• Journal of Power Electronics
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• v.10 no.1
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• pp.85-90
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• 2010

In this paper the effects of a Static Synchronous Series Compensator, which is constructed with a 48-pulse inverter, on the power demand from the grid are studied. Extensive simulation studies were carried out in the MATLAB simulation environment to observe the compensation achieved by the SSSC and its effects on the line voltage, line current, phase angle and real/reactive power. The designed device is simulated in a power system which is comprised of a three phase power source, a transmission line, line inductance and load. The system parameters such as line voltage, line current, reactive power Q and real power P transmissions are observed both when the SSSC is connected to and disconnected from the power system. The motivation for modeling a SSSC from a multi-pulse inverter is to enhance the voltage waveform of the device and this is observed in the total harmonic distortion (THD) analysis performed at the end of the paper. According to the results, the power flow and phase angle can be controlled successfully by the new device through voltage injection. Finally a THD analysis is performed to see the harmonics content. The effect on the quality of the line voltage and current is acceptable according to international standards.

• Fire Science and Engineering
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• v.25 no.2
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• pp.132-137
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• 2011

A relationship between resisting moment and the structure of an automatic closure device is introduced for analyzing the effect of opening and closing condition on various fire door sizes in the pressurized room for smoke control system. The larger the size of fire door is, the more force is required for reaching to opening and closing conditions and there exists the design range of fire door in the pressurized room reflecting the closing time of fire door, rotative velocity, a relation between rotative angle and force and the efficiency of the automatic closure device.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1500-1503
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• 2003

One of the main goals in the rehabilitation of SCI patients is to enable the patient to stand and walk themselves. We are developing high-thrust powered gait orthosis(PGO) that use air muscle actuator(shadow robot Co., UK) to be assisted gait and rehabilitation purposes of them. We made of PD controller and measured hip joint angle by its load and the pressure to control air muscle of PGO. As a results, maximum flexion angle of hip joint is $20^{\circ}$, and angular velocity is 30.4${\pm}2.5^{\circ}/sec$, and then delay time of system was average 0.62${\pm}$0.03s. As the hip flexion angle and the pelvic angle is decreased during the gait with PGO, the patient can walk faster. By using the PGO, the energy consumption can also be decreased. therefore, the proposed PGO can be a very useful assitive device for the paraplegics to walk.

• KIEAE Journal
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• v.17 no.3
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• pp.99-106
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• 2017

Purpose: Most modern office buildings adopt the curtain wall system in order to provide occupants with the sense of openness and high-technology, which requires large window area. As a result, the amount of solar radiation increases, negatively affecting cooling load during the summer and increasing energy costs. However, the performance of window itself is not sufficiently controllable parameter to control thermal comfort and solar radiation. Therefore, a shading device such as venetian blind is required to control them and thus a variety of studies have been performed thus far. So, the purpose of this study is to improve the performance of blind through the development of blind control algorithm. Method: Among various input variables for the control of venetian blinds, the vertical solar radiation has been selected in this study as the primary input variable and the optimal control algorithm for venetian blinds were developed for each window orientation. Result: The developed optimal control algorithm has a positive effect on building energy savings.

• Journal of Power Electronics
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• v.6 no.3
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• pp.235-244
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• 2006

Recently, speed sensorless vector control for synchronous reluctance motors (SYRMs) has deserved attention because of its advantages. Although rotor angle calculation using flux estimation is a straightforward approach, the DC offset can cause an increasing pure integrator error in this estimator. In addition, this method is affected by parameter fluctuation. In this paper, to control the motor at the low speed region, a modified programmable cascaded low pass filter (MPCPLF) with sensorless online parameter identification based on a block pulse function is proposed. The use of the MPCLPF is suggested because in programmable, cascade low pass filters (PCLPF), which previously have been applied to induction motors, the drift increases vastly wl)en motor speed decreases. Parameter identification is also used because it does not depend on estimation accuracy and can solve parameter fluctuation effects. Thus, sensorless speed control in the low speed region is possible. The experimental system includes a PC-based control with real time Linux and an ALTERA Complex Programmable Logic Device (CPLD), to acquire data from sensors and to send commands to the system. The experimental results show the proposed method performs well, speed and angle estimation are correct. Also, parameter identification and sensorless vector control are achieved at low speed, as well as, as at high speed.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.11
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• pp.1038-1043
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• 2015

