• Title/Summary/Keyword: 관성 행렬

Search Result 46, Processing Time 0.02 seconds

A study on kinematics and dynamics of robot arms by simulation (로봇 팔의 운동해석에 관한 연구)

  • 조선휘;김영일;임태홍
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.10 no.5
    • /
    • pp.611-617
    • /
    • 1986
  • In this paper, it is attempted to derive the minimum torque as the optimal value on each joint, which is applied during a PTP-motion in the range of working area of a supposed industrial robot. The rupposed industrial robot consits of 3-R joints prepared on three links, The optimizational analysis is performed by the formulation of a variational calculus process due to Rayleigh-Ritz method. That is, the torques of the inverse dynamic problem on joints in a arbitrary positions are computed by a generalized inertia matrix method.

A Study on Calculation of Cross-Section Properties for Composite Rotor Blades Using Finite Element Method (유한요소법 기반의 복합재료 블레이드 단면 특성치 계산에 관한 연구)

  • Park, Il-Ju;Jung, Sung-Nam;Cho, Jin-Yeon;Kim, Do-Hyung
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.37 no.5
    • /
    • pp.442-449
    • /
    • 2009
  • A two-dimensional cross-section analysis program based on the finite element method has been developed for composite blades with solid, thin-walled and compound cross-sections. The weighted-modulus method is introduced to determine the laminated composite material properties. The shear center and the torsion constant for any given section are calculated according to the Trefftz' definition and the St. Venant torsion theory, respectively. The singular value problem of cross-section stiffness properties faced during the section analysis has been solved by performing an eigenvalue analysis to remove the rigid body mode. Numerical results showing the accuracy of the program obtained for stiffness, offset and inertia properties are compared in this analysis. The current analysis results are validated with those obtained by commercial software and published data available in the literature and a good correlation has generally been achieved through a series of validation study.

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
    • /
    • v.32 no.3
    • /
    • pp.159-163
    • /
    • 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.

An Implementation of Acoustic Echo Canceller Using Adaptive Filtering in Modulated Lapped Transform Domain (Modulated Lapped Transform 영역에서 적응 필터링을 이용한 음향 반향 제거기의 구현)

  • 백수진;박규식
    • The Journal of the Acoustical Society of Korea
    • /
    • v.22 no.6
    • /
    • pp.425-433
    • /
    • 2003
  • Acoustic Echo Canceller (AEC) is a signal processing system for removing unwanted echo signals in teleconference and hands-free communication. Least mean square (LMS) algorithm is one of the adaptive echo cancellation algorithms and it has been most attractive because of its simplicity and robustness. However, the convergence properties of the LMS algorithm degrade with highly correlated input signals such as speech. For this reason, transform-domain adaptive filtering algorithm was introduced to decorrelate the colored input samples by using the orthogonal transform matrix such as DCT, DFT and then LMS adaptive filtering process is applied. In this paper, we propose a MLT domain adaptive echo canceller base on the MLT (Modulated lapped Transform) orthogonal transform matrix. The proposed algorithm achieves high decorrelation efficiency and fast convergence speed via modulated lapped transform of size 2NXN instead of NXN unitary transform such as DCT, DFT, Hadamad and it is applied to the acoustical echo cancellation system. Form the computer simulation with both synthesis and real speech, the proposed MLT domain adaptive echo canceller shows approximately twice faster convergence speed and 20∼30 ㏈ ERLE improvements over the DCT frequency domain acoustic echo cancellation system.

Enhancement on 3 DoF Image Stitching Using Inertia Sensor Data (관성 센서 데이터를 활용한 3 DoF 이미지 스티칭 향상)

  • Kim, Minwoo;Kim, Sang-Kyun
    • Journal of Broadcast Engineering
    • /
    • v.22 no.1
    • /
    • pp.51-61
    • /
    • 2017
  • This paper proposes a method to generate panoramic images by combining conventional feature extraction algorithms (e.g., SIFT, SURF, MPEG-7 CDVS) with sensed data from an inertia sensor to enhance the stitching results. The challenge of image stitching increases when the images are taken from two different mobile phones with no posture calibration. Using inertia sensor data obtained by the mobile phone, images with different yaw angles, pitch angles, roll angles are preprocessed and adjusted before performing stitching process. Performance of stitching (e.g., feature extraction time, inlier point numbers, stitching accuracy) between conventional feature extraction algorithms is reported along with the stitching performance with/without using the inertia sensor data.

