• 제목/요약/키워드: Direct algorithm

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Predictive Direct Torque Control Algorithm for Induction Motors and its Digital Implementation

  • Mutschler, Peter;Flach, Erich
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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    • pp.1-6
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    • 1998
  • To achieve fast control action, direct control methods should be used. "Direct Mean Torque Control" (DMTC) combines the good dynamic performance of Direct Torque Control (DTC) with the advantages of inherently constant switching frequency and time equidistant control for implementation in a digital signal processor. Since DMTC is a predictive control algorithm, the model and its correction deserves special investigations. This paper proposes a steady-state Kalman filter which is well suited for fast computation.mputation.

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비동기 양상태 소나 시스템을 위한 직접파 탐지 기법 (Direct blast detection algorithm for asynchronous bistatic sonar systems)

  • 정의철;안재균;김주호
    • 한국음향학회지
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    • 제37권3호
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    • pp.139-146
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    • 2018
  • 단상태 소나는 음원의 송신시간과 반사파의 수신시간 정보를 이용하여 표적의 위치를 산출한다. 그러나 음원의 송신시간 정보를 수신센서와 공유하지 않는 비동기 양상태 소나 시스템에서는 표적의 위치를 산출하기 위해 수신센서에서 음원의 직접파(direct blast)를 탐지해야한다. 본 논문에서는 직접파에 대한 PRI(Pulse Repetition Interval)와 적응적인 임계치 추정을 통해 직접파 탐지를 수행하는 기법을 제안한다. 모의 신호 및 해상 실험 데이터를 이용하여 제안하는 기법의 성능을 분석하였고 그 결과 강한 배경소음 및 직접파와 유사한 다수의 표적 반사파가 존재하는 환경에서도 강인한 직접파 탐지 성능을 보여주었다.

홍익 직접 구동팔의 동적 제어기 개발 (Design and implementation of a dynamic controller for Hong-Ik Direct Drive Arm)

  • 이재완;이종수;최경삼
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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    • pp.1052-1057
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    • 1993
  • A scara type Direct Drive Arm(DDA) with two degrees-of-freedom is designed and implemented. The direct drive motor is used to furnish large torque to reduce the modeling error by the gear and chains. To control the DDA, a multiprocessor control structure with multirate dynamic control algorithm is designed. In the control algorithm, the dynamics of system is used to calculate the nominal control torque and the feedback controls are calculated with a parallel processing algorithm for each joint. The laboratory experiments on Hong-Ik DDA by dynamic control algorithm are presented and compared to that of PID control algorithm. This result shows that the proposed controller guarantees small trajectory error and stability. With this research, Hong-Ik DDA is expected to be utilized as A basic tool for robotics and control engineering.

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완전해싱을 위한 DHP 연관 규칙 탐사 알고리즘의 개선 방안 (Improvement of DHP Association Rules Algorithm for Perfect Hashing)

  • 이형봉
    • 한국정보과학회논문지:데이타베이스
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    • 제31권2호
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    • pp.91-98
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    • 2004
  • DHP 연관 규칙 탐사 알고리즘은 후보 빈발 항목 집합들에 대한 계수를 유지하기 위한 해쉬트리의 크기를 가능한 한 줄이기 위하여, 독립된 직접 해쉬 테이블을 미리 준비해 놓았다가 후보 빈발 항목 집합을 생성할 때 적용함으로써 전지 효과를 얻는다. 이 때 직접 해쉬 테이블의 크기가 클수록 전지효과는 커지며, 특히 길이 2인 후보 빈발 항목 집합을 생성하는 단계에서의 전지 효과는 알고리즘 전체의 성능을 좌우할 만큼 큰 영향을 발휘한다. 따라서 급속도로 보편화되고 있는 대용량 주기억장치 시스템 추세에 따라 단계 2에서의 직접 해쉬 테이블 크기의 극단적인 증가에 대한 시도가 이루어지고 있으며, 이러한 것 중의 하나가 완전 해쉬 테이블이다. 그러나 단계 2에서의 완전 해쉬 테이블을 사용할 경우, 이를 단순히 기존 DHP 알고리즘에 적용하여 버켓 크기(|H$_2$|)만을 재 설정하는 것 보다, DHP 알고리즘 자체를 조금 변경했을 때 약 20% 이상의 추가 성능 이득을 얻을 수 있음이 밝혀졌다. 이 논문에서는 단계 2에서의 완전 해쉬 테이블의 타당성을 조명해 본 후, 그 특성을 충분히 활용하도록 DHP를 개선한 PHP 알고리즘을 제안하며 그 결과를 실험적 환경에서 검증한다.

3상회로 직접해석에 의한 배편계통 1선지락사고 고장거리 계산 알고리즘 (A New fault Location Algorithm for a Line to Ground fault Using Direct 3-phase Circuit Analysis in Distribution Power Networks)

  • 최면송;이승재;이덕수;진보건;민병운
    • 대한전기학회논문지:전력기술부문A
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    • 제51권8호
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    • pp.409-416
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    • 2002
  • This paper presents a fault location algorithm using direct 3-phase circuit analysis for distribution power networks. The unbalanced feature of distribution networks due to single phase loads or asymmetric operation prohibits us from using the conventional symmetrical component transformation. Even though the symmetrical component transformation provides us with a very easy tool in three phase network analysis, it is limited to balanced systems in utilizing its strong point, which is not suitable for distribution networks. In this paper, a fault location algorithm using direct 3-phase circuit analysis is developed. The algorithm is derived and it Is shown that the proposed method if we use matrix inverse lemma, is not more difficult then the conventional methods using symmetrical component transformation. Since the symmetrical component transformation is not used in the suggested method, unbalanced networks also can be handled with the same difficulty as balanced networks. The case study results show the correctness and effectiveness of the proposed algorithm.

