• Title/Summary/Keyword: Coordinates transformation

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A Study on the Real-Time Analysis of a 6×6 Autonomous Vehicle (6×6 자율주행 차량의 실시간 해석을 위한 연구)

  • Cho, Du-Ho;Lee, Jung-Han;Yi, Ki-Chang;Yoo, Wan-Suk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.12
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    • pp.1433-1441
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    • 2009
  • In multibody dynamic analysis, one of the most important problems is to reduce computation times for real-time simulation. This paper presents the derivation procedure of equations of motion of a 6${\times}$6 autonomous vehicle in terms of chassis local coordinates which do not require coordinates transformation matrix to enhance efficiency for real-time dynamic analysis. Also, equations of motion are derived using the VT(velocity transformation) technique and symbolic computation method coded by MATLAB. The Jacobian matrix of the equations of motion of a system is derived from symbolic operations to apply the implicit integration method. The analysis results were compared with ADAMS results to verify the accuracy and approve the feasibility of real time analysis.

Inverse Dynamic Analysis of Flexible Multibody Systems with Closed-Loops

  • Lee, Byung-Hoon;Lee, Shi-Bok;Jeong, Weui-Bong;Yoo, Wan-Suk;Yang, Jin-Saeng
    • Journal of Mechanical Science and Technology
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    • v.15 no.6
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    • pp.693-698
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    • 2001
  • The analysis of actuating forces (or torques) and joint reaction forces (or moments) are essential to determine the capacity of actuators, to control the system and to design the components. This paper presents an inverse dynamic analysis algorithm for flexible multibody systems with closed-loops in the relative joint coordinate space. The joint reaction forces are analyzed in Cartesian coordinate space using the inverse velocity transformation technique. The joint coordinates and the deformation modal coordinates are used as the generalized coordinates of a flexible multibody system. The algorithm is verified through the analysis of a slider-crank mechanism.

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Determination of Absolute Coordinates of Permanent GPS Site (GPS 상시관측소의 절대좌표 산정에 관한 연구)

  • 윤홍식;황진상
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.19 no.4
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    • pp.415-423
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    • 2001
  • This paper deals with the data processing method relative to reference frames through the calculation of absolute coordinates of permanent GPS site which was established at Sungkyunkwan University. In this paper. we computed the ITRF97 coordinates with high precision (0.0001 ppm) from GPS data analysis. Also, we derived the accurate coordinates referred to WGS84 and Korean Geodetic Datum (KGD) using transformation parameters provided. ITRF97 coordinates were computed by using the GIPSY-OASIS II (GOA II) software and the algorithms for determining the position developed Jet Propulsion Laboratory (JPL). The coordinates referred to WGS84 and KGD were derived from the transformation parameters provided by International Earth Rotation Service (IERS) and National Geography Institute (NGI). The parameters determined by NGI were calculated from the 2000 project of the establishment of geocentric coordinate system. We tested its availability through the comparison of the coordinates obtained from local GPS data analysis.

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The Realization of the Three Dimensional Guidance Law Using Modified Augmented Proportional Navigation (개선된 부가비례항법을 이용한 3차원 유도법칙의 구현)

  • Kim, Y.M.;Seo, J.H.
    • Proceedings of the KIEE Conference
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    • 1995.11a
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    • pp.222-224
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    • 1995
  • This paper deals with 3-dimensional missile guidance law. This presents the general optimal solution of the state equation which includes the target maneuvering as the Gauss-Markov processing. The main results ore about the transformation between the Cartesian coordinates on which both the guidance law and the filter are bused and the polar coordinates system in real missile guidance and measurement information. And the extended Kalman filter and adjustment of the estimated target acceleration by triangular functions is proposed solution to this transformation problem. It is shown that this proposed transformation is valid in real 3-dimensional guidance problem by the computer simulation.

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The effects of the geoidal height determination in geodetic origin on coordinates transformation between ellipsoids (Geoid 기준설정이 타원체간 좌표변환에 미치는 영향)

  • 강준묵;박운용;이용창
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.12 no.1
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    • pp.69-76
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    • 1994
  • In this paper, the characteristics of coordinate transformation between the WGS84 and the Bessel ellipsoids according to the assumed values of the geoidal height on Bessel ellipsoid at the geodetic datum origin of Korea were investigated. For this, based on GPS data of 11 control points in Chungnam and Chungbuk province, the mean shift values between ellipsoids were calculated in each case. The geoidal heights on the Bessel ellipsoid were modelled in the area and the coordinate transformation coefficients were derived, and then the accuracy of the transformed coordinates according to fluctuations in geoidal heights were studied.

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The Numerical Modelling and Dynamic Collapse Analysis of the Rectangular Tube (사각관의 수치 모델링 및 동적 붕괴 해석)

  • 강신유;한동철
    • Transactions of the Korean Society of Automotive Engineers
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    • v.1 no.2
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    • pp.42-48
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    • 1993
  • In this paper, dynamic collapse behavior of the rectangular tube under impact loading is anlayzed using nonlinear finite element method of shell element. In case of shell element formulation using corotational element coordinates system, dynamic collapse behavior is analyzed without initial imperfection, and with initial imperfection. This paper reveals that the collapse of a rectangular tue without initial imperfection is caused by an error of transformation of the corotational coordinates system.

