• Title, Summary, Keyword: measure of observability

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Singular Value Decomposition Approach to Observability Analysis of GPS/INS

  • Hong, Sin-Pyo;Chun, Ho-Hwan
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.133-138
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    • 2006
  • Singular value decomposition (SDV) approach is applied to the observability analysis of GPS/INS in this paper. A measure of observability for a subspace is introduced. It indicates the minimum size of perturbation in the information matrix that makes the subspace unobservable. It is shown that the measure has direct connections with observability of systems, error covariance, and singular structure of the information matrix. The observability measure given in this paper is applicable to the multi-input/multi-output time-varying systems. An example on the observability analysis of GPS/INS is given. The measure of observability is confirmed to be less sensitive to system model perturbation. It is also shown that the estimation error for the vertical component of gyro bias can be considered unobservable for small initial error covariance for a constant velocity horizontal motion.

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Measures of modal and gross controllability/observability for linear time-varying systems (선형 시변 시스템에 대한 모드 및 총가제어성/가관측성 척도)

  • Choe, Jae-Won;Lee, Ho-Chul;Lee, Dal-Ho
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.6
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    • pp.647-655
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    • 1999
  • For linear time-varying systems described by the triple (A(t),B(t),C(t)) where A(t),B(t),C(t) are the system, the input, and the output matrices, respectively, we propose concepts for measures of modal and gross controllability /observability. We introduce a differential algebraic eigenbvalue theory for linear time-varying systems to calculate the PD-eigenvalues and left and right PD-eigenvectors of the system matrix A(t) which will be used to derive the concepts for the measures. The time-dependent angle between the left PD-eigenvectors of the system matrix A(t) and the columns of the input matrix B(t), and the magnitude of the each element of the input matrix B(t) are used to propose the modal controllability measure. Similarly, the time-dependent angle between the right PD-eigenvectors of the system matrix A(t) and the rows of the output matrix C(t) are used to propose the madal observability measure. Gross measure of controllability of a mode from all inputs and its gross measure of observability in all outputs for the linear time-varying systems are also proposed. Numerical examples are presented to illustrate the proposed concepts.

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A Study on Observability of Model Parameters for Robot Calibration (로봇 캘리브레이션을 위한 모델 파라미터의 관측성 연구)

  • 범진환;양수상;임생기
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.4
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    • pp.64-71
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    • 1997
  • Objective of calibration is to find out the accurate kinematic relationships between robot joint angles and the position of the end-effector by estimating accurate model parameters defining the kinematic function. Estimating the model parameters requires measurement of the end-effector position at a number of different robot configurations. This paper studies the implication of measurement configurations in robot calibration. For selecting appropriate measurement configurations in robot calibration, an index is defined to measure the observability of the model parameters with respect to a set of robot configurations. It is found that, as the observability index of the selected measurement configurations increase the attribution of the position errors to the parameter errors becomes dominant while the effects of the measurement and unmodeled errors are less significant; consequently better estimation of parameter errors is expected. To demonstrate the implication of the observability measure in robot calibration, computer simulations are performed and their results are discussed.

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The Observability Analysis of SDINS on The Trajectory for The In-Flight Alignments (스트랩다운 관성항법 시스템의 운항 중 정렬을 위한 궤적에 따른 가관측성 분석)

  • Park, Joon-Goo;Lee, Jang-Gyu;Park, Chan-Gook;Chung, Do-Hyung
    • Proceedings of the KIEE Conference
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    • pp.1002-1004
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    • 1996
  • In this paper, presented are the results of observability analysis for the vehicle maneuver during In-Flight Alignment of SDINS. The target system for observability analysis is 10th order one. Three trajectories for IFA are considered. To analyze the observability of the time varying system, correlation coefficient is used and to measure the degree of observability of the given system, simulation is carried out using covariance matrix. The results of simulation show that trajectories which are having continuous changes in attitude and acceleration of system is superior to straight trajectory in correcting navigation errors.

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Monte-Carlo Simulation and measuring for Error Analysis of 3-axis SCARA Robot using Observability (관측성을 이용한 3축 SCARA Robot의 오차분석을 위한 Monte-Carlo simulation 및 측정)

  • Ju, Ji-Hun;Chung, Won-Jee;Kim, Jung-Hyun
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.4
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    • pp.8-14
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    • 2008
  • This paper aims at finding out dominant robot configurations with maximal position errors, which can be attributed to the parameter errors, by using Monte-Carlo simulation for error analysis of a 3-axis SCARA(Selective Compliance Assembly Robot Arm) type robot. In particular, the Monte-Carlo simulation is used for virtually measuring on the position errors, instead of physical measurement. In order to measure the observability of the model parameters with respect to a set of robot configurations, we propose the observability index which is defined as the product of singular values for error propagation matrices. Thus the index can be used for discriminating dominant robot configurations from a set of simulated ones in conjunction with standard deviation of positional errors, This paper analyzed error by robot positional error.

