한 연구)

  • 김우숙;김동일;정세모
    • Journal of the Korean Institute of Navigation
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    • v.13 no.1
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    • pp.1-10
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    • 1989
  • Nowadays Hyperbolic Navigation System-LORAN, DECCA, OMEGA, OMEGA-is available on the ocean, and Spherical Navigation System, GPS (Global Positioning System) is operated partially. Hyperbolic Navigation System has the blind area near the base line extention because divergence rate of hyperbola is infinite theoretically. The Position Accuracy is differ from the cross angle of LOP although each LOP has the same error of quantity. GDOP(Geometric Dilution of Precisoin) is used to estimate the position accuracy according to the cross angle of LOP and LOP error. Hyperbola and ellipse are crossed at right angle everywhere. Hyperbola and ellipse are used to LOP in Rectangular Navigation System. The equation calculating the GDOP of rectangular Navigation System is induced and GDOP diagram is completed in this paper. A scheme that can improve the position accuracy in the blind area of Hyperboic Navigation System using the Rectangular Navigation System is proposed through the computer simulation.

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Development and Application of High-resolution 3-D Volume PIV System by Cross-Correlation (해상도 3차원 상호상관 Volume PIV 시스템 개발 및 적용)

  • Kim Mi-Young;Choi Jang-Woon;Lee Hyun;Lee Young-Ho
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.507-510
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    • 2002
  • An algorithm of 3-D particle image velocimetry(3D-PIV) was developed for the measurement of 3-D velocity Held of complex flows. The measurement system consists of two or three CCD camera and one RGB image grabber. Flows size is $1500{\times}100{\times}180(mm)$, particle is Nylon12(1mm) and illuminator is Hollogen type lamp(100w). The stereo photogrammetry is adopted for the three dimensional geometrical mesurement of tracer particle. For the stereo-pair matching, the camera parameters should be decide in advance by a camera calibration. Camera parameter calculation equation is collinearity equation. In order to calculate the particle 3-D position based on the stereo photograrnrnetry, the eleven parameters of each camera should be obtained by the calibration of the camera. Epipolar line is used for stereo pair matching. The 3-D position of particle is calculated from the three camera parameters, centers of projection of the three cameras, and photographic coordinates of a particle, which is based on the collinear condition. To find velocity vector used 3-D position data of the first frame and the second frame. To extract error vector applied continuity equation. This study developed of various 3D-PIV animation technique.

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High Precision Solenoid Type Nuclear Reactor Control Rod Position Indicator (고정밀도 솔레노이드 방식의 원자로 제어봉 위치지시기)

  • Baek, Min-Ho;Hong, Hoon-Bin;Park, Hee-June
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.11
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    • pp.1848-1853
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    • 2016
  • Control Rod Position Indicator in nuclear reactor vessel has developed for small reactor in Korea. Because of severe environment in reactor vessel, target of this study is to develop the suitable position indicator. In this study, solenoid type position indicator made of Mineral Insulated Cable(MI Cable) was introduced to adapt in severe environment. And inductance of the solenoid was used to indicate the rod position for high precision. But problem of this concept is that a linear slope of inductance is changed by temperature effect. To resolve this problem, two sensing coils were introduced for temperature compensation. A role of the sensing coil is to make reference linear equation about certain temperature. To confirm this concept, also, inductance of solenoid and sensing coils were measured at room and high temperature (${\sim}300^{\circ}C$). The results of measurement show that the position error of sensing coil between room and high temperature was about 2%. But it was identified that this error was resulted from insufficient test environment (temperature error between solenoid and sensing coils was about 2% at high temperature condition). Therefore, solenoid type position indicator shows that it is very suitable in reactor vessel as a high precision rod position indicator.

Indirect Kalman Filter based Sensor Fusion for Error Compensation of Low-Cost Inertial Sensors and Its Application to Attitude and Position Determination of Small Flying robot (저가 관성센서의 오차보상을 위한 간접형 칼만필터 기반 센서융합과 소형 비행로봇의 자세 및 위치결정)

  • Park, Mun-Soo;Hong, Suk-Kyo
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.7
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    • pp.637-648
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    • 2007
  • This paper presents a sensor fusion method based on indirect Kalman filter(IKF) for error compensation of low-cost inertial sensors and its application to the determination of attitude and position of small flying robots. First, the analysis of the measurement error characteristics to zero input is performed, focusing on the bias due to the temperature variation, to derive a simple nonlinear bias model of low-cost inertial sensors. Moreover, from the experimental results that the coefficients of this bias model possess non-deterministic (stochastic) uncertainties, the bias of low-cost inertial sensors is characterized as consisting of both deterministic and stochastic bias terms. Then, IKF is derived to improve long term stability dominated by the stochastic bias error, fusing low-cost inertial sensor measurements compensated by the deterministic bias model with non-inertial sensor measurement. In addition, in case of using intermittent non-inertial sensor measurements due to the unreliable data link, the upper and lower bounds of the state estimation error covariance matrix of discrete-time IKF are analyzed by solving stochastic algebraic Riccati equation and it is shown that they are dependant on the throughput of the data link and sampling period. To evaluate the performance of proposed method, experimental results of IKF for the attitude determination of a small flying robot are presented in comparison with that of extended Kaman filter which compensates only deterministic bias error model.

Robust Designs to Outliers for Response Surface Experiments

  • Jeong B. Yoo;Park, Sung H.
    • Journal of the Korean Statistical Society
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    • v.20 no.2
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    • pp.147-155
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    • 1991
  • This paper treats a robust design criterion which minimizes the effects of outliers and model inadequacy, and investigates robust designs for some response surface designs. In order to develop a robust design criterion and robust design, the integrated mean squared error of *(equation omitted) over a region is utilized, where *(equation omitted). is the estimated response by the minimum bias estimation proposed by carson, Manson and Hader (1969) . According to the number of aberrant observations and their positions, the proposed criterion and designs are studied. Also further development of the proposed criterion is treated when outliers can occur in any position of a design.

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