• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.35S no.12
• /
• pp.36-45
• /
• 1998

In this paper, a method of on-line PI gain-tuninng is proposed for the speed control of brushless D.C. motor by investigating the pattern of input and output without estimating parameter. Proportional gain is tuned in the process to obtain a fast speed response by supplying the maximum constant input. And integral gain is appropriately tuned in the process of proportional control so that the response may be stably converged and the overshoot may be prevented. Therefore because both control and gain-tuning are executed concurrently, additional works that estimate parameters and so on aren't required in the proposed method. In the proposed method, both fast-response and overshoot problem are well solved, and it is more useful and convenient than existing auto-tuning methods in the speed control of D.C. motor. It is illustrated by simulations and experimental results that the proposed method is useful and stable.

• Journal of Environmental Impact Assessment
• /
• v.23 no.5
• /
• pp.364-378
• /
• 2014

Ecological Footprint (EF) in Korea has increased steeply over the past 50 years and, thus, the overshoot. It has been known that the main causes of the overshoot are population growth and the increase of the consumption intensity per person. In this study, the EF trend in Korea is analyzed for the past 50 years and it is found the major cause of the rapid increase of EF in Korea is the increase of the consumption intensity per person. Among the sectors of the consumption, Carbon Footprint (CF) from the energy consumption and Grazing Land Footprint and Fishing Grounds Footprint from the protein consumption are the major players for the increase. It is also found that if current trend of the EF per person would be maintained until 2060, EF in Korea would be expected to increase also continuously, despite of the decrease of the population from 2031. Therefore, the direction of the environmental management should be considered for inducing the change of the individual consumption patterns and the behavioral changes.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.18 no.4
• /
• pp.482-487
• /
• 2008

In case of flooding, the underwater flight vehicle (UFV) executes the blowing by blowing ballast tanks off using high pressure air (HPA), while it also uses control planes and a propulsion unit to reduce the overshoot depth caused by a flooding and blowing sequence. However, the conventional whole HPA blow-off method lets the body on the surface after blowing despite slight flooding. This results in the unnecessary mission failure or body exposure. Therefore, it is necessary to keep the body at the near surface by the blowing control while reducing the overshoot depth. To solve this problem, an adaptive blowing control algorithm, which is based on the decomposition method expanding the expert knowledge in depth control and the adaptive method using fuzzy basis function expansion (FBFE), is proposed. To verify the performance of the proposed algorithm, the blowing control of UFV is performed. Simulation results show that the proposed algorithm effectively solves the problems in the UFV blowing control system online.

• Journal of KIISE
• /
• v.42 no.9
• /
• pp.1162-1174
• /
• 2015

These days, the networks have exhibited HBDP (High Bandwidth Delay Product) characteristics. The legacy TCP slowly increases the size of the congestion window and drastically decreases the size of a congestion window. The legacy TCP has been found to be unsuitable for HBDP networks. TCP mechanisms for solving the problems of the legacy TCP can be categorized into the loss-based TCP and the delay-based TCP. Most of the TCP mechanisms use the standard slow start phase, which leads to a heavy packet loss event caused by the overshoot. Also, in the case of congestion avoidance, the loss-based TCP has shown problems of wastage in terms of the bandwidth and RTT (Round Trip Time) fairness. The delay-based TCP has shown a slow increase in speed and low occupancy of the bandwidth. In this paper, we propose a new scheme for improving the over shoot, increasing the speed of the bandwidth and overcoming the bandwidth occupancy and RTT fairness issues. By monitoring the buffer condition in the bottleneck link, the proposed scheme does congestion control and solves problems of slow start and congestion avoidance. By evaluating performance, we prove that our proposed scheme offers better performance in HBDP networks compared to the previous TCP mechanisms.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.10 no.5
• /
• pp.401-408
• /
• 2000

In this paper, we proposed a fuzzy controller that founded by the general feedback control with the new adjustment method when it's tuning. The general feedback controller is operated that supply to the plant making the control input multiplying the appropriate gain of controller on the error between the output of the plant and the reference, But proposed feedback fuzzy controller consist of three loops. The inner loop consists of plant and an ordinary feedback controller. The fuzzy inference of controller performed by the outer loops, which is composed of a fuzzy modeling and inference. We can observe that the output of control system converges toward the reference. Also, the behaviour of feedback fuzzy system is converged from the transient. That is, we verified that designed fuzzy controllers was adapted effectively through the experiments in the hydraulic motor system using floating point DSP processor.

• Journal of IKEEE
• /
• v.20 no.1
• /
• pp.103-106
• /
• 2016

PWM buck converters usually use a type-III error amplifier. Since this amplifier has a big capacitor with slow slew rate, they can generate an unintended large overshoot/undershoot at the output when a large load current change occurs. They can also respond slowly by varying the reference voltage. In order to increase battery lifetime, power supplies require a various range of load current and output voltage. PWM buck converter also should have a characteristic of both fast load response and reference tracking. This paper surveys a few recent techniques for reducing the settling time, and discusses their merits and limitations.

• Journal of IKEEE
• /
• v.26 no.3
• /
• pp.462-467
• /
• 2022

The feedback buffer structure is proposed to alleviate the overshoot and undershoot phenomenon and the regulation of the output voltage. The conventional LDO regulator undergoes a regulation voltage change caused by a constant load current change. An LDO regulator with a feedback voltage sensing structure operates in the input voltage range of 3.3 to 4.5 V and has a load current of up to 150 mA at output voltage of 3 V. According to the simulation results, a regulation value of 6.2 mV was ensured when the load current uniformly changed to 150 mA.

• Journal of IKEEE
• /
• v.27 no.3
• /
• pp.308-312
• /
• 2023

The gate current sensing structure was proposed to more effectively control the regulation of the output voltage when the LDO regulator occurs in an overshoot or undershoot situation. In a typical existing LDO regulator, the regulation voltage changes when the load current changes. However, the operation speed of the pass transistor can be further improved by supplying/discharging the gate terminal current in the pass transistor using a gate current sensing structure. The input voltage of the LDO regulator using the gate current sensing structure is 3.3 V to 4.5 V, the output voltage is 3 V, and the load current has a maximum value of 250 mA. As a result of the simulation, a voltage change value of about 12 mV was confirmed when the load current changed up to 250 mA.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.11
• /
• pp.1854-1859
• /
• 2016

Consider a linear fourth-order system with no zero that is represented in terms of four specific parameters: two damping ratios and two natural frequencies. We investigate several interesting questions about the maximum overshoot of the system with respect to the four-tuple parameters. Some remarkable results are presented.

• Proceedings of the KIEE Conference
• /
• 2008.04a
• /
• pp.191-192
• /
• 2008

도금 산업 분야에 이용되는 펄스 정류기의 경우 정밀한 도금을 위해 큰 용량에 오버슈트가 전혀 없는 아주 빠른 시스템 응답 특성을 요구한다. 이러한 특성을 만족시키기 위한 방안으로 ITAE로 성능지수를 이용한 PID 제어기 설계 방범을 시스템에 적용하여 PID 제기의 $K_D$, $K_P$, $K_I$을 찾는 과정을 알아보며, 선택된 제어 요소에 따라 시스템의 응답특성이 어떻게 변화되는지 모의실험을 통해 살펴본다.