• Journal of Mechanical Science and Technology
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• v.20 no.3
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• pp.345-357
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• 2006

By employing the concept of equivalent linkage, this paper presents an analytical method for analyzing the mechanical errors of disk cam mechanisms with a flat-faced follower. The resulting error equations do not really involve the location of the curvature center of the cam profile, and locating the curvature center of the cam profile is not essential. The resulting errors are significantly affected by the pressure angle, and the smaller pressure angle will result in the smaller mechanical error. In the worst case, owing to the joined effects of various design parameters, the accuracy of the follower motion may degrade considerably. For the oscillating follower case, all acceleration error functions have a sudden change at every beginning and at every end of the motion even though the theoretical follower displacement is cycloidal motion.

• Journal of Magnetics
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• v.16 no.1
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• pp.58-63
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• 2011

This paper presents design procedures of a transverse flux linear motor (TFLM). The minimum and maximum flux linkage was determined by the simplified equivalent magnetic circuit and estimated average magnetic flux density at the air gap region by considering the shape of applied magnetomotive force (MMF). With this information, the number of turns of each phase winding was calculated based on the amplitude of applied voltage and speed of a mover. The rated current, coil diameter, and winding area were obtained with the aid of an empirical formula for determining the required MMF. The usefulness of the proposed design method for TFLM is verified by the three-dimensional equivalent magnetic circuit network (EMCN) method and the experimental results of prototyped machine.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.2
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• pp.111-118
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• 2022

An electro-mechanical actuator (EMA) is an actuator that combines an electric motor with a mechanical power transmission elements, and it is suitable for urban air mobility (UAM) in terms of design freedom and maintenance. In this paper, the author presents the research results of the EMA that controls the rotor blade pitch angle of UAM. The actuator is based on an inverted roller screw and controls the blade pitch angle through a two-bar linkage. The dynamic equations for the actuator alone and the blade pitching motion with actuator were derived. For the latter, the equivalent moment of inertia is variable depending on the link angle due to the two-bar linkage. The variations of the equivalent moments of inertia are analyzed and compared in terms of the nut motion and the blade pitch motion. For an example model, the variation of the equivalent moment of inertia of the former is smaller than the latter, so it is judged that the dynamic equations derived from the point of view of the nut motion is suitable for the controller design.

• Progress in Superconductivity and Cryogenics
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• v.20 no.1
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• pp.15-18
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• 2018

In this paper, the magnetizing characteristics of the current limiting reactor (CLR) using $high-T_C$ superconducting (HTSC) module were analyzed. Since the saturation of iron core comprising the CLR using HTSC module deteriorates its current limiting operation, the design of the CLR using HTSC module considering the magnetizing characteristics is needed. For the analysis on the magnetizing characteristics, the flux linkage and the magnetizing current of this CLR using HTSC module were derived from its electrical equivalent circuit. Through the analysis on the linkage flux versus the magnetizing current, obtained from the short-circuit tests, the suppressing effect of the iron core's saturation was discussed.

• Transactions on Electrical and Electronic Materials
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• v.18 no.3
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• pp.159-162
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• 2017

In designing the autotransformer type superconducting fault-current limiter (SFCL), one must consider that the iron core can be saturated for the SFCL to have effective fault-current limiting operation. In this paper, to examine the saturation of the iron core comprising SFCL during the fault period, the linkage flux and the magnetizing current of the SFCL were derived from the electrical equivalent circuit with the nonlinear exciting branch. By analysis on the linkage flux versus the magnetizing current of the autotransformer type SFCL, calculated from the short-circuit tests, the design condition for the suppression of the iron core's saturation was discussed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.1
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• pp.34-40
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• 2012

Flux linkage of phase windings or phase inductance is an important parameter in determining the behavior of a switched reluctance motor (SRM) [1-8]. Therefore, the accurate prediction of inductance at aligned and unaligned rotor positions makes a significant contribution to the design of an SRM and its analytical approach is not straightforward due to nonlinear flux distribution. Although several different approaches using a finite element analysis (FEA) or curve-fitting tool have been employed to compute phase inductance [2-5], they are not suitable for a simple design procedure because the FEA necessitates a large amount of time in both modeling and solving with complexity for every motor design, and the curve-fitting requires the data of flux linkage from either an experimental test or an FEA simulation. In this paper, phase inductance at aligned and unaligned rotor positions is estimated by means of numerical method and magnetic equivalent circuit as well, and the proposed approach is analytically verified in terms of the accuracy of estimated inductance compared to inductance computed by an FEA simulation.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.601-607
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• 1998

This paper presents the efficient 2-D linear brake analysis model which can compensate the lateral leakage flux by changingng the airgap length and magneto-motive force(MMF). The linkage flux of the 2-D analysis is larger than that of 3-D analysis. This is caused by the assumption in 2-D analysis that geometric and physical values are constant along the perpendicular direction(z) to the analysis region. The equivalent MMF have been calculated from the linkage flux difference between the 2-D and 3-D analyses which are performed at zero velocity. The performances of the linear brake have been analyzed effectively by using the compensated 2-D models without using 3-D FEM.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.154-156
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• 1999

A Linear Stepping Motor(LSM) can operate open loop control mode similarly to a rotary stepping motor. The linear motion without any mechanical linkage in the LSM results in several advantages for precise positioning actuators. However, to realize the more stable and higher speed control without hunting, it is necessary to derive an equivalent circuit to explain the steady-state and transisent characteristics in order to find an adequate control rule for high performance control of the LSM. In this paper, magnetic equivalent circuit is obtained, based on the structure of the LSM, and then the electric equivalent circuit of the LSM is derived by solving equations for the magnetic equivalent circuit. The 1-step response characteristic of the LSM is analyzed by the ACSL with the voltage equations, the force equations, the force equations and the kinetic equation.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.83.2-83
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• 2001

This paper presents a new formulation approach to reduce computational burden of the direct kinematics of 6-dof haptic devices with three sets of a parallel-serial linkage. Their direct kinematics has been formulated through employing the Denavit-Hartenberg notation, which results in complicated formulation procedures and heavy computational burden. For reducing these problems, this paper reconfigures the haptic devices into an equivalent kinematic model of the 3-6 Stewart-Gough Platform that has three connecting joints on the moving platform. Moreover, the direct kinematics of the 3-6 Platform can be effectively formulated by using the proposed Tetrahedron Approach.

• Journal of Electrical Engineering and Technology
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• v.8 no.5
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• pp.1221-1226
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• 2013

In this paper, the equivalent circuit for the efficiency calculation by precise estimation of the linkage flux, inductance and iron loss resistance was calculated accurately. In addition, the driving characteristics according to the current phase angle are analyzed and the maximum efficiency point is calculated. And then, analyzed and experimental values of the efficiency were compared. So, causes of error were expected to be vibration and noise by harmonic distortion of the voltage and current, and mechanical loss of dynamometer. In addition, the driving characteristics according to the current phase angle are analyzed and the maximum efficiency point is calculated.