• 제목/요약/키워드: Reaching Time

검색결과 694건 처리시간 0.021초

Finite-Time Nonlinear Disturbance Observer Based Discretized Integral Sliding Mode Control for PMSM Drives

  • Zheng, Changming;Zhang, Jiasheng
    • Journal of Power Electronics
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    • 제18권4호
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    • pp.1075-1085
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    • 2018
  • To deal with the operation performance degradation of permanent magnet synchronous machine (PMSM) drives with uncertainties and unmodeled dynamics, this paper presents a finite-time nonlinear disturbance observer (FTNDO) based discretized integral sliding mode (DISM) composite control scheme. Based on the reaching-law approach, a DISM speed controller featuring a superior dynamic quality and global robustness against disturbances is constructed. This controller can avoid the reaching phase and overlarge control action. In addition, a sliding mode differentiator based FTNDO is devised and extended to the discrete-time domain for disturbance estimation. The attractive features of the FTNDO are that it can provide a finite-time converging estimation and alleviate the chattering effect in conventional sliding mode observers, while retaining robustness to parameter variations. By feeding the estimate forward to the pre-stage DISM controller, both disturbances and chattering can be significantly suppressed. Moreover, considering the estimation error of a FTNDO caused by discrete sampling, a stability analysis of the composite controller is discussed. Experimental results validate the superiority of the presented scheme.

상동광산 광미를 활용한 자기충전 콘크리트의 품질 특성에 관한 연구 (An Experimental Study on the Quality Properties of Self-Compacting Concrete Containing Tailings in Sangdong Mine)

  • 최연왕;정문영;정명채;김용직;구기정
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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    • pp.437-440
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    • 2003
  • This study has focused on the possibility for recycling of tailings from the Sangdong tungsten mine as powder of self-compacting concrete(SCC). The experimental tests for slump-flow, reaching time to the slump-flow of 500mm, V-funnel and U-box were carried out in accordance with the specified by the Japanese Society of Civil Engineering(JSCE). The result of this study, in case of SCC mixed with tailings, slump-flow was decreased with increasing mixing ratio. But reaching time slump-flow of 500mm, V-funnel and U-box were satisfied a prescribed range. The mechanical properties including compressive strength, splitting tensile strength and static modulus of elasticity were checked with the requirements specified by Korean Industrial Standard(KS). The compressive strength of SCC was decreased with increasing replacement, splitting tensile strength and static modulus were similar to those of normal concrete.

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현장 불평형 응답을 이용한 로터-베어링 시스템의 매개변수 규명연구 (A Study on Identifying Dynamic Characteristic Parameters of Rotor Bearing Systems Using Field Measurement Data of Unbalance Responses)

  • 이동환;김영일;박노길
    • 연구논문집
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    • 통권29호
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    • pp.101-109
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    • 1999
  • Presented in this paper is a new method of identifying the critical speed of rotor-bearing systems without actually reaching at the critical speed itself. Using the method, it is not only possible to calculate the critical speed by measuring a series of rotor responses at much lower rotating speeds away from and without reaching at the critical speeds but also the damping ratio and eccentricity of the system can be identified at the same time. Two types of test rotors were tested on the Rotor Dynamics Test Facility at the Rotordyn-amics Lab, KIMM, and the theory has been confirmed experimentally. The method can be adopted to monitor changes of the dynamic characteristics of critical rotating machinery before and after overhauls, repairs, exchanges of various parts, or to detect trends of direction of subtle changes in the dynamic characteristic parameters over a long periods of time.

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로봇 매니퓰레이터의 추적 제어를 위한 퍼지 적응 슬라이딩 모드 제어기 (A Fuzzy Adaptive Sliding Mode Controller for Tracking Control of Robotic Manipulators)

  • 이진용;강희준
    • 제어로봇시스템학회논문지
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    • 제18권6호
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    • pp.555-561
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    • 2012
  • This paper describes the design of a fuzzy adaptive sliding mode controller for tracking control of robotic manipulators. The proposed controller incorporates a modified traditional sliding mode controller to drive the system state to a sliding surface and then keep the system state on this surface, and a fuzzy logic controller to accelerate the reaching phase. The stability of the control system is ensured by using Lyapunov theory. To verify the effectiveness of the proposed controller, computer simulation is conducted for a five-bar planar robotic manipulator. The simulation results show that the proposed controller can improve the reaching time and eliminate chattering of the control system at the same time.

냉방조건에서 실내기 위치 및 환기량에 따른 열쾌적성 및 유동 특성 (Thermal Comfort and Air Flow Patterns for Indoor Unit Positions and Ventilation Rates in Cooling Operation)

  • 고재윤;강태욱;박률
    • 설비공학논문집
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    • 제20권4호
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    • pp.221-229
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    • 2008
  • This study analyze indoor thermal comfort properties such as PMV, PPD and fluid variables when the cooling loads are light, occupant and ventilation. There are 6 cases to study for the indoor unit installation conditions and ventilation rates. Numerical method is used to study the indoor environmental properties and experimental study is adapted to analyze reaching time by variable cooling load conditions.

