Hyun-Seob Cho

A Study on the Speed Control of Induction Motor using a PID Controller and Neural Network Controller

Robust control for DC servo motor is needed according to the highest precision of industrial automation. However, when a motor control system with PID controller has an effect of load disturbance, it is very difficult to guarantee the robustness of control system. As a compensation method solving this problem, in this paper, PID-neural network hybrid control method for motor control system is presented. The output of neural network controller is determined by error and rate of error change occurring in load disturbance. The robust control of DC servo motor using neural network controller is demonstrated by computer simulation.

Green and Smart Technology with Sensor Applications

This paper reviews the trends of income inequality in Korea from 2000 to 2011. The income inequality in Korea has increased consistently until 2009, and somewhat decreased in 2010. There are reasons to believe that this decrease is more likely to be temporary rather than structural. The decrease in income inequality in 2010 is due to expanded social welfare benefits, such as transfer income to the poor. In order to improve overall economic status and reduce income inequality, policy efforts should be exerted to create more stable employment opportunities with better compensation. Also called for is more active policy intervention to increase the transfer payment. The nature of tax policy is also important. Despite the government’s claim that the recent tax cuts are not for the rich, to the extent that the tax cuts are implemented in favor of the rich, the income inequality will continue to persist.

The Design of Sliding Mode Controller with Nonlinear Sliding Surfaces

Abstract This study develops a variable structure controller using the time-varying nonlinear sliding surface instead of the fixed sliding surface, which has been the robustness against parameter variations and extraneous disturbance during the reaching phase. By appling TS algorithm to the regulation of the rionlinear sliding surface, the reaching time of the system trajectory is faster than the fixed method. This proposed scheme has better performance than the conventional method in reaching time, parameter variation and extraneous disturbance. The effectiveness of the proposed control scheme is verified by simulation results. Key Words : Plants of Auto-equipment Systems, Robustness Control, Variable structure control, Neural Network Sliding mode, Nonlinear systems 이 논문은 2009년도 청운대학교 교내학술연구비 지원에 의해 연구되었음 . * 교신저자: 조현섭(chohs@chungwoon.ac.kr)접수일 09년 11월 10일 수정일 09년 12월 09일 게재확정일 09년 12월 16일 1. 서론 기존 설비시스템의 적응제어 기법은 동적 시스템의 수학적 모형을 필요로 하며, 동적 시스템은 비선형성을 가지고 있으며, 비선형 특성이 심한 시스템의 제어는 아주 어렵다. 실제로 동적시스템의 모형은 비선형성, 불확정성, 시간지연, 시변 시스템의 변수, 구조등에 의해서 정확하게 기술한다는 것은 불가능하다. 가변 구조 제어방식은 비선형 시스템에 대하여 안정성을 보장할 수 있고, 외란이나 잡음에 대하여도 매우 강인함은 일반적으로 잘 알려진 사실이다[1,2]. 하지만 시스템의 불확실성을 보상하며, 스위칭 평면상에서 시스템이 동작하기 위해서는 제어 입력 값의 급격한 변화가 요구된다. 이러한 급격한 입력 값의 변화는 스위칭 평면상에서 떨림 현상을 유발하게 되어 시스템의 모델링에서 미처 고려하지 않았던 고주파 성분이 문제가 되기도 한다. 이 떨림 현상을 제거하기 위해서 스위칭면을 엄격하게 고정시키는 것이 아니라 적당히 경계층을 도입하여, 경계층 영역 내에서 제어 입력 값을 연속적으로 근사화 시켜 사용했다[3]. 근래에, 퍼지이론을 이용한 제어가 여러 부분에서 시도되고 있고, 가변 구조 제어방식에도 퍼지 이론이 접목되었다[4,5]. 이는 경계층을 여러 개로 분할하여 소속 함수를 할당함으로써 오차와 오차 변화율의 크기에 따라 퍼지 추론이 수행된다. 이와 같이 스위칭 면을 엄격하게 고정시키는 것이 아니라 경계층을 도입함으로써 떨림 현상을 완화시키는 반면에 오차의 크기는 증가하였다. 또한 최근에 입․출력 관

Direct-Sequence Spread-Spectrum Systems for Interference Signal Control

In this paper, we propose a frequency-domain interference cancellation algorithm for direct-sequence spread spectrum systems. In the previously proposed frequency-domain interference cancellation algorithms that protocol defines the rules concerning the collection of means of Transmission Control Protocol (TCP: Transmission Control Protocol) is the most widely used in the transport layer. Two-way traffic through the network path to the same end-to-end transfer of data in the opposite direction between pairs of nodes are infused with two or more TCP connection using the network traffic patterns from the exchanger and routers share results of approval. Per-flow input/output structure of matter using the LTS online reaction when evaluated as this is the most important factor. TCP-MT when the connection duration is one of the largest performance gains.

An Effect of Korean Wave on Domestic Cosmetics Industry of Korea Boryeong Mud

Korean wave is intangible cultural product for foreigners visiting Korea and continuous development of Korean wave products are required to foreign accepters who want new stimulation. This study started because of the intention to examine the process cosmetics industry accepted cultural phenomenon of Korean wave positively, reinterpreted it industrially and settled in overseas field successfully as well as diagnose the directivity. Through the effects Korean wave makes on cosmetics industry and actual examples of embodiment, we can realize that Korean wave model shows influences as one axis of brand expansion and cultivates brand property. Cosmetics industry shows that the process that industry is introduced without any effort in the place where culture was introduced successfully at the front.

