• Journal of Institute of Control, Robotics and Systems
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• v.22 no.7
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• pp.519-523
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• 2016

This paper proposes a method of estimating the actuator faults of a hexacopter without using encoders when one or more of six actuators do not operate normally. In the case of the hexacopter, a Pseudo-Inverse matrix is generally used to obtain the rotational speed of the actuators because the matrix that transforms the rotational speed of the actuators into the thrust and torque of the body coordinate system is not a square matrix. However, the method based on the Pseudo-Inverse matrix cannot detect the actuator faults correctly because the Pseudo-Inverse matrix is approximate. In the proposed method, the actuator faults are estimated by modifying the transform matrix using the property that the actuators of the hexacopter are symmetrical. The simulation results show the effectiveness of the proposed method when faults occur in one or more of the six actuators.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.304-305
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• 2018

현재 공장 단지 내에 구비된 조명 시설은 SMPS, DC/DC컨버터 및 LED 램프 등이 하나의 모듈로써 구성되어 있다. 이처럼 일체형으로써 사고 및 고장 발생 시, 모듈 전체를 수리 또는 교체되어야 하므로 시간과 경제적으로 많은 불편이 따른다. 본 논문에서 제안하는 시스템은 각각을 분리한 집중형 LED 드라이버로써 정류기와 DC/DC 컨버터를 분리하여 구성하였다. 각각의 LED의 Dimming 제어를 위해서, 전력선에 주파수 성분을 첨가하여 주파수 정보에 따른 Dimming 제어를 실시함으로써, 따로 통신선 구비가 필요 없는 집중형 LED 구동 드라이버를 제안하였다. 제안하는 방식의 타당성을 검증하기 위해 PSIM 시뮬레이션을 통하여 그 과정을 증명하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.31-33
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• 2013

종래의 전구식 등명기의 경우 중량이 많이 나갈 뿐만 아니라 전구의 교체시기가 짧고 전력소모가 심하다는 문제가 있었다. 또한 5mm 포탄형 저휘도 LED램프의 경우에는 수명이 길고 저전력이라는 장점이 있으나, 근래에는 해상의 배후광이 높아져 개당 소비전력이 1W(와트) 이상인 고휘도 파워 LED를 광원으로서 채택하는 등명기가 등장하고 있는 실정이다. 그런데, 이러한 고휘도 파워 LED의 경우 종래의 포탄형 LED에 비하여 광도는 매우 높으나, 소비전력이 상대적으로 매우 높으며, 그에 따라 발열이 심하다는 문제가 있다. 따라서, 고휘도 파워 LED를 채용하여 등명기의 광도를 높이는 경우에는 반드시 방열 문제를 고려해야 한다. 그렇지 않으면, 고휘도 파워 LED의 발열로 인하여 제품이 안정적으로 구동할 수 없으며, 결국에는 관련 부품의 고장이나 파손으로 이어지기 때문이다. 본 연구는 종래의 전구식 램프나 저전력 포탄형 LED램프를 대체하여 고휘도 파워 LED램프를 광원으로 적용함에 있어, 등명기의 중량을 증가시키지 않는 구조로서 보다 효과가 우수한 방열기술을 개발하기 위한 것이다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.6
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• pp.1-8
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• 2016

As demand for paper cups markedly increases, this has brought about a requirement to develop fast paper cup forming machines. However, the fast manufacturing speed of these machines causes faults to occur more frequently in the final product. To reduce the possibility of producing faulty products, it is necessary to develop technologies to monitor the manufacturing process and diagnose the machine status. In this research, we selected the main driving axis of the forming machine for fault diagnosis. We searched the states of rotational elements related to the driving axis and suggested a fault diagnostic system based on spectrum analysis consisting of a real-time data acquisition device, accelerometers, and a diagnosis algorithm. To evaluate the developed fault diagnostic system, we performed experiments using a test station which resembles the actual paper cup forming machine. As a result, we were able to confirm that the proposed system was sufficiently feasible to diagnose any abnormalities in the operation of the paper cup forming machine.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.626-632
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• 2017

