• Title, Summary, Keyword: Radial force

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Radial Force Control of a Novel Hybrid Pole BLSRM

  • Wang, Hui-Jun;Lee, Dong-Hee;Ahn, Jin-Woo
    • Journal of Power Electronics
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    • v.9 no.6
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    • pp.845-853
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    • 2009
  • This paper presents a novel hybrid pole BLSRM (Bearingless Switched Reluctance Motor) and its radial force control scheme. The proposed hybrid pole BLSRM has separated radial force poles and rotating torque poles. According to the FEM analysis, the proposed BLSRM has an excellent linear characteristic of radial force and controllability that is independent from the torque current. The radial force can be produced by the radial force winding which is wound at the separated radial force poles. The rotating torque is produced by the excitation current of the torque windings which are wound at the torque pole. The proposed radial force control scheme is independent of the phase torque winding current. A simple PID controller and look-up table are used to maintain a constant rotor air-gap. The proposed BLSRM and its radial force control scheme are verified by FEM analysis and experimental tests.

The Static Equivalent Radial Load under the Moment and Radial Force for the Deep Groove Ball Bearings (모멘트 하중을 고려한 깊은 홈 볼 베어링의 정등가 하중에 관한 연구)

  • 이재선;한동철
    • Tribology and Lubricants
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    • v.14 no.3
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    • pp.94-99
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    • 1998
  • Generally not only the radial load but also the moment may be applied to the ball bearings for a shaft system. However it has been difficult to determine the static equivalent load because there is the radial static equivalent equation only for the axial and radial force on the bearings. In this paper, the same static equivalent radial load which makes the maximum contact force at the interface between the ball and groove as the applied radial force and moment generate is calculated under the condition that the radial force and the moment are applied to the bearings simultaneously. The relation between the static equivalent load and applied force is studied. Therefore the simple and effective equation for the static equivalent radial load of the radial load and moment is proposed for the deep groove ball bearings.

Control of Radial Force in Double Stator Type Bearingless Switched Reluctance Motor

  • Peng, Wei;Xu, Zhenyao;Lee, Dong-Hee;Ahn, Jin-Woo
    • Journal of Electrical Engineering and Technology
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    • v.8 no.4
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    • pp.766-772
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    • 2013
  • Modeling and control of radial force in the double stator type bearingless switched reluctance motor (BLSRM) is researched. The rotational torque is controlled independently from the radial force control. And the radial force is constant which is independent from the rotor position. In order to realize steady suspension, analytical models of torque and radial force for the proposed structure are derived. Meanwhile, in order to realize steady suspension, control scheme for proposed BLSRM is proposed. In the control method, the radial force can be controlled in arbitrary direction and magnitude by selecting some combinations of radial force windings. The validities of structure and control method are verified by the experimental results.

On-line Simulaneous Identification of Immersion Ratio and Cutting Force Ratio using Cutting Forces in Face Milling (정면밀링에서 절삭력을 이용한 절입비와 절산력비의 실시간 추정)

  • 김명곤
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.9 no.4
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    • pp.91-98
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    • 2000
  • In this paper , presented is a method of on-line estimation of the radial immersion ratio and cutting force ratio using cutting force. When a tooth finishes sweeping, sudden drop of cutting forces occurs. These force drops are equal to the cutting forces that act on a single tooth at the swept angle of cut and can be obtained from cutting force signals in feed and crossfeed directions. The ratio of cutting forces in feed and cross-feed directions acting on the single tooth at the swept angle of cut is a function of the swept angle of cut and the ratio of radial to tangential cutting force. In the research, it is found that the ratio of radial to tangential cutting force is not affected by cutting conditions and axial rake angle. Therefore, the ratio of radial to tangential cutting force determined by just one preliminary experiment can be used regardless of the cutting conditions. Using the measured cutting forces, the radial immersion ratio is estimated along with the cutting force ratio at that immersion angle. Various experiments show that the radial immersion ratio and instantaneous ratio of the radial to tangential direction cutting force can be estimated by the proposed method very well.

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On-line Estimation of Radial Immersion Ratio Using Cutting Force and Instantaneous Cutting Force Ratio in Face Milling (정면밀링 가공 중 절삭력과 순간 절삭력 성분비를 이용한 반경방향 절입비의 실시간 추정)

  • Kim, Myeong-Gon;Gwon, Won-Tae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.8
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    • pp.2123-2130
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    • 2000
  • Radial immersion ratio is an important factor to determine the threshold in face milling and should be estimated in process for automatic force regulation. In this paper, presented is a method of on-line estimation of the radial immersion ratio using cutting force. When a tooth finishes sweeping, sudden drop of cutting forces occurs. This force drop is equal to the cutting force that acts on a single tooth at the swept angle of cut and can be obtained from cutting force signal in feed and cross-feed direction. The ratio of cutting forces in feed and cross-feed directions acting on the single tooth at the swept angle of cut is a function of the swept angle of cut and the ratio of radial to tangential cutting force. In the research, it is found that the ratio of radial to tangential cutting force is not affected by cutting conditions and axial rake angle. Therefore, the ratio of radial to tangential cutting force determined by just one preliminary experiment can be used regardless of the cutting conditions. Using the measured cutting force and predetermined ratio, the radial immersion ratio is estimated. Various experiments show that the radial immersion ratio and instantaneous ratio of the radial to tangential direction cutting force can be estimated very well by the proposed method.

