• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1816-1819
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• 1997

Using the vision system, robotic tasks in unstructured environments can be accompished, which reduces greatly the cost and steup time for the robotic system to fit to he well-defined and structured working environments. This paper proposes a dynamic control scheme for robot manipulator with eye-in-hand camera configuration. To perfom the tasks defined in the image plane, the camera motion Jacobian (image Jacobian) matrix is used to transform the camera motion to the objection position change. In addition, the dynamic learning controller is designed to improve the tracking performance of robotic system. the proposed control scheme is implemented for tasks of tracking moving objects and shown to outperform the conventional visual servo system in convergence and robustness to parameter uncertainty, disturbances, low sampling rate, etc.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.540-545
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• 2004

This article describes the time delay control of the 3-dimensional motion of the container cranes used in dockside container terminals. The container is suspended by four flexible cables via spreader, and due to the disturbances such as the wind and acceleration of cranes, the container undergoes translational(sway) and rotational position errors. And due to the uncertainty of weight and rotational inertia, accurate position control of container crane is difficult to realize. This paper, based on the analysis of 3-dimensional dynamics of container moving systems, develops time delay control algorithm [1]. The developed control algorithm is shown effective in controlling the container position in the presence of gust and parameter uncertainties.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.249-254
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• 1993

In order to respond to the increasing demands of ultraprecision positioning mechanism in the field of precision engineering, more accurate stages are needed whose positioning uncertainty should be in the unprecedented level of nanometers, while maintaining a long travek range. For this application, most conventional stage mechanisms are found not suitable, so the concept of dual servo, which uses two different servos, is one of the new design and control strategies being extensively investigated these days, This paper presents a fine motion mechanism as a part of research on the dual servo control. The stage is made of a single structure of elastic flexure, whose xy .theta. motions are induced in the form of elastic deformation activated by three piezoelectric actuators. Experimental results show that the translational and rotational motions of the stage can be controlled with resolutions of 5 nm and 0.1 arcsec, respectively.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.1
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• pp.155-169
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• 2001

In this paper, dynamic pressure is mainly generated in the closed chamber of gun when the propellant is fired and has exponential pressure motion. Dynamic pressure calibrator with positive step pressure was designed and manufactured to meet the calibration of piezoelectric high pressure transducers which are mainly used to measure dynamic pressure motion in the test of weapon systems. In addition, the results of Performance test and analysis of system uncertainty are provided.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.538-541
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• 1995

Joint flexibilities and frictional uncertainties are known to be a major cause of performance degration in motion control systems. This paper investigates the modeling and compensation of these undesired effects. A hybrid controller, which consists of a predictive controller and a neural network controller, is designed to overcome these undesired effects. Also learning scheme for friction uncertainies, which don't interfere with feedback controller dynamics, is discussed. Through simulation works with two inetia-torsional spring system having Coulomb friction, the effectiveness of the proposed hybrid controller was tested. The proposed predictive & neural network hybrid controller shows better performance over one when only predictive controller used.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1723-1728
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• 2005

This article describes the fuzzy control of the 3-dimensional motion of the container cranes used in dockside container terminals. The container is suspended by four flexible cables via spreader, and due to the disturbances such as the wind and acceleration of cranes, the container undergoes translational(sway) and rotational position errors. And due to the uncertainty of weight and rotational inertia, accurate position control of container crane is difficult to realize. This paper, based on the analysis of 3-dimensional dynamics of container moving systems, describes the design of the fuzzy controller, which does not require the computation time to optimize the distribution of cable tension. The developed controller is shown effective in controlling the container position in the presence of gust and parameter uncertainties.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.8
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• pp.792-799
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• 2008

Motion estimation is crucial in a remote control for its convenience or accuracy. Time delays, however, can occur in the problem because data communication is required through a network. In this paper, state estimation problem with uncertain time delayed measurements is addressed. In dynamic system with noise, after taking measurements, it often requires some time until that is available in the filter algorithm. Standard filters not considering this time delays cannot be used since the current measurement is related with a past state. These delayed measurements are solved with augmented extended Kalman filter, and the uncertainty of delayed time is also resolved based on an explicit formulation. The proposed method is analyzed and verified by simulations.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.467-467
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• 2000

In this paper, a structural design method of robust motion controllers for high-accuracy positioning systems, which makes it possible to predict the performance of the whole closed-loop system, is proposed. First, a stabilizing control input is designed based on robust internal-loop compensate.(RTC) for the system in the presence of uncertainty and disturbance. Next, using the structural characteristics of the RIC, disturbance attenuation properties and the performance of the closed-loop system determined by the variation of controller gains are analyzed. Through this analysis, in some specific applications, it is shown that if the control gain of RIC is increased by N times, the magnitude of error is reduced to its 1/N. Finally, the proposed method is verified through experiments using a high-accuracy positioning system used in the semiconductor chip mounting devices.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.226-226
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• 2000

This paper presents the control problem for the motion of sphere with robot manipulator. The robot manipulator is controlled to regulate the angle of plate for the sphere to track given trajectories on the plate. The center position of the sphere is measured with machine vision system and the advanced algorithm for center detection is proposed in which the change of shape is considered to solve the problem of image distortion. To cope with the variation of plate material and the structure of sphere (size, mass, etc.), sliding mode control, which has robustness to model uncertainty, is applied to the control of robot manipulator.

• 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.