• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.487-490
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• 2003

In this research, we will devise an obstacle avoidance algorithm for a previously unmanned vehicle. Whole systems consist mainly of the vehicle system and the control system. The two systems are separated; this system can communicate with the vehicle system and the control system through wireless RF (Radio Frequency) modules. These modules use wireless communication. And the vehicle system is operated on PIC Micro Controller. Obstacle avoidance method for unmanned vehicle is based on the Virtual Force Field (VFF) method. An obstacle exerts repulsive forces and the lane center point applies an attractive force to the unmanned vehicle. A resultant force vector, comprising of the sum of a target directed attractive force and repulsive forces from an obstacle, is calculated for a given unmanned vehicle position. With resultant force acting on the unmanned vehicle, the vehicle's new driving direction is calculated, the vehicle makes steering adjustments, and this algorithm is repeated.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.1
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• pp.9-15
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• 2013

This paper presents a uniform analytical model by energy method and Fourier series expansion to analyze detent force in uneven magnetic field for permanent magnet linear synchronous motor (PMLSM). The model reveals that detent force in long-primary type is mainly influenced by non-ideal distribution of permanent magnet magnetic motive force, while nounified air-gap permeance makes a great impact on detent force of short-primary type. Hence, magnetic field similarity of motor design techniques referring rotary counterpart are adopted. For long-primary type novel method of splitting edge magnets is proposed to reduce end effects force, and optimal widths of edge tooth in short-primary type also verify the effectiveness of magnetic field similarity. The experimental results validate finite element analysis results.

• Journal of the Korean Society for Railway
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• v.9 no.6 s.37
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• pp.682-688
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• 2006

In this paper, a method which can deduce the traction farce or the braking force from the acceleration or the deceleration of the train, has been suggested. In the case of Korean high speed train (HSR-350x), the traction force and the braking forces have been obtained by using this method. It is proven that the proposed method is a very good tool in estimating the traction force or the braking force when the train starts or stops. Also, these forces on be used to calculate friction coefficients of mechanical brakes and the transmission efficiency of the traction system.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1349-1355
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• 2015

It is difficult to calculate the magnetic force of an object of magnetic material in contact with other objects using the existing methods, such as Maxwell stress tensor method, magnetic charge method, or magnetizing current method. These methods are applicable for force computation only when the object is surrounded by air. The virtual air-gap concept has been proposed for calculating the contact force. However, its application is limited to magneto-static system. In this paper, we present the virtual air-gap concept for contact surface force in the eddy-current system. Its validity and usefulness are shown by comparison between numerical and experimental examples.

• Transactions of Materials Processing
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• v.6 no.6
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• pp.482-488
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• 1997

New carbon equivalent equation for the better prediction for the better prediction of roll force in a continuous hot strip mill has been formulated by applying a neural network method. In predicting roll force of steel strip, carbon equivalent equation which normalize the effects of various alloying elements by a carbon equivalent content is very critical for the accurate prediction of roll force. To overcome the complex relationships between alloying elements and operational variables such as temperature, strain, strain rate and so forth, a neural network method which is effective for multi-variable analysis was adopted in the present work as a tool to determine a proper carbon equivalent equation. The application of newly formulated carbon equivalent equation has increased prediction accuracy of roll force significantly and the effectiveness of neural network method is well confirmed in this study.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.4
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• pp.369-374
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• 2009

In micro/nano-scale contacts in MEMS and NEMS, capillary and van der Waals forces generated around contacting micro-asperities significantly influence the performance of concerning device as they are closely related to adhesion and stiction of interacting surfaces. In this regard, it is of prime importance to accurately estimate the magnitude of surface forces so that an optimal solution for reducing friction and adhesion of micro/nano-surfaces may be obtained We introduced an effective method to calculate these surface forces based on topography information obtained from an atomic force microscope. This method was used to calculate surface forces generated in the contact interface formed between diamond-like carbon coating and $Si_3N_4$ ball. This method is shown to effectively demonstrate the influence of capillary force in the contact area, especially in humid atmosphere.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.3
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• pp.138-144
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• 2000

The detent force caused by the interaction of magnets with the teeth of a armature core deteriorates the driving performance of a permanent magnet linear synchronous motor. In this paper, we analyze the fields and forces of a linear synchronous motor with segmented or skewed magnet arrangement according to lateral overhang length of permanent magnets. For the analysis, the 3-dimensional equivalent magnetic circuit network method is used. The detent force and the static thrust are analyzed according to the segmented or skewed angle and the overhang length of permanent magnets, and the optimal angles that the detent force is minimized are found out in each case. The analysis results are compared with the experimental ones and shown a reasonable agreement.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.3
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• pp.22-29
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• 2004

Runout causes severe differences among cutting force waveforms due to changes of rotational radii. Thus a runout model must be included in a cutting force model to simulate cutting force accurately. In this paper, a runout modeling method and a measurement method using a dialgauge were developed, which were easy to apply. To calculate runout parameters, a computer program algorithm which obtained runout parameters from measurement values was developed. Cutting force waveforms simulated from cutting force model considering runout effect and measured from experiments had good agreements for their wave size and order.

• Journal of the Korean Society for Precision Engineering
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• v.1 no.3
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• pp.95-105
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• 1984

The purpose of this paper is to predict the cutting force, utilizing new model of double cutting edge which has normal rake angle and tool inclination angle. Changing side, back rake angle and side cutting edge angle in the new model. Three dimensional cutting force was obtained by the use of .eta. /c=i proposed by Stabler and energy method for three dimen- sional cutting force. Theoretical results has been calculated with development of optimization algorism which can be put into three dimensional theory, using the method of least square with orthogonal cutting data. IT is proved that three dimensional cutting force is to be predicted accurately only if orthogonal cutting force by equalizing theoretical result and experimental result has been calculated.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.10
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• pp.9-18
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• 2021

The cutting force in a cutting simulation is determined by the cutting conditions, such as cutting speed, feed rate, and depth of cut. The cutting force changes, depending on the material and cutting conditions, and is affected by the heat generated during cutting. The physical properties for predicting the cutting force use constitutive equations as functions of the hardening term, rate-hardening term, and thermal-softening term. To accurately predict the thermal properties, it is necessary to accurately predict the thermal-softening coefficient. In this study, the thermal-softening coefficient was determined, and the cutting force was predicted, using the response-surface method with the cutting conditions and the thermal-softening coefficient as factors.