CALCULATION OF RADIAL FORCE IN CIRCULAR COILS USING dM/dr (dM/dr에 의한 원형코일의 Radial Force 계산)

  • Kim, Gi-Bung;Gwon, Byeong-Il
    • Proceedings of the KIEE Conference
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    • pp.95-97
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    • 1996
  • Circular coils are widely used in electromagnetic applications, and the force in a sets of coils consisting of more than two can be divided into three components. Among them, one component called radial force is acting on the radial axis, and it is exposed as stree or impact. Calculation of the radial force was used to be performed by introducing Ampear's law of force which is $F=J{\times}B$. However, many cases in analyzing a system, calculation method from the mutual inductance between the coils is oftenly employed to get the axial force and resulting dynamics. In this case, if the calculation of radial force from the mutual inductance is possible, flow of the calculation for the system analysis would be much more simpler.

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Estimation of Radial Immersion Ratio and Instantaneous Ratio between Cutting Force Components using Cutting Force in Face Milling (정면밀링에서 절삭력을 이용한 반경방향 절입비와 순간 절삭력 성분 사이의 비 추정)

  • 김명곤
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.239-244
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    • 1999
  • Radial immersion ratio is an important factor to determine the threshold in face milling and should be estimated in process for automatic force regulation. In this paper, presented is a method of on-line estimation of radial immersion ratio using cutting force. When a tooth finishes sweeping, sudden drop of cutting forces occurs. These force drops are equal to the cutting forces that act on a single tooth at the swept angle of cut and can be acquired from cutting force signals in feed and cross-feed directions. The ratio of cutting forces in feed and cross-feed directions acting on the single tooth at the swept angle of cut is a function of the swept angle of cut and the ratio of radial to tangential cutting force. In the research, it is found that the ratio of radial to tangential cutting force is not affected by cutting conditions and axial rake angle. Therefore, the ratio of radial to tangential cutting force determined by just one preliminary experiment can be used regardless of the cutting conditions. Using the measured cutting forces and predetermined ratio, the redial immersion ratio is estimated. various experiments show that the radial immersion ratio can be estimated by the proposed method very well.

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On-line Estimation of Radial Immersion Ratio in Face Milling Using Cutting Force (정면 밀링에서 절삭력을 이용한 반경 방향 절입비의 실시간 추정)

  • Hwang, Ji-Hong;O, Yeong-Tak;Gwon, Won-Tae;Ju, Jong-Nam
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.8
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    • pp.178-185
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    • 1999
  • In tool condition monitoring systems, parameters should be set to a certain threshold. In many cases, however, the threshold is dependent on cutting conditions, especially the radial immersion ratio. In this presented is a method of on-line estimation of the radial immersion ratio in face milling. When a tooth finishes sweeping, a sudden drop of cutting force occurs. The force drop is equal to the cutting force that acting on a tooth at the swept angle of cut and can be acquired from cutting force signals in feed and cross-feed directions. Average cutting force per tooth period can also be calculated from cutting force signals in two directions. The ratio to cutting forces in two directions acting on a tooth at a certain swept angle of cut and the ratio of average cutting forces in two directions per tooth period are functions of the swept angle of cut and the ratio of radial to tangential cutting forces. Using these parameters, the radial immersion ratio is estimated. Various experiments are performed to verify the proposed method. The results show that the radial immersion ratio can be estimated by this method regardless of other cutting conditions.

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In-process Estimation of Radial Immersion Angle Using Cutting Force in Face Milling

  • Kwon, Won-Tae;Park, Deokki
    • Journal of Mechanical Science and Technology
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    • v.16 no.7
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    • pp.873-881
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    • 2002
  • In this paper, a on-line estimation method of the radial immersion angle using cutting force is presented. The ratio of cutting forces in feed and cross-feed directions acting on the single tooth at the immersion angle is a function of the immersion angle and the ratio of radial to tangential cutting force. It is found that the ratio of radial to tangential cutting force is not affected by cutting conditions and axial rake angle, which implies that the ratio determined by one preliminary experiment can be used regardless of the cutting conditions for a given tool and workpiece material. Using the measured cutting force during machining and predetermined ratio, the radial immersion ratio is estimated in process. Various experimental results show that the proposed method works within 5% error range.

Analysis of Radial Force on a Permanent Magnet Synchronous Motor Caused by Dimensional Variation (치수적 결함에 따른 PMSM의 법선방향 힘의 변화에 관한 연구)

  • Lee, Chee-Woo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.11
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    • pp.1990-1995
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    • 2010
  • Main reasons for causing vibration in a permanent magnet synchronous motor (PMSM) are torque ripple and radial force harmonics, and hence, both of them are undesirable in high-precision machine tools and accurate motion-control actuators. Recent research on radial force is the prediction of major vibration frequencies and modes in terms of motor design such as different winding types and a fractional slot number per pole in the stator. Also, proper phase current has been investigated for minimizing radial force harmonics. During the previous studies, all the motors are assumed to be ideally built up in terms of mechanical dimensions, but it is impossible due to dimensional variation within or outside tolerance in production. Therefore, in this paper, the effect of several key factors on radial force is examined and compared regarding manufacturing imperfection.