• Journal of Advanced Marine Engineering and Technology
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• 제40권2호
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• pp.120-130
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• 2016

In general, a series of ship steering motions is composed of a combination of translational motions and rotational motions of the ship. In particular, a series of rotational motions frequently occurs in narrow areas such as ports and canal zones. In this paper, a method was suggested for composing an integrated control algorithm based on the jog dial as a command instrument for rotational motion control. In order to realize the rotational motions, several algorithms were suggested for generating rotational commands, for selecting motion variables, for choosing reference input values for the motion variables, for computing required accelerations and thrusts, and for allocating thrusts to actuators. A simulation program was compiled to execute simulations for three rotational motions. Finally, the effectiveness of the suggested method was verified by analyzing the simulation results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.396-399
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• 2003

This paper proposes a simple digital image stabilization(DIS) algorithm for roll motion, which has not been compensated in the 2-axes mechanical stabilization system, using aero-crossing of the rotational motion vectors. The 2-axes stabilization system cannot stabilize rolled images, which causes the deteriorated performance of the object detection and recognition. In this paper, we propose the rotational motion stabilization algorithm which estimates and compensates global motion in terms of rotational center and rotational angle. Both the synthetic images with undesirable rotational disturbance and the real images from 2-axes stabilization system are used to evaluate the proposed algorithm. The results show that our proposed algorithm suppresses the undesirable rotational disturbance effectively.

• 한국정밀공학회지
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• 제25권4호
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• pp.140-147
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• 2008

This paper represents an ultra precision rotational device where the smooth impact drive mechanism (SIDM) is utilized as driving mechanism. Linear motions of piezoelectric elements are converted to the rotational motion of disk by frictional forces generated between the rotational disk and the friction part that is attached to the piezoelectric element. This device was designed to drive the rotational disk using slip-slip motion mechanism instead of stick-slip motion mechanism occurred in conventional impact drive mechanism. Experimental results show that the angular velocity is increased in proportion to the magnitude and frequency of supplied voltage to piezoelectric element and decreased as the preload is increased. In our device, the smooth rotational motion was obtained when the driving frequency has been reached to 500Hz under the driving voltage of 100V.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.714-718
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• 2009

3D reconstruction of a human face from an image sequence remains an important problem in computer vision. We propose a method, based on a factorization algorithm, that reconstructs a 3D face model from short image sequences exhibiting rotational motion. Factorization algorithms can recover structure and motion simultaneously from one image sequence, but they usually require that all feature points be well tracked. Under rotational motion, however, feature tracking often fails due to occlusion and frame out of features. Additionally, the paucity of images may make feature tracking more difficult or decrease reconstruction accuracy. The proposed 3D reconstruction approach can handle short image sequences exhibiting rotational motion wherein feature points are likely to be missing. We implement the proposal as a reconstruction method; it employs image sequence division and a feature tracking method that uses Active Appearance Models to avoid the failure of feature tracking. Experiments conducted on an image sequence of a human face demonstrate the effectiveness of the proposed method.

• 반도체디스플레이기술학회지
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• 제6권1호
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• pp.37-41
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• 2007

Recently PZT is used in ultra precision mechanism field. PZT has a small motion range although it has a high resolution. Many methods, such as inchworm, impact driving, etc., have been applied for the expansion of the motion range.? In this study, the new actuating mechanism for rotational motion with two PZT actuators is proposed. The ultra precision rotational actuator which is made by proposed mechanism is able to operate both coarse and fine motion. The design parameters of the proposed mechanism are considered to improve the performance of the system. The rotational stage which is applied by the proposed mechanism is fabricated. The resolution and velocity for fabricated rotational stage are measured by laser interferometer.

• 소음진동
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• 제5권4호
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• pp.483-492
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• 1995

For evaluation of rotational accuracy performance of high speed machine tool spindle system, the characteristics of main spindle and tool motion behavior are presented by means of three point accuracy testing method. The results of experiments and analyses are as follows: (1) The high speed spindle rotational accuracy can be evaluated by the combination of the spindle and tool motion behavior. (2) The spindle motion behavior increases up to more that 4 times the tool motion behavior. (3) For the influence of oil viscosity on spindle and tool taper application, 32 cSt of oil viscosity showed the most satisfactory result for rotational accuracy. (4) In order to improve the rotational accuracy of high speed machine tool spindle system, it is needed to reduce the combination error. This can be achieved by improving the working accuracy and supplying the proper lubrication with contact area at the spindle and tool.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.46-48
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• 2004

This paper presents a simple method of rotational and translational motion estimation for digital image stabilization. The scheme first computes the rotation center by taking least squares of selected local velocity vectors, and the rotational angle is found from special subset of motion vectors. And then translational motion can be estimated by the relation among movement of rotation center, rotation angle and translation movement. To show the effectiveness of our approach, the synthetic images are evaluated, resulting in better performance.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.485-486
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• 2006

This paper represents a ultra precision rotational device where the smooth impact drive mechanism(SIDM) is utilized as a driving mechanism. Linear motions of piezoelectric elements are converted to the rotational motion of disk by frictional forces generated between the rotational disk and the friction bars which are attached to the piezoelectric elements. This device was designed to drive a rotational disk using slip-slip motion mechanism based on stick-slip motion mechanism. Experimental results show that the angular velocity was increased in proportion to the magnitude of supplied voltage to piezoelectric element. In our device, the smooth rotational motion was obtained when the driving frequency has been reached to 500Hz under the driving voltage of 100V. The amount of step movement has been revealed to be $3.44{\times}10^{-4}$ radian.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.231-236
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• 2003

This paper presents a simple approach on the rotational motion estimation and correction for the roll stabilization of the sight system. The algorithm first computes the rotational center from the selected local velocity vectors of related pixels by least square methods. And then, rotational angle is found from the special subset of the motion vector. Finally, motion correction is performed by the nearest neighbor interpolation technique. In order to show the performance of the algorithm, the evaluation for the synthetic and real image was performed. The test results show good performance compared with previous approach.

• 한국전자통신학회논문지
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• 제19권2호
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• pp.445-452
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• 2024

본 논문에서는 회전형 관성항법장치의 핵심 기술인 최적 회전 절차를 설계하기 위하여 회전 동작별 항법 오차를 분석하는 내용을 다룬다. 회전형 관성항법장치는 관성측정기를 주기적으로 회전시킴으로써 관성센서 오차가 유발하는 항법 오차가 자체적으로 상쇄되도록 고안되었다. 적절히 연이어진 회전 동작은 최대한의 항법 오차를 상쇄시키며, 이를 최적 회전 절차라고 한다. 본 논문에서는 이러한 최적 회전 절차를 설계하기 위하여 회전형 관성항법장치에서 구현 가능한 회전 동작을 구분하고, 각 회전 동작 시 발생되는 항법 오차에 대해 분석한다. 또한 이를 조합하여 회전 절차를 수행할 때 발생되는 항법 오차의 특성을 분석함으로써 최적 회전 절차를 구성하기 위한 조건을 제시한다.