• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.663-664
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• 2006

In the electronic, medical, aerospace and automobile industries, many products and parts are manufactured by joining. Recently, as these get smaller, micro joining is becoming more and more important. In this study, micro wire-to-micro wire parallel joining was performed using single mode fiber laser. Maximum power of the fiber laser is 100 W. The CCD(Charge- Coupled Device, CCD) camera to observe the specimen was made up. The objective was applied to micro joining system to make a small spot size of laser beam. In order to control the target position, micro-multi-axis-stage was set up. This paper presents results for the single mode fiber laser joining of micro wires.

• Journal of the Korean institute of surface engineering
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• v.53 no.4
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• pp.138-143
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• 2020

In this study, we produced a coil of micro-pattern that can be used for electromagnetic wave absorber, heating material, wireless charging, sensor, antenna, etc. by using electrochemical additive manufacturing method. Currently, it contains research contents for manufacturing a micro pattern coil having practicality through control of process control variables such as applied voltage, distance between electrode, and nozzle injection. Circulation of the electrolyte through the nozzle injection control can significantly contribute to improving the surface characteristics of the coil because of minimizing voltage fluctuations that may occur during the additive manufacturing process. In addition, by applying the pulse method in the application of voltage, the lamination characteristics of the plated body were improved, which showed that the formation of a fine line width plays an important role in the production of a micro pattern coil. By applying the pulse signal to the voltage application, the additive manufacturing characteristics of the produced product were improved, and it was shown that the formation of a fine line width plays an important role in the production of a micro pattern coil.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.5
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• pp.118-127
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• 1997

In this study, We use microstep control to reduce vibration of step motor. Microstep control of step motor is usually thought of as an extension of conventional step motor control technology. The essence of micro stepping is that we divide the full step of a step motor into a number of substep called microstep and cause the stepmotor to move through a substep per input pulse. In ideal case, by controlling the individual phase currents of a two-phase step motor sinusoidally we can get uniform torque and step angle. But due to the nonlinear characteristics of the step motor, we need to compensate current waveform to improve the over-all smoothness of the conventional micro stepping system. We implement digital Pulse Width Modul- ation (PWM) driver to drive step motor and microphone was used for detecting vibration. Driver enables speed change automatically by increasing or decreasing micro stepping ratio which we call Automatic Switching on the Fly. To compensate the torque harmonics, neural network is applied to the system and we found compensated optimal input current waveform. Finally we can get smooth motion of step motor in a wide range of motor speed.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.409-413
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• 1986

This paper deals with a micro computer based CAD(Computer Aided Design/Drafting) software developed by SERI/KAIST. The objectives of this software(hereinafter, CADMATE) development are to develop a low-cost CAD/CAE system, which means the micro-computer based graphic handling software including its geometrical primitives, graphic editor, external interface and output(drawing) control routine.

• International Journal of Control, Automation, and Systems
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• v.3 no.3
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• pp.477-485
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• 2005

This paper is concerned with the development of a micro tensile testing machine for optically functional materials such as single or poly crystalline silicon and nickel film. This micro tensile tester has been developed for testing various types of materials and dimensions. PZT type actuation is utilized for precise displacement control. The specifications of the PZT actuated micro tensile testers developed are as follows: the volumetric size of the tester is desktop type of 710mm' 200mm' 270mm; the maximum load capacity and the load resolution in this system are IKgf and 0.0152mgf respectively and; the full stroke and the stoke resolution of the PZT actuator are $1000{\mu}m$ and 10nm respectively. Special automatic specimen installing and setting equipment is applied in order to prevent unexpected deformation and misalignment of specimens during handling of specimens for testing. Nonlinearity of the PZT actuator is compensated to linear control input by an inverse compensation method that is proposed in this paper. The strain data is obtained by ISDG method that uses the laser interference phenomenon. To test the reliance of this micro tensile testing machine, a $200{\mu}m$ thickness nickel thin film and SCS (Single Crystalline Silicon) material that is made with the MEMS fabrication process are used.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.4
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• pp.27-36
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• 2005

Some studies have shown that unstable factors are inherent in WEDM process, causing the instability of the discharging pulse to reach about 40∼60％ in normal machining. Transient stability is an important subject in WEDM process since there is a close relationship between stability and machining performance, such as the characteristics of a machined surface, machining speed and problem of instability like wire rupture phenomenon. Among the many machining parameters affecting WEDM machining state, three specific parameters (Vr, Ip, off time ) are major controllable variables that can be applied in transient stability control. And, this research investigates the implementation and analysis of real-time micro control of the discharging stability of WEDM (Wire Electric Discharge Machining) process.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.273-276
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• 2005

Performance analysis of a solid oxide fuel cell/micro gas turbine hybrid system is conducted at design-point and part-load conditions and its results are discussed in this study. With detailed considerations of the heat and mass transfer phenomena along various flow streams of the SOFC, the analysis based on a quasi-2D model reasonably predicts its performance at the design-point operating conditions. In case of part-load operations, performance of the hybrid system to three different operation modes(fuel only control, speed control, and VIGV control) is compared. It is found that the simultaneous control of both supplied fuel and air to the system with a variable MGT rotational speed mode is the optimum choice for the high performance operation. And then, the dynamic characteristics of a solid oxide fuel cell are briefly introduced.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.1 s.178
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• pp.201-208
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• 2006

Recently, there are many studies for the micro-machining using Piezo actuator. However, because of its step-by-step motion, it is nearly impossible to increase the machining accuracy for a circular path. To increase the accuracy, it is well known that it is necessary the finer and synchronous movement for x-y axes. Therefore, this paper proposes an adaptive control for finer movement of the actuator, and realizes a synchronous control for the x-y axes. The experimental results show that the machining accuracy is remarkably improved.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.649-651
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• 1999

This paper presents SNMP remote management system for power plants using micro-controller. Control board supporting LAN-based remote monitor and control is produced and MMI program on PC is also constructed. To expand into Internet, SNMP(Simple Network Management Protocol), the standard network management protocol of TCP/IP protocol suite, is ported to this control board consisted of micro-controller, 80c196KC, and LAN controller, Am7990DC. To overcome the constraints of CPU performance and memory capacity, TCP/P protocol suite is simplified and informations needed to management were implemented in accordance with MIB(Management Information Base) specified in RFC. Also monitoring software is constructed by Visual Basic.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.446-452
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• 2005

Recently, there are many studies for the micro-machining using Piezo actuator. However, because of its step by step motion, it is nearly impossible to increase the machining accuracy for a circular path. To increase the accuracy, it is well known that it is necessary the finer and synchronous movement for x-y axes. Therefore, this paper proposes a voltage control for finer movement of the actuator, and realizes a synchronous control for the x-y axes. The experimental results show that the machining accuracy is remarkably improved.