This paper describes a high power amplifier combining eight low power amplifiers using a radial power combiner with low insertion loss. The radial power combiner is a non-resonant type combiner with 8 input ports and is implemented by microstrip transmission line. The combiner characteristics designed at operating frequency of 1.045 GHz have an insertion loss of 0.7 dB and a return loss of more than 12 dB. Also, the low power amplifier used was designed with AFT27S010NT1 transistor and designed to satisfy the same gain, phase and constant output characteristic at operating frequency. The high power amplifier, which combiners the radial power combiner and the drive amplifier of 8 W output by driving low power amplifiers obtained the output characteristic of 33 W at operating frequency of 1.045 GHz. Also, the change of the output characteristic of the amplifier using the radial combiner was graceful degradation when the low power amplifier failed one by one.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.4
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• pp.40-46
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• 2006

It is required to develop a highly reliable attitude & orbit control system of satellite that is less expensive as the technology of satellite design & integration is recently matured dramatically. To accomodate this kind of needs, the two axis attitude control method for wheel-based momentum-biased satellite system whose momentum bias vector points to a certain direction(sun direction), is developed using simple but reliable sensors and actuator: three axis magnetometer and coarse sun sensor are used as sensors, and magnetic torque bars are used as actuator. Classical PD type controller design methodologies are applied on a satellite system for the two axis control with the proper assumptions. Nonlinear simulation results are included to demonstrate the long term stability and the performance of closed-loop system design results.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.11
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• pp.139-147
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• 2016

This study described the design scheme for each step of the production test for the Fire Control System(FCS) of the K-55A1 PIP business of Hanwha Thales since 2011. From the time of receipt of the product It is necessary to improve the FCS's reliability by using the Unit Test, burn-In test, System Test. FCS of K-55A1 acts as a 'head' that control the self-propelled howitzer, and connected with the electrical and physical connection of self-propelled howitzer's multiple unit (Inertial navigation systems(IN), Muzzle Velocity Radar (MVR)) for the normal operation without an inch of error in operating. We designed the production testing equipment automatically as much as possible and designed with the environment similar to the self-propelled howitzer. by using this production testing equipment, It should help for the strengthen national defense of the Republic of Korea.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.559-562
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• 2003

In this paper, we introduce a new method detecting thyristor faults of the power converter module in Control Rod Control System. When we control the currents in each coil of Control Rod Drive Mechanism by using the current control method, the current value can follow the current reference despite the faults like the missing phase or the diode acting. Comparing the fault current values with the normal current values, the bad transient characteristics of the abnormal current can make the operations of control rods incorrect. In this case, the information from the current trends cannot be enough to detect the fault occurrence in thyristors. Instead of the coil currents, the state of thyristors can be watched by measuring the coil voltages. In the existing system of Westinghouse type, the ripple detector takes charge of this task. But this detector has some shortcomings in the point of time for fault detection, we come to devise a new fault detection method solving the problems which belong to the ripple detector.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4742-4748
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• 2014

A semi-automatic clutch was developed for drivers of vehicles with manual transmission. The clutch is operated by pressing a switch on the gear stick without stepping on a clutch pedal when the driver wants to shift gears. To automatic control a clutch, driving information is provided by sensors installed under the vehicle. On the other hand, sensors are prone to failure under severe driving conditions and a long time is needed to install or repair these sensors in the vehicle. In this paper, a semi-automatic clutch that received driving information by CAN communication from the ECU was developed and a pneumatic actuator was used to operate the clutch. The semi-automatic clutch by a pneumatic cylinder was operated with a supply air pressure of more than 3bar.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.11
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• pp.1117-1124
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• 2011

An integrated fault detection and isolation method is proposed in this paper. The main objective of this paper is development fault detection, isolation and diagnosis algorithm based on the DKF (Decentralized Kalman Filter) and the bank of IMM (Interacting Multiple Model) filters using penalty scalar for both partial and total faults and the outlier detection algorithm for preventing false alarm also included. The proposed FDI (Fault Detection and Isolation) scheme is developed in four phases. In the first phase, the outlier detection filter is designed to prevent false alarm as a pre-filter. In the second phases, two local filters and master filter are designed to detect sensor faults. In the third phases, the proposed FDI scheme checks sensor residual to isolate sensor faults and 11 EKFs actuator fault models are designed to detect wherever actuator faults occur. In the last phases, four filters are designed to identify the fault type which is either the total fault or partial fault. The developed scheme can deal with not only sensor and actuator faults, but also preventing false alarm. An important feature of the proposed FDI scheme can decreases fault isolation time and figure out not only fault detection and isolation but also fault type identification. To verify the proposed FDI algorithm performance, the Simulator is also developed under the Matlab/Simulink environment.