• Proceedings of the KSME Conference
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• 2000.11a
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• pp.584-589
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• 2000

When the liquid tanks only partially filled and under translational acceleration, large quantities of liquid move uncontrollably inside the tanks and generate the liquid sloshing effect. Liquid sloshing effect could be a severe problem in launch vehicle stability and control if the liquid modes of motion couple significantly with the launch vehicle's normal modes of motion. Several methods have been employed to reduce the effect of sloshing, such as introducing baffles inside the tanks or dividing a large tank into a number of smaller ones. These techniques, although helpful in some cases, do not succeed in canceling the sloshing effects. In this paper, An attitude controller is designed for a launch vehicle with liquid sloshing effect. Both PD controller and sloshing filter are designed for the objective. PD gains and design parameters are determined by optimal algorithm. The performance of the attitude controller is evaluated via computer simulations.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.165-172
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• 1999

Crane operation for transporting heavy loads causes swinging motion at the loads. This sway causes the suspension ropes to leave their grooves and leads to possibility of serious damages. Generally crane is operated by expert's knowledge. Therefore, a satisfactory control method to supress object sway during transport is indispensible. The dynamic behavior of the crane shows nonlinear characteristics. when the length of the rope is changed the crane is time varying system and the design of anti-sway controller is very difficult. In this paper, the nonlinear dynamic model for the industrial overhead crane is derived. and the feedback gain matrix based on the pole-placement method is proposed to supress the swing motion and control the position of the crane. The performance of the controller for the crane model is simulated on the personal computer.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.9
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• pp.2399-2411
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• 1995

Crane operation for transporting heavy loads inherently causes swinging motion at the loads due to crane's acceleration or deceleration. This motion not only lowers the handling safety but also slows down the handling process. To complement such a problem, Korea Atomic Energy Research Institute(KAERI) has designed several anti-swing controllers using open loop and closed loop approaches. They are namely a pre-programmed feedback controller and a fuzzy controller. These controllers are implemented on a 1-ton crane system at KAERI and their control performances are compared. Test operations show that the new controllers are superior to that of conventional cranes in terms of robustness to the disturbances and adaptation capability to the change of rope length.

• Journal of Navigation and Port Research
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• v.31 no.7
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• pp.597-603
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• 2007

A predictive controller can solve a control problem related to a disturbance-dominant system such as roll stabilization of a ship in waves. In this paper, a predictive controller is developed for a fin stabilizer. Future wave-induced moment is modeled simply using two typical regular wave components for which six parameters are identified by the recursive Fourier transform and the least squares method using the past time series of the roll motion. After predicting the future wave-induced moment, optimal control theory is applied to discover the most effective command fin angle that will stabilize the roll motion. In the results, wave prediction performance is investigated, and the effectiveness of the predictive controller is compared to a conventional PD controller.

• Journal of Power System Engineering
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• v.17 no.3
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• pp.82-88
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• 2013

For commercialized servo drives of the motion stage to include embedded controller, external terminal is provided for tracking command and encoder output, but internal terminal is not for control input. Thus, it is difficult to combine out signal of embedded controller with that of external compensator such as disturbance observer. In this study, for precise tracking control of motion stage without hardware change of the servo drive, tacking control system is composed of an inner loop of servo drive and an outer loop of disturbance observer. Then, the control system is designed so that the output response of actual plant corresponds with nominal model's in transient state as well as in steady state. Finally, the experiment results show that the designed control system is effective to reconcile actual plant behavior with nominal model under nonlinear friction and parameter perturbation.

• Journal of Electrical Engineering and Technology
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• v.10 no.6
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• pp.2420-2426
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• 2015

This paper proposes an evolutionary optimization approach for optimal hopping of humanoid robots. In the proposed approach, the hopping trajectory is generated by a central pattern generator (CPG). The CPG is one of the biologically inspired approaches, and it generates rhythmic signals by using neural oscillators. During the hopping motion, the disturbance caused by the ground reaction forces is compensated for by utilizing the sensory feedback in the CPG. Posture control is essential for a stable hopping motion. A posture controller is utilized to maintain the balance of the humanoid robot while hopping. In addition, a compliance controller using a virtual spring-damper model is applied for stable landing. For optimal hopping, the optimization of the hopping motion is formulated as a minimization problem with equality constraints. To solve this problem, two-phase evolutionary programming is employed. The proposed approach is verified through computer simulations using a simulated model of the small-sized humanoid robot platform DARwIn-OP.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.594-596
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• 2006

In this thesis, we propose a algorithm that is able to detect a user's motion. A minute noise of accelerometer arises cumulative error in case of converting velocity and distance, which makes it difficult to detect movement of sensor. We use a lowpass filter, ALS algorithm, and motion detection block to minimize such cumulative error. we experiment using a motion-detective module which is composed of accelerometer, micro-controller, and serial interface. Our scheme is capable of detecting such as up, down, left, right, forward, and backward movement of the module. It is expected that our scheme is applied to a game controller or user interface of a next generation PC.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.703-707
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• 2000

This paper studied on the lateral motion of the gantry crane which is used for the automated container terminal. Though several problems are occurred in driving of gantry crane, they are solved by the motion by the operator. But, if the gantry crane is unmanned, it is automatically controlled without any human operation. Especially, the collision between wheel-flange and rail is a very critical problem in driving of unmanned gantry crane. To bring a solution to these problems, the lateral and yaw dynamic equations of the driving mechanism of gantry crane are derived. And this study used PD(Proportional-Derivative) Controller to control the lateral displacement and the yaw angle. The simulation result of the driving mechanism using the Runge-Kutta method is presented in this paper.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1322-1326
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• 1990

In this paper, compliant motion control of a manipualator in manipulator is proposed by using the self-tuning adaptive controller. Compliant motion is needed in order to applicated to complicated and accurate fields such as assembly operation in which several parts are matched. For a control method of compliant motion hybrid control is used so forces and position control are proposed selectively through a closed feedback loop. By contacting with environment, the uncertainties higher. Self-tuning controller which adapts to variable dynamic response is applied to compliant motion control in order to satisfy the desired operation. The applicability of the suggested algorithm was confirmed by simulation of the contour tracking task of four joint manipulator.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.514-517
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• 1990

In this paper, compliant motion control of a manipualator in manipulator is proposed by using the self-tuning adaptive controller. Compliant motion is needed in order to applicated to complicated and accurate fields such as assembly operation in which several parts are matched. For a control method of compliant motion hybrid control is used so forces and position control are proposed selectively through a closed feedback loop. By contacting with environment, the uncertainties higher. Self-tuning controller which adapts to variable dynamic response is applied to compliant motion control in order to satisfy the desired operation. The applicability of the suggested algorithm was confined by simulation of the contour tracking task of four joint manipulator.