• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.299-306
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• 2016

In this paper, a method of shape prediction of an endoscope handling robot that can imitate a surgeon's behavior using a sensor network is suggested. Unit sensors, which are composed of a 3-axis magnetometer and 3-axis accelerometer pair comprise the network through CAN bus communication. Each unit of the sensor is used to detect the angle of the points in the longitudinal direction of the robot, which is made from a flexible tube. The signals received from the sensor network were filtered using a low pass Butterworth filter. Here, a Butterworth filter was designed for noise removal. Finally, the Euler angles were extracted from the signals, in which the noise was filtered by the low path Butterworth filter. Using this Euler angle, the position of each sensor on the sensor network is estimated. The robot body was assumed to consist of links and joints. The position of each sensor can be assumed to be attached to the center of each link. The position of each link was determined using the Euler angle and kinematics equation. The interpolation was carried out between the positions of the sensors to be able to connect each point smoothly and obtain the final posture of the endoscope in operation. The experimental results showed that the shape of the colonoscope can be visualized using the Euler angles evaluated from the sensor network suggested and the shape of serial link estimated from the kinematics chain model.

• Proceedings of the KIEE Conference
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• 2000.07e
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• pp.132-135
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• 2000

본 논문에서는 ADSL 모뎀용 아날로그 Front-end 단에 사용되는 Rx과 Tx단의 연속시간 Gm-C 고역 및 저역 통과 필터를 설계하였다. 설계된 Tx의 아날로그 저역 통과 필터는 차단 주파수, 138kHz의 3차 Elliptic 함수를 이용하였고, Rx에서는 138kHz의 3차 Butterworth 고역 필터와 1.1MHz의 3차 Butterworth 저역 필터를 이용하여 설계하였다. 설계된 모든 필터는 주파수와 이득의 튜닝을 용이하게 하고 잡음특성에 유리한 연속시간 Gm-C 실현 법을 이용하여 구현하였다. Gm-C 실현 법을 이용하기 위하여 선형 특성이 개선된 Gm-C 적분기를 새롭게 설계하여 이용하였다. 설계에 활용된 파라미터는 IDEC에서 제공한 아남의 $0.25{\mu}m$ CMOS 1-poly, 5-metal 공정 파라미터를 이용하였으며, 2.5V의 저전압으로써 회로로 구성하였고 HSPICE를 이용하여 검증하였다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.2
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• pp.63-68
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• 1999

This pper describes a digital sensorless drive of permanent magnet brushless DC motors. In order to detect in real time the rotor positions of which Emf becomes zero, terminal voltages are sampled during PWM duty cycle. This method generates detection error in indirect sensed position, which is the harmonic component of PWM frequency. In this paper, the drive adopted Butterworth low pass filter for rejection of the sensing error and for accurate estimation of commutation time. Analytical design process of the digital filter is proposed and the experimental results show that the performance of the proposed sensorless drive is superior to that of the sensorless drives without filterint.

• 대한핵의학회:학술대회논문집
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• 1999.11a
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• pp.32.1-32.1
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• 1999

• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.4
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• pp.11-17
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• 1980

This paper describes realization of digital filter using $\mu$p controler and discusses measured characteristics of this filter, The idea of P. L. implementation[1] is used in realization, and in this system we utilize a DMA and arithmatic control program of $\mu$p. In this way, we can get more flexible capability than the basic PL method, and higher speed than a filter using general purpose $\mu$p in hardware, Furthermore, we get a 15 KHz sampling frequency(fs) as speed limit in real time processing, and know that this limitation is restricted by execution time (58$\mu$ sec) of DMA control statement. As for filter charateristics, maximum stop band frequencies (fsp) are 1665 Hz, 1445 Hz in Butterworth and Tchebichef approximation, respectively, when fs = 14 KHz. Measured errors between the design specification and the actual result are 0.2dB, 0.1 dB in pass band (when cufoff frequency is 500Hz),-1.1dB (when fsp is 1000Hz), 0.4dB(when fsp is 750 Hz) in stop band frequency of Butterworth and Tchebichef, respectively.

