• 전기학회논문지
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• 제60권2호
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• pp.309-314
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• 2011

Outer rotor type in-wheel switched reluctance motor for Welfare neighborhood electric vehicle is researched. In-wheel system is to drive the electric vehicle without mechanical transmission, shaft, differential gears or other mechanical system. To calculate drive power for each wheels, the elder's and disable's safety driving conditions are considered. The designed outer rotor SRM has a 6-stator and 8-rotor pole. The determined dimensions as well as the stator and rotor pole arc are simulated and tested with CAD and finite element analysis to verify the performance of the proposed motor.

• 융복합기술연구소 논문집
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• 제7권2호
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• pp.1-5
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• 2017

The rotating electrodynamic wheel over a conductive plate produces thrust force as well as normal force. Specially, separating the conductive plate and spacing apart each part, the lateral stability of the rotating wheel is guaranteed due to the restoring force into neutral position. In this paper, the force characteristics of the electrodynamic wheel rotating over the conductive plate is analyzed using the finite element tool. First, the dominant parameters are identified considering the geometric configuration and the operating condition. And the sensitivity for the parameter deviation is quantified for the high force density. The above topology can be applied as an actuating principle for inter-city train as well as contact-free transfer device.

• 자동차안전학회지
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• 제15권2호
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• pp.13-20
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• 2023

This paper presents a fault tolerant control strategy for Steer-by-Wire (SbW) systems. Among many problems to be solved before commercialization of SbW systems, maintaining reliability and fault tolerance in such systems are the most pressing issues. In most previous studies, dual steering motors are used to achieve actuation redundancy. However, relatively few studies have been conducted to introduce fault tolerant control strategies using rear wheel steering system. In this work, an actuator fault in front wheel steering is compensated by active rear wheel steering. The proposed fault tolerant control algorithm consists of disturbance observer and sliding mode control. The fault tolerant control performance of the proposed approach is validated via computer simulation studies with Carsim vehicle dynamics software and MATLAB/Simulink.

• Tribology and Lubricants
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• 제28권1호
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• pp.19-26
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• 2012

Rolling contact fatigue of an urban railway wheel was analysed during its rolling. A FEM analysis was performed using a 3D modelling of rail and wheel, considering the slope of the rail and nonlinear isotropic and kinematic hardening behavior of the rail and the wheel. The maximum von-Mises stress and contact pressure between the rail and wheel were 656.9 MPa and 1111.4 MPa, respectively, under axial load of 85 kN with friction coefficient of 0. The fatigue initiation life prediction relationships by strain-lifetime (${\varepsilon}$-N) and Smith-Watson-Topper method were drawn for the wheel steel as follows: $N_i=7.35{\times}10^6{\times}SWT^{-3.56}$ and $N_i=5.41{\times}10^{-9}{\times}(\frac{{\Delta}{\varepsilon}}{2})^{-5.77}$. The fatigue lifetimes of the wheel due to rolling contact were determined to be infinite by ${\varepsilon}$-N and SWT methods.

• 한국철도학회논문집
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• 제11권2호
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• pp.203-210
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• 2008

바퀴와 BLDC전동기 일체형으로 구성되는 Hub Wheel 전동기는 감속기가 없는 직접 구동방식으로서 저소음 고효율의 운전이 가능하여 경전철의 구동부로 활용이 가능하다. 하지만 Hub Wheel 전동기는 속도계측을 위한 센서의 장착이 용이하지 않다. 전동기의 원활한 속도 제어를 위해서는 별도의 속도 계측을 위한 방법이 요구된다. 본 논문에서 입력이 적극 반영된 간단한 수학적 시스템 모델을 가지고 이산 칼만 필터를 사용하여 전동기 속도를 추정하고 이를 이용하여 속도제어를 하는 방법을 제시한다.

