• Title/Summary/Keyword: Velocity transformation method

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A Study on the Prediction & Transformation of Blasting Vibration for Environmental Regulation Standard (발파진동의 예측기법과 환경규제 기준으로의 변환 연구)

  • 김남수;양형식
    • Tunnel and Underground Space
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    • v.11 no.1
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    • pp.14-19
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    • 2001
  • The estimation of proper prediction method and the transformation method of environmental regulation standard were carried out by measuring blasting vibration. Vibration velocity was more adequate than vibration level in the blasting design by scaled distance. Thus, design and construction mutt be controlled by vibration velocity, and it is required that the vibration velocity is transformed to vibration level to meet regulation standard. Three transformation methods were studied. First, transformation formula is derived from the shock vibration data only. The second method it the transformation by correlation equation of vibration velocity and vibration level measured at the same time. The last one is the transformation of vibration velocity by FFT. It seems to be difficult to estimate damages by these methods because that every method shows considerable error. But transformation formula of PPV component to vibration level was most practical.

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An Efficient Multibody Dynamic Algorithm Using Independent Coordinates Set and Modified Velocity Transformation Method (수정된 속도변환기법과 독립좌표를 사용한 효율적인 다물체 동역학 알고리즘)

  • Kang, Sheen-Gil;Yoon, Yong-San
    • Proceedings of the KSME Conference
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    • 2001.06b
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    • pp.488-494
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    • 2001
  • Many literatures, so far, have concentrated on approaches employing dependent coordinates set resulting in computational burden of constraint forces, which is needless in many cases. Some researchers developed methods to remove or calculate it efficiently. But systematic generation of the motion equation using independent coordinates set by Kane's equation is possible for any closed loop system. Independent velocity transformation method builds the smallest size of motion equation, but needs practically more complicated code implementation. In this study, dependent velocity matrix is systematically transformed into independent one using dependent-independent transformation matrix of each body group, and then motion equation free of constraint force is constructed. This method is compared with the other approach by counting the number of multiplications for car model with 15 d.o.f..

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Inverse Dynamic Analysis of Mechanical Systems Using the Velocity Transformation Technique (속도변환기법을 이용한 기계시스템의 역동학적 해석)

  • Lee, Byeong-Hun;Yang, Jin-Saeng;Jeon, U-Seong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.12
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    • pp.3741-3747
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    • 1996
  • This paper presents a method for the inverse dynamic anlaysis of mechanical systems. Actuating forces(or torques) depending on the driving constraints are analyzed in the relative coordinate space using the velocity transformation technique. A systematic method to compose the inverse velocity transformation matrix, which is used to determine the joint reaction forces, is proposed. Two examples are taken to verify the method developed here.

Application of the nonlinear transformation and linear state state feedback control to nonlinear hydraulic servo system (비선형 유압 서보시스템의 비선형 변환 및 이에 대한 선형제어에 관한 연구)

  • 김영준;장효환
    • 제어로봇시스템학회:학술대회논문집
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    • 1989.10a
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    • pp.272-275
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    • 1989
  • In this paper feedback linearization of valve-controlled nonlinear hydraulic velocity control system is studied. The $C^{\infty}$ nonlinear transformation T is obtained, and it is shown that this transformation is global one. Linear equivalence of nonlinear hydraulic velocity control system is obtained by this global nonlinear transformation, and linear state feedback control law is applied to this linear model. It is shown that this transformation method is to the linear approximation by simulation study..

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Generalized Kinematics Modeling of Wheeled Mobile Robots (바퀴형 이동로봇의 기구학)

  • Shin, Dong-Hun;Park, Kyung-Hoon
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.5
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    • pp.118-125
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    • 2002
  • The previous kinematic analysis of wheeled mobile robots(WMRs) is performed in an ad-hoc manner, while those of the robot manipulators are done in a consistent way using the coordinate system assignment and the homogeneous transformation matrix. This paper shows why the method for the robot manipulators cannot be used directly to the WMRs and proposes the method for the WMRs, which contains modeling the wheel with the Sheth-Uicker notation and the homogeneous transformation. The proposed method enable us to model the velocity kinematics of the WMRs in a consistent way. As an implementation of the proposed method, the Jacobian matrices were obtained for conventional steered wheel and non-steered wheel respectively and the forward and inverse velocity kinematic solutions were calculated fur a tricycle typed WMR. We hope that our proposed method comes to hold an equivalent roles for WMRs, as that of the manipulators does for the robot manipulators.

