• International Journal of Control, Automation, and Systems
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• v.6 no.2
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• pp.149-159
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• 2008

This paper considers the problem of adaptive fault-tolerant guaranteed cost controller design via dynamic output feedback for a class of linear time-delay systems against actuator faults. A new variable gain controller is established, whose gains are tuned by the designed adaptive laws. More relaxed sufficient conditions are derived in terms of linear matrix inequalities (LMIs), compared with the corresponding fault-tolerant controller with fixed gains. A real application example about river pollution process is presented to show the effectiveness of the proposed method.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.1
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• pp.71-78
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• 2013

In highly reliable and durable systems, failures due to aging might result in catastrophes. Aging monitoring techniques to prevent catastrophes by predicting such a failure are required. Aging can be monitored by performing a delay test at faster clocks than functional clock in field and checking the current delay state from the test clock frequencies at which the delay test is passed or failed. In this paper, we focus on test clock control scheme for a system-on-chip (SoC) with multiple clock domains. We describe limitations of existing at-speed test clock control methods and present an on-chip faster-than-at-speed test clock control scheme for intra/inter-clock domain test. Experimental results show our simulation results and area analysis. With a simple control scheme, with low area overhead, and without any modification of scan architecture, the proposed method enables faster-than-at-speed test of SoCs with multiple clock domains.

• KIEE International Transaction on Systems and Control
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• v.2D no.2
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• pp.72-77
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• 2002

Delay and noise in networked control systems are inevitable and can degrade system performance or stability This paper propose a compensation method for networked control systems with network-induced delay and noise using LMI(linear matrix inequality)-based H_\infty optimization. The H_\infty optimization methods have adapted to account for both the time delay and noise effects. Some simulations applied to inverted pendulum with networked control show that the proposed method works well.

• Smart Structures and Systems
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• v.15 no.3
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• pp.863-879
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• 2015

This paper experimentally investigates the effectiveness and applicability of the time delay control (TDC) algorithm, which is simple and robust to unknown system dynamics and disturbance, for an active mass damper (AMD) system to mitigate the excessive vibration of a building structure. To this end, the theoretical background including the mathematical formulation of the control system is first described; and then, a thorough experimental study using a shaking table system with a small-scale three-story building structural model is conducted. In the experimental tests, the performance of the proposed control system is examined by comparing its structural responses with those of the uncontrolled system in the free vibration and forced vibration cases. It is clearly verified from the test results that the TDC algorithm embedded AMD system can effectively reduce the structural response of the building structure.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.2
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• pp.151-156
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• 1998

This paper presents an $H_{\infty)$ output feedback controller design method for linear systems with delayed state, delayed control input, and delayed masurement output. Using a Lyapunov functional, the stability for delayed systems is discussed independently of delays. Also, sufficient condition for the existence of $H_{\infty)$ controllers of any order is given in terms of three linear matrix inequalities(LMIs). Based on positive definite solutions of their LMIs, we briefly explain the way to construct $H_{\infty)$ controller, which stabilizes time-delay systems independently of delays and guarantees an $H_{\infty)$norm bound.

• Journal of the Semiconductor & Display Technology
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• v.10 no.2
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• pp.49-56
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• 2011

In recent years, owing to the development of the image processing technology, the research to build control system using a vision sensor is stimulated. However, the time delay must be considered, because it works of time to get the result of an image processing in the system. It can be seen as an obstacle factor to real-time control. In this paper, using the pattern matching technique, the location of two objects is recognized from one image which was acquired by a camera. And it is implemented to a position control system as feedback data. Also, a possibility was shown to overcome a problem of time delay using PID controller. A number of experiments were done to show the validity of this study.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.82.2-82
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• 2001

In this paper, when we design and implement an internet-based teleoperation control, some important points that should be considered (e.g., transmission characteristics, time delay prediction and transmission protocol are inspected and simulated. First, we will investigate data transmission characteristics at the Internet, and build a model for the transmission delay and packet loss through the characteristics of that effect. And then, we inspect how to predict transmission delay, and examine transmission protocols which are proper for the control-oriented Internet protocol. Finally, we apply it to a force-reflective teleoperation control system that consists of a six d.o.f haptic interface and a five d.o.f manipulator via the Internet.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.336-340
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• 1997

This paper is a study about motor technic of motion and feedforward control in order to shape cutting control on the machine tool. The shape error caused by delay of the servo system in the direction of radius at the time of circular cutting is reduced by feedforward control, shape error generated by the position command delay is minimized by using the acceleration/deceleration time constant after the interpolation. The study was verified to optimization of motion control on experiments of a vertical machining center of the machine tool.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.697-702
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• 1997

Control system of electric machine systems is often required to provide the good control performance even in the presence of various variable loads. In this study, time delay control technique is adopted to overcome such variable loads. Also, in this research a new approach of avoiding saturation by varying the reference model for the time delay control based systems subject to the step changes in reference inputs. These schemes are verified by applications to the position controls of the AC servo motor system and the engine throttle actuator.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.87-90
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• 2000

This paper describes a register-controlled symmetrical delay-locked-loop (DLL) using hybrid delay line for use in a high frequency double-data-rate DRAM. The proposed DLL uses a hybrid delay line which can cover two-step delays(coarse/fine delay) by one delay element. The DLL dissipate less power than a conventional dual-loop DLL which use a coarse and a fine delay element and control separately. Additionally, this DLL not only achieves small phase resolution compared to the conventional digital DLL's when it is locked but it also has a great simple delay line compared to a complex dual-loop DLL.