• 한국지능시스템학회논문지
• /
• 제13권5호
• /
• pp.606-613
• /
• 2003

As a technical method for controlling chaotic dynamics, this paper presents a predictive control for chaotic systems based on radial basis function networks(RBFNs). To control the chaotic systems, we employ an on-line identification unit and a nonlinear feedback controller, where the RBFN identifier is based on a suitable NARMA real-time modeling method and the controller is predictive control scheme. In our design method, the identifier and controller are most conveniently implemented using a gradient-descent procedure that represents a generalization of the least mean square(LMS) algorithm. Also, we introduce a projection matrix to determine the control input, which decreases the control performance function very rapidly. And the effectiveness and feasibility of the proposed control method is demonstrated with application to the continuous-time and discrete-time chaotic nonlinear system.

• 전기학회논문지
• /
• 제62권1호
• /
• pp.95-100
• /
• 2013

This paper presents a new state feedback control approach for communication networks based control systems in which control input and output observation time-delay natures are generally occurred in practice. We first establish a generic state feedback control framework based on well-known linear system theory. A maximum time-delay value which allows critical stability of whole control system are defined to make a positive definite Lyapunov function which is mathematically composed of controlled system states. We analytically derive its control parameters by using a steepest descent optimization method in order to guarantee a stability condition through Lyapunov theory. Computer simulation is numerically carried out for demonstrating reliability of the proposed NCS algorithm and a comparative study is accomplished to prove its superiority for which the traditional control approach for NCS is made use of under same simulation scenarios.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.446-449
• /
• 1997

We propose a control law in discrete time domain of the bilateral feedback teleoperation system using neural network and the reference model type of adaptive control. Different from traditional teleoperation systems, the transmission time delay irregularly changes. The proposed control method controls master and slave systems through identification of master and slave models using neural networks.

• 산업기술연구
• /
• 제22권B호
• /
• pp.251-260
• /
• 2002

In this thesis, a three degrees of freedom robot, which is able to provide sufficient precision for various robot researches, has been developed. The cable mechanism is used as a basic transmission of robot joints. Based on an optimal design strategy, link and joint parameters are determined and then overall geometry of the robot is designed. As an architecture of robot control, real time control system using real time linux and RtiC-Lab(Real Time Controls Laboratory) is developed. This system, written in C and based on Linux O/S, includes text editor, compiler, downloader, and real time plotter running in host computer for developing control purpose. Using these hardware and software, simple PD position control is implemented, the results shows the effectiveness of the system.

• Journal of Electrical Engineering and Technology
• /
• 제2권2호
• /
• pp.152-156
• /
• 2007

This paper proposes a method for real-time control of both capacitors and ULTC in a distribution system to reduce the total power loss and to improve the voltage profile over the course of a day. The multi-stage consists of the off-line stage to determine dispatch schedule based on a load forecast and the on-line stage generates the time and control sequences at each sampling time. It is then determined whether one of the control actions in the control sequence is performed at the present sampling time. The proposed method is presented for a typical radial distribution system with a single ULTC and capacitors.

• International Journal of Contents
• /
• 제13권1호
• /
• pp.22-30
• /
• 2017

The diffusion of advanced mobile technology has introduced new types of personal information or 'location data'. These new data mean new opportunities for businesses, such as location-based services (LBS), but have resulted in new consumer anxieties regarding disclosure of personal information. This study examines the effects of the consumers' perceived control over "time-andplace" information in location-aware services on their perceived privacy risk. A total of 270 respondents participated in this study. Conditions of perceived privacy control were operationalized over time-and-place information, in a $2{\times}2$ factorial design. Results indicate that the perceived control over time-and-place personal information is a significant predictor of perceived risk, and control assurances over time-and-place information enhances the perception of control, thus alleviating the perceived risk. In addition, the effect is much more significant when time and place were combined.

• Smart Structures and Systems
• /
• 제14권6호
• /
• pp.1081-1103
• /
• 2014

Real-time hybrid simulation (RTHS) has emerged as an important tool for testing large and complex structures with a focus on rate-dependent specimen behavior. Due to the real-time constraints, accurate dynamic control of servo-hydraulic actuators is required. These actuators are necessary to realize the desired displacements of the specimen, however they introduce unwanted dynamics into the RTHS loop. Model-based actuator control strategies are based on linearized models of the servo-hydraulic system, where the controller is taken as the model inverse to effectively cancel out the servo-hydraulic dynamics (i.e., model-based feedforward control). An accurate model of a servo-hydraulic system generally contains more poles than zeros, leading to an improper inverse (i.e., more zeros than poles). Rather than introduce additional poles to create a proper inverse controller, the higher order derivatives necessary for implementing the improper inverse can be calculated from available information. The backward-difference method is proposed as an alternative to discretize an improper continuous time model for use as a feedforward controller in RTHS. This method is flexible in that derivatives of any order can be explicitly calculated such that controllers can be developed for models of any order. Using model-based feedforward control with the backward-difference method, accurate actuator control and stable RTHS are demonstrated using a nine-story steel building model implemented with an MR damper.

• Journal of Power Electronics
• /
• 제18권4호
• /
• pp.1075-1085
• /
• 2018

To deal with the operation performance degradation of permanent magnet synchronous machine (PMSM) drives with uncertainties and unmodeled dynamics, this paper presents a finite-time nonlinear disturbance observer (FTNDO) based discretized integral sliding mode (DISM) composite control scheme. Based on the reaching-law approach, a DISM speed controller featuring a superior dynamic quality and global robustness against disturbances is constructed. This controller can avoid the reaching phase and overlarge control action. In addition, a sliding mode differentiator based FTNDO is devised and extended to the discrete-time domain for disturbance estimation. The attractive features of the FTNDO are that it can provide a finite-time converging estimation and alleviate the chattering effect in conventional sliding mode observers, while retaining robustness to parameter variations. By feeding the estimate forward to the pre-stage DISM controller, both disturbances and chattering can be significantly suppressed. Moreover, considering the estimation error of a FTNDO caused by discrete sampling, a stability analysis of the composite controller is discussed. Experimental results validate the superiority of the presented scheme.

• 정보처리학회논문지D
• /
• 제11D권2호
• /
• pp.453-460
• /
• 2004

본 논문에서는 I/O 인터페이스 제어 보드와 ISA 인터페이스 제어 보든 그리고 레고 기반의 프로토타이핑(Prototyping)을 통해 실시간 신발 공정 컨베이어 제어를 위한 원격 감시 및 제어 시스템을 구현하였다. 컨베이어 서버에서 실시간으로 공정을 제어하기 위하여 작업의 우선권을 사용자가 정할 수 있는 RTLinux(Real-Time Linux)를 사용하였으며, RTLinux 기반으로 디바이스 드라이버를 작성하였다. 이를 통해 Client/Server 분산 환경 시스템의 구현 및 테스트를 하며, JMF(Java Media Framework) 기반의 모니터링 시스템을 구현하여 전체 공정 상황을 확인하였다.

• 한국지열·수열에너지학회논문집
• /
• 제12권4호
• /
• pp.21-26
• /
• 2016

In this study, the control strategies of indoor air temperature in floor radiant heating system were researched by computer simulation. The temperature difference based time control method using the difference of indoor set temperature and indoor temperature is compared with the existing On-Off control one for heating control performances. As a result, the temperature difference based time control method shows better thermal environmental characteristics in case of selected operational conditions in comparison with existing control one.