• Title/Summary/Keyword: inverse method

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A Study on the Inverse Kinematics for a Biped Robot (2족 보행 로봇의 역기구학에 관한 연구)

  • 성영휘
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.12
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    • pp.1026-1032
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    • 2003
  • A biped walking robot which is developed as a platform for researching walking algorithm is briefly introduced. The developed walking robot has 6 degrees of freedom per one leg. The origins of the last three axis do not intersect at a point, so the kinematic analysis is cubmersome with the conventional method. In the former version of the robot, Jacobian-based inverse kinematics method is used. However, the Jacobian-based inverse kinematics method has drawbacks for the application in which knee is fully extended such as stair-case walking. The reason far that is the Jacobian becomes ill-conditioned near the singular points and the method is not able to give adequate solutions. So, a method for giving a closed-form inverse kinematics solution is proposed. The proposed method is based on careful consideration of the kinematic structure of the biped walking robot.

A Study on the Automatic Fairing and Modeling System of Hull From (선형의 자동순정 및 모델링 시스템에 관한 연구)

  • 김동준
    • Journal of Ocean Engineering and Technology
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    • v.14 no.2
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    • pp.121-127
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    • 2000
  • In this paper a new technique of inverse fairing problem for ship hull is proposed. Recently Lu solved the inverse fairing problem for automobile's body that was made by one surface element. In this system however hull surface is constructed by Gregory's composite surface interpolation method. So reflection line at boundary position is used as a tool of solving inverse problem in surface fairing. But the results are not good. The new concepts of Normal vector line and Constrained reflection line are introduced as an alternative tool. Energy minimization method for Normal Vector Line curve net and the inverse method for Constrained Reflection Line by using optimization technique are examined And the final lines from this proposed surface fairing method shows good fairness.

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Inverse dynamic analysis of flexible robot arms with multiple joints (다관절 유연 로보트 팔의 역동력학 해석)

  • 김창부;이승훈
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10a
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    • pp.254-259
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    • 1992
  • In this paper, we propose an optimal method for the tracking a trajectory of the end-effector of flexible robot arms with multiple joints. The proposed method finds joint trajectories and joint torques necessary to produce the desired end-effector motion of flexible manipulator. In inverse kinematics, optimized joint trajectories are computed from elastic equations. In inverse dynamics, joint torques are obtained from the joint equations by using the optimized joint trajectories. The equations of motion using finite element method and virtual work principle are employed. Optimal control is applied to optimize joint trajectories which are computed in inverse kinematics. The simulation of flexible planner manipulator is presented.

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A Study on the Viscous Inverse Method for the High Speed Axisymmetric Body Design (고속 축대칭 비행체 설계를 위한 점성 Inverse 기법 연구)

  • Lee Young-Ki;Lee Jaewoo
    • Journal of computational fluids engineering
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    • v.2 no.2
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    • pp.35-43
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    • 1997
  • An efficient inverse method for 1.he supersonic/hypersonic axisymmetric body design is developed for the parabolized Navier-Stokes equations. The developed method is examined numerically for three extreme testcases in the supersonic(M/sub ∞/=3.0) and hypersonic(M/sub ∞/=6.28) speeds. The first one is a negative pressure distribution near a vacuum pressure and the second one is a positive pressure distribution over the whole region of the body. The last one is the case of abrupt change of pressure distribution to zero in the forward region of the body. These testcases show the robustness of the method. By introducing a regular-falsi method and by using a not-fully converged inverse solution, the convergence behavior was greatly improved.

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A Study on Constructing Inverse Element Generator over $GF(3^{m})$

  • Park Chun Myoung;Song Hong Bok
    • Proceedings of the IEEK Conference
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    • 2004.08c
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    • pp.514-518
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    • 2004
  • This paper presents an algorithm generating inverse element over finite fields $GF(3^{m})$, and constructing method of inverse element generator based on inverse element generating algorithm. A method computing inverse of an element over $GF(3^{m})$ which corresponds to a polynomial over $GF(3^{m})$ with order less than equal to m-l. Here, the computation is based on multiplication, square and cube method derived from the mathematics properties over finite fields.

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SVD Pseudo-inverse and Application to Image Reconstruction from Projections (SVD Pseudo-inverse를 이용한 영상 재구성)

  • 심영석;김성필
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.17 no.3
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    • pp.20-25
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    • 1980
  • A singular value decomposition (SVD) pseudo-inversion method has been applied to the image reconstruction from projections. This approach is relatively unknown and differs from conventionally used reconstructioll methods such as the Foxier convolution and iterative techniques. In this paper, two SVD pseudo-inversion methods have been discussed for the search of optimum reconstruction and restoration, one using truncated inverse filtering, the other scalar Wiener filtering. These methods partly overcome the ill-conditioned nature of restoration problems by trading off between noise and signal quality. To test the SVD pseudo-inversion method, simulations were performed from projection data obtained from a phantom using truncated inversefiltering. The results are presented together with some limitations particular to the applications of the method to the general class of 3-D image reconstruction and restoration.

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Three Dimensional Multi-step Inverse Analysis for Optimum Blank Design in Sheet Metal Forming (박판금속성형의 최적 블랭크 설계를 위한 삼차원 다단계 역해석)

  • Lee, Choong-Ho;Huh, Hoon
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.03a
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    • pp.179-182
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    • 1997
  • One-step inverse methods based on deformation theory causes some amount of error. The amount of error is generally increased as the deformation path is more complex. As a remedy, a new three dimensional multi-step inverse method is introduced for optimum design of blank shapes and strain distributions from desired final shapes. The approach extends a one-step inverse method to a multi-step inverse method in order to reduce the amount of error. The algorithm developed is applied to square cup drawing to confirm its validity by demonstrating reasonably accurate numerical results.

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A Study on the Inverse Element Generation Algorithm over $GF(3^m)$ (유한체 $GF(3^m)$상에서 역원생성 알고리즘에 관한 연구)

  • Park, Chun-Myoung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2008.10a
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    • pp.768-771
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    • 2008
  • This paper presents an algorithm for generating inverse element over finite fields $GF(3^m)$, and constructing method of inverse element generator based on inverse element generating algorithm. The method need to compute inverse of an element eve. $GF(3^m)$ which corresponds to a polynomial eve. $GF(3^m)$ with order less than equal to m-1. Here, the computation is based on multiplication, square and cube method derived from the mathematics properties over finite fields.

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A Study on the Improvement of Convergence for a Discrete-time Learning Controller by Approximated Inverse Model (근사 역모델에 의한 이산시간 학습제어기의 수렴성 개선에 관한 연구)

  • Moon, Myung-Soo;Yang, Hai-Won
    • Proceedings of the KIEE Conference
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    • 1989.07a
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    • pp.101-105
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    • 1989
  • The iterative learning controller makes the system output follow the desired output over a finite time interval through iterating trials. In this paper, first we discuss that the design problem of learning controller is originally the design problem of the inverse model. Then we show that the tracking error which is the difference between the desired output and the system output is reduced monotonically by properly modeled inverse system if the magnitude of the learning operator being introduced is bounded within the unit circle in complex domain. Also it would be shown that the conventional learning control method is a kind of extremely simplified inverse model learning control method of the objective controlled system. Hence this control method can be considered as a generalization of the conventional learning control method. The more a designer model the objective controlled system precisely, the better the performance of the approximated inverse model learning controller would be. Finally we compare the performance of the conventional learning control method with that of the approximated inverse model learning control method by computer simulation.

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Inverse Problem Methodology for Parameter Identification of a Separately Excited DC Motor

  • Hadef, Mounir;Mekideche, Mohamed Rachid
    • Journal of Electrical Engineering and Technology
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    • v.4 no.3
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    • pp.365-369
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    • 2009
  • Identification is considered to be among the main applications of inverse theory and its objective for a given physical system is to use data which is easily observable, to infer some of the geometric parameters which are not directly observable. In this paper, a parameter identification method using inverse problem methodology is proposed. The minimisation of the objective function with respect to the desired vector of design parameters is the most important procedure in solving the inverse problem. The conjugate gradient method is used to determine the unknown parameters, and Tikhonov's regularization method is then used to replace the original ill-posed problem with a well-posed problem. The simulation and experimental results are presented and compared.