로봇 매니퓰레이터를 위한 퍼지 이동슬라이딩 모드 제어 (Fuzzy Moving Sliding Model Control for Robotic Manipulators)

  • 전경한;최봉일
    • 제어로봇시스템학회논문지
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    • 제7권7호
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    • pp.597-604
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    • 2001
  • Recently, the study of the moving sliding mode in the variable structure control is in progress ac-tively. The conventional time-invariant sliding model control can\`t guarantee the sliding mode in the reaching phase, which is robust against the uncertainty. But with the time-varying method, the controller makes the states track the desired trajectories and keeps the sliding mode. Nevertheless, the piecewise continuous method of the past still has the reaching mode. Thus we propose the continuously moving sliding surface by the fuzzy algorithm. The proposed algorithm is made of the fuzzy rule considering both the error and the error velocity, and may apply to the entire phase plane without sacrificing sliding mode. Especially the proposed scheme can rotate tot he slope-decreasing direction, needless to say rotating to the slope-increasing direction. For showing that the proposed controller guarantees the sliding model and ensures the robustness, we apply the proposed method to the two-link robot manipulator simulation.

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Cure Characteristics, Mechanical Property and Ozone Resistance of Natural Rubber/Bromo Isobutylene Isoprene Rubber Blend

  • Choi, Im Cheol;Lee, Won-Ki;Park, Chan Young
    • Elastomers and Composites
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    • 제53권3호
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    • pp.168-174
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    • 2018
  • Natural rubber (NR) and bromo-isobutylene-isoprene rubber (BIIR) were compounded with other formulation chemicals through polymer blending via a mechanical mixing method. After rubber vulcanization by hot-press compression molding, the cure characteristics, mechanical properties, and ozone resistance of the NR/BIIR blends were measured. As the BIIR content increased, the maximum torque of the blends decreased, while the optimum cure time and scorch time tended to increase. Furthermore, the hardness of the blends increased with increasing BIIR content, reaching the maximum value at 75 wt% BIIR, and decreased with a further increase in the BIIR loading. The tensile strength and elongation at break decreased with an increase in the BIIR content, reaching the minimum value at 75 wt% BIIR, and increased with a further increase in the BIIR content. In the ozone resistance test, cracks were not generated when the BIIR content was more than 75 wt%.

가변구조 제어시스템에 있어서 위상면상에의 도달시간 감소 (Reduction of Reaching Time on Phase Plane in Variable Structure Control System)

  • 이주장;황동환
    • 대한전기학회논문지
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    • 제39권1호
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    • pp.51-59
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    • 1990
  • 이 논문에서 평면상에 도달하는 시간을 감소하는 새로운 가변구조제어 알고리즘이 제안되었다. 새로운 방법은 Morgan과 Ozguner의 알고리즘(스윗칭 변수의 미분치를 상수로 하는 항)에다가 스윗칭 변수의 크기에 비례하는 항을 첨가 하였다. 2차 시스템에 적용시킨 시뮬레이션 결과 Morgan의 알고리즘보다 이 새로운 접근 방법의 제어 알고리즘이 더욱 유효함을 보였다.

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현장 불평형 응답을 이용한 로터-베어링 시스템의 매개변수 규명 연구 (A Study on Identifying Dynamic Characteristic Parameters of Rotor Bearing Systems Using Field Measurement Data of Unbalance Responses)

  • 이동환;김영일;박노길
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 추계학술대회논문집
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    • pp.605-611
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    • 2000
  • Presented in this paper is a new method of identifying the critical speed of rotor-bearing systems without actually reaching at the critical speed itself. Using the method, it is not only possible to calculate the critical speed by measuring a series of rotor responses at much lower rotating speeds away from and without reaching at the critical speeds but also the damping ratio and eccentricity of the system can be identified at the same time. Two types of test rotors were tested on the Rotor Dynamics Test Facility at the Rotordynamics Lab., KIMM, and the theory has been confirmed experimentally. The method can be adopted to monitor changes of the dynamic characteristics of critical rotating machinery before and after overhauls, repairs, exchanges of various parts, or to detect trends of direction of subtle changes in the dynamic characteristic parameters over a long periods of time.

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니켈기 초내열 합금의 천이액상확산접합 특성에 미치는 접합 온도 및 가열 속도의 영향 (Effect of Bonding Temperature and Heating Rate on Transient Liquid Phase Diffusion Bonding of Ni-Base Superalloy)

  • 최우혁;김성욱;김종현;김길영;이창희
    • Journal of Welding and Joining
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    • 제23권2호
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    • pp.52-58
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    • 2005
  • This study was carried out to investigate the effect of bonding temperature and heating rate on transient liquid phase diffusion bonding of Ni-base superalloy. The heating rate was varied by $0.1^{\circ}C$/sec, $1^{\circ}C$/sec, $10^{\circ}C$/sec to the bonding temperatures $1100^{\circ}C,\;1150^{\circ}C,\;1200^{\circ}C$ under vacuum. As bonding temperature increased, maximum dissolution width of base metal increased, but a dissolution finishing time decreased. The eutectic width of insert metal in the bonded interlayer decreased linearly in proportion to the square root of holding time during isothermal solidification stage. The bonding temperature was raised, isothermal solidification rate slightly increased. As the heating rate decreased and the bonding temperature increased, the completion time of dissolution after reaching bonding temperature decreased. When the heating rate was very slow, the solidification proceeded before reaching bonding temperature and the time required for the completion of isothermal solidification became reduced.