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National Datum Transformation Parameters of South Korea Using Weighted Parameter Constraints (가중변수법에 의한 국가좌표계 변환요소의 산정)

  • 이영진
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.15 no.1
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    • pp.29-39
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    • 1997
  • The need of transformation parameters from local geodetic datums to a geocentric coordinate system is becoming more common, with the increasing application of satellite positioning techniques to LIS/GIS survey with cadastral management. In this paper, the national transformation parameters between the Korean geodetic coordinates which is based on the Bessel 1841 ellipsoid and the WGS84 ellipsoid are determined by the least square methods with weighted parameter constraints. Three-dimensional geocentric coordinates are based on GPS observation at 31 stations in the geodetic network, the datum parameters are computed within a standard deviation of less than 1 meter. In South Korea, the national transformation parameters with Bessel geoid-heights are useful for GPS baseline processing and for middle-scale map/database transformation.

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A compliant control method for cooperating two arms with asymetric kinematic structures (비대칭 구조를 갖는 두 협조 로봇의 컴플라이언스 제어방법)

  • 여희주;서일홍
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.7
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    • pp.40-50
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    • 1996
  • An unified compliant control algorithm to regulate the force by dual arms is proposed, where tow arms are treated as one arm in a kinematic viewpoint. The force error calculated form the information of two force/torque sensors attached to the end of each arm is transferred to minimum actuator coordinates, and then is distributed to total system actuator coordinates. The position adjustment at the total actuator coordinates is computed based on the effective computed based on the effective compliance matrix with respect to total actuator coordinates, which is obtained by coordinate transformation between the task coordinates and the total actuator coordinates. An experiment is carried out for dual arms with asymmetric kinematic structure to control an interaction force between manipulators and the environment. The performances of the proposed control algorithm are experimentally compared to those of dual arms employing master/slave scheme. The proposed compliant control algorithm not only ouperforms other algorithms, but also can be treated as an unified approach n the sense that it can be applied to arbitrary dual arm systems with general kinematic structures.

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Measurement and Algorithm Calculation of Maxillary Positioning Change by Use of an Optoelectronic Tracking System Marker in Orthognathic Surgery (악교정수술에서 광전자 포인트 마커를 이용한 상악골 위치 변화의 계측 및 계산 방법 연구)

  • Park, Jong-Woong;Kim, Soung-Min;Eo, Mi-Young;Park, Jung-Min;Myoung, Hoon;Lee, Jong-Ho;Kim, Myung-Jin
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.33 no.3
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    • pp.233-240
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    • 2011
  • Purpose: To apply a computer assisted navigation system to orthognathic surgery, a simple and efficient measuring algorithm calculation based on affine transformation was designed. A method of improving accuracy and reducing errors in orthognathic surgery by use of an optical tracking camera was studied. Methods: A total of 5 points on one surgical splint were measured and tracked by the Polaris $Vicra^{(R)}$ (Northern Digital Inc Co., Ontario, Canada) optical tracking system in two cases. The first case was to apply the transformation matrix at pre- and postoperative situations, and the second case was to apply an affine transformation only after the postoperative situation. In each situation, the predictive measuring value was changed to the final measuring value via an affine transformation algorithm and the expected coordinates calculated from the model were compared with those of the patient in the operation room. Results: The mean measuring error was $1.027{\pm}0.587$ using the affine transformation at pre- and postoperative situations and the average value after the postoperative situation was $0.928{\pm}0.549$. The farther a coordinate region was from the reference coordinates which constitutes the transform matrixes, the bigger the measuring error was found which was calculated from an affine transformation algorithm. Conclusion: Most difference errors were brought from mainly measuring process and lack of reproducibility, the affine transformation algorithm formula from postoperative measuring values by using of optic tracking system between those of model surgery and those of patient surgery can be selected as minimizing the difference error. To reduce coordinate calculation errors, minimum transformation matrices must be used and reference points which determine an affine transformation must be close to the area where coordinates are measured and calculated, as well as the reference points need to be scattered.

Development of Mandibular Movements Measuring System Using Double Stereo-Cameras

  • Park, Soon-Yong;Park, Sung-Kee;Cho, Chang-Hyun;Kim, Mun-Sang;Park, Mi-Gnon
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.1183-1188
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    • 2005
  • In this paper, we propose a 3D automated measuring system which measures the mandibular movements and the reference plane of the jaw movements. In diagnosis and treatment of the malocclusions, it is necessary to estimate the mandibular movements and the reference plane of the jaw movements. The proposed system is configured with double stereo-cameras, PC, two moving pattern plates(MPPs), two fixed pattern plates(FPPs) and one orbital marker. The virtual pattern plate is applied to calculate the homogeneous transformation matrices which describe the coordinates systems of the FPP and MPP with respect to the world coordinates system. To estimate the parameters of the hinge axis, the Euler's theorem is applied. The hinge axis points are intersections between the FPPs and the hinge axis. The coordinates of a hinge axis point with respect to the MPP coordinates system are set up to fixed value. And then, the paths of the jaw movement can be calculated by applying the homogeneous transformation matrix to fixed hinge axis point. To examine the accuracy of the measurements, experiments of measuring the hinge axis points and floating paths of them are performed using the jaw motion simulator. As results, the measurement errors of the hinge axis points are within reasonable boundary, and the floating paths are very similar to the simulator's moving path.

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