Study on the Observability of a Calibration System for a Parallel Tilting Table with Measuerment Operator (측정연산자에 의한 병렬기구 틸팅 테이블의 관측성에 관한 연구)

  • Park Kun Woo;Lee Min Ki;Kim Tae Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.6
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    • pp.795-803
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    • 2005
  • This paper studies the observability of calibration system with a measurement operator. The calibration system needs a simple digital indicator to measure the mobile table movements with respect to the MC coordinate. However, it yields the concern about the poor parameter observability due to measuring only a part of the movements. We uses the QR-decomposition to find the optimal calibration configurations maximizing the linear independence of rows of an observation matrix. The number of identifiable parameter is examined by the rank of the observation matrix, which represents the parameter observability. The method is applied to a 6-axis MC with parallel tilting table and the calibration results are presented. These results verify that all necessary kinematic parameters are observable and the calibration system has robustness to the noise using optimal calibration configurations.

Study on Calibration for Parallel-Typed Tilting Table (병렬기구형 틸팅 테이블의 보정에 관한 연구)

  • Kim, T.S.;Jung, J.W.;Kim, Y.H.;Park, K.W.;Lee, M.K.
    • Proceedings of the KSME Conference
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    • pp.1512-1517
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    • 2003
  • This paper presents the calibration for the parallel typed tilting table. The calibration system needs only simple sensing device which is a digital indicator to measure the orientation of a table. The calibration algorithm is developed by a measurement operator. It eliminates the concern about the poor parameter observability due to a large number of parameters of parallel-mechanism. This paper uses the QR-decomposition to find the optimal calibration configurations maximizing the linear independence of rows of a observation matrix. The number of identifiable parameters is examined by the rank of the observation matrix, which represents the parameter observability. The method is applied to a Parallel-typed Tilting Table and all the necessary kinematic parameters are identifiable.

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Adaptive intermittent maneuvers for intercept performance improvement of homing missile with passive seeker (수동형 탐색기를 장착한 호우밍 미사일의 요격성능 향상을 위한 적응 단속 기동)

  • Tark, Min-Jea;Ryu, Hyeok
    • 제어로봇시스템학회:학술대회논문집
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    • pp.469-474
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    • 1990
  • The implementation of modern guidance law derived from optimal control theory requires accurate current states of target, for example, position, velocity and acceleration etc. But there is no sensors that measure the target states directly. So they are estimated from measurable data. For atmospheric missile engagement, direct application of the modern guidance laws may result In deterioration of Intercept performance because of poor observability associated with angles only-measurements by passive seeker and homing geometry. In this paper, a trajectory modulation method called "adaptive Intermittent maneuvers" is added to the modern guidance law, so the observability is enhanced and, consequently, improved the intercept performance. The estimation algorithm called "modified gain pseudo-measurement filter" is used for tracking filter. It is assumed that the passive seeker measure the angles between line of sight and Inertial frame. The Monte-Carlo simulation for realistic air-to-air Intercept scenario are conducted to demonstrate the effectiveness of intermittent maneuvers.ermittent maneuvers.

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Robust Observer Design for Multi-Output Systems Using Eigenstructure Assignment (고유구조 지정을 이용한 다중출력 시스템의 강인한 관측기 설계)

  • Huh, Kun-Soo;Nam, Joon-Chul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.11
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    • pp.1621-1628
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    • 2004
  • This paper proposes a design methodology for the robust observer using the eigenstructure assignment in multi-output systems so that the observer is less sensitive to the ill-conditioning factors such as unknown initial estimation error, modeling error and measurement bias in transient and steady-state observer performance. The robustness of the observer can be achieved by selecting the desired eigenvector matrix to have a small condition number that guarantees the small upper bound of the estimation error. So the left singular vectors of the unitary matrix spanned by space of the achievable eigenvectors are selected as a desired eigenvectors. Also, this paper proposes how to select the desired eigenvector based on the measure of observability and designs the observer with small gain. An example of a spindle drive system is simulated to validate the robustness to the ill-conditioning factors in the observer performance.

Decoupled Control of Active and Permanent Magnetic Bearing System (자기 베어링과 영구자석 베어링으로 이루어진 시스템의 비 연성 제어)

  • Park, Sang-Hyun;Lee, Chong-Won
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.63-70
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    • 2008
  • In this paper, we propose a bearing redundant coordinates and decoupled PD controller for 5-axes active magnetic bearing system, which consists of two bearing parts such as three-pole hybrid active magnetic bearing for stabilize the radial direction and ring-type permanent magnetic bearing stabilizing in axial and tilting motion. Based on derived system equation with decoupled control scheme, we conduct the modal analysis and measure of modal controllability and observability.

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