• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.194-201
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• 1998

The beam rotating actuator has been developed. It can be utilized to improve the data transfer rate for the optical disk systems, Newly developed laser beam rotating actuator is applied to put multi-beam spots on more than one track on the optical disk simultaneously. The beam rotating actuator is made of piezoelectric ceramic bimorph as the form of cantilever, Piezoelectric actuators with high resolution, high stiffness and fast frequency response are widely assembled in micropositioning applications. Therefore, the actuator has above 50Hz natural frequency. Beam array is rotated using the dove prism in the end of beamrotator. The dynamic equation of beam rotating actuator is derived theoretically. The actuator is designed on the ground of this analysis. The performance of the beam rotating actuator is verified as the dynamics frequency performance is measured using the dynamic analyzer and sensor.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.479-482
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• 2004

In this article we consider a single maneuvering target Tracking algorithm in the presence of missing measurements and high clutter environments for multi-sensor target tracking problem. The tracking algorithm is based on the Particle filtering method to predict and update target states. Proposed is the AMM-PF(Auxiliary Multiple Model Particle Filter)[2] method for maneuvering target tracking to improve performance in track estimate and maintenance with a high level of uncertainty. The algorithm we propose is compared to the Extended Kalman Filter(EKF). A simulation study is included.

• The Journal of Korea Robotics Society
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• v.4 no.4
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• pp.265-272
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• 2009

IVarious driving mechanisms to adapt to uneven environment have been developed for many urban search and rescue (USAR) missions. A tracked mechanism has been widely used to maintain the stability of robot's pose and to produce large traction force on uneven terrain in this research area. However, it has a drawback of low energy efficiency due to friction force when rotating. Moreover, single tracked mechanism can be in trouble when the body gets caught with high projections, so the track doesn't contact on the ground. A transformable tracked mechanism is proposed to solve these problems. The mechanism is designed with several articulations surrounded by tracks, used to generate an attack angle when the robot comes near obstacles. The stair climbing ability of proposed robot was analyzed since stairs are one of the most difficult obstacles in USAR mission. Stair climbing process is divided into four separate static analysis phases. Design parameters are optimized according to geometric limitations from the static analysis. The proposed mechanism was produced from optimized design parameters, and demonstrated in artificially constructed uneven environment and the actual stairway.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.85-87
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• 2012

We present a numerical investigation on gaseous (ethylene-air mixture) detonation in the elastoplastical metal tubes to understand the wall effects associated with the developing detonation instability. The acoustic disturbances originating from the rapidly expanding tube walls reach the detonating flame surface, thereby causing flame distortions and total energy losses. The compressible Navier-Stokes equations with equation of state for gas and elasto-plastic deformation field equations for inert tubes are solved simultaneously to understand the complex multi-material interaction in the rapidly expanding gas pipe. In order to track governing variables across the material interface, we use the hybrid particle level-set and ghost fluid methods to precisely estimate the interfacial quantities. Features observed from the deforming (thin) tube show substantially different behavior when a detonation propagates in the rigid (thick) tube with no acoustically responding wall conditions.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.539-542
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• 1996

The forces exerted on an object by the end-effectors of multi-manipulators are decomposed into the motion-inducing force and the internal force. Motion-inducing force effects the motion of an object and internal force can't effect it. The motion of an object can't track exactly the desired motion because of internal force component, therefore internal force component must be considered. In this paper using the resolved acceleration control method and the fact that internal force lies in the null space of jacobian matrix, we construct independently the position, motion-inducing force and internal force controller. Secondly we construct the robust controller to preserve the robustness with respect to the uncertainty of manipulator parameters.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.121.3-121
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• 2001

The movement of a ship is important for DBS(Direct Broadcasting Satellite) Receiving Antenna control algorithm design on shipboard. Especially, turning of ship is essential factor to affect the angle change of azimuth and elevation. Therefore, to track the satellite stably, we need the tracking method considering turning rate of ship. In this paper, we propose an effective satellite tracking algorithm for DBS receiving antenna on shipboard. In the proposed method, when a ship is turned, it selects one of the Multi tracking modes - Normal mode, Low speed mode, Middle speed mode and High speed mode - according as turning rate to be calculated by using Gyro sensor.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.1072-1075
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• 1997

To enhance the effective data transfer rate the multi-beam optical disk drive is presented. The Beam rotating actuator is necessary for putting multi-beam on more than one track. Ray tracing was also executed for real system set-up. The Beam Rotating Actuator is made up of piezoelectric material, high stiffness wire hinge and dove prism. The actuator has about 1kHz natural frequency and suitable and suitable operational range. The dynamic equation for the actuator is derived for the control of real system.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.712-719
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• 2000

This paper presents a new algorithm to analyze a train voltages of multi-trains in auto-transformer-fed AC railway systems, using electrical equivalent change. The train current will be divided into circulation and return currents, and these current values are the same. By evaluating each current independently, the result will be more precise. The train current flows through the all auto-transformer corresponding to track impedance. In analyzing the railway system, the algorithm is based on the K.C.L, K.V.L, superposition and circuit separation method. Multi-train's voltages are determined by calculating the catenary voltage at each train's position and adding up these train's voltage drop. Case studies use a field operational data, show that tile proposed method is easily applied.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.6
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• pp.227-233
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• 2002

A vehicle longitudinal control strategy with guaranteed string stability for vehicle stop-and-go(SG) cruise control is presented in this paper. The SG cruise control systems should be designed such that string stability can be guaranteed in addition to that every vehicle in a string of SG cruise control vehicles must track any bounded acceleration and velocity profile of its preceding vehicle with a bounded spacing and velocity error. An optimal vehicle following control law based on the information of the 1311owing distance (clearance) and its velocity relative to the vehicle ahead (relative velocity) has been used and string stability analysis has been done based on the control law and constant time gap spacing policy, A validated multi-vehicle simulation package has been shown that the string stability analysis using the approximate model of the vehicle servo-loop which includes vehicle powertrain and brake control system dynamics is valid in the design of the SG cruise control law with guaranteed string stability.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.1
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• pp.66-73
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• 2016

An Inertial Measurement Unit (IMU)-based Attitude and Heading Reference System (AHRS) can calculate attitude and heading information with long-term accuracy and stability by combining gyro, accelerometer, and magnetic compass signals. Motivated by this characteristic of the AHRS, this paper presents a Motion-Tracking and Localization (MTL) method for a person or walking robot using multi-AHRSs. Five AHRSs are attached to the two calves, two thighs, and waist of a person/walking robot. Joints, links, and coordinate frames are defined on the body. The outputs of the AHRSs are integrated with link data. In addition, a supporting foot is distinguished from a moving foot. With this information, the locations of the joints on the local coordinate frame are calculated. The experimental results show that the presented MTL method can track the motion of and localize a person/walking robot with long-term accuracy in an infra-less environment.