• Journal of Institute of Control, Robotics and Systems
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• v.6 no.12
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• pp.1093-1098
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• 2000

This paper presents an efficient algorithm for including the kinematic calibration data into the motion controller to improve the positioning accuracy of the manipulators. Rather than spending several iterations for finding the inverse solution of the calibrated kinematics, our approach requires only the nominal inverse solution and the calibrated forward kinematics for providing a better position command promptly. Thus, real-time application is guaranteed whenever the manipulators nominal inverse solution can be expressed in a closed form. Experimental results show that the line tracking performances can be remarkably improved by employing our algorithm.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2005.05a
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• pp.9-13
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• 2005

A comprehension-based computational model of pilot action planning called ADAPT is presented to model pilot performance in a flight simulation context. Individual pilots were asked to execute a series of flight maneuvers using a flight simulator, and their eye-scanning, control movements, and flight performance were recorded in a time-synched database. Computational models of each of the 25 individual pilots were constructed, and the individual models simulated execution of the same flight maneuvers performed by human pilots. The time-synched eye-scanning, control movements, and flight performance of individual pilots and their respective models were compared to test ADAPT's predictive validity.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.155-158
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• 2000

A new control method for single-phase shunt active power line conditioners(APLC's) operated under zero average power consumption is proposed in this paper. The amplitude of the sinusoidal source current which is in-phase with the source voltage can be determined from the average value of the instantaneous load power. Then the command current for the shunt APLC is obtained by subtraction the source current from the load current. Neither bulky filter nor time-consuming computation is required. The shunt power compensator supplies all the harmonics of he load current and the source only supplies the fundamental component,. Experimental results on a prototype verify the feasibility of the presented scheme,

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.461-466
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• 2005

This paper presents a new speed control scheme of the spindle induction motor (IM) using fuzzy-logic control in fold weakening region. The implementation of the proposed FLC-based spindle IM are investigated and compared to those obtained from the conventional PI controller based drive system, we have confirmed good simulation and experimental results at different dynamic operating conditions such as sudden change in command speed, step change, etc.

• Journal of Mechanical Science and Technology
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• v.17 no.11
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• pp.1693-1703
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• 2003

This paper presents a new local obstacle avoidance method for indoor mobile robots. The method uses a new directional approach called the Lane Method. The Lane Method is combined with a velocity space method i.e., the Curvature-Velocity Method to form the Lane-Curvature Method (LCM). The Lane Method divides the work area into lanes, and then chooses the best lane to follow to optimize travel along a desired goal heading. A local heading is then calculated for entering and following the best lane, and CVM uses this local heading to determine the optimal translational and rotational velocities, considering some physical limitations and environmental constraint. By combining both the directional and velocity space methods, LCM yields safe collision-free motion as well as smooth motion taking the physical limitations of the robot motion into account.

• Journal of Advanced Navigation Technology
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• v.3 no.2
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• pp.120-131
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• 1999

For the phase measurement in the radar system using the magnetron pulse source, the STALO (Stable Local Oscillator) frequency need to be controlled to provide the stable intermediate frequency. In radar receiver, AFC(Automatic Frequency Control) circuit detects the transmitting frequency change and controls the STALO frequency to keep the intermediate frequency stable. In this paper, we designed and implimented AFC circuits for radar receiver. The frequency deviation is detected and compared with the reference frequency and the STALO frequency is controlled by the digital command signal.

• Journal of Communications and Networks
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• v.10 no.3
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• pp.308-315
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• 2008

When operating in frequency-division duplex (FDD) mode, transmit beamforming in multiple-input single-output (MISO) wireless communication systems typically requires accurate knowledge of downlink channel state information (CSI) at the transmitter. In practical FDD systems, obtaining such downlink CSI at the transmitter is challenging, if not impractical. To circumvent such challenge and support user mobility, we present a new method for transmit beamforming based on simple beam-control commands (BCCs) in MISO FDD mobile systems. We then numerically evaluate the effects of BCC errors in terms of transmit power efficiency, system capacity, and outage probability.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1978-1982
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• 2005

In this paper, a linear controller is designed for the longitudinal model of X-33 in TAEM (The Terminal Area Energy Management) phase. The CRA (Characteristic Ratio Assignment) is used as the continuous time design method such that the output response of X-33 control system tracks the reference command. The performance of the proposed controller is evaluated through the step response. Also simulation results show that the initial state of the plant is dominantly affected by the poles and zeros of the plant.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1853-1857
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• 2005

In most of motor-driven motion control systems, an encoder is used to measure a position of the motor and the velocity information is obtained by measuring the position increment over a sampling period. The quantization effect due to limited resolution of the encoder induces some measurement errors, and consequently causes deterioration of the motion performance especially in low velocity. In this paper, we propose a gain-scheduled acceleration estimator which works in wider velocity range than the original acceleration estimator. We investigate and analyze characteristics of the velocity measurement mechanism which takes into account the quantization effect of the encoder. Next, we introduce the acceleration estimator and propose a gain-scheduled acceleration estimator. The bandwidth of the gain-scheduled acceleration estimator is automatically adjusted by the velocity command. Finally, its performance is evaluated by simulation and experiment, and the results are compared with those of a conventional method and the original acceleration estimator.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.5
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• pp.153-160
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• 1998

A master-slave system for tele-operation had been developed and tested for several decades. In this paper the master robot is composed of several wires and provides position information of the handle which is driven by a operator within the master robot work space. A PC is used for the command calculation for a slave robot. This paper deals with the relation between the number of strings and D.O.F of the master robot, control method of the slave robot during the operation and the monitoring method over the working area by the computer graphics simulation. The D.O.F of the master robot can be modified by adding or subtracting some strings. The controller of the slave robot uses the advanced PD control method to keep the performance against varying working load.