Estimation of Vibration Level Inside an Engine Based on Rigid Body Theory and Measurement Technology (강체 운동 해석 및 실험을 통한 엔진 내부 진동 예측에 관한 연구)

  • Kim, Byung-Hyun;Park, Jong-Ho;Kim, Eui-Yeol;Lee, Sang-Kwon;Kim, Tae-Jeong;Heo, Jeong-Ki
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.21 no.11
    • /
    • pp.1043-1050
    • /
    • 2011
  • This paper presents practical results for the estimation of vibration level inside a powertrain based on the rigid body theory and measurement. The vibration level of inside powertrain has been used for the calculation of excitation force of an engine indirectly. However it was difficult to estimate or measure the vibration level inside of a powertrain when a powertrain works on the driving condition of a vehicle. To do this work, the rigid body theory is employed. At the first, the vibration on the surface of a powertrain is measured and its results are secondly used for the estimation the vibration level inside of powertrain together with rigid body theory. Also did research on how to decrease the error rate when the rigid body theory is applied. This method is successfully applied to the estimation of the vibration level on arbitrary point of powertrain on the driving condition at the road.

Inertial Sensor Aided Motion Deblurring for Strapdown Image Seekers (관성센서를 이용한 스트랩다운 탐색기 훼손영상 복원기법)

  • Kim, Ki-Seung;Ra, Sung-Woong
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.40 no.1
    • /
    • pp.43-48
    • /
    • 2012
  • This paper proposes a practical linear recursive robust motion deblurring filter using the inertial sensor measurements for strapdown image seekers. The angular rate information obtained from the gyro mounted on the missile is used to define the PSF(point spread function). Since the gyro output contains a unknown but bounded bias error. the motion blur image model can be expressed as the linear uncertain system. In consequence, the motion deblurring problem can be cast into the robust Kalman filtering which provides reliable state estimates even in the presence of the parametric uncertainty due to the gyro bias. Through the computer simulations using the actual IR scenes, it is verified that the proposed algorithm guarantees the robust motion deblurring performance.

Parametric Study on Dynamic Stability Behaviors of Beck's Column considering Shear Deformation and Damping Effects (전단변형 및 감쇠효과를 고려한 비보존력을 받는 외팔기둥의 동적 안정성거동에 대한 매개변수연구)

  • Lee, Jun-Seok;Kim, Nam-Il;Kim, Moon-Young
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.9 no.6 s.46
    • /
    • pp.1-12
    • /
    • 2005
  • For a shear-deformable beam-column element subjected io non-conservative forces, equations of motion and a finite element formulation are presented applying extended Hamilton's principle. The influence of non-conservative force's direction parameter, internal and external damping forces, and shear deformation and rotary inertia effects on divergence and flutter loads of Beck's columns are intensively investigated based on element stiffness, damping and mass matrixes derived for the non-conservative system.

Robust Transfer Alignment Method based on Krein Space (크레인 공간에 기반한 강인한 전달정렬 기법)

  • Sung-Hye Choe;Ki-Young Park;Hyoung-Min Kim;Cheol-Kwan Yang
    • Journal of Advanced Navigation Technology
    • /
    • v.25 no.6
    • /
    • pp.543-549
    • /
    • 2021
  • In this paper, a robust transfer alignment method is proposed for a strapdown inertial navigation system(SDINS) with norm-bounded parametric uncertainties. The uncertainties are described by the energy bound constraint, i.e., sum quadratic constraint(SQC). It is shown that the SQC can be coverted into an indefinite quadratic cost function in the Krein space. Krein space Kalman filter is designed by modifying the measurement matrix and the variance of measurement noises in the conventional Kalman filter. Since the proposed Krein space Kalman filter has the same recursive structure as a conventional Kalman filter, the proposed filter can easily be designed. The simulation results show that the proposed filter achieves robustness against measurement time delay and high dynamic environment of the vehicle.

Semi-analytical Annular Mindlin Plate Element for Out-of-plane Vibration Analysis of Thick Disks (두꺼운 디스크의 면외 진동 해석을 위한 준-해석적 환상 민드린 평판 요소)

  • Kim, Chang-Boo;Cho, Hyeon Seok;Beom, Hyeon Gyu
    • Journal of the Korean Society for Railway
    • /
    • v.15 no.6
    • /
    • pp.588-596
    • /
    • 2012
  • This paper presents a new semi-analytical annular Mindlin plate element with which out-of-plane natural vibration of thick disks can be analyzed simply, efficiently, and accurately through FEM by including effects of rotary inertia and transverse shear deformation. Using static deformation modes which are exact solutions of equilibrium equations of annular Mindlin plate, the element interpolation functions, stiffness and mass matrices corresponding to each number of nodal diameters are derived. The element is capable of representing out-of-plane rigid-body motions exactly and free from shear locking. Natural frequencies of uniform and multi-step disks with or without concentric ring support are analyzed by applying the presented element. Such results are compared with theoretical predictions of previous works or FEA results obtained by using two-dimensional shell element to investigate the convergence and accuracy of the presented element.