• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.406-409
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• 1997

An economical 4-axis CNC controller employing step motors is designed and implemented in this paper. By using the inherent ability of holding position of the motor, the CNC controller uses open-loop control for removing trajectory error and for a simple hardware. Each drive of axis has an 8-bit microprocessor 89C52 and a PC controls the axes and pendant by means of RS232C serial communication. Backlash is also compensated at the axis controller. While compensating the backlash, the feed rate becomes zero in order to minimize trajectory error. The trajectories of 16ms interval are computed on PC and are sent to motor drives. In the drives, the trajectories are linearly interpolated for 2ms interval. The developed CNC does not require add-on specific motion card on PC. From the experimental results, the validity of the CNC controller based on step motor is proved.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.709-712
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• 2003

The existing technical limitation makes engineer imitate nature to solve engineering problems. Recently Micro Air Vehicle(MAV) imitating the mechanism of birds or insects is being developed. Especially Ultra Flite supported by DARPA is studying hummingbird aerodynamics to relate that information to MAV. To drive MAV bender piezoelectric(PZT) actuators are used due to the convinience of control and the small size. But the displacement of the PZT actuators are very small, and the wing driving mechanism which amplifies the stroke generated by the PZT actuators has constraints in design and manufacture because of the small dimension. In this paper a wing design concept and a efficient driving mechanism are proposed. Electroactive polymers(EAPs) are used as wing mechanism actuators. Using OpenGL the mechanisms are simulated graphically. Also a prototype actuator is being developed and verified by digital Mockup with CATIA. Basic kinematics of the mechanism is studied.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.3
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• pp.187-192
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• 2005

This paper presents the design of the Automatic Gain Control (AGC) system for the drive axis of a electro-magnetic driven cylinder gyroscope. The simulation and experimental results show that the designed AGC excites the cylinder at its natural frequency and maintains a specified amplitude of oscillations, and also track the natural frequency shifts due to temperature variations. The sensing performance of the AGC driven gyroscope is shown to be greatly improved compared to that of the open-loop driven one.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.287-289
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• 1995

In this paper, We applied the $\mu$-stepping method on the Phase Excitation Sequence of Hybrid type LPM. Linear Pulse Motor can opeate in an open loop control as an effective positioning actuator. PWM driver was used for low power loss and automatically adjusted voltage at rate current. Finally we find that through the position-velocity for timing Triangular and Trapezoidal Profile are very affected by velocity and acceleration parameter.

• Journal of Drive and Control
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• v.12 no.4
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• pp.15-20
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• 2015

Unlike a typical metal spring, a gas spring uses compressed gas contained in a cylinder and compressed by a piston to exert a force. A common application includes automobiles where gas spring are incorporated into the design of open struts that support the weight of tail gate. They are also used in furniture such as office chairs, and in medical and aerospace applications. The gas spring works by the application of pressurized gas (nitrogen) contained in a cylinder. The internal pressure of the gas spring greatly exceeds atmospheric pressure. This differential in pressure exists at any rod position and generates an outward force on the rod, making the gas spring extend. In this paper, we investigated the dynamic characteristics of a gas spring on an automotive tail gate system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.39-40
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• 2006

The operation of wheel-loader is mainly divided into steering and excavating. The existing wheel-loader is used by handle for steering operation and by joystic for excavating operation. When we do steering and excavating operation simultaneously, we feel so uncomfortable because we have to use handle and joystic simultaneously. Therefore, we need to develop eletro-joystic steering system instead of hydraulic-handle steering system. So we can improve driving convenience in industrial field. This paper analyze spool of steering wheel and joystic and drive open area diagram. As a result, we can know characteristics of each valve before developing new electro-joystic steering system for wheel-loader.

• International Journal of High-Rise Buildings
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• v.5 no.2
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• pp.127-136
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• 2016

As the great urban migration continues to drive the growth of cities worldwide, global companies are seeking new approaches to the urban workplace and corporate campus. In light of environmental and economic imperatives to develop taller and denser central business districts, a key challenge is merging contemporary workplace concepts, which emphasize large, open floors and high levels of connectivity, with high-rise typologies with smaller floor plates set around center cores. This paper traces the evolution of the corporate campus and emerging design strategies for translating contemporary workplace models into a vertical campus typology that allows companies to realize the benefits of urban locations, while contributing to a more sustainable future.

• Journal of electromagnetic engineering and science
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• v.8 no.1
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• pp.6-11
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• 2008

Advances in low power design open the possibility to harvest energy from the environment to power electronic circuits. Electrical energy can be harvested from piezoelectric transducer. Piezoelectric materials can be used as mechanisms to transfer mechanical energy usually vibrating system into electrical energy that can be stored and used to power other devices. Micro- to milli-watts power can be generated from vibrating system. We developed definitive and analytical models to predict the power generated from a cantilever beam attached with piezoelectric transducer. Analytical models are pin-force method, enhanced pin-force method and Euler-Bernoulli method. Harmonic oscillations and random noise will be the two different forcing functions used to drive each system. It has been selected the best model for generating electric power based upon the analytical results obtained.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.360-363
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• 2001

The conventional 60(Hz) power supply for driving magnetron in microwave oven has disadvantages of heavy weight and low efficiency due to 60(Hz) High Voltage Transformer(HVT), capacitor and the phase control of thyristors with open-loop controller. To alleviate these disadvantages, this paper proposes a 20(kHz) phase-shifted(PS) Full-Bridge(FB) Zero- voltage-Switched(ZVS) PWM converter to drive a 600(W) magnetron in an 1(kW) microwave oven and to control the average anode current.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.413-414
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• 2017

영구자석 동기전동기 구동 인버터 시스템 내 스위치 고장은 다양한 조합으로 발생한다. 특히 스위치 개방고장의 경우 다른 전기 부품에 과전류를 유발하여 전체 시스템에 심각한 2차 손상을 초래한다. 본 논문에서는 개방고장 진단 알고리즘의 복잡성을 완화하기 위해 고장 그룹을 분류하여 고장 발생 시 false alarm의 영향을 받지 않고 간단하고 체계적인 방식으로 고장을 식별할 수 있는 기법을 제안한다. 스위치의 개방 고장으로 영구자석 동기전동기 구동 시스템 내 PWM 전압원 인버터의 신뢰성을 향상시키기 위해 3중 스위치 개방고장 진단 및 검출 기법을 제시한다. 제안된 기법은 기존의 개방고장 진단방법과 달리 정보처리를 위해 Moving Filter를 사용함으로써 연산부하를 증가시키지 않고 신속한 고장 검출이 가능하며 별도의 하드웨어 구성없이 구현이 가능하다. 제안된 기법의 안정성과 유효성이 시뮬레이션을 통해 입증된다.