• Structural Engineering and Mechanics
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• v.23 no.4
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• pp.409-430
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• 2006

The aim of this study is to investigate the reliability of strong motion records processed by causal and acausal Butterworth filters in comparison to the results obtained from a synthetic accelerogram. For this purpose, the fault parallel component of the Bolu record of the Duzce earthquake is modeled with a sum of exponentially damped sinusoidal components. Noise-free velocities and displacements are then obtained by analytically integrating the synthetic acceleration model. The analytical velocity and displacement signals are used as a standard with which to judge the validity of the signals obtained by filtering with causal and acausal filters and numerically integrating the acceleration model. The results show that the acausal filters are clearly preferable to the causal filters due to the fact that the response spectra obtained from the acausal filters match the spectra obtained from the simulated accelerogram better than that obtained by causal filters. The response spectra are independent from the order of the filters and from the method of integration (whether analytical integration after a spline fit to the synthetic accelerogram or the trapezoidal rule). The response spectra are sensitive to the chosen corner frequency of both the causal and the acausal filters and also to the inclusion of the pads. Accurate prediction of the static residual displacement (SRD) is very important for structures traversing faults in the near-fault regions. The greatest adverse effect of the high pass filters is their removal of the SRD. However, the noise-free displacements obtained by double integrating the synthetic accelerogram analytically preserve the SRD. It is thus apparent that conventional high pass filters should not be used for processing near-fault strong-motion records although they can be reliably used for far-fault records if applied acausally. The ground motion parameters such as ARIAS intensity, HUSID plots, Housner spectral intensity and the duration of strong-motion are found to be insensitive to the causality of filters.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.105-112
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• 2002

In this paper, a servo filter design for the gimbal engine actuator system of KSR-III(Korea Sounding Rocket-III) is considered. A reasonable filter structure is determined based on the actuator analytic models. The servo filter consists of a 2-nd order lowpass filter and a 1-st order compensator. The lowpass filter is required to protect the actuator from high frequency vibration, and the compensator to enhance the resulting stability. A Butterworth type servo filter is considered as the simplest one. The final servo filter type is determined by evaluating simultaneously both high frequency gain reduction performance and the corresponding KSR-III stability margin. Consequently it is revealed that a notch type servo filter located on the error between command signal and feedback signal in the control loop is very effective. Later, based on the proposed servo filter type, an onboard servo filter hardware of KSR-III will be designed and tested.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.817-822
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• 1992

Distortion analysis of digital filters for the ECG signal processing is presented. Several band pass and band reject filters are designed for the analysis. Computer simulations are performed to compare the distortions of the Butterworth type filters and linear phase optimal fitters. The designed filters are applied to power line interference cancelling in ECG signals.

• Journal of Navigation and Port Research
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• v.35 no.1
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• pp.1-7
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• 2011

This paper describes the development of Data Acquisition System (DAS) to obtain the vessel and weather information needing to evaluate collision risks levels between Mokpo harbor bridge and passing vessels. DAS consists of Signal Receiving and Processing Unit to obtain the data sets of passing vessels and weather status, Networking Unit to transmit and distribute the acquisition data sets and Data Management Unit. Through the field tests on the deck of shuttle car ferry between Mokpo Port Passenger Terminal and An-Jua island, Sinan-Gun, we found that the DAS can provide useful data sets for adequate the collision risk evaluation. In addition, the noise-like data sets appeared in the weather data can be suppressed fully using 5-th order Butterworth digital filter.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.5
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• pp.69-74
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• 1985

In this paper five-order Butterworth Low pass active RC filter is designed by using FDNR (Frequency Dependent Ncgative Resistor) Method from LC ladder filter having the lowest sensitivity. In process of Transformation to SCF (Switched Capacitor Filter) from active RC filter, Bilinear Z Transfomation method is utilized. By the design of SCF using the bilinear Z transform method the problem of aliasing can be avoided, but the frequency distortion is generated. The transformation from analog filter to digital filter is not equal in the region of the cut off frequency caused by this effect. Avoiding the problem of this effect, we use prewarping method. The result shows that the prewarped SCF makes more remarkable improvement in the frequency distortion than SCF which is transformed by using bilinear Z transform.