A 2D-FFT algorithm on mesh connected multiprocessor systems

  • Kunieda, Hiroaki;Itoh, Kazuhito
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집(한일합동학술편); 한국과학기술대학, 충남; 16-17 Oct. 1987
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    • pp.851-856
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    • 1987
  • A direct computation algorithm of two dimensional fast Fourier transform (2D-FFT) is considered here for implementation in mesh connected multiprocessor array of both a 2D-toroidal and a rectangular type. Results are derived for a hardware algorithm including data allocation and interprocessor communications. A performance comparison is carried out between the proposed direct 2D-FFT computation and the conventional one to show that a new algorithm gives higher speedup under a reasonable assumption on the speeds of operations.

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B-spline 곡선을 power 기저형태의 구간별 다항식으로 바꾸는 Direct Expansion 알고리듬 (A Direct Expansion Algorithm for Transforming B-spline Curve into a Piecewise Polynomial Curve in a Power Form.)

  • 김덕수;류중현;이현찬;신하용;장태범
    • 한국CDE학회논문집
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    • 제5권3호
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    • pp.276-284
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    • 2000
  • Usual practice of the transformation of a B-spline curve into a set of piecewise polynomial curves in a power form is done by either a knot refinement followed by basis conversions or applying a Taylor expansion on the B-spline curve for each knot span. Presented in this paper is a new algorithm, called a direct expansion algorithm, for the problem. The algorithm first locates the coefficients of all the linear terms that make up the basis functions in a knot span, and then the algorithm directly obtains the power form representation of basis functions by expanding the summation of products of appropriate linear terms. Then, a polynomial segment of a knot span can be easily obtained by the summation of products of the basis functions within the knot span with corresponding control points. Repeating this operation for each knot span, all of the polynomials of the B-spline curve can be transformed into a power form. The algorithm has been applied to both static and dynamic curves. It turns out that the proposed algorithm outperforms the existing algorithms for the conversion for both types of curves. Especially, the proposed algorithm shows significantly fast performance for the dynamic curves.

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지역적 특성과 부하특성을 고려한 직접부하제어 알고리즘 (Direct Load Control Algorithm Based Locational and Electric Load Characteristics)

  • 신호성;송경빈;문종필;김재철;남봉우
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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    • pp.264-265
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    • 2006
  • This paper presents direct load control algorithm based locational and electric load characteristics. Direct load control is defined that demand-side management program activities that can interrupt consumer load at the time of annual peak load by direct control of the utility system operator by interruption power supply to individual appliances or equipment on consumer premises. Korean power system is divided into 14-areas considering branches operating in KEPCO, and electric loads are classified into 19 load groups considering interruption costs in this paper. The purpose of proposed method is to decrease social losses by controlling electric loads mainly whose interruption costs are low. It is expected that the proposed algorithm can be used as the countermeasure for the emergency state of the electric power dispatch in a operation point of view.

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신경회로망을 이용한 직접 구동형 로봇의 위치제어에 관한 연구 (A Study on Position Control of the Direct Drive Robot Using Neural Networks)

  • 신춘식;황용연;노창주
    • Journal of Advanced Marine Engineering and Technology
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    • 제21권3호
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    • pp.284-292
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    • 1997
  • This paper is concerned with position control of direct drive robots. The proposed algorithm consists of the feedback controller and neural networks. Mter the completion of learning, the output of the feedback controller is nearly equal to zero, and the neural networks play an important role in the control system. Therefore, the optimum retuning of control parameters is unnecessary. In other words, the proposed algorithm does not need any knowledge of the con¬trolled system in advance. The effectiveness of the proposed algorithm is demonstrated by the experiment on the position control of a parallelogram link-type direct drive robot.

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Sensorless Starting of Direct Drive Horizontal Axis Washing Machines

  • Dianov, Anton;Kim, Nam Su;Lim, Seung Moo
    • Journal of international Conference on Electrical Machines and Systems
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    • 제3권2호
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    • pp.148-154
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    • 2014
  • This paper describes problems of the sensorless starting of horizontal axis washing machines with direct drive and suggests solution, which was experimentally verified. Horizontal axis washing machines have very difficult conditions for the drive starting, especially at full load. Inertia of the tub and water, torque from the laundry make load torque at starting higher than rated one and sometimes even higher than the maximum torque of the motor, which makes sensorless starting extremely challenging task. This paper suggests modified open-loop starting, where control system is closed shortly after beginning at low speed and rotates the drum until laundry restructuring. To ensure proper work of the sensorless algorithm at low speed additional measures for increasing of the estimation algorithm performance have been taken. These measures include special algorithm for the drive parameters estimation, which has been developed and verified by the experimental results.