• Proceedings of the KSME Conference
• /
• 2001.06d
• /
• pp.660-664
• /
• 2001

Ringbom Stirling engine which is a kind of low temperature difference model Stirling engine is manufactured and its characteristics are measured at some temperature differences. Pressure, displacer position and rotation speed are measured. Displacer position and rotation speed are detected by photo-sensor. The hot side of Ringbom Stirling engine is warmed by electric heater. The cold side of Ringbom Stirling engine is cooled by the air. This result may be useful for further design and manufacture of Ringbom Stirling engine. Also, it would be used as an educational material for mechanical engineering students.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.28 no.1
• /
• pp.46-50
• /
• 2015

The cable degradation process is largely divided into three steps; Step 1 : Thermal degradation, Step 2 : Weibull degradation, Step 3 : Partial discharge. it is progress in step order. This article aims to explain the process of cable degradation using the method of insulation resistance and accordingly to compose and manufacture a system of measuring the life of electrical cable. Before measuring the insulation resistance, a system of measuring the temperature and current of cables was made, and the established system was installed for test on the site of a power plant to collect the measured data. The current sensor was used TFC30P80A-CL420, and temperature sensor was used the DK-1270 PT100 sensor as RTD sensor. When measured the temperature and the load current at the same position, was confirmed that in case of the load current value was high, also temperature value high. Therefore, the correlation between load currents and temperature was verified, and the analysis of diagnostic data was evaluated, which could be utilized in identifying the fault condition of cable systems.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.43 no.1 s.307
• /
• pp.1-6
• /
• 2006

The noncontact optical sensor using the hologram laser and automatic power controller is developed to measure a thickness of transparent objects and achieve excellent performance. Due to the contact between the tip of the sensor and the surface of objects, the tip is abraded. In addition the casting glass under high temperature results in extending the size of sensor body. The accuracy of the sensor is degraded due to these reasons. In this paper, to overcome these problems, we proposed a low cost non-contact optical sensor that is composed of a hologram laser unit used for optical pickup of CD player and a plastic lens. Therefore the problems caused by the contact sensor are solved by using the noncontact sensor. The noncontact sensor has to move toward the objects and obtain the focus error signal to measure a position of transparent objects. While the internal temperature of the sensor is controlled under ${\pm}0.1^{\circ}$, many trials shows ${\pm}2{\mu}m$ measurement error as excellent performance.

• Proceedings of the SAREK Conference
• /
• 2007.11a
• /
• pp.191-196
• /
• 2007

This paper presents the measuring technique for local heat transfer coefficients using a copper sensor in a rod bundle with mixing vanes. A copper sensor consists of a cartridge heater and four pieces of thermocouple. The Heater is located at the center of the copper sensor and thermocouples measure the surface temperature of the copper sensor. Unheated copper sensor and heated copper sensor are able to measure the local heat transfer coefficient at the position where the heated copper sensor is installed. However the entire region of a rod bundle is actually not heated, the decay of local heat transfer coefficients measured represents overestimated value rather than an actual value. The calibration curve for local heat transfer coefficients is presented using the correction factor calculated by CFD.

• Journal of Institute of Control, Robotics and Systems
• /
• v.13 no.7
• /
• pp.637-648
• /
• 2007

This paper presents a sensor fusion method based on indirect Kalman filter(IKF) for error compensation of low-cost inertial sensors and its application to the determination of attitude and position of small flying robots. First, the analysis of the measurement error characteristics to zero input is performed, focusing on the bias due to the temperature variation, to derive a simple nonlinear bias model of low-cost inertial sensors. Moreover, from the experimental results that the coefficients of this bias model possess non-deterministic (stochastic) uncertainties, the bias of low-cost inertial sensors is characterized as consisting of both deterministic and stochastic bias terms. Then, IKF is derived to improve long term stability dominated by the stochastic bias error, fusing low-cost inertial sensor measurements compensated by the deterministic bias model with non-inertial sensor measurement. In addition, in case of using intermittent non-inertial sensor measurements due to the unreliable data link, the upper and lower bounds of the state estimation error covariance matrix of discrete-time IKF are analyzed by solving stochastic algebraic Riccati equation and it is shown that they are dependant on the throughput of the data link and sampling period. To evaluate the performance of proposed method, experimental results of IKF for the attitude determination of a small flying robot are presented in comparison with that of extended Kaman filter which compensates only deterministic bias error model.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.39 no.12
• /
• pp.935-943
• /
• 2015

This paper presents a method for early fire detection and fire position determination inside the nacelle of wind turbine generator system. The rising temperature and obscuration rates inside the nacelle were used as parameters for fire detection, which can minimize the possibility of a fire detection malfunction because these rising rates do not depend on the absolute values of temperature and obscuration. The fire position was determined using the time difference among various sensor positions for fire detection. The performance of the method was tasted using sets of experiments in a nacelle simulator.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.22 no.2
• /
• pp.189-196
• /
• 2019

The inertial sensor errors in SDINS(Strapdown Inertial Navigation System) can be compensated by rotating the inertial measurement unit and it is called RINS(Rotational Inertial Navigation System). It is assumed that the error of the inertial sensor in RINS is a static bias. However, the error of the inertial sensor actually developed and produced is not a static bias due to the change of the temperature applied to the sensor and the influence of the earth's gravity acceleration. In this paper, we propose a six-position gyro bias calibration method to evaluate the gyro bias required for RINS and present the test results of applying it to a ring laser gyro inertial navigation system under development.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.5 no.2
• /
• pp.164-170
• /
• 2010

In brushless DC motor, current flow should be controlled such that only properly selected 2 out of 3 phases carry current depending on the position of rotor. In order to detect position of rotor, hole sensor, encoder, optical position-detecting sensor, and magnetic position-detecting sensor are frequently employed. These sensors not only often cause malfunction in low and high temperature but they also have disadvantage of increasing cost and size of an motor system. To reduce the cost and size and to increase the robustness of the motor system, recently researches on sensorless motor dirve are very active. This paper proposes a novel unipolar PWM switching method that can improve the control problem caused by the difficulty of detecting zero crossing point at high revolution speed by minimizing the switching noise while increasing the lifespan of the drive system.

• Journal of ILASS-Korea
• /
• v.16 no.2
• /
• pp.76-81
• /
• 2011

A fuel injection system which is operated with a real vehicle driving simulation was developed as an alternative to a vehicle test for the fuel injectors. The sensor signals that are supplied to the ECU were measured and recorded as a data file for a vehicle driven in FTP-75 mode in a chassis dynamometer. The imperative sensor signals of the throttle position, vehicle speed, engine speed, crank position, cam position, intake air flow, and cooling water and intake air temperature were reconstructed using FPGA DAQ boards and a PXI computer. The scanning results showed good agreement with the input signals that were reconstructed. The ECU HILS system operated successfully to drive six fuel injectors, which injected fuel in the same pattern as if they were mounted in the vehicle driven in FTP-75 mode. Also, the fuel injection system developed in this research shows the possibility of application in evaluating the characteristics of fuel injection rate for injectors according to properties of injected fuel with the real driving mode of vehicles.

• Proceedings of the KIEE Conference
• /
• 1997.07b
• /
• pp.524-526
• /
• 1997

We have developed a part of hydraulic stroke sensing cylinder using magnetic sensor that can detect each position under severe construction fields. In this paper, for evaluating the developed cylinder under various environment condition, temperature control systems and two hydraulic systems to be coupled consist of. The results show that the developed cylinder has good performance under the various environment condition.