Enhancing the Reconstruction of Acoustic Source Field Using Wavelet Transformation

  • Ko Byeongsik;Lee Seung-Yop
    • Journal of Mechanical Science and Technology
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    • v.19 no.8
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    • pp.1611-1620
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    • 2005
  • This paper shows the use of wavelet transformation combined with inverse acoustics to reconstruct the surface velocity of a noise source. This approach uses the boundary element analysis based on the measured sound pressure at a set of field points, the Helmholtz integral equations and wavelet transformation for reconstructing the normal surface velocity field. The reconstructed field can be diverged due to the small measurement errors in the case of nearfield acoustic holography (NAH) using an inverse boundary element method. In order to avoid this instability in the inverse problem, the reconstruction process should include some form of regularization for enhancing the resolution of source images. The usual method of regularization has been the truncation of wave vectors associated with small singular values, although the order of an optimal truncation is difficult to determine. In this paper, a wavelet transformation is applied to reduce the computation time for inverse acoustics and to enhance the reconstructed vibration field. The computational speed-up is achieved, with solution time being reduced to $14.5\%$.

A Study on circular Arc Approach for Motion Analysis of Oscillating Roller Follower and Disk Cam Mechanisms (요동운동 롤러 종동절과 디스크 캠 기구의 운동해석을 위한 원호 접근법에 관한 연구)

  • 구병국;신중호;윤호업;장옥화
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.523-526
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    • 2000
  • This paper performs the motion analysis for a disk cam and a follower mechanism using a circular arc method, a coordinate transformation method and an instant velocity method in order to find a contact point between the cam and the follower. Based on the proposed method, the displacement and the velocity are calculated by using the geometric relationships of the cam mechanism. Also, the acceleration is determined on using the central difference method. As the results, this paper presents the original curve and the analyzed curve for the motion analysis of the disk cam for an example.

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A study on relative velocity approach for shape desing to cylindrical cam with rotating roller follower on faced-vertical axes (직교축상의 회전운동용 롤러 종동절을 수반하는 원통형 캠의 형상설계를 위한 상대속도법에 관한 연구)

  • 김성원;신중호;강동우;장세원
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.612-615
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    • 2000
  • Cam mechanism is one of the common devices used in many automatic machinery. Specially cylindrical cam generates three dimensional motions. Thus, the shape design procedures must have high accuracy. This paper proposes the shape design procedure for a cylindrical cam and follower mechanism using a relative velocity method. The relative velocity method and the coordinate transformation are used to find a contact point between the cam and the follower. Also, the full shape of the cylindrical cam can be generated by using the geometric relationships and the contact constraints. As a result, this paper presents an example for the shape design of the cylindrical cam in order to prove the accuracy of the design procedures.

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A Study on Shape Design Approach of Cylindrical Cam for Automatic Tool Changer Using Relative Velocity (상대속도를 이용한 자동공구교환장치용 원통 캠의 형상 설계에 관한 연구)

  • Kim, S.W.;Shin, J.H.;Kang, D.W.;Chang, S.W.
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.813-817
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    • 2000
  • Cam mechanism is one of the common devices used in many automatic machinery. Specially cylindrical cam generates three dimensional motions. Thus, the shape design procedure must have high accuracy. This paper proposes the shape design procedure for a cylindrical cam and follower mechanism using a relative velocity method. The relative velocity method and coordinate transformation are used to find a contact point between cam and follower. Also, the full shape of the cylindrical cam can be generated by using the geometric relationships and the contact constraints. As a result, this paper presents an example for the sape design of the cylindrical cam in order to prove the accuracy of the design procedures.

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A Systematic Formulation for Dynamics of Flexible Multibody Systems (탄성 다물체계의 체계적인 동역학적 해석)

  • 이병훈;유완석
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.10
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    • pp.2483-2490
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    • 1993
  • This paper presents a systematic formulation for the kinematic and dynamic analysis of flexible multibody systems. The system equations of motion are derived in terms of relative and elastic coordinates using velocity transformation technique. The position transformation equations that relate the relative and elastic coordinates to the Cartesian coordinates for the two contiguous flexible bodies are derived. The velocity transformation matrix is derived systematically corresponding to the type of kinematic joints connecting the bodies and system path matrix. This matrix is employed to represent the equations of motion in relative coordinate space. Two examples are taken to test the method developed here.