• 한국정밀공학회지
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• 제17권2호
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• pp.43-50
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• 2000

A CBN wheel was used for the highly efficient and precision grinding of the mold material(STD11). The grinding form accuracy by a CBN wheel is very excellent due to its low wheel wear, but grinding fragments resemble fine powders rather chips. A fine powders by this fragmentation can easily get attached to the wheel surface and therefore causing a loading. In order to prevent this fragmentation phenomena, the alumina stick is use to processing. Because the dressing with alumina stick should be interrupted for a processing, the automation of the processing and high productivity was very difficult. The investigation on the effect of Ultrasonic In-Process Dressing(ULID) on the grinding characteristics focuses in this Paper. This ULID method is that ultrasonic vibration in my Position of wheel is used to remove impurities on the wheel surface. Finally, the rate of surface roughness change in grinding by the ULID method was less than grinding without ultrasonic vibration. Loading phenomena by the ULID method were more prevented than grinding without ultrasonic vibration.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권5호
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• pp.253-259
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• 2005

Magnetic encoder with relatively low pulse per rotation is generally used for detecting speed of the high-speed rotating machine. It is due to the fact of the mechanical problems of vibration and bearing stiffness and also the limit of maximum output pulse of the mounted encoder. The magnetic encoder is divided into two types, that is, toothed gear-wheel method and magnetic wheel method according to the shape of the rotation disk. In case of detecting speed by the tooth gear-wheel, the encoder itself can be acted as the additional inertia where the number of tooth determining the output pulse and the width of the wheel detecting the change of the magnetic flux density are relatively enough large considering the volume of the rotating machine. While the magnetic wheel method has the limit of the magnetizing number of the ring magnet, there is relatively few, if nv, the influence of inertia on the machine. In this paper, it is proposed a simple magnetic wheel encoder suited for the high speed rotating machine and the method of signal processing and the output characteristics are examined through the V/F operation of max 48,000(rpm) and 2.4(KW) spindle motor.

• 한국정밀공학회지
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• 제19권10호
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• pp.195-201
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• 2002

This paper deals with the precision grinding for aspherical surface of optical parts. A parallel grinding method using the spherical wheel was suggested as a new grinding method. In this method, the wheel axis is positioned at a $\pi$/4 from the Z-axis in the direction of the X-axis. An advantage of this grinding method is that the wheel used in grinding achieves its maximum area, reducing wheel wear and improving the accuracy of the ground mirror surface. In addition, a truing by the CG (curve generating) method was proposed. After truing, the shape of spherical wheel transcribed on the carbon is measured by the Form-Talysurf-120L. The error of the form in the spherical wheel which is the value ${\Delta}x$ and $R{^2}{_y}$ inferred from the measured profile data is compensated by the re-truing. Finally, in the aspherical grinding experiment, the WC of the molding die was examined by the parallel grinding method using the resin bonded diamond wheel with a grain size of ＃3000. A form accuracy of 0.16${\mu}m$ P-V and a surface roughness of 0.0067${\mu}m$ Ra have been resulted.

• International Journal of Automotive Technology
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• 제8권2호
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• pp.211-217
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• 2007

The wheel slip control systems are able to control the braking force more accurately and can be adapted to different vehicles more easily than conventional ABS (Anti-lock Brake System) systems. In realizing the wheel slip control systems, real-time information such as the tire braking force at each wheel is required. In addition, the optimal target slip values need to be determined depending on the braking objectives such as minimum braking distance and stability enhancement. In this paper, a robust wheel slip controller is developed based on the adaptive sliding mode control method and an optimal target slip assignment algorithm is proposed for maximizing the braking force. An adaptive law is formulated to estimate the braking force in real-time. The wheel slip controller is designed based on the Lyapunov stability theory considering the error bounds in estimating the braking force and the brake disk-pad friction coefficient. The target slip assignment algorithm searches for the optimal target slip value based on the estimated braking force. The performance of the proposed wheel slip control system is verified in HILS (Hardware-In-the-Loop Simulator) experiments and demonstrates the effectiveness of the wheel slip control in various road conditions.

• 한국정밀공학회지
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• 제17권2호
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• pp.51-57
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• 2000

An automotive wheel bearing is one of the most important components to guarantee the service life of a passenger car. The endurance lift of a bearing is affected by many parameters such as material properties, heat treatment, lubrication conditions, temperature, loading conditions, geometry, internal clearance and so on. Under the same geometry and loading conditions, the internal clearance is the most effective parameters on the endurance lift of a bearing. Generally, bearings have the longest lift with a little negative internal clearance. But it is very difficult to measure and modify the internal clearance after a wheel bearing is assembled. In this paper, we analyze the effect of an assembling procedure on the clearance of wheel bearings and suggest a method to determine optimal clearance for automotive wheel bearings by selecting initial bearing clearance.