• ETRI Journal
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• 제27권5호
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• pp.563-568
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• 2005

A motion-control chip contains major functions that are necessary to control the position of each motor, such as generating velocity command profiles, reading motor positions, producing control signals, driving several types of servo amplifiers, and interfacing host processors. Existing motion-control chips can only generate velocity profiles of fixed characteristics, typically linear and s-shape smooth symmetric curves. But velocity profiles of these two characteristics are not optimal for all tasks in industrial robots and automation systems. Velocity profiles of other characteristics are preferred for some tasks. This paper proposes a motion-control chip to generate velocity profiles of desired acceleration and deceleration characteristics. The proposed motion-control chip is implemented with a field-programmable gate array by using the Very High-Speed Integrated Circuit Hardware Description Language and Handel-C. Experiments using velocity profiles of four different characteristics will be performed.

• 로봇학회논문지
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• 제14권2호
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• pp.104-113
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• 2019

Object manipulation in cluttered environments remains an open hard problem. In cluttered environments, grasping objects often fails for various reasons. This paper proposes a novel task and motion planning scheme to grasp objects obstructed by other objects in cluttered environments. Task and motion planning (TAMP) aims to generate a sequence of task-level actions where its feasibility is verified in the motion space. The proposed scheme contains an open-loop consisting of three distinct phases: 1) Generation of a task-level skeleton plan with pose references, 2) Instantiation of pose references by motion-level search, and 3) Re-planning task based on the updated state description. By conducting experiments with simulated robots, we show the high efficiency of our scheme.

• 방송공학회논문지
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• 제9권1호
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• pp.54-63
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• 2004

서로 다른 프레임 율을 가진 영상매체 사이의 프레임 호환을 위해, 움직임 추정 (motion estimation, ME)과 움직임 보상을 이용한 중간 영상 삽입 (합성) 기법 (motion compensated interpolation, MCI)이 활용되는데, 본 논문에서는 MCI에 적합한 움직임 추정기법을 제안하고, 제안한 움직임 추정 기법을 종래의 MCI에 적용한다. 종래의 방법에선 움직임 추정 블록과 MCI 블록의 크기가 동일하나, 본 논문에서 사용된 움직임 추정 블록은 MCI 블록과 같은 중심 축을 가지고, MCI 블록보다 더 크기 때문에 인접 블록과 중첩된 특성을 가진다. 제안한 움직임 추정 블록에 의한 계산량 증가를 줄이기 위해, 제안한 움직임 추정 블록내의 화소를 샘플링 하여 움직임 추정을 실행하였다. 제안한 방식을 검증하기 위해, 움직임 추정 블록을 다양한 샘플 계수로 샘플링 한 후 움직임 추정을 실행하였다. 제안한 방식으로 추정된 움직임 벡터 (motion vector, MV)를 활용하여 MCI를 수행하였으며, 수행된 결과를 종래의 방식에 의한 결과와 비교하였다.

• 대한전자공학회논문지SP
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• 제44권2호
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• pp.74-81
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• 2007

이 논문에서는 H.264의 효율적인 움직임 추정을 위한 새로운 SAD(Sum of Absolute Differences) 프로세서의 구조를 제안하였다. SAD 프로세서는 전영역 탐색기법의 움직임 추정이나 고속 탐색기법의 움직임 추정에서 모두 사용되는 중요한 블록이다. 제안된 구조는 SAD 계산기 블록, combinator 블록, 최소값 계산기 블록의 3개의 블록으로 구성된다. 제안된 구조는 덧셈연산을 분산 연산(Distributed Arithmetic)을 사용하여 계산함으로써 구조를 단순화시켰다. 제안 구조를 HDL(Hardware Description Language)을 사용하여 실험한 결과 기존의 구조와 비교하여 39%의 게이트 카운트 감소효과를 보였다. 또한 FPGA를 사용하여 검증한 결과도 32%의 게이트 카운트 감소효과를 보였다. 따라서 제안된 움직임 추정용 SAD 프로세서는 칩의 면적이 중요한 변수인 H.264 칩에서 널리 사용될 수 있는 구조가 될 것이다.

• 한국해양공학회지
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• 제20권4호
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• pp.70-75
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• 2006

A numerical procedure is described for estimating the effects of the multi-directional irregular waves on the motion responses and tension variations of the ISSC-TLP. The numerical approach is based on a three-dimensional source distribution method and a spectral analysis technique of directional waves. The spectral description for the linear system of ISSC-TLP in the frequency domain is sufficient to completely define the motion responses and tension variations. This is because both the wave inputs and responses are stationary Gaussian random processes, of which the statistical properties in the amplitude domain are well known. The numerical results for the linear motion responses and tension variations in regular waves are compared with the experimental and numerical ones, which are obtained in the literature. The results of comparison confirmed the validity of the proposed approach.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.263-264
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• 2007

In this paper, an efficient SAD(Sum of Absolute Differences) processor structure for motion estimation of 0.264 is proposed. SAD processors are commonly used both in full search methods for motion estimation or in fast search methods for motion estimation. Proposed structure consists of SAD calculator block, combinator block, and minimum value calculator block. Especially, proposed structure is simplified by using Distributed Arithmetic for addition operation. The Verilog-HDL(Hard Description Language) coding and FPGA implementation results for the proposed structure show 39% and 32% gate count reduction comparison with those of the conventional structure, respectively. Due to its efficient processing scheme, the proposed SAD processor structure can be widely used in size dominant H.264 chip.

• Journal of Magnetics
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• 제12권3호
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• pp.113-117
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• 2007

Here we report a theoretical description of ferromagnetic vortex dynamics. Based on Thiele's formulation of the Landau-Lifshitz-Gilbert equation, the motion of the vortex core could be described by a function of the vortex core position. Under a parabolic potential generated in the circular magnetic patterns, the vortex core showed a circular rotation-namely the gyrotropic motion, which could be described by a 2-dimensional simple harmonic oscillator. The gyrotropic frequency and apparent damping constant were predicted and compared with the values obtained micromagnetic calculation.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.71-77
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• 2010

As a hybrid model of continuum motion description which combines the advantages of classical kinematical descriptions i.e. Lagrangian and Eulerian description, the ALE (Arbitrary Lagrangian Eulerian) description is adopted for the simulation of a fluid-structure interaction of solid propellant rocket interior. The fluid-structure interaction phenomenon with the deformation of solid domain during the simulation. The developed solver is applied flow and propellant structure. The computed results show complex flow physics in the combustion chamber and the behavior of a solid propellant deformation.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2016년도 추계학술발표대회
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• pp.677-680
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• 2016

In computer vision and image processing, feature detection and description are essential parts of many applications which require a representation for objects of interest. Applications like object recognition or motion tracking will not produce high accuracy results without good features. Due to its importance, research on image feature has attracted a significant attention and several techniques have been introduced. This paper provides a review on well-known image feature detection and description techniques. Moreover, two experiments are conducted for the purpose of evaluating the performance of mentioned techniques.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.539-544
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• 1991

In order to verify robot motions for a desired work, it is necessary to visualize it on a computer screen. This paper presents a simulation algorithm for robot manipulator motion. Kinematic description is based on the Denavit- Hartenberg link representation. In order to be applied to various types of the robot manipulator, inverse kinematics make use of the Newton-Raphson iterative method with the least squares method. Joint variables are interpolated by the lowest polynomial segment satisfying acceleration continuity. The robot motions are generated and then animated on a computer screen in the form of skeleton type.