• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.5
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• pp.35-40
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• 2005

An experimental Investigation of the basic characteristics of a micro-cantilever sensor was performed by inspecting the amplitude and frequency characteristics of a commercial tuning fork (TF). Application of acetone and ethanol with a volume of $1{\mu}l$ on the tine of a vibrating tuning fork causes immediate response in its amplitude and frequency characteristics. It has been shown that the tuning fork has ability to recognize a chemical agent with high sensitivity. The theoretical sensitivity of mass loading is in the range of $\~0.1Hz/ng$. Quartz tuning forks are routinely made using standard microfabrication process, thus suggesting the possibility of microfabrication of micro quart sensors.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.3
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• pp.26-30
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• 2001

Controller refinement scheme to improve the performance of a conventional system automatically in frequency domain is proposed. The controller automatic tuning method features using experimental frequency responses of the conventional closed-loop system, the conventional controller, and the improved closed-loop system, instead of poorly modeled plant due to non-linearities and disturbances. The improved closed-loop system characteristics is automatically acquired by the con-ventional closed-loop system characteristics and the proposed performance index in system bandwidth. And the proper controller is realized by least squares approximation in frequency domain. To testify the usefulness of the approach, the path tracking control of robot arm is performed. Experimental results and analytic results are well-matched.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.136-139
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• 2000

Controller refinement scheme to improve the performance of a conventional system automatically in frequency domain is proposed. The controller automatic tuning method features using experimental frequency responses of the conventional closed-loop system, the conventional controller, and the improved closed-Imp system; instead of poorly modeled plant due to non-linearities and disturbances. The improved closed-loop system characteristics is automatically acquired by the conventional closed-loop system characteristics and the proposed performance index in system bandwidth. And the proper controller is realized by least squares approximation in frequency domain. To testify the usefulness of the approach, experimental results of robot path-tracking control applied with various controllers is used, and then is analyzed with respect to a equivalent proportional controller. Experimental results and analytic results are well-matched.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.1
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• pp.40-46
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• 1999

A self-tuning FPID(Fuzzy Proportional Intergral Derivative) controller fo load frequency control of 2-area power systemis proposed in this paper. The paramters of the proposed self-tuning FPID controller are self-tuned by the proposed fuzzy inference technique. Therefore in this paper the fuzzy inference technique of PID gains using PSGM(Product Sum Gravity Method) is presented and is applied to the load frequency control of 2-area power system. The computer simulation results show that the proposed controller give better more control characteristics than convention-al PID, FLC under load changes.

• Korean Journal of Optics and Photonics
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• v.5 no.1
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• pp.80-83
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• 1994

A Littman type dye laser oscillator inserted a wedge prism was constructed. Accurate frequency tuning was achieved by the rotation of the wedge prism instead of the tuning mirror. Frequency tuning rate was about 20 GHz/deg. and the synchronous tuning of 70 GHz without mode-hop was achieved. ieved.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.5
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• pp.478-484
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• 1990

An automatic tuning method of a PID controller which is used for single input single output processes is proposed. In the proposed tuning method, the frequency response data model is adopted along with the performance index which is an integral of time weighted square error between reference model and process frequency response data model for tuning. This method is easier to retune when either the process dynamics is changed or the reference model is changed. Finally, an example is provided to show the usefulness of the method.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.10
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• pp.17-22
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• 2007

This paper presents a baseband complex bandpass filter for PHS applications with a new automatic tuning method. The full-CMOS PHS transceiver is implemented by adopting the Low-IF architecture to overcome the DCoffset problems. To meet the Adjacent Channel Selectivity (ACS) performance, the 3rd-order Chebyshev complex bandpass filter is designed as the baseband channel-select filter. The new corner frequency tuning method is proposed to compensate the process variation. This method can reduce the noise level due to MOS switches. The filter was fabricated using a 0.35{\mu}m$ CMOS process, and the power consumption is 12mW.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1857-1862
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• 2008

Resonant frequency tuning of micro devices is essential to achieve performance uniformity and high sensitivity. Previously reported frequency tuning methods using electrostatic force or mass deposition are not directly applicable to non-conducting polymer devices and have limitations such as dielectric breakdown or low tunable bandwidth. In this paper, thermally frequency-tunable microactuators with poly-dimethylsiloxane membranes are proposed. Permanent and/or nonpermanent frequency tunings are possible using a simple temperature control of the device. Resonant frequency and Q-factor variations of devices according to temperature change were studied using a micro heater and laser Doppler vibrometer. The initial resonant frequencies determined by polymer curing and hardening temperatures are reversibly tuned by thermal cycles. The measured resonant frequency of 9.7 kHz was tuned up by ${\sim}25%$ and Q-factor was increased from 14.5 to 27 as the micro heater voltage increased from 0 to 70 V.

• Proceedings of the IEEK Conference
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• summer
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• pp.218-220
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• 2004

A new wide-band VCO topology using Miller capacitance is proposed. Contrary to conventional VCO using the Miller capacitance where the variable amplifier gain is negative, the proposed VCO uses both the negative and positive variable amplifier gain to enhance the frequency tuning range significantly. The proposed VCO is simulated using HSPICE. The simulations show that 410MHz and 220MHz frequency tuning range are obtained using the negative .and positive variable amplifier gain, respectively. The tuning range of the proposed VCO is $23\%$ of the center frequency(2.8GHz). The phase noise is -104dBc/Hz at 1MHz offset by simple model. The operating current is only 3.84mA at 2.5V power supply.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.88-91
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• 2005

Although the MEMS element is made through a very precise manufacturing process, usually there is the difference between the modeling design and the actual product. So tuning is required. Through the frequency tuning(changing the characteristics of device), we can calibrate the fabrication error and uncertainty. I'll propose the method of changing the natural frequency through the imposing the axial force on the anchor part to separate the sensing part and the tuning part. When the shape of section is the form of rectangular, the degree of the natural frequencies' change under axial force appears D be different. Applying a tuning force of 30 $\mu$N, the natural frequencies' difference can be reduced by 5 percent.