• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.546-551
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• 1993

A new robust sliding mode controller is formulated for the tip position control of a single-link flexible manipulator with parameter variations. After establishing the plant model characterized by a noncollocated uncertain control system, a sliding surface which guarantees stable sliding mode motion is synthesized in an optimal manner. The surface is then modified to adapt arbitrarily given initial conditions. A discontinuous control law associated with the modified surface is designed by restricting that velocity state variables are not available from direct sensor measurements. Using the proposed control law favorable system responses are accomplished through shortening the reaching phase of state trajectory without increasing maximum control torque as well as undesirable chattering. Furthermore, a low sensitiveness to uncertainties is obtained from inherent salient properties of the proposed control system. Computer simulations are undertaken in order to demonstrate these superior control performance characteristics to be accrued from the proposed methodology.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.2
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• pp.269-275
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• 1990

Nonaxisymmetric bifurcation behaviours of composite tubes two different materials subjected to uniform radial shrinkage at the external surface have been investigated and compared with those of single tube. The effect of material parameters normalized with respect to those of outer tube upon the bifurcation point and corresponding mode has been clarified. The parameters substantially affect the bifurcation mode with long-wavelength so that the composite tube with low hardening exponent or with high yield stress of inner tube destabilizes the overall deformation of the tube. However surface type bifurcation, short-wavelength mode, shown on the traction-free inner surface is hardly affected by the material parameters. The surface type bifurcation completely depends on the material characteristics of inner tube and the bifurcation point of composite tube almost coincides with the of single tube.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.233-236
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• 2004

In this paper, a new sensorless vibration control scheme is proposed for a flexible manipulator system. A robust sliding mode controller incorporating with a ‘reaction moment observer’ used for the estimation of the reaction moment reciprocally acting on flexible arm and hub inertia is introduced to achieve desired control target. The rigid body dynamics of the single-link flexible manipulator is simply considered in the design of the sliding mode controller. Then, the reaction moment is estimated by the proposed reaction moment observer to suppress the residual vibration of the flexible arm. The performance of the proposed control scheme is verified by computer simulation and experiment.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.8
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• pp.407-414
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• 2000

This paper addresses the analysis and design of fuzzy control systems for a class of complex uncertain single-input single-output nonlinear systems. The proposed method represents the nonlinear system using a Takagi-Cugeno fuzzy model and construct a global fuzzy logic controller by blending all local state feedback controllers with a sliding mode controller. Unlike the commonly used parallel distributed compensation technique, we can design a global stable fuzzy controller without finding a common Lyapunov function for all local control systems, and can obtain good tracking performance by using sliding mode control theory. Furthermore, stability analysis is carried out not for the fuzzy model but for the real nonlinear system with uncertainties. Duffing forced oscillation sysmte is used as an example to show the effectiveness and feasibility of the proposed method.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.233-236
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• 2002

We consider a single-input-single-output nonlinear system which can be represented in a normal form. The nonlinear system has a modeling uncertainties including the input coefficient uncertainties. A high-gain observer is used to estimate the states variables to reject a modeling uncertainty. A globally bounded output feedback integral sliding mode control is proposed to stabilize the closed loop system. The proposed integral sliding mode control can asymptotically stabilize the closed loop system in the it presence of input coefficient uncertainty.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.2
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• pp.610-628
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• 2012

Dual carrier frequency offsets (CFOs) occur in multiple-input single-output (MISO)-mode DVB-T2 systems, where signals are transmitted simultaneously from two distributed transmitters in a single frequency network (SFN). In this paper, we first derive an optimal compensation frequency for dual CFOs. We also propose an algorithm that optimizes the compensation frequency for the MISO-mode DVB-T2 application. Its performance is compared with the conventional scheme by using a full DVB-T2 simulator.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.697-700
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• 2005

An adaptive fuzzy sliding-mode controller (SMC) for uncertain or ill-defined single-input single-output (SISO) nonaffine nonlinear systems is proposed. By using the universal approximation property of the fuzzy logic system (FLS), it is tuned on-line to cancel the unknown system nonlinearity. We adopt a self-structuring FLS to guarantee global stability of the closed-loop system rather than semi=global boundedness. The control and adaptive laws are derived so that the estimated fuzzy parameters are bounded and the sliding condition is satisfied.

• ETRI Journal
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• v.34 no.3
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• pp.474-477
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• 2012

The MPEG-D unified speech and audio coding (USAC) standardization process was initiated by MPEG to develop an audio codec that is able to provide consistent quality for mixed speech and music contents. The current USAC reference model structure consists of frequency domain (FD) and linear prediction domain (LPD) core modules and is controlled using a signal classifier tool. In this letter, we propose an LPD single-mode USAC structure using an adaptive widowing-based transform-coded excitation module. We tested our system using official test items for all mono-evaluation modes. The results of the experiment show that the objective and subjective performances of the proposed single-mode USAC system are better than those of the FD/LPD dual-mode USAC system.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.12
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• pp.1222-1229
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• 2007

In this paper, we propose a new obstacle negotiation method for the rescue robot. The rescue robot has a variable geometry single-tracked mechanism, so it can maximize a contact length with ground for the adaptability to off-road and pursue a stable system due to the lower center of gravity. In this research, we add the basis of autonomous navigation, driving mode control based on obstacle detection, to the robot to realize automation of mode transformation. Obstacle detection using PSD(Position Sensitive Device) infrared sensors gives active transformation of the track shape. Finally, experimental results about mentioned are presented.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.949-952
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• 2000

A low power 10bit current-mode folding and interpolating CMOS analog to digital converter (ADC) with arithmetic folding blocks is presented in this paper. A current-mode two-level folding amplifier with a high folding rate (FR) is designed not only to prevent ADC from increasing a FR excessively, but also to perform a high resolution at a single power supply of 3.3V The proposed ADC is implemented by a 0.6${\mu}$m n-well CMOS single poly/double metal process. The simulation result shows a differential nonlinearity (DNL) of ${\pm}$0.5LSB, an integral nonlinearity (INL) of ${\pm}$1.0LSB