A Study on the Fabrication and Characteristics of Ceramic Heater Apparatus with High Efficiency

Compositional design and optimization of processing parameters are key factors for controlling and improving the properties of electroconductive ceramic composites. Temperature rising time of sheath heater is 1.1 times faster than SiC ceramic heater. Heating insulation of SiC ceramic heater is 2.7 times larger than sheath heater. If SiC ceramic heater is one body type of a product application, contact resistance will decrease. I think that temperature initial rising time is faster than now. The more SiC ceramic heater is used for a long time, the more economic benefit is larger in the view point of heat insulation.

Real-Time Collision-Free Trajectory Control of Nonlinear Dynamic Manipulator Control Using DNP Controller

Abstract This study develops a variable structure controller using nonlinear surface instead of the fixed, which has been the robustness against parameter variations and extraneous disturbance during the reaching phase. reaching time of the system trajectory is faster than the fixed method. This proposed scheme has better performance than the conventional method in reaching time, parameter variation and extraneous disturbance. The effectiveness of the proposed control scheme is verified by simulation results. Key Words : Dynamic Neural Processor, Association, Plants of Auto-Equipment Systems, Robustness Control, Nonlinear Systems * 교신저자: 조현섭(chohs@chungwoon.ac.kr)접수일 09년 12월 22일 수정일 10년 02월 17일 게재확정일 10년 03월 18일 1. 서론 신경망 분야의 발전으로 인해 자동화 시스템의 제어에 새로운 방향이 제시되고 있으며 신경망은 함수 사상과 동적 반복 능력이라는 장점에 의해 좌표 변환 학습에 사용될 수 있다[1-3]. 본 논문에서 논의된 신경망 구조는 임의 신경활동이 여기와 금지의 신경 생리학적인 근거에 기초하여 개발된 dynamic neural processor (DNP)이다. 또한 신경 집단의 최소 위상은 여기(양성), 금지(음성), 여기-금지(여기에서 금지로의 시냅스 연결), 금지-여기(금지에서 여기로의 시냅스 연결)궤환 루프를 포함한다. 신경 집단의 가장 중요한 속성의 하나는 비선형 시스템 해석의 관점에서 기술할 수 있는 몇 가지 기본적인 속성이다. 예를 들어 이들 패턴은 작업 공간 좌표와 모형 다리의 대응하는 관절각을 나타낼 수 있다. 이들 두 패턴 집합의 연상은 기본적으로 자동화 시스템의 로봇 계열에서는 역기구학적으로 계산된다. 이러한 전제를 바탕으로 자동화 시스템에서 매니퓰레이터 제어 문제의 응용에 DNP를 제안하였다. 따라서 DNP의 구조에 대해 설명하고 신경망의 적응적인 가중치에 대한 학습 알고리듬을 제시한다. 제안된 제어 기법의 효과는 시뮬레이션에 의하여 확인하였다.

Uncertainty-Compensating Neural Network Control for Nonlinear Systems

Abstract In this paper, a direct controller for nonlinear plants using a neural network is presented. The composed of the control input by using RBF neural networks and auxiliary input to compensate for effects of the approximation errors and disturbances. In the results, using this scheme, the output tracking error between the plant and the reference model can asymptotically converge to zero in the presence of bounded disturbances and approximation errors. Simulation results show that it is very effective and can realize a satisfactory control of the nonlinear system. 요 약 본 논문은 비선형 동적 신경망을 이용하여 직접 제어에 관한 연구이다. RBF 신경망을 이용한 제어입력과 근사화 오차 및 외란의 영향을 제거하기 위한 보조제어 입력으로 구성하였다 . 외란이나 근사화 오차에 관계없이 플랜트와 기준모델 사이의 오차가 0이 되도록 하는 알고리즘을 구할 수 있었다. 시뮬레이션 결과는 매우 효과적이며 비선형 시스템의 만족스러운 학습 성능을 증명하였다. Key Words : Nonlinear systems, Robustness Control, Plants of Auto-equipment Systems, Dynamic NeuralProcessor, Robustness Control * Corresponding Author : Hyun-Seob Cho(chohs@chungwoon.ac.kr)Received December 31, 2009 Revised February 26, 2010 Accepted May 13, 2010

A Study on Analysis Characteristic Self-similar for Network Traffic with Multiple Time Scale

In this paper, self-similar characteristics over statistical approaches and real-time Ethernet network traffic measurements are estimated. It is also shown that the self-similar traffic reflects real Ethernet traffic chareacteristics by comparing TCP-MT source model which is exactly self-similar model to the traditional Poisson model.

A Study on The Optimal Design of SiC Ceramic Heater

Compositional design and optimization of processing parameters are key factors for controlling and improving the properties of SiC-based electroconductive ceramic composites. Temperature rising time of sheath heater is 1.1 times faster than SiC ceramic heater. Heating insulation of SiC ceramic heater is 2.7 times larger than sheath heater. If SiC ceramic heater is one body type of a product application, contact resistance will decrease. I think that temperature initial rising time is faster than now. The more SiC ceramic heater is used for a long time, the more economic benefit is larger in the view point of heat insulation.