• Proceedings of the KIEE Conference
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• 2000.11d
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• pp.629-632
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• 2000

Nonlinear frictions which generate many problems in control system exist in almost all the servor control systems. In this paper, the design procedure which employs $H_\infty$ integral controller including two integrators with performance weight is proposed to improve performance of the control system. Limit cycles are unavoidable by the effect of interaction between two integrators and coulomb friction in these system. The describing function method is used to check the limit cycles and determine the coefficients of performance weights to minimize the effect of the limit cycles.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.951-953
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• 1999

In the distributed control systems where the control components, controllers and sensors are distributed on a communications network, there exist network time delays on communication lines between the system components. This paper deals with the ramp tracking controller design issue for such systems. Time delay terms are converted into the rational terms using Pade approximation method and the system is augmented with two integrators for ramp tracking. For this system, ${\mu}$-controller design method, which enables to meet not only performance requirements but robust stabilities simultaneously, is employed.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.518-520
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• 1999

The practical control problems for the time-delay system is considered. The delay-free characteristics of the Smith Predictor is available only when both the process and it's model are exactly matched. So it does not used widely in practical industrial processes. In this paper, using the 2nd-order plus deadtime model in place of the plant model of the Smith predictor, the proposed controller shows the improved performance in case of the very long time delay. And the range of integral constant of the PI controller is also proposed.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.4
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• pp.422-434
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• 1997

In this paper, a two-stage kinematic optimal design for a 3 degree of-freedom (DOF) excavator subsystem, which consists of boom, arm and bucket, is performed. The objective of the first stage is to find the optimal parameters of the joint-actuating mechanisms which maximize the force-torque transmission ratio between the hydraulic actuator and the rotating joint. The objective of the second stage is to find the optimal link parameters which maximize the isotropic characteristic of the excavator subsystem throughout the workspace. It is illustrated that kinematic/dynamic performances of the kinematically optimized excavator subsystem have improved compared to those of original HE280 excavator, with respect to three performance indices such as maximum load handling capacity, maximum velocity capability, and acceleration capability.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.1
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• pp.41-48
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• 2014

This paper analyzes the Monte Carlo localization (MCL) method, which estimates the pose of an indoor mobile robot. A mobile robot must know where it is to navigate in an indoor environment. The MCL technique is one of the most influential and popular techniques for estimation of robot position and orientation using a particle filter. For the analysis, we perform experiments in an indoor environment with a differential drive robot and ultrasonic range sensor system. The analysis uses MATLAB for implementation of the MCL and investigates the effects of the control parameters on the MCL performance. The control parameters are the uncertainty of the motion model of the mobile robot and the noise level of the measurement model of the range sensor.

• International Journal of Control, Automation, and Systems
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• v.4 no.1
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• pp.105-112
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• 2006

The main function of a reactor protection system is to maintain the reactor core integrity and the reactor coolant system pressure boundary. Generally, the reactor protection system adopts the 2-out-of-m redundant architecture to assure a reliable operation. This paper describes the safety assessment of a digital reactor protection system using the fault tree analysis technique. The fault tree technique can be expressed in terms of combinations of the basic event failures such as the random hardware failures, common cause failures, operator errors, and the fault tolerance mechanisms implemented in the reactor protection system. In this paper, a prediction method of the hardware failure rate is suggested for a digital reactor protection system, and applied to the reactor protection system being developed in Korea to identify design weak points from a safety point of view.

• International Journal of Control, Automation, and Systems
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• v.6 no.1
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• pp.44-53
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• 2008

An interacting multiple model (IMM) estimation algorithm based on the mixing of the predicted state estimates is proposed in this paper for a right continuous jump-linear system model different from the left-continuous system model used to develop the existing IMM algorithm. The difference lies in the modeling of the mode switching time. Performance of the proposed algorithm is compared numerically with that of the existing IMM algorithm for noisy system identification. Based on the numerical analysis, the proposed algorithm is applied to target tracking with a large sampling period for performance comparison with the existing IMM.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.4
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• pp.312-317
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• 1996

This paper proposes a neural network controller with the computed torque method. The neural network is used not to learn the inverse dynamic model but to compensate the uncertainties of robotic manipulators. When training the neural network, we use the signals present in the proposed controller, which is simpler than that proposed by Ishiguro et al., whose teaching signals of the neural network come from the robot model.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.11
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• pp.1011-1016
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• 2013

Patients have the paralysis of their wrists, and can't use of their wrists freely. But their wrists can be recovered by wrist-bending rehabilitation exercise. Professional rehabilitation therapeutists exercise the wrists of patients in hospital. But the wrists of patients have not exercised enough for the rehabilitation, because the therapeutists are much less than patients in number. Therefore, the wrist rehabilitation robot should be developed, and it have to measure the applied force to the patients' wrists for their safety. In this paper, the four-axis force/moment sensor was designed for the wrist rehabilitation robot. As a test results, the interference error of the four-axis force/moment sensor was less than 0.91%. It is thought that the sensor can be used to measure the applied force to the patients' wrists.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.38 no.6
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• pp.38-45
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• 2001

In this paper, numerical stability analysis methodology for the singleton-type linguistic fuzzy control systems is proposed. The proposed stability analysis is not the analytical method but the numerical method using the convex optimization of Quadratic Programming (QP) and Linear Matrix Inequalities (LMI). Finally, the applicability of the suggested methodology is highlighted via simulation results.