• International Journal of Control, Automation, and Systems
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• 제4권2호
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• pp.172-177
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• 2006

In the networked control system (NCS), the uncertain network-induced delay and nonlinear controlled object are the main problems, because they can degrade the performance of the control system and even destabilize it. In this paper, a class of uncertain and nonlinear networked control systems is discussed and its sufficient condition for the robust asymptotic stability is presented. Further, the maximum network-induced delay that insures the system stability is obtained. The Lyapunov and LMI theorems are employed to investigate the problem. The result of an illustrative example shows that the robust stability analysis is sufficient.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.209-213
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• 1987

This paper presents decentralized discrete-time system which is optimized by hierarchical control for process automation via the extended interaction balance method. This proposed method can control general matrix which input matrix is not block diagonalization. Also, this paper shows convergence condition of proposed method.

• Journal of Power Electronics
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• 제18권4호
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• pp.1190-1200
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• 2018

A current sourced bi-directional wireless power transfer (WPT) system is proposed to solve the problems that exist in the bi-directional WPT for vehicle-to-grid (V2G) systems. These problems include the fact that these systems are not safe enough, the output power is limited and the control methods are complicated. Firstly, the proposed system adopts two different compensation and control methods on both the primary and secondary sides. Secondly, based on an AC impedance analysis, the working principle is analyzed and the parameter configuration method with frequency stability is given. In order to output a constant voltage, a bi-directional DC/DC circuit and a controllable rectifier bridge are adopted, which are based on the "constant primary current, constant secondary voltage" control strategy. Finally, the effectiveness and feasibility of the proposed methods are verified by experimental results.

• International Journal of Automotive Technology
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• 제8권3호
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• pp.299-308
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• 2007

This study proposes a two-layer hierarchical control system that integrates active front wheel steering and four wheel braking torque control to improve vehicle handling performance and stability. The first layer is a robust model matching controller (R-MMC) based on linear matrix inequalities (LMIs), which optimizes an active front steering angle compensation and a desired yaw moment control, and calculates reference wheel slip for the target wheel according to the desired yaw moment. The second layer is a moving sliding mode controller (MSMC) that can track the reference wheel slip in a predetermined time by commanding proper braking torque on the target wheel to achieve the desired yaw moment. Since vehicle sideslip angle measurement is difficult to achieve in practice, a sliding mode observer (SMO) that requires only vehicle yaw rate as the measured input is also developed in this study. The performance and robustness of the SMO and the integrated control system are demonstrated through comprehensive computer simulations. Simulation results reveal the satisfactory tracking ability of the SMO, and the superior improved vehicle handling performance, stability and robustness of the integrated control vehicle.

• Journal of Power Electronics
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• 제13권5호
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• pp.814-828
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• 2013

The LCL resonant inductive power transfer (IPT) system is increasingly used because of its harmonic filtering capabilities, high efficiency at light load, and unity power factor feature. However, the modeling and controller design of this system become extremely difficult because of parameter uncertainty, high-order property, and switching nonlinear property. This paper proposes a frequency and load uncertainty modeling method for the LCL resonant IPT system. By using the linear fractional transformation method, we detach the uncertain part from the system model. A robust control structure with weighting functions is introduced, and a control method using structured singular values is used to enhance the system performance of perturbation rejection and reference tracking. Analysis of the controller performance is provided. The simulation and experimental results verify the robust control method and analysis results. The control method not only guarantees system stability but also improves performance under perturbation.

• Journal of Power Electronics
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• 제13권5호
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• pp.798-805
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• 2013

This paper presents the control and implementation of the dual-stator-winding induction generator for variable frequency AC (VFAC) generating system. This generator has two sets of stator windings embedded into the stator slots. The power winding produces the VFAC power to feed the loads, and the control winding is connected to the static excitation controller to control the generator for output voltage regulation with speed and load variations. On the basis of the idea of power balance, an instantaneous slip frequency control (ISFC) strategy using the information of both the output voltage and the output power is used in this system. A series of experiments is carried out on a 15 kW prototype for verification. Results show that the system has good static and dynamic performance in a wide speed range, which demonstrates that the ISFC strategy is suitable for this system.

• 한국산학기술학회논문지
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• 제16권1호
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• pp.646-651
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• 2015

본 논문에서는 일반적인 건물자동제어 시스템의 아키텍처를 네트워크 구성과 관제점, 상호운영성, 성능 측면에서 분석하고, 점대점 고속 유선 방식으로 연결된 가상화 기반의 새로운 건물자동제어 시스템을 제시하였다. 클라우드 컴퓨팅 기반의 건물자동제어 시스템은 사용자 기반의 환경제어를 가능하게 하며 건물자동제어 시스템의 성능 향상을 통하여 건물에너지관리를 효율적으로 수행할 수 있다. 또한, 가상화 방식은 부하관리사업자의 건물 군관리를 효율적으로 수행할 수 있도록 한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.572-576
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• 1989

Transducer interfaces computer system with electric system. It is important in electric automation system. The characteristics, sorts, component of transducer is introduced in this paper. Previously, in order to support comprehension of transducer, we explain the necessity of computer system control, system components, the principle of operation.

• 한국실내디자인학회논문집
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• 제16권4호
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• pp.110-118
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• 2007

Technology has been viewed at various stages of civilization as leading to future progress. The building, its services systems and management of the work process all contribute to the well-being of people within an organization. Productivity relies on there being a general sense of high morale and satisfaction with the workplace. Now buildings are considered as providing a milieu for human creativity. Flexibility, adaptability, service integration and high standards of finishes offer an intelligence threshold. Building Automation System(BAS) - controlled lighting systems may offer incremental energy saving. Conventional Lighting control systems often control equipment in a single room or over the limited area, because they are centralized control systems, which means that all the controlled circuits must be wired to a single control panel. The computers used by these systems are typically dedicated microprocess that perform only lighting control functions. By comparison, modern Building automation systems are distributed control system, which means that their computing hardware and software are distributed as a network that microprocessor-based control modules and standard PC. PLC(Programmable Logic controller) is extensible virtually without limits, so that all the lighting in a facility can be controlled by single, unified system - the same system that also can control and monitor the building's HVAC, security, and manufacturing processed, elevators, and more. A Building automation system can control light using schedules, manual controls, occupancy sensors, and photosensors, either singly or in combination. Building Lighting control and monitoring system will be for a energy saving and efficient building management system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1672-1675
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• 2003

In this study, we developed full automation test system for pressure vessel. This pressure vessel containing oxygen, nitrogen and carbon is widely used in industrial field. The test items of pressure vessel are divided into three branches which is weight measurement, water-hydraulic, and leakage test. After leakage test is completed, cleaning and dry progress is carried out. And control system is consist of three controller which is PLC, monitoring system and database system. PLC is control all of system. Monitoring system measures weight, pressure, flow etc and display to all conditions. Database system stores tested data. we design system to control all test modules in communication by a second period with three control modules. Finally, we verified this system by field test.