When the study on the relationship between the Head-of-Bed (HOB) angle and ventilator-associated pneumonia is performed, the fact that the HOB angle can only be measured intermittently imposes a significant limitation on the study. Therefore, there has been demand for the development of a device that can measure the HOB angle continuously. In this paper, we propose the rapid prototyping of an HOB measurement system using open-source hardware and software. The proposed system helps to maintain the HOB angle at a particular angle by displaying the angle and helps the medical study of pneumonia patients by enabling continuous data acquisition. Firstly, we eliminate the process of making an MCU board by utilizing an open-source hardware mbed LPC1768. Secondly, we reduce the software development time by using libraries and hence enabling the easy use of peripherals. Thirdly, for rapid prototyping, we build the enclosure of the proposed system using a 3D printer. The proposed system can be attached and detached to and from a bed. Therefore, we can attach it to the bed of a patient for whom measurement of the HOB angle is necessary. Finally, we check the measurement performance and the validity of the proposed system through an experiment utilizing an incremental encoder.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1386-1389
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• 2008

Conventional viewing angle switching electrode requires pixel division and additional liquid crystal panel. Hence the conventional viewing angle switching has low aperture ratio and high thickness. In this paper we proposed new viewing angle switching using hybrid aligned nematic mode by fringe-field electrode field (named HAN-FFS) with single liquid crystal panel. The fringe-field switching electrode is located at the bottom, and the additional common electrode is located at the top of the cell to control viewing angle. The proposed device is free from additional liquid crystal panel and pixel division. Consequently, the suggested structure has not only high aperture ratio but also show an excellent potential for viewing angle switching.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.9
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• pp.866-871
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• 2010

Gait analysis is essential for leg diagnosis and rehabilitation for the patients, the handicapped and the elderly. The use of 3D motion capture device for gait analysis is very common for gait analysis. However, this device has several shortcomings including limited workspace, visibility and high price. Instead, we developed gait estimation system using gyroscopes. This system provides gait information including the number of gaits, stride and walking distance. With four gyroscope (one for each leg's thigh and calf) outputs, the proposed gait modeling estimates the movements of the hip, the knees and the feet. Complete pedestrian localization is implemented with gait information and the heading angle estimated from the rate gyro and the magnetic compass measurements. The developed system is very useful for diagnosis and the rehabilitation of the pedestrian at the hospital. It is also useful for indoor localization of the pedestrians.

• Journal of computational fluids engineering
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• v.6 no.3
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• pp.27-31
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• 2001

For rapid and abrupt control of a missile in supersonic flight, side jet on a missile body is found to be a useful device as evidenced by recent missile development at several nations. The magnitude of the side jet and the duration of it decide the level of control of such a missile system. In this paper, the aerodynamic characteristics of the side jet device itself are examined in terms of key parameters such as the side jet nozzle geometry, the chamber pressure and temperature. Specifically attention is paid to the effect of the chamber shape between the straight nozzle and the bent nozzle by 90 degrees on the nozzle flow properties. The thrust magnitudes are compared between the two shapes. Whether the way the nozzle is bent at the joint affects the nozzle performance is also investigated. Effects of the length and the divergence angle of the nozzle on the thrust are also quantified among three different side jet nozzles.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.6
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• pp.663-669
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• 2011

This paper examines methods to estimate torque and angle in shoulder flexion from surface electromyography(sEMG) signals for intuitive and delicate control of robotic assistance device. Five muscles on the upper arm, three for shoulder flexion and two for shoulder extension, were used to offer favorable sEMG recording conditions in the estimation. The methods tested were the mean absolute value (MAV) with linear regression and the artificial neural network (ANN) method. An optimal condition was sought by varying combination of muscles used and the parameters in each method. The estimation performance was evaluated using the correlation values and normalized root mean square error values. In addition, we discussed their possible use as an estimation of motion intent of a user or as a command input in a physical human-machine interaction system.