• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.943-944
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• 2011

The position of the rotor in a spherical motor is usually measured by encoders. When using a encoder, It is possible to measure the angle in a very high resolution. However it is limited to measure a single-DOF using one encoder. So it is required to use 3 encoders to measure a 3-DOF. In order to connect the encoder and the motor, an additional mechanic linkages. Because of these reasons, it is difficult to apply it in various systems. Where the friction and inertia is increased when operating the motor. It could cause a negative effect in dynamic characteristic. In this paper present dual-image sensing system capable of measuring 3-DOF motions in real time eliminating the mechanical linkages. In addition we offer methods of converting sensors outputs to rotation angle which is used in the controller.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.3
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• pp.131-138
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• 2017

QR/NFC tags have been utilized in various fields like exhibition, museum, and so on, but they have a drawback that they are read-only fundamentally. We devise a novel device called a smart memory tag (below mem-tag) which is supplemented with the write function through combining a flash memory into a NFC tag. A mem-tag is composed of an NFC tag, an MCU, a flash memory, a bluetooth module, and a battery, and is inter-operating with smartphones via bluetooth communication. It can be used in a bulletin board to support writing replies and in a check-in service to verify the presence of the site. What matters is that users' inter-operations are borne to be asynchronous, which leads to the energy consumption to wait for users' actions. Sleep mechanisms and asynchronous MAC protocols used in ubiquotous sensor networks cannot avoid the consumption of battery. In this paper, we propose a touch and play scheme for minimizing the consumption of battery that the MCU wakes up and PLAY when a user TOUCH the mem-tag. We implemented the system to show that our scheme lets the mem-tag work 50 times longer than the sleep and wake-up scheme.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1488-1490
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• 2008

The gyroscope is the sensor for detecting the rotation in inertial reference frame and constitute the navigation system together an accelerometer. As the inertial reference equipment for attitude determination and control in the satellite, the mechanical gyroscope has been used but it bring the disturbance for mass unbalance so the disturbance give a bad influence to the observation satellite mission because the mechanical gyroscope has the rotation parts. During the launch, The mechanical gyroscope is weak in vibration, shock and has the defect of narrow operating temperature range so it need the special design in integration. Recently the low orbit observation satellite for seeking the high pointing accuracy of image camera payload accept the FOG(Fiber Optic Gyro) or RLG(Ring Laser Gyro) for the attitude determination and control. The Ring Laser Gyro makes use of the Sanac effect within a resonant ring cavity of a He-Ne laser and has more accuracy than the other gyros. It need the 1000V DC to create the He-Ne plasma in discharge tube. In this paper, the design process of the High Voltage Power Supply for RLG(Ring Laser Gyroscope) is described. The specification for High Voltage Power Supply(HVPS) is proposed. Also, The analysis of flyback converter topology is explained. The Design for the HVPS is composed of the inverter circuit, feedback control circuit, high frequency switching transformer design and voltage doubler circuit.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.3
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• pp.292-299
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• 1999

DC motors are widely used in many industrial fields as the actuator of the robot and the driving power motors of the electrical vehicle, Usually in the sensors of DC motors such as the encoder the tachogenerator and the potentiometer etc. are applied, But usage of these sensors results in the increased price and operating cost such that the application of the motors are limitted. To solve this problem another method to construct low cost control system is investigates. In this paper a new speed control method for DC motor is proposed. This method uses motor parameters instead of using speed or position sensors. In this way the angular velocity is estimated by the measure-ment values of the armature voltage and current instead of measuring the sensor signal. This paper presents an alorithm for estimating the angular velocity of DC motor The effectiveness of the proposed method is verified by experimental results. Also the applicability of the proposed method is presented by applying to the velocity contol of a wheeled mobile robot.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.89-97
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• 2014

