• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.6
• /
• pp.25-35
• /
• 1999

This paper presents a control gain tuning scheme for multi-axis PID control systems by Taguchi method. As an experimental set-up, a parallel mechanism machine tool has been selected. This machine has eight servodrives and each servodrive has four control gains, respectively. Therefore, total 32 control gains have to be tuned. Through a series of design of experiments, an optimal and robust set of PID control gains is tuned. The index of the sum of position error and velocity error is reduced to 61.4% after the experimental gain tuning regardless of the feedrate variation.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.36D no.1
• /
• pp.15-21
• /
• 1999

A new design of RF automatic gain control amplifier with low phase shift attenuator is proposed. By using the RF AGC amplifier, the output level of amplifier becomes to be constant. The error is 0.1dB. In addition, for arbitrary RF input power, it is possible to design the gain of amplifier to be fixed. If the constant gain is maintained, it is more reliable to make wanted IMD(Intermodulation Distortion) characteeristic amplifier.

• Journal of Korea Multimedia Society
• /
• v.5 no.6
• /
• pp.753-758
• /
• 2002

In this paper, low voltage 3V CMOS programmable gain amplifier(PGA) for using in the transmitter and receiver of ADSL analog front-end is designed. The designed receive PGA is connected with 1.1MHz continuous lowpass fillet and controls the gain from 0dB to 30dB. And also the transmitter PGA is connected with 138KHz lowpass filter and controls the gain from -15dB to 0dB. The gain of All PGAs can be programmed by digital logic circuits and main controller. The designed PGAs are verified using HSPICE simulation with $0.35\mu{m}$ CMOS parameter.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.5 no.3
• /
• pp.64-72
• /
• 1995

This paper proposes how to tune the gains of PI controllers in case of gain change in a process control system. Controllers of PI type have been used in industry and the gains of the controllers have been tuned by expert engineers. It, therefore, takes much time and efforts to tune the controllers. It is more difficult to find gains of multi-loop processes. The tuning method of a fuzzy tuner in this paper is developed based on the assumptions that the PI controllers are of analog type and are tuned off-line, and that the characteristic values must be supplied for the tuner. A Tuner using Fuzzy Logic(FLT1 is capable of showing presentlpast states of a process control system and finding gains of PI controllers. The verfication of the FLT is shown by various experiments.

• Journal of the Institute of Convergence Signal Processing
• /
• v.3 no.1
• /
• pp.74-79
• /
• 2002

Many control techniques have been proposed in order to improve the control performance in discrete-time domain control system. In control system using these techniques, the response-characteristic of system is dependent on the gains of the controller. Specially, There is a need to readjust the gain of controller when the response of system is changed by disturbance or load fluctuation. In this paper, I-PD controller and pre-compensator are designed by multilayer neural network. The gains of I-PD controller and pre-compensator are adjusted automatically by back propagation algorithm when the response characteristic of system is changed under a condition. Applying this control technique to the position control system using a DC servo motor as a driver, the control performance of controller is verified by the results of experiment.

• 전기의세계
• /
• v.36 no.9
• /
• pp.658-664
• /
• 1987

최적이득을 구하는 해석적인 방식으로 안정여유에 의한 최적화방식과 공액경사법에 의한 최적화방식을 살펴보았으며, 두방식을 비교해 보면 몇몇 문제점이 존재하나 다음의 몇가지 점에서 공액경사법에 의한 최적화방식이 더 우수하다는 것을 알 수 있다. 1) 제어루우프내의 제어기 수에 관계없이 이 방식을 쉽게 적용할 수 있다. 2) 시스템을 수식으로 모델링할 때 거의 간략화함이 없이 표현하므로 실제 시스템과의 오차를 줄일 수 있다. 3) 평가함수 내의 가중치를 조정하여 원하는 과도응답을 가지는 최적이득으로 유도할 수 있다. 공액경사법에 의한 최적화방식은 벡터제어나 전류제어PWM등 보다 복잡한 제어루우프에도 쉽게 적용시킬 수 있으며 직류기 및 서보전동기의 속도 및 위치 제어시스템에도 적용이 가능하다.

• Journal of Digital Contents Society
• /
• v.8 no.3
• /
• pp.341-346
• /
• 2007

The purpose of this paper is to propose the design of VADSM(Value-Added Digital Speaker Module) which tunes up the speaker unit by measuring the speaker's frequency responses and controlling EQ band. This module can reduce audible distortions at particular frequency band and improve some flatness in the speaker's frequency response. VADSM is composed of DSP AMP and speaker unit. When a speaker transforms electrical signal to sound, the magnitude response at some frequencies are more or less than normal level. So, DSP AMP can be used to adjust those magnitudes up or down by controlling its EQ bands.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1987.10a
• /
• pp.159-164
• /
• 1987

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.7
• /
• pp.797-803
• /
• 2012

Proportional solenoid valves are a modulating type that can control the displacement of valves continuously by means of electromagnetic forces proportional to the solenoid coil current. Because the solenoid-type modulating valves have the advantages of fast response and compact design over air-operated or motor-operated valves, they have been gaining acceptance in chemical and power plants to control the flow of fluids such as water, steam, and gas. This paper deals with the auto tuning of the position controller that can provide the proportional and integral gain automatically based on the dynamic system identification. The process characteristics of the solenoid valve are estimated with critical gain and critical period at a stability limit based on implemented relay feedback, and the controller parameters are determined by the classical Ziegler-Nichols design method. The auto-tuning algorithm was verified with experiments, and the effects of the operating point at which the relay control is activated as well as the relay amplitude were investigated.

• The Journal of the Acoustical Society of Korea
• /
• v.24 no.5
• /
• pp.238-247
• /
• 2005

In this Paper. we Presents subband design techniques of a compensating filter and adaptive feedback canceller for the digital hearing aid. The sensorineural hearing loss has a hearing threshold that shows a nonlinear characteristic in frequency domain. and its compensation suffers from an echo that produced by an undesired time varying feedback path. Therefore. the digital hearing aid requires the compensator that can adjust gains nonlinearly in frequency bands and eliminate the echo rapidly In the Proposed digital hearing aid. the compensating filter is designed by the adaptive system identification method in subband structure, and the adaptive feedback canceller is designed by the subband affine projection algorithm. The designed compensation filter can control the nonlinear gain in each subband respectively, therefore precise compensation is possible. And the feedback canceller using the subband adaptive filter achieves fast convergence rate. The Performances of the Proposed method are verified by computer simulations as comparing with the behaviors of the previous trials.