• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.6
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• pp.852-862
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• 2013

This paper proposes a target tracking control method for wheeled mobile robots with nonholonomic constraints by using a backstepping-like feedback linearization. For the target tracking, we apply a vision system to mobile robots to obtain the relative posture information between the mobile robot and the target. The robots do not use the sensors to obtain the velocity information in this paper and therefore assumed the unknown velocities of both mobile robot and target. Instead, the proposed method uses only the maximum velocity information of the mobile robot and target. First, the pseudo command for the forward linear velocity and the heading direction angle are designed based on the kinematics by using the obtained image information. Then, the actual control inputs are designed to make the actual forward linear velocity and the heading direction angle follow the pseudo commands. Through simulations and experiments for the mobile robot we have confirmed that the proposed control method is able to track target even when the velocity sensors are not used at all.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.4
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• pp.170-179
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• 2004

The paper presents technical issues which integrated sensors must address to be implemented in the next generation of power electronics and motor drives. The underlying goal of the sensor integration will be to improve reliability of power conversion systems while making the power converter and motor drive become the primary source of diagnostic signals for the application. The paper focuses on design methodologies that will allow this integration to succeed in meeting the technical demands for both reliability and for application level diagnostics.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.9
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• pp.928-933
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• 1990

In the vector controlled induction machine drives, mechanical speed sensors such as shaft encoder and resolver have been used. However, the mechanical speed sensors present some problems and restrict the wide applications of high performance AC drives. This paper describes the vector strategy with the speed estimation algorithm in which motor slip frequency is calculated. Also, the angle deviation of the rotor flux vector is calculated and instantaneously compensated to keep the q axis flux zero in the rotational reference frame.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.314-316
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• 2000

Urea is detected as an indicator of renal disease in the human body. For these reasons, many biosensors for urea have been developed based on the enzymatic reaction of urea hydrolysis catalyzed by urease. Potentiometric method is applied reversible reaction system. But urea hydrolysis reaction may not has a reversible reaction mechanism in electrode surface. Therefore we applied to voltammtricmethod to obtain a sensitivity curve. The sensitivity of sensors was 34 ${\mu}$A/decade.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.7
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• pp.940-945
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• 2018

In this study, we make a study on a system to determine a person's sitting posture by measuring the distribution of pressure in the floor of a chair or in a cushion using pressure sensors. If the wrong sitting posture is detected, a warning message is given through the vibration motor in real time to correct the imbalance of the wrong habits and posture, and prevent Bulging disc or Herniated disc.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04c
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• pp.119-120
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• 2008

In this paper, viologen derivative is used as charge transfer material to develop sensors for detecting the organic pollutants which are the main reason of harbor pollution. We fabricated self-assembled monolayers of viologen derivative on gold electrode of QCM and investigated an electrochemical behavior property. We also determined electrochemical sensing property about environmental pollution materials such as bezene, phosphate and surfactant through quantitative and qualitative analysis of charge transfer using intrinsic property of viologen derivative by temperature and concentration change. From the achieved results, we can apply and develope the detecting sensors for harbor pollutants.

• Transactions on Electrical and Electronic Materials
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• v.15 no.3
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• pp.136-138
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• 2014

In this study, cholesterol sensors consisting of a mixture of cholesterol oxidase (ChOx) and zinc oxide (ZnO) nanoparticles (NPs) are constructed on plastic substrates and their sensing characteristics are examined in air. The current of the ChOx-ZnO NP film decreases in magnitude as cholesterol molecules are adsorbed on the film, due to the resulting increase in the number of electrons generated by the reaction between the cholesterol and the ChOx. The cholesterol sensor shows a high sensitivity of $1.08{\mu}A/mM$ and a wide detection range from 10 nM to 1 mM.

• Journal of Power Electronics
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• v.11 no.4
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• pp.424-429
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• 2011

In this paper, the simulator of an on-line monitoring system for the range extender electric vehicle has been developed. The messages from the four control modules, the air pressure and fuel level sensors data, and the on/off switching states of 31 indicator lamps can be received through the control area network (CAN), and displayed on the graphic panel. The simulator was designed using the four DSP boards, variable resistors, and toggle switches instead of the four control modules, sensors, and switching state of indicator lamps on an actual series hybrid electric vehicle (SHEV) bus, respectively. The performance of the monitoring technologies was verified with the simulator at the laboratory, and then it was tested on an actual SHEV bus. The simulator is very useful at the initial development of the monitoring system at the hybrid-type or electrical vehicles.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2167-2169
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• 2003

The LQG regulator presented in this dissertation is designed to improve system stability with the structure in which Kalman Filters and LQ regulator are inter-connected to avoid disturbances on the system. For the sake of performance evaluation of the LQG regulator in this dissertation, the regulator is put in use for the speed control of DC Servo Motors without speed sensors on them to realize speed control without sensors by estimating uncertain speed with its state signals and to construct an optimal controller using the LQG regulator. Furthermore, state estimation process with white noise entered onto the systems is been experimented through a series of simulation. As a consequence, the process of estimating speed signals out of the signals with white noise inputs is confirmed using Kalman Filter.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.11
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• pp.1639-1644
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• 2015

Auxiliary air compressor(ACM) applied to railroad cars is a device which controls amount of compressed air in order that pantographs can be mounted correctly on the roof of an electric train. Existing ACMs consist of dc motors and brushes wear out due to friction with a commutator. Therefore, continuous maintenance is required. However, three phase BLDC motors have higher power density compared to dc motors and the machine maintenance is not needed because electric commutation is possible. The three phase generally uses hall sensors to get position information and this enables the accurate control. This paper suggests an algorithm that compensates the errors occurred when the hall sensors have a breakdown for stable operation.