As the digital control technologies in automotive industry have advanced, electronic control units(ECUs) play a key-role to improve system performance. Transmission control unit(TCU) is a shifting controller for automatic transmission of which major functions are to determine the shift and manage the shifting process considering the various sensor signal on transmission and driver's commands. As with any ECU in vehicle, TCU performs complex algorithms such as shift control, diagnostic and failsafe functions. However, firmware design analysis is hardly possible by the reverse engineering due to code protection. Transmission simulator is a hardware-in-the-loop simulator which enables TCU to work in normal mode by simulating the electrical signal of TCU interface. In this research, diagnosis and failsafe algorithm implemented on commercialized TCU is analyzed by using the transmission simulator that is developed for wheel loader construction vehicle. This paper gives various experimental results on the proportional solenoid current trajectories for different operating modes, error detection criterion and limphome mode gears for all the possible cases of clutch malfunction. The derived results for conventional TCU can be applied to the development of inherent TCU algorithms and the transmission simulator can also be utilized for the test of TCU to be developed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.353-354
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• 2014

An active vibration control technique of a time-varying cantilever beam is proposed in this study. A simple in-house coil sensor instead of expensive commercial sensors was used to measure the vibrational displacement of the beam. Active band pass filters and artificial neutral net works detect the frequencies, amplitudes, and phases of the main vibration mode. The time constants of the low pass filter representing the positive position feedback controller are updated in real-time, which generates the control voltage input to actuate the piezoelectric actuator and suppress the vibration. An experiment was successfully performed to verify the algorithm for a cantilever beam, which fundamental natural frequency arbitrarily varies between 9 Hz ~ 18 Hz. The present active vibration suppression technique can be applied to variety of structures which undergoes large variation of dynamic characteristics while operating.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.530-532
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• 2015

Nowadays, it is animately studied on IoT(Internet of Things) on the strength of development of the short-range communications technology and smart device. In this paper, it made a interface board which is capable of short-range communications networks based on embedded linux and Android OS (operating system). and we also made a IoT sensor module and device driver module. This devices are easily separated and changed and also simply embodied in IoT, and It was implemented using the Android app that allows you to control the sensors.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.1115-1118
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• 2015

Two wheel type electric vehicles driving with the electric motors for guard are used increasingly at the airport and harbor place to move between narrow indoors. This type two wheel electric vehicles are powerd by batteries and using the steering control apparatus including multi sensors and handle operating device for forward and backward, rotating moving. At this research, we design sensor interfacing electronic control system use only the center of foot balance without the handle type steering apparatus. This design is for safety of drivers at one's cornering.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.5
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• pp.204-212
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• 2002

In order to improve the reliability of high voltage rotating machines, it is necessary to understand the breakdown mechanism of stator windings. Especially partial discharge(PD) inception and growth are important in stator winding insulation. Recently, many research on the diagnosis of stator winding insulation for large rotating machines have been developed since the 1970s. Capacitive couplers have been the most widely used sensor for on-line partial discharge detection in rotating machines. This paper deals with the electrical on-line monitor characteristics of ceramic coupler(CC) which has been developed to continuously measure the PD activity in operating high voltage motor stator windings on site. We investigated the electrical characteristics(PD quantity, breakdown voltage and frequency response) to develop CC. This paper presents frequency characteristics and laboratory test result to compare conventional 80([F] epoxy-mica coupler(EMC) and 105[pF] CC for PD measurement with 6.6㎸ model stator windings.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.1
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• pp.9-16
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• 2012

This paper describes a measuring apparatus that can be used to appraise the effectiveness of nanofluids as new heat-transfer-enhancing fluids. A couple of apparatuses using fine hot wires as sensors have been proposed for this purpose; however, they have a technical weakness related to the uncertain working conditions of the sensor. The present method uses the convective heat transfer coefficient from a hot wire as an indication of the heat transfer effectiveness of the nanofluid, where the temperature of the wire remains constant during the experiment. The operating principle and experimental procedure are explained in detail, and the validity of the system is tested with pure base fluids. The effects of particle concentration, velocity, and temperature on the heat transfer coefficients of the nanofluids are discussed comprehensively using the experimental data for graphite nanolubrication oil.