• Title/Summary/Keyword: Taylor's expansion

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A Study on the Acceleration and Deceleration Control of Free-Form Surfaces (자유곡면의 가감속 제어에 관한 연구)

  • Baek, Dae Kyun;Yang, Seung-Han
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.9
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    • pp.745-751
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    • 2016
  • This paper presents the acceleration and deceleration control of free-form surfaces. A rapid variation of acceleration (or Deceleration) drives the system into a machine shock, resulting in the inaccuracy of the path control of the NURBS curve. The pattern of acceleration control can be established using the curvature of the NURBS curve. The curvature can be easily calculated from the first and second derivative of the NURBS curve used in Taylor's expansion for NURBS interpolation. However, the derivatives are not used in the recursive method for NURBS interpolation. Hence, we attempted the difference-derivatives for calculating the NURBS curvature. Both, Taylor's expansion and the recursive method, are used jointly for controlling the acceleration in the same interpolation algorithm.

Time Discretization of Nonlinear System with Variable Time-delay Input Using Taylor Series Expansion (Taylor series를 이용한 시변 지연 입력을 갖는 비선형 시스템의 이산화)

  • Choi Hyung Jo;Park Ji Hyang;Lee Su Young;Chong Kil To
    • Journal of Institute of Control, Robotics and Systems
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    • v.11 no.1
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    • pp.1-8
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    • 2005
  • A new discretization algorithm for nonlinear systems with delayed input is proposed. The algorithm is represented by Taylor series expansion and ZOH assumption. This method is applied to the sampled-data representation of a nonlinear system with the time-delay input. Additionally, the delay in input is time varying and its amplitude is bounded. The maximum time-delay in input is assumed to be two sampling periods. The mathematical expressions of the discretization method are presented and the ability of the algorithm is tested for some of the examples. The computer simulation proves the proposed algorithm discretizes the nonlinear system with the variable time-delay input accurately.

A HIGHER ORDER ITERATIVE ALGORITHM FOR MULTIVARIATE OPTIMIZATION PROBLEM

  • Chakraborty, Suvra Kanti;Panda, Geetanjali
    • Journal of applied mathematics & informatics
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    • v.32 no.5_6
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    • pp.747-760
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    • 2014
  • In this paper a higher order iterative algorithm is developed for an unconstrained multivariate optimization problem. Taylor expansion of matrix valued function is used to prove the cubic order convergence of the proposed algorithm. The methodology is supported with numerical and graphical illustration.

Development of Visual Servo Control System for the Tracking and Grabbing of Moving Object (이동 물체 포착을 위한 비젼 서보 제어 시스템 개발)

  • Choi, G.J.;Cho, W.S.;Ahn, D.S.
    • Journal of Power System Engineering
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    • v.6 no.1
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    • pp.96-101
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    • 2002
  • In this paper, we address the problem of controlling an end-effector to track and grab a moving target using the visual servoing technique. A visual servo mechanism based on the image-based servoing principle, is proposed by using visual feedback to control an end-effector without calibrated robot and camera models. Firstly, we consider the control problem as a nonlinear least squares optimization and update the joint angles through the Taylor Series Expansion. And to track a moving target in real time, the Jacobian estimation scheme(Dynamic Broyden's Method) is used to estimate the combined robot and image Jacobian. Using this algorithm, we can drive the objective function value to a neighborhood of zero. To show the effectiveness of the proposed algorithm, simulation results for a six degree of freedom robot are presented.

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Discretization of Nonlinear Systems with Delayed Multi-Input VIa Taylor Series and Scaling and Squaring Technique

  • Yuanliang Zhang;Chong Kil To
    • Journal of Mechanical Science and Technology
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    • v.19 no.11
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    • pp.1975-1987
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    • 2005
  • An input time delay always exists in practical systems. Analysis of the delay phenomenon in a continuous-time domain is sophisticated. It is appropriate to obtain its corresponding discrete-time model for implementation via digital computers. In this paper a new scheme for the discretization of nonlinear systems using Taylor series expansion and the zero-order hold assumption is proposed. The mathematical structure of the new discretization method is analyzed. On the basis of this structure the sampled-data representation of nonlinear systems with time-delayed multi-input is presented. The delayed multi-input general equation has been derived. In particular, the effect of the time-discretization method on key properties of nonlinear control systems, such as equilibrium properties and asymptotic stability, is examined. Additionally, hybrid discretization schemes that result from a combination of the scaling and squaring technique (SST) with the Taylor series expansion are also proposed, especially under conditions of very low sampling rates. Practical issues associated with the selection of the method's parameters to meet CPU time and accuracy requirements, are examined as well. A performance of the proposed method is evaluated using a nonlinear system with time delay maneuvering an automobile.

Implementation of Efficient Exponential Function Approximation Algorithm Using Format Converter Based on Floating Point Operation in FPGA (부동소수점 기반의 포맷 컨버터를 이용한 효율적인 지수 함수 근사화 알고리즘의 FPGA 구현)

  • Kim, Jeong-Seob;Jung, Seul
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.11
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    • pp.1137-1143
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    • 2009
  • This paper presents the FPGA implementation of efficient algorithms for approximating exponential function based on floating point format data. The Taylor-Maclaurin expansion as a conventional approximation method becomes inefficient since high order expansion is required for the large number to satisfy the approximation error. A format converter is designed to convert fixed data format to floating data format, and then the real number is separated into two fields, an integer field and an exponent field to separately perform mathematic operations. A new assembly command is designed and added to previously developed command set to refer the math table. To test the proposed algorithm, assembly program has been developed. The program is downloaded into the Altera DSP KIT W/STRATIX II EP2S180N Board. Performances of the proposed method are compared with those of the Taylor-Maclaurin expansion.

A Study on the Analysis of Multi-let Spread Mooring Systems (다점지지 계류시스템의 정적해석에 대한 연구)

  • Sin, Hyeon-Gyeong;Kim, Deok-Su
    • Journal of Ocean Engineering and Technology
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    • v.9 no.2
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    • pp.53-60
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    • 1995
  • A multi-leg spread mooring system for floating offshore structures is important, but the multi-leg static analysis is complicated due to the nonlinear behavior of each line and the effect of current which affects each line differently. The pretensioned position of the multi-leg mooring system obtained from the static equilibrium condition changes into a different position due to external loads and current. In this paper, the new position and the static tension at each line are caculated. The relation between the initial static equilibrium position and the new position due to the external loads is expressed in terms of the Taylor's series expansion. The Runge-Kutta $4^{th}$ method is employed in analyzing the 3-dimensional